I = imread('cameraman.tif');
I = im2double(I);
%圖像存儲類型轉(zhuǎn)換
T = dctmtx(8);
%離散余弦變換矩陣
B = blkproc(I,[8 8],'P1*x*P2',T,T');
mask = [1   1   1   1   0   0   0   0
       1   1   1   0   0   0   0   0
       1   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];
B2 = blkproc(B,[8 8],'P1.*x',mask);
I2 = blkproc(B2,[8 8],'P1*x*P2',T',T);
imshow(I)
title('原始圖像')
figure;
imshow(I2)
title('壓縮后的圖像')