• 전기전자학회논문지
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• 제18권2호
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• pp.234-239
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• 2014

This paper proposes a new automatic detection method to inspect mura defects on display film surface using morphological image processing and labeling. This automatic detection method for mura defects on display films comprises 3 phases of preprocessing with morphological image processing, Gabor filtering, and labeling. Since distorted results could be obtained with the presence of non-uniform illumination, preprocessing step reduces illumination components using morphological image processing. In Gabor filtering, mura images are created with binary coded mura components using Gabor filters. Subsequently, labeling is a final phase of finding the mura defect area using the difference between large mura defects and values in the periphery. To evaluate the accuracy of the proposed detection method, detection rate was assessed by applying the method in 200 display film samples. As a result, the detection rate was high at about 95.5%. Moreover, the study was able to acquire reliable results using the Semu index for luminance mura in image quality inspection.

• 한국정보전자통신기술학회논문지
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• 제11권5호
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• pp.615-622
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• 2018

최근 가시광원을 사용하는 카메라 통신 기술의 발전과 더불어 디스플레이를 통해 가시광 데이터를 표출하고 이를 인식하는 기술에 대한 수요가 증가하고 있다. 기존의 디스플레이 기반 CamCom 기법은 사용자가 설정한 RoI 영역 기반의 2차원 컬러코드를 인식하는 방식을 사용하였으나, 이는 보행 상황 등 수신위치가 변동되는 상황에 적합하지 않은 단점이 존재한다. 이에 본 논문에서는 카메라 통신에서 자동 RoI 설정을 위해 적용될 수 있는 Lambertian 색상 분할과 Canny 엣지 검출이 결합된 알고리즘 기반의 자동 디스플레이 검출 기법에 대하여 제안하였다. 기존 디스플레이 검출 기법은 디스플레이에서 표출되고 있는 콘텐츠의 변화가 발생하면 검출율이 현저히 감소하는 문제점이 존재하며, 본 논문에서는 이를 해결하기 위하여 lambertian 색상 분할 및 canny 엣지 검출을 결합한 알고리즘 적용을 통헤 자동으로 디스플레이를 검출 할 수 있는 기법을 제안하였다. 본 연구에서는 디스플레이 엣지 인식을 위해 사용되는 다양한 알고리즘을 분석하고 변화하는 컬러코드 콘텐츠 인식시 성능을 측정하였으며, 제안한 저속 카메라 통신용 자동 디스플레이 검출을 위한 lambertian 색상 분할 및 Canny Edge Detection 알고리즘을 적용한 실험 결과 약 96%의 검출율을 달성함을 확인하였다.

• 반도체디스플레이기술학회지
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• 제21권4호
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• pp.77-80
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• 2022

Automatic Vision Inspection (AVI) systems automatically detect defect features and measure their sizes via camera vision. It has been populated because of the accuracy and consistency in terms of QC (Quality Control) of inspection processes. Also, it is important to predict the performance of an AVI to meet customer's specification in advance. AVI are usually suffered from false negative and positives. It can be overcome by providing extra information such as 3D depth information. Stereo vision processing has been popular for depth extraction of the 3D images from 2D images. However, stereo vision methods usually take long time to process. In this paper, retro optical system using reflectors is proposed and experimented to overcome the problem. The optical system extracts the depth without special SW processes. The vision sensor and optical components such as illumination and depth detecting module are integrated as a unit. The depth information can be extracted on real-time basis and utilized and can improve the performance of an AVI system.

• Industrial Engineering and Management Systems
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• 제8권3호
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• pp.148-154
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• 2009

In recent days, large-sized flat-panel display (FPD) has been increasingly applied to computer monitors and TVs. Mura defects, appearing as low contrast or non-uniform brightness region, sometimes occur in manufacturing of the Thin-Film Transistor Liquid-Crystal Displays (TFT-LCD). Implementation of automatic Mura inspection methods is necessary for TFT-LCD production. Various existing Mura detection methods based on regression diagnostics, surface fitting and data transformation have been presented with good performance. This paper proposes an efficient Mura detection method that is based on a regression diagnostics using studentized residuals for automatic Mura inspection of FPD. The input image is estimated by a linear model and then the studentized residuals are calculated for filtering Mura regions. After image dilation, the proposed threshold is determined for detecting the non-uniform brightness region in TFT-LCD by means of monitoring the every pixel in the image. The experimental results obtained from several test images are used to illustrate the effectiveness and efficiency of the proposed method for Mura detection.

• 한국정밀공학회지
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• 제24권4호
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• pp.15-20
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• 2007

• 전기학회논문지
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• 제57권7호
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• pp.1295-1297
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• 2008

Large-sized flat-panel displays are widely used for PC monitors and TV displays. In this paper, frequency domain pre-filter algorithms are presented for detection of defects in large-sized Thin Film Transistor-Liquid Crystal Display(TFT-LCD) panel surfaces. Frequency analysis with 1-D, 2-D FFT methods for extract the periodic patterns of lattice structures in TFT-LCD is performed. To remove this patterns, frequency domain band-stop filters were used for eliminating specific frequency components. In order to acquire only defected images, 2-D inverse FFT methods to inverse transform of frequency domain images were used.

• 반도체디스플레이기술학회지
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• 제19권2호
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• pp.11-15
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• 2020

In a typical initial setup of a PCB component inspection system, operators should manually input various information such as category, position, and inspection area for each component to be inspected, thus causing much inconvenience and longer setup time. Although there are many deep learning based object detectors, RetinaNet is regarded as one of best object detectors currently available. In this paper, a method using an extended RetinaNet is proposed that automatically detects its component category and position for each component mounted on PCBs from a high-resolution color input image. We extended the basic RetinaNet feature pyramid network by adding a feature pyramid layer having higher spatial resolution to the basic feature pyramid. It was demonstrated by experiments that the extended RetinaNet can detect successfully very small components that could be missed by the basic RetinaNet. Using the proposed method could enable automatic generation of inspection areas, thus considerably reducing the setup time of PCB component inspection systems.

• 반도체디스플레이기술학회지
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• 제16권4호
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• pp.79-85
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• 2017

Understanding of human emotion has a high importance in interaction between human and machine communications systems. The most expressive and valuable way to extract and recognize the human's emotion is by facial expression analysis. This paper presents and implements an automatic extraction and recognition scheme of facial expression and emotion through still image. This method has three main steps to recognize the facial emotion: (1) Detection of facial areas with skin-color method and feature maps, (2) Creation of the Bezier curve on eyemap and mouthmap, and (3) Classification and distinguish the emotion of characteristic with Hausdorff distance. To estimate the performance of the implemented system, we evaluate a success-ratio with emotional face image database, which is commonly used in the field of facial analysis. The experimental result shows average 76.1% of success to classify and distinguish the facial expression and emotion.

• 한국정보전자통신기술학회논문지
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• 제4권2호
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• pp.96-102
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• 2011

본 연구에서는 현대인의 대표적 발 질환 중 하나인 무지외반증의 증상정도 자동 분류 알고리즘 개발에 대한 연구를 수행하였다. 무지외반증의 치료 및 수술을 위한 기존 아날로그적 진단법이 아닌 디지털 영상처리기법을 사용함으로써 효과적인 자동화 진단법을 제시하였다. 이를 위해 본 연구에서는 각각 정상인과 무지외반증 환자의 X-Ray 영상을 이용하였다. 우선 정상인의 X-Ray 영상에 정상 각도를 오버랩과 애드 방법을 통하여 기준각도를 표시한 후, 윤곽선 검출 알고리즘인 로버츠 필터와 세선화 작업을 거쳐 통칭 정상인 기준 영상을 만들었다. 그리고 진단할 환자의 X-Ray 영상에 윤곽선 검출 알고리즘인 소벨 필터를 거쳐 환자 영상을 만들어 앞서 언급한 정상인 기준 영상과 오버랩과 애드 방법을 통하여 디스플레이 출력 영상을 구현하였다. 디스플레이 출력 영상을 이용하여 무지외반증 진단 각도를 측정하여 화면에 디스플레이 함으로써 기존의 아날로그적 진단법에서 탈피한 디지털적 영상처리 진단법을 제시하였으며 그 실용성과 타 정형외적 질환의 응용성을 확인하였다.

• 반도체디스플레이기술학회지
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• 제7권3호
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• pp.11-16
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• 2008

The authors investigated an overhead shuttle (OHS) system for automatic transferring the liquid crystal display (LCD) panels. The constructed tracks of OHS system include the linear and curve regions and have been installed on the ceiling to transfer the cassette of LCD glass along the closed-loop and open-loop tracks. In this study, the OHS system was implemented by a proposed linear motor to solve encoder installation and the system cost problems of the long distance transfer system. In addition, we utilized a new algorithm of the position detection and a new control algorithm for driving linear motor. The newly developed control algorithm was demonstrated from both a computer simulation and an experimentation, indicating that the highly reliable and speedy transfer system can enhance the LCD panel productivity of commercial OHS system.