How to extract colorbar value of all pixels in figure?

Question

Noah 2017-5-24

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/341791-how-to-extract-colorbar-value-of-all-pixels-in-figure

评论： Prasanth Thangavel 2019-9-5

question.pdf

For example, if the following documentation code is used...

figure(1)
N = 1024;
n = 0:N-1;
w0 = 2*pi/5;
x = sin(w0*n)+10*sin(2*w0*n);
s = spectrogram(x);
spectrogram(x,'yaxis')

The spectogram attached is produced, and when the data cursor is used, the value "index" gives the pixels value on the colorbar. How can I extract this value for all pixels in the figure?

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Answer 1

J Philps 2017-5-30

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https://ww2.mathworks.cn/matlabcentral/answers/341791-how-to-extract-colorbar-value-of-all-pixels-in-figure#answer_268976

The color data can be accessed through the CData of the Image. I have modified your sample code to populate the variable 'spectData' with the corresponding 'Index' information that you were accessing through the data cursor:

figure(1); N = 1024; n = 0:N-1; w0 = 2*pi/5; x = sin(w0*n)+10*sin(2*w0*n); s = spectrogram(x); spectrogram(x,'yaxis')

ax = gca; spectData = ax.Children.CData;

The resulting spectData will be a 129x7 double.