A visual saliency modulated just noticeable distortion profile for image watermarking

Previous perceptual watermarking schemes only partially used the results from human visual system (HVS) studies. The perceptual adjustment of the watermark is mainly based on different visual sensitivity models. Numerically, visual sensitivity can be regarded as the inverse of the just noticeable distortion (JND). Another aspect affecting human perception towards visual signal is visual attention which can enhance or reduce the actual visual sensitivity and consequently the JND profile needs to be adjusted. The technique described in this paper assists image watermarking by producing a visual saliency modulated JND profile that can be used as a guide to optimize image watermarking. Experimental results with subjective test confirm the improved performance of our visual saliency modulated JND profile for image watermarking. Our saliency modulated JND profile is capable of shaping lower injected-watermark energy onto more sensitive regions and higher energy onto the less perceptually significant regions in the image, which yields better visual quality of the watermarked image.