Digital watermark is invisible mark embedded in digital image

video or audio documents

which can be detected to protect copyright of multimedia data. The thesis describes a watermarking scheme based on CL multi-wavelets. After the CL multi-wavelet transformation of an image

most energy of the image is mainly concentrated on its lowest resolution sub-image. Moreover

most energy of the lowest resolution sub-image is further concentrated on its first component. Because lowest resolution sub-image can survive from some transformation such as compression

this scheme can improve robust of embedded watermark. But the invisibility of watermark is reduced at that time because of the sensitivity of the lowest resolution sub-image to HVS(Human Visual Model). The position to embed watermark is selected with a trade-off between robustness and invisibility. And preprocessing of the watermark image is here for declining the difference between the watermarked and original image. To deal with attack of counterfeit

it uses not additive method but replacement algorithm when embedding watermark. The correlation between the original and extracted watermark is computed to tell whether there exists watermark in the image. The performance of the proposed watermarking is invisible to HVS and robust to a variety of signal distortions

such as JPEG compression

filtering

cropping and incorporating attacks.