• 한국세라믹학회지
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• 제43권4호
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• pp.259-263
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• 2006

The applicability of UPT (Ultrasound Pulse Thermography) for real-time defect detection of the ceramic heating plate is described. The ceramic heating plate with superior insulation and high radiation is used to control the water temperature in underwater environment. The underwater temperature control system can be damaged owing to the short circuit, which resulted from the defect of the ceramic heating plate. A high power ultrasonic energy with pulse duration of 280 ms was injected into the ceramic heating plate in the vertical direction. The ultrasound excited vibration energy sent into the component propagate inside the sample until they were converted to the heat in the vicinity of the defect. Therefore, an injection of the ultrasound pulse wave which results in heat generation, turns the defect into a local thermal wave transmitter. Its local emission is monitored and recorded via the thermal infrared camera at the surface which is processed by image recording system. Measurements were Performed on 4 kinds of samples, composed of 3 intact plates and the defect plate. The observed thermal image revealed two area of crack in the defective ceramic heating plate.

• 한국정보통신학회논문지
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• 제21권7호
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• pp.1429-1434
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• 2017

기존의 안경 렌즈 흠집 검출 방법은 영상내의 미세 잡음이 제거되지 않아 렌즈 영역이 정확히 추출되지 않는 경우가 발생하여 흠집 영역을 검출할 수 없다는 문제점이 발생한다. 따라서 본 논문에서는 이러한 문제점을 개선하기 위해 적응적 이진화 기법과 Bresenham algorithm을 적용하여 흠집 영역을 검출한다. 제안된 방법은 안경 렌즈 영상에서 명암 대비를 적용하여 렌즈의 명암을 강조한다. 명암이 강조된 영상에서 렌즈 밖의 배경 영역은 흠집 검출에 불필요하므로 이진화 기법을 적용한 후에 Bresenham algorithm을 적용하여 렌즈의 윤곽선을 검출하고 렌즈 이외의 배경을 제거한다. 렌즈 이외의 배경이 제거된 렌즈 영상에서 렌즈 내부의 배경과 흠집의 명암 대비를 높인다. 명암이 강조된 렌즈 내부 영역에서 적응적 이진화 기법을 적용하여 흠집과 잡음을 검출한다. 잡음은 중간값 필터를 적용하여 제거한 후에 흠집 영역을 추출한다. 추출된 흠집 영역에서 렌즈의 중심으로부터의 거리와 흠집의 크기를 퍼지 추론 규칙에 적용하여 눈에 미치는 영향 정도를 분석한다. 제안된 방법의 성능을 분석하기 위해 CHEMI, MID, HL, HM과 같은 시력 보정용 렌즈 영상을 대상으로 실험한 결과, 12개의 시력 보정용 렌즈 영상 중에서 10개에서 결함을 성공적으로 추출하였다.

• 반도체디스플레이기술학회지
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• 제22권2호
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• pp.81-86
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• 2023

Recently, there has been an increased demand for light-emitting diode (LED) due to the growing emphasis on environmental protection. However, the use of GaN-based sapphire in LED manufacturing leads to the generation of defects, such as dislocations caused by lattice mismatch, which ultimately reduces the luminous efficiency of LEDs. Moreover, most inspections for LED semiconductors focus on evaluating the luminous efficiency after packaging. To address these challenges, this paper aims to detect defects at the wafer stage, which could potentially improve the manufacturing process and reduce costs. To achieve this, image processing and deep learning-based defect detection techniques for Sapphire Epi-Wafer used in Green LED manufacturing were developed and compared. Through performance evaluation of each algorithm, it was found that the deep learning approach outperformed the image processing approach in terms of detection accuracy and efficiency.

• 대한안전경영과학회:학술대회논문집
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• 대한안전경영과학회 2004년도 춘계학술대회
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• pp.283-289
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• 2004

The number of pixel defects including bright and black dots on a panel is one of the critical factors determining the quality of TFT-LCD. Since pixel defects on the TFT-LCD panels are sometimes unavoidable, manufacturers have to inspect the panels so that any panel with an unacceptable number of defects will not be delivered to the buyers. However, the buyers demand for the manufacturers to meet different pixel defects tolerances (acceptable number of pixel defects on a TFT-LCD panel) around central(tight) and peripheral(loose) inspection zones. The disagreement in quality standard among different buyers also cause confusions in screening non-confirmative products and unstable yield of production. Few research has focused on the effects of defect locations on a TFT-LCD panel on their detection probabilities and the rational division of defect inspection zones. In this research, experiments were conducted to find the detection probabilities of black dot defects with respect to their varying locations on a TFT-LCD. It is proposed a rational division of inspection zone on a TFT-LCD panel on the basis of detection probabilities of the defects. With these division of inspection zones and the mean defect detection probability within each zone, it is expected to establish a more reasonable pixel defects tolerances.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.382-386
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• 2011

RFID 태그 생산 분야에서 RFID 칩 본딩 과정 이후에 RFID 태그 불량 검출 기능을 수행하는 불량 검출 시스템 개발이 요구되어 왔다. 그러나 RFID 태그의 특징을 이해하면서 제대로 된 설계 개념을 가지고 구현된 시스템을 설계하기가 어렵고 사소한 기능의 변화에도 시스템을 처음부터 설계를 해야 하는 어려움이 있었다. 이 논문에서는 RFID 태그 불량 검출 기능을 수행하는 불량검출 시스템을 UML을 이용하여 객체지향 기법으로 설계하고 UML로 설계된 모델링을 객체지향을 지원하는 비주얼 언어인 LabVIEW OOP로 적용하는 방법을 제시한다. UML과 LabVIEW OOP로 설계되고 구현된 불량검출 시스템에 대한 성능과 시스템의 기능 변화에 따른 재설계 기법에 대한 기법도 제안한다.

• 한국산업정보학회논문지
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• 제15권2호
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• pp.69-81
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• 2010

LCD 모니터의 백라이트로 CCFL 형광체를 많이 사용하고 있으나 그 불량여부는 육안에 의존하고 있다. 육안 검사를 함으로써 부품에 대한 일관성 있는 검사가 결여되고, 노동집약적인 검사로 인해 산업적 재해가 발생할 수 있다. 따라서, CCFL 불량유무를 판별하기 위해서 물리적 촬영 환경과 영상처리 알고리즘은 중요하다. 본 논문에서는 CCFL 형광체를 검사하기 위한 촬영환경에 대하여 설명하고, 촬영환경 중 돔 근거리 조명과 점원거리 조명에서의 몇 가지 불량판별 알고리즘을 제시하였다. 불량을 포함한 CCFL 형광체를 사용하여 실험을 수행하였고, 그 결과 제안한 촬영환경과 알고리즘은 불량 판별율 98.32 %와 과검율 4.88 %의 성능을 나타내었다.

• Nuclear Engineering and Technology
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• 제52권4호
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• pp.856-862
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• 2020

Defect inspection system for industrial applications takes the important portion. Non-destructive inspection method has been significantly improved. Infrared thermography, as one of method for non-destructive inspection, can provide relatively precise data and quick inspection time. This study, it was performed to measure defect according to the measurement limit of the non-visible areas such as the back surface of the pipe using reflection plate using reflection plate based on Infrared thermography. The materials of the reflection plate were determined in consideration of the space limitation and the thermal characteristics, and defects were detected by the manufactured reflection plate. Detection of defect in non-visible area using the candidate materials for reflection plate was conducted.

• 반도체디스플레이기술학회지
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• 제23권2호
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• pp.135-142
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• 2024

Cu-Cu bonding, one of the key technologies in advanced packaging, enhances semiconductor chip performance, miniaturization, and energy efficiency by facilitating rapid data transfer and low power consumption. However, the quality of the interface bonding can significantly impact overall bond quality, necessitating strategies to quickly detect and classify in-process defects. This study presents a methodology for detecting defects in wafer junction areas from Scanning Acoustic Microscopy images using a ResNet-50 based deep learning model. Additionally, the use of the defect map is proposed to rapidly inspect and categorize defects occurring during the Cu-Cu bonding process, thereby improving yield and productivity in semiconductor manufacturing.

• 한국정밀공학회지
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• 제26권11호
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• pp.55-61
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• 2009

The wall thinning defect of nuclear power pipe is mainly occurred by the affect of the flow accelerated corrosion (FAC) of fluid. This type of defect becomes the cause of damage or destruction of in carbon steel pipes. Therefore, it is very important to measure defect which is existed not only on the welding part but also on the whole field of pipe. This study use dual-beam Shearography, which can measure the out-of-plane deformation and the in-plane deformation by using another illuminated laser beam and simple image processing technique. And this study proposes Infrared thermography, which is a two-dimensional non-contact nondestructive evaluation that can detect internal defects from the thermal distribution by the inspection of infrared light radiated from the object surface. In this paper, defect of nuclear power pipe were, measured using dual-beam shearography and infrared thermography, quantitatively evaluated by the analysis of phase map and thermal image pattern.

• 동력기계공학회지
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• 제14권3호
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• pp.46-51
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• 2010

A torsional guided wave was applied to detect a defect in petrochemical pipes. Phase and group velocity dispersion curves for the longitudinal and torsional modes of the inspected pipe were presented for the theoretical analysis. It was found through mode shape analysis that there was mode conversion when torsional wave is incident at an asymmetric defect. An artificial notch was fabricated in the pipe and the detectability was examined from the distance 2m of the end of the pipe by using magnetostrictive sensors. The relativities between the amplitude of the reflected signal and the size of the defect was examined. It was shown that the T(0,1) mode could be used for the long range inspection for the petrochemical pipes.