767 lines
26 KiB
Matlab
767 lines
26 KiB
Matlab
% === Parameters ===
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baseFolder = '//DyLabNAS/Data/TwoDGas/2025/04/';
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dates = ["01", "02"];
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runs = {
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["0059", "0060", "0061"],
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["0007", "0008", "0009", "0010", "0011"]
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};
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scan_groups = 0:10:50;
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scan_parameter = 'rot_mag_fin_pol_angle';
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cam = 5;
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% Image cropping and alignment
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angle = 0;
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center = [1285, 2100];
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span = [200, 200];
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fraction = [0.1, 0.1];
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% Imaging and calibration parameters
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pixel_size = 5.86e-6; % in meters
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magnification = 23.94;
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removeFringes = false;
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ImagingMode = 'LowIntensity';
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PulseDuration = 5e-6;
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% Optional visualization / zooming
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options.zoom_size = 50;
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% Optional flags or settings struct
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skipUnshuffling = false;
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skipPreprocessing = true;
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skipMasking = true;
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skipIntensityThresholding = true;
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skipBinarization = true;
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groupList = ["/images/MOT_3D_Camera/in_situ_absorption", "/images/ODT_1_Axis_Camera/in_situ_absorption", ...
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"/images/ODT_2_Axis_Camera/in_situ_absorption", "/images/Horizontal_Axis_Camera/in_situ_absorption", ...
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"/images/Vertical_Axis_Camera/in_situ_absorption"];
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%%
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allData = {}; % now a growing list of structs per B field
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dataCounter = 1;
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for i = 1:length(dates)
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dateStr = dates(i);
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runList = runs{i};
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for j = 1:length(runList)
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folderPath = fullfile(baseFolder, dateStr, runList{j});
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filePattern = fullfile(folderPath, '*.h5');
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files = dir(filePattern);
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refimages = zeros(span(1) + 1, span(2) + 1, length(files));
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absimages = zeros(span(1) + 1, span(2) + 1, length(files));
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for k = 1 : length(files)
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baseFileName = files(k).name;
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fullFileName = fullfile(files(k).folder, baseFileName);
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fprintf(1, 'Now reading %s\n', fullFileName);
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atm_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/atoms")), angle));
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bkg_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/background")), angle));
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dark_img = double(imrotate(h5read(fullFileName, append(groupList(cam), "/dark")), angle));
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refimages(:,:,k) = subtractBackgroundOffset(cropODImage(bkg_img, center, span), fraction)';
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absimages(:,:,k) = subtractBackgroundOffset(cropODImage(calculateODImage(atm_img, bkg_img, dark_img, ImagingMode, PulseDuration), center, span), fraction)';
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end
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% ===== Fringe removal =====
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if removeFringes
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optrefimages = removefringesInImage(absimages, refimages);
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absimages_fringe_removed = absimages(:, :, :) - optrefimages(:, :, :);
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nimgs = size(absimages_fringe_removed,3);
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od_imgs = cell(1, nimgs);
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for k = 1:nimgs
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od_imgs{k} = absimages_fringe_removed(:, :, k);
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end
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else
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nimgs = size(absimages(:, :, :),3);
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od_imgs = cell(1, nimgs);
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for k = 1:nimgs
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od_imgs{k} = absimages(:, :, k);
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end
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end
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%% ===== Get rotation angles =====
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scan_parameter_values = zeros(1, length(files));
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% Get information about the '/globals' group
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for k = 1 : length(files)
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baseFileName = files(k).name;
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fullFileName = fullfile(files(k).folder, baseFileName);
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info = h5info(fullFileName, '/globals');
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for i = 1:length(info.Attributes)
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if strcmp(info.Attributes(i).Name, scan_parameter)
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if strcmp(scan_parameter, 'rot_mag_fin_pol_angle')
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scan_parameter_values(k) = 180 - info.Attributes(i).Value;
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else
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scan_parameter_values(k) = info.Attributes(i).Value;
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end
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end
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if strcmp(info.Attributes(i).Name, "rot_mag_field")
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B = info.Attributes(i).Value;
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end
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end
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end
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% ===== Unshuffle if necessary to do so =====
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if ~skipUnshuffling
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n_values = length(scan_groups);
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n_total = length(scan_parameter_values);
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% Infer number of repetitions
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n_reps = n_total / n_values;
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% Preallocate ordered arrays
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ordered_scan_values = zeros(1, n_total);
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ordered_od_imgs = cell(1, n_total);
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counter = 1;
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for rep = 1:n_reps
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for val = scan_groups
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% Find the next unused match for this val
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idx = find(scan_parameter_values == val, 1, 'first');
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% Assign and remove from list to avoid duplicates
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ordered_scan_values(counter) = scan_parameter_values(idx);
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ordered_od_imgs{counter} = od_imgs{idx};
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% Mark as used by removing
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scan_parameter_values(idx) = NaN; % NaN is safe since original values are 0:5:45
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od_imgs{idx} = []; % empty cell so it won't be matched again
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counter = counter + 1;
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end
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end
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% Now assign back
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scan_parameter_values = ordered_scan_values;
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od_imgs = ordered_od_imgs;
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end
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% === Reshape ===
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od_imgs_reshaped = reshape(od_imgs, [length(scan_groups), n_reps]);
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% === Store ===
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allData{dataCounter} = struct(...
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'B', B, ...
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'theta_vals', scan_groups, ...
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'od_imgs', od_imgs_reshaped ...
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);
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dataCounter = dataCounter + 1;
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end
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end
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%% === % Plot PD - 1st rep of each θ per B-field ===
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[theta_vals, ~, idx] = unique(scan_parameter_values);
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nB = numel(allData);
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nTheta = numel(theta_vals);
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% Select every 2nd B-field index
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idxToPlot = 1:2:nB; % indices 1, 3, 5, ...
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% Update number of B-fields to plot
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nB_new = numel(idxToPlot);
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figure(101); clf;
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% Make the figure wider to fit the colorbar comfortably
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set(gcf, 'Position', [100, 100, 1300, 800]);
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% Create tiled layout with some right padding to reserve space for colorbar
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t = tiledlayout(nB_new, nTheta, 'TileSpacing', 'compact', 'Padding', 'compact');
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font = 'Bahnschrift';
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allAxes = gobjects(nB_new, nTheta);
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for new_i = 1:nB_new
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i = idxToPlot(new_i); % original index in allData
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data = allData{i};
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for j = 1:nTheta
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ax = nexttile((new_i-1)*nTheta + j);
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allAxes(new_i,j) = ax;
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od = data(j).od_imgs;
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imagesc(od, 'Parent', ax);
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set(ax, 'YDir', 'normal');
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axis(ax, 'image');
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ax.XTick = [];
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ax.YTick = [];
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colormap(ax, Colormaps.inferno());
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end
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end
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% Use colorbar associated with the last image tile
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cb = colorbar('Location', 'eastoutside');
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cb.Layout.Tile = 'east'; % Attach it to the layout edge
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cb.FontName = font;
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cb.FontSize = 18;
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cb.Label.FontSize = 20;
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cb.Label.Rotation = 90;
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cb.Label.VerticalAlignment = 'bottom';
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cb.Label.HorizontalAlignment = 'center';
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cb.Direction = 'normal'; % Ensure ticks go bottom-to-top
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% Add x and y tick labels along bottom and left
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% Use bottom row for θ ticks
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for j = 1:nTheta
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ax = allAxes(end, j);
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ax.XTick = size(od,2)/2;
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ax.XTickLabel = sprintf('%d°', theta_vals(j));
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ax.XTickLabelRotation = 0;
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ax.FontName = font;
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ax.FontSize = 20;
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end
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% Use first column for B ticks (only the plotted subset)
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for new_i = 1:nB_new
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i = idxToPlot(new_i);
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ax = allAxes(new_i, 1);
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ax.YTick = size(od,1)/2;
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ax.YTickLabel = sprintf('%.2f G', allData{i}(1).B);
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ax.FontName = font;
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ax.FontSize = 20;
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end
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%% Helper Functions
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function [IMGFFT, IMGPR] = computeFourierTransform(I, skipPreprocessing, skipMasking, skipIntensityThresholding, skipBinarization)
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% computeFourierSpectrum - Computes the 2D Fourier power spectrum
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% of binarized and enhanced lattice image features, with optional central mask.
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%
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% Inputs:
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% I - Grayscale or RGB image matrix
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%
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% Output:
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% F_mag - 2D Fourier power spectrum (shifted)
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if ~skipPreprocessing
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% Preprocessing: Denoise
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filtered = imgaussfilt(I, 10);
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IMGPR = I - filtered; % adjust sigma as needed
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else
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IMGPR = I;
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end
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if ~skipMasking
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[rows, cols] = size(IMGPR);
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[X, Y] = meshgrid(1:cols, 1:rows);
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% Elliptical mask parameters
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cx = cols / 2;
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cy = rows / 2;
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% Shifted coordinates
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x = X - cx;
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y = Y - cy;
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% Ellipse semi-axes
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rx = 0.4 * cols;
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ry = 0.2 * rows;
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% Rotation angle in degrees -> radians
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theta_deg = 30; % Adjust as needed
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theta = deg2rad(theta_deg);
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% Rotated ellipse equation
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cos_t = cos(theta);
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sin_t = sin(theta);
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x_rot = (x * cos_t + y * sin_t);
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y_rot = (-x * sin_t + y * cos_t);
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ellipseMask = (x_rot.^2) / rx^2 + (y_rot.^2) / ry^2 <= 1;
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% Apply cutout mask
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IMGPR = IMGPR .* ellipseMask;
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end
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if ~skipIntensityThresholding
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% Apply global intensity threshold mask
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intensity_thresh = 0.20;
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intensity_mask = IMGPR > intensity_thresh;
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IMGPR = IMGPR .* intensity_mask;
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end
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if ~skipBinarization
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% Adaptive binarization and cleanup
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IMGPR = imbinarize(IMGPR, 'adaptive', 'Sensitivity', 0.0);
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IMGPR = imdilate(IMGPR, strel('disk', 2));
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IMGPR = imerode(IMGPR, strel('disk', 1));
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IMGPR = imfill(IMGPR, 'holes');
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F = fft2(double(IMGPR)); % Compute 2D Fourier Transform
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IMGFFT = abs(fftshift(F))'; % Shift zero frequency to center
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else
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F = fft2(double(IMGPR)); % Compute 2D Fourier Transform
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IMGFFT = abs(fftshift(F))'; % Shift zero frequency to center
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end
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end
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function [k_rho_vals, S_radial] = computeRadialSpectralDistribution(IMGFFT, kx, ky, thetamin, thetamax, num_bins)
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% IMGFFT : 2D FFT image (fftshifted and cropped)
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% kx, ky : 1D physical wavenumber axes [μm⁻¹] matching FFT size
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% thetamin : Minimum angle (in radians)
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% thetamax : Maximum angle (in radians)
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% num_bins : Number of radial bins
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[KX, KY] = meshgrid(kx, ky);
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K_rho = sqrt(KX.^2 + KY.^2);
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Theta = atan2(KY, KX);
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if thetamin < thetamax
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angle_mask = (Theta >= thetamin) & (Theta <= thetamax);
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else
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angle_mask = (Theta >= thetamin) | (Theta <= thetamax);
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end
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power_spectrum = abs(IMGFFT).^2;
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r_min = min(K_rho(angle_mask));
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r_max = max(K_rho(angle_mask));
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r_edges = linspace(r_min, r_max, num_bins + 1);
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k_rho_vals = 0.5 * (r_edges(1:end-1) + r_edges(2:end));
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S_radial = zeros(1, num_bins);
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for i = 1:num_bins
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r_low = r_edges(i);
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r_high = r_edges(i + 1);
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radial_mask = (K_rho >= r_low) & (K_rho < r_high);
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full_mask = radial_mask & angle_mask;
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S_radial(i) = sum(power_spectrum(full_mask));
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end
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end
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function [theta_vals, S_theta] = computeAngularSpectralDistribution(IMGFFT, r_min, r_max, num_bins, threshold, sigma, windowSize)
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% Apply threshold to isolate strong peaks
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IMGFFT(IMGFFT < threshold) = 0;
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% Prepare polar coordinates
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[ny, nx] = size(IMGFFT);
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[X, Y] = meshgrid(1:nx, 1:ny);
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cx = ceil(nx/2);
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cy = ceil(ny/2);
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R = sqrt((X - cx).^2 + (Y - cy).^2);
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Theta = atan2(Y - cy, X - cx); % range [-pi, pi]
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% Choose radial band
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radial_mask = (R >= r_min) & (R <= r_max);
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% Initialize angular structure factor
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S_theta = zeros(1, num_bins);
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theta_vals = linspace(0, pi, num_bins);
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% Loop through angle bins
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for i = 1:num_bins
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angle_start = (i-1) * pi / num_bins;
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angle_end = i * pi / num_bins;
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angle_mask = (Theta >= angle_start & Theta < angle_end);
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bin_mask = radial_mask & angle_mask;
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fft_angle = IMGFFT .* bin_mask;
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S_theta(i) = sum(sum(abs(fft_angle).^2));
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end
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% Smooth using either Gaussian or moving average
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if exist('sigma', 'var') && ~isempty(sigma)
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% Gaussian convolution
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half_width = ceil(3 * sigma);
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x = -half_width:half_width;
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gauss_kernel = exp(-x.^2 / (2 * sigma^2));
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gauss_kernel = gauss_kernel / sum(gauss_kernel);
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% Circular convolution
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S_theta = conv([S_theta(end-half_width+1:end), S_theta, S_theta(1:half_width)], ...
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gauss_kernel, 'same');
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S_theta = S_theta(half_width+1:end-half_width);
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elseif exist('windowSize', 'var') && ~isempty(windowSize)
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% Moving average via convolution (circular)
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pad = floor(windowSize / 2);
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kernel = ones(1, windowSize) / windowSize;
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S_theta = conv([S_theta(end-pad+1:end), S_theta, S_theta(1:pad)], kernel, 'same');
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S_theta = S_theta(pad+1:end-pad);
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end
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end
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function contrast = computeRadialSpectralContrast(IMGFFT, r_min, r_max, threshold)
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% Apply threshold to isolate strong peaks
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IMGFFT(IMGFFT < threshold) = 0;
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% Prepare polar coordinates
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[ny, nx] = size(IMGFFT);
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[X, Y] = meshgrid(1:nx, 1:ny);
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cx = ceil(nx/2);
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cy = ceil(ny/2);
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R = sqrt((X - cx).^2 + (Y - cy).^2);
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% Ring region (annulus) mask
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ring_mask = (R >= r_min) & (R <= r_max);
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% Squared magnitude in the ring
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ring_power = abs(IMGFFT).^2 .* ring_mask;
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% Maximum power in the ring
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ring_max = max(ring_power(:));
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% Power at the DC component
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dc_power = abs(IMGFFT(cy, cx))^2;
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% Avoid division by zero
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if dc_power == 0
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contrast = Inf; % or NaN or 0, depending on how you want to handle this
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else
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contrast = ring_max / dc_power;
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end
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end
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function ret = getBkgOffsetFromCorners(img, x_fraction, y_fraction)
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% image must be a 2D numerical array
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[dim1, dim2] = size(img);
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s1 = img(1:round(dim1 * y_fraction), 1:round(dim2 * x_fraction));
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s2 = img(1:round(dim1 * y_fraction), round(dim2 - dim2 * x_fraction):dim2);
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s3 = img(round(dim1 - dim1 * y_fraction):dim1, 1:round(dim2 * x_fraction));
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s4 = img(round(dim1 - dim1 * y_fraction):dim1, round(dim2 - dim2 * x_fraction):dim2);
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ret = mean([mean(s1(:)), mean(s2(:)), mean(s3(:)), mean(s4(:))]);
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end
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function ret = subtractBackgroundOffset(img, fraction)
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% Remove the background from the image.
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% :param dataArray: The image
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% :type dataArray: xarray DataArray
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% :param x_fraction: The fraction of the pixels used in x axis
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% :type x_fraction: float
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% :param y_fraction: The fraction of the pixels used in y axis
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% :type y_fraction: float
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% :return: The image after removing background
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% :rtype: xarray DataArray
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x_fraction = fraction(1);
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y_fraction = fraction(2);
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offset = getBkgOffsetFromCorners(img, x_fraction, y_fraction);
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ret = img - offset;
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end
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function ret = cropODImage(img, center, span)
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% Crop the image according to the region of interest (ROI).
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% :param dataSet: The images
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% :type dataSet: xarray DataArray or DataSet
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% :param center: The center of region of interest (ROI)
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% :type center: tuple
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% :param span: The span of region of interest (ROI)
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% :type span: tuple
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% :return: The cropped images
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% :rtype: xarray DataArray or DataSet
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x_start = floor(center(1) - span(1) / 2);
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x_end = floor(center(1) + span(1) / 2);
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y_start = floor(center(2) - span(2) / 2);
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y_end = floor(center(2) + span(2) / 2);
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ret = img(y_start:y_end, x_start:x_end);
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end
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function imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
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%CALCULATEODIMAGE Calculates the optical density (OD) image for absorption imaging.
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%
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% imageOD = calculateODImage(imageAtom, imageBackground, imageDark, mode, exposureTime)
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%
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% Inputs:
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% imageAtom - Image with atoms
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% imageBackground - Image without atoms
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% imageDark - Image without light
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% 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 μm⁻¹ along each radial line
|
|
%
|
|
% Inputs:
|
|
% kx, ky - reciprocal space vectors (μm⁻¹)
|
|
% 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 μm⁻¹
|
|
|
|
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 μm⁻¹
|
|
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 |