x=imread('mj.jpg'); x=double(x); r=x(:,:,1);g=x(:,:,2);b=x(:,:,3); xgray=0.2126*r+0.7152*g+0.0722*b; %imagesc(xgray);colormap(gray) xb=xgray(81:88,81:88); %imagesc(xb) xd=double(xb); xc=xd-128; y=dct(dct(xc')'); %since y=dct(dct(x')')=> y=c*xc*c'; p=1; q=p*8./hilb(8); yq=round(y./q); yq xd=double(xb); xc=xd-128; y=dct(dct(xc')'); %since y=dct(dct(x')')=> y=c*xc*c'; p=20; q=p*8./hilb(8); yq=round(y./q); yq
yq =
-115 -1 0 0 0 0 0 0
1 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
yq =
-6 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0