How can i detect Green and Blue color from an image?

My project is about colors and shapes detection. I detected what the shape is, But my problem is how to detect the color in this case? like this image for example.

[Rik]

This question is impossible to answer without an example and/or a description. Have a read here and here. It will greatly improve your chances of getting an answer.

[odai kiwan]

like this pic

Answer 1

[Cam Salzberger]

Hello Odai,

If you are able to determine the shape of objects in the image, then you likely have the location of the item as well - (row, col) of centroid, or maybe even dimensions or bounding box. If you are simply trying to answer an "is this object red or blue?", you could simply pick a pixel or a patch and check the greatest color channel:

if I(row, col, 1) > I(row, col, 2) && I(row, col, 1) > I(row, col, 3)
    disp('Red!')
elseif I(row, col, 2) > I(row, col, 3)
    disp('Green!')
else
    disp('Blue!')
end

Of course, that's pretty suboptimal and naive, but it serves to illustrate. You can do something smarter by doing the average over the whole shape, or compare the average's RGB vector to some known colors to find what it is "closest" to.

Hope that helps!

-Cam