ABSTRACT

This work aims at non-destructive detection of surface and subsurface defects in metallic specimens (e.g. railway track components) via pulsed inductive thermography in a moving setup. A new approach for scanning with changing speed has been developed to enable manual scanning of components in track. A steel specimen is heated with an inductor, and the surface temperature, including its variation over time, is recorded with an infrared camera. The infrared sequence is evaluated by Fourier transform to phase image, in order to increase the image quality. The proposed method uses a referencing object with AprilTags visible in each frame, allowing an adjustment by image registration. Changes in velocity during the scanning process are possible, as demonstrated by a manually performed scan of the specimen and the corresponding evaluation. Results obtained with different infrared cameras and scanning speeds were condensed into an estimation of the maximum scanning speed for a given camera specification.

摘要

这项工作旨在通过移动装置中的脉冲感应热成像技术对金属样本（例如铁路轨道部件）的表面和亚表面缺陷进行无损检测。已经开发出一种以变化的速度进行扫描的新方法，以实现对轨道中组件的手动扫描。用感应器加热钢样品，并用红外摄像机记录表面温度，包括其随时间的变化。红外序列通过傅立叶变换对相位图像进行评价，以提高图像质量。所提出的方法使用在每个帧中都可见的 AprilTags 的参考对象，允许通过图像配准进行调整。在扫描过程中速度的变化是可能的，如手动执行的样本扫描和相应的评估所证明的那样。