Digital Image Watermarking using Self Inverting Permutations - A Comparative Study

In this work we present a comparative study of two watermarking techniques, both based on frequency domain transformations but differing on watermark construction. Many state-of-the-art approaches utilize binary images as watermarks. An alternative way of watermark construction, which incorporates error correction properties, proposes the transformation of an integer number w into a self-inverting permutation (SiP). SiP can be represented in a two dimensional (2D) object, since images are 2D structures, and that constitutes a watermark. Through this study, we highlight the importance of developing robust digital image watermarking systems through their operation in real attack scenarios. Moreover, through the conduction of a series of experiments required for the comparative study, there are provided further insights regarding the strengths and weaknesses of each approach. Several image sizes have been tested along with a range of evaluation metrics for imperceptibility evaluation. In addition, robustness of both of the techniques has also been confirmed by applying a variety of attacks on the resulting images.