Abstract:

In order to achieve the copyright protection of digital color images, a geometrically robust image spatial domain zerowatermarking algorithm is proposed. Firstly, the green layer of the color image’s geometrically invariant space is constructed by using the  image normalization method．Then, the significant region is obtained from the normalized image by utilizing the geometric center. Finally, the zerowatermarking is constructed by performing the XOR(Exclusive OR) operation on the pixel of the watermark with another pixel randomly extracted from the significant region. The theoretical analysis and experimental results show that the algorithm’s performance is more stable than the watermarking algorithm based on the significant region obtained from the normalized image by utilizing the invariant centroid. Compared with the same class zero watermarking algorithm based on digital wavelet transform (DWT), it has a stronger ability of antishearing, geometric distortions, image processing and signal processing attacks.

Key words: color image;image normalization;geometric attack;zerowatermarking