Laser-based distance measurement using picosecond resolution time-correlated single-photon counting

In this paper, we report results obtained with a time-of-flight ranging/sca nning system based on time-correlated single-photon counting. This system u ses a pulsed picosecond diode laser and detects the scattered signal from a non-cooperative target surface using a semiconductor single-photon detecto r. A demonstration system has been constructed and used to examine the dept h resolution obtainable as a function of the integrated number of photon re turns. The depth resolution has been examined for integrated photon returns varying by five orders of magnitude, both by obtaining experimental measur ements and by computer simulation. Depth resolutions of approximately 3 mm were obtained for only ten returned photons. The effect of the background s ignal, originating either from temporally uncorrelated light signals or fro m detector noise, has also been examined.