i am working on recognition of signboards .I removed background. Now i want to crop only the signboard within redcircle ..pls help me with code

I used below code to separate background from signboard

I = imread('prj.jpg'); pic=I(1:size(I,1)/2,1:size(I,2)/2,:);

for mm = 1:size(pic,1) for nn = 1:size(pic,2) if pic(mm,nn,1) < 80 pic(mm,nn,2) > 80 pic(mm,nn,3) > 100 gsc = 0.3*pic(mm,nn,1) + 0.59*pic(mm,nn,2) + 0.11*pic(mm,nn,3); pic(mm,nn,:) = [gsc gsc gsc]; end end end imshow(pic)

Now want to crop only the signboard for feature extraction .pls provide code