A blind watermarking algorithm based on singular value decomposition and quantization

A blind watermarking algorithm based on singular value decomposition and quantization in Contourlet domain is presented to protect the copyright of digital images. Firstly, a host image is decomposed by using Contourlet transform, and the low-frequency subband is divided into blocks. Then, by applying SVD to each block, the binary watermark information is embbeded by quantizing each singular value vector of each block. According to the quantization principle, blind extraction could be realized. Finally, the experimental results are given to show that, this algorithm can not only ensure the invisibility of the watermarked image, but also resist effectively various attacks, such as the filtering, adding noise, JPEG compression, cropping and so on.