Patent ID: 7535555

Claim:
A distance measurement device that measures a distance to an object, said distance measurement device comprising: a short pulse light source that generates and emits pulsed light at a short interval; a light divider unit that separates the pulsed light emitted by the short pulse light source into signal light and reference light; an irradiation and light-receiving unit capable of variations in azimuthal angle and elevation angle that irradiates the object with the signal light separated by the light divider unit and receives scattered light, which is reflected from the object irradiated with the signal light; a transmission time adjustment module that inputs the reference light separated by the light divider unit, adjusts a delay time of the reference light, and outputs the reference light of the adjusted delay time; an interference signal generation module that combines the reference light of the adjusted delay time output from said transmission time adjustment module with the scattered light received by the irradiation and light-receiving unit and generates an interference signal based on the combination of the reference light with the scattered light; a semi-transmissive mirror that allows the signal from the light divider to pass through, but reflects the scattered light from the object to the interference signal generation module; a distance computation module that computes a distance from a radiation point of the signal light to the object, based on the delay time of the reference light adjusted by said transmission time adjustment module and the interference signal generated by said interference signal generation module; and a wavelength change unit that varies a wavelength of the pulsed light emitted by the short pulse light source; wherein the light divider unit separates the pulsed light having the wavelength varied by the wavelength change unit into the signal light and the reference light, the wavelength change unit varies the wavelength of the pulsed light in order to achieve a peak interference signal, and said transmission time adjustment module adjusts the delay time of the reference light according to the varied wavelength of the reference light.