How can I eliminate the pixels on an image that contain more blue or red than green?

I am working on a project with plants and I would like the program to detect the green objects .

Answer 1

[Joseph Cheng]

create a mask using a threshold.

samp(:,:,1) = repmat(0:.1:1,11,1);
samp(:,:,3) = repmat([0:.1:1]',1,11);
samp(:,:,2) = .5*ones(size(samp(:,:,1)));
subplot(1,2,1),image(samp)
mask = repmat(samp(:,:,1)<samp(:,:,2) & samp(:,:,3)<samp(:,:,2),1,1,3);
greenIM = zeros(size(samp));
greenIM(mask) = samp(mask);
subplot(1,2,2),imagesc(greenIM)