DWT-based Imperceptibility Evaluation of Watermark in Watermarked Color Image
Hua Duan · 2008
The imperceptibility of the watermark is one of the most important aspects for the performance of the watermarking algorithm.Conventional measure of image quality PSNR can't evaluate the quality of the watermarked image well.The different background luminance,texture,frequency and the color of the image mask the human eyes differently.This characteristic can be used to improve the conventional measure PSNR.By calculating the masking threshold of the background luminance,the texture,frequency and the color of pixel,the masking-weight for each pixel was calculated and an imperceptibility measure with these weights was obtained for the watermark in the watermarked color image.The conventional measure and the new one were compared through different experiments.The result judged by the new measure is more close to the result judged by human eyes than the conventional measure.