Image watermarking in the wavelet domain

In the digital era of Internet, with multimedia products available freely on the web, copying and reproducing works of others has become extremely easy and the need appeared for copyright protection of digital data, much in the same way as for analog data. While encryption is a solution to protect the data transmitted from the seller to the buyer, watermarking has been proposed as a solution to ensure the copyright protection. Digital watermarking means embedding of information (i.e. a watermark) in media signals without making perceptible changes. There is a tradeoff among conflicting requirements: Imperceptibility, Robustness & security and Capacity. Common image watermarking techniques work in the spatial domain or frequency domain. We have proposed methods that operate in the DWT domain; the watermark is embedded using a perceptual mask based on the original image, thus making the watermark more secure and less visible to the human eye. This method was also extended to a new transform which is 4x expansive: the Hyperanalytic Wavelet Transform. We are currently working on using turbo codes for error correction of the watermark. Selected Publications: 1. Corina Nafornita, Alexandru Isar, Maria Kovaci, "Increasing Watermarking Robustness using Turbo Codes," IEEE International Symposium on Intelligent Signal Processing WISP 2009, Budapest, Hungary, 26-28 August 2009. [pdf] [presentation] Link: http://www.trivent.hu/WISP2009/ 2. Corina Nafornita, Alexandru Isar, "On the Choice of the Mother Wavelet for Perceptual Data Hiding," IEEE International Symposium on Signals, Circuits and Systems ISSCS 2009, Iasi, Romania, 9-10 July 2009, vol.1, pp. 233-236, ISBN 978-1-4244-3784-9. [pdf] [presentation] Link: http://scs.etc.tuiasi.ro/isscs2009/ 3. C. Nafornita, I. Firoiu, J.-M. Boucher, A. Isar, A New Watermarking Method Based on the Use of the Hyperanalytic Wavelet Transform Proc. SPIE Europe: Photonics Europe, vol. 7000: Optical and Digital Image Processing 70000W, pp.70000W-1-70000W-12, ISBN 97808194 71987, Strasbourg, April, 2008 Link: The original publication is available at: www.spie.org 4. C. Nafornita, A New Pixel-Wise Mask for Watermarking, Proc. of ACM Multimedia and Security Workshop 2007, Dallas, TX, USA. [pdf]