The following references are also believed to represent the state of the art:
US Published Patent Application 2002/0087885 of Peled, et al.;
US Published Patent Application 2007/0220592 of Muehlbauer;
U.S. Pat. No. 4,907,080 to Campbell, at al.;
U.S. Pat. No. 5,870754 to Dimitrova, et al.;
U.S. Pat. No. 6,466,670 to Tsuria, et al.;
U.S. Pat. No. 6,633,651 to Hirzalla, et al.;
U.S. Pat. No. 6,961,467 to Sirivara, et al.;
U.S. Pat. No. 6,968,337 to Wold;
PCT Published Patent Application WO2005/043359 of Macrovision
Corporation;
PCT Published Patent Publication WO2008/059393 of NDS Limited;
PCT Published Patent Publication WO2008/096281 of NDS Limited;
UK Published Patent Application GB2369203 of Assertion Limited;
Paper entitled “Efficient video similarity measurements with video signature” by Sen-ching S. Cheung and Avideh Zakhor, University of California, Berkeley;
Paper entitled “Video similarity detection with video signature clustering” by Sen-ching S. Cheung and Avideh Zakhor, University of California, Berkeley;
Paper entitled “Fast similarity search and clustering of video sequences on the world-wide web” by Sen-ching S. Cheung, Center of Applied Scientific Computing Lawrence Livermore National Laboratory and Avideh Zakhor, University of California, Berkeley;
Paper entitled “Robust video signature based on ordinal measure” by Xian-Sheng Hua, Xian Chen and Hong-Jiang Zhang, Microsoft Research, Asia;
Paper entitled “Fast video matching with signature alignment” by Timothy C. Hoad and Justin Zobel, RMIT University, Melbourne, Australia;
Paper entitled “A scalable signature scheme for video authentication” by Pradeep Atrey, Wei-Qi Yan, Mohan S. Kankanhalli, National University of Singapore;
Press Release Mar. 13, 2006 of Motion DSP for Ikena Copyright;
Paper entitled “Call for proposals on image & video signature tools” by International Organisation for Standardization, ISO/IEC JTC1/SC29/WG11, Coding Of Moving Pictures And Audio, MPEG Video Sub-Group, July 2007;
Paper entitled “A robust content based digital signature for image authentication” by Marc Schneider and Shih-Fu Chang, Columbia University; and
Extracts from the website of IDDE Inc for Image monitoring service.