separate the red part of imge

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PK
PK on 6 Oct 2016
Commented: Image Analyst on 6 Oct 2016
I have an red flower image with green leaf. I want to separate only red flower. How can I do? Please help!

Accepted Answer

Matthew Eicholtz
Matthew Eicholtz on 6 Oct 2016
Edited: Matthew Eicholtz on 6 Oct 2016
A naive approach would be to extract "red" colors from the image:
I = imread('peppers.png');
R = I(:,:,1);
G = I(:,:,2);
B = I(:,:,3);
% Here I am naively defining "red" as the red layer being greater than
% some threshold and the blue and green layers being less than that threshold
thold = 100;
mask = R>thold & G<thold & B<thold;
R(~mask) = 255;
G(~mask) = 255;
B(~mask) = 255;
J = cat(3,R,G,B);
figure; montage(cat(4,I,J),'Size',[1 2]);
More advanced approaches exists (google "image segmentation"). For instance, see the MATLAB example for color-based segmentation using k-means clustering.
  2 Comments
Image Analyst
Image Analyst on 6 Oct 2016
The Color thresholder app, like I recommended, will tell you those.

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More Answers (1)

Image Analyst
Image Analyst on 6 Oct 2016
Use the Color Thresholder on the Apps tab of the toolbar ribbon.
Or else see my File Exchange for several color segmentation demos. http://www.mathworks.com/matlabcentral/fileexchange/?term=authorid%3A31862

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