• 한국광학회지
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• 제27권1호
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• pp.25-31
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• 2016

이 전에 발표한 멀티스케일 기가픽셀카메라에 대한 두 편의 이론과 실험연구를 바탕으로 본 논문에서는 최종적이고 종합적인 28개의 구조방정식들을 도출하였다. 본 논문의 결과 식들을 활용하면 어레이카메라 방식으로 구성되는 멀티스케일 기가픽셀카메라의 광학구조에 대한 통찰적인 이해가 가능하게 될 것이고 완전하고 신속하게 다양한 구조인자 값들을 손쉽게 획득 할 수 있을 것이다.

• 한국광학회지
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• 제11권1호
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• pp.6-12
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• 2000

위성에 탑재된 지구관측용 카메라는, 지상의 망원경과 같은 원리로, 우주상공에서 지표면 관측을 자동적으로 수행하고 관측정보를 지상으로 전달해 주는 장치다. 이용 목적에 따라 카메라의 해상도 또는 분해능, 관측대역, 관측폭, 위성의 궤도 등의 규격이 결정된다. 고해상도는 카메라 관련 제반 기술 및 경험이 부족한 국내의 여건에 적합한 소형 위성용 고해상도 카메라의 규격을 제시하며 이에 따른 광학 설계와 제작, 조립 및 측정오차를 제시한다.

• 한국통신학회논문지
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• 제42권1호
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• pp.8-13
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• 2017

Compare with other communication system based RF technology, Optical Camera Communication (OCC) has limitation on data rate due to the low frame rate of camera. The limitation on data rate can be solved with multiple-input and multiple-output (MIMO) technology; and it is the final target of all researches on OCC. The MIMO topology can be implemented easily without breaking out the architecture of image sensor. For image sensor classification, there are two architectures have been developed: rolling shutter and global shutter. The operation of two techniques is different so the performance is also different. In this paper we analyze and evaluate the performance of the MIMO architecture for OCC.

• Current Optics and Photonics
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• 제1권5호
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• pp.468-473
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• 2017

We determined the feasibility of a fishing camera system using an optical fiber as the fishing line by testing a power-over-fiber (POF) module and multimode optical fiber. Operation of the remote camera module (RCM) without the battery was preferred because the removal of the charging or battery replacement section enabled a waterproof single-body type design. The average efficiency of the photovoltaic power converter (PPC) in the tested POF module was 32.6% at 820 nm, and thus, a high-power laser of at least 1.27 W was required for operating the developed RCM with an electrical dissipation of 413 mW. Because the optical fiber was wound on a fishing reel, composite loss composed of bending and tensile loss occurred. To mitigate the composite loss, we employed a simple holder that showed an improvement in the composite loss of 0.38 dB to 0.8 dB, which was considerably better than the losses without the holder.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1998년도 제13차 학술회의논문집
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• pp.232-237
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• 1998

This paper describes a new method for estimating time-to-collision which exhibits high tolerance to noise contained in camera images. Time to collision (TTC) is one of the most important parameters available from a camera attached to a mobile machine. TTC indirectly stands far the translation speed of the camera and is usually calculated either from successive images or optical flow by using intimate relationship between TTC and flow divergence. In most cases, however, it is not easy to get accurate optical flow, which makes it difficult to calculate TTC. In this study it is proved that if the target has a smooth surface, the average of divergence over any point-symmetric region on the image is equal to the divergence of the center of the region. It means that required divergence can be calculated by integrating optical flow vectors over a symmetric region. It is expected that in the process of the integration, accidental noise is canceled if they are independent of optical flow and the motion of the camera. Experimental results show that TTC can be estimated regardless of the surface condition. It is also shown that influence of noise is eliminated as the area of integration increases.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
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• pp.1836-1839
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• 1997

This paper presents machine vision technique with a camera modeling that accounts for major sources of camera distortion, namely, radial, decentering, and thin prism distortion. Radial distortion causes an inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to various degrees of decentering, that is, the optical centers of lens elements are not strictly collinear. It is our purpose to develop the vision system for the pattern recognition and the automatic test of parts and to apply the line of manufacturing.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.179-185
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• 1997

This paper presents machine vision technique with a camera modeling that accounts for major sources of camera distortion, namely,radial, decentering, and thin prism distortion. Radial distortion causes an inward or outward displacement of a given image point from its ideal location. Actual optical systems are subject to varios degrees of decentering,that is,the optical centers of lens elements are not strictly collinear. Thin prism distortion arises form imperfection in lens design and manufacturing as well as camera assembly. It is our purpose to develop the vision system for the pattern recognition and the automatic test of and to apply the line of part manufacturing.

• International journal of advanced smart convergence
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• 제4권2호
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• pp.94-102
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• 2015

Optical camera communication (OCC) is an extension of Visible Light Communication. Different from traditional visible light communication, optical camera communications is an almost no additional cost technology by taking the advantage of build-in camera in devices. It was became a candidate for communication protocol for IoT. Camera module can be easy attached to IoT device, because it is small and flexible. Furthermore almost smartphone equip one or two camera for both back and font side with high quality and resolution. It can be utilized for receiving the data from LED or positioning. Actually, OCC combines illumination and communication. It can supply communication for special areas or environment where do not allow Radio frequency such as hospital, airplane etc. There are many concept and experiment be proposed. In this paper we proposed utilizing Android smart-phone camera for receiver and introduce new approach in modulation scheme for LED at transmitter. It also show how Manchester coding can be used encode bits while at the same time being successfully decoded by Android smart-phone camera. We introduce new data frame format for easy decoded and can be achieve high bit rate. This format can be easy to adapt to performance limit of Android operator or embedded system.

• 한국광학회:학술대회논문집
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• 한국광학회 1990년도 제5회 파동 및 레이저 학술발표회 5th Conference on Waves and lasers 논문집 - 한국광학회
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• pp.82-86
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• 1990

A camera type optical bench system equipped with a lens collimator and an image analyzer is fabricated to measure the equivalent focal length and distortion of lenses. This system is automatized by the computer which controls stepping motors. A nodal slide optical bench system equipped with an off axis reflective collimator is fabricated and improved by using rotating arms and air bearing system. distortion measurement on a wide angle lens using the camera method and the nodal slide method is reported. Defocusing error in the distortion measurement with the nodal slide optical bench is analyzed and improved by iteration method to search the correct image point.

• 한국광학회지
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• 제20권3호
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• pp.148-155
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• 2009

본 연구에서는 광학계의 굴절률, 중심두께 및 곡률반경에 대한 설계변수가 온도변화에 따라 1차 특성 및 결상성능에 어떠한 영향을 미치는지 분석하고, 이로부터 온도보정 설계를 실시하였다. 광학설계 변수들을 각각의 사용온도에 해당되는 값으로 변경한 후, 기존의 coupling 및 ruler 설계 개념을 폰 카메라용 렌즈설계에 적용하여 온도보정을 고려한 설계방법을 제시하였다. 본 연구에서 제시한 온도보정 설계개념을 4매 구성의 1/3.2" 5M 렌즈계에 최초로 적용하여 최적 설계한 결과, 폰 카메라용 렌즈에 대한 일반사양을 만족시키는 동시에 사용온도 $-10^{\circ}C{\sim}+60^{\circ}C$에서의 후초점거리 변화량에 대한 요구사양(${\Delta}BFL{\leq}10{\mu}m$)도 만족시켰다. 또한 최적 설계된 렌즈계의 전장(TTL)은 5.5 mm로 매우 컴팩트한 구성이다. 따라서 본 연구의 결과는 휴대폰 카메라 및 감시 카메라용 광학계 개발에 활용이 가능할 것으로 기대된다.