Analysis of Factors Influencing Accuracy in Line-Structured Light Three-Dimensional Surface Measurement Systems
Objective Line-structured light technology offers advantages such as simplicity,robustness,and non-contact measurement,making it widely used in industrial applications like reverse engineering,defect detection,and part alignment. In recent years,this method has garnered significant attention and research as a crucial three-dimensional vision measurement technique. However,variations in measurement range and accuracy exist due to differences in measurement objects,with key factors affecting accuracy stemming from the light source,camera,and scanning device of the line-structured light three-dimensional surface measurement system. The interplay among these system parameters presents challenges to researchers. Therefore,we delve into these aspects in this paper,conducting an in-depth study on the influence of component characteristics of structured light measurement on system performance and exploring the relationships among performance constraints. We aim to provide theoretical support for researchers and practitioners involved in constructing line-structured light vision systems.Methods Due to variations in measurement objects,the measurement range and accuracy vary accordingly. The precision of the line-structured light three-dimensional surface measurement system is mainly influenced by the light source,camera,and scanning device. This study focuses on analyzing and researching these aspects. It begins by introducing mathematical models of the non-Sham structured line-structured light sensor and the mathematical model for stitching point clouds from line-structured light scans. Subsequently,a detailed analysis is conducted on the impact of key component characteristics on system performance and the interdependencies of system performance. Factors such as the uniformity of brightness of the laser-projected light stripes,the straightness of the light stripes,laser line width,internal camera parameters,camera perspective imaging,motion errors of the scanning device,and the influence of scanning methods are individually analyzed. By elucidating the design rationale of key system parameters based on common detection needs,we provide theoretical support for optimizing system design. Finally,we establish a micrometer-level line structured light scanning measurement system and calibration experimental platform,enabling three-dimensional reconstruction experiments. This optimization process enhances the overall accuracy and efficiency of the system.Results and Discussions Based on the theoretical analysis and measurement system presented in this article,we conduct experiments on the three-dimensional reconstruction of various objects. Initially,we measure a gauge block and a standard ball to determine their dimensions. The gauge block,made of ceramic material,has a nominal length of 5 mm,while the standard ball,also ceramic,has a nominal radius of 5 mm with a maximum sphericity error of 0.5 μm. During the measurement of the gauge block,we stack both blocks together and measure the distance between their front surfaces to determine the length of the first block. This process is repeated 10 times,resulting in an average measurement error of 2.0 μm for the gauge block and 7.3 μm for the radius measurement of the standard ball. Additionally,we select a PCB board and M6 screws for our three-dimensional reconstruction experiment. The choice is influenced by the widespread use of PCB boards in current line-structured light systems. Both objects feature diverse surface textures and varying curvatures,which significantly impact our experimental results. As shown in Fig. 24,the experimental results demonstrate a good three-dimensional reconstruction effect for detailed features such as font prints and screw threads.Conclusions In this study,we analyze the factors influencing the measurement accuracy of line-structured light,with a focus on the roles of the light source,camera,and scanning device in the system's performance. By introducing mathematical models of line structured light sensors and point cloud stitching,we conduct a thorough analysis on the influence of key component characteristics on the system's performance and their interrelationships. Addressing common detection requirements,we expound the logical design of key system parameters,which provides theoretical support for system optimization. Finally,we establish a micron-level line structured light scanning measurement system and calibration experimental platform,followed by 3D reconstruction experiments. These valuable experimental data and insights advance line-structured light technology in practical applications. The research findings are poised to render crucial theoretical and practical support across various industries,which serve as beneficial references and guidance for engineers and researchers in related fields.
line-structured lightmachine visionthree-dimensional surface measurementanalysis of factors influencing accuracysystem optimization
NETL
NSTL
万方数据
