摘要 |
<p>Distance measurement methods and apparatus use laser pulse sets having signatures which enable returned pulses to be correlated with emitted pulses. Each pulse set comprises at least one pulse and a signature selected from a set of possible signatures. Pulse sets reflected from at least one surface are detected and, for each set, the signature is recognized and a time of flight is determined. Signatures are defined by one or more of: spacing in time between pulses of a set, wavelength of the at least one pulse of the set, spacing in time between a first subset of a set and a second subset of a set, difference of wavelength between pulses of a set, and difference of wavelength between a first subset of a set and a second subset of a set. Each set can have multiple groups of pulses and pulses within a group can have different amplitudes.</p> |