Tracking in the 1D case (x,1)1(x,1+1) emporal derivative P Spatial derivative Assumptions Brightness constancy ·Sma‖ motion9 v  x I Spatial derivative Temporal derivative t I Tracking in the 1D case: x I ( x , t) I ( x , t + 1) p t x x I I   = x p t t I I =   = x t I I v  −  Assumptions: • Brightness constancy • Small motion