High-Precision Line Laser Three-Dimensional Measurement Method Based on Telecentric Imaging

High accuracy three-dimensional (3D) imaging of precision components is vital for industrial manufacturing and inspection. To address the low efficiency and low accuracy of the existing line laser measurement system, a line laser three-dimensional measurement system using telecentric imaging is proposed herein, and the calibration method of the system is analyzed. First, target images of different positions and the same position under laser irradiation are obtained, and the relationship between the internal parameter matrix coefficient and external parameter pose of the camera is calibrated via telecentric orthogonal imaging. Subsequently, the geometric relationship between the line laser projection and calibration target planes is established, the laser line direction vectors under different target planes are solved, and the equation of the light plane is obtained via the least-squares method. The Levenberg-Marquard nonlinear optimization algorithm is used to accurately calculate the optimal solution of calibration parameters under the maximum likelihood criterion. Additionally, a test system and a calibration program are developed. Experimental results show that under a 60 mm x 48 mm field of view, the designed system can achieve a measurement accuracy of 18 mu m; furthermore, it can rapidly and accurately reconstruct the three-dimensional geometric model.