ADJUSTING METHOD FOR OUTPUT GAIN OF PHOTOSENSOR FOR SHAPE MEASURING INSTRUMENT

• Main Authors: TAKAGAWA YUKIO, ENDO MOTONORI
• Format: Patent
• Language: English
• Published: 18.06.1990
• Subjects: MEASURING; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS; MEASURING LENGTH, THICKNESS OR SIMILAR LINEARDIMENSIONS; PHYSICS; TESTING

PURPOSE:To adjust the output gain of the photosensor automatically without causing a decrease in measurement accuracy nor taking a long time by scanning an object first and recording the light reception range in the entire stroke, comparing the light reception range with a specific value, and adjusting the output gain according to the comparison result. CONSTITUTION:A measurement part 1 is equipped with a laser light emitting device 6, a video camera 7 which incorporates a CCD linear sensor 7a, a reflecting mirror 9, and a motor 10 for scanning, the object 8 is scanned with luminous flux to find the movement quantity of a reflected light image in scanning from the output signal indicating the light reception quantity distribution of the image of reflected light, and the shape of the object is measured based upon the movement quantity. At this time, the object 8 is scanned at least once with the luminous flux through an adjusting device 11 to record the light reception range found from the light reception quantity distribution of the photosensor 7a in the entire stroke of the scanning. Then the recorded light reception range is compared with the specific value and the output gain of the photosesnor 7a is adjusted according to the comparison result. Thus, the output gain is adjusted properly and automatically.