Previous standalone version of data analysis routines added as part of legacy code archive.

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Karthik 2025-08-18 10:29:17 +02:00
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function results = analyzeFolder(options)
% Ensure required fields are defined in options
arguments
options.scan_parameter (1,:) char
options.scan_groups (1,:) double
options.cam (1,1) double
options.angle (1,1) double
options.center (1,2) double
options.span (1,2) double
options.fraction (1,2) double
options.ImagingMode (1,:) char
options.PulseDuration (1,1) double
options.removeFringes (1,1) logical
options.skipUnshuffling (1,1) logical
options.pixel_size (1,1) double
options.magnification (1,1) double
options.zoom_size (1,1) double
options.r_min (1,1) double
options.r_max (1,1) double
options.N_angular_bins (1,1) double
options.Angular_Threshold (1,1) double
options.Angular_Sigma (1,1) double
options.Angular_WindowSize (1,1) double
options.theta_min (1,1) double
options.theta_max (1,1) double
options.N_radial_bins (1,1) double
options.Radial_Sigma (1,1) double
options.Radial_WindowSize (1,1) double
options.k_min (1,1) double
options.k_max (1,1) double
options.skipPreprocessing (1,1) logical
options.skipMasking (1,1) logical
options.skipIntensityThresholding (1,1) logical
options.skipBinarization (1,1) logical
options.folderPath (1,:) char
end
% Assign variables from options
scan_parameter = options.scan_parameter;
scan_groups = options.scan_groups;
folderPath = options.folderPath;
center = options.center;
span = options.span;
fraction = options.fraction;
ImagingMode = options.ImagingMode;
PulseDuration = options.PulseDuration;
removeFringes = options.removeFringes;
skipUnshuffling = options.skipUnshuffling;
pixel_size = options.pixel_size;
magnification = options.magnification;
zoom_size = options.zoom_size;
r_min = options.r_min;
r_max = options.r_max;
N_angular_bins = options.N_angular_bins;
Angular_Threshold = options.Angular_Threshold;
Angular_Sigma = options.Angular_Sigma;
Angular_WindowSize = options.Angular_WindowSize;
theta_min = options.theta_min;
theta_max = options.theta_max;
N_radial_bins = options.N_radial_bins;
Radial_Sigma = options.Radial_Sigma;
Radial_WindowSize = options.Radial_WindowSize;
k_min = options.k_min;
k_max = options.k_max;
skipPreprocessing = options.skipPreprocessing;
skipMasking = options.skipMasking;
skipIntensityThresholding = options.skipIntensityThresholding;
skipBinarization = options.skipBinarization;
cam = options.cam;
angle = options.angle;
% Load images and analyze them (keep using the cleaned body of your original function)
% Fix the incorrect usage of 'cam' and 'angle' not defined locally
groupList = ["/images/MOT_3D_Camera/in_situ_absorption",
"/images/ODT_1_Axis_Camera/in_situ_absorption",
"/images/ODT_2_Axis_Camera/in_situ_absorption",
"/images/Horizontal_Axis_Camera/in_situ_absorption",
"/images/Vertical_Axis_Camera/in_situ_absorption"];
filePattern = fullfile(folderPath, '*.h5');
files = dir(filePattern);
refimages = zeros(span(1) + 1, span(2) + 1, length(files));
absimages = zeros(span(1) + 1, span(2) + 1, length(files));
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
fprintf(1, 'Now reading %s\n', fullFileName);
atm_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/atoms")), angle));
bkg_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/background")), angle));
dark_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/dark")), angle));
if (isempty(atm_img) && isa(atm_img, 'double')) || ...
(isempty(bkg_img) && isa(bkg_img, 'double')) || ...
(isempty(dark_img) && isa(dark_img, 'double'))
refimages(:,:,k) = nan(size(refimages(:,:,k))); % fill with NaNs
absimages(:,:,k) = nan(size(absimages(:,:,k)));
else
refimages(:,:,k) = subtractBackgroundOffset(cropODImage(bkg_img, center, span), fraction)';
absimages(:,:,k) = subtractBackgroundOffset(cropODImage(calculateODImage(atm_img, bkg_img, dark_img, ImagingMode, PulseDuration), center, span), fraction)';
end
end
% ===== Fringe removal =====
if removeFringes
optrefimages = removefringesInImage(absimages, refimages);
absimages_fringe_removed = absimages(:, :, :) - optrefimages(:, :, :);
nimgs = size(absimages_fringe_removed,3);
od_imgs = cell(1, nimgs);
for i = 1:nimgs
od_imgs{i} = absimages_fringe_removed(:, :, i);
end
else
nimgs = size(absimages(:, :, :),3);
od_imgs = cell(1, nimgs);
for i = 1:nimgs
od_imgs{i} = absimages(:, :, i);
end
end
% ===== Get rotation angles =====
scan_parameter_values = zeros(1, length(files));
% Get information about the '/globals' group
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
info = h5info(fullFileName, '/globals');
for i = 1:length(info.Attributes)
if strcmp(info.Attributes(i).Name, scan_parameter)
if strcmp(scan_parameter, 'rot_mag_fin_pol_angle')
scan_parameter_values(k) = 180 - info.Attributes(i).Value;
else
scan_parameter_values(k) = info.Attributes(i).Value;
end
end
end
end
% ===== Unshuffle if necessary to do so =====
if ~skipUnshuffling
n_values = length(scan_groups);
n_total = length(scan_parameter_values);
% Infer number of repetitions
n_reps = n_total / n_values;
% Preallocate ordered arrays
ordered_scan_values = zeros(1, n_total);
ordered_od_imgs = cell(1, n_total);
counter = 1;
for rep = 1:n_reps
for val = scan_groups
% Find the next unused match for this val
idx = find(scan_parameter_values == val, 1, 'first');
% Assign and remove from list to avoid duplicates
ordered_scan_values(counter) = scan_parameter_values(idx);
ordered_od_imgs{counter} = od_imgs{idx};
% Mark as used by removing
scan_parameter_values(idx) = NaN; % NaN is safe since original values are 0:5:45
od_imgs{idx} = []; % empty cell so it won't be matched again
counter = counter + 1;
end
end
% Now assign back
scan_parameter_values = ordered_scan_values;
od_imgs = ordered_od_imgs;
end
% Extract quantities
fft_imgs = cell(1, nimgs);
spectral_distribution = cell(1, nimgs);
theta_values = cell(1, nimgs);
radial_spectral_contrast = zeros(1, nimgs);
angular_spectral_weight = zeros(1, nimgs);
N_shots = length(od_imgs);
for k = 1:N_shots
IMG = od_imgs{k};
if ~(max(IMG(:)) > 1)
IMGFFT = NaN(size(IMG));
else
[IMGFFT, IMGPR] = computeFourierTransform(IMG, skipPreprocessing, skipMasking, skipIntensityThresholding, skipBinarization);
end
% Size of original image (in pixels)
[Ny, Nx] = size(IMG);
% Real-space pixel size in micrometers after magnification
dx = pixel_size / magnification;
dy = dx; % assuming square pixels
% Real-space axes
x = ((1:Nx) - ceil(Nx/2)) * dx * 1E6;
y = ((1:Ny) - ceil(Ny/2)) * dy * 1E6;
% Reciprocal space increments (frequency domain, μm¹)
dvx = 1 / (Nx * dx);
dvy = 1 / (Ny * dy);
% Frequency axes
vx = (-floor(Nx/2):ceil(Nx/2)-1) * dvx;
vy = (-floor(Ny/2):ceil(Ny/2)-1) * dvy;
% Wavenumber axes
kx_full = 2 * pi * vx * 1E-6; % μm¹
ky_full = 2 * pi * vy * 1E-6;
% Crop FFT image around center
mid_x = floor(Nx/2);
mid_y = floor(Ny/2);
fft_imgs{k} = IMGFFT(mid_y-zoom_size:mid_y+zoom_size, mid_x-zoom_size:mid_x+zoom_size);
% Crop wavenumber axes to match fft_imgs{k}
kx = kx_full(mid_x - zoom_size : mid_x + zoom_size);
ky = ky_full(mid_y - zoom_size : mid_y + zoom_size);
[theta_vals, S_theta] = computeAngularSpectralDistribution(fft_imgs{k}, kx, ky, k_min, k_max, N_angular_bins, Angular_Threshold, Angular_Sigma, []);
[k_rho_vals, S_k] = computeRadialSpectralDistribution(fft_imgs{k}, kx, ky, theta_min, theta_max, N_radial_bins);
S_k_smoothed = movmean(S_k, Radial_WindowSize); % Compute moving average (use convolution) or use conv for more control
spectral_distribution{k} = S_theta;
theta_values{k} = theta_vals;
radial_spectral_contrast(k) = computeRadialSpectralContrast(k_rho_vals, S_k_smoothed, k_min, k_max);
S_theta_norm = S_theta / max(S_theta); % Normalize to 1
angular_spectral_weight(k) = trapz(theta_vals, S_theta_norm);
end
% Assuming scan_parameter_values and spectral_weight are column vectors (or row vectors of same length)
[unique_scan_parameter_values, ~, idx] = unique(scan_parameter_values);
% Preallocate arrays
mean_rsc = zeros(size(unique_scan_parameter_values));
stderr_rsc = zeros(size(unique_scan_parameter_values));
% Loop through each unique theta and compute mean and standard error
for i = 1:length(unique_scan_parameter_values)
group_vals = radial_spectral_contrast(idx == i);
mean_rsc(i) = mean(group_vals, 'omitnan');
stderr_rsc(i) = std(group_vals, 'omitnan') / sqrt(length(group_vals)); % standard error = std / sqrt(N)
end
% Preallocate arrays
mean_asw = zeros(size(unique_scan_parameter_values));
stderr_asw = zeros(size(unique_scan_parameter_values));
% Loop through each unique theta and compute mean and standard error
for i = 1:length(unique_scan_parameter_values)
group_vals = angular_spectral_weight(idx == i);
mean_asw(i) = mean(group_vals, 'omitnan');
stderr_asw(i) = std(group_vals, 'omitnan') / sqrt(length(group_vals)); % standard error = std / sqrt(N)
end
% Convert spectral distribution to matrix (N_shots x N_angular_bins)
delta_nkr_all = zeros(N_shots, N_angular_bins);
for k = 1:N_shots
delta_nkr_all(k, :) = spectral_distribution{k};
end
% Group by scan parameter values (e.g., alpha, angle, etc.)
[unique_scan_parameter_values, ~, idx] = unique(scan_parameter_values);
N_params = length(unique_scan_parameter_values);
% Define angular range and conversion
angle_range = 180;
angle_per_bin = angle_range / N_angular_bins;
max_peak_angle = 180;
max_peak_bin = round(max_peak_angle / angle_per_bin);
% Parameters for search
window_size = 10;
angle_threshold = 100;
% Initialize containers for final results
mean_max_g2_values = zeros(1, N_params);
mean_max_g2_angle_values = zeros(1, N_params);
var_max_g2_values = zeros(1, N_params);
var_max_g2_angle_values = zeros(1, N_params);
std_error_g2_values = zeros(1, N_params);
% Also store raw data per group
g2_all_per_group = cell(1, N_params);
angle_all_per_group = cell(1, N_params);
for i = 1:N_params
group_idx = find(idx == i);
group_data = delta_nkr_all(group_idx, :);
N_reps = size(group_data, 1);
g2_values = zeros(1, N_reps);
angle_at_max_g2 = zeros(1, N_reps);
for j = 1:N_reps
profile = group_data(j, :);
% Restrict search to 060° for highest peak
restricted_profile = profile(1:max_peak_bin);
[~, peak_idx_rel] = max(restricted_profile);
peak_idx = peak_idx_rel;
peak_angle = (peak_idx - 1) * angle_per_bin;
if peak_angle < angle_threshold
offsets = round(50 / angle_per_bin) : round(70 / angle_per_bin);
else
offsets = -round(70 / angle_per_bin) : -round(50 / angle_per_bin);
end
ref_window = mod((peak_idx - window_size):(peak_idx + window_size) - 1, N_angular_bins) + 1;
ref = profile(ref_window);
correlations = zeros(size(offsets));
angles = zeros(size(offsets));
for k = 1:length(offsets)
shifted_idx = mod(peak_idx + offsets(k) - 1, N_angular_bins) + 1;
sec_window = mod((shifted_idx - window_size):(shifted_idx + window_size) - 1, N_angular_bins) + 1;
sec = profile(sec_window);
num = mean(ref .* sec, 'omitnan');
denom = mean(ref.^2, 'omitnan');
g2 = num / denom;
correlations(k) = g2;
angles(k) = mod((peak_idx - 1 + offsets(k)) * angle_per_bin, angle_range);
end
[max_corr, max_idx] = max(correlations);
g2_values(j) = max_corr;
angle_at_max_g2(j) = angles(max_idx);
end
% Store raw values
g2_all_per_group{i} = g2_values;
angle_all_per_group{i} = angle_at_max_g2;
% Final stats
mean_max_g2_values(i) = mean(g2_values, 'omitnan');
var_max_g2_values(i) = var(g2_values, 0, 'omitnan');
mean_max_g2_angle_values(i)= mean(angle_at_max_g2, 'omitnan');
var_max_g2_angle_values(i) = var(angle_at_max_g2, 0, 'omitnan');
n_i = numel(g2_all_per_group{i}); % Number of repetitions for this param
std_error_g2_values(i) = sqrt(var_max_g2_values(i) / n_i);
end
results.folderPath = folderPath;
results.scan_parameter = scan_parameter;
results.scan_groups = scan_groups;
results.mean_max_g2_values = mean_max_g2_values;
results.std_error_g2_values = std_error_g2_values;
results.mean_max_g2_angle = mean_max_g2_angle_values;
results.radial_spectral_contrast= mean_rsc;
results.angular_spectral_weight = mean_asw;
end
%% Helper Functions
function [IMGFFT, IMGPR] = computeFourierTransform(I, skipPreprocessing, skipMasking, skipIntensityThresholding, skipBinarization)
% computeFourierSpectrum - Computes the 2D Fourier power spectrum
% of binarized and enhanced lattice image features, with optional central mask.
%
% Inputs:
% I - Grayscale or RGB image matrix
%
% Output:
% F_mag - 2D Fourier power spectrum (shifted)
if ~skipPreprocessing
% Preprocessing: Denoise
filtered = imgaussfilt(I, 10);
IMGPR = I - filtered; % adjust sigma as needed
else
IMGPR = I;
end
if ~skipMasking
[rows, cols] = size(IMGPR);
[X, Y] = meshgrid(1:cols, 1:rows);
% Elliptical mask parameters
cx = cols / 2;
cy = rows / 2;
% Shifted coordinates
x = X - cx;
y = Y - cy;
% Ellipse semi-axes
rx = 0.4 * cols;
ry = 0.2 * rows;
% Rotation angle in degrees -> radians
theta_deg = 30; % Adjust as needed
theta = deg2rad(theta_deg);
% Rotated ellipse equation
cos_t = cos(theta);
sin_t = sin(theta);
x_rot = (x * cos_t + y * sin_t);
y_rot = (-x * sin_t + y * cos_t);
ellipseMask = (x_rot.^2) / rx^2 + (y_rot.^2) / ry^2 <= 1;
% Apply cutout mask
IMGPR = IMGPR .* ellipseMask;
end
if ~skipIntensityThresholding
% Apply global intensity threshold mask
intensity_thresh = 0.20;
intensity_mask = IMGPR > intensity_thresh;
IMGPR = IMGPR .* intensity_mask;
end
if ~skipBinarization
% Adaptive binarization and cleanup
IMGPR = imbinarize(IMGPR, 'adaptive', 'Sensitivity', 0.0);
IMGPR = imdilate(IMGPR, strel('disk', 2));
IMGPR = imerode(IMGPR, strel('disk', 1));
IMGPR = imfill(IMGPR, 'holes');
F = fft2(double(IMGPR)); % Compute 2D Fourier Transform
IMGFFT = abs(fftshift(F))'; % Shift zero frequency to center
else
F = fft2(double(IMGPR)); % Compute 2D Fourier Transform
IMGFFT = abs(fftshift(F))'; % Shift zero frequency to center
end
end
function [k_rho_vals, S_radial] = computeRadialSpectralDistribution(IMGFFT, kx, ky, thetamin, thetamax, num_bins)
% IMGFFT : 2D FFT image (fftshifted and cropped)
% kx, ky : 1D physical wavenumber axes [μm¹] matching FFT size
% thetamin : Minimum angle (in radians)
% thetamax : Maximum angle (in radians)
% num_bins : Number of radial bins
[KX, KY] = meshgrid(kx, ky);
K_rho = sqrt(KX.^2 + KY.^2);
Theta = atan2(KY, KX);
if thetamin < thetamax
angle_mask = (Theta >= thetamin) & (Theta <= thetamax);
else
angle_mask = (Theta >= thetamin) | (Theta <= thetamax);
end
power_spectrum = abs(IMGFFT).^2;
r_min = min(K_rho(angle_mask));
r_max = max(K_rho(angle_mask));
r_edges = linspace(r_min, r_max, num_bins + 1);
k_rho_vals = 0.5 * (r_edges(1:end-1) + r_edges(2:end));
S_radial = zeros(1, num_bins);
for i = 1:num_bins
r_low = r_edges(i);
r_high = r_edges(i + 1);
radial_mask = (K_rho >= r_low) & (K_rho < r_high);
full_mask = radial_mask & angle_mask;
S_radial(i) = sum(power_spectrum(full_mask));
end
end
function [theta_vals, S_theta] = computeAngularSpectralDistribution(IMGFFT, kx, ky, k_min, k_max, num_bins, threshold, sigma, windowSize)
% Apply threshold to isolate strong peaks
IMGFFT(IMGFFT < threshold) = 0;
% Create wavenumber meshgrid
[KX, KY] = meshgrid(kx, ky);
Kmag = sqrt(KX.^2 + KY.^2); % radial wavenumber magnitude
Theta = atan2(KY, KX); % range [-pi, pi]
% Restrict to radial band in wavenumber space
radial_mask = (Kmag >= k_min) & (Kmag <= k_max);
% Initialize angular structure factor
S_theta = zeros(1, num_bins);
theta_vals = linspace(0, pi, num_bins); % only 0 to pi due to symmetry
% Loop over angular bins
for i = 1:num_bins
angle_start = (i - 1) * pi / num_bins;
angle_end = i * pi / num_bins;
angle_mask = (Theta >= angle_start) & (Theta < angle_end);
bin_mask = radial_mask & angle_mask;
fft_angle = IMGFFT .* bin_mask;
S_theta(i) = sum(sum(abs(fft_angle).^2));
end
% Optional smoothing
if exist('sigma', 'var') && ~isempty(sigma)
% Gaussian smoothing
half_width = ceil(3 * sigma);
x = -half_width:half_width;
gauss_kernel = exp(-x.^2 / (2 * sigma^2));
gauss_kernel = gauss_kernel / sum(gauss_kernel);
% Circular convolution
S_theta = conv([S_theta(end - half_width + 1:end), S_theta, S_theta(1:half_width)], ...
gauss_kernel, 'same');
S_theta = S_theta(half_width + 1:end - half_width);
elseif exist('windowSize', 'var') && ~isempty(windowSize)
% Moving average smoothing
pad = floor(windowSize / 2);
kernel = ones(1, windowSize) / windowSize;
S_theta = conv([S_theta(end - pad + 1:end), S_theta, S_theta(1:pad)], kernel, 'same');
S_theta = S_theta(pad + 1:end - pad);
end
end
function contrast = computeRadialSpectralContrast(k_rho_vals, S_k_smoothed, k_min, k_max)
% Computes the ratio of the peak in S_k_smoothed within [k_min, k_max]
% to the value at (or near) k = 0.
% Ensure inputs are column vectors
k_rho_vals = k_rho_vals(:);
S_k_smoothed = S_k_smoothed(:);
% Step 1: Find index of k 0
[~, idx_k0] = min(abs(k_rho_vals)); % Closest to zero
S_k0 = S_k_smoothed(idx_k0);
% Step 2: Find indices in specified k-range
in_range = (k_rho_vals >= k_min) & (k_rho_vals <= k_max);
if ~any(in_range)
warning('No values found in the specified k-range. Returning NaN.');
contrast = NaN;
return;
end
% Step 3: Find peak value in the specified k-range
S_k_peak = max(S_k_smoothed(in_range));
% Step 4: Compute contrast
contrast = S_k_peak / S_k0;
end
function ret = getBkgOffsetFromCorners(img, x_fraction, y_fraction)
% image must be a 2D numerical array
[dim1, dim2] = size(img);
s1 = img(1:round(dim1 * y_fraction), 1:round(dim2 * x_fraction));
s2 = img(1:round(dim1 * y_fraction), round(dim2 - dim2 * x_fraction):dim2);
s3 = img(round(dim1 - dim1 * y_fraction):dim1, 1:round(dim2 * x_fraction));
s4 = img(round(dim1 - dim1 * y_fraction):dim1, round(dim2 - dim2 * x_fraction):dim2);
ret = mean([mean(s1(:)), mean(s2(:)), mean(s3(:)), mean(s4(:))]);
end
function ret = subtractBackgroundOffset(img, fraction)
% Remove the background from the image.
% :param dataArray: The image
% :type dataArray: xarray DataArray
% :param x_fraction: The fraction of the pixels used in x axis
% :type x_fraction: float
% :param y_fraction: The fraction of the pixels used in y axis
% :type y_fraction: float
% :return: The image after removing background
% :rtype: xarray DataArray
x_fraction = fraction(1);
y_fraction = fraction(2);
offset = getBkgOffsetFromCorners(img, x_fraction, y_fraction);
ret = img - offset;
end
function ret = cropODImage(img, center, span)
% Crop the image according to the region of interest (ROI).
% :param dataSet: The images
% :type dataSet: xarray DataArray or DataSet
% :param center: The center of region of interest (ROI)
% :type center: tuple
% :param span: The span of region of interest (ROI)
% :type span: tuple
% :return: The cropped images
% :rtype: xarray DataArray or DataSet
x_start = floor(center(1) - span(1) / 2);
x_end = floor(center(1) + span(1) / 2);
y_start = floor(center(2) - span(2) / 2);
y_end = floor(center(2) + span(2) / 2);
ret = img(y_start:y_end, x_start:x_end);
end
function imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%CALCULATEODIMAGE Calculates the optical density (OD) image for absorption imaging.
%
% imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%
% Inputs:
% imageAtom - Image with atoms
% imageBackground - Image without atoms
% imageDark - Image without light
% mode - 'LowIntensity' (default) or 'HighIntensity'
% exposureTime - Required only for 'HighIntensity' [in seconds]
%
% Output:
% imageOD - Computed OD image
%
arguments
imageAtom (:,:) {mustBeNumeric}
imageBackground (:,:) {mustBeNumeric}
imageDark (:,:) {mustBeNumeric}
mode char {mustBeMember(mode, {'LowIntensity', 'HighIntensity'})} = 'LowIntensity'
exposureTime double = NaN
end
% Compute numerator and denominator
numerator = imageBackground - imageDark;
denominator = imageAtom - imageDark;
% Avoid division by zero
numerator(numerator == 0) = 1;
denominator(denominator == 0) = 1;
% Calculate OD based on mode
switch mode
case 'LowIntensity'
imageOD = -log(abs(denominator ./ numerator));
case 'HighIntensity'
if isnan(exposureTime)
error('Exposure time must be provided for HighIntensity mode.');
end
imageOD = abs(denominator ./ numerator);
imageOD = -log(imageOD) + (numerator - denominator) ./ (7000 * (exposureTime / 5e-6));
end
end
function [optrefimages] = removefringesInImage(absimages, refimages, bgmask)
% removefringesInImage - Fringe removal and noise reduction from absorption images.
% Creates an optimal reference image for each absorption image in a set as
% a linear combination of reference images, with coefficients chosen to
% minimize the least-squares residuals between each absorption image and
% the optimal reference image. The coefficients are obtained by solving a
% linear set of equations using matrix inverse by LU decomposition.
%
% Application of the algorithm is described in C. F. Ockeloen et al, Improved
% detection of small atom numbers through image processing, arXiv:1007.2136 (2010).
%
% Syntax:
% [optrefimages] = removefringesInImage(absimages,refimages,bgmask);
%
% Required inputs:
% absimages - Absorption image data,
% typically 16 bit grayscale images
% refimages - Raw reference image data
% absimages and refimages are both cell arrays containing
% 2D array data. The number of refimages can differ from the
% number of absimages.
%
% Optional inputs:
% bgmask - Array specifying background region used,
% 1=background, 0=data. Defaults to all ones.
% Outputs:
% optrefimages - Cell array of optimal reference images,
% equal in size to absimages.
%
% Dependencies: none
%
% Authors: Shannon Whitlock, Caspar Ockeloen
% Reference: C. F. Ockeloen, A. F. Tauschinsky, R. J. C. Spreeuw, and
% S. Whitlock, Improved detection of small atom numbers through
% image processing, arXiv:1007.2136
% Email:
% May 2009; Last revision: 11 August 2010
% Process inputs
% Set variables, and flatten absorption and reference images
nimgs = size(absimages,3);
nimgsR = size(refimages,3);
xdim = size(absimages(:,:,1),2);
ydim = size(absimages(:,:,1),1);
R = single(reshape(refimages,xdim*ydim,nimgsR));
A = single(reshape(absimages,xdim*ydim,nimgs));
optrefimages=zeros(size(absimages)); % preallocate
if not(exist('bgmask','var')); bgmask=ones(ydim,xdim); end
k = find(bgmask(:)==1); % Index k specifying background region
% Ensure there are no duplicate reference images
% R=unique(R','rows')'; % comment this line if you run out of memory
% Decompose B = R*R' using singular value or LU decomposition
[L,U,p] = lu(R(k,:)'*R(k,:),'vector'); % LU decomposition
for j=1:nimgs
b=R(k,:)'*A(k,j);
% Obtain coefficients c which minimise least-square residuals
lower.LT = true; upper.UT = true;
c = linsolve(U,linsolve(L,b(p,:),lower),upper);
% Compute optimised reference image
optrefimages(:,:,j)=reshape(R*c,[ydim xdim]);
end
end

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%% Extract Images
clear; close all; clc;
%% ===== D-S Settings =====
groupList = ["/images/MOT_3D_Camera/in_situ_absorption", "/images/ODT_1_Axis_Camera/in_situ_absorption", ...
"/images/ODT_2_Axis_Camera/in_situ_absorption", "/images/Horizontal_Axis_Camera/in_situ_absorption", ...
"/images/Vertical_Axis_Camera/in_situ_absorption"];
folderPath = "//DyLabNAS/Data/TwoDGas/2025/06/23/";
run = '0300';
folderPath = strcat(folderPath, run);
cam = 5;
angle = 0;
center = [1410, 2030];
span = [200, 200];
fraction = [0.1, 0.1];
pixel_size = 5.86e-6; % in meters
magnification = 23.94;
removeFringes = false;
ImagingMode = 'HighIntensity';
PulseDuration = 5e-6; % in s
% Fourier analysis settings
% Radial Spectral Distribution
theta_min = deg2rad(0);
theta_max = deg2rad(180);
N_radial_bins = 500;
Radial_Sigma = 2;
Radial_WindowSize = 5; % Choose an odd number for a centered moving average
% Angular Spectral Distribution
r_min = 10;
r_max = 20;
N_angular_bins = 180;
Angular_Threshold = 75;
Angular_Sigma = 2;
Angular_WindowSize = 5;
zoom_size = 50; % Zoomed-in region around center
% Plotting and saving
scan_parameter = 'ps_rot_mag_fin_pol_angle';
% scan_parameter = 'rot_mag_field';
savefileName = 'DropletsToStripes';
font = 'Bahnschrift';
if strcmp(savefileName, 'DropletsToStripes')
scan_groups = 0:5:45;
titleString = 'Droplets to Stripes';
elseif strcmp(savefileName, 'StripesToDroplets')
scan_groups = 45:-5:0;
titleString = 'Stripes to Droplets';
end
% Flags
skipNormalization = true;
skipUnshuffling = true;
skipPreprocessing = true;
skipMasking = true;
skipIntensityThresholding = true;
skipBinarization = true;
skipMovieRender = true;
skipSaveFigures = true;
skipSaveOD = true;
%% ===== S-D Settings =====
groupList = ["/images/MOT_3D_Camera/in_situ_absorption", "/images/ODT_1_Axis_Camera/in_situ_absorption", ...
"/images/ODT_2_Axis_Camera/in_situ_absorption", "/images/Horizontal_Axis_Camera/in_situ_absorption", ...
"/images/Vertical_Axis_Camera/in_situ_absorption"];
folderPath = "//DyLabNAS/Data/TwoDGas/2025/06/24/";
run = '0001';
folderPath = strcat(folderPath, run);
cam = 5;
angle = 0;
center = [1410, 2030];
span = [200, 200];
fraction = [0.1, 0.1];
pixel_size = 5.86e-6; % in meters
magnification = 23.94;
removeFringes = false;
ImagingMode = 'HighIntensity';
PulseDuration = 5e-6; % in s
% Fourier analysis settings
% Radial Spectral Distribution
theta_min = deg2rad(0);
theta_max = deg2rad(180);
N_radial_bins = 500;
Radial_Sigma = 2;
Radial_WindowSize = 5; % Choose an odd number for a centered moving average
% Angular Spectral Distribution
r_min = 10;
r_max = 20;
N_angular_bins = 180;
Angular_Threshold = 75;
Angular_Sigma = 2;
Angular_WindowSize = 5;
zoom_size = 50; % Zoomed-in region around center
% Plotting and saving
scan_parameter = 'ps_rot_mag_fin_pol_angle';
% scan_parameter = 'rot_mag_field';
savefileName = 'StripesToDroplets';
font = 'Bahnschrift';
if strcmp(savefileName, 'DropletsToStripes')
scan_groups = 0:5:45
titleString = 'Droplets to Stripes';
elseif strcmp(savefileName, 'StripesToDroplets')
scan_groups = 45:-5:0;
titleString = 'Stripes to Droplets';
end
% Flags
skipNormalization = true;
skipUnshuffling = false;
skipPreprocessing = true;
skipMasking = true;
skipIntensityThresholding = true;
skipBinarization = true;
skipMovieRender = true;
skipSaveFigures = true;
skipSaveOD = true;
%% ===== Load and compute OD image, rotate and extract ROI for analysis =====
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(folderPath, '*.h5');
files = dir(filePattern);
refimages = zeros(span(1) + 1, span(2) + 1, length(files));
absimages = zeros(span(1) + 1, span(2) + 1, length(files));
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
fprintf(1, 'Now reading %s\n', fullFileName);
atm_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/atoms")), angle));
bkg_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/background")), angle));
dark_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/dark")), angle));
if (isempty(atm_img) && isa(atm_img, 'double')) || ...
(isempty(bkg_img) && isa(bkg_img, 'double')) || ...
(isempty(dark_img) && isa(dark_img, 'double'))
refimages(:,:,k) = nan(size(refimages(:,:,k))); % fill with NaNs
absimages(:,:,k) = nan(size(absimages(:,:,k)));
else
refimages(:,:,k) = subtractBackgroundOffset(cropODImage(bkg_img, center, span), fraction)';
absimages(:,:,k) = subtractBackgroundOffset(cropODImage(calculateODImage(atm_img, bkg_img, dark_img, ImagingMode, PulseDuration), center, span), fraction)';
end
end
% ===== Fringe removal =====
if removeFringes
optrefimages = removefringesInImage(absimages, refimages);
absimages_fringe_removed = absimages(:, :, :) - optrefimages(:, :, :);
nimgs = size(absimages_fringe_removed,3);
od_imgs = cell(1, nimgs);
for i = 1:nimgs
od_imgs{i} = absimages_fringe_removed(:, :, i);
end
else
nimgs = size(absimages(:, :, :),3);
od_imgs = cell(1, nimgs);
for i = 1:nimgs
od_imgs{i} = absimages(:, :, i);
end
end
% ===== Get rotation angles =====
scan_parameter_values = zeros(1, length(files));
% Get information about the '/globals' group
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
info = h5info(fullFileName, '/globals');
for i = 1:length(info.Attributes)
if strcmp(info.Attributes(i).Name, scan_parameter)
if strcmp(scan_parameter, 'ps_rot_mag_fin_pol_angle')
scan_parameter_values(k) = 180 - info.Attributes(i).Value;
else
scan_parameter_values(k) = info.Attributes(i).Value;
end
end
end
end
% ===== Unshuffle if necessary to do so =====
if ~skipUnshuffling
n_values = length(scan_groups);
n_total = length(scan_parameter_values);
% Infer number of repetitions
n_reps = n_total / n_values;
% Preallocate ordered arrays
ordered_scan_values = zeros(1, n_total);
ordered_od_imgs = cell(1, n_total);
counter = 1;
for rep = 1:n_reps
for val = scan_groups
% Find the next unused match for this val
idx = find(scan_parameter_values == val, 1, 'first');
% Assign and remove from list to avoid duplicates
ordered_scan_values(counter) = scan_parameter_values(idx);
ordered_od_imgs{counter} = od_imgs{idx};
% Mark as used by removing
scan_parameter_values(idx) = NaN; % NaN is safe since original values are 0:5:45
od_imgs{idx} = []; % empty cell so it won't be matched again
counter = counter + 1;
end
end
% Now assign back
scan_parameter_values = ordered_scan_values;
od_imgs = ordered_od_imgs;
end
%% Carry out PCA
numPCs = 5;
% Stack all 600 images into one data matrix [nImages x nPixels]
allImgs3D = cat(3, od_imgs{:});
[Nx, Ny] = size(allImgs3D(:,:,1));
Xall = reshape(allImgs3D, [], numel(od_imgs))'; % [600 x (Nx*Ny)]
% Global PCA
[coeff, score, ~, ~, explained] = pca(Xall);
%% Visualize PC1
% Extract the first principal component vector (eigenimage)
pc1_vector = coeff(:,1);
% Reshape back to original image dimensions
pc1_image = reshape(pc1_vector, Nx, Ny);
% Plot the PC1 image
figure(1); clf; set(gcf, 'Color', 'w', 'Position', [100 100 950 750]);
imagesc(pc1_image);
axis image off;
colormap(Colormaps.coolwarm()); % or use 'jet', 'parula', etc.
colorbar;
title(sprintf('First Principal Component (PC1) Image - Explains %.2f%% Variance', explained(1)));
%% Distribution scatter plot
numGroups = numel(scan_groups);
colors = lines(numGroups);
figure(2); clf; set(gcf, 'Color', 'w', 'Position', [100 100 950 750]); hold on;
for g = 1:numGroups
idx = scan_parameter_values == scan_groups(g);
scatter(repmat(scan_groups(g), sum(idx),1), score(idx,1), 36, colors(g,:), 'filled');
end
xlabel('Control Parameter');
ylabel('PC1 Score');
title('Evolution of PC1 Scores');
grid on;
%% Distribution Histogram plot
numGroups = length(scan_groups);
colors = lines(numGroups);
% Define number of bins globally
numBins = 20;
% Define common bin edges based on global PC1 score range
minScore = min(score(:,1));
maxScore = max(score(:,1));
binEdges = linspace(minScore, maxScore, numBins+1); % +1 because edges are one more than bins
binWidth = binEdges(2) - binEdges(1); % for scaling KDE
figure(3);
clf; set(gcf, 'Color', 'w', 'Position', [100 100 950 750]);
tiledlayout(ceil(numGroups/2), 2, 'TileSpacing', 'compact', 'Padding', 'compact');
for g = 1:numGroups
groupVal = scan_groups(g);
idx = scan_parameter_values == groupVal;
groupPC1 = score(idx,1);
nexttile;
% Plot histogram
histogram(groupPC1, 'Normalization', 'probability', ...
'FaceColor', colors(g,:), 'EdgeColor', 'none', ...
'BinEdges', binEdges);
hold on;
% Compute KDE
[f, xi] = ksdensity(groupPC1, 'NumPoints', 1000);
% Scale KDE to histogram probability scale
f_scaled = f * binWidth;
% Overlay KDE curve
plot(xi, f_scaled, 'k', 'LineWidth', 1.5);
% Vertical line at median
med = median(groupPC1);
yl = ylim;
plot([med med], yl, 'k--', 'LineWidth', 1);
xlabel('PC1 Score');
ylabel('Probability');
title(sprintf('Control Parameter = %d', groupVal));
grid on;
hold off;
end
sgtitle('PC1 Score Distributions');
%% Box plot for PC1 scores by group
groupLabels = cell(size(score,1),1);
for g = 1:numGroups
idx = scan_parameter_values == scan_groups(g);
groupLabels(idx) = {sprintf('%d', scan_groups(g))};
end
figure(4);
clf; set(gcf, 'Color', 'w', 'Position', [100 100 950 750]);
boxplot(score(:,1), groupLabels);
xlabel('Control Parameter');
ylabel('PC1 Score');
title('Evolution of PC1 Scores');
grid on;
%% Mean and SEM plot for PC1 scores
numGroups = length(scan_groups);
meanPC1Scores = zeros(numGroups,1);
semPC1Scores = zeros(numGroups,1);
for g = 1:numGroups
groupVal = scan_groups(g);
idx = scan_parameter_values == groupVal;
groupPC1 = score(idx,1); % PC1 scores for this group
meanPC1Scores(g) = mean(groupPC1);
semPC1Scores(g) = std(groupPC1)/sqrt(sum(idx)); % Standard error of mean
end
% Plot mean ± SEM with error bars
figure(5);
clf; set(gcf, 'Color', 'w', 'Position', [100 100 950 750]);
errorbar(scan_groups, meanPC1Scores, semPC1Scores, 'o-', ...
'LineWidth', 1.5, 'MarkerSize', 8, 'MarkerFaceColor', 'b');
xlabel('Control Parameter');
ylabel('Mean PC1 Score ± SEM');
title('Evolution of PC1 Scores');
grid on;
%% Plot Binder Cumulant
maxOrder = 4; % We only need up to order 4 here
numGroups = length(scan_groups);
kappa4 = NaN(1, numGroups);
for g = 1:numGroups
groupVal = scan_groups(g);
idx = scan_parameter_values == groupVal;
groupPC1 = score(idx, 1);
cumulants = computeCumulants(groupPC1, maxOrder);
kappa4(g) = cumulants(4); % 4th-order cumulant
end
% Plot
figure(6);
clf; set(gcf, 'Color', 'w', 'Position', [100 100 950 750]);
plot(scan_groups, kappa4 * 1E-5, '-o', 'LineWidth', 1.5, 'MarkerFaceColor', 'b');
ylim([-12 12])
xlabel('Control Parameter');
ylabel('\kappa_4 (\times 10^{5})');
grid on;
title('Evolution of Binder Cumulant of PC1 Score');
%% --- ANOVA test ---
p = anova1(score(:,1), groupLabels, 'off');
fprintf('ANOVA p-value for PC1 score differences between groups: %.4e\n', p);
%% Helper Functions
function ret = getBkgOffsetFromCorners(img, x_fraction, y_fraction)
% image must be a 2D numerical array
[dim1, dim2] = size(img);
s1 = img(1:round(dim1 * y_fraction), 1:round(dim2 * x_fraction));
s2 = img(1:round(dim1 * y_fraction), round(dim2 - dim2 * x_fraction):dim2);
s3 = img(round(dim1 - dim1 * y_fraction):dim1, 1:round(dim2 * x_fraction));
s4 = img(round(dim1 - dim1 * y_fraction):dim1, round(dim2 - dim2 * x_fraction):dim2);
ret = mean([mean(s1(:)), mean(s2(:)), mean(s3(:)), mean(s4(:))]);
end
function ret = subtractBackgroundOffset(img, fraction)
% Remove the background from the image.
% :param dataArray: The image
% :type dataArray: xarray DataArray
% :param x_fraction: The fraction of the pixels used in x axis
% :type x_fraction: float
% :param y_fraction: The fraction of the pixels used in y axis
% :type y_fraction: float
% :return: The image after removing background
% :rtype: xarray DataArray
x_fraction = fraction(1);
y_fraction = fraction(2);
offset = getBkgOffsetFromCorners(img, x_fraction, y_fraction);
ret = img - offset;
end
function ret = cropODImage(img, center, span)
% Crop the image according to the region of interest (ROI).
% :param dataSet: The images
% :type dataSet: xarray DataArray or DataSet
% :param center: The center of region of interest (ROI)
% :type center: tuple
% :param span: The span of region of interest (ROI)
% :type span: tuple
% :return: The cropped images
% :rtype: xarray DataArray or DataSet
x_start = floor(center(1) - span(1) / 2);
x_end = floor(center(1) + span(1) / 2);
y_start = floor(center(2) - span(2) / 2);
y_end = floor(center(2) + span(2) / 2);
ret = img(y_start:y_end, x_start:x_end);
end
function imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%CALCULATEODIMAGE Calculates the optical density (OD) image for absorption imaging.
%
% imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%
% Inputs:
% imageAtom - Image with atoms
% imageBackground - Image without atoms
% imageDark - Image without light
% mode - 'LowIntensity' (default) or 'HighIntensity'
% exposureTime - Required only for 'HighIntensity' [in seconds]
%
% Output:
% imageOD - Computed OD image
%
arguments
imageAtom (:,:) {mustBeNumeric}
imageBackground (:,:) {mustBeNumeric}
imageDark (:,:) {mustBeNumeric}
mode char {mustBeMember(mode, {'LowIntensity', 'HighIntensity'})} = 'LowIntensity'
exposureTime double = NaN
end
% Compute numerator and denominator
numerator = imageBackground - imageDark;
denominator = imageAtom - imageDark;
% Avoid division by zero
numerator(numerator == 0) = 1;
denominator(denominator == 0) = 1;
% Calculate OD based on mode
switch mode
case 'LowIntensity'
imageOD = -log(abs(denominator ./ numerator));
case 'HighIntensity'
if isnan(exposureTime)
error('Exposure time must be provided for HighIntensity mode.');
end
imageOD = abs(denominator ./ numerator);
imageOD = -log(imageOD) + (numerator - denominator) ./ (7000 * (exposureTime / 5e-6));
end
end
function [optrefimages] = removefringesInImage(absimages, refimages, bgmask)
% removefringesInImage - Fringe removal and noise reduction from absorption images.
% Creates an optimal reference image for each absorption image in a set as
% a linear combination of reference images, with coefficients chosen to
% minimize the least-squares residuals between each absorption image and
% the optimal reference image. The coefficients are obtained by solving a
% linear set of equations using matrix inverse by LU decomposition.
%
% Application of the algorithm is described in C. F. Ockeloen et al, Improved
% detection of small atom numbers through image processing, arXiv:1007.2136 (2010).
%
% Syntax:
% [optrefimages] = removefringesInImage(absimages,refimages,bgmask);
%
% Required inputs:
% absimages - Absorption image data,
% typically 16 bit grayscale images
% refimages - Raw reference image data
% absimages and refimages are both cell arrays containing
% 2D array data. The number of refimages can differ from the
% number of absimages.
%
% Optional inputs:
% bgmask - Array specifying background region used,
% 1=background, 0=data. Defaults to all ones.
% Outputs:
% optrefimages - Cell array of optimal reference images,
% equal in size to absimages.
%
% Dependencies: none
%
% Authors: Shannon Whitlock, Caspar Ockeloen
% Reference: C. F. Ockeloen, A. F. Tauschinsky, R. J. C. Spreeuw, and
% S. Whitlock, Improved detection of small atom numbers through
% image processing, arXiv:1007.2136
% Email:
% May 2009; Last revision: 11 August 2010
% Process inputs
% Set variables, and flatten absorption and reference images
nimgs = size(absimages,3);
nimgsR = size(refimages,3);
xdim = size(absimages(:,:,1),2);
ydim = size(absimages(:,:,1),1);
R = single(reshape(refimages,xdim*ydim,nimgsR));
A = single(reshape(absimages,xdim*ydim,nimgs));
optrefimages=zeros(size(absimages)); % preallocate
if not(exist('bgmask','var')); bgmask=ones(ydim,xdim); end
k = find(bgmask(:)==1); % Index k specifying background region
% Ensure there are no duplicate reference images
% R=unique(R','rows')'; % comment this line if you run out of memory
% Decompose B = R*R' using singular value or LU decomposition
[L,U,p] = lu(R(k,:)'*R(k,:),'vector'); % LU decomposition
for j=1:nimgs
b=R(k,:)'*A(k,j);
% Obtain coefficients c which minimise least-square residuals
lower.LT = true; upper.UT = true;
c = linsolve(U,linsolve(L,b(p,:),lower),upper);
% Compute optimised reference image
optrefimages(:,:,j)=reshape(R*c,[ydim xdim]);
end
end

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function [cumulants_mean, cumulants_ci, bootstrap_samples] = bootstrapCumulants(x, maxOrder, nBoot)
% bootstrapCumulants - compute bootstrap estimates of cumulants and confidence intervals
%
% Syntax:
% [meanC, ciC, allC] = bootstrapCumulants(x, maxOrder, nBoot)
%
% Inputs:
% x - Data vector (may contain NaNs)
% maxOrder - Max cumulant order (default: 6)
% nBoot - Number of bootstrap samples (default: 1000)
%
% Outputs:
% cumulants_mean - Mean of bootstrap cumulants
% cumulants_ci - 95% confidence intervals [2.5th; 97.5th] percentile
% bootstrap_samples - All bootstrap cumulants (nBoot x maxOrder)
if nargin < 2, maxOrder = 6; end
if nargin < 3, nBoot = 1000; end
x = x(:);
x = x(~isnan(x)); % Remove NaNs
if isempty(x)
cumulants_mean = NaN(1, maxOrder);
cumulants_ci = NaN(2, maxOrder);
bootstrap_samples = NaN(nBoot, maxOrder);
return;
end
N = numel(x);
bootstrap_samples = zeros(nBoot, maxOrder);
for b = 1:nBoot
xb = x(randi(N, [N, 1])); % Resample with replacement
bootstrap_samples(b, :) = computeCumulants(xb, maxOrder);
end
cumulants_mean = mean(bootstrap_samples, 1);
cumulants_ci = prctile(bootstrap_samples, [2.5, 97.5]);
end

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%% Track spectral weight across the transition
set(0,'defaulttextInterpreter','latex')
set(groot, 'defaultAxesTickLabelInterpreter','latex'); set(groot, 'defaultLegendInterpreter','latex');
format long
font = 'Bahnschrift';
% Load data
Data = load('C:/Users/Karthik/Documents/GitRepositories/Calculations/Data-Analyzer/StructuralPhaseTransition/SpectralAnalysisRoutines/Max_g2_DropletsToStripes.mat', 'unique_scan_parameter_values', 'mean_max_g2_values', 'std_error_g2_values');
dts_scan_parameter_values = Data.unique_scan_parameter_values;
dts_mean_mg2 = Data.mean_max_g2_values;
dts_stderr_mg2 = Data.std_error_g2_values;
Data = load('C:/Users/Karthik/Documents/GitRepositories/Calculations/Data-Analyzer/StructuralPhaseTransition/SpectralAnalysisRoutines/Max_g2_StripesToDroplets.mat', 'unique_scan_parameter_values', 'mean_max_g2_values', 'std_error_g2_values');
std_scan_parameter_values = Data.unique_scan_parameter_values;
std_mean_mg2 = Data.mean_max_g2_values;
std_stderr_mg2 = Data.std_error_g2_values;
figure(1);
set(gcf,'Position',[100 100 950 750])
errorbar(dts_scan_parameter_values, dts_mean_mg2, dts_stderr_mg2, 'o--', ...
'LineWidth', 1.5, 'MarkerSize', 6, 'CapSize', 5, 'DisplayName' , 'Droplets to Stripes');
hold on
errorbar(std_scan_parameter_values, std_mean_mg2, std_stderr_mg2, 'o--', ...
'LineWidth', 1.5, 'MarkerSize', 6, 'CapSize', 5, 'DisplayName', 'Stripes to Droplets');
set(gca, 'FontSize', 14, 'YLim', [0, 1]);
hXLabel = xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex');
hYLabel = ylabel('$\mathrm{max}[g^{(2)}_{[50,70]}(\delta\theta)]$', 'Interpreter', 'latex');
% hTitle = title('B = 2.42 G', 'Interpreter', 'tex');
legend
set([hXLabel, hYLabel], 'FontName', font)
set([hXLabel, hYLabel], 'FontSize', 14)
% set(hTitle, 'FontName', font, 'FontSize', 16, 'FontWeight', 'bold'); % Set font and size for title
grid on
%%

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function cumulants = computeCumulants(x, maxOrder)
% computeCumulants - compute cumulants up to specified order from data vector x
%
% Syntax: cumulants = computeCumulants(x, maxOrder)
%
% Inputs:
% x - 1D numeric vector (may contain NaNs)
% maxOrder - maximum order of cumulants to compute (default: 6)
%
% Output:
% cumulants - vector [kappa_1, ..., kappa_maxOrder]
if nargin < 2
maxOrder = 6;
end
x = x(:);
x = x(~isnan(x)); % Remove NaNs
if isempty(x)
cumulants = NaN(1, maxOrder);
return;
end
mu1 = mean(x, 'omitnan');
x_centered = x - mu1;
cumulants = zeros(1, maxOrder);
cumulants(1) = mu1;
mu = zeros(1, maxOrder);
for k = 2:maxOrder
mu(k) = mean(x_centered.^k, 'omitnan');
end
if maxOrder >= 2
cumulants(2) = mu(2);
end
if maxOrder >= 3
cumulants(3) = mu(3);
end
if maxOrder >= 4
cumulants(4) = mu(4) - 3 * mu(2)^2;
end
if maxOrder >= 5
cumulants(5) = mu(5) - 10 * mu(3) * mu(2);
end
if maxOrder >= 6
cumulants(6) = mu(6) - 15 * mu(4) * mu(2) - 10 * mu(3)^2 + 30 * mu(2)^3;
end
end

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%% ===== Settings =====
groupList = ["/images/MOT_3D_Camera/in_situ_absorption", "/images/ODT_1_Axis_Camera/in_situ_absorption", ...
"/images/ODT_2_Axis_Camera/in_situ_absorption", "/images/Horizontal_Axis_Camera/in_situ_absorption", ...
"/images/Vertical_Axis_Camera/in_situ_absorption"];
folderPath = "//DyLabNAS/Data/TwoDGas/2025/06/23/";
run = '0300';
folderPath = strcat(folderPath, run);
cam = 5;
angle = 0;
center = [1410, 2030];
span = [200, 200];
fraction = [0.1, 0.1];
pixel_size = 5.86e-6; % in meters
magnification = 23.94;
removeFringes = false;
ImagingMode = 'HighIntensity';
PulseDuration = 5e-6; % in s
% Fourier analysis settings
% Radial Spectral Distribution
theta_min = deg2rad(0);
theta_max = deg2rad(180);
N_radial_bins = 500;
Radial_Sigma = 2;
Radial_WindowSize = 5; % Choose an odd number for a centered moving average
% Angular Spectral Distribution
r_min = 10;
r_max = 20;
N_angular_bins = 180;
Angular_Threshold = 75;
Angular_Sigma = 2;
Angular_WindowSize = 5;
zoom_size = 50; % Zoomed-in region around center
% Plotting and saving
scan_parameter = 'ps_rot_mag_fin_pol_angle';
% scan_parameter = 'rot_mag_field';
scan_parameter_text = 'Angle = ';
% scan_parameter_text = 'BField = ';
savefileName = 'DropletsToStripes';
font = 'Bahnschrift';
if strcmp(savefileName, 'DropletsToStripes')
scan_groups = 0:5:45;
titleString = 'Droplets to Stripes';
elseif strcmp(savefileName, 'StripesToDroplets')
scan_groups = 45:-5:0;
titleString = 'Stripes to Droplets';
end
% Flags
skipUnshuffling = true;
skipPreprocessing = true;
skipMasking = true;
skipIntensityThresholding = true;
skipBinarization = true;
skipMovieRender = true;
skipSaveFigures = true;
%% ===== Load and compute OD image, rotate and extract ROI for analysis =====
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(folderPath, '*.h5');
files = dir(filePattern);
refimages = zeros(span(1) + 1, span(2) + 1, length(files));
absimages = zeros(span(1) + 1, span(2) + 1, length(files));
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
fprintf(1, 'Now reading %s\n', fullFileName);
atm_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/atoms")), angle));
bkg_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/background")), angle));
dark_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/dark")), angle));
if (isempty(atm_img) && isa(atm_img, 'double')) || ...
(isempty(bkg_img) && isa(bkg_img, 'double')) || ...
(isempty(dark_img) && isa(dark_img, 'double'))
refimages(:,:,k) = nan(size(refimages(:,:,k))); % fill with NaNs
absimages(:,:,k) = nan(size(absimages(:,:,k)));
else
refimages(:,:,k) = subtractBackgroundOffset(cropODImage(bkg_img, center, span), fraction)';
absimages(:,:,k) = subtractBackgroundOffset(cropODImage(calculateODImage(atm_img, bkg_img, dark_img, ImagingMode, PulseDuration), center, span), fraction)';
end
end
%% ===== Fringe removal =====
if removeFringes
optrefimages = removefringesInImage(absimages, refimages);
absimages_fringe_removed = absimages(:, :, :) - optrefimages(:, :, :);
nimgs = size(absimages_fringe_removed,3);
od_imgs = cell(1, nimgs);
for i = 1:nimgs
od_imgs{i} = absimages_fringe_removed(:, :, i);
end
else
nimgs = size(absimages(:, :, :),3);
od_imgs = cell(1, nimgs);
for i = 1:nimgs
od_imgs{i} = absimages(:, :, i);
end
end
%% ===== Get rotation angles =====
scan_parameter_values = zeros(1, length(files));
% Get information about the '/globals' group
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
info = h5info(fullFileName, '/globals');
for i = 1:length(info.Attributes)
if strcmp(info.Attributes(i).Name, scan_parameter)
if strcmp(scan_parameter, 'ps_rot_mag_fin_pol_angle')
scan_parameter_values(k) = 180 - info.Attributes(i).Value;
else
scan_parameter_values(k) = info.Attributes(i).Value;
end
end
end
end
%% ===== Extract g2 from experiment data =====
fft_imgs = cell(1, nimgs);
spectral_distribution = cell(1, nimgs);
theta_values = cell(1, nimgs);
N_shots = length(od_imgs);
% Compute FFT
for k = 1:N_shots
IMG = od_imgs{k};
[IMGFFT, IMGPR] = computeFourierTransform(IMG, skipPreprocessing, skipMasking, skipIntensityThresholding, skipBinarization);
% Size of original image (in pixels)
[Ny, Nx] = size(IMG);
% Real-space pixel size in micrometers after magnification
dx = pixel_size / magnification;
dy = dx; % assuming square pixels
% Real-space axes
x = ((1:Nx) - ceil(Nx/2)) * dx * 1E6;
y = ((1:Ny) - ceil(Ny/2)) * dy * 1E6;
% Reciprocal space increments (frequency domain, μm¹)
dvx = 1 / (Nx * dx);
dvy = 1 / (Ny * dy);
% Frequency axes
vx = (-floor(Nx/2):ceil(Nx/2)-1) * dvx;
vy = (-floor(Ny/2):ceil(Ny/2)-1) * dvy;
% Wavenumber axes
kx_full = 2 * pi * vx * 1E-6; % μm¹
ky_full = 2 * pi * vy * 1E-6;
% Crop FFT image around center
mid_x = floor(Nx/2);
mid_y = floor(Ny/2);
fft_imgs{k} = IMGFFT(mid_y-zoom_size:mid_y+zoom_size, mid_x-zoom_size:mid_x+zoom_size);
% Crop wavenumber axes to match fft_imgs{k}
kx = kx_full(mid_x - zoom_size : mid_x + zoom_size);
ky = ky_full(mid_y - zoom_size : mid_y + zoom_size);
[theta_values, S_theta] = computeAngularSpectralDistribution(fft_imgs{k}, r_min, r_max, N_angular_bins, Angular_Threshold, Angular_Sigma, []);
spectral_distribution{k} = S_theta;
end
% Create matrix of shape (N_shots x N_angular_bins)
delta_nkr_all = zeros(N_shots, N_angular_bins);
for k = 1:N_shots
delta_nkr_all(k, :) = spectral_distribution{k};
end
% Grouping by scan parameter value (e.g., alpha)
[unique_scan_parameter_values, ~, idx] = unique(scan_parameter_values);
% Number of unique parameter values
N_params = length(unique_scan_parameter_values);
% Preallocate result arrays
g2_all = zeros(N_params, N_angular_bins);
g2_error_all = zeros(N_params, N_angular_bins);
% Compute g2
for i = 1:N_params
group_idx = find(idx == i);
group_data = delta_nkr_all(group_idx, :);
for dtheta = 0:N_angular_bins-1
temp = zeros(length(group_idx), 1);
for j = 1:length(group_idx)
profile = group_data(j, :);
profile_shifted = circshift(profile, -dtheta, 2);
num = mean(profile .* profile_shifted);
denom = mean(profile.^2);
temp(j) = num / denom;
end
g2_all(i, dtheta+1) = mean(temp, 'omitnan');
g2_error_all(i, dtheta+1) = std(temp, 'omitnan') / sqrt(length(group_idx)); % Standard error
end
end
% Number of unique parameter values
nParams = size(g2_all, 1);
% Generate a colormap with enough unique colors
cmap = sky(nParams); % You can also try 'jet', 'turbo', 'hot', etc.
figure(1);
clf;
set(gcf, 'Color', 'w', 'Position',[100 100 950 750])
hold on;
legend_entries = cell(nParams, 1);
for i = 1:nParams
errorbar(theta_values/pi, g2_all(i, :), g2_error_all(i, :), ...
'o', 'Color', cmap(i,:), ...
'MarkerSize', 3, 'MarkerFaceColor', cmap(i,:), ...
'CapSize', 4);
if strcmp(scan_parameter, 'ps_rot_mag_fin_pol_angle')
legend_entries{i} = sprintf('$\\alpha = %g^\\circ$', unique_scan_parameter_values(i));
elseif strcmp(scan_parameter, 'rot_mag_field')
legend_entries{i} = sprintf('B = %.2f G', unique_scan_parameter_values(i));
end
end
ylim([0.0 1.0]); % Set y-axis limits here
set(gca, 'FontSize', 14);
hXLabel = xlabel('$\delta\theta / \pi$', 'Interpreter', 'latex');
hYLabel = ylabel('$g^{(2)}(\delta\theta)$', 'Interpreter', 'latex');
hTitle = title(titleString, 'Interpreter', 'tex');
legend(legend_entries, 'Interpreter', 'latex', 'Location', 'bestoutside');
set([hXLabel, hYLabel], 'FontName', font)
set([hXLabel, hYLabel], 'FontSize', 14)
set(hTitle, 'FontName', font, 'FontSize', 16, 'FontWeight', 'bold'); % Set font and size for title
grid on;
%% Helper Functions
function [IMGFFT, IMGPR] = computeFourierTransform(I, skipPreprocessing, skipMasking, skipIntensityThresholding, skipBinarization)
% computeFourierSpectrum - Computes the 2D Fourier power spectrum
% of binarized and enhanced lattice image features, with optional central mask.
%
% Inputs:
% I - Grayscale or RGB image matrix
%
% Output:
% F_mag - 2D Fourier power spectrum (shifted)
if ~skipPreprocessing
% Preprocessing: Denoise
filtered = imgaussfilt(I, 10);
IMGPR = I - filtered; % adjust sigma as needed
else
IMGPR = I;
end
if ~skipMasking
[rows, cols] = size(IMGPR);
[X, Y] = meshgrid(1:cols, 1:rows);
% Elliptical mask parameters
cx = cols / 2;
cy = rows / 2;
% Shifted coordinates
x = X - cx;
y = Y - cy;
% Ellipse semi-axes
rx = 0.4 * cols;
ry = 0.2 * rows;
% Rotation angle in degrees -> radians
theta_deg = 30; % Adjust as needed
theta = deg2rad(theta_deg);
% Rotated ellipse equation
cos_t = cos(theta);
sin_t = sin(theta);
x_rot = (x * cos_t + y * sin_t);
y_rot = (-x * sin_t + y * cos_t);
ellipseMask = (x_rot.^2) / rx^2 + (y_rot.^2) / ry^2 <= 1;
% Apply cutout mask
IMGPR = IMGPR .* ellipseMask;
end
if ~skipIntensityThresholding
% Apply global intensity threshold mask
intensity_thresh = 0.20;
intensity_mask = IMGPR > intensity_thresh;
IMGPR = IMGPR .* intensity_mask;
end
if ~skipBinarization
% Adaptive binarization and cleanup
IMGPR = imbinarize(IMGPR, 'adaptive', 'Sensitivity', 0.0);
IMGPR = imdilate(IMGPR, strel('disk', 2));
IMGPR = imerode(IMGPR, strel('disk', 1));
IMGPR = imfill(IMGPR, 'holes');
F = fft2(double(IMGPR)); % Compute 2D Fourier Transform
IMGFFT = abs(fftshift(F))'; % Shift zero frequency to center
else
F = fft2(double(IMGPR)); % Compute 2D Fourier Transform
IMGFFT = abs(fftshift(F))'; % Shift zero frequency to center
end
end
function [theta_vals, S_theta] = computeAngularSpectralDistribution(IMGFFT, r_min, r_max, num_bins, threshold, sigma, windowSize)
% Apply threshold to isolate strong peaks
IMGFFT(IMGFFT < threshold) = 0;
% Prepare polar coordinates
[ny, nx] = size(IMGFFT);
[X, Y] = meshgrid(1:nx, 1:ny);
cx = ceil(nx/2);
cy = ceil(ny/2);
R = sqrt((X - cx).^2 + (Y - cy).^2);
Theta = atan2(Y - cy, X - cx); % range [-pi, pi]
% Choose radial band
radial_mask = (R >= r_min) & (R <= r_max);
% Initialize angular structure factor
S_theta = zeros(1, num_bins);
theta_vals = linspace(0, pi, num_bins);
% Loop through angle bins
for i = 1:num_bins
angle_start = (i-1) * pi / num_bins;
angle_end = i * pi / num_bins;
angle_mask = (Theta >= angle_start & Theta < angle_end);
bin_mask = radial_mask & angle_mask;
fft_angle = IMGFFT .* bin_mask;
S_theta(i) = sum(sum(abs(fft_angle).^2));
end
% Smooth using either Gaussian or moving average
if exist('sigma', 'var') && ~isempty(sigma)
% Gaussian convolution
half_width = ceil(3 * sigma);
x = -half_width:half_width;
gauss_kernel = exp(-x.^2 / (2 * sigma^2));
gauss_kernel = gauss_kernel / sum(gauss_kernel);
% Circular convolution
S_theta = conv([S_theta(end-half_width+1:end), S_theta, S_theta(1:half_width)], ...
gauss_kernel, 'same');
S_theta = S_theta(half_width+1:end-half_width);
elseif exist('windowSize', 'var') && ~isempty(windowSize)
% Moving average via convolution (circular)
pad = floor(windowSize / 2);
kernel = ones(1, windowSize) / windowSize;
S_theta = conv([S_theta(end-pad+1:end), S_theta, S_theta(1:pad)], kernel, 'same');
S_theta = S_theta(pad+1:end-pad);
end
end
function ret = getBkgOffsetFromCorners(img, x_fraction, y_fraction)
% image must be a 2D numerical array
[dim1, dim2] = size(img);
s1 = img(1:round(dim1 * y_fraction), 1:round(dim2 * x_fraction));
s2 = img(1:round(dim1 * y_fraction), round(dim2 - dim2 * x_fraction):dim2);
s3 = img(round(dim1 - dim1 * y_fraction):dim1, 1:round(dim2 * x_fraction));
s4 = img(round(dim1 - dim1 * y_fraction):dim1, round(dim2 - dim2 * x_fraction):dim2);
ret = mean([mean(s1(:)), mean(s2(:)), mean(s3(:)), mean(s4(:))]);
end
function ret = subtractBackgroundOffset(img, fraction)
% Remove the background from the image.
% :param dataArray: The image
% :type dataArray: xarray DataArray
% :param x_fraction: The fraction of the pixels used in x axis
% :type x_fraction: float
% :param y_fraction: The fraction of the pixels used in y axis
% :type y_fraction: float
% :return: The image after removing background
% :rtype: xarray DataArray
x_fraction = fraction(1);
y_fraction = fraction(2);
offset = getBkgOffsetFromCorners(img, x_fraction, y_fraction);
ret = img - offset;
end
function ret = cropODImage(img, center, span)
% Crop the image according to the region of interest (ROI).
% :param dataSet: The images
% :type dataSet: xarray DataArray or DataSet
% :param center: The center of region of interest (ROI)
% :type center: tuple
% :param span: The span of region of interest (ROI)
% :type span: tuple
% :return: The cropped images
% :rtype: xarray DataArray or DataSet
x_start = floor(center(1) - span(1) / 2);
x_end = floor(center(1) + span(1) / 2);
y_start = floor(center(2) - span(2) / 2);
y_end = floor(center(2) + span(2) / 2);
ret = img(y_start:y_end, x_start:x_end);
end
function imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%CALCULATEODIMAGE Calculates the optical density (OD) image for absorption imaging.
%
% imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%
% Inputs:
% imageAtom - Image with atoms
% imageBackground - Image without atoms
% imageDark - Image without light
% mode - 'LowIntensity' (default) or 'HighIntensity'
% exposureTime - Required only for 'HighIntensity' [in seconds]
%
% Output:
% imageOD - Computed OD image
%
arguments
imageAtom (:,:) {mustBeNumeric}
imageBackground (:,:) {mustBeNumeric}
imageDark (:,:) {mustBeNumeric}
mode char {mustBeMember(mode, {'LowIntensity', 'HighIntensity'})} = 'LowIntensity'
exposureTime double = NaN
end
% Compute numerator and denominator
numerator = imageBackground - imageDark;
denominator = imageAtom - imageDark;
% Avoid division by zero
numerator(numerator == 0) = 1;
denominator(denominator == 0) = 1;
% Calculate OD based on mode
switch mode
case 'LowIntensity'
imageOD = -log(abs(denominator ./ numerator));
case 'HighIntensity'
if isnan(exposureTime)
error('Exposure time must be provided for HighIntensity mode.');
end
imageOD = abs(denominator ./ numerator);
imageOD = -log(imageOD) + (numerator - denominator) ./ (7000 * (exposureTime / 5e-6));
end
end
function [optrefimages] = removefringesInImage(absimages, refimages, bgmask)
% removefringesInImage - Fringe removal and noise reduction from absorption images.
% Creates an optimal reference image for each absorption image in a set as
% a linear combination of reference images, with coefficients chosen to
% minimize the least-squares residuals between each absorption image and
% the optimal reference image. The coefficients are obtained by solving a
% linear set of equations using matrix inverse by LU decomposition.
%
% Application of the algorithm is described in C. F. Ockeloen et al, Improved
% detection of small atom numbers through image processing, arXiv:1007.2136 (2010).
%
% Syntax:
% [optrefimages] = removefringesInImage(absimages,refimages,bgmask);
%
% Required inputs:
% absimages - Absorption image data,
% typically 16 bit grayscale images
% refimages - Raw reference image data
% absimages and refimages are both cell arrays containing
% 2D array data. The number of refimages can differ from the
% number of absimages.
%
% Optional inputs:
% bgmask - Array specifying background region used,
% 1=background, 0=data. Defaults to all ones.
% Outputs:
% optrefimages - Cell array of optimal reference images,
% equal in size to absimages.
%
% Dependencies: none
%
% Authors: Shannon Whitlock, Caspar Ockeloen
% Reference: C. F. Ockeloen, A. F. Tauschinsky, R. J. C. Spreeuw, and
% S. Whitlock, Improved detection of small atom numbers through
% image processing, arXiv:1007.2136
% Email:
% May 2009; Last revision: 11 August 2010
% Process inputs
% Set variables, and flatten absorption and reference images
nimgs = size(absimages,3);
nimgsR = size(refimages,3);
xdim = size(absimages(:,:,1),2);
ydim = size(absimages(:,:,1),1);
R = single(reshape(refimages,xdim*ydim,nimgsR));
A = single(reshape(absimages,xdim*ydim,nimgs));
optrefimages=zeros(size(absimages)); % preallocate
if not(exist('bgmask','var')); bgmask=ones(ydim,xdim); end
k = find(bgmask(:)==1); % Index k specifying background region
% Ensure there are no duplicate reference images
% R=unique(R','rows')'; % comment this line if you run out of memory
% Decompose B = R*R' using singular value or LU decomposition
[L,U,p] = lu(R(k,:)'*R(k,:),'vector'); % LU decomposition
for j=1:nimgs
b=R(k,:)'*A(k,j);
% Obtain coefficients c which minimise least-square residuals
lower.LT = true; upper.UT = true;
c = linsolve(U,linsolve(L,b(p,:),lower),upper);
% Compute optimised reference image
optrefimages(:,:,j)=reshape(R*c,[ydim xdim]);
end
end

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@ -0,0 +1,738 @@
%% ===== D-S Settings =====
groupList = ["/images/MOT_3D_Camera/in_situ_absorption", "/images/ODT_1_Axis_Camera/in_situ_absorption", ...
"/images/ODT_2_Axis_Camera/in_situ_absorption", "/images/Horizontal_Axis_Camera/in_situ_absorption", ...
"/images/Vertical_Axis_Camera/in_situ_absorption"];
folderPath = "//DyLabNAS/Data/TwoDGas/2025/07/22/";
run = '0021';
folderPath = strcat(folderPath, run);
cam = 5;
angle = 0;
center = [1410, 2030];
span = [200, 200];
fraction = [0.1, 0.1];
pixel_size = 5.86e-6; % in meters
magnification = 23.94;
removeFringes = false;
ImagingMode = 'HighIntensity';
PulseDuration = 5e-6; % in s
% Fourier analysis settings
% Radial Spectral Distribution
theta_min = deg2rad(0);
theta_max = deg2rad(180);
N_radial_bins = 500;
Radial_Sigma = 2;
Radial_WindowSize = 5; % Choose an odd number for a centered moving average
% Angular Spectral Distribution
r_min = 10;
r_max = 20;
N_angular_bins = 180;
Angular_Threshold = 75;
Angular_Sigma = 2;
Angular_WindowSize = 5;
zoom_size = 50; % Zoomed-in region around center
% Plotting and saving
scan_parameter = 'ps_rot_mag_fin_pol_angle';
% scan_parameter = 'rot_mag_field';
savefileName = 'DropletsToStripes';
font = 'Bahnschrift';
if strcmp(savefileName, 'DropletsToStripes')
scan_groups = 0:1:40;
titleString = 'Droplets to Stripes';
elseif strcmp(savefileName, 'StripesToDroplets')
scan_groups = 40:-1:0;
titleString = 'Stripes to Droplets';
end
% Flags
skipNormalization = true;
skipUnshuffling = false;
skipPreprocessing = true;
skipMasking = true;
skipIntensityThresholding = true;
skipBinarization = true;
skipMovieRender = true;
skipSaveFigures = false;
skipSaveOD = true;
%% ===== Load and compute OD image, rotate and extract ROI for analysis =====
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(folderPath, '*.h5');
files = dir(filePattern);
refimages = zeros(span(1) + 1, span(2) + 1, length(files));
absimages = zeros(span(1) + 1, span(2) + 1, length(files));
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
fprintf(1, 'Now reading %s\n', fullFileName);
atm_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/atoms")), angle));
bkg_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/background")), angle));
dark_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/dark")), angle));
if (isempty(atm_img) && isa(atm_img, 'double')) || ...
(isempty(bkg_img) && isa(bkg_img, 'double')) || ...
(isempty(dark_img) && isa(dark_img, 'double'))
refimages(:,:,k) = nan(size(refimages(:,:,k))); % fill with NaNs
absimages(:,:,k) = nan(size(absimages(:,:,k)));
else
refimages(:,:,k) = subtractBackgroundOffset(cropODImage(bkg_img, center, span), fraction)';
absimages(:,:,k) = subtractBackgroundOffset(cropODImage(calculateODImage(atm_img, bkg_img, dark_img, ImagingMode, PulseDuration), center, span), fraction)';
end
end
% ===== Fringe removal =====
if removeFringes
optrefimages = removefringesInImage(absimages, refimages);
absimages_fringe_removed = absimages(:, :, :) - optrefimages(:, :, :);
nimgs = size(absimages_fringe_removed,3);
od_imgs = cell(1, nimgs);
for i = 1:nimgs
od_imgs{i} = absimages_fringe_removed(:, :, i);
end
else
nimgs = size(absimages(:, :, :),3);
od_imgs = cell(1, nimgs);
for i = 1:nimgs
od_imgs{i} = absimages(:, :, i);
end
end
%% ===== Get rotation angles =====
scan_parameter_values = zeros(1, length(files));
% Get information about the '/globals' group
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
info = h5info(fullFileName, '/globals');
for i = 1:length(info.Attributes)
if strcmp(info.Attributes(i).Name, scan_parameter)
if strcmp(scan_parameter, 'ps_rot_mag_fin_pol_angle')
scan_parameter_values(k) = 180 - info.Attributes(i).Value;
else
scan_parameter_values(k) = info.Attributes(i).Value;
end
end
end
end
%% ===== Correlation of a single (highest) peak with a possible peak between 50-70 degrees from experiment data =====
fft_imgs = cell(1, nimgs);
spectral_distribution = cell(1, nimgs);
theta_values = cell(1, nimgs);
N_shots = length(od_imgs);
% Compute FFT for all images
for k = 1:N_shots
IMG = od_imgs{k};
[IMGFFT, IMGPR] = computeFourierTransform(IMG, skipPreprocessing, skipMasking, skipIntensityThresholding, skipBinarization);
[Ny, Nx] = size(IMG);
dx = pixel_size / magnification;
dy = dx; % assuming square pixels
x = ((1:Nx) - ceil(Nx/2)) * dx * 1E6;
y = ((1:Ny) - ceil(Ny/2)) * dy * 1E6;
dvx = 1 / (Nx * dx);
dvy = 1 / (Ny * dy);
vx = (-floor(Nx/2):ceil(Nx/2)-1) * dvx;
vy = (-floor(Ny/2):ceil(Ny/2)-1) * dvy;
kx_full = 2 * pi * vx * 1E-6;
ky_full = 2 * pi * vy * 1E-6;
mid_x = floor(Nx/2);
mid_y = floor(Ny/2);
fft_imgs{k} = IMGFFT(mid_y-zoom_size:mid_y+zoom_size, mid_x-zoom_size:mid_x+zoom_size);
kx = kx_full(mid_x - zoom_size : mid_x + zoom_size);
ky = ky_full(mid_y - zoom_size : mid_y + zoom_size);
[theta_vals, S_theta] = computeAngularSpectralDistribution(fft_imgs{k}, r_min, r_max, N_angular_bins, Angular_Threshold, Angular_Sigma, []);
spectral_distribution{k} = S_theta;
theta_values{k} = theta_vals;
end
% Convert spectral distribution to matrix (N_shots x N_angular_bins)
delta_nkr_all = zeros(N_shots, N_angular_bins);
for k = 1:N_shots
delta_nkr_all(k, :) = spectral_distribution{k};
end
% Group by scan parameter values (e.g., alpha, angle, etc.)
[unique_scan_parameter_values, ~, idx] = unique(scan_parameter_values);
N_params = length(unique_scan_parameter_values);
% Define angular range and conversion
angle_range = 180;
angle_per_bin = angle_range / N_angular_bins;
max_peak_angle = 180;
max_peak_bin = round(max_peak_angle / angle_per_bin);
% Parameters for search
window_size = 10;
angle_threshold = 100;
% Initialize containers for final results
mean_max_g2_values = zeros(1, N_params);
skew_max_g2_angle_values = zeros(1, N_params);
var_max_g2_values = zeros(1, N_params);
fourth_order_cumulant_max_g2_angle_values= zeros(1, N_params);
fifth_order_cumulant_max_g2_angle_values = zeros(1, N_params);
sixth_order_cumulant_max_g2_angle_values = zeros(1, N_params);
% Also store raw data per group
max_g2_all_per_group = cell(1, N_params);
std_error_g2_values = zeros(1, N_params);
for i = 1:N_params
group_idx = find(idx == i);
group_data = delta_nkr_all(group_idx, :);
N_reps = size(group_data, 1);
g2_values = zeros(1, N_reps);
for j = 1:N_reps
profile = group_data(j, :);
% Restrict search to 060° for highest peak
restricted_profile = profile(1:max_peak_bin);
[~, peak_idx_rel] = max(restricted_profile);
peak_idx = peak_idx_rel;
peak_angle = (peak_idx - 1) * angle_per_bin;
if peak_angle < angle_threshold
offsets = round(50 / angle_per_bin) : round(70 / angle_per_bin);
else
offsets = -round(70 / angle_per_bin) : -round(50 / angle_per_bin);
end
ref_window = mod((peak_idx - window_size):(peak_idx + window_size) - 1, N_angular_bins) + 1;
ref = profile(ref_window);
correlations = zeros(size(offsets));
for k = 1:length(offsets)
shifted_idx = mod(peak_idx + offsets(k) - 1, N_angular_bins) + 1;
sec_window = mod((shifted_idx - window_size):(shifted_idx + window_size) - 1, N_angular_bins) + 1;
sec = profile(sec_window);
num = mean(ref .* sec);
denom = mean(ref.^2);
g2 = num / denom;
correlations(k) = g2;
end
[max_corr, max_idx] = max(correlations);
g2_values(j) = max_corr;
end
% Store raw values
max_g2_all_per_group{i} = g2_values;
% Compute cumulants
kappa = computeCumulants(g2_values(:), 6);
% Final stats
mean_max_g2_values(i) = kappa(1);
var_max_g2_values(i) = kappa(2);
N_eff = sum(~isnan(g2_values));
std_error_g2_values(i) = sqrt(kappa(2)) / sqrt(N_eff);
skew_max_g2_angle_values(i) = kappa(3);
fourth_order_cumulant_max_g2_angle_values(i)= kappa(4);
fifth_order_cumulant_max_g2_angle_values(i) = kappa(5);
sixth_order_cumulant_max_g2_angle_values(i) = kappa(6);
end
%% Plot PDF of order parameter
if ~skipSaveFigures
% Define folder for saving images
saveFolder = [savefileName '_SavedFigures'];
if ~exist(saveFolder, 'dir')
mkdir(saveFolder);
end
end
figure(2); % one persistent figure
set(gcf, 'Color', 'w', 'Position', [100 100 950 750])
for val = scan_groups
% Find the index i that matches this scan parameter value
i = find(unique_scan_parameter_values == val, 1);
% Skip if not found (sanity check)
if isempty(i)
continue;
end
g2_vals = max_g2_all_per_group{i};
g2_vals = g2_vals(~isnan(g2_vals));
if isempty(g2_vals)
continue;
end
% KDE estimation
[f, xi] = ksdensity(g2_vals, 'NumPoints', 200);
clf;
histogram(g2_vals, 'Normalization', 'pdf', ...
'NumBins', 10, ...
'FaceAlpha', 0.3, ...
'EdgeColor', 'none', ...
'FaceColor', [0.3 0.5 0.8]);
hold on;
plot(xi, f, 'LineWidth', 2, 'Color', [0 0.2 0.6]);
set(gca, 'FontSize', 16);
title(sprintf('%s: \\boldmath$\\alpha = %.1f^{\\circ}$', titleString, val), ...
'FontSize', 16, 'Interpreter', 'latex');
xlabel('$\mathrm{max}[g^{(2)}_{[50,70]}(\delta\theta)]$', 'Interpreter', 'latex', 'FontSize', 14);
ylabel('PDF', 'FontSize', 14);
xlim([0.0, 1.5]);
grid on;
drawnow;
% ==== Save Figure ====
if ~skipSaveFigures
% Create a filename for each averaged plot
fileNamePNG = fullfile(saveFolder, sprintf('max_g2_analysis_param_%03d.png', val));
% Save current figure as PNG with high resolution
print(gcf, fileNamePNG, '-dpng', '-r300'); % 300 dpi for high quality
else
pause(0.5)
end
end
%% Plot all cumulants
figure(3)
set(gcf, 'Color', 'w', 'Position', [100 100 950 750])
scan_vals = unique_scan_parameter_values;
% Define font style for consistency
axis_fontsize = 14;
label_fontsize = 16;
title_fontsize = 16;
% 1. Mean with error bars
subplot(3,2,1);
errorbar(scan_vals, mean_max_g2_values, std_error_g2_values, 'o-', ...
'LineWidth', 1.5, 'MarkerSize', 6);
title('Mean of $\mathrm{max}[g^{(2)}_{[50,70]}(\delta\theta)]$', ...
'Interpreter', 'latex', 'FontSize', title_fontsize);
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
ylabel('$\kappa_1$', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
set(gca, 'FontSize', axis_fontsize);
grid on;
% 2. Variance
subplot(3,2,2);
plot(scan_vals, var_max_g2_values, 's-', 'LineWidth', 1.5, 'MarkerSize', 6);
title('Variance of $\mathrm{max}[g^{(2)}_{[50,70]}(\delta\theta)]$', ...
'Interpreter', 'latex', 'FontSize', title_fontsize);
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
ylabel('$\kappa_2$', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
set(gca, 'FontSize', axis_fontsize);
grid on;
% 3. Skewness
subplot(3,2,3);
plot(scan_vals, skew_max_g2_angle_values, 'd-', 'LineWidth', 1.5, 'MarkerSize', 6);
title('Skewness of $\mathrm{max}[g^{(2)}_{[50,70]}(\delta\theta)]$', ...
'Interpreter', 'latex', 'FontSize', title_fontsize);
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
ylabel('$\kappa_3$', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
set(gca, 'FontSize', axis_fontsize);
grid on;
% 4. Binder Cumulant
subplot(3,2,4);
plot(scan_vals, fourth_order_cumulant_max_g2_angle_values, '^-', 'LineWidth', 1.5, 'MarkerSize', 6);
title('Binder Cumulant of $\mathrm{max}[g^{(2)}_{[50,70]}(\delta\theta)]$', ...
'Interpreter', 'latex', 'FontSize', title_fontsize);
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
ylabel('$\kappa_4$', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
set(gca, 'FontSize', axis_fontsize);
grid on;
% 5. 5th-order cumulant
subplot(3,2,5);
plot(scan_vals, fifth_order_cumulant_max_g2_angle_values, 'v-', 'LineWidth', 1.5, 'MarkerSize', 6);
title('Fifth-order cumulant of $\mathrm{max}[g^{(2)}_{[50,70]}(\delta\theta)]$', ...
'Interpreter', 'latex', 'FontSize', title_fontsize);
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
ylabel('$\kappa_5$', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
set(gca, 'FontSize', axis_fontsize);
grid on;
% 6. 6th-order cumulant
subplot(3,2,6);
plot(scan_vals, sixth_order_cumulant_max_g2_angle_values, '>-', 'LineWidth', 1.5, 'MarkerSize', 6);
title('Sixth-order cumulant of $\mathrm{max}[g^{(2)}_{[50,70]}(\delta\theta)]$', ...
'Interpreter', 'latex', 'FontSize', title_fontsize);
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
ylabel('$\kappa_6$', 'Interpreter', 'latex', ...
'FontSize', label_fontsize);
set(gca, 'FontSize', axis_fontsize);
grid on;
% Super title
sgtitle(sprintf('Cumulants of Peak Offset Angular Correlation - %s', titleString), ...
'FontWeight', 'bold', 'FontSize', 16, 'Interpreter', 'latex');
%% Mean ± Std vs. scan parameter
% Plot mean ± SEM
figure(1);
set(gcf, 'Color', 'w', 'Position',[100 100 950 750])
set(gca, 'FontSize', 14); % For tick labels only
errorbar(unique_scan_parameter_values, ... % x-axis
mean_max_g2_values, ... % y-axis (mean)
std_error_g2_values, ... % ± SEM
'--o', 'LineWidth', 1.8, 'MarkerSize', 6 );
set(gca, 'FontSize', 14, 'YLim', [0, 1]);
hXLabel = xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex');
hYLabel = ylabel('$\mathrm{max}[g^{(2)}_{[50,70]}(\delta\theta)]$', 'Interpreter', 'latex');
hTitle = title(titleString, 'Interpreter', 'tex');
% set([hXLabel, hYLabel], 'FontName', font);
set([hXLabel, hYLabel], 'FontSize', 14);
set(hTitle, 'FontName', font, 'FontSize', 16, 'FontWeight', 'bold');
grid on;
% Define folder for saving images
saveFolder = [savefileName '_SavedFigures'];
if ~exist(saveFolder, 'dir')
mkdir(saveFolder);
end
save([saveFolder savefileName '.mat'], 'unique_scan_parameter_values', 'mean_max_g2_values', 'std_error_g2_values');
%% Helper Functions
function [IMGFFT, IMGPR] = computeFourierTransform(I, skipPreprocessing, skipMasking, skipIntensityThresholding, skipBinarization)
% computeFourierSpectrum - Computes the 2D Fourier power spectrum
% of binarized and enhanced lattice image features, with optional central mask.
%
% Inputs:
% I - Grayscale or RGB image matrix
%
% Output:
% F_mag - 2D Fourier power spectrum (shifted)
if ~skipPreprocessing
% Preprocessing: Denoise
filtered = imgaussfilt(I, 10);
IMGPR = I - filtered; % adjust sigma as needed
else
IMGPR = I;
end
if ~skipMasking
[rows, cols] = size(IMGPR);
[X, Y] = meshgrid(1:cols, 1:rows);
% Elliptical mask parameters
cx = cols / 2;
cy = rows / 2;
% Shifted coordinates
x = X - cx;
y = Y - cy;
% Ellipse semi-axes
rx = 0.4 * cols;
ry = 0.2 * rows;
% Rotation angle in degrees -> radians
theta_deg = 30; % Adjust as needed
theta = deg2rad(theta_deg);
% Rotated ellipse equation
cos_t = cos(theta);
sin_t = sin(theta);
x_rot = (x * cos_t + y * sin_t);
y_rot = (-x * sin_t + y * cos_t);
ellipseMask = (x_rot.^2) / rx^2 + (y_rot.^2) / ry^2 <= 1;
% Apply cutout mask
IMGPR = IMGPR .* ellipseMask;
end
if ~skipIntensityThresholding
% Apply global intensity threshold mask
intensity_thresh = 0.20;
intensity_mask = IMGPR > intensity_thresh;
IMGPR = IMGPR .* intensity_mask;
end
if ~skipBinarization
% Adaptive binarization and cleanup
IMGPR = imbinarize(IMGPR, 'adaptive', 'Sensitivity', 0.0);
IMGPR = imdilate(IMGPR, strel('disk', 2));
IMGPR = imerode(IMGPR, strel('disk', 1));
IMGPR = imfill(IMGPR, 'holes');
F = fft2(double(IMGPR)); % Compute 2D Fourier Transform
IMGFFT = abs(fftshift(F))'; % Shift zero frequency to center
else
F = fft2(double(IMGPR)); % Compute 2D Fourier Transform
IMGFFT = abs(fftshift(F))'; % Shift zero frequency to center
end
end
function [theta_vals, S_theta] = computeAngularSpectralDistribution(IMGFFT, r_min, r_max, num_bins, threshold, sigma, windowSize)
% Apply threshold to isolate strong peaks
IMGFFT(IMGFFT < threshold) = 0;
% Prepare polar coordinates
[ny, nx] = size(IMGFFT);
[X, Y] = meshgrid(1:nx, 1:ny);
cx = ceil(nx/2);
cy = ceil(ny/2);
R = sqrt((X - cx).^2 + (Y - cy).^2);
Theta = atan2(Y - cy, X - cx); % range [-pi, pi]
% Choose radial band
radial_mask = (R >= r_min) & (R <= r_max);
% Initialize angular structure factor
S_theta = zeros(1, num_bins);
theta_vals = linspace(0, pi, num_bins);
% Loop through angle bins
for i = 1:num_bins
angle_start = (i-1) * pi / num_bins;
angle_end = i * pi / num_bins;
angle_mask = (Theta >= angle_start & Theta < angle_end);
bin_mask = radial_mask & angle_mask;
fft_angle = IMGFFT .* bin_mask;
S_theta(i) = sum(sum(abs(fft_angle).^2));
end
% Smooth using either Gaussian or moving average
if exist('sigma', 'var') && ~isempty(sigma)
% Gaussian convolution
half_width = ceil(3 * sigma);
x = -half_width:half_width;
gauss_kernel = exp(-x.^2 / (2 * sigma^2));
gauss_kernel = gauss_kernel / sum(gauss_kernel);
% Circular convolution
S_theta = conv([S_theta(end-half_width+1:end), S_theta, S_theta(1:half_width)], ...
gauss_kernel, 'same');
S_theta = S_theta(half_width+1:end-half_width);
elseif exist('windowSize', 'var') && ~isempty(windowSize)
% Moving average via convolution (circular)
pad = floor(windowSize / 2);
kernel = ones(1, windowSize) / windowSize;
S_theta = conv([S_theta(end-pad+1:end), S_theta, S_theta(1:pad)], kernel, 'same');
S_theta = S_theta(pad+1:end-pad);
end
end
function ret = getBkgOffsetFromCorners(img, x_fraction, y_fraction)
% image must be a 2D numerical array
[dim1, dim2] = size(img);
s1 = img(1:round(dim1 * y_fraction), 1:round(dim2 * x_fraction));
s2 = img(1:round(dim1 * y_fraction), round(dim2 - dim2 * x_fraction):dim2);
s3 = img(round(dim1 - dim1 * y_fraction):dim1, 1:round(dim2 * x_fraction));
s4 = img(round(dim1 - dim1 * y_fraction):dim1, round(dim2 - dim2 * x_fraction):dim2);
ret = mean([mean(s1(:)), mean(s2(:)), mean(s3(:)), mean(s4(:))]);
end
function ret = subtractBackgroundOffset(img, fraction)
% Remove the background from the image.
% :param dataArray: The image
% :type dataArray: xarray DataArray
% :param x_fraction: The fraction of the pixels used in x axis
% :type x_fraction: float
% :param y_fraction: The fraction of the pixels used in y axis
% :type y_fraction: float
% :return: The image after removing background
% :rtype: xarray DataArray
x_fraction = fraction(1);
y_fraction = fraction(2);
offset = getBkgOffsetFromCorners(img, x_fraction, y_fraction);
ret = img - offset;
end
function ret = cropODImage(img, center, span)
% Crop the image according to the region of interest (ROI).
% :param dataSet: The images
% :type dataSet: xarray DataArray or DataSet
% :param center: The center of region of interest (ROI)
% :type center: tuple
% :param span: The span of region of interest (ROI)
% :type span: tuple
% :return: The cropped images
% :rtype: xarray DataArray or DataSet
x_start = floor(center(1) - span(1) / 2);
x_end = floor(center(1) + span(1) / 2);
y_start = floor(center(2) - span(2) / 2);
y_end = floor(center(2) + span(2) / 2);
ret = img(y_start:y_end, x_start:x_end);
end
function imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%CALCULATEODIMAGE Calculates the optical density (OD) image for absorption imaging.
%
% imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%
% Inputs:
% imageAtom - Image with atoms
% imageBackground - Image without atoms
% imageDark - Image without light
% mode - 'LowIntensity' (default) or 'HighIntensity'
% exposureTime - Required only for 'HighIntensity' [in seconds]
%
% Output:
% imageOD - Computed OD image
%
arguments
imageAtom (:,:) {mustBeNumeric}
imageBackground (:,:) {mustBeNumeric}
imageDark (:,:) {mustBeNumeric}
mode char {mustBeMember(mode, {'LowIntensity', 'HighIntensity'})} = 'LowIntensity'
exposureTime double = NaN
end
% Compute numerator and denominator
numerator = imageBackground - imageDark;
denominator = imageAtom - imageDark;
% Avoid division by zero
numerator(numerator == 0) = 1;
denominator(denominator == 0) = 1;
% Calculate OD based on mode
switch mode
case 'LowIntensity'
imageOD = -log(abs(denominator ./ numerator));
case 'HighIntensity'
if isnan(exposureTime)
error('Exposure time must be provided for HighIntensity mode.');
end
imageOD = abs(denominator ./ numerator);
imageOD = -log(imageOD) + (numerator - denominator) ./ (7000 * (exposureTime / 5e-6));
end
end
function [optrefimages] = removefringesInImage(absimages, refimages, bgmask)
% removefringesInImage - Fringe removal and noise reduction from absorption images.
% Creates an optimal reference image for each absorption image in a set as
% a linear combination of reference images, with coefficients chosen to
% minimize the least-squares residuals between each absorption image and
% the optimal reference image. The coefficients are obtained by solving a
% linear set of equations using matrix inverse by LU decomposition.
%
% Application of the algorithm is described in C. F. Ockeloen et al, Improved
% detection of small atom numbers through image processing, arXiv:1007.2136 (2010).
%
% Syntax:
% [optrefimages] = removefringesInImage(absimages,refimages,bgmask);
%
% Required inputs:
% absimages - Absorption image data,
% typically 16 bit grayscale images
% refimages - Raw reference image data
% absimages and refimages are both cell arrays containing
% 2D array data. The number of refimages can differ from the
% number of absimages.
%
% Optional inputs:
% bgmask - Array specifying background region used,
% 1=background, 0=data. Defaults to all ones.
% Outputs:
% optrefimages - Cell array of optimal reference images,
% equal in size to absimages.
%
% Dependencies: none
%
% Authors: Shannon Whitlock, Caspar Ockeloen
% Reference: C. F. Ockeloen, A. F. Tauschinsky, R. J. C. Spreeuw, and
% S. Whitlock, Improved detection of small atom numbers through
% image processing, arXiv:1007.2136
% Email:
% May 2009; Last revision: 11 August 2010
% Process inputs
% Set variables, and flatten absorption and reference images
nimgs = size(absimages,3);
nimgsR = size(refimages,3);
xdim = size(absimages(:,:,1),2);
ydim = size(absimages(:,:,1),1);
R = single(reshape(refimages,xdim*ydim,nimgsR));
A = single(reshape(absimages,xdim*ydim,nimgs));
optrefimages=zeros(size(absimages)); % preallocate
if not(exist('bgmask','var')); bgmask=ones(ydim,xdim); end
k = find(bgmask(:)==1); % Index k specifying background region
% Ensure there are no duplicate reference images
% R=unique(R','rows')'; % comment this line if you run out of memory
% Decompose B = R*R' using singular value or LU decomposition
[L,U,p] = lu(R(k,:)'*R(k,:),'vector'); % LU decomposition
for j=1:nimgs
b=R(k,:)'*A(k,j);
% Obtain coefficients c which minimise least-square residuals
lower.LT = true; upper.UT = true;
c = linsolve(U,linsolve(L,b(p,:),lower),upper);
% Compute optimised reference image
optrefimages(:,:,j)=reshape(R*c,[ydim xdim]);
end
end

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@ -0,0 +1,158 @@
%% Parameters
% === Define folders and settings ===
baseFolder = '//DyLabNAS/Data/TwoDGas/2025/04/';
dates = ["01", "02"]; % Example: three folders
runs = {
["0059", "0060", "0061"],
["0007", "0008", "0009", "0010", "0011"]
};
options.scan_parameter = 'rot_mag_fin_pol_angle';
options.scan_groups = 0:10:50;
options.cam = 5;
% Image cropping and alignment
options.angle = 0;
options.center = [1285, 2100];
options.span = [200, 200];
options.fraction = [0.1, 0.1];
% Imaging and calibration parameters
options.pixel_size = 5.86e-6; % in meters
options.magnification = 23.94;
options.removeFringes = false;
options.ImagingMode = 'HighIntensity';
options.PulseDuration = 5e-6;
% Fourier analysis: Radial
options.theta_min = deg2rad(0);
options.theta_max = deg2rad(180);
options.N_radial_bins = 500;
options.Radial_Sigma = 2;
options.Radial_WindowSize = 5; % Must be odd
% Fourier analysis: Angular
options.r_min = 10;
options.r_max = 20;
options.k_min = 1.2771; % in μm¹
options.k_max = 2.5541; % in μm¹
options.N_angular_bins = 180;
options.Angular_Threshold = 75;
options.Angular_Sigma = 2;
options.Angular_WindowSize = 5;
% Optional visualization / zooming
options.zoom_size = 50;
% Optional flags or settings struct
options.skipUnshuffling = false;
options.skipPreprocessing = true;
options.skipMasking = true;
options.skipIntensityThresholding = true;
options.skipBinarization = true;
% === Loop through folders and collect results ===
results_all = [];
assert(length(dates) == length(runs), ...
'Each entry in `dates` must correspond to a cell in `runs`.');
for i = 1:length(dates)
currentDate = dates(i);
currentRuns = runs{i};
for j = 1:length(currentRuns)
runID = currentRuns(j);
folderPath = fullfile(baseFolder, currentDate, runID);
if ~endsWith(folderPath, filesep)
options.folderPath = [char(folderPath) filesep];
else
options.folderPath = char(folderPath);
end
try
% Unpack options struct into name-value pairs
args = [fieldnames(options), struct2cell(options)]';
args = args(:)';
results = analyzeFolder(args{:});
results_all = [results_all; results];
catch ME
warning("Error processing %s/%s: %s", currentDate, runID, ME.message);
end
end
end
%% Plotting heatmap of mean_max_g2_values
N_x = length(options.scan_groups);
N_y = length(results_all);
BFields = [2.35, 2.15, 2.0, 1.85, 1.7, 1.55, 1.4, 1.35];
% Preallocate
g2_matrix = zeros(N_y, N_x);
for i = 1:N_y
for j = 1:N_x
g2_matrix(i, j) = results_all(i).mean_max_g2_values(j);
end
end
% Plot heatmap
font = 'Bahnschrift';
figure(1)
clf
set(gcf,'Position',[50 50 950 750])
imagesc(options.scan_groups, BFields, g2_matrix);
colormap(sky);
clim([0, 1])
set(gca, 'FontSize', 14, 'YDir', 'normal');
hXLabel = xlabel('\alpha (degrees)', 'Interpreter', 'tex');
hYLabel = ylabel('BField (G)', 'Interpreter', 'tex');
hTitle = title('$\mathrm{max}[g^{(2)}_{[50,70]}(\delta\theta)]$', 'Interpreter', 'latex');
set([hXLabel, hYLabel], 'FontSize', 14)
set(hTitle, 'FontSize', 16, 'FontWeight', 'bold'); % Set font and size for title
colorbar;
%% Heat map of radial spectral contrast
N_x = length(options.scan_groups);
N_y = length(results_all);
BFields = [2.35, 2.15, 2.0, 1.85, 1.7, 1.55, 1.4, 1.35];
% Preallocate
radial_spectral_contrast_matrix = zeros(N_y, N_x);
for i = 1:N_y
for j = 1:N_x
radial_spectral_contrast_matrix(i, j) = results_all(i).radial_spectral_contrast(j);
end
end
% Plot heatmap
font = 'Bahnschrift';
figure(3)
clf
set(gcf,'Position',[50 50 950 750])
imagesc(options.scan_groups, BFields, radial_spectral_contrast_matrix);
colormap(sky);
clim([0 0.008])
set(gca, 'FontSize', 14, 'YDir', 'normal');
hXLabel = xlabel('\alpha (degrees)', 'Interpreter', 'tex');
hYLabel = ylabel('BField (G)', 'Interpreter', 'tex');
hTitle = title('Radial Spectral Contrast');
set([hXLabel, hYLabel], 'FontSize', 14)
set(hTitle, 'FontName', font, 'FontSize', 16, 'FontWeight', 'bold'); % Set font and size for title
colorbar;

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%% Parameters
groupList = ["/images/MOT_3D_Camera/in_situ_absorption", "/images/ODT_1_Axis_Camera/in_situ_absorption", ...
"/images/ODT_2_Axis_Camera/in_situ_absorption", "/images/Horizontal_Axis_Camera/in_situ_absorption", ...
"/images/Vertical_Axis_Camera/in_situ_absorption"];
folderPath = "//DyLabNAS/Data/TwoDGas/2025/07/16/";
run = '0002';
folderPath = strcat(folderPath, run);
cam = 5;
angle = 0;
center = [1430, 2025];
span = [200, 200];
fraction = [0.1, 0.1];
pixel_size = 5.86e-6; % in meters
magnification = 23.94;
removeFringes = false;
ImagingMode = 'HighIntensity';
PulseDuration = 5e-6;
% Plotting and saving
scan_parameter = 'evap_rot_mag_field';
scan_groups = 0:10:50;
savefileName = 'Droplets';
font = 'Bahnschrift';
% Flags
skipUnshuffling = true;
%% ===== Load and compute OD image, rotate and extract ROI for analysis =====
% Get a list of all files in the folder with the desired file name pattern.
filePattern = fullfile(folderPath, '*.h5');
files = dir(filePattern);
refimages = zeros(span(1) + 1, span(2) + 1, length(files));
absimages = zeros(span(1) + 1, span(2) + 1, length(files));
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
fprintf(1, 'Now reading %s\n', fullFileName);
atm_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/atoms")), angle));
bkg_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/background")), angle));
dark_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/dark")), angle));
refimages(:,:,k) = subtractBackgroundOffset(cropODImage(bkg_img, center, span), fraction)';
absimages(:,:,k) = subtractBackgroundOffset(cropODImage(calculateODImage(atm_img, bkg_img, dark_img, ImagingMode, PulseDuration), center, span), fraction)';
end
% ===== Fringe removal =====
if removeFringes
optrefimages = removefringesInImage(absimages, refimages);
absimages_fringe_removed = absimages(:, :, :) - optrefimages(:, :, :);
nimgs = size(absimages_fringe_removed,3);
od_imgs = cell(1, nimgs);
for i = 1:nimgs
od_imgs{i} = absimages_fringe_removed(:, :, i);
end
else
nimgs = size(absimages(:, :, :),3);
od_imgs = cell(1, nimgs);
for i = 1:nimgs
od_imgs{i} = absimages(:, :, i);
end
end
% ===== Get rotation angles =====
scan_parameter_values = zeros(1, length(files));
% Get information about the '/globals' group
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
info = h5info(fullFileName, '/globals');
for i = 1:length(info.Attributes)
if strcmp(info.Attributes(i).Name, scan_parameter)
if strcmp(scan_parameter, 'rot_mag_fin_pol_angle')
scan_parameter_values(k) = 180 - info.Attributes(i).Value;
else
scan_parameter_values(k) = info.Attributes(i).Value;
end
end
end
end
% ===== Unshuffle if necessary to do so =====
if ~skipUnshuffling
n_values = length(scan_groups);
n_total = length(scan_parameter_values);
% Infer number of repetitions
n_reps = n_total / n_values;
% Preallocate ordered arrays
ordered_scan_values = zeros(1, n_total);
ordered_od_imgs = cell(1, n_total);
counter = 1;
for rep = 1:n_reps
for val = scan_groups
% Find the next unused match for this val
idx = find(scan_parameter_values == val, 1, 'first');
% Assign and remove from list to avoid duplicates
ordered_scan_values(counter) = scan_parameter_values(idx);
ordered_od_imgs{counter} = od_imgs{idx};
% Mark as used by removing
scan_parameter_values(idx) = NaN; % NaN is safe since original values are 0:5:45
od_imgs{idx} = []; % empty cell so it won't be matched again
counter = counter + 1;
end
end
% Now assign back
scan_parameter_values = ordered_scan_values;
od_imgs = ordered_od_imgs;
end
%% Display Images
figure(1)
clf
set(gcf,'Position',[50 50 950 750])
% Get image size in pixels
[Ny, Nx] = size(od_imgs{1});
% Define pixel size and magnification (if not already defined earlier)
dx = pixel_size / magnification; % e.g. in meters
dy = dx; % assuming square pixels
% Define x and y axes in μm (centered at image center)
x = ((1:Nx) - ceil(Nx/2)) * dx * 1E6; % micrometers
y = ((1:Ny) - ceil(Ny/2)) * dy * 1E6;
% Display the cropped image
for k = 1 : length(od_imgs)
imagesc(x, y, od_imgs{k});
hold on;
% Convert pixel grid to µm (already done: x and y axes)
% Draw diagonal (top-left to bottom-right)
drawODOverlays(x(1), y(1), x(end), y(end));
% Draw diagonal (top-right to bottom-left)
drawODOverlays(x(end), y(1), x(1), y(end));
hold off;
axis equal tight;
colormap(Colormaps.inferno());
set(gca, 'FontSize', 14, 'YDir', 'normal');
if strcmp(scan_parameter, 'rot_mag_fin_pol_angle')
text(0.975, 0.975, [num2str(scan_parameter_values(k), '%.1f^\\circ')], ...
'Color', 'white', 'FontWeight', 'bold', 'FontSize', 24, ...
'Interpreter', 'tex', 'Units', 'normalized', ...
'HorizontalAlignment', 'right', 'VerticalAlignment', 'top');
else
text(0.975, 0.975, [num2str(scan_parameter_values(k), '%.2f'), ' G'], ...
'Color', 'white', 'FontWeight', 'bold', 'FontSize', 24, ...
'Interpreter', 'tex', 'Units', 'normalized', ...
'HorizontalAlignment', 'right', 'VerticalAlignment', 'top');
end
colorbarHandle = colorbar;
ylabel(colorbarHandle, 'Optical Density', 'Rotation', -90, 'FontSize', 14, 'FontName', font);
xlabel('x (\mum)', 'Interpreter', 'tex', 'FontSize', 14, 'FontName', font);
ylabel('y (\mum)', 'Interpreter', 'tex', 'FontSize', 14, 'FontName', font);
title('OD Image', 'FontSize', 16, 'FontWeight', 'bold', 'Interpreter', 'tex', 'FontName', font);
drawnow;
pause(0.5);
end
%% Helper Functions
function ret = getBkgOffsetFromCorners(img, x_fraction, y_fraction)
% image must be a 2D numerical array
[dim1, dim2] = size(img);
s1 = img(1:round(dim1 * y_fraction), 1:round(dim2 * x_fraction));
s2 = img(1:round(dim1 * y_fraction), round(dim2 - dim2 * x_fraction):dim2);
s3 = img(round(dim1 - dim1 * y_fraction):dim1, 1:round(dim2 * x_fraction));
s4 = img(round(dim1 - dim1 * y_fraction):dim1, round(dim2 - dim2 * x_fraction):dim2);
ret = mean([mean(s1(:)), mean(s2(:)), mean(s3(:)), mean(s4(:))]);
end
function ret = subtractBackgroundOffset(img, fraction)
% Remove the background from the image.
% :param dataArray: The image
% :type dataArray: xarray DataArray
% :param x_fraction: The fraction of the pixels used in x axis
% :type x_fraction: float
% :param y_fraction: The fraction of the pixels used in y axis
% :type y_fraction: float
% :return: The image after removing background
% :rtype: xarray DataArray
x_fraction = fraction(1);
y_fraction = fraction(2);
offset = getBkgOffsetFromCorners(img, x_fraction, y_fraction);
ret = img - offset;
end
function ret = cropODImage(img, center, span)
% Crop the image according to the region of interest (ROI).
% :param dataSet: The images
% :type dataSet: xarray DataArray or DataSet
% :param center: The center of region of interest (ROI)
% :type center: tuple
% :param span: The span of region of interest (ROI)
% :type span: tuple
% :return: The cropped images
% :rtype: xarray DataArray or DataSet
x_start = floor(center(1) - span(1) / 2);
x_end = floor(center(1) + span(1) / 2);
y_start = floor(center(2) - span(2) / 2);
y_end = floor(center(2) + span(2) / 2);
ret = img(y_start:y_end, x_start:x_end);
end
function imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%CALCULATEODIMAGE Calculates the optical density (OD) image for absorption imaging.
%
% imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%
% Inputs:
% imageAtom - Image with atoms
% imageBackground - Image without atoms
% imageDark - Image without light
% mode - 'LowIntensity' (default) or 'HighIntensity'
% exposureTime - Required only for 'HighIntensity' [in seconds]
%
% Output:
% imageOD - Computed OD image
%
arguments
imageAtom (:,:) {mustBeNumeric}
imageBackground (:,:) {mustBeNumeric}
imageDark (:,:) {mustBeNumeric}
mode char {mustBeMember(mode, {'LowIntensity', 'HighIntensity'})} = 'LowIntensity'
exposureTime double = NaN
end
% Compute numerator and denominator
numerator = imageBackground - imageDark;
denominator = imageAtom - imageDark;
% Avoid division by zero
numerator(numerator == 0) = 1;
denominator(denominator == 0) = 1;
% Calculate OD based on mode
switch mode
case 'LowIntensity'
imageOD = -log(abs(denominator ./ numerator));
case 'HighIntensity'
if isnan(exposureTime)
error('Exposure time must be provided for HighIntensity mode.');
end
imageOD = abs(denominator ./ numerator);
imageOD = -log(imageOD) + (numerator - denominator) ./ (7000 * (exposureTime / 5e-6));
end
end
function drawODOverlays(x1, y1, x2, y2)
% Parameters
tick_spacing = 10; % µm between ticks
tick_length = 2; % µm tick mark length
line_color = [0.5 0.5 0.5];
tick_color = [0.5 0.5 0.5];
font_size = 10;
% Vector from start to end
dx = x2 - x1;
dy = y2 - y1;
L = sqrt(dx^2 + dy^2);
% Unit direction vector along diagonal
ux = dx / L;
uy = dy / L;
% Perpendicular unit vector for ticks
perp_ux = -uy;
perp_uy = ux;
% Midpoint (center)
xc = (x1 + x2) / 2;
yc = (y1 + y2) / 2;
% Number of positive and negative ticks
n_ticks = floor(L / (2 * tick_spacing));
% Draw main diagonal line
plot([x1 x2], [y1 y2], '--', 'Color', line_color, 'LineWidth', 1.2);
for i = -n_ticks:n_ticks
d = i * tick_spacing;
xt = xc + d * ux;
yt = yc + d * uy;
% Tick line endpoints
xt1 = xt - 0.5 * tick_length * perp_ux;
yt1 = yt - 0.5 * tick_length * perp_uy;
xt2 = xt + 0.5 * tick_length * perp_ux;
yt2 = yt + 0.5 * tick_length * perp_uy;
% Draw tick
plot([xt1 xt2], [yt1 yt2], '--', 'Color', tick_color, 'LineWidth', 1);
% Label: centered at tick, offset slightly along diagonal
if d ~= 0
text(xt, yt, sprintf('%+d', d), ...
'Color', tick_color, ...
'FontSize', font_size, ...
'HorizontalAlignment', 'center', ...
'VerticalAlignment', 'bottom', ...
'Rotation', atan2d(dy, dx));
end
end
end
function [optrefimages] = removefringesInImage(absimages, refimages, bgmask)
% removefringesInImage - Fringe removal and noise reduction from absorption images.
% Creates an optimal reference image for each absorption image in a set as
% a linear combination of reference images, with coefficients chosen to
% minimize the least-squares residuals between each absorption image and
% the optimal reference image. The coefficients are obtained by solving a
% linear set of equations using matrix inverse by LU decomposition.
%
% Application of the algorithm is described in C. F. Ockeloen et al, Improved
% detection of small atom numbers through image processing, arXiv:1007.2136 (2010).
%
% Syntax:
% [optrefimages] = removefringesInImage(absimages,refimages,bgmask);
%
% Required inputs:
% absimages - Absorption image data,
% typically 16 bit grayscale images
% refimages - Raw reference image data
% absimages and refimages are both cell arrays containing
% 2D array data. The number of refimages can differ from the
% number of absimages.
%
% Optional inputs:
% bgmask - Array specifying background region used,
% 1=background, 0=data. Defaults to all ones.
% Outputs:
% optrefimages - Cell array of optimal reference images,
% equal in size to absimages.
%
% Dependencies: none
%
% Authors: Shannon Whitlock, Caspar Ockeloen
% Reference: C. F. Ockeloen, A. F. Tauschinsky, R. J. C. Spreeuw, and
% S. Whitlock, Improved detection of small atom numbers through
% image processing, arXiv:1007.2136
% Email:
% May 2009; Last revision: 11 August 2010
% Process inputs
% Set variables, and flatten absorption and reference images
nimgs = size(absimages,3);
nimgsR = size(refimages,3);
xdim = size(absimages(:,:,1),2);
ydim = size(absimages(:,:,1),1);
R = single(reshape(refimages,xdim*ydim,nimgsR));
A = single(reshape(absimages,xdim*ydim,nimgs));
optrefimages=zeros(size(absimages)); % preallocate
if not(exist('bgmask','var')); bgmask=ones(ydim,xdim); end
k = find(bgmask(:)==1); % Index k specifying background region
% Ensure there are no duplicate reference images
% R=unique(R','rows')'; % comment this line if you run out of memory
% Decompose B = R*R' using singular value or LU decomposition
[L,U,p] = lu(R(k,:)'*R(k,:),'vector'); % LU decomposition
for j=1:nimgs
b=R(k,:)'*A(k,j);
% Obtain coefficients c which minimise least-square residuals
lower.LT = true; upper.UT = true;
c = linsolve(U,linsolve(L,b(p,:),lower),upper);
% Compute optimised reference image
optrefimages(:,:,j)=reshape(R*c,[ydim xdim]);
end
end

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% === Parameters ===
baseFolder = '//DyLabNAS/Data/TwoDGas/2025/04/';
dates = ["01", "02"];
runs = {
["0059", "0060", "0061"],
["0007", "0008", "0009", "0010", "0011"]
};
scan_groups = 0:10:50;
scan_parameter = 'rot_mag_fin_pol_angle';
cam = 5;
% Image cropping and alignment
angle = 0;
center = [1285, 2100];
span = [200, 200];
fraction = [0.1, 0.1];
% Imaging and calibration parameters
pixel_size = 5.86e-6; % in meters
magnification = 23.94;
removeFringes = false;
ImagingMode = 'LowIntensity';
PulseDuration = 5e-6;
% Optional visualization / zooming
options.zoom_size = 50;
% Optional flags or settings struct
skipUnshuffling = false;
skipPreprocessing = true;
skipMasking = true;
skipIntensityThresholding = true;
skipBinarization = true;
groupList = ["/images/MOT_3D_Camera/in_situ_absorption", "/images/ODT_1_Axis_Camera/in_situ_absorption", ...
"/images/ODT_2_Axis_Camera/in_situ_absorption", "/images/Horizontal_Axis_Camera/in_situ_absorption", ...
"/images/Vertical_Axis_Camera/in_situ_absorption"];
%%
allData = {}; % now a growing list of structs per B field
dataCounter = 1;
for i = 1:length(dates)
dateStr = dates(i);
runList = runs{i};
for j = 1:length(runList)
folderPath = fullfile(baseFolder, dateStr, runList{j});
filePattern = fullfile(folderPath, '*.h5');
files = dir(filePattern);
refimages = zeros(span(1) + 1, span(2) + 1, length(files));
absimages = zeros(span(1) + 1, span(2) + 1, length(files));
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
fprintf(1, 'Now reading %s\n', fullFileName);
atm_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/atoms")), angle));
bkg_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/background")), angle));
dark_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/dark")), angle));
refimages(:,:,k) = subtractBackgroundOffset(cropODImage(bkg_img, center, span), fraction)';
absimages(:,:,k) = subtractBackgroundOffset(cropODImage(calculateODImage(atm_img, bkg_img, dark_img, ImagingMode, PulseDuration), center, span), fraction)';
end
% ===== Fringe removal =====
if removeFringes
optrefimages = removefringesInImage(absimages, refimages);
absimages_fringe_removed = absimages(:, :, :) - optrefimages(:, :, :);
nimgs = size(absimages_fringe_removed,3);
od_imgs = cell(1, nimgs);
for k = 1:nimgs
od_imgs{k} = absimages_fringe_removed(:, :, k);
end
else
nimgs = size(absimages(:, :, :),3);
od_imgs = cell(1, nimgs);
for k = 1:nimgs
od_imgs{k} = absimages(:, :, k);
end
end
%% ===== Get rotation angles =====
scan_parameter_values = zeros(1, length(files));
% Get information about the '/globals' group
for k = 1 : length(files)
baseFileName = files(k).name;
fullFileName = fullfile(files(k).folder, baseFileName);
info = h5info(fullFileName, '/globals');
for i = 1:length(info.Attributes)
if strcmp(info.Attributes(i).Name, scan_parameter)
if strcmp(scan_parameter, 'rot_mag_fin_pol_angle')
scan_parameter_values(k) = 180 - info.Attributes(i).Value;
else
scan_parameter_values(k) = info.Attributes(i).Value;
end
end
if strcmp(info.Attributes(i).Name, "rot_mag_field")
B = info.Attributes(i).Value;
end
end
end
% ===== Unshuffle if necessary to do so =====
if ~skipUnshuffling
n_values = length(scan_groups);
n_total = length(scan_parameter_values);
% Infer number of repetitions
n_reps = n_total / n_values;
% Preallocate ordered arrays
ordered_scan_values = zeros(1, n_total);
ordered_od_imgs = cell(1, n_total);
counter = 1;
for rep = 1:n_reps
for val = scan_groups
% Find the next unused match for this val
idx = find(scan_parameter_values == val, 1, 'first');
% Assign and remove from list to avoid duplicates
ordered_scan_values(counter) = scan_parameter_values(idx);
ordered_od_imgs{counter} = od_imgs{idx};
% Mark as used by removing
scan_parameter_values(idx) = NaN; % NaN is safe since original values are 0:5:45
od_imgs{idx} = []; % empty cell so it won't be matched again
counter = counter + 1;
end
end
% Now assign back
scan_parameter_values = ordered_scan_values;
od_imgs = ordered_od_imgs;
end
% === Reshape ===
od_imgs_reshaped = reshape(od_imgs, [length(scan_groups), n_reps]);
% === Store ===
allData{dataCounter} = struct(...
'B', B, ...
'theta_vals', scan_groups, ...
'od_imgs', od_imgs_reshaped ...
);
dataCounter = dataCounter + 1;
end
end
%% === % Plot PD - 1st rep of each θ per B-field ===
[theta_vals, ~, idx] = unique(scan_parameter_values);
nB = numel(allData);
nTheta = numel(theta_vals);
% Select every 2nd B-field index
idxToPlot = 1:2:nB; % indices 1, 3, 5, ...
% Update number of B-fields to plot
nB_new = numel(idxToPlot);
figure(101); clf;
% Make the figure wider to fit the colorbar comfortably
set(gcf, 'Position', [100, 100, 1300, 800]);
% Create tiled layout with some right padding to reserve space for colorbar
t = tiledlayout(nB_new, nTheta, 'TileSpacing', 'compact', 'Padding', 'compact');
font = 'Bahnschrift';
allAxes = gobjects(nB_new, nTheta);
for new_i = 1:nB_new
i = idxToPlot(new_i); % original index in allData
data = allData{i};
for j = 1:nTheta
ax = nexttile((new_i-1)*nTheta + j);
allAxes(new_i,j) = ax;
od = data(j).od_imgs;
imagesc(od, 'Parent', ax);
set(ax, 'YDir', 'normal');
axis(ax, 'image');
ax.XTick = [];
ax.YTick = [];
colormap(ax, Colormaps.inferno());
end
end
% Use colorbar associated with the last image tile
cb = colorbar('Location', 'eastoutside');
cb.Layout.Tile = 'east'; % Attach it to the layout edge
cb.FontName = font;
cb.FontSize = 18;
cb.Label.FontSize = 20;
cb.Label.Rotation = 90;
cb.Label.VerticalAlignment = 'bottom';
cb.Label.HorizontalAlignment = 'center';
cb.Direction = 'normal'; % Ensure ticks go bottom-to-top
% Add x and y tick labels along bottom and left
% Use bottom row for θ ticks
for j = 1:nTheta
ax = allAxes(end, j);
ax.XTick = size(od,2)/2;
ax.XTickLabel = sprintf('%d°', theta_vals(j));
ax.XTickLabelRotation = 0;
ax.FontName = font;
ax.FontSize = 20;
end
% Use first column for B ticks (only the plotted subset)
for new_i = 1:nB_new
i = idxToPlot(new_i);
ax = allAxes(new_i, 1);
ax.YTick = size(od,1)/2;
ax.YTickLabel = sprintf('%.2f G', allData{i}(1).B);
ax.FontName = font;
ax.FontSize = 20;
end
%% Helper Functions
function [IMGFFT, IMGPR] = computeFourierTransform(I, skipPreprocessing, skipMasking, skipIntensityThresholding, skipBinarization)
% computeFourierSpectrum - Computes the 2D Fourier power spectrum
% of binarized and enhanced lattice image features, with optional central mask.
%
% Inputs:
% I - Grayscale or RGB image matrix
%
% Output:
% F_mag - 2D Fourier power spectrum (shifted)
if ~skipPreprocessing
% Preprocessing: Denoise
filtered = imgaussfilt(I, 10);
IMGPR = I - filtered; % adjust sigma as needed
else
IMGPR = I;
end
if ~skipMasking
[rows, cols] = size(IMGPR);
[X, Y] = meshgrid(1:cols, 1:rows);
% Elliptical mask parameters
cx = cols / 2;
cy = rows / 2;
% Shifted coordinates
x = X - cx;
y = Y - cy;
% Ellipse semi-axes
rx = 0.4 * cols;
ry = 0.2 * rows;
% Rotation angle in degrees -> radians
theta_deg = 30; % Adjust as needed
theta = deg2rad(theta_deg);
% Rotated ellipse equation
cos_t = cos(theta);
sin_t = sin(theta);
x_rot = (x * cos_t + y * sin_t);
y_rot = (-x * sin_t + y * cos_t);
ellipseMask = (x_rot.^2) / rx^2 + (y_rot.^2) / ry^2 <= 1;
% Apply cutout mask
IMGPR = IMGPR .* ellipseMask;
end
if ~skipIntensityThresholding
% Apply global intensity threshold mask
intensity_thresh = 0.20;
intensity_mask = IMGPR > intensity_thresh;
IMGPR = IMGPR .* intensity_mask;
end
if ~skipBinarization
% Adaptive binarization and cleanup
IMGPR = imbinarize(IMGPR, 'adaptive', 'Sensitivity', 0.0);
IMGPR = imdilate(IMGPR, strel('disk', 2));
IMGPR = imerode(IMGPR, strel('disk', 1));
IMGPR = imfill(IMGPR, 'holes');
F = fft2(double(IMGPR)); % Compute 2D Fourier Transform
IMGFFT = abs(fftshift(F))'; % Shift zero frequency to center
else
F = fft2(double(IMGPR)); % Compute 2D Fourier Transform
IMGFFT = abs(fftshift(F))'; % Shift zero frequency to center
end
end
function [k_rho_vals, S_radial] = computeRadialSpectralDistribution(IMGFFT, kx, ky, thetamin, thetamax, num_bins)
% IMGFFT : 2D FFT image (fftshifted and cropped)
% kx, ky : 1D physical wavenumber axes [μm¹] matching FFT size
% thetamin : Minimum angle (in radians)
% thetamax : Maximum angle (in radians)
% num_bins : Number of radial bins
[KX, KY] = meshgrid(kx, ky);
K_rho = sqrt(KX.^2 + KY.^2);
Theta = atan2(KY, KX);
if thetamin < thetamax
angle_mask = (Theta >= thetamin) & (Theta <= thetamax);
else
angle_mask = (Theta >= thetamin) | (Theta <= thetamax);
end
power_spectrum = abs(IMGFFT).^2;
r_min = min(K_rho(angle_mask));
r_max = max(K_rho(angle_mask));
r_edges = linspace(r_min, r_max, num_bins + 1);
k_rho_vals = 0.5 * (r_edges(1:end-1) + r_edges(2:end));
S_radial = zeros(1, num_bins);
for i = 1:num_bins
r_low = r_edges(i);
r_high = r_edges(i + 1);
radial_mask = (K_rho >= r_low) & (K_rho < r_high);
full_mask = radial_mask & angle_mask;
S_radial(i) = sum(power_spectrum(full_mask));
end
end
function [theta_vals, S_theta] = computeAngularSpectralDistribution(IMGFFT, r_min, r_max, num_bins, threshold, sigma, windowSize)
% Apply threshold to isolate strong peaks
IMGFFT(IMGFFT < threshold) = 0;
% Prepare polar coordinates
[ny, nx] = size(IMGFFT);
[X, Y] = meshgrid(1:nx, 1:ny);
cx = ceil(nx/2);
cy = ceil(ny/2);
R = sqrt((X - cx).^2 + (Y - cy).^2);
Theta = atan2(Y - cy, X - cx); % range [-pi, pi]
% Choose radial band
radial_mask = (R >= r_min) & (R <= r_max);
% Initialize angular structure factor
S_theta = zeros(1, num_bins);
theta_vals = linspace(0, pi, num_bins);
% Loop through angle bins
for i = 1:num_bins
angle_start = (i-1) * pi / num_bins;
angle_end = i * pi / num_bins;
angle_mask = (Theta >= angle_start & Theta < angle_end);
bin_mask = radial_mask & angle_mask;
fft_angle = IMGFFT .* bin_mask;
S_theta(i) = sum(sum(abs(fft_angle).^2));
end
% Smooth using either Gaussian or moving average
if exist('sigma', 'var') && ~isempty(sigma)
% Gaussian convolution
half_width = ceil(3 * sigma);
x = -half_width:half_width;
gauss_kernel = exp(-x.^2 / (2 * sigma^2));
gauss_kernel = gauss_kernel / sum(gauss_kernel);
% Circular convolution
S_theta = conv([S_theta(end-half_width+1:end), S_theta, S_theta(1:half_width)], ...
gauss_kernel, 'same');
S_theta = S_theta(half_width+1:end-half_width);
elseif exist('windowSize', 'var') && ~isempty(windowSize)
% Moving average via convolution (circular)
pad = floor(windowSize / 2);
kernel = ones(1, windowSize) / windowSize;
S_theta = conv([S_theta(end-pad+1:end), S_theta, S_theta(1:pad)], kernel, 'same');
S_theta = S_theta(pad+1:end-pad);
end
end
function contrast = computeRadialSpectralContrast(IMGFFT, r_min, r_max, threshold)
% Apply threshold to isolate strong peaks
IMGFFT(IMGFFT < threshold) = 0;
% Prepare polar coordinates
[ny, nx] = size(IMGFFT);
[X, Y] = meshgrid(1:nx, 1:ny);
cx = ceil(nx/2);
cy = ceil(ny/2);
R = sqrt((X - cx).^2 + (Y - cy).^2);
% Ring region (annulus) mask
ring_mask = (R >= r_min) & (R <= r_max);
% Squared magnitude in the ring
ring_power = abs(IMGFFT).^2 .* ring_mask;
% Maximum power in the ring
ring_max = max(ring_power(:));
% Power at the DC component
dc_power = abs(IMGFFT(cy, cx))^2;
% Avoid division by zero
if dc_power == 0
contrast = Inf; % or NaN or 0, depending on how you want to handle this
else
contrast = ring_max / dc_power;
end
end
function ret = getBkgOffsetFromCorners(img, x_fraction, y_fraction)
% image must be a 2D numerical array
[dim1, dim2] = size(img);
s1 = img(1:round(dim1 * y_fraction), 1:round(dim2 * x_fraction));
s2 = img(1:round(dim1 * y_fraction), round(dim2 - dim2 * x_fraction):dim2);
s3 = img(round(dim1 - dim1 * y_fraction):dim1, 1:round(dim2 * x_fraction));
s4 = img(round(dim1 - dim1 * y_fraction):dim1, round(dim2 - dim2 * x_fraction):dim2);
ret = mean([mean(s1(:)), mean(s2(:)), mean(s3(:)), mean(s4(:))]);
end
function ret = subtractBackgroundOffset(img, fraction)
% Remove the background from the image.
% :param dataArray: The image
% :type dataArray: xarray DataArray
% :param x_fraction: The fraction of the pixels used in x axis
% :type x_fraction: float
% :param y_fraction: The fraction of the pixels used in y axis
% :type y_fraction: float
% :return: The image after removing background
% :rtype: xarray DataArray
x_fraction = fraction(1);
y_fraction = fraction(2);
offset = getBkgOffsetFromCorners(img, x_fraction, y_fraction);
ret = img - offset;
end
function ret = cropODImage(img, center, span)
% Crop the image according to the region of interest (ROI).
% :param dataSet: The images
% :type dataSet: xarray DataArray or DataSet
% :param center: The center of region of interest (ROI)
% :type center: tuple
% :param span: The span of region of interest (ROI)
% :type span: tuple
% :return: The cropped images
% :rtype: xarray DataArray or DataSet
x_start = floor(center(1) - span(1) / 2);
x_end = floor(center(1) + span(1) / 2);
y_start = floor(center(2) - span(2) / 2);
y_end = floor(center(2) + span(2) / 2);
ret = img(y_start:y_end, x_start:x_end);
end
function imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%CALCULATEODIMAGE Calculates the optical density (OD) image for absorption imaging.
%
% imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
%
% Inputs:
% imageAtom - Image with atoms
% imageBackground - Image without atoms
% imageDark - Image without light
% mode - 'LowIntensity' (default) or 'HighIntensity'
% exposureTime - Required only for 'HighIntensity' [in seconds]
%
% Output:
% imageOD - Computed OD image
%
arguments
imageAtom (:,:) {mustBeNumeric}
imageBackground (:,:) {mustBeNumeric}
imageDark (:,:) {mustBeNumeric}
mode char {mustBeMember(mode, {'LowIntensity', 'HighIntensity'})} = 'LowIntensity'
exposureTime double = NaN
end
% Compute numerator and denominator
numerator = imageBackground - imageDark;
denominator = imageAtom - imageDark;
% Avoid division by zero
numerator(numerator == 0) = 1;
denominator(denominator == 0) = 1;
% Calculate OD based on mode
switch mode
case 'LowIntensity'
imageOD = -log(abs(denominator ./ numerator));
case 'HighIntensity'
if isnan(exposureTime)
error('Exposure time must be provided for HighIntensity mode.');
end
imageOD = abs(denominator ./ numerator);
imageOD = -log(imageOD) + (numerator - denominator) ./ (7000 * (exposureTime / 5e-6));
end
end
function drawODOverlays(x1, y1, x2, y2)
% Parameters
tick_spacing = 10; % µm between ticks
tick_length = 2; % µm tick mark length
line_color = [0.5 0.5 0.5];
tick_color = [0.5 0.5 0.5];
font_size = 10;
% Vector from start to end
dx = x2 - x1;
dy = y2 - y1;
L = sqrt(dx^2 + dy^2);
% Unit direction vector along diagonal
ux = dx / L;
uy = dy / L;
% Perpendicular unit vector for ticks
perp_ux = -uy;
perp_uy = ux;
% Midpoint (center)
xc = (x1 + x2) / 2;
yc = (y1 + y2) / 2;
% Number of positive and negative ticks
n_ticks = floor(L / (2 * tick_spacing));
% Draw main diagonal line
plot([x1 x2], [y1 y2], '--', 'Color', line_color, 'LineWidth', 1.2);
for i = -n_ticks:n_ticks
d = i * tick_spacing;
xt = xc + d * ux;
yt = yc + d * uy;
% Tick line endpoints
xt1 = xt - 0.5 * tick_length * perp_ux;
yt1 = yt - 0.5 * tick_length * perp_uy;
xt2 = xt + 0.5 * tick_length * perp_ux;
yt2 = yt + 0.5 * tick_length * perp_uy;
% Draw tick
plot([xt1 xt2], [yt1 yt2], '--', 'Color', tick_color, 'LineWidth', 1);
% Label: centered at tick, offset slightly along diagonal
if d ~= 0
text(xt, yt, sprintf('%+d', d), ...
'Color', tick_color, ...
'FontSize', font_size, ...
'HorizontalAlignment', 'center', ...
'VerticalAlignment', 'bottom', ...
'Rotation', atan2d(dy, dx));
end
end
end
function drawPSOverlays(kx, ky, r_min, r_max)
% drawFFTOverlays - Draw overlays on existing FFT plot:
% - Radial lines every 30°
% - Annular highlight with white (upper half) and gray (lower half) circles between r_min and r_max
% - Horizontal white bands at ky=0 in annulus region
% - Scale ticks and labels every 1 μm¹ along each radial line
%
% Inputs:
% kx, ky - reciprocal space vectors (μm¹)
% r_min - inner annulus radius offset index (integer)
% r_max - outer annulus radius offset index (integer)
%
% Example:
% hold on;
% drawFFTOverlays(kx, ky, 10, 30);
hold on
% === Overlay Radial Lines + Scales ===
[kx_grid, ky_grid] = meshgrid(kx, ky);
[~, kr_grid] = cart2pol(kx_grid, ky_grid); % kr_grid in μm¹
max_kx = max(kx);
max_ky = max(ky);
for angle = 0 : pi/6 : pi
x_line = [0, max_kx] * cos(angle);
y_line = [0, max_ky] * sin(angle);
% Plot radial lines
plot(x_line, y_line, '--', 'Color', [0.5 0.5 0.5], 'LineWidth', 1.2);
plot(x_line, -y_line, '--', 'Color', [0.5 0.5 0.5], 'LineWidth', 1.2);
% Draw scale ticks along positive radial line
drawTicksAlongLine(0, 0, x_line(2), y_line(2));
% Draw scale ticks along negative radial line (reflect y)
drawTicksAlongLine(0, 0, x_line(2), -y_line(2));
end
% === Overlay Annular Highlight: White (r_min to r_max), Gray elsewhere ===
theta_full = linspace(0, 2*pi, 500);
center_x = ceil(size(kr_grid, 2) / 2);
center_y = ceil(size(kr_grid, 1) / 2);
k_min = kr_grid(center_y, center_x + r_min);
k_max = kr_grid(center_y, center_x + r_max);
% Upper half: white dashed circles
x1_upper = k_min * cos(theta_full(theta_full <= pi));
y1_upper = k_min * sin(theta_full(theta_full <= pi));
x2_upper = k_max * cos(theta_full(theta_full <= pi));
y2_upper = k_max * sin(theta_full(theta_full <= pi));
plot(x1_upper, y1_upper, 'k--', 'LineWidth', 1.2);
plot(x2_upper, y2_upper, 'k--', 'LineWidth', 1.2);
% Lower half: gray dashed circles
x1_lower = k_min * cos(theta_full(theta_full > pi));
y1_lower = k_min * sin(theta_full(theta_full > pi));
x2_lower = k_max * cos(theta_full(theta_full > pi));
y2_lower = k_max * sin(theta_full(theta_full > pi));
plot(x1_lower, y1_lower, '--', 'Color', [0.5 0.5 0.5], 'LineWidth', 1.0);
plot(x2_lower, y2_lower, '--', 'Color', [0.5 0.5 0.5], 'LineWidth', 1.0);
% === Highlight horizontal band across k_y = 0 ===
x_vals = kx;
xW1 = x_vals((x_vals >= -k_max) & (x_vals < -k_min));
xW2 = x_vals((x_vals > k_min) & (x_vals <= k_max));
plot(xW1, zeros(size(xW1)), 'k--', 'LineWidth', 1.2);
plot(xW2, zeros(size(xW2)), 'k--', 'LineWidth', 1.2);
hold off
% --- Nested helper function to draw ticks along a radial line ---
function drawTicksAlongLine(x_start, y_start, x_end, y_end)
% Tick parameters
tick_spacing = 1; % spacing between ticks in μm¹
tick_length = 0.05 * sqrt((x_end - x_start)^2 + (y_end - y_start)^2); % relative tick length
line_color = [0.5 0.5 0.5];
tick_color = [0.5 0.5 0.5];
font_size = 8;
% Vector along the line
dx = x_end - x_start;
dy = y_end - y_start;
L = sqrt(dx^2 + dy^2);
ux = dx / L;
uy = dy / L;
% Perpendicular vector for ticks
perp_ux = -uy;
perp_uy = ux;
% Number of ticks (from 0 up to max length)
n_ticks = floor(L / tick_spacing);
for i = 1:n_ticks
% Position of tick along the line
xt = x_start + i * tick_spacing * ux;
yt = y_start + i * tick_spacing * uy;
% Tick endpoints
xt1 = xt - 0.5 * tick_length * perp_ux;
yt1 = yt - 0.5 * tick_length * perp_uy;
xt2 = xt + 0.5 * tick_length * perp_ux;
yt2 = yt + 0.5 * tick_length * perp_uy;
% Draw tick
plot([xt1 xt2], [yt1 yt2], '-', 'Color', tick_color, 'LineWidth', 1);
% Label with distance (integer)
text(xt, yt, sprintf('%d', i), ...
'Color', tick_color, ...
'FontSize', font_size, ...
'HorizontalAlignment', 'center', ...
'VerticalAlignment', 'bottom', ...
'Rotation', atan2d(dy, dx));
end
end
end
function [optrefimages] = removefringesInImage(absimages, refimages, bgmask)
% removefringesInImage - Fringe removal and noise reduction from absorption images.
% Creates an optimal reference image for each absorption image in a set as
% a linear combination of reference images, with coefficients chosen to
% minimize the least-squares residuals between each absorption image and
% the optimal reference image. The coefficients are obtained by solving a
% linear set of equations using matrix inverse by LU decomposition.
%
% Application of the algorithm is described in C. F. Ockeloen et al, Improved
% detection of small atom numbers through image processing, arXiv:1007.2136 (2010).
%
% Syntax:
% [optrefimages] = removefringesInImage(absimages,refimages,bgmask);
%
% Required inputs:
% absimages - Absorption image data,
% typically 16 bit grayscale images
% refimages - Raw reference image data
% absimages and refimages are both cell arrays containing
% 2D array data. The number of refimages can differ from the
% number of absimages.
%
% Optional inputs:
% bgmask - Array specifying background region used,
% 1=background, 0=data. Defaults to all ones.
% Outputs:
% optrefimages - Cell array of optimal reference images,
% equal in size to absimages.
%
% Dependencies: none
%
% Authors: Shannon Whitlock, Caspar Ockeloen
% Reference: C. F. Ockeloen, A. F. Tauschinsky, R. J. C. Spreeuw, and
% S. Whitlock, Improved detection of small atom numbers through
% image processing, arXiv:1007.2136
% Email:
% May 2009; Last revision: 11 August 2010
% Process inputs
% Set variables, and flatten absorption and reference images
nimgs = size(absimages,3);
nimgsR = size(refimages,3);
xdim = size(absimages(:,:,1),2);
ydim = size(absimages(:,:,1),1);
R = single(reshape(refimages,xdim*ydim,nimgsR));
A = single(reshape(absimages,xdim*ydim,nimgs));
optrefimages=zeros(size(absimages)); % preallocate
if not(exist('bgmask','var')); bgmask=ones(ydim,xdim); end
k = find(bgmask(:)==1); % Index k specifying background region
% Ensure there are no duplicate reference images
% R=unique(R','rows')'; % comment this line if you run out of memory
% Decompose B = R*R' using singular value or LU decomposition
[L,U,p] = lu(R(k,:)'*R(k,:),'vector'); % LU decomposition
for j=1:nimgs
b=R(k,:)'*A(k,j);
% Obtain coefficients c which minimise least-square residuals
lower.LT = true; upper.UT = true;
c = linsolve(U,linsolve(L,b(p,:),lower),upper);
% Compute optimised reference image
optrefimages(:,:,j)=reshape(R*c,[ydim xdim]);
end
end

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%% Evolve across a second-order-like transition
clear; clc;
N_params = 50;
N_reps = 50;
alpha_values = linspace(0, 45, N_params);
all_data = cell(1, N_params);
% Transition control
alpha_start = 5; % where sigma starts changing
alpha_widen_end = 15; % when sigma finishes first change
alpha_shift_start = 15; % when mean starts shifting
alpha_end = 40; % when mean finishes shifting and sigma narrows
mu_start = 1.2; % high initial mean
mu_end = 0.2; % low final mean
sigma_start = 0.25; % wide std at start
sigma_mid = 0.15; % mid-range std in middle
sigma_end = 0.07; % narrow std at end
max_skew = 5; % peak skew strength
for i = 1:N_params
alpha = alpha_values(i);
% === Sigma evolution (variance large -> small) ===
if alpha < alpha_start
sigma = sigma_start; % wide at start
elseif alpha < alpha_widen_end
% Smooth transition from wide to mid
t_sigma = (alpha - alpha_start) / (alpha_widen_end - alpha_start);
sigma = sigma_start * (1 - t_sigma) + sigma_mid * t_sigma;
elseif alpha < alpha_end
% Smooth transition from mid to narrow
t_sigma = (alpha - alpha_widen_end) / (alpha_end - alpha_widen_end);
sigma = sigma_mid * (1 - t_sigma) + sigma_end * t_sigma;
else
sigma = sigma_end; % narrow at end
end
% === Mean evolution ===
if alpha < alpha_shift_start
mu = mu_start; % fixed at high initially
elseif alpha <= alpha_end
% Smooth cosine shift
t_mu = (alpha - alpha_shift_start) / (alpha_end - alpha_shift_start);
smooth_t_mu = (1 - cos(pi * t_mu)) / 2;
mu = mu_start * (1 - smooth_t_mu) + mu_end * smooth_t_mu;
else
mu = mu_end;
end
% === Skew evolution ===
if alpha < alpha_end
t_skew = (alpha - alpha_start) / (alpha_end - alpha_start);
skew_strength = max_skew * (1 - t_skew); % fade out
else
skew_strength = 0;
end
% Generate data
if abs(skew_strength) < 1e-2
data = normrnd(mu, sigma, [N_reps, 1]);
else
data = skewnormrnd(mu, sigma, skew_strength, N_reps);
end
all_data{i} = data;
% Cumulants
kappa = computeCumulants(data, 6);
mean_vals(i) = kappa(1);
var_vals(i) = kappa(2);
skew_vals(i) = kappa(3);
kappa4_vals(i) = kappa(4);
kappa5_vals(i) = kappa(5);
kappa6_vals(i) = kappa(6);
end
%% Evolve across a first-order-like transition
% First-order-like distribution evolution with significant bimodality
clear; clc;
N_params = 50;
N_reps = 50;
alpha_values = linspace(0, 45, N_params);
all_data = cell(1, N_params);
% Define transition regions
skewed_start = 10;
bimodal_start = 20;
bimodal_end = 35;
final_narrow_start = 40;
% Peak positions and widths
mu_high = 1.2; % Initial metastable peak
mu_low = 0.2; % Final stable peak
mu_new_peak = 0.8; % New peak appears slightly lower
sigma_initial = 0.08;
for i = 1:N_params
alpha = alpha_values(i);
if alpha < skewed_start
% Region I: Narrow unimodal at high mean
data = normrnd(mu_high, sigma_initial, [N_reps, 1]);
elseif alpha < bimodal_start
% Region II: Slightly skewed
t_skew = (alpha - skewed_start) / (bimodal_start - skewed_start);
mu = mu_high - 0.15 * t_skew;
sigma = sigma_initial + 0.02 * t_skew;
skew_strength = 3 * t_skew;
data = skewnormrnd(mu, sigma, skew_strength, N_reps);
elseif alpha < bimodal_end
% Region III: Bimodal with fixed or slowly drifting peak positions
t = (alpha - bimodal_start) / (bimodal_end - bimodal_start); % t in [0, 1]
% Increased separation between peaks
drift_amount = 0.3; % larger = more drift toward final mean
sep_offset = 0.25; % larger = more initial separation between peaks
% Peaks start separated and move toward mu_low
mu1 = mu_high * (1 - t)^drift_amount + mu_low * (1 - (1 - t)^drift_amount); % Right peak drifts to left
mu2 = (mu_new_peak - sep_offset) * (1 - t)^drift_amount + mu_low * (1 - (1 - t)^drift_amount); % Left peak moves slightly
sigma1 = sigma_initial + 0.02 * (1 - abs(0.5 - t) * 2);
sigma2 = sigma1;
% Weight shift: right peak dies out, left peak grows
w2 = 0.5 + 0.5 * t; % left peak grows: 0.5 1
w1 = 1 - w2; % right peak fades: 0.5 0
N1 = round(N_reps * w1);
N2 = N_reps - N1;
mode1 = normrnd(mu1, sigma1, [N1, 1]);
mode2 = normrnd(mu2, sigma2, [N2, 1]);
data = [mode1; mode2];
data = data(randperm(length(data)));
else
% Region IV: Final stable low-mean Gaussian
data = normrnd(mu_low, sigma_initial, [N_reps, 1]);
end
% Store data and compute cumulants
all_data{i} = data;
kappa = computeCumulants(data, 6);
mean_vals(i) = kappa(1);
var_vals(i) = kappa(2);
skew_vals(i) = kappa(3);
kappa4_vals(i) = kappa(4);
kappa5_vals(i) = kappa(5);
kappa6_vals(i) = kappa(6);
end
%% === Compute 2D PDF heatmap: f(x, alpha) ===
x_grid = linspace(0.0, 1.8, 200); % max[g²] values on y-axis
pdf_matrix = zeros(numel(x_grid), N_params); % Now: rows = y, columns = alpha
for i = 1:N_params
data = all_data{i};
f = ksdensity(data, x_grid, 'Bandwidth', 0.025);
pdf_matrix(:, i) = f; % Transpose for y-axis to be vertical
end
% === Plot PDF vs. alpha heatmap ===
figure(2); clf;
set(gcf, 'Color', 'w', 'Position',[100 100 950 750])
imagesc(alpha_values, x_grid, pdf_matrix);
set(gca, 'YDir', 'normal'); % Flip y-axis to normal orientation
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', 'FontSize', 14);
ylabel('$\mathrm{max}[g^{(2)}]$', 'Interpreter', 'latex', 'FontSize', 14);
title('Evolving PDF of $\mathrm{max}[g^{(2)}]$', ...
'Interpreter', 'latex', 'FontSize', 16);
colormap(Colormaps.coolwarm()); % More aesthetic than default
colorbar;
c = colorbar;
ylabel(c, 'PDF', 'FontSize', 14, 'Interpreter', 'latex');
set(gca, 'FontSize', 14);
%% Animate evolving distribution and cumulant value
figure(1); clf;
set(gcf, 'Color', 'w', 'Position',[100 100 1300 750])
for i = 1:N_params
clf;
% PDF
subplot(1,2,1); cla; hold on;
data = all_data{i};
% Plot histogram with normalized PDF
histogram(data, 'Normalization', 'pdf', 'BinWidth', 0.03, ...
'FaceColor', [0.3 0.5 0.8], 'EdgeColor', 'k', 'FaceAlpha', 0.6);
title(sprintf('Histogram at $\\alpha = %.1f^\\circ$', alpha_values(i)), ...
'Interpreter', 'latex', 'FontSize', 16);
xlabel('$\mathrm{max}[g^{(2)}]$', 'Interpreter', 'latex', 'FontSize', 14);
ylabel('PDF', 'FontSize', 14);
set(gca, 'FontSize', 12); grid on;
xlim([0.0, 2.0]);
% Cumulant evolution
subplot(1,2,2); hold on;
plot(alpha_values(1:i), kappa4_vals(1:i), 'bo-', 'LineWidth', 2);
title('Binder Cumulant Tracking', 'Interpreter', 'latex', 'FontSize', 16);
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', 'FontSize', 14);
ylabel('$\kappa_4$', 'Interpreter', 'latex', 'FontSize', 14);
xlim([0, 45]); grid on;
set(gca, 'FontSize', 12);
pause(0.3);
end
%% === Plotting ===
figure(1)
set(gcf, 'Color', 'w', 'Position', [100 100 950 750])
t = tiledlayout(2, 2, 'TileSpacing', 'compact', 'Padding', 'compact');
scan_vals = alpha_values; % your parameter sweep values
% Define font style for consistency
axis_fontsize = 14;
label_fontsize = 16;
title_fontsize = 16;
% 1. Mean with error bars (if you have error data, else just plot)
% If no error, replace errorbar with plot or omit error data
% For now, no error bars assumed
nexttile;
plot(scan_vals, mean_vals, 'o-', 'LineWidth', 1.5, 'MarkerSize', 6);
title('Mean', 'FontSize', title_fontsize, 'Interpreter', 'latex');
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', 'FontSize', label_fontsize);
ylabel('$\kappa_1$', 'Interpreter', 'latex', 'FontSize', label_fontsize);
set(gca, 'FontSize', axis_fontsize);
grid on;
% 2. Variance
nexttile;
plot(scan_vals, var_vals, 's-', 'LineWidth', 1.5, 'MarkerSize', 6);
title('Variance', 'FontSize', title_fontsize, 'Interpreter', 'latex');
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', 'FontSize', label_fontsize);
ylabel('$\kappa_2$', 'Interpreter', 'latex', 'FontSize', label_fontsize);
set(gca, 'FontSize', axis_fontsize);
grid on;
% 3. Skewness
nexttile;
plot(scan_vals, skew_vals, 'd-', 'LineWidth', 1.5, 'MarkerSize', 6);
title('Skewness', 'FontSize', title_fontsize, 'Interpreter', 'latex');
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', 'FontSize', label_fontsize);
ylabel('$\kappa_3$', 'Interpreter', 'latex', 'FontSize', label_fontsize);
set(gca, 'FontSize', axis_fontsize);
grid on;
% 4. Binder Cumulant
nexttile;
plot(scan_vals, kappa4_vals, '^-', 'LineWidth', 1.5, 'MarkerSize', 6);
title('Binder Cumulant', 'FontSize', title_fontsize, 'Interpreter', 'latex');
xlabel('$\alpha$ (degrees)', 'Interpreter', 'latex', 'FontSize', label_fontsize);
ylabel('$\kappa_4$', 'Interpreter', 'latex', 'FontSize', label_fontsize);
set(gca, 'FontSize', axis_fontsize);
grid on;
% Super title (you can customize the string)
sgtitle('Cumulants of a simulated evolving distribution', ...
'FontWeight', 'bold', 'FontSize', 18, 'Interpreter', 'latex');
%% === Helper: Cumulant Calculation ===
function kappa = computeCumulants(data, max_order)
data = data(:);
mu = mean(data);
c = zeros(1, max_order);
centered = data - mu;
for n = 1:max_order
c(n) = mean(centered.^n);
end
kappa = zeros(1, max_order);
kappa(1) = mu;
kappa(2) = c(2);
kappa(3) = c(3);
kappa(4) = c(4) - 3*c(2)^2;
kappa(5) = c(5) - 10*c(3)*c(2);
kappa(6) = c(6) - 15*c(4)*c(2) - 10*c(3)^2 + 30*c(2)^3;
end
%% === Helper: Skewed Normal Distribution ===
function x = skewnormrnd(mu, sigma, alpha, n)
% Skew-normal using Azzalini's method
delta = alpha / sqrt(1 + alpha^2);
u0 = randn(n,1);
v = randn(n,1);
u1 = delta * u0 + sqrt(1 - delta^2) * v;
x = mu + sigma * u1 .* sign(u0);
end

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%% Main script: Sweep different parameter pairs
% Default parameters
defaults.mu1 = 0.5;
defaults.mu2 = 1.0;
defaults.sigma1 = 0.1;
defaults.sigma2 = 0.1;
defaults.weight1 = 0.5;
% Parameter pair definitions
%{
param_pairs = {
'mu1', linspace(0.7, 1.0, 40), ...
'mu2', linspace(1.0, 1.3, 40);
'mu1', linspace(0.7, 1.0, 40), ...
'weight1', linspace(0.2, 0.8, 40);
'sigma1', linspace(0.05, 0.2, 40), ...
'sigma2', linspace(0.05, 0.2, 40);
'mu1', linspace(0.7, 1.0, 40), ...
'sigma1', linspace(0.05, 0.2, 40);
'mu2', linspace(1.0, 1.3, 40), ...
'weight1', linspace(0.2, 0.8, 40);
};
%}
param_pairs = {
'mu1', linspace(0.1, 1.5, 40), ...
'mu2', linspace(0.1, 1.5, 40);
};
% Cumulant index to visualize (2=variance, 3=skewness, 4=kurtosis)
cumulant_to_plot = 4;
% Run sweep for each pair
for i = 1:size(param_pairs,1)
param1_name = param_pairs{i,1};
param1_vals = param_pairs{i,2};
param2_name = param_pairs{i,3};
param2_vals = param_pairs{i,4};
fprintf('Sweeping %s and %s...\n', param1_name, param2_name);
Z = sweepBimodalCumulants(param1_name, param1_vals, ...
param2_name, param2_vals, ...
defaults, cumulant_to_plot);
end
%%
% Parameters
N_total = 10000;
mu1 = 0.5;
sigma1 = 0.1;
mu2 = 1.0;
sigma2 = 0.1;
weight1 = 0.7;
% Generate data
data = generateBimodalDistribution(N_total, mu1, mu2, sigma1, sigma2, weight1);
% Plot histogram
figure(3);
clf
set(gcf, 'Color', 'w', 'Position', [100 100 950 750]);
histogram(data, 'Normalization', 'pdf', 'EdgeColor', 'none', 'FaceAlpha', 0.5);
hold on;
% Overlay smooth density estimate
[xi, f] = ksdensity(data);
plot(f, xi, 'r-', 'LineWidth', 2);
% Labels and title
xlabel('Value');
ylabel('Probability Density');
legend('Histogram', 'Smoothed Density');
grid on;
%%
N = size(Z, 1);
main_diag_values = diag(Z);
anti_diag_values = diag(flipud(Z));
param1_diag_main = param1_vals;
param2_diag_main = param2_vals;
param1_diag_anti = param1_vals;
param2_diag_anti = flip(param2_vals);
% For example, plot the main diagonal cumulants:
figure(4);
set(gcf, 'Color', 'w', 'Position', [100 100 950 750]);
plot(1:N, main_diag_values, '-o');
xlabel('Index along diagonal');
ylabel('$\kappa_4$', 'Interpreter', 'latex');
title('$\kappa_4$ along anti-diagonal', 'Interpreter', 'latex');
% Plot anti-diagonal cumulants:
figure(5);
set(gcf, 'Color', 'w', 'Position', [100 100 950 750]);
plot(1:N, anti_diag_values, '-o');
xlabel('Index along anti-diagonal');
ylabel('$\kappa_4$', 'Interpreter', 'latex');
title('$\kappa_4$ along anti-diagonal', 'Interpreter', 'latex');
%% === Helper: Bimodal Distribution ===
function data = generateBimodalDistribution(N_total, mu1, mu2, sigma1, sigma2, weight1)
%GENERATEBIMODALDISTRIBUTION Generates a single bimodal distribution.
%
% data = generateBimodalDistribution(N_total, mu1, mu2, sigma1, sigma2, weight1)
%
% Inputs:
% N_total - total number of samples
% mu1, mu2 - means of the two modes
% sigma1, sigma2 - standard deviations of the two modes
% weight1 - fraction of samples from mode 1 (between 0 and 1)
%
% Output:
% data - shuffled samples from the bimodal distribution
% Validate weight
weight1 = min(max(weight1, 0), 1);
weight2 = 1 - weight1;
% Determine number of samples for each mode
N1 = round(N_total * weight1);
N2 = N_total - N1;
% Generate samples
mode1_samples = normrnd(mu1, sigma1, [N1, 1]);
mode2_samples = normrnd(mu2, sigma2, [N2, 1]);
% Combine and shuffle
data = [mode1_samples; mode2_samples];
data = data(randperm(length(data)));
end
%% === Helper: Cumulant Calculation ===
function kappa = computeCumulants(data, max_order)
data = data(:);
mu = mean(data);
centered = data - mu;
% Preallocate
c = zeros(1, max_order);
kappa = zeros(1, max_order);
% Compute central moments up to max_order
for n = 1:max_order
c(n) = mean(centered.^n);
end
% Assign cumulants based on available order
if max_order >= 1, kappa(1) = mu; end
if max_order >= 2, kappa(2) = c(2); end
if max_order >= 3, kappa(3) = c(3); end
if max_order >= 4, kappa(4) = c(4) - 3*c(2)^2; end
if max_order >= 5, kappa(5) = c(5) - 10*c(3)*c(2); end
if max_order >= 6
kappa(6) = c(6) - 15*c(4)*c(2) - 10*c(3)^2 + 30*c(2)^3;
end
end
%% === Helper: Cumulant Calculation ===
function Z = sweepBimodalCumulants(param1_name, param1_vals, ...
param2_name, param2_vals, ...
fixed_params, ...
cumulant_index)
%SWEEPBIMODALCUMULANTS Sweep 2 parameters and return a chosen cumulant.
%
% Z = sweepBimodalCumulants(...)
% Returns a matrix Z of cumulant values at each grid point.
% Setup grid
[P1, P2] = meshgrid(param1_vals, param2_vals);
Z = zeros(size(P1));
N_samples = 1000;
maxOrder = max(4, cumulant_index);
for i = 1:numel(P1)
% Copy fixed parameters
params = fixed_params;
% Override swept parameters
params.(param1_name) = P1(i);
params.(param2_name) = P2(i);
% Generate and compute cumulants
data = generateBimodalDistribution(N_samples, ...
params.mu1, params.mu2, ...
params.sigma1, params.sigma2, ...
params.weight1);
kappa = computeCumulants(data, maxOrder);
Z(i) = kappa(cumulant_index);
end
% Plot full heatmap
figure;
set(gcf, 'Color', 'w', 'Position', [100 100 950 750]);
imagesc(param1_vals, param2_vals, Z);
set(gca, 'YDir', 'normal');
xlabel(param1_name);
ylabel(param2_name);
title(['Cumulant \kappa_', num2str(cumulant_index)]);
colorbar;
axis tight;
% Optional binary colormap (red = 0, blue = <0)
figure;
set(gcf, 'Color', 'w', 'Position', [100 100 950 750]);
imagesc(param1_vals, param2_vals, Z);
set(gca, 'YDir', 'normal');
xlabel(param1_name);
ylabel(param2_name);
title(['Binary color split of \kappa_', num2str(cumulant_index)]);
clim([-1 1]);
colormap([0 0 1; 1 0 0]); % Blue (neg), Red (pos & zero)
colorbar;
axis tight;
end