• Current Optics and Photonics
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• 제7권3호
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• pp.263-272
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• 2023

A collimator refers to an optical system that images a collimated beam at a desired point. A resolution target located at a near distance can be converted into a virtual image located at a long distance. To test the resolution for mobile cameras, a large target is placed at a long distance. If a collimator system is used, the target can be placed at a near distance. The space required for a resolution inspection can thus be drastically reduced. However, to inspect a mobile camera, the exit pupil of the collimator system and the entrance pupil of the mobile camera must match, and the stop of the collimator system must be located on the last surface. Because a collimator system cannot be symmetrical with respect to the stop, the distortion becomes extremely large, which can be corrected by combining the collimator symmetrically with respect to the object plane. A novel system was designed to inspect an optical lens on a mobile phone. After arranging the refractive power, lenses were added using the equivalent lens design method. The distortion was reduced to less than 1%. This optical system satisfies a half-field angle of 45° and an optical performance sufficient for inspection.

• 전자공학회논문지
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• 제49권11호
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• pp.74-85
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• 2012

본 논문에서는 이종 입체 카메라 시스템의 광학적 특성을 일치화하여 동일한 품질의 입체영상을 생성하는 기술을 제안한다. 이종 입체 카메라의 광학적 특성에는 크게 줌, 심도, 초점이 있으며 이들의 차이는 결과적으로 입체영상의 품질에 영향을 주어 사람의 시각 피로를 발생시키는 요인이 된다. 본 논문에서 제안하는 광학 특성 일치화 기술은 이종 카메라의 줌 영상을 일치한 후 동일 피사체에 대해 초점을 맞추고 심도를 일치화하는 과정으로 이루어진다. 이를 위하여 이종 입체 카메라의 줌 영상의 비교 알고리즘을 통하여 줌 렌즈에 대한 룩업테이블(LUT)을 작성하였다. 그리고 입체 영상의 에지(edge)에서 초점 정보를 추출하여 심도를 일치화하였다. 광학적 특성 일치화 실험을 위하여 직교방식의 리그를 제작하고 서로 다른 사양의 HD급 카메라를 이용하여 입체 카메라 장치를 구성하였다. 줌 일치화 및 심도 일치화에 대한 실험 결과로 시각 피로를 줄일 수 있는 입체 영상 생성이 가능함을 보였다.

• 한국항공우주학회지
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• 제32권10호
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• pp.142-146
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• 2004

인공위성용 지구관측 카메라나 천문관측 망원경에는 무게와 부피의 제약 때문에 Cassegrain 방식 망원경이 많이 쓰인다. 이와 같은 위성용 광학계의 성공적인 임무 수행을 위해서는 광학계의 정밀 정렬이 필수적이다. 본 논문에서는 인공위생용 지구관측 카메라인 MAC (Medium-sized Aperture Camera)의 조립 과정에 적용된 컴퓨터를 이용한 광학정렬 방법의 모사와 정렬실험 결과를 정리한다.

• 전기학회논문지
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• 제66권9호
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• pp.1416-1423
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• 2017

Lane detection technology is one of the most important issues on car safety and self-driving capability of autonomous vehicle. This paper introduces an accurate lane detection scheme based on OCC(Optical Camera Communication) for moving vehicles. For lane detection of moving vehicles, the streetlights and the front camera of the vehicle were used for a transmitter and a receiver, respectively. Based on the angle information of multiple streetlights in a captured image, the distance from sidewalk can be calculated using non-linear regression analysis. Simulation results show that the proposed scheme shows robust performance of accurate lane detection.

• 전기학회논문지
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• 제67권7호
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• pp.878-883
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• 2018

This paper proposes a method for transmitting instruction between vehicles in a moving situation using RC Car having camera. Information of preceding RC Car was transmitted by LED using Optical Camera Communication(OCC). Rear RC Car follows the preceding one by analyzing transmitted OCC data based on image processing. Through this procedure, the information reception ratio according to the distance change of two RC Cars is confirmed. Through experiments, we showed that our proposed scheme enables the possibility of vehicle platooning.

• 한국컴퓨터정보학회논문지
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• 제21권12호
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• pp.19-26
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• 2016

In this paper, we propose an efficient design method for a thermal camera with continuous zoom based on the research and manufacturing experience of the thermal camera. In addition, it is divided into system design method, optical design method, mechanical design method, and electronic design method. First, we propose an effective NUC compensation method and a lens-specific sensitivity design method in terms of system. Second, we propose a zoom trajectory design method considering the temperature effect on the optical aspect. Third, it suggests the minimization of optical axis shaking between magnification conversion in terms of mechanism. Finally, we propose a lens-specific temperature compensation method and a speed conversion algorithm according to the zoom interval as an electronic aspect.

• 정보저장시스템학회논문집
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• 제7권2호
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• pp.70-74
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• 2011

The mobile camera module is a device to be inserted in the digital device for camera feature. The mobile camera module is being shaken by vibrations such as handshake during the exposure time. The clarity is compromised by these vibrations, thus the vibration is considered as an external disturbance. Moreover the use of mobile camera module has been being expanded for automotive vibration should be considered. These external disturbances can cause image blurring, thus optical image stabilization should be applied for image compensation. The compensator is fulfilled mechanically by movable lens group or image sensor that adjusts the optical path to the camera movement. Open loop control is useful for well-defined systems like compliant mechanism. Notch filter and lead compensator are designed and applied to improve the stability and bandwidth. The final level of image compensating is confirmed by image processing with MATLAB and CODE V to verify the better performance.

• 한국광학회지
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• 제17권2호
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• pp.113-119
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• 2006

망막검사를 위한 검안경용 망막 카메라를 개발하기 위한 광학계 설계를 연구하였다. 이에 앞서 사람의 눈에 대한 광학계 제원은 김상기와 박성찬이 발표한 정밀모형안을 채택하였다. 이를 토대로 하여 광학계를 4개의 렌즈 군으로 구성하였고 제 1군으로 모든 시야각에 대한 광을 중심으로 모았다가 제2, 제3, 제4군에 의해 결상하도록 하였다. 결상된 망막의 상은 CCD 광검출기에 의해 모니터로 전시한다. 제 1군을 단일 렌즈로 하고 나머지 광학계를 triplet로 하여 최적화를 통해 설계하였다. 광선수차, spot diagram, 회절을 고려한 point spread function 및 MTF를 계산하여 분석한 결과, 좋은 성능을 가진 광학계 설계가 가능하였다. 본 연구 결과에서 얻은 광학계로서 양질의 망막 카메라를 개발할 순 있을 것으로 믿는다.

• Journal of the Optical Society of Korea
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• 제10권3호
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• pp.105-111
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• 2006

A novel image quality evaluation method, which is based on combination of the rigorous grating diffraction theory and the ray-optic method, is proposed. It is applied for design optimization and, tolerance analysis of optical imaging systems implementing diffractive optical elements (DOE). The evaluation method can predict the quality and resolution of the image on the image sensor plane through the optical imaging system. Especially, we can simulate the effect of diffraction efficiencies of DOE in the camera lenses module, which is very effective for predicting different color sense and MTF performance. Using this method, we can effectively determine the fabrication tolerances of diffractive and refractive optical elements such as the variations' in profile thickness, and the shoulder of the DOE, as well as conventional parameters such as decenter and tilt in optical-surface alignments. A DOE-based 2M-resolution camera lens module designed by the optimization process based on the proposed image quality evaluation method shows ${\sim}15%$ MTF improvement compared with a design without such an optimization.

• 제어로봇시스템학회논문지
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• 제18권2호
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• pp.110-117
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• 2012

This paper describes a new design of optical flow estimation system with three cameras. Optical flow provides useful information of camera movement; however a unique solution is not usually available for unknowns including the depth information. A camera and two tilted cameras are used to have different view of angle and direction of movement to the camera axis. Geometric analysis is performed for cases of several independent movements. The ideas of taking advantage of the extra information for robot navigation are discussed with experimental results.