• Journal of the Korean Society for Precision Engineering
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• v.25 no.8
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• pp.21-28
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• 2008

Fizeau interferometer is used for inspecting the lens surface profile accurately. This study is focused on the design and optical measuring techniques for large optical components, such as a reflection mirror for large area lithography or astronomical purpose. A tower type Fizeau interferometer is designed and set up in horizontally with a 45$^{\circ}$ fold mirror which makes easy to align the optical path of heavy interferometer system. To align the optical path, a five-axes stage for the interferometer is required. This study shows a method of the 45$^{\circ}$ fold mirror alignment by using a three-axis stage instead of adjusting the interferometer itself or measuring object. This system will be installed on the large optics polishing machine during the manufacturing process as an on-machine inspection system.

• Proceedings of the Optical Society of Korea Conference
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• 2009.02a
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• pp.527-528
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• 2009

We developed the compact-sized ear inspector utilizing fiber-pigtailed cheap LED light source and CCD(charge coupled detector) camera. With adjusting the lens pair having different focal length respectively, optimized imaging conditions with fiber-coupled LED were obtained.

• 제어로봇시스템학회:학술대회논문집
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• 1996.10b
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• pp.796-799
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• 1996

광섬유는 코어(Core), 클레드(Clad), 그리고 1,2차 코팅(Coating)으로 구성되어 있다. 본 연구에서는 광섬유의 코팅에 생기는 결함의 유무 및 종류와 크기를 분류하는 Vision System을 구현하였다. 전처리 과정으로, CCD Camera를 이용하여 얻은 화상에 대하여 Sobel 연산자로 경계선을 추출하고, 문턱값(Threshold Value)을 적용하여 이진 화상을 만든다. 외경 정보 추출을 위하여, 투영 정보, 수리 형태학(Mathematical Morphology)적 연산을 수행하고, 결함의 종류와 크기를 효율적으로 분류하도록 Tree Classifier를 설계하였다. 실험 결과로서 각 결함 별 오차율, 전체 오차율(Total Error Rate)등을 제시하였다.

• Proceedings of the IEEK Conference
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• 2008.06a
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• pp.933-934
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• 2008

This paper describes the process of extracting defect from optical photomask images. We introduce a new method of finding photomask detects with a single optical photomask damaged image. The proposed algorithm is efficient when an original undamaged image is unavailable. The experiment showed that even a small and discontinuous photomask defect was extracted as well as continuous type of defects.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.7-8
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• 2006

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.1
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• pp.47-52
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• 2008

We present a 3-D profiler specially devised for the profile measurement of rough surfaces that are difficult to be measured with conventional non-contact interferometer. The profiler comprises multiple two-point-diffraction sources made of single-mode optical fibers. Test measurement proves that the proposed profiler is well suited for the warpage inspection of microelectronics components with rough surface, such as unpolished backsides of silicon wafers and plastic molds of integrated-circuit chip package.

• Proceedings of the KIEE Conference
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• 2004.11c
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• pp.135-137
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• 2004

In this study we'll deal with the small-sized metalized film capacitors with large capacity which head have $5mm{\times}5mm{\times}2.5mm$ dimension. The lead wire is used to weld at both sides of capacitors. At that time the position gap between the welding machine and lead wire supplier would cause the welding error. Also, during the tapping processing of metalized film capacitors, the interval error among the capacitors, the length error of lead frame attached at the capacitors, and the straightness distortion of the lead frame could happen. As mentioned, four kinds of error parameters will be measured and analyzed by using the automatic visual inspection system that is implemented with CCD camera, optical parts, background lighting, and image processing algorithms. Finally we are able to achieve success rate above 99% to detect the welding faults of capacitors in the field test.

• Journal of Institute of Control, Robotics and Systems
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• v.10 no.6
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• pp.487-493
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• 2004

In this Paper, we propose a lighting system for the stable detection of check defects of the CRT panel through the analysis of the lighting interaction between the lighting unit and the CRT panel. The check defect is very difficult to detect reliably because of its high sensitivity according to the direction of incident light. At first, we model the physical shape of check defects using SEM image. And then we apply physics based illumination model to investigate the optical characteristics of the check defect. Finally, we propose a lighting system for the stable detection of check defect. Experimental results show the feasibility of the proposed lighting system for check inspection.

• Journal of Institute of Control, Robotics and Systems
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• v.21 no.10
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• pp.982-987
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• 2015

The inspection machine in SMT (Surface Mount Technology) line detects the assembly defects such as missing, misalignment, loosing, or tombstone. We propose a new method to classify the defect types of chip components by processing the image of PCB. Two original images are obtained from horizontal lighting and vertical lighting. The image of the component is divided into two soldering regions and one packaging region. The features are extracted by appling the PCA (Principle Component Analysis) to each region. The MLP (Multilayer Perceptron) and SVM (Support Vector Machine) are then used to classify the defect types by learning. The experimental results are presented to show the usefulness of the proposed method.

• Journal of Institute of Control, Robotics and Systems
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• v.19 no.11
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• pp.974-978
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• 2013

AVI (Automatic Vision Inspection) systems automatically detect defect features and measure their sizes via camera vision. AVI systems usually report different measurements on the same defect with some variations on position or rotation mainly because different images are provided. This is caused by possible variations from the image acquisition process including optical factors, nonuniform illumination, random noises, and so on. For this reason, conventional area based defect measuring methods have problems of robustness and consistency. In this paper, we propose a new defect size measuring method to overcome this problem, utilizing volume information that is completely ignored in the area based defect measuring method. The results show that our proposed method dramatically improves the robustness and consistency of defect size measurement.