A Novel Dynamic Light-Section 3D Reconstruction Method for Wide-Range Sensing

TL;DR

The paper tackles the trade-off between accuracy and range in galvanometer-based light-section 3D reconstruction by synchronizing laser scanning with camera FOV switching using multiple galvanometers. It introduces a complete geometric model and a three-tier calibration scheme (dynamic camera, dynamic laser, and joint calibration) to enable accurate 3D reconstruction over a wide range, validated by experiments achieving about $0.3$ mm accuracy over a $1100\times1300\times650$ mm volume and a range expansion by a factor of 25 at the same accuracy. Key innovations include the joint calibration approach and the parameterized mapping that ties pixel coordinates to world 3D points under dynamic scanning, as well as extensive verification on standard blocks and large objects. The work holds significant practical impact for industrial inspection and moving-target reconstruction, where both precision and coverage are essential.

Abstract

Existing galvanometer-based laser scanning systems are challenging to apply in multi-scale 3D reconstruction because of the difficulty in achieving a balance between high reconstruction accuracy and a wide reconstruction range. This paper presents a novel method that synchronizes laser scanning by switching the field-of-view (FOV) of a camera using multi-galvanometers. In addition to the advanced hardware setup, we establish a comprehensive mathematical model of the system by modeling dynamic camera, dynamic laser, and their combined interaction. We then propose a high-precision and flexible calibration method by constructing an error model and minimizing the objective function. Finally, we evaluate the performance of the proposed system by scanning standard components. The evaluation results demonstrate that the accuracy of the proposed 3D reconstruction system achieves 0.3 mm when the measurement range is extended to 1100 mm $\times$ 1300 mm $\times$ 650 mm. With the same reconstruction accuracy, the reconstruction range is expanded by a factor of 25, indicating that the proposed method simultaneously allows for high-precision and wide-range 3D reconstruction in industrial applications.

Figures (6)

• Figure 1: System design.
• Figure 2: Framework of dynamic 3D reconstruction method. (a) The flowchart of dynamic light-section 3D reconstruction. (b) Geometric modeling and calibration of dynamic 3D reconstruction system.
• Figure 3: 3D dynamic reconstruction system based on multiple galvanometers and light section.
• Figure 4: Calibration accuracy verification. (a) Error of dynamic camera transfer matrix. (b) Visualization of laser planes and the calibrated rotation axis. (c) Error curve before and after correction.
• Figure 5: Standard blocks reconstruction test at different angles. (a) The point clouds of the stair at different angle. (b) 3D reconstruction error distribution at different angles.