Help me generate better spectrogram data using Matlab?

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Catherine
Catherine 2024-7-17
编辑： Divyanshu 2024-8-7
Hi everyone
I am trying to generate spectrograms for .mat EEG files to show the breakdown of frequencies over time. I have got a series of spectrograms that look like this but I am not sure how to alter the code so they are more useful. My code currently is this:
% Set the directory containing .mat files
dataDir = 'C:\Users\clloy\Downloads\spectrogram_data_to_use';
% Get a list of all .mat files in the directory
matFiles = dir(fullfile(dataDir, '*.mat'));
% Electrode information (modify as per your electrode configuration)
electrodes = 1:32; % Assuming electrodes are labeled from 1 to 32
% Loop through each file and generate spectrograms for each electrode
for k = 1:length(matFiles)
% Load the .mat file
matFilePath = fullfile(dataDir, matFiles(k).name);
dataStruct = load(matFilePath);
% Extract the Clean_data variable
if isfield(dataStruct, 'Clean_data')
Clean_data = dataStruct.Clean_data;
% Sampling frequency (Hz)
fs = 128; % Sampling rate is 128 Hz
% Size of Clean_data
[numElectrodes, numSamples] = size(Clean_data);
% Loop through each electrode and generate spectrogram
for elecIdx = 1:numElectrodes
% Get data for current electrode
electrodeData = Clean_data(elecIdx, :);
% Generate spectrogram
figure;
spectrogram(electrodeData, 256, [], [], fs, 'yaxis');
% Add title and labels
title(['Spectrogram of Electrode ', num2str(elecIdx), ' - File: ', matFiles(k).name]);
xlabel('Time (s)');
ylabel('Frequency (Hz)');
% Customize y-axis labels for electrodes
ax = gca;
ax.YTickLabel = compose('%.1f', ax.YTick);
% Save the figure as an image file
saveas(gcf, fullfile(dataDir, [matFiles(k).name, '_electrode_', num2str(elecIdx), '_spectrogram.png']));
% Close the figure to avoid excessive memory usage
close(gcf);
end
else
warning('File %s does not contain the variable "Clean_data". Skipping...', matFiles(k).name);
continue;
end
end
Please let me know if theres anything I can do to alter it and make the spectrograms better!

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回答（1 个）

Divyanshu
Divyanshu 2024-8-7
编辑：Divyanshu 2024-8-7
Hi @Catherine,
In order to make the spectrograms better, you can make use of certain options of 'spectrogram()' function like 'windowSize','noverlap'.
You can read more about these options in the following documentation link:
https://www.mathworks.com/help/releases/R2023b/signal/ref/spectrogram.html#d126e200473
Hope it helps!

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