Visual Motion Detection

1. Visual Motion Detection Laura DeMar Jin Han Advisor: Professor Rudko

2. 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

3. 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

4. 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

5. 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.

6. 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.

7. 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

9. 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

10. Questions?