Dual digital watermarking algorithm for copyright protection and tamper authentication
一种兼具版权保护及窜改认证双重功能的数字水印算法

This paper presented a new dual digital image watermarking. Firstly embedded copyright watermark according to comparing the relationship of center and adjacented coefficients in the DWT middle-frequency coefficients of original image, then adaptively embedded the semi-fragile watermark into intermediate frequency domain of the original image. Both of watermarks could be detected and extracted from the watermarked image without the original image. Experimental results show that the method has good invisibility, copyright watermark is robust against normal image processing and kinds of attacks, for example JPEG compression, cutting, adding noise, authentication watermark can detect the location of any minute changes in images, and can be widely used in practice.