An Extremely Low-Power CMOS Glare Sensor

This paper describes a novel sense-and-respond optical sensor that is used to pinpoint glare in an image and produce a location specific response that can be used to reduce the discomfort or disability caused by the glare source. The sensor is a complimentary metal-oxide-semiconductor (CMOS) "smart" focal plane array (CFPA) chip that has 32times64 pixel resolution. Each pixel has a photodetector and simple signal processing circuitry consisting of a comparator and analog and digital readout. A pixel in the array is activated only when the light impinging on it is above a user-controllable threshold, which allows for extremely low levels of power consumption; the chip consumes approximately 51 muW of power when operating at 200 frames per second (fps) with a single 3 V dc supply. The CFPA has been successfully integrated with the microcontroller and liquid crystal display (LCD) glasses to form portable, lightweight, battery operated glare reduction glasses.