Tomohiro Mashita Yoshio Iwai Masahiko Yachida Calibration of HyperOmni Vision based on Conic Curve. 51-54 2005 MVA http://b2.cvl.iis.u-tokyo.ac.jp/mva/proceedings/CommemorativeDVD/2005/papers/2005051.pdf conf/mva/2005 db/conf/mva/mva2005.html#MashitaIY05