Defect Recognition and Morphology Operation in Binary Images Using Line-Scanning-Based Induction Thermography

Lee, Seungju; Chung, Yoonjae; Kim, Wontae

doi:10.3390/app12126006

Cited by 7 publications

(4 citation statements)

References 43 publications

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“…The Otsu algorithm was proposed by OTSU N in 1979 [ 40 ]. It is mainly applied to digital image segmentation [ 41 , 42 ], and its main idea is to divide the image into foreground and background parts by using a threshold [ 43 , 44 , 45 ], to maximize the variance between foreground and background. Suppose the segmentation threshold is

, the proportion of foreground pixels is

, the average gray level is

, the proportion of background pixels is

, the average gray level is

, the total average gray level of the image is

, and the variance between-cluster is

, then:

…”

Section: Principle and Methods Of Mtf Measurementmentioning

confidence: 99%

MTF Measurement by Slanted-Edge Method Based on Improved Zernike Moments

Zhang¹,

Wang²,

Wu³

et al. 2023

Sensors

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The modulation transfer function (MTF) is an important parameter for performance evaluation of optical imaging systems in photogrammetry and remote sensing; the slanted-edge method is one of the main methods for measuring MTF. To solve the problem of inaccurate edge detection by traditional methods under the conditions of noise and blur, this paper proposes a new method of MTF measurement with a slanted-edge method based on improved Zernike moments, which firstly introduces the Otsu algorithm to automatically determine the Zernike moment threshold for sub-pixel edge detection to precisely locate the edge points, then obtains LSF through edge point projection, ESF sampling point acquisition, smoothing, fitting, taking ESF curve differential and Gaussian fitting, and finally, accurately obtaining MTF by LSF Fourier transform and modulo normalization. Based on simulation experiments and outdoor target experiments, the reliability of the proposed algorithm is verified by the deviations of slanted-edge angle and MTF measurement, and the tolerance degree of edge detection to noise and ambiguity are analyzed. The results show that compared with ISO 12233, OMNI-sine method, Hough transform method and LSD method, this algorithm has the highest edge detection accuracy, the maximum tolerance of noise and ambiguity, and also improves the accuracy of MTF measurement.

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, the proportion of foreground pixels is

, the average gray level is

, the proportion of background pixels is

, the average gray level is

, the total average gray level of the image is

, and the variance between-cluster is

, then:

…”

Section: Principle and Methods Of Mtf Measurementmentioning

confidence: 99%

MTF Measurement by Slanted-Edge Method Based on Improved Zernike Moments

Zhang¹,

Wang²,

Wu³

et al. 2023

Sensors

View full text Add to dashboard Cite

show abstract

“…In order to classify intensity values, the optimal threshold value must be calculated [ 29 , 30 ]. If it is an M × N image with L intensity levels such as 0, 1, 2, …, L−1, pixels with intensity values within [0, k] are classified as class 1, and intensity values within [k + 1, L + 1] are classified as class 2.…”

Section: Theorymentioning

confidence: 99%

Automatic Thinning Detection through Image Segmentation Using Equivalent Array-Type Lamp-Based Lock-in Thermography

Lee

Chung

Kim³

et al. 2023

Sensors

Self Cite

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Among the non-destructive testing (NDT) techniques, infrared thermography (IRT) is an attractive and highly reliable technology that can measure the thermal response of a wide area in real-time. In this study, thinning defects in S275 specimens were detected using lock-in thermography (LIT). After acquiring phase and amplitude images using four-point signal processing, the optimal excitation frequency was calculated. After segmentation was performed on each defect area, binarization was performed using the Otsu algorithm. For automated detection, the boundary tracking algorithm was used. The number of pixels was calculated and the detectability using RMSE was evaluated. Clarification of defective objects using image segmentation detectability evaluation technique using RMSE was presented.

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“…Lee et al [16] performed defect detection on the subsurface of the STS304 metal specimen by applying the line-scanning method to induction thermography. Liang et al [17] used eddy current pulsed thermography (ECPT) to detect rolling contact fatigue (RCF) cracks in the rail. Tu et al [18] proposed a method based on ECPT combined with feature extraction transform algorithms for transient thermal pattern separation and defect detection in composite insulators with internal conductive defects.…”

Section: Introductionmentioning

confidence: 99%

Theoretical and Numerical Study of Eddy Current Pulsed Thermography to Detect Damage of Deep-Sea Manned Pressure Hull

Zhang

Wang

et al. 2023

JMSE

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At present, research on pressure hull safety is mainly focused on the constitutive model of material properties and the evaluation model of structural parameters aiming at fatigue life prediction. The damage identification and quantitative evaluation methods of pressure hulls have not been studied. In this study, an eddy current thermal imaging method is introduced to detect micro-cracks in a deep-sea spherical pressure hull. In the detection method, temperature is used as a parameter to identify and quantify cracks. The temperature distribution around the cracks is studied using theoretical analysis and finite element simulation. A theoretical model is established using electromagnetic theory and heat transfer theory. Moreover, the temperature difference between the cracked area and the non-cracked area can be obtained by solving the heat conduction equation. A pulsed eddy current thermal imaging testing system is established, and a defective titanium alloy specimen is tested. At the same time, the temperature around the cracks in the specimens is simulated. The specimens have the same material and welding as a deep-sea spherical pressure hull. This paper discusses the possibility of its use in a pressure hull, which will provide a reference for micro-crack damage identification and quantitative evaluation of a deep-sea spherical pressure hull.

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Defect Recognition and Morphology Operation in Binary Images Using Line-Scanning-Based Induction Thermography

Cited by 7 publications

References 43 publications

MTF Measurement by Slanted-Edge Method Based on Improved Zernike Moments

MTF Measurement by Slanted-Edge Method Based on Improved Zernike Moments

Automatic Thinning Detection through Image Segmentation Using Equivalent Array-Type Lamp-Based Lock-in Thermography

Theoretical and Numerical Study of Eddy Current Pulsed Thermography to Detect Damage of Deep-Sea Manned Pressure Hull

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