Abstract During corrugated-plate manufacturing and associated service processes, the plates are often prone to suffering from defects such as cracks, holes and thinning. However, traditional inspection methods cannot effectively satisfy real-time requirements owing to the complexities of the examined surfaces. To solve this problem, this study develops a differential laser triangulation method based on online detection of variations in wall thicknesses, to identify surface defects (holes and thinning). This integrated system drives a pair of laser triangulation probes to capture the surface data of the plates. To compensate for the measurement errors of the triangulation probe caused by irregular surface curvatures, an empirical error model based on error evaluation is established. To improve the precision of the cross-sectional contour reconstruction, the corrected point data are segmented according to the geometrical characteristics of the examined plates, and the analytical model of the contour data in each subsection is modeled using the least-squares method. The wall thickness of each point can then be calculated using its normal equation, to characterize the surface defects. Experiments on a 203 mm × 176 mm workpiece demonstrate that the developed method not only analyzes the object dimensions, but also provides a non-destructive means to effectively detect defects on the surface of a corrugated plate.

中文翻译：

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使用差分激光三角测量法检测波纹板表面的缺陷

摘要 在瓦楞板制造及相关服务过程中，瓦楞板容易出现裂纹、孔洞、减薄等缺陷。然而，由于被检表面的复杂性，传统的检测方法不能有效地满足实时性要求。为了解决这个问题，本研究开发了一种基于壁厚变化在线检测的差分激光三角测量方法，以识别表面缺陷（孔洞和变薄）。该集成系统驱动一对激光三角测量探头来捕获板的表面数据。为补偿不规则表面曲率引起的三角测量仪测量误差，建立了基于误差评估的经验误差模型。为提高截面轮廓重建的精度，根据被检板材的几何特征对校正后的点数据进行分割，并采用最小二乘法对各分段轮廓数据的解析模型进行建模。然后可以使用其正常方程计算每个点的壁厚，以表征表面缺陷。在 203 mm × 176 mm 工件上的实验表明，所开发的方法不仅可以分析物体尺寸，而且还提供了一种有效检测波纹板表面缺陷的无损手段。然后可以使用其正常方程计算每个点的壁厚，以表征表面缺陷。在 203 mm × 176 mm 工件上的实验表明，所开发的方法不仅可以分析物体尺寸，而且还提供了一种有效检测波纹板表面缺陷的无损手段。然后可以使用其正常方程计算每个点的壁厚，以表征表面缺陷。在 203 mm × 176 mm 工件上的实验表明，所开发的方法不仅可以分析物体尺寸，而且还提供了一种有效检测波纹板表面缺陷的无损手段。