| 摘要 |
PURPOSE:To prevent the erroneous distance measurement at the boundary of an object to be measured by providing a means for screening the information on distance measurement which screens the distance measurement signal having the rate of fluctuation of a prescribed value or below as the effective information on the distance measurement. CONSTITUTION:Light begins to scan on the object to be measured when the user pushes a shutter button. The reflected light thereof is made incident on a semiconductor position detector 13 and the outputs A, B corresponding to the momentary incident position are produced from both output terminals of the detector 13. A divider circuit 20 calculates (A-B)/(A+B) and outputs the signal (distance measurement signal) corresponding to the distance up to the object to be measured. On the other hand, the output (A+B) of an adder circuit 18 is fed to a buffer amplifier 23. An analog switch 29 turns on and the signal from the circuit 20 is inputted to a capacitor 12 when the signal of a high level is outputted from an AND gate 28. The distance measurement signal while the signal light fluctuates largely during the scanning of the object to be measured (during the distance measurement operation) is neglected and therefore the exact information on the distance is held. |
