I = imread('cameraman.tif');
I = im2double(I);
%產(chǎn)生二維DCT變換矩陣
T = dctmtx(8);
%計算二維DCT
B = blkproc(I,[8 8],'P1*x*P2',T,T');
%二值掩模，用來壓縮DCT系數(shù)
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];
%只保留DCT變換的11個系數(shù)
B2 = blkproc(B,[8 8],'P1.*x',mask);
%DCT反變換，用來重構(gòu)圖像
I2 = blkproc(B2,[8 8],'P1*x*P2',T',T);
subplot(1,2,1)
imshow(I), 
subplot(1,2,2)
imshow(I2)