Patent ID: 6501910
Filing Date: 2002-12-31
Classification: G02B

Abstract:
A camera distance measuring device, comprising:brightness determination means for determining brightness of a photographic object; first illumination means for illuminating a range containing at least a photography range of the camera; second illumination means for illuminating a part of the range contained within said photography range of the camera; at least a pair of integral light receiving means having a plurality of pixels and fixed light elimination means corresponding to said respective pixels; integration mode switching means for switching an integration mode of said integral light receiving means by controlling an operative state of said first illumination means, said second illumination means and said fixed light elimination means; calculating means for finding the distance to the photographic object based on object image signals obtained by said integral light receiving means; and distance measuring inability judgment means for determining whether it is possible to measure the distance by judging the reliability of the output of said calculating means; wherein, when said brightness determination means determines that the photographic object is bright, distance is measured in a first distance measuring mode by said integration mode switching means making said first illumination means, said second illumination means and said fixed light elimination means inoperative, said integral light receiving means integrating at a first integration mode, and said calculating means finding the distance to the photographic object based on the obtained object image signals; wherein, when said brightness determination means determines that the photographic object is dark, distance is measured in a second distance measuring mode by said integration mode switching means making said second illumination means inoperative and making said first illumination means and said fixed light elimination means operative, said integral light receiving means integrating in a second integration mode, and said calculating means finding the distance to the photographic object based on the obtained object image signals; and wherein, when said distance measuring inability judgment means judges the reliability of the distance to the photographic object sought with said calculating means and determines that distance measuring is impossible, distance is measured in a third distance measuring mode by said integration mode switching means making said first illumination means inoperative and making said second illumination means and said fixed light elimination means operative, said integral light receiving means newly integrating in the second integration mode, and said calculating means finding the distance to the photographic object based on the obtained object image signals.