| 摘要 |
PURPOSE:To measure a range with high accuracy by projecting continuous pulse light on an object and detecting its reflected light beams as a ratio corresponding to the incidence position, and integrating two detected signals periodically and calculating the object range from the number of times of integration. CONSTITUTION:An IRED 2 is driven by a light emission driving circuit 12 to blink and project light beams. The reflected light beams from the object is photodetected by a PSD 5 and currents I1 and I2 flow to both terminals of the PSD 5 at the ratio corresponding to the object range. The currents I1 and I2 are converted by preamplifiers 13 and 14 into voltage signals, which are supplied to a BPF 17 through a channel changeover switch 15 for integration and a channel changeover switch 16 for reverse integration. The total number of times of integration performed by an integrator 17 is counted by a counter 27 and the number of times of positive-directional integration is counted by a counter 26. The object range is calculated according to the counted values of the counters 26 and 27. Thus, the S/N is improved and the high-accuracy range measurement is performed even when the range is relatively long. |
