A two-dimensional motion detector based on insect vision

Implementing motion detection algorithms using analog VLSI techniques has proven to be a challenging task due to several obstacles, including the limitations of analog VLSI, the algorithmic limitations brought forward by complex motion detection schemes, and the effect of various types of noise. Insect vision has been an inspiring model for motion detectors, as insects heavily rely on motion detection for navigation, and the natural complexity of their neuro-visual circuitry is also less than that of vertebrates. In an effort to implement the so called template model of insect vision, a comparative study of various analog differentiators was undertaken by implementing different candidates on a test chip. Based on the results, a 64 by 4 motion detector has been designed and fabricated. The chip is designed in a 0.8 micrometer 3M-1P CMOS process, and the 2-D array occupies an area of 1.5 multiplied by 3.1 mm². Each cell comprises a bipolar-mode photodetector, an adaptive amplifier, the improved analog differentiator, and thresholding circuits.