先贴代码，有空再补

clear;clc;img = imread('test.jpg');img_gray = rgb2gray(img);img_gray = imresize(img_gray,0.5);[m,n] = size(img_gray);[u,s,v] = svd(double(img_gray));r = 2;    % 压缩率K =round(2 * m * n / ( r * (m + n + 1)));if K > min(m,n)    K = min(m,n);endimg_c = zeros(size(img_gray));for i = 1:K    img_c = img_c + s(i,i) * u(:,i) * v(:,i)';end%subplot(2,2,1); imshow(img,[]); title('origin');%subplot(2,2,2); imshow(img_gray,[]); title('gray');subplot(2,2,3); imshow(img_c,[]); title(['zip r = ',num2str(r), ' zip Image']);imwrite(img_c,'zip.bmp')