Wavelet tree based watermarking algorithms are generally using the wavelet coefficient energy difference for copyright protection and ownership verification. Since there are cryptanalysis-based methods addressed for successfully attacking wavelet tree based watermarking algorithm of wavelet tree quantization (WTQ), it is the motivation in this research to devise a scheme to improve WTQ's robustness. Furthermore, the combination of wavelet tree based watermarking techniques, chaotic system for block based scrambling techniques have not been seen or few discussed in the literatures. The study in this paper has presented such research findings and contribution for the academic and industry fields. Therefore, a chaotic system is adopted for WTQ to counteract the attacks in this paper. The digital image is first split into many blocks and the chaotic system is applied to scramble the image before the implementation of WTQ. The experimental results demonstrate the effectiveness of using chaotic system to enhance the security of WTQ, especially, to resist cryptanalysis attack. In addition, such mechanism also works for other advanced wavelet tree based algorithms like wavelet tree group modulation (WTGM) and dynamic energy enabled differentiation (called DEED) watermarking techniques.
- Chaotic system
- Wavelet-tree quantization