Improving Spread Spectrum Based Image Watermarking Through Non-binary Channel Coding

In this paper, we investigated on how to combine M-ary modulation with shortened Reed-Solomon (RS) codes, in the context of spatial spread spectrum based watermarking schemes. Analytical expressions and bounds for the bit error rate are derived and compared with empirical results for several types of images. It is shown that, for low output error rates, there exists an improvement in performance using both concepts simultaneously. It will be also demonstrated that, in general, the resulting efficiency in watermarking detection outperforms binary BCH codes used in conjunction with binary signaling. The effectiveness of concatenating M-ary modulation with RS codes is also assessed under JPEG compression for still images and MPEG-2 compression for video sequences.