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; %figure(3);imagesc(xgray);colormap(gray) xb=xgray(381:388,181:188); %figure(4);imagesc(xb);colormap(gray) %p=1 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 %p=2 xd=double(xb); xc=xd-128; y=dct(dct(xc')'); %since y=dct(dct(x')')=> y=c*xc*c'; p=2; q=p*8./hilb(8); yq=round(y./q); yq %p=4 xd=double(xb); xc=xd-128; y=dct(dct(xc')'); %since y=dct(dct(x')')=> y=c*xc*c'; p=4; q=p*8./hilb(8); yq=round(y./q); yq %p=10 xd=double(xb); xc=xd-128; y=dct(dct(xc')'); %since y=dct(dct(x')')=> y=c*xc*c'; p=10; q=p*8./hilb(8); yq=round(y./q); yq
yq =
13 9 1 0 1 0 0 0
37 -4 -1 -1 0 0 0 0
-4 -6 -1 2 0 0 1 0
-2 4 2 1 -1 0 0 -1
0 1 -1 -2 0 1 0 0
0 -1 0 0 1 0 0 1
1 0 1 1 0 -1 0 0
-1 0 -1 0 -1 1 0 -1
yq =
7 5 1 0 0 0 0 0
18 -2 -1 -1 0 0 0 0
-2 -3 -1 1 0 0 0 0
-1 2 1 0 0 0 0 0
0 1 -1 -1 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
yq =
3 2 0 0 0 0 0 0
9 -1 0 0 0 0 0 0
-1 -1 0 0 0 0 0 0
-1 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
yq =
1 1 0 0 0 0 0 0
4 0 0 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