基于双投射结构光系统的多尺度点云融合

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Multi-scale point cloud fusion based on dual-projection structured light system

JI Xiaofeng，LI Jianjun，NIU Jian，DENG Gaoxu* （College of Mechanical Engineering， Taiyuan University of Science and Technology， Taiyuan 030024，China） * Corresponding author，E-mail： denggaoxu@tyust. edu. cn

Abstract：Addressing the challenge of scale discrepancies between point clouds in dual-projected structured light systems，which hinder their direct fusion，this study presents a novel multi-scale point cloud fusion method. First，the dual-projected structured light system is calibrated to determine the intrinsic and extrinsic parameters of the cameras and projectors，along with the relative external parameters of the two systems. The weighted least squares phase expansion method is applied to extract the absolute phase，and point cloud data are computed using the calibrated parameters.Next，the spatial distances between any two points within the overlapping regions of the two systems are calculated to determine the relative scale factors，achieving scale unification between the point clouds. Coarse alignment is then performed using principal component analysis， followed by the derivation of the global optimal transformation matrix using an iterative nearest neighbor algorithm.The source point cloud is subsequently transformed to align with thetarget point cloud based on the calculated transformation matrix.Finally，the Euclidean distance is employed to evaluate the fused neighboring points，and outlier points are removed using a predefined threshold，ensuring accurate multi-scale point cloud fusion. Experimental results demonstrate that the standard deviation of the plane fitting error decreases by approximately 19.56% after fusion，validating the method’ s effectiveness in fusing point clouds and reconstructing object surfaces at varying scales. In conclusion， this research provides a robust solution for addressing scale-induced errors in dual-projected structured light systems and successfully mitigates missing data caused by occlusion.

Key words： structured light system；3D reconstruction； dual projection； point cloud fusion

1引言

随着三维测量技术在工业制造[1]、文物保护[2-3]、医学成像[4]等领域的广泛应用，高精度、高分辨率的三维点云数据成为关键需求。（剩余16152字）