Image Dual Watermark Algorithm Based on Lifting Wavelet and Liu Chaotic System

A novel multipurpose image dual watermarking algorithm is proposed. Utilize the sequences X and Y generated by 3-D Liu chaotic system to control selecting embedding coefficient of visible watermark, and the visible watermark is embedded in the image spatial domain to achieve the goal of copyright notification. By utilizing the chaotic sequences Y and Z, some image blocks that were not embedded visible watermarks are selected randomly. By using coefficients quantization technique, the robust watermark that can be blindly extracted is embedded in the lifting wavelet transform (LWT) domain of those selected bocks to obtain the aim of copyright protection. Simulation results show that the visible watermark can be removed entirely by legal users but is hard to remove by illegal users, the impact of the invisible watermark on the image quality is slight, and the invisible watermark is robust to common image processing operations.