Three dimensional orientation signatures with conic kernel
 @Article{yu03ivc,
  author = 	 {W. Yu and G. Sommer and K. Daniilidis},
  title = 	 {Three dimensional orientation signatures with conic kernel filtering for multiple motion analysis},
  journal = 	 {Image and Vision Computing},
  year = 	 2003,
  volume =	 21,
  number =	 5,
  pages =	 {447-458}
}