• 한국정밀공학회지
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• 제19권1호
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• pp.172-179
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• 2002

In a robot/vision system, the vision sensor, typically a CCD array sensor, is mounted on the robot hand. The problem of determining the relationship between the camera frame and the robot hand frame is refered to as the hand-eye calibration. In the literature, various methods have been suggested to calibrate camera and for sensor registration. Recently, one-step approach which combines camera calibration and sensor registration is suggested by Horaud & Dornaika. In this approach, camera extrinsic parameters are not need to be determined at all configurations of robot. In this paper, by modifying the camera model and including the lens distortion effect in the perspective transformation matrix, a new one-step approach is proposed in the hand-eye calibration.

• 한국광학회지
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• 제31권1호
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• pp.26-30
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• 2020

로봇 카메라를 이해하고 제작하기 위해서는 로봇 카메라의 회전이나 공간 이동에 의해 발생하는 인접 이미지 간의 영상 왜곡에 대한 이해가 우선적으로 진행되어야 한다. 본 논문에서는 영상 왜곡에 관한 수학적인 해석과 이 수학적인 해석을 렌즈 시스템과 연결하여 일반화하고 결국 로봇 카메라에서 일어나는 영상의 왜곡인 parallax 오차에 대한 유용한 해석 방정식을 얻었다. 이 방정식으로부터 로봇 카메라의 구조설계가 가능하게 되고 한 예로서 기존 구글의 ART 로봇 카메라에 대한 분석과 이해가 확장될 수 있었다.

• 반도체디스플레이기술학회지
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• 제5권1호
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• pp.1-4
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• 2006

Recently, Ball Grid Arrays(BGAs) are getting used more frequently for a package type. The connectors on a BGA consist of a large number of small solder balls in a grid shape on its bottom side. However, since balls of BGAs mounted on PCBs are not visible, inspection before mounting them is indispensable. High speed non-contact 3D measurement technologies are necessary far real-time measurement of ball height, the most important inspection item. In this paper, an accurate 3D data acquisition system for BGAs is proposed that can acquire 3D profile at high speed using a 3D smart camera and laser slit ray projection. Some clipping and morphological filtering operations are employed to remove spiky error data, which occur due to reflections from some ball area to camera direction.

• 한국정보처리학회:학술대회논문집
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• 한국정보처리학회 2012년도 춘계학술발표대회
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• pp.352-354
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• 2012

본 논문에서는 웹캠 카메라 어레이(camera array)로 얻은 여러 장의 이미지를 빠른 속도로 봉합(stitching)하여 고해상도 이미지를 얻기 위해 그래픽스 하드웨어를 이용하는 병렬 알고리즘을 제시한다. 고정된 레이아웃의 카메라 어레이를 이용하여 평면 혹은 원경을 촬영하는 경우, 기존에 널리 쓰이던 평면 사영 이미지 봉합(planar projective image stitching)과 선형 혼합(linear blending)을 통해 만족스런 결과를 얻을 수 있다. 본 논문에서는 이러한 연산을 그래픽스 하드웨어에서 병렬처리 함으로써 추후 실시간 고해상도 동영상 스트리밍 이미지 병합에 활용할 수 있을 정도로 빠른 속도로 처리하는 방법을 제시한다.

• 한국기계가공학회지
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• 제8권3호
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• pp.46-53
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• 2009

To find the working condition is one of the important factors in precision machining. In this study, we analyzed maximum working temperature by infra-red camera and surface roughness in side wall end milling using design of experiment (DOE): RSM(response surface methodology), ANOM(analysis of means) and ANOVA(analysis of variance) by table of orthogonal array. ANOM and ANOVA are well adapted to select sensitivity of design variables for maximum working temperature and surface roughness. The effective design variables and their levels should be determined using ANOM, ANOVA. RSM is presented 2nd order approximation polynomial of maximum working temperature and surface roughness is composed with design variables. Therefore, it is expected that the proposed procedure using design of experiment : table of orthogonal array, ANOM, ANOVA and RSM can be easily utilized to solve the problem of working condition.

• 한국통신학회논문지
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• 제38C권9호
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• pp.781-786
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• 2013

Multiplexing information over parallel data channels based on RF MIMO concept is possible to achieve considerable data rates over large transmission ranges with just a single transmitting element. Visual multiplexing MIMO techniques will send independent streams of bits using the multiple elements of the light transmitter array and recording over a group of camera pixels can further enhance the data rates. The proposed system is a combination of the reliance on computer vision algorithms for tracking and OOK cell frame modulation. LED array are controlled to transmit message in the form of digital information using ON-OFF signaling with ON-OFF pulses (ON = bit 1, OFF = bit 0). A camera captures image frames of the array which are then individually processed and sequentially decoded to retrieve data. To demodulated data transmission, a motion tracking algorithm is implemented in OpenCV (Open source Computer Vision library) to classify the transmission pattern. One of the most advantages of proposed architecture is Computer Vision (CV) based image analysis techniques which can be used to spatially separate signals and remove interferences from ambient light. It will be the future challenges and opportunities for mobile communication networking research.

• 센서학회지
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• 제19권3호
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• pp.246-257
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• 2010

Autonomous guided robot navigation which consists of following unknown paths and avoiding unknown obstacles has been a fundamental technique for unmanned robots in outdoor environments. The unknown path following requires techniques such as path recognition, path planning, and robot pose estimation. In this paper, we propose a novel sensor fusion system for autonomous guided robot navigation in outdoor environments. The proposed system consists of three monocular cameras and an array of nine infrared range sensors. The two cameras equipped on the robot's right and left sides are used to recognize unknown paths and estimate relative robot pose on these paths through bayesian sensor fusion method, and the other camera equipped at the front of the robot is used to recognize abrupt curves and unknown obstacles. The infrared range sensor array is used to improve the robustness of obstacle avoidance. The forward camera and the infrared range sensor array are fused through rule-based method for obstacle avoidance. Experiments in outdoor environments show the mobile robot with the proposed sensor fusion system performed successfully real-time autonomous guided navigation.

• Current Optics and Photonics
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• 제5권5호
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• pp.524-531
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• 2021

In an integral-imaging microscopy (IIM) system, a microlens array (MLA) is the primary optical element; however, surface errors impede the resolution of a raw image's details. Calibration is a major concern with regard to incorrect projection of the light rays. A ray-tracing-based calibration method for an IIM camera is proposed, to address four errors: MLA decentering, rotational, translational, and subimage-scaling errors. All of these parameters are evaluated using the reference image obtained from the ray-traced white image. The areas and center points of the microlens are estimated using an "8-connected" and a "center-of-gravity" method respectively. The proposed approach significantly improves the rectified-image quality and nonlinear image brightness for an IIM system. Numerical and optical experiments on multiple real objects demonstrate the robustness and effectiveness of our proposed method, which achieves on average a 35% improvement in brightness for an IIM raw image.

• 한국산업정보학회논문지
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• 제18권5호
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• pp.45-50
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• 2013

최근 시장이 확대되고 있는 SMART TV에는 다양한 기능을 위하여 내장형 카메라가 들어가게 된다. 하지만, 이로 인한 불량 또한 발생하게 되며, 특히 TV power up sequence 문제로 인한 내장형 카메라의 화면 무감 불량현상은 기존 검사장비에서 검출되기 힘든 특징을 가지고 있다. 이를 위해 오디오 쪽 컨트롤 신호를 재현할 수 있는 새로운 검사장비가 필요하지만, 시간과 많은 비용이 소요되며, 생산에 큰 영향을 준다. 본 논문에서는 이와 같은 문제점을 해결하고자 FPGA (Field Programmable Gate Array)를 활용한 불량 검출 장비를 개발하여 문제점을 빠르고 정확하게 검출하는 방법을 제시한다. 이를 통해 새로운 장비를 대체하는 비용 절감 효과와 기존 검출 테스트 시간을 약 20여초에서 10초미만으로 크게 단축시킴으로써 개발기간의 최소화 및 공정에 적용을 통한 불량률 감소를 이룰 수 있다.

• 천문학회보
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• 제38권2호
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• pp.85.2-85.2
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• 2013

We developed autoguiding system for IGRINS (Immersion Grating Infrared Spectrograph) which is a high resolution near-IR spectrograph. This instrument will be attached on the 2.7m telescope at the McDonald observatory in 2013 November. IGRINS consists of three near-Infrared detector modules, i. e., H and K band spectrograph modules and a K band slit camera module, within which we are using the slit camera for autoguiding of the telescope. Comparing to typical optical CCDs, however, the infrared array shows non-uniform responses, higher noises, and many bad pixels. In this poster, we present methods to improve center finding functions and algorithms for the infrared array and the simulator test results of the IGRINS Slit-Camera Package.