OPTICAL DISPLACEMENT GAGE

摘要

PROBLEM TO BE SOLVED: To provide an optical displacement gage capable of rapidly setting or resetting optimum measurement conditions when measurement is started or when an object of measurement is changed for another. SOLUTION: This optical displacement gage has a light projecting means including a light emitting device for forming a light spot for measurement on the object of measurement, a light receiving means including a photographing element for photographing the object with the light spot formed thereon from a prescribed angle, and a computing means for computing objective displacement based on positional information on a light spot image in a picture obtained from the receiving means. This gage is further equipped with a characteristic extracting means for extracting image characteristics having a correlation with the size of the image signal of the spot image from the picture obtained from the receiving means and a control means for appropriately controlling the size of the image signal of the spot image used for the displacement computation by operating a light projection gain adjusting element of the projecting means and/or a light receiving gain adjusting element of the receiving means based on comparison of the extracted image characteristics with specified reference values.