US 6,333,782 B2Granted

Distance measuring apparatus

AssigneeFuji Photo Optical Co., Ltd.

InventorYasuhiro Miwa

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Abstract

A distance measuring apparatus projects light toward an object at a distance to be measured, detects reflected light at a position according to the distance to the object to output a position signal, generates a distance computation value based on the position signal, integrates the distance computation value with an integrating capacitor, detects the distance, based on distance data corresponding to the integrated result, charges the integrating capacitor with a constant current for a time, and calculates a voltage for the integrating capacitor. In the distance measuring apparatus, the distance to the object is determined, based on a correction voltage calculated in a ranging routine, a reference voltage of the integrating capacitor calculated before the ranging routine, and the distance data. The apparatus reduces ranging error due to a change in the capacitance of the integrating capacitor.

Claims22

Dependent claims

A distance measuring apparatus comprising:

light projecting means for projecting a light beam toward an object at a distance to be measured;
light detecting means for detecting reflected light of the light beam projected toward and reflected from the object, at a reception position according to the distance to the object and outputting a position signal according to the reception position;
computing means for performing an operation based on the position signal from said light detecting means to generate a distance computation value according to the distance to the object;
integrating means comprising an integrating capacitor, said integrating means charging or discharging said integrating capacitor according to the distance computation value generated by said computing means to integrate the distance computation value;
detecting means for detecting the distance to the object, based on distance data corresponding to the distance computation value integrated in said integrating means;
charging means for charging said integrating capacitor by supplying a constant current for a fixed time;
and
voltage calculating means for calculating a voltage of said integrating capacitor after charging by said charging means, wherein said detecting means detects the distance to the object, based on a correction voltage calculated by said voltage calculating means in a ranging routine, a reference voltage of said integrating capacitor preliminarily calculated before executing the ranging routine, and the distance data.

5 more elements

A distance measuring apparatus comprising:

light projecting means for projecting a light beam toward an object at a distance to be measured;
light detecting means for detecting reflected light of the light beam projected toward and reflected from the object, at a reception position according to the distance to the object and outputting a position signal according to the reception position;
computing means for performing an operation based on the position signal output from said light detecting means to generate a distance computation value according to the distance to the object;
integrating means comprising an integrating capacitor, said integrating means charging or discharging said integrating capacitor according to the distance computation value generated by said computing means to integrate the distance computation value;
detecting means for detecting the distance to the object, based on distance data corresponding to the distance computation value integrated in said integrating means;
charging means for charging said integrating capacitor by supplying a constant current for a fixed time;
and
capacitance calculating means for calculating capacitance of said integrating capacitor after charging by said charging means, wherein said detecting means detects the distance to the object, based on a correction capacitance calculated by said capacitance calculating means in a ranging routine, a reference capacitance of said integrating capacitor preliminarily calculated before executing the ranging routine, and the distance data.

5 more elements

A distance measuring apparatus comprising:

light projecting means for projecting a light beam toward an object at a distance to be measured;
light detecting means for detecting reflected light of the light beam projected toward and reflected from the object, at a reception position according to the distance to the object and outputting a position signal according to the reception position;
computing means for performing an operation based on the position signal outputted from said light detecting means to generate a distance computation value according to the distance to the object;
integrating means comprising an integrating capacitor, said integrating means charging or discharging said integrating capacitor according to the distance computation value generated by said computing means to integrate the distance computation value;
detecting means for detecting the distance to the object, based on distance data corresponding to the distance computation value integrated in said integrating means;
charging means for charging said integrating capacitor to a predetermined voltage by supplying a constant current to said integrating capacitor;
and
charge time calculating means for calculating a time that elapses before a voltage of said integrating capacitor reaches the predetermined voltage, wherein said detecting means detects the distance to the object, based on a correction charge time calculated by said charge time calculating means in a ranging routine, a reference charge time of said integrating capacitor preliminarily calculated before executing the ranging routine, and the distance data.

5 more elements

Dependencies are inferred from the claim text.