separate the red part of imge

I have an red flower image with green leaf. I want to separate only red flower. How can I do? Please help!

Answer 1

[Matthew Eicholtz]

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.

[PK]

May I know threshold value for colors. Please!

[Image Analyst]

The Color thresholder app, like I recommended, will tell you those.

Answer 2

[Image Analyst]

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