A Watermark Algorithm Based on Space-domain and Transform-domain

An algorithm for watermark based on space-domain and transform-domain is described in the paper. Making use of the different characteristic of spatial domain and transform domain, the conflict between invisibility and robust in the algorithm for watermark can be prevented, and the density of embedded watermark can be increased. In the first stage of the proposed method, the unessential parts of the watermark are embedded to the host image by LSB algorithm in spatial domain. After that, the image is converted to frequency domain with wavelet packet transform and the significant parts of the watermark are embedded to the significant coefficients. With this scheme, more watermark data can be embedded to the host image and the watermark data won't be easily distorted. From the simulation results, we can see that the approach has good performance and robust to the crop and noise attack.