Multi-ring Beam Sensing System for Three-dimensional Measurement of the Narrow Inner Surface Profiles

In this paper, a multi-ring beam sensor is proposed which can measure the tilt angle, thereby further compensating the measured value of the pipe diameter. For the inner surface structure with a depth-to-diameter ratio far greater than 2:1, we use the relay imaging system as the imaging system of the sensor to increase the measurement field of view as well as improve the measurement reachability of the sensor equipment. The sensor has the ability to access irregular inner surface profiles features, realizing a wide range of measurements (determined by the field of view of the relay imaging system) and a measurement accuracy of 50μm and a repeatability of 15μm.