Efficiency of discrete wavelet trasnform in digital watermarking

Digital watermarks have recently emerged as a possible solution for protecting the copyright of digital materials. The work presented in this thesis is concerned with the Discrete Wavelet Transform DWT based digital watermarking, and how the DWT is an efficient transform in the field of digital watermarking. Four efficiency test algorithms were proposed in this work, each uses a different level of DWT decomposition as an embedding domain for the binary pattern watermarks used, the four efficiency test algorithms were applied on both gray scale and colored images with RGB (green and blue channels were used only) and Ycbcr (Y luminance was used only) color spaces. Fifteen important watermark attacks were applied on the four algorithms. Results were studied and examined carefully, and that led to obtain an optimum algorithm which is based on multi-level embedding criteria. The optimum algorithm was tested against even harder attacks which were the dual attacks (more than one attacks at a time) and a Hard crop attack that removes almost 90% of the watermarked image data, then the performance of the optimum algorithm has been compared with some selected literature algorithms in the field.