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