how can i read im2c more clearly, there are some questions...

[TrackingBird]

RR=im(:,:,1);GG=im(:,:,2);BB=im(:,:,3); index_im = 1+floor(RR(:)/8)+32_floor(GG(:)/8)+32_32*floor(BB(:)/8);

can you explain the index_im, or can you use chinese ,,,thanks