Scanning inductive pulse phase thermography with changing scanning speed for non-destructive testing

Tuschl, Christoph; Oswald-Tranta, Beate; Agathocleous, timotheos; Eck, Sven

doi:10.1080/17686733.2023.2170159

Cited by 4 publications

(5 citation statements)

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“…Note that the spatial resolution of the resulting panoramic image is 12.18 pixels per mm, which is almost the same resolution as the original image. For the evaluation of the deblurred IR-sequence the same procedure is carried out, as presented in our previous work 9 . Figure 8 shows that the deblurred image sequence is first reordered to appear quasi-stationary.…”

Section: Discussionmentioning

confidence: 99%

“…A limiting factor for the scanning speed is the motion blur of the used cameras. In our previous work 9 we showed that IR-sequences recorded with a scanning speed up to 0.15 m/s lead to results with a good contrast between defects and sound surface. However, motion deblurring for VIS-cameras is more challenging, as described in the next subsection.…”

Section: Preparation and Measurementmentioning

confidence: 94%

“…Inductive thermography is a standardized NDT method, which is used for detection of surface defects in metal parts 1,2 . In recent years, the usage of inductive thermography for testing railway rails and turnout sections has also been investigated [3][4][5][6] . Short pulses from an inductor heat the component by a few degrees (∆T<10 K) and an infrared camera records the changes in the surface temperature before, during and after those pulses.…”

Section: Introductionmentioning

confidence: 99%

“…If speed is non-constant during a scan, the pixel-shift must be calculated individually for each frame. In our previous research 9 we presented a method, where a registration target with so called AprilTags 10 is visible in each frame of the sequence. This allows the registration of pixel-shifts from the image sequence directly without an external sensor.…”

Section: Introductionmentioning

confidence: 99%

“…During scanning, an IR-camera, as well as a VIS-camera record the same FOV. Based on the method shown in our previous work 9 a registration target with AprilTags is used to calculate pixel shifts for both recorded sequences. This information is used to evaluate the IRsequence via Fourier transform to phase image and to generate a panoramic view from the sequence recorded via VIScamera.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Scanning inductive thermography using a µ-bolometer and a visual camera

Tuschl

Agathocleous

Oswald-Tranta

et al. 2023

Thermosense: Thermal Infrared Applications XLV

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Scanning inductive thermography is a non-destructive inspection technique, which is suitable for detecting surface defects in long metallic work pieces. The work piece is moved below the inductor and the infrared (IR) camera, which is recording the surface temperature during the motion. To evaluate such measurements via phase image the recorded infrared image sequence must be reorganized according to the scanning speed. If the speed is not constant during the motion (e.g., due to manual scanning), visual fiducials (AprilTags) can be used in the camera’s field of view to register shifts between consecutive images. The main contribution of this work is image fusion, applied to scanning inductive thermography, combining the results of an infrared camera and a visual camera. An uncooled IR µ-bolometer camera with a thermal time constant of 8 ms is used for the infrared spectrum. Information of the motion speed during the scanning is acquired by the image registration, and it is used to deblur the IR image sequence before the evaluation to phase image via Fourier transform is performed. A second camera records the scanning process in the visual range. Using the AprilTags for registration, a panoramic view of the specimen is created. The results from both cameras are superimposed to improve the interpretation and localization of defects.

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Section: Discussionmentioning

confidence: 99%

Section: Preparation and Measurementmentioning

confidence: 94%