The authors report on a monitoring system for fiber laser fusion cutting based on a high-speed camera with spectral sensitivity in the visible spectral range. Without external illumination, the monitoring system is applied to a conventional cutting head with the optical detection path being coaxially aligned to the incident laser. It thus allows for the direct, spatially, and temporally resolved detection of the melt pool area in the cut kerf from the top view. The dependencies of the melt pool geometry on laser machining parameters can hence be evaluated. With different laser powers, feed rates, and assist gas pressures, incomplete cuts are forced in mild steel with sheet thicknesses ranging from 1 to 10 mm. The measured signal characteristics of the images captured from the melt pool are examined in the visible spectral range of the emitted, secondary thermal radiation from the process zone. Based on a specifically developed algorithm applied to the captured images, the authors are able to differentiate between complete and incomplete cuts with a distinguished detection probability of 94%.

中文翻译：

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一种高速相机监控光纤激光融合切割的图像处理算法的开发与评价

作者报告了一种基于高速相机的光纤激光融合切割监控系统，该相机具有可见光谱范围内的光谱灵敏度。在没有外部照明的情况下，监控系统应用于传统的切割头，其光学检测路径与入射激光同轴对齐。因此，它允许从顶视图直接、空间和时间分辨检测切割切口中的熔池区域。因此可以评估熔池几何形状对激光加工参数的依赖性。使用不同的激光功率、进给速率和辅助气体压力，在 1 到 10 毫米的薄板厚度范围内对低碳钢进行不完全切割。从熔池捕获的图像的测量信号特征在发射的可见光谱范围内进行检查，来自工艺区的二次热辐射。基于应用于捕获图像的专门开发的算法，作者能够区分完整和不完整的切割，区分检测概率为 94%。