Effects of compressive nonlinearity on insect-based motion detection

Motion detection and velocity estimation systems based on the study of insects tries to emulate the extraordinary visual system of insects with the aim of coming up with low power, computationally simple, highly efficient and robust devices. The Reichardt correlator model is one of the earliest and the most prominent models of motion detection based on insect vision. In this paper we try to extend the Reichardt correlator model to include an additional non-linearity which has been seen to be present in the fly visual system and we study its effect on the contrast dependance of the response and also try to understand its influence on pattern noise. Experiments are carried out by adding this compressive non-linearity at different positions in the model as has been postulated by previous works and comparison of the physiological data with modelling results is done.