Line-laser 3D scanning is a novel and promising automation technique for turbine blade inspection. One key task encountered in line-laser 3D scanning is centerline extraction of the laser stripes. In some regions, there is asymmetry of the line profiles caused by high curvature, such as the leading and trailing edges of a blade. According to the asymmetric Gaussian distribution line profile, this paper presents a new algorithm to extract the centerline of a laser stripe based on sub-pixel boundary extraction and medial axis transformation. The candidate boundary points of the laser stripe are extracted by zero crossing. Based on Taylor expansion and interpolation, the gray gradient distribution of the boundary can be estimated accurately. Following this, the accurate boundary points are extracted by extreme values of the gray gradient, and the centerline is calculated by medial axis transformation of the accurate boundary points. The proposed method can effectively reduce errors...

中文翻译：

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一种用于涡轮叶片检查的激光条纹中心线提取新算法

线激光3D扫描是用于涡轮叶片检查的一种新颖且很有前途的自动化技术。在线激光3D扫描中遇到的一项关键任务是激光条纹的中心线提取。在某些区域，由高曲率（例如叶片的前缘和后缘）引起的线轮廓不对称。针对非对称高斯分布线轮廓，提出了一种基于亚像素边界提取和中间轴变换的激光条纹中心线提取新算法。激光条纹的候选边界点通过零交叉提取。基于泰勒展开和插值，可以准确估计边界的灰度梯度分布。然后，通过灰度梯度的极值提取准确的边界点，中心线是通过精确边界点的中间轴变换来计算的。所提出的方法可以有效地减少错误...