| 摘要 |
An optical time-of-flight rangefinder emits pulses of light at a pulse repetition interval (p.r.i.) (or pulse repetition frequency (p.r.f.)) which varies cyclically within a small range over a cycle time T. It receives reflections of the emitted pulses and evaluates time-of-flight for them over a plurality of measurement durations, each measurement duration being an integer or half-integer multiple of the p.r.i. cycle time T. Finally it converts time of flight into range. The average p.r.i. / p.r.f is kept constant over all the measurement durations of the set. The cyclic variation can be triangular, sawtooth or sinusoidal. The cycle time may be varied, for instance in accordance with the emitted light intensity. A time-of-flight camera may be used. The pulse length varies with the p.r.i. . An alternative version uses a sinusoidal signal. This is not described in any detail. |
