Analog integrated circuit for motion detection against moving background based on the insect visual system

A network for displaying the velocity signal of a target edge which has larger velocity than the background was proposed and designed based on an insect visual system. In the insect visual system, the velocity sipals generated by the background are inhibited by the signals generated by averaging the velocity signals from each cell and can only display the velocity signals of the target. The proposed network was constructed with simple analog circuits. The measured results of the test chip fabricated with the 1.2 mum complementary metal-oxide-semiconductor (CMOS) process showed that the edge detection circuit inserted to the first stage of the proposed network can detect the edge position. It was apparent from the measured results of the test circuit constructed with discrete rnetal-oxide-semiconductor (MOS) transistors that the proposed unit circuit constructing the network can generate the velocity signals by inputting the edge signals. The results with the simulation program with integrated circuit emphasis (SPICE) showed that the proposed network can only display the velocity signals of the target edges but not those of the background. Thus, it was clarified that the various motion directions of the target can be detected independent of the background by using the proposed network.