A low-power visual horizon estimation chip

Recent successes in micro-aerial vehicles (<15 cm length, wingspan, height), have highlighted the lack of real-time sensors for flight control. We describe a low-power, real-time visual horizon sensor for use in stabilizing miniature aircraft with respect to pitch and roll in moderate-to-high altitude flight. This prototype sensor incorporates a 12/spl times/12 photoreceptor array and finds a best-fit horizon line based on image intensity. The sensor includes a "confidence-level" output for a flight control system to detect poor sensing conditions. The chip was fabricated in a commercially-available 0.5 /spl mu/m CMOS process and operates on less than 2.5 milliwatts with a 5 V power supply.