Multiple perceptual watermarks using multiple-based number conversion in wavelet domain

In this paper, a novel multiple watermarks coding and decoding system for image copyright protection is presented. Just noticeable difference (JND) threshold in the wavelet domain is used to exactly determine the locations for watermark embedding and dynamically control the watermark strength. A multiple-based number system is proposed to skillfully convert the watermarks information into values to be embedded in the choosing wavelet coefficients of the original image. We evaluated the capacity of the watermarking method in theory and analyse the possibility for inserting multiple watermarks. Experiments show our algorithm has excellent performance.