Robust Wavelet-Based Watermarking Using Dynamic Strength Factor
This work addresses ownership protection for digital images in unsecured networks, offering an incremental improvement over existing watermarking techniques.
The paper tackles the trade-off between imperceptibility and robustness in digital image watermarking by proposing a wavelet-based method with an adaptive strength factor, achieving improved PSNR and BER results compared to recent methods under attacks like Median Filter, Gaussian Filter, and JPEG compression.
In unsecured network environments, ownership protection of digital contents, such as images, is becoming a growing concern. Different watermarking methods have been proposed to address the copyright protection of digital materials. Watermarking methods are challenged with conflicting parameters of imperceptibility and robustness. While embedding a watermark with a high strength factor increases robustness, it also decreases imperceptibility of the watermark. Thus embedding in visually less sensitive regions, i.e., complex image blocks could satisfy both requirements. This paper presents a new wavelet-based watermarking technique using an adaptive strength factor to tradeoff between watermark transparency and robustness. We measure variations of each image block to adaptively set a strength-factor for embedding the watermark in that block. On the other hand, the decoder uses the selected coefficients to safely extract the watermark through a voting algorithm. The proposed method shows better results in terms of PSNR and BER in comparison to recent methods for attacks, such as Median Filter, Gaussian Filter, and JPEG compression.