# How to plot RGB intensity value from the specific pixel

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joynjo on 23 May 2017
Commented: joynjo on 23 May 2017
How to plot RGB intensity value from the specific pixel?. Let say I have 50 picked pixel coordinate, I would like to plot these values in to RGB graph.

Walter Roberson on 23 May 2017
Let R be a vector of the row coordinates of the selected pixels, and C be a vector of the corresponding column coordinates. Let your image be I. Then
reds = I(sub2idx(size(I), R(:), C(:), 1 * ones(length(R),1));
greens = I(sub2idx(size(I), R(:), C(:), 2 * ones(length(R),1));
blues = I(sub2idx(size(I), R(:), C(:), 3 * ones(length(R),1));
Now you could plot in whatever way seems appropriate. For example,
X = 1 : length(reds);
plot(X, reds, 'r', X, greens, 'g', X, blues, 'b');
joynjo on 23 May 2017
Thanks Walter

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