说明：  用matlab实现的基于LSB的数字水印算法。算法可以在BMP灰度图像中嵌入水印，水印信息为二值图像，并将其扩展到与原始图像同样大小，进行重复嵌入，提高鲁棒性。同时算法中给出了PSNR值以评价水印图像的效果，
(Using matlab realize the number of LSB-based watermarking algorithm. Algorithm can be embedded BMP gray image watermark, watermark information for the binary image, and its expansion to the original image the same size, the repetition of embedding, improve robustness. At the same time algorithm PSNR values are given to evaluate the effect of watermark images,)