Tunnel three-dimensional imaging method and system

The present invention discloses a tunnel three-dimensional imaging method and system, and belongs to the technical field of traffic tunnel detection imaging. The laser scanning is combined with the ultrasonic fault detection technology, a mode that the relative position of a laser scanning imager and an ultrasonic transducer remains stationary and the optical axis of the laser scanning imager is parallel with the sound wave emission direction of the ultrasonic transducer is employed to measure the relative position of the ultrasonic transducer and the laser scanning imager, convert one-dimensional data represented by the reflection signals detected by the ultrasonic transducer, namely a depth result of a reflection surface to three-dimensional coordinates of the reflection surface and allow the three-dimensional coordinates of the reflection surface to correspond to the coordinate data of a tunnel surface point cloud model so as to integrate the three-dimensional coordinates of the reflection surface and the