A hybrid scheme for robust color image watermarking using DSWT in DCT domain

Abstract

This paper proposes a hybrid robust image watermarking scheme based on three levels of Discrete Stationary Wavelet Transform (DSWT) in the Discrete Cosine Transform (DCT) domain. The host image colors (red, green and blue) are separated, and then the DCT is applied on each color after separation. The DSWT is utilized to divide the DCT output into four sub-bands (3 levels). These sub-bands are (A, H, V, D) matrices with the same image size. The watermark is embedded on matrix A. The results of the proposed watermarking scheme are compared with other state-of-the-art schemes. The comparison is based on visualization to detect any degradation of the watermarked image, Peak Signal-to-Noise Ratio (PSNR) of the watermarked image, Normal Correlation (NC) of the extracted watermark after detection, applying attacks, and then calculating the PSNR and NC.