Robust image watermarking scheme by discrete wavelet transform

This paper proposes a robust digital image watermarking techniques by using discrete wavelet transform. The watermark is embedded in 2-level diagonal coefficient to achieve high performance in term of imperceptibility. The watermark is embedded by selecting a seed that generating pseudorandom noise sequence. Then the Watermark is extracted back by using the same pseudorandom noise sequence seed in the embedding. The experimental results show that the proposed algorithm provides good level of imperceptibility. Moreover, the watermarked image is robust against several attacks

An Improved Imperceptibility and Robustness of 4x4 DCT-SVD Image Watermarking with a Modified Entropy

A digital protection against unauthorized distribution of digital multimedia is highly on demand. Digital watermarking is a defence in multimedia protection for authorized ownership. This paper proposes an improved watermarking based on 4×4 DCT-SVD blocks using modified entropy in image watermarking. A modified entropy is used to select unnoticeable blocks. The proposed watermarking scheme utilizes the lowest entropy values to determine unnoticeable regions of the watermarked image. This paper investigates the relationship between U(2,1) and U(3,1) coefficients of the U matrix 4×4 DCT-SVD in image watermarking. The proposed watermarking scheme produces a great level of robustness and imperceptibility of the watermarked image against different attacks. The proposed scheme shows the improvement in terms of structural similarity index and normalized correlation of the watermarked image