how to extract each region separately ?

Hello ;

I have used a meanshift method to segment RGB image. I have obtained a first matrix called « value » including a result of segmented image. I also obtained a second matrix called « label » which includes the labels corresponding of each segmented region. Could you please show me how can I extract the corresponding pixels (from a matrix “value”)of each labelled region (from a matrix “label”) in order to apply Zernike moment on each segmented region. Many thanks in advance.