An Image Watermarking Technique Based on Classified Vector Quantization

摘要

Digital watermarking has been presented as a new method for copyright protection. It is a technique to insert imperceptible (and hard to remove) data into digital image, audio or video, so that it allows ownership to be established or a buyer to be identified. The common digital image watermarking techniques are spatial or transform-based, which are based on spread-spectrum communications. Most of transform-domain watermarking methods are based on Discrete Cosine Transforms (DCT) and robust to JPEG lossy compression. Recently, digital image watermarking based on another significant lossy compression technique, Vector Quantization (VQ), has been presented, which carries watermark information by codeword indices. It is quite effective, especially for the robustness to VQ compression with the same codebook. This paper presents a more favorable image watermarking method based on classified VQ. This technique can achieve excellent embedding performance and extract the watermark without the original image. Experimental results show that the proposed techniques are superior to some existing VQ-based watermarking algorithms, and the watermarked image is robust to some common signal processing operations.