A Pyramid-Based Watermarking Technique for Digital Color Images Copyright Protection

This paper proposes a pyramid-wavelet watermarking scheme for ownership verification of digital color images. The discrete wavelet transform (DWT) has been used extensively in recent years in watermarking systems. It provides the necessary perceptual invisibility and robustness. In this paper, a pre-DWT process is implemented using optimal pyramid transform (OPT), where one of the error images that are resulted from the pyramid transform is decomposed using DWT, and a watermark is inserted in one of its colors; red, green, or blue. Then, the watermarked color image is reconstructed. The filters used for OPT and DWT decomposition are randomly generated to increase the security of this algorithm. The simulation results show that the proposed algorithm achieves high average correlation against Gaussian and salt-and-paper noise.