Semi-fragile Watermarking Algorithm Based on Image Character

Embedding watermark based on the attacks´ characteristic was brought up, and it brought forward the region division algorithm and the double steps embedding method, put forward the characteristic and its representation in DWT transform domain based on visual features model, and brought forward the quantized central limit theorem which was applied to adjusting the coefficients in general transform domain. These all made semi-fragile watermarking embedded through dynamic quantization achieve the greatest robustness. It gave DWT coefficient redressal algorithm and the best restore probability of the pixel value adjusting in experiments when the images were under attack. It led to a better invisibility of carrier image, a better robustness in the image processing, such as JPEG compression, noise adding, filtering, and a larger amount of embedded information. What´s more, it could ascertain the position of vicious attack exactly.