• Journal of Institute of Control, Robotics and Systems
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• v.13 no.3
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• pp.224-229
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• 2007

This paper presents a camera calibration method using several images for three dimensional measurement applications such as stereo systems, mobile robots, and visual inspection systems in factories. Conventional calibration methods that use single image suffer from errors related to reference point extraction in image, lens distortion, and numerical analysis of nonlinear optimization. The camera parameter values obtained from images of same camera is not same even though we use same calibration method. The camera parameters that are obtained from several images of different view for a calibration target is usaully not same with large error values and we can not assume a special probabilistic distribution when we estimate the parameter values. In this paper, the median value of camera parameters from several images is used to improve estimation of the camera values in an iterative step with nonlinear optimization. The proposed method is proved by experiments using real images.

• Proceedings of the Optical Society of Korea Conference
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• 2000.02a
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• pp.218-219
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• 2000

정보화 사회의 발전과 더불어 디스플레이는 CRT의 고성능화와 병행해 각종 평판 디스플레이의 전개와 실용화가 진행되어 왔다. TV용은 CRT (cathod ray tube)방식이 시장의 90% 이상을 차지하고 있으며, 앞으로도 연간 약 3%의 성장이 예상된다. CRT는 많은 공간 소비와 높은 소비전력 유해파 등으로 인하여 가정용 TV의 경우 PDP가 컴퓨터 모니터는 LCD방식이 디스플레이 시장의 주역을 담당하고 있으며, 그 성능, 비용, 용도에 따라 나뉘어 빠른 비율로 성정해 갈 것으로 예상된다. 이러한 여러 가지 평판 디스플레이들은 특성에 따라 EL과 FED는 10인치 이하의 소형 디스플레이에 주로 사용되어 지며, LCD는 10인치 이하에서부터 30인치까지의 소·중형, CRT는 10인치 이상 40인치 이하의 중·대형에 사용되어 지고, PDP는 30인치 이상의 대형 디스플레이에 사용된다. 대형 PDP나 LCD는 휘도를 높이고 양질의 영상 표현을 위해서는 cell-gap의 균일성이 요구되어 진다. cell-gap의 측정은 제품이 거의 완성 단계 있을 때 이루어져야 함으로 비접촉식이 필연적이며, 실시간 적이어야만 가능하다. (중략)

• Proceedings of the Optical Society of Korea Conference
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• 2009.10a
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• pp.288-289
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• 2009

We report an optimum fabrication condition for formation of concave lens shaped core cross-section of silica single-mode fibers with hydrofluoric (HF) acid solutions and arc discharge. A desired depth of curved cross-section of the silica fiber core and its surface smoothness were obtained with optimized concentration of the HF solution, etching time, and arc discharge condition.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.137-140
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• 2008

Recently many areas require wide field of view images. Such as surveillance, virtual reality, navigation and 3D scene reconstruction. Conventional camera systems have a limited filed of view and provide partial information about the scene. however, omni directional vision system can overcome these disadvantages. Acquiring 360 degree panorama images requires expensive omni camera lens. In this study, 360 degree panorama image was tested using a low cost optical reflector which captures 360 degree panoramic views with single shot. This 360 degree panorama image system can be used with detailed positional information from GPS/INS. Through this study result, we show 360 degree panorama image is very effective tool for mobile monitoring system.

• Journal of the Korean earth science society
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• v.38 no.5
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• pp.323-332
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• 2017

The Digital Single Lens Reflex (DSLR) camera combined with a small aperture telescope is an efficient equipment for an astronomy-related lab exercise. This paper compares the different photometry softwares to provide insights on using the GUI-based photometry tool to the conventional command-line based photometry tool. The magnitude of the same point source measured within the aperture is consistent regardless of the software used although the background estimation, partial pixel treatment, and error estimation are slightly different. In a crowded field image where the aperture photometry is less reliable, the aperture photometry with varying aperture size is useful to see the qualitative trend for the magnitude. Due to the variation in ISO settings and the color dependence on the RGB Bayer system, an initial uncertainty of ~0.15mag is expected to be embedded in the magnitude derived from the DSLR images.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.503-506
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• 2008

The integral imaging is a promising 3D display technology since it is able to deliver continuous viewing points, full parallax, and full color view to the observers in space. In this paper, we propose a novel interactive 3D integral imaging system using a single camera. The user interface is implemented by adding a camera in the conventional integral imaging system. To show the possibility of the proposed system, we implement the optical setup and present the preliminary results

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.128.1-128.1
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• 2014

잠자리, 벌 등 곤충과 새우, 가재 등 갑각류를 포함하는 절지동물류에서 발견되는 겹눈(compound eye)구조는 볼록한 형태이기 때문에 일반 단일렌즈(single lens)형 눈에 비해 매우 넓은 시야각을 가지며, 깊은 심도를 갖는 특징이 있다. 기존 카메라가 갖기 어려운 겹눈의 독특한 장점으로 인해, 곤충의 눈을 모방하는 연구는 많은 사람들의 주목을 받고 있다. 겹눈구조는 일반적으로 수백에서 수만개의 홑눈(ommatidium)이 모여 다발을 이루고 있으며, 각 홑눈은 겉에서부터 마이크로렌즈 형태의 각막, 수정추, 감간(rhabdom)형태로 이루어져 있다. 따라서 이러한 겹눈구조를 모방하기 위해서는 인공홑눈을 제작하고 이를 반구형으로 배열하는 것이 필수적이다. 그러나 실리콘 반도체를 기반으로 하는 이미지 센서는 딱딱하고 편평하여 굴곡진 형태로 배열이 어렵기 때문에 곤충눈을 모방한 형태의 구조물은 몇몇 연구그룹에서 개발된 사례가 있으나, 이미징이 가능한 곤충눈 시스템의 개발은 보고된 바가 없었다. 본 발표에서는 최근에 연구가 진행되고 있는 플렉서블 전자소자에 기반한 곤충눈을 모방한 이미징 시스템에 대해서 다루고자 한다.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.35-38
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• 2002

Ferrite thin film with glass substrate was prepared by ferrite plating method in order to make sunglass which cut off ultraviolet and electromagnetic field. It has single phase of polycrystalline spinel structure and has gloss like as mirror and has hardness without scratch by scraping with nail. The transmittance of ferrite thin film is lowered near 400nm manifestly, which shows that the ferrite thin film was cut off ultraviolet successfully. Therefore, the sunglass with ferrite plating is use of cut of ultraviolet and electromagnetic field.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.77-77
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• 2000

The shape of small or curved object is usually reconstructed using a single camera by moving its lens position to find a sequence of the focused images. Most conventional methods have used a window with fixed shape to test the focus measure, which resulted in a deterioration of accuracy. To solve this problem, this paper proposes a new approach of using a shape adaptive window. It estimates the shape of the object at every step and applies the same shape of window to calculate the focus measure. Focus measure is based on the variance of the pixels inside the window. This paper includes the experimental results.

• Journal of KSNVE
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• v.9 no.5
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• pp.984-990
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• 1999

This paper presents the geometrical methodology to decouple the vibration modes of an elastically supported single rigid body in three-dimensional space. It is shown that the vibration modes can be decoupled by placing the center of elasticity at suitable locations and thereby yielding the plane(s) of symmetry for the given stiffness matrix. The developed methodology has been applied to the actuator supported by the 4-wire suspensions in optical discs, which has one plane of symmetry. For this numerical example, the axes of vibrations have been computed and illustrated with the natural frequencies. The forced response at the objective lens is represented and its geometrical interpretation has been explained as the mutual moment between the axis of vibration and the applied wrench times the line coordinates of the axis of vibration.