Enrico De Micheli Vincent Torre Sergio Uras The Accuracy of the Computation of Optical Flow and of the Recovery of Motion Parameters. 434-447 1993 15 IEEE Trans. Pattern Anal. Mach. Intell. 5 http://www.computer.org/tpami/tp1993/i0434abs.htm db/journals/pami/pami15.html#MicheliTU93