[1] [1] A. Blake, M. Isard, and D. Reynard, Artificial Intelligence 78, 101 (1995).

[2] [2] M. Isard and A. Blake, in Proceedings of the European Conference on Computer Vision 1, 343 (1996).

[3] [3] D. Comaniciu, V. Ramesh, and P. Meer, IEEE Trans. Pattern Analysis and Machine Intelligence 25, 564 (2003).

[4] [4] Z. Liu and J. Yang, Chin. Opt. Lett. 2, 390 (2004).

[5] [5] S. Birchfield, in Proceedings of IEEE International Conference on Computer Vision and Pattern Recognition 232 (1998).

[6] [6] T. Xiong and C. Debrunner, in Proceedings of the Conference on Analysis of Images and Patterns 190 (2003).

[7] [7] B. Kwolek, in Proceedings of the 8th European Conference on Computer Vision 192 (2004).

[8] [8] M. Spengler and B. Schiele, Machine Vision and Applications 14, 50 (2003).

[9] [9] D. P. Huttenlocher, G. A. Klanderman, and W. J. Rucklidge, IEEE Trans. Pattern Analysis and Machine Intelligence 15, 850 (1993).

[10] [10] L. X. Wang, IEEE Trans. Fuzzy System 1, 146 (1993).

[11] [11] V. D. M. Rudolph, D. Arnaud, D. F. Nando, and W. Eric, CUED/F-INFENG/TR 380, 1 (2000).

[12] [12] The image sequences are available at http://vision.stanford.edu/~birch/.