A fast and precise three-dimensional measurement system based on multiple parallel line lasers

This paper conducts a trade-off between efficiency and accuracy of three-dimensional (3D) shape measurement based on the triangulation principle, and introduces a flying and precise 3D shape measurement method based on multiple parallel line lasers. Firstly, we establish the measurement model of the multiple parallel line lasers system, and introduce the concept that multiple base planes can help to deduce the unified formula of the measurement system and are used in simplifying the process of the calibration. Then, the constraint of the line spatial frequency, which maximizes the measurement efficiency while ensuring accuracy, is determined according to the height distribution of the object. Secondly, the simulation analyzing the variation of the systemic resolution quantitatively under the circumstance of a set of specific parameters is performed, which provides a fundamental thesis for option of the four system parameters. Thirdly, for the application of the precision measurement in the industrial field, additional profiles are acquired to improve the lateral resolution by applying a motor to scan the 3D surface. Finally, compared with the line laser, the experimental study shows that the present method of obtaining 41220 points per frame improves the measurement efficiency. Furthermore, the accuracy and the process of the calibration are advanced in comparison with the existing multiple-line laser and the structured light makes an accuracy better than 0.22 mm at a distance of 956.02 mm.