# Binocular Stereo Vision-Based Structured Light Scanning System Calibration and Workpiece Surface Measurement Accuracy Analysis

## TL;DR

This paper presents a structured light scanning system for high-precision measurement of large components in construction, addressing challenges like occlusion and calibration accuracy.

## Contribution

A multi-camera structured light system is developed for large-scale contour measurement with insights into calibration and error analysis.

## Key findings

- Structured light method shows better accuracy and speed compared to image and line laser methods.
- Multi-camera stitching improves contour measurement but still faces challenges in achieving stable millimeter-level accuracy.
- Repeated experiments with four scanners provided practical insights for future accuracy improvements.

## Abstract

Precise online measurement of large structural components is urgently needed in modern manufacturing and intelligent construction, requiring a measurement range over 1 m, near-millimeter accuracy, second-level measurement speed, and adaptability to complex environments. In this paper, three mainstream measurement technologies, namely the image method, line laser scanning method, and structured light method, are comparatively analyzed. The structured light method exhibits remarkable comprehensive advantages in terms of accuracy and speed; however, it suffers from the issue of occlusion during contour measurement. To tackle this problem, multi-camera stitching is employed, wherein the accuracy of camera calibration plays a crucial role in determining the quality of point cloud stitching. Focusing on the cable tightening scenario of meter-diameter cables in cable-stayed bridges, this study develops a contour measurement system based on the collaboration of multiple structured light cameras. Measurement indicators are optimized through modeling analysis, system construction, and performance verification. During verification, four structured light scanners were adopted, and measurements were repeated 11 times for the test workpieces. Experimental results demonstrate that although the current measurement errors have not yet been stably controlled within the millimeter level, this research provides technical exploration and practical experience for high-precision measurement in the field of intelligent construction, thus laying a solid foundation for subsequent accuracy improvement.