SVD图片有损压缩测试

注意文件名别保持成svd.m，这样与系统的默认svd程序冲突

图片处理函数生成的三组二维数组对应RGB，处理时保留一组

clear all;
close all;
clc;

a1=imread('C:\1.jpg');


[m n]=size(a1);
a1=double(a1);
a=a1(:,:,3); %图片有三个通道
imshow(mat2gray(a))
r=rank(a);
 [U S V]=svd(a);

%re=s*v*d';
re=U(:,:)*S(:,1:1)*V(:,1:1)';
figure;
imshow(mat2gray(re));
imwrite(mat2gray(re),'a.jpg')
%实际保存是S可以只保存20个字节,U,V按二维数组保存
re=U(:,1:20)*S(1:20,1:20)*V(:,1:20)';
figure;
imshow(mat2gray(re));
imwrite(mat2gray(re),'b.jpg')

re=U(:,1:80)*S(1:80,1:80)*V(:,1:80)';
figure;
imshow(mat2gray(re));
imwrite(mat2gray(re),'c.jpg')

re=U(:,1:150)*S(1:150,1:150)*V(:,1:150)';
figure;
imshow(mat2gray(re));
imwrite(mat2gray(re),'d.jpg')

re=U(:,1:250)*S(1:250,1:250)*V(:,1:250)';
figure;
imshow(mat2gray(re));
imwrite(mat2gray(re),'e.jpg')