Robust copyright protection scheme based on discrete cosine transform and secret sharing techniques

This paper presents a robust copyright protection scheme based on discrete cosine transform (DCT) and secret sharing techniques. The scheme cannot only use a binary image of arbitrary size as the watermark, but also generate shares without the need of a codebook. The scheme first performs the DCT on a host image to obtain the image features and uses these features to generate a master share. The master share and a binary watermark are then used to generate an ownership share, according to the secret sharing technique. The hidden watermark, used for copyright verification, can be revealed by combining the master share with the ownership share. It is shown that the hidden watermark can be effectively revealed by the proposed scheme, even if the visual quality of protected images has been greatly degraded. Moreover, the proposed scheme achieves superior resistance to several image processing operations, compared with existing schemes. (C) 2008 SPIE and IS&T.