Abstract: Reversible watermarking has fetched enormous attention of researchers in its domain in past decade as the need of recovering the original work image after extracting the watermark. There are many researches in this field are done and various techniques are available. So to choose which one is the best technique, a definite need arises to compare those techniques on some parameter like PSNR and others. This paper presents a comparative study of three basic robust techniques, which are Least Significant Bit (LSB), Difference Expansion (DE) and Reversible Contrast Mapping (RCM) technique. This work has been implemented through MATLAB.

Keywords: Reversible Watermarking, Difference Expansion (DE), Least Significant Bit (LSB), Reversible Contrast Mapping (RCM), PSNR (Peak Signal to Noise ratio), Processing Time.