Analysis of Different Interpolation Methods in Watermarking Scheme Based on Prediction Error Expansion, Interpolation and Segmentation

Watermarking is a way to keep secret information hidden in the cover media that is indistinguishable to the human eye but easily noticeable to the decoder. In this paper, a watermarking scheme is analyzed based on prediction error expansion using interpolation and segmentation in order to find an optimal watermarking technique. In this method, watermark is embedded into a cover image using additive prediction error expansion method by interpolating and segmenting the cover image. Interpolation reduces artifacts and segmentation distinguishes sharp areas and smooth areas. Here, interpolation is used instead of other prediction method in order to reduce the computation time and complexity of the method. Segmentation is used so that higher embedding capacity can be used for sharp segments and lower embedding capacity for smooth regions using additive PEE. The interpolation method will be varied to determine the most efficient interpolation method for this scheme. Different noise attacks will be applied to find the robustness of the method. The idea of applying different bits in different segments will be applied. For this purpose, the segments are classified into different classes according to their average slopes. The segments that have higher slopes will get more bits embedded into them. Finally, different performance parameters like PSNR, NCC, MSE & embedding capacity will be calculated for evaluating the proposed scheme.