Digital watermarking was introduced during the last decade as a complementary technology to protect digital multimedia data. Watermarking digital video material has already been studied, but it is still usually regarded as watermarking a sequence of still images. However, it is well-known that such straightforward frame-by-frame approaches result in low performance in terms of security. In particular, basic intra-video collusion attacks can easily defeat basic embedding strategies. In this paper, an extension of the simple temporal frame averaging attack will be presented, which basically considers frame registration to enlarge the averaging temporal window size. With this attack in mind, video processing, especially video mosaicing, will be considered to produce a temporally coherent watermark. In other words, an embedding strategy will be proposed which ensures that all the projections of a given 3D point in a movie set carry the same watermark sample along a video scene. Finally, there will be a discussion regarding the impact of this novel embedding strategy on di?erent relevant parameters in digital watermarking e.g. capacity, visibility, robustness and security.
This paper is published in EI 2004, lectronic imaging 2004, Security, Steganography, and Watermarking of Multimedia Contents, 18-22 January 2004, San Jose, USA, Proceedings of SPIE Volume 5306 and is made available as an electronic preprint with permission of SPIE. One print or electronic copy may be made for personal use only. Systematic or multiple reproduction, distribution to multiple locations via electronic or other means, duplication of any material in this paper for a fee or for commercial purposes, or modification of the content of the paper are prohibited.