Histogram modification and Bi-level moment preservation based reversible watermarking

Abstract

Reversible watermarking is technique to hide the secret information in an image and to reconstruct the original image after the extraction of the watermark. In this paper, we present a reversible watermarking algorithm based on block separation, moment preservation, histogram shifting and embedding secret information. The peak points of the blocks are identified and histogram shifting is performed to improve the embedding capacity of the image. Due to the increase in the embedding capacity of the proposed method, the distortion of the host image increases. The bi-level moment preservation technique is used, in order to improve the image quality. The performance of the proposed algorithm has been evaluated based on the parameters like embedding capacity, Peak Signal to Noise Ratio (PSNR) and Color Peak Signal to Noise Ratio (CPSNR) and compared with the existing histogram modification scheme and it is found to give better results.