I=imread('cameraman.tif');           % MATLAB自帶的圖像，如圖3-3所示
imshow(I);
clear;close all 
I=imread('cameraman.tif');
imshow(I);
I=im2double(I);
T=dctmtx(8);
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);    % 此處為點(diǎn)乘(.*)
I2=blkproc(B2,[8 8], 'P1*x*P2',T',T);
figure,imshow(I2);                 % 重建后的圖像如圖3-4所示