Conversion of (129x7 complex double) to an Image

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I have a variable s (129x7 complex double). I want to save it as an image. I have tried many ways but I can't save it.
for k=1:size(cm,2)
s = spectrogram(cm(:,k));
save(['Spectro_Subj' num2str(h) '_channel' num2str(i) '_window' num2str(k) '.mat'],'s')
Walter Roberson
Walter Roberson on 4 Feb 2023
Tiff supports ComplexIEEEFP. However MATLAB's interface to libTiff does not support that.

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Accepted Answer

Image Analyst
Image Analyst on 6 Feb 2023
Edited: Image Analyst on 7 Feb 2023
for k=1:size(cm,2)
baseFileName = sprintf('Spectro_Subject %d_channel %d_window %d.png', h, i, k);
fullFileName = fullfile(pwd, baseFileName);
fprintf('For k = %d, saving "%s".\n', k, fullFileName);
exportgraphics(gca, fullFileName);
DGM on 7 Feb 2023
Note the only reason why I don't use exportgraphics() isn't because saveas() is better. I just run an older version, so I can't verify my example with something I can't run.

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More Answers (2)

Walter Roberson
Walter Roberson on 4 Feb 2023
you could use the tiff gateway and write the imaginary component as unassociated alpha. There is an example at
The difference is that you would specify 2 samples per pixel instead of 4, and you would use IEEEFP sample format.
There is a file exchange contribution for writing floating-point tiff that is worth studying.
So... you would be able to use an image file, and use floating point samples, and write two channels.
What you should not expect is for any other program to be able to produce a readable image from the data

DGM on 4 Feb 2023
Moved: Image Analyst on 6 Feb 2023
Are you sure you don't want to just save a graphical representation (i.e. a plot)?
% some fake test signal
fs = 1000;
t = 0:1/fs:2-1/fs;
y = chirp(t,100,1,200,'quadratic');
% plot the spectrogram
% save the figure
If so, there are many different ways it can be represented.
  1 Comment
Muhammad on 6 Feb 2023
Moved: Image Analyst on 6 Feb 2023
thanks alot that is what i was looking for.

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