ELECTRONIC OPTICAL TARGET RANGING AND IMAGING

A system for optically ranging and three dimensionally imaging of an object. For ranging only a single photodetector can detect light reflected from the object when alternately illuminated by a pair of strobed sources or a shutter strobed direct and virtually imaged single source of light. The detector output signal for each illumination has the ambient only light intensity signal subtracted therefrom and the ratio of direct to virtually imaged light computed and the distance of the object determined from the ratio. For imaging an array of detectors is used and the computed distances mapped using the detector coordinates to give a three dimensional image. Light in the range 350 to 14000 manometers wavelength is preferred. The system is particularly suitable as a vehicle occupancy sensor and the image used to generate an airbag inflation suppression signal if the image indicates non-acceptable occupant characteristics or position.