Patent ID: 6583861
Filing Date: 2003-06-24
Classification: G01C,G02B

Abstract:
A rangefinder apparatus comprising:light-projecting means for projecting a light beam toward a target object, located at a distance to be determined, a plurality of times; light-detecting means for detecting light of the light beam reflected from the target object and outputting a signal corresponding to the distance to the target object; signal processing means charging or discharging an integrating capacitor according to the signal output by said light-detecting means and outputting an integrated signal according to voltage of the integrating capacitor; detecting means for detecting the voltage of the integrating capacitor before rangefinding; and a central processing unit (CPU) controlling said light-projecting means, said light-detecting means, and said signal processing means, wherein, before rangefinding, said CPU controls said signal processing means to discharge the integrating capacitor, said CPU controls said detecting means to detect the voltage of the integrating capacitor after discharging of the integrating capacitor, and, when the voltage of the integrating capacitor detected by said detecting means is outside a fixed range, said CPU prevents said light-projecting means from projecting the light beam toward the target object.