Robust adaptive image watermarking using visual models in DWT and DCT domain

In this study, two image adaptive invisible digital watermarking algorithms based on DWT and DCT are proposed for copyright protection. The first proposed algorithm utilizes Watson's visual model (JND) to determine the watermarking strength necessary to invisibly embed the watermark in the DCT block coefficients of the cover image by controlling the power of strength of JND. The second proposed technique embeds the watermark by modifying coefficients of the vertical and the horizontal detail sub-bands of wavelet sub-blocks, chosen with a secret key. The visual model is designed to generate a Just Noticeable Difference mask (JND) by analyzing image characteristics such as textures and luminance of the cover image in the DWT based domain. Since, the secret key is required for both embedding and extraction of watermark, it is not possible for an unauthorized user to extract the embedded watermark. The proposed schemes are robust to common image processing distortions like filtering, JPEG compression and noise. Experimental results show that the proposed schemes are efficient, imperceptible and the quality of watermarked image is very well and robust for various image processing distortions. © 2010 Asian Network for Scientific Information.