subplot(2,2,4); colormap(gray(256));image(W);title('从含水印图像中提取的水印'); imwrite(W,gray(256),'watermark.bmp','bmp');
subplot(2,2,4); colormap(gray(256));image(W);title('从含水印图像中提取的水印'); imwrite(W,gray(256),'watermark.bmp','bmp'); #Matlab http://hi.baidu.com/hainei_/item/1de7e039935d2ef897f88dfd