New watermark-removal method based on Eigen-image energy

• Published in: IET information security Vol. 5; no. 1; p. 43
• Main Authors: Hsu, T.-C., Hsieh, W.-S., Chiang, J.Y., Su, T.-S.
• Format: Journal Article
• Language: English
• Published: Stevenage The Institution of Engineering & Technology 01.03.2011
• Subjects: Computer information security; Energy distribution; Energy use; Noise levels; Noise reduction; Tradeoffs; Watermarking
• ISSN: 1751-8709; 1751-8717
• DOI: 10.1049/iet-ifs.2008.0055

Most watermark-removal methods treat watermarks as noise and apply denoising approaches to remove them. However, denoising methods remove not only this watermark energy, but also some of the energy of the original image. A trade-off, therefore, exists. To solve this problem, the relationships among the energies of the original image, the watermark and the watermarked image are initially determined using stochastic models. Then the energy of the watermark is estimated using just-noticeable-distortion (JND). Finally, the watermark energy is removed from the watermarked image using the energy distribution of its Eigen-images. The experimental results show that the proposed approach yields a mean peak signal-to-noise ratio (PSNR) of the predicted images that is 2.2 dB higher than that obtained using the adaptive Wiener filter, and a mean normalised correlation (NC) value of the extracted watermarks that is 0.27 lower than that obtained using the adaptive Wiener filter.