HVS-Based Imperceptibility Evaluation for Steganography

The aim of steganography is to conceal the very existence of hidden communication, so imperceptibility is the primary demand. However there are short of corresponding evaluation methods. Most researchers still use Peak-Signal-to-Noise Ratio (PSNR) for their imperceptibility evaluation, while ignoring the speciality of steganography. In this paper, firstly, we present an objective method of imperceptibility evaluation for gray image, which is based on both characteristics of steganography and human visual systems (HVS).Then, based on the color masking, metric CHPSNR for color image is proposed. CHPSNR relates embedding capacity to steganography, and can reflect the localized distortion of stego images. Extensive experimental results demonstrate that our method is superior to global PSNR, which is consistent with HVS and can effectively evaluate the performance of steganographic algorithm.