getting RGB from image created with imagesc

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Hi. I am creating am image of a matrix using imagesc.
i want to get the RGB values of every pixel in the image.
I tried using get(im,'CData'), but it gives back the matrix that created the image.
how can do it?
thanks, Ariel

Accepted Answer

Mike Garrity
Mike Garrity on 15 Mar 2016
Edited: Mike Garrity on 15 Mar 2016
You probably want ind2rgb. But if you're using imagesc, rather than image, you're probably need to scale your color values. It looks something like this:
v = ??; % my matrix
map = colormap;
minv = min(v(:));
maxv = max(v(:));
ncol = size(map,1);
s = round(1+(ncol-1)*(v-minv)/(maxv-minv));
rgb_image = ind2rgb(s,map);
If you have integer color values, then you don't need to do that scaling before calling ind2rgb.
  1 Comment
ariel on 16 Mar 2016
Edited: ariel on 16 Mar 2016
thanks. However, when I get the RGB data, it is slightly different than what appears on the screen when I use the cursor.
The data is:
0.1250 1.0000 0.8750
while the screen shows this:
Another thing is mapping doubles to RGB - the help of ind2rgb clearly states that this is possible, however when I omitted the rounding of 's' in your example, I got the following error:
Subscript indices must either be real positive integers or logicals.
Error in ind2rgb (line 26)
r = zeros(size(a)); r(:) = cm(a,1);
I'm using Matlab 2015b

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More Answers (1)

Image Analyst
Image Analyst on 15 Mar 2016
imagesc() does not create images - it displays them. So you already have the image. If you want it pseudocolored, look up colormap in the help - there are a variety of predefined colormaps to choose from: hot, winter, jet, parula, etc. Pick one that you like and use ind2rgb to create a pseudocolored RGB image from your gray scale image.
% Use hsv color map to create an RGB image from a gray scale image:
rgbImage = ind2gray(grayImage, hsv(256));
Image Analyst
Image Analyst on 16 Mar 2016
Yes. If you want some certain amount, specify it. Like if you want 1000 colors, say jet(1000).

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