Joint ownership verification for digital images

Many image watermarking schemes for copyright protection have been proposed in recent years, but they seldom deal with the problem of joint ownership verification if an image is created collaboratively. This paper addresses this problem by applying a secret sharing scheme to the watermarking scheme so that the secret key, which determines the embedded watermark, is shared among the multiple owners and only a authorized number of owners can verify the ownership. Experimental results show that this scheme is robust against a wide range of common signal processing procedures such as compression, median filtering and additive noise.