Wavelet packets-based robust blind digital watermark scheme

A wavelet packets-based robust blind watermark scheme using chaotic encryption is proposed in this paper. Two chaotic sequences are modulated according characters of chaotic system, using for sub image extraction and watermark encryption. The binary watermark information is changed into one dimension sequence by module arithmetic. An encrypted watermark sequence can get after do XOR arithmetic with the sequence and a binary chaotic sequence after modulating. For embedding watermark, partition the original image into 8 times 8 blocks, extract sub image about one-fourth of total original image blocks by another chaotic sequence then wavelet packet decomposition is applied for it. Embed watermark by using relationships of wavelet packet coefficients. It realizes a blind extraction because extraction watermark doesnpsilat need original image. The experiment results show that proposed scheme is very robust against for various attacks such as JPEG compression, Gaussian noise, cropping and scaling, etc.