Reversible secret image sharing scheme with enhanced stego image visual quality

Secret Image Sharing is a technique to share a secret image among n participants using Shamir´s secret sharing scheme. Secret image is revealed if any k of the n shares is processed according to the scheme. Research reported in the literature is focused on improving known issues of the method. Reconstruction without distortion, reducing the size expansion of the share images, improving stego image quality and enhancing authentication ability of the method are some of the issues. Recovering cover images after the revealing procedure is an important issue. In 2009, Wu et al. proposed a technique based on Reversible Steganography to solve this problem. A location map is used to recover cover images, which needs extra information. The proposed method outlined in this paper does not need any information except shares to recover cover images. In addition, visual quality of the shares or the Peak Signal to Noise Ratio (PSNR) values of stego images are improved which is used to demonstrate the effectiveness of the method. Experimental results indicate a 3 dB PSNR improvement on the average compared to Wu et al.´s method.