Active Microwave Thermography for Nondestructive Evaluation of Surface Cracks in Metal Structures

Foudazi, Ali; Mirala, Ali; Ghasr, Mohammad Tayeb; Donnell, Kristen M.

doi:10.1109/tim.2018.2843601

Cited by 38 publications

(16 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, the location of the anomaly can be identified clearly via the multi-frequency F DSE (r, m) because the magnitudes of several artifacts were reduced successfully. Throughout the theoretical and simulation results, we can examine that established structures (5) and (6) prove the main research question about the coupling effect and provide answers to some phenomena that cannot be explained via previous research, and various imaging results of F DSM (r, m) successfully support the theoretical result. Moreover, the established structures ( 5) and ( 7) illustrate the improvement in imaging performance, and various imaging results of F DSE (r, m) show not only the verification of theoretical results but also the stability.…”

Section: Simulation Results and Discussionmentioning

confidence: 58%

“…This is an old and difficult problem due to its intrinsic ill-posedness and nonlinearity [1]. Nevertheless, it is a very important problem to current scientists and engineers in developing reliable tools and techniques that can be applied to real-world problems such as medical imaging [2][3][4], damage detection in civil structure [5][6][7], radar imaging [8][9][10], etc. In order to solve this problem, various techniques have proposed various reconstruction algorithms.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Theoretical Identification of Coupling Effect and Performance Analysis of Single-Source Direct Sampling Method

Park¹

2021

Mathematics

View full text Add to dashboard Cite

Although the direct sampling method (DSM) has demonstrated its feasibility in identifying small anomalies from measured scattering parameter data in microwave imaging, inaccurate imaging results that cannot be explained by conventional research approaches have often emerged. It has been heuristically identified that the reason for this phenomenon is due to the coupling effect between the antenna and dipole antennas, but related mathematical theory has not been investigated satisfactorily yet. The main purpose of this contribution is to explain the theoretical elucidation of such a phenomenon and to design an improved DSM for successful application to microwave imaging. For this, we first survey traditional DSM and design an improved DSM, which is based on the fact that the measured scattering parameter is influenced by both the anomaly and the antennas. We then establish a new mathematical theory of both the traditional and the designed indicator functions of DSM by constructing a relationship between the antenna arrangement and an infinite series of Bessel functions of integer order of the first kind. On the basis of the theoretical results, we discover various factors that influence the imaging performance of traditional DSM and explain why the designed indicator function successfully improves the traditional one. Several numerical experiments with synthetic data support the established theoretical results and illustrate the pros and cons of traditional and designed DSMs.

show abstract

Section: Simulation Results and Discussionmentioning

confidence: 58%

Section: Introductionmentioning

confidence: 99%

Theoretical Identification of Coupling Effect and Performance Analysis of Single-Source Direct Sampling Method

Park¹

2021

Mathematics

View full text Add to dashboard Cite

show abstract

“…Active infrared thermography technology is a fast, noncontact detection method. The method can be divided into halogen lamp excitation [12], eddy current excitation [13], laser excitation [14], ultrasonic excitation [15], microwave excitation [16], resistive heating and mechanical vibrations excitation according to different heating excitation. And this method can be divided into reflection type and transmission type due to the different placement of the infrared imager.…”

Section: Iintroductionmentioning

confidence: 99%

Characterization Method of Surface Crack Based on Laser Thermography

et al. 2021

View full text Add to dashboard Cite

The characterization of micro cracks on metal surface plays an important role in the process of manufacturing and using, which has attracted a lot of attention. This is mainly due to the fact that the size of defects is smaller and the depth of defects is difficult to predict compared with metal materials with larger plane, which is still challenging. In order to solve this problem, this paper proposes a characterization method of surface defects based on reflective laser thermography, and designs a laser heating nondestructive testing system based on reflection. The system includes a semiconductor laser to heat the surface of metal cracks, and an infrared imager to record changes in the temperature field of the metal surface. In the process of data analysis, an Otsu adaptive threshold segmentation method is selected to quantify the defect size, which can control the quantification accuracy of defect size within 25%. A derivative analysis method is proposed to quantify the depth of defects, which can control the depth quantification accuracy of tiny defects within 7%.

show abstract

“…Infrared (IR) thermography is a non-contact Non-Destructive Testing (NDT) method and offers a robust and a rapid platform for inspection while covering a large area within a short time frame and thus potentially adaptable to in-service monitoring applications [1], [2] for electrical equipment [3], [4], mechanical equipment [5], welding [6], structural [7], [8] and aerospace composite materials [9]. However, in comparison with other NDT methods such as x-ray and ultrasound, thermography has a relatively low spatial resolution (typically 640 × 480 pixels).…”

Section: Introductionmentioning

confidence: 99%

The Spatial Resolution Enhancement for a Thermogram Enabled by Controlled Subpixel Movements

Addepalli

Zhao

2020

IEEE Trans. Instrum. Meas.

View full text Add to dashboard Cite

The measurement accuracy and reliability of thermography is largely limited by a relatively low spatial resolution of the thermal imager. Using a high-end camera to achieve high spatial resolution can be costly or infeasible due to a high sample rate required. Furthermore, the system miniaturisation becomes an inevitable trend with the continuous development of Internet of Things and their suitability to in-situ inspection scenarios. However, a miniaturised sensor usually suffers a low spatial resolution. Addressing this challenge, the paper reports a novel Spatial Resolution Enhancement for a Thermogram (SRE4T) system to significantly improve the spatial resolution without upgrading the sensor. A high-resolution thermal image is reconstructed by fusing a sequence of lowresolution images with sub-pixel movements. To achieve the best image quality, instead of benefiting from natural movements of existing studies, this paper proposes to use a high-resolution xy translation stage to produce a sequence of controlled sub-pixel movements. The performance of the proposed system was tested on both high-end and low-end thermal imagers. Both visual and quantitative results successfully demonstrated the considerable improvement of the quality of thermal images (up to 30.5% improvement of peak signal to noise ratio). This technique allows improving the measurement accuracy of thermography inspection without upgrading sensors. It also has the potential to be applied on other imaging systems.

show abstract

Active Microwave Thermography for Nondestructive Evaluation of Surface Cracks in Metal Structures

Cited by 38 publications

References 27 publications

Theoretical Identification of Coupling Effect and Performance Analysis of Single-Source Direct Sampling Method

Theoretical Identification of Coupling Effect and Performance Analysis of Single-Source Direct Sampling Method

Characterization Method of Surface Crack Based on Laser Thermography

The Spatial Resolution Enhancement for a Thermogram Enabled by Controlled Subpixel Movements

Contact Info

Product

Resources

About