Pipe segmentation technology for aircraft engines based on point cloud data
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摘要:
航空发动机通常布有大量自由弯曲、交错分布的管道,为避免运行中管道间的摩擦或共振引发故障,装配过程中需严格控制管道间距。然而,现有检测方法依赖人工操作,且存在劳动强度大、效率低、测量精度不稳定的问题。利用激光扫描仪采集航空发动机管道点云数据并进行间距计算,可以显著提高管道间距测量的自动化程度和效率。然而,航空发动机管道点云数据量庞大且分割困难,为后续的管道间距测量带来了挑战。因此,本研究以曲率、法向量夹角、法向量叉积三种关键特征作为分割判断条件,提出了一种基于层次化多特征的管道分割算法。计算结果表明,该算法通过逐层细化分割的方式精确分割出管道点云,改善了现有算法的过分割和欠分割问题,准确率达到了94.65%,为后续计算管道间距奠定了基础。
Abstract:Aero-engine usually has a large number of freely-bent and interlaced pipes. To avoid faults caused by friction or resonance between pipes during operation, the pipe spacing must be strictly controlled during assembly. However, the existing detection methods rely on manual operation and have problems such as high labor intensity, low efficiency, and unstable measurement accuracy. Using a laser scanner to collect point cloud data of aero-engine pipes and calculate the pipe spacing can significantly improve the degree of automation and efficiency of pipe spacing measurement. However, the point cloud data of aero-engine pipes is huge and difficult to segment, which brings challenges to the subsequent pipe spacing measurement. Therefore, a hierarchical multi-feature-based pipe segmentation algorithm is proposed by taking curvature, normal vector angle, and normal vector cross product as the segmentation judgment conditions. The calculation results show that this algorithm can accurately segment the pipe point cloud through a layer-by-layer refinement method, improving the over-segmentation and under-segmentation problems of existing algorithms, with an accuracy rate of 94.65%, which lays a foundation for subsequent pipe spacing calculation.
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表 1 点云数据信息
Table 1. Point cloud data information
数据编号 数据类型 点云数目 Engine data1 扫描数据 1310895 Engine data2 扫描数据 1170201 Model data 模型数据 6514650 表 2 不同点的曲率差异
Table 2. Curvature differences at different points
点类型 点云坐标 曲率 管道点 (−176.5, 42.8, 1673.8 )0.0048 (−175.1, 41.5, 1674.4 )0.0034 (−177.1, 42.3, 1674.4 )0.0045 (−174.1, 41.2, 1674.9 )0.0033 (−175.6, 41.6, 1674.5 )0.0027 (−175.1, 40.8, 1675.4 )0.0018 非管道点 (−167.5, 48.3, 1660.8 )0.0257 (−166.5, 48.3, 1660.9 )0.0405 (−169.1, 49.8, 1660.6 )0.0368 (−167.6, 48.8, 1660.7 )0.0328 (−167.5, 51.8, 1660.7 )0.0352 (−168.0, 53.7, 1660.8 )0.0281 表 3 消融实验的算法运行时间对比
Table 3. Comparison of ablation experiment running time
分割算法 运行时间/s 基于曲率 4.87 基于法向量夹角 15.122 基于法向量叉积 25.88 基于曲率+法向量夹角 14.35 基于曲率+法向量叉积 23.34 基于曲率+法向量夹角+法向量叉积 21.43 基于法向量夹角+曲率+法向量叉积 21.55 表 4 消融实验各算法性能对比
Table 4. Comparison of ablation experimental algorithms
分割算法 准确率/% 召回率/% F1分数/% 基于曲率 16.00 74.33 26.33 基于法向量夹角 27.54 88.80 42.04 基于法向量叉积 21.87 83.54 34.66 基于曲率+法向量夹角 37.43 74.33 48.36 基于曲率+法向量叉积 26.56 69.17 38.39 基于曲率+法向量夹角+
法向量叉积45.91 69.17 55.19 基于法向量夹角+曲率+
法向量叉积92.20 71.93 80.81 表 5 分割算法性能比较
Table 5. Performance comparison of segmentation algorithms
Methods 准确率(%) 召回率(%) F1分数(%) 层次化多特征分割 94.65 96.07 95.02 区域增长分割 76.87 71.06 72.33 欧式聚类分割 65.77 68.19 60.76 -
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