HVS based Robust Image Watermarking Scheme using Slant Transform

This paper presents a robust algorithm for digital image watermarking based on Human Visual System (HVS). Watermark is embedded in the Slant Transform domain by altering the transform coefficients. The perceptibility of the watermarked image using proposed algorithm is improved over DCT based algorithm(9) by embedding the watermark image in selected positions based on the HVS weightage matrix. The proposed method is robust and the watermark image can survive to many image attacks like noise, bit plane removal, cropping, histogram equalization, rotation, and sharpening. Results are compared with DCT based watermarking method and found to be superior in terms of the quality of the watermarked image and resilience to attacks. The metrics used to test the robustness of the proposed algorithm are Peak Signal to Noise Ratio (PSNR) and Normalized Cross Correlation (NCC).