Visual Motion Detection Laura DeMar Jin Han Advisor: Professor Rudko

Introduction Motion Signals –Signals generated from a moving object –Vector containing direction and speed information Visual analysis of motion signals –Navigation –Collision avoidance –Object detection and recognition

Background History Gradient-Type Model –Originated from study of computer vision and later applied to biological motion vision – Mathematically obtains exact measurement of local velocity dx/dt Behavioural experiments on motion vision in insects –Wasps, bees, and flies

More Background history Bernhard Hassentein and Werner Reichardt –Founded Research Groupd of Cybernatics in 1958 in Tubingen, Germany –Did series of experiments to measure their behavoir –Glued Beetle to a rod to keep it from moving its body, head, and eyes relative to the surround –Beetle could express its behavoir at decision points Led to development of correlation-type motion detector model

Goal Model visual motion detection, specifically in lizards –Describe the neural computations of motion signals –Show Brain function in behavior control Use the correlation-type model.

Requirements of Motion Detectors At least two inputs Non-linear interaction between input signals Asymmetry –Two input signals need to be processed in a somewhat different way.

Correlation-type Motion Detector Signals come from two points in the retinal image Uses low pass filter to delay the brightness signal Compares signal by multiplication with instantaneous signal received from nearby location Subtract both outputs to subunit, giving the final output signal

Future Project Work motion detection on Lizards using simulated stimuli and using field data. Eliminate irrelevant motions caused by environmental motion –Wind-blown vegetation –Cloud movements and their shadows on land –Moving objects

Questions?