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;
xb=xgray(81:88,81:88);
xd=double(xb);
xc=xd-128;
y=dct(dct(xc')');
p=1;
q=p*8./hilb(8);
yq=round(y./q);
yq
xd=double(xb);
xc=xd-128;
y=dct(dct(xc')');
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