| 摘要 |
PURPOSE:To measure distances over a wide range in a relatively short time with high accuracy without requiring any large-scale processing circuit by discriminating a large/small levels between output levels of two of three photodetectors and selecting a photodetector output to be inputted to an arithmetic means according to the decision result. CONSTITUTION:In addition to a processing circuit, this range finder is provided with changeover switches 1 and 3, an operational amplifier 5 which outputs the difference signal between output signals inputted from demodulators 2 and 4, i.e., an object signal for discriminating the large/small levels, a switch switching circuit 6 which switches changeover switches 117 and 118 with the signal from the operational amplifier 5, etc. Then it is judged which of the output levels of the photodetectors for, for example, an intermediate distance and a short distance is larger and when the output level of the intermediate- distance photodetector is larger, it is discriminated that an object of range finding is positioned on a long-distance side; and the long-distance photodetector and intermediate-distance photodetector are selected for the range finding and the outputs of those photodetectors are introduced to an arithmetic means. |
