A long-distance high-repetition-frequency laser three-dimensional scanning device based on coherent detection

Abstract

The invention discloses a long-distance high-repetition-frequency laser three-dimensional scanning device based on coherent detection, and the device comprises a frequency modulation signal generator (1), a narrow linewidth laser (2), an acoustic optical modulator (3), an optical frequency mixer (4), a balance detector (5), a low-pass filter (6), a scanning mirror (7), an angle coder (8), a coding counting circuit (9), a distance calculation modulation module (10), and a three-dimensional data processing module (11). The device carries out the linear modulation of laser frequency, enables the received laser echo to be coherent with reference light, and obtains a difference frequency signal of the layer echo and the reference light after photoelectric conversion. In each scanning circle, the absolute distance of a first scanning target point with an echo is calculated through difference frequency. The device carries out the integration of a distance change rate of rear scanning points with the reference of the absolute distance, and can calculate the line-of-sight distance and coordinates of a scanning track of a target surface. The device accurately calculates the distance change of a target through employing frequency measurement, and the repetition frequency of measurement is not limited by a fuzzy distance.

Description

technical field [0001] The invention relates to a laser three-dimensional imaging device, which can realize long-distance high-repetition-frequency laser three-dimensional imaging not limited by the fuzzy distance of distance measurement. Background technique [0002] In the field of laser radar and laser 3D scanner, the commonly used laser ranging methods mainly include phase measurement method and pulse direct ranging method based on time of flight. [0003] Phase measurement is mainly to achieve distance measurement by comparing the phase difference between the target echo and the reference signal, usually the distance range is 100m. The pulse time-of-flight ranging method uses narrow laser pulses with high peak power, which can achieve ranging and scanning over kilometers. However, because of the limitation of the round-trip time of the laser pulse flight, the distance limits the repetition frequency of the measurement. Taking the measurement distance of 1500m as an exa...

AI Technical Summary

Problems solved by technology

[0005] The technical solution of the present invention is to provide a long-distance high-repetition-frequency laser three-dimensional scanning device based on coherent detection, which can simultaneously have high sensitivity and high Measuring repetition frequency characteristics can realize long-distance high-repetition frequency laser three-dimensional imaging that is not limited by ambiguous distance

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