Distance measurement methods and apparatus

摘要

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.

主权项

1. A method of measuring distance comprising:
a. emitting a series of laser pulse sets, each emitted laser pulse set comprising at least two adjacent pulses and each emitted laser pulse set having a signature selected from a set of possible signatures, each of the possible signatures defined by one or more characteristics that enable discrimination between each emitted laser pulse set in the series of emitted laser pulse sets, wherein the signature is determined by at least one of (i) spacing in time between pulses of an emitted laser pulse set and (ii) a difference of amplitude between pulses of an emitted laser pulse set, b. detecting laser pulse sets as reflected from at least one surface, c. recognizing the signature of each detected laser pulse set by correlating the signature of each detected laser pulse set with the signature of one of the emitted laser pulse sets, and d. determining a time of flight for each of the detected laser pulse sets by referencing to a respective emitted laser pulse set having a matching signature.