Optimized Dithering for Quantization Index Modulation

Quantization index modulation (QIM) is a popular data hiding paradigm due to its considerable performance advantages over spread spectrum techniques. Nevertheless, the random dithering procedure in QIM suffers from the synchronization and distortion issues. From the perspective of lattices, this work shows that using fixed optimized dithering is beneficial for achieving a smaller amount of distortion to the cover object. This can be translated into better Peak Signal-to-Noise Ratio (PSNR) and Structural Similarity Index (SSIM) for the multimedia.