DCT压缩解压压缩比PSNR计算MATLAB源代码

DCT压缩解压压缩比PSNR计算MATLAB源代码clc; clear all; close all; I = imread('E:\wcp.jpg'); % 读取图片I=rgb2gray(I);

I = im2double(I) ;%图片存储类型转换

T = dctmtx(8);%离散余弦变换矩阵

B = blkproc(I,[8 8],'P1*x*P2',T,T');%对源图像进行DCT变换

mask = [1 1 1 0 0 0 0 0

1 1 1 0 0 0 0 0

1 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 0 0 0 0 0 0 0];

B2 = blkproc(B,[8 8],'P1.*x',mask);%数据压缩，丢弃右下角高频数据I2 = blkproc(B2,[8 8],'P1*x*P2',T',T);%进行反DCT变换

figure;

subplot(1, 2, 1); imshow(I, []);

subplot(1, 2, 2); imshow(I2, []);

imwrite(I, 'c:\\c1.png');

imwrite(I2, 'c:\\c2.png');

f1 = imfinfo('c:\\c1.png');

f2 = imfinfo('c:\\c2.png');

r = f2.FileSize/f1.FileSize;

[Row,Col]=size(I);

[Row,Col]=size(I2);

MSE=sum(sum((I-I2).^2))/(Row*Col); PSNR=10*log10(255^2/MSE)