NS-MD: Near-Sensor Motion Detection with Energy Harvesting Image Sensor for Always-On Visual Perception

With the rapid development of Internet-of-Things (IoT), self-powered visual perception systems attract lots of attention. This brief presents a near-sensor motion detection architecture for the energy harvesting image sensor targeting always-on monitoring applications. Reconfigurable pixel structures are designed to harvest solar energy from the focal plane and conduct motion detection simultaneously. The near-sensor motion detection architecture combining analog-domain edge detection and digital-domain frame differencing technique is proposed to reduce the power consumption on data conversion significantly. A prototype chip of 32× 32 array size is fabricated with the standard 0.18mu.m CMOS process CMOS process. The measurement results show that the chip prototype achieves motion detection at a frame rate of 1894 fps consuming 16.43~μ {W} power. Furthermore, the chip harvests 1.263~μ {W} power under 100kLux illumination, and the analytical computation result shows that self-powered motion detection can be achieved at a frame rate of 58 fps.