Vector Quantization Index Modulation watermarking using concentric hyperspherical codebooks

In this paper, a digital watermarking system based on vector quantization is presented. Each vector containing N samples is mapped on the surface of the hyperspheres each of which are associated with a message to embed the digital watermark. We called this method vector quantization index modulation (VQIM) since it is conventional QIM in the N-dimensional space. The performance of the method and its comparison to orthogonal code-based watermarking is investigated. Furthermore, we implemented the VQIM method on a real audio watermarking system and adopted it with the human auditory system. The experimental results show the robustness of this scheme against common attacks in audio watermarking such as MP3 compression, lowpass filtering, resampling etc.