Robust Algorithm of Digital Image Watermarking Based on Discrete Wavelet Transform

In this paper, a robust algorithm of digital image watermarking based on discrete wavelet transform is introduced. It adds binary image watermark into gray image and the host image is required for detecting. The algorithm have two characteristics: (1) It is adapted to various gray images owing to using the mean value of selected coefficients. (2) Arnold transform pretreatment eliminates spatial correlation and disperses the error bits among all pixels to make watermarking more strongly robust against cropping operation. Experiment results show that the proposed algorithm is invisible and robust against common image processing and cropping operation.