Patent ID: 7190402

Claim:
A visual sensor comprising: image capturing means for capturing two-dimensional images of an object with controllable exposure periods; reference light projecting means for projecting reference light; reference light control means for controlling ON/OFF of the light projection by said reference light projecting means; storage means storing magnification parameters for altering the exposure period in accordance with the ON/OFF state of the light projection exposure period control means for altering the exposure period by successively multiplying one of the magnification parameters stored in said storage means in accordance with the ON/OFF state of the light projection; image acquiring means for acquiring a plurality of two-dimensional images by said image capturing means with exposure periods altered by said exposure period control means in the ON/OFF state of reference light projection controlled by said reference light control means; and image processing means for producing a composite image having a characteristic of approximately a logarithm transformation based on a sum of densities of each pixel in the plurality of two-dimensional images acquired by said image acquiring means.