Biological Models of Motion Perception : Spatio-Temporal Energy Models and Electrophysiology

Van Santen and Sperling (1984) in their Elaborate Reichardt model introduce spatial receptive field profiles to prevent the spatial aliasing seen in the fly. This makes the response of the model zero for λ < 2∆x. Watson and Ahumada (1985) and Adelson and Bergen (1985) both propose models based on careful psychophysical measurements. The output can formally be expressed as a second-order interaction using the simplest type of nonlinearity possible, multiplication. Using psychophysics—which only has access to the final output of a system—none of these three models can be distinguished from each other. However, some of the internal stages different; in particular, the spatio-temporal energy model has a stage responding only to motion in one direction, while the correlation model has no such stage.