A Zero-watermark Method Based on Texture Characteristic of Image Blocks for Stereo Images

A zero-watermark method based on the texture characteristic of image block for stereo images is proposed. Different blocks have own textures, and the images can be classified into two types according to the block energies, including smooth and non-smooth. The block energy is calculated by summing of alternative current coefficients. The block type relationships between blocks are employed for constituting the zero-watermark information. The zero-watermark is embedded into images without any modification, and solves the contradiction between transparency and robustness of the watermarking. Experimental results show the transparency and robustness against attacks such as noise, JPEG compression, Gaussian filtering, median and average filtering, and crops.