Distortion less watermarking of relational databases based on circular histogram modulation
The need for reversible or lossless watermarking methods has recently been highlighted to associate subliminal management information with losslessly processed media and to enable their authentication. This paper first analyzes the specificity and the application scope of lossless watermarking methods. It explains why early attempts to achieve reversibility are not satisfactory. They are restricted to well-chosen images, strictly lossless context and/or suffer from annoying visual artifacts. Circular interpretation of bijective transformations is proposed to implement a method that fulfills all quality and functionality requirements of lossless watermarking. Results of several bench tests demonstrate the validity of the approach.