Development of an IMU-Radar Sensor Board for Three-Dimensional Digital Image Correlation Camera Triangulation

摘要

In the last few years, advancements made in cameras technology, optically-based systems, and computer-aided methodshave made three-dimensional digital image correlation (3D-DIC) a robust tool for structural health monitoring (SHM) andextracting structural deformations and geometry profiles. To perform 3D-DIC measurements, the position of camerasrelative to each other must be determined. It is achieved by taking several pictures of calibration objects to determine thecamera’s extrinsic parameters (i.e., separation distance and orientation in space). This practice can be very cumbersomeand cameras calibration difficult to perform for large-sized structures. This is especially true if data is to be acquired frommultiple fields of view. This study describes the design of a MEMS-based sensor board to extend 3D-DIC’s capability andallow for easier calibration and measurement. The suggested system relies on a MEMS-based Inertial Measurement Unit(IMU) for determining the spatial orientation of the cameras (i.e., roll, pitch, and yaw angles) and a 77 GHz radar sensorfor measuring the relative distance of the stereo cameras. Both systems are integrated on a commercially availablemicrocontroller unit (MCU) that makes the system suitable for low-power applications. In this research, the efforts forprogramming the sensor board and the performance of the combined IMU-radar system in comparison with traditionalinstrumentation are described. To finish, the system is used for calculating the extrinsic parameters of a stereophotogrammetrysystem and results are compared with data obtained from a traditional calibration.