Enhanced distance data acquisition

Abstract

A distance acquisition method comprising: initializing an optical ranging system, the optical ranging system including a plurality of pixels operable to covert incident light to electrical charges; collecting electrical charges with the plurality of exposed pixels over an integration time, each pixel collecting electrical charges with an amplification and a sensitivity; correlating the electrical charges collected in each pixel to an exposure value for each pixel, the exposure value corresponding to being adequately exposed, over-exposed, or under-exposed; identifying each exposure value for each pixel as being either valid or invalid, wherein a valid exposure value corresponds to an adequately exposed pixel and an invalid exposure value corresponds to an over-exposed or under-exposed pixel; totalling the number of valid exposure value pixels; totalling the number invalid exposure value pixels; determining an exposure ratio, the ratio being the number of pixels with valid exposure values divided by the number of pixels with invalid exposure values; totalling the number of over-exposed pixels; totalling the number of under-exposed pixels; determining an invalid exposure ratio, the invalid exposure ratio being the number of over-exposed pixels divided by the number of under-exposed pixels; and determining an average valid exposure value, the average valid exposure value being the average of the valid exposure values. The method additionally comprises: using the exposure ratio, the invalid exposure ratio and the average valid exposure to optimise the integration time; using the exposure value for each pixel to optimise the amplification and sensitivity for each pixel; and determining distance data from electrical charges collected from at least one of the plurality of pixels.