A micro-power asynchronous contrast-based vision sensor wakes-up on motion

The presented demonstrator is capable of detecting a user-defined amount of motion in a scene with a limited energy-budget. This makes it suitable to be used as an energy-autonomous vision sensor for a wireless sensor network. It consists of a low-power contrast-based CMOS vision sensor interfaced with an FPGA and linked to a PC through the USB. The low-power vision sensor directly extracts the visual contrast of images in binary form and estimates the motion in the scene through a temporal matching, without dispatching any pixel outside the chip. The amount of moving pixels between two successive frames is computed by the sensor and compared outside the chip, with respect the a user-programmed value, by means of the FPGA, This low-power operating mode takes about 60μW at a frame rate of 50fps and does not occupy any data bandwidth.