scholarly journals Extension of the Thermographic Signal Reconstruction Technique for an Automated Segmentation and Depth Estimation of Subsurface Defects

2020 ◽  
Vol 6 (9) ◽  
pp. 96
Author(s):  
Alexander Schager ◽  
Gerald Zauner ◽  
Günther Mayr ◽  
Peter Burgholzer
Keyword(s):  
Signal Reconstruction ◽  
Computational Cost ◽  
Infrared Camera ◽  
Poor Performance ◽  
Depth Estimation ◽  
Reconstruction Technique ◽  
Destructive Testing ◽  
Cost Efficient ◽  
Non Destructive ◽  
Subsurface Defects

With increased use of light-weight materials with low factors of safety, non-destructive testing becomes increasingly important. Thanks to the advancement of infrared camera technology, pulse thermography is a cost efficient way to detect subsurface defects non-destructively. However, currently available evaluation algorithms have either a high computational cost or show poor performance if any geometry other than the most simple kind is surveyed. We present an extension of the thermographic signal reconstruction technique which can automatically segment and image defects from sound areas, while also estimating the defect depth, all with low computational cost. We verified our algorithm using real world measurements and compare our results to standard active thermography algorithms with similar computational complexity. We found that our algorithm can detect defects more accurately, especially when more complex geometries are examined.

A REVIEW ON EDDY CURRENT THERMOGRAPHY TECHNIQUE FOR NON-DESTRUCTIVE TESTING APPLICATION

2016 ◽  
Vol 78 (11) ◽  
Author(s):  
N. S. Rusli ◽  
I. Z. Abidin ◽  
S. A. Aziz
Keyword(s):  
Defect Detection ◽  
Eddy Current ◽  
Infrared Camera ◽  
Heat Diffusion ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Quantitative Characterisation ◽  
Optimum Heating ◽  
Non Destructive ◽  
Eddy Current Heating

Eddy current thermography is one of the non-destructive testing techniques that provide advantages over other active thermography techniques in defect detection and analysis. The method of defect detection in eddy current thermography has become reliable due to its mode of interactions i.e. eddy current heating and heat diffusion, acquired via an infrared camera. Such ability has given the technique the advantages for non-destructive testing applications. The experimental parameters and settings which contribute towards optimum heating and defect detection capability have always been the focus of research associated with the technique. In addition, the knowledge and understanding of the characteristics heat distribution surrounding a defect is an important factor for successful inspection results. Thus, the quantitative characterisation of defect by this technique is possible compared to the conventional non-destructive which only acquired qualitative result. In this paper, a review of the eddy current thermography technique is presented which covers the physical principles of the technique, associated systems and its applications. Works on the application of the technique have been presented and discussed which demonstrates the ability of eddy current thermography for non-destructive testing of conductive materials.   

Review on Non-Destructive Testing Technique of Eddy Current Pulsed Thermography

2015 ◽  
Vol 742 ◽  
pp. 128-131 ◽  
Author(s):  
Jian Min Zhou ◽  
Jun Yang ◽  
Qi Wan
Keyword(s):  
Eddy Current ◽  
Signal Reconstruction ◽  
Infrared Image ◽  
Principal Component ◽  
Research Progress ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Pulsed Thermography ◽  
Pulsed Phase Thermography ◽  
Non Destructive

This paper introduces the theory of eddy current pulsed thermography and expounds the research status of eddy current pulsed thermography in application and information extraction. Thermographic signal reconstruction, pulsed phase thermography, principal component analysis were introuduced in this paper and listed some fusion multiple methods to acquire information from infrared image. At last, it summarizes research progress, existing problem and deelopment of eddy current pulsed thermography.

scholarly journals Infrared Non-Destructive Testing via Semi-Nonnegative Matrix Factorization

Proceedings ◽  
2019 ◽  
Vol 27 (1) ◽  
pp. 13 ◽  
Author(s):  
Yousefi ◽  
Ibarra-Castanedo ◽  
Maldague
Keyword(s):  
Matrix Factorization ◽  
Nonnegative Matrix ◽  
Principal Component ◽  
Computational Time ◽  
Detection Accuracy ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Non Destructive ◽  
Non Negative Matrix Factorization ◽  
Subsurface Defects

Detection of subsurface defects is undeniably a growing subfield of infrared non-destructive testing (IR-NDT). There are many algorithms used for this purpose, where non-negative matrix factorization (NMF) is considered to be an interesting alternative to principal component analysis (PCA) by having no negative basis in matrix decomposition. Here, an application of Semi non-negative matrix factorization (Semi-NMF) in IR-NDT is presented to determine the subsurface defects of an Aluminum plate specimen through active thermographic method. To benchmark, the defect detection accuracy and computational load of the Semi-NMF approach is compared to state-of-the-art thermography processing approaches such as: principal component thermography (PCT), Candid Covariance-Free Incremental Principal Component Thermography (CCIPCT), Sparse PCT, Sparse NMF and standard NMF with gradient descend (GD) and non-negative least square (NNLS). The results show 86% accuracy for 27.5s computational time for SemiNMF, which conclusively indicate the promising performance of the approach in the field of IR-NDT.

scholarly journals Uncertainty Analysis of Infrared Thermography in Convective Heat Transfer

Volume 1 ◽  
2004 ◽  
Author(s):  
Nelson K. Akafuah ◽  
Carsie A. Hall ◽  
Ting Wang
Keyword(s):  
Heat Transfer ◽  
Temperature Measurement ◽  
Convective Heat Transfer ◽  
Infrared Thermography ◽  
Convective Heat ◽  
Infrared Camera ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Test Plate ◽  
Non Destructive

Infrared thermography is the preferred choice in many industrial processes for thermal diagnostics, condition monitoring, and non-destructive testing. However, the inherent uncertainty of surface emissivity affects the accuracy of temperature measurement by infrared thermography. In this paper a comprehensive experimental investigation was conducted to assess the uncertainty of infrared thermography in convective heat transfer. Four convective heat transfer conditions, including natural and forced convection on a flat plate, were studied. A composite test plate was constructed with an embedded heater and thermocouples. The thermocouples were used as references to compare with measurements by the infrared camera. The results indicate that the uncertainty of temperature measurement is about 4°F (2.7% of the wall-to-ambient temperature difference) with the largest uncertainty being contributed by calibration of the infrared camera. The uncertainty of the heat transfer coefficient is 4.2% which is largely contributed by wall temperature measurement.

Enhanced image processing for infrared non-destructive testing

2014 ◽  
Vol 22 (4) ◽  
Author(s):  
F. Lopez ◽  
X. Maldague ◽  
C. Ibarra-Castanedo
Keyword(s):  
Signal To Noise Ratio ◽  
Signal Reconstruction ◽  
Non Destructive Testing ◽  
Destructive Testing ◽  
Multivariate Statistical ◽  
Depth Analysis ◽  
Thermal Data ◽  
Signal Contrast ◽  
Pulsed Phase Thermography ◽  
Non Destructive

AbstractThis paper presents a review and in-depth analysis of three of the most popular techniques for processing PT images: differential absolute contrast, thermographic signal reconstruction and pulsed phase thermography. The fundamental concepts of the three techniques are reviewed and their application on thermal data obtained from the PT inspection on a carbon fibre reinforced specimen is analysed. Furthermore, a new promissory technique based on multivariate statistical analysis is also introduced and evaluated. The performance of the techniques is evaluated in terms of the signal-to-noise ratio at maximum signal contrast.

Scanning induction thermography for subsurface defect orientation detection and depth quantification

2020 ◽  
Vol 64 (1-4) ◽  
pp. 869-877
Author(s):  
Hui Xia ◽  
Erlong Li ◽  
Jianbo Wu ◽  
Qiao Qiu ◽  
Jie Wang ◽  
...  
Keyword(s):  
Eddy Current ◽  
Experimental Studies ◽  
Extraction Methods ◽  
Destructive Testing ◽  
Pulsed Eddy Current ◽  
Subsurface Defect ◽  
New Feature ◽  
Lock In ◽  
Non Destructive ◽  
Subsurface Defects

Pulsed eddy current thermography (PECT) and eddy current lock-in thermography (ECLIT) are non-destructive testing (NDT) techniques of high promising and interest in subsurface defect detection. In the previous researches, the induction coil was set above the defect region and it always parallel to the defect orientation. However, the location and orientation of subsurface defects cannot be determined before detection. Therefore, the scanning induction thermography (SIT) based on dynamic thermography is proposed by some researchers to localize and distinguish the subsurface defects. Still, the main challenges of SIT are how to detect the subsurface defect orientation and quantify the depth. So that, the quantitative analysis in SIT with the new feature extraction methods was investigated and improved to detect the subsurface defect orientation and quantify the defect depth within 5 mm by using experimental studies.

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