A Novel Watermarking Scheme in Contourlet Domain Based on Schur Factorization

A novel blind digital image watermarking scheme based on Schur factorization in contourlet domain is proposed in this paper. Firstly, the original cover image is decomposed by contourlet domain, then Schur factorization is adopted to the selected symmetric blocks determined by the lowpass subband where watermark information is embedded. Additionally, the watermark image is encrypted by a pseudorandom sequence generated by the piecewise linear map before embedded. Experimental results show that in comparison with similar schemes based on singular value decomposition, the proposed method is more invisible and robust against most common image processing attacks, such as median filter, noise addition, cropping, JPEG compression, and so on.