• 한국정보디스플레이학회:학술대회논문집
• /
• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
• /
• pp.463-467
• /
• 2003

Optical architecture and experimental results on low cost multiview autostereoscopic projection display are presented. The display, containing only one high resolution projection panel and only one projection lens is capable of displaying multiview autostereoscopic images. Key components, applied in the display are segmented mirror for splitting the projection beam and one-dimensional diffuser with slanted axis of diffusion for viewing zone formation. Image distortions, inherent in the display have been compensated with opposite sign pre-distortion of projected perspective images.

• 한국광학회지
• /
• 제19권2호
• /
• pp.144-149
• /
• 2008

대구경 레이저 광집속장치의 쿠데(Coude) 광경로를 구성하는 레이저 반사경들의 레이저 빔조사에 의한 열변형과 이에 따른 광파면 왜곡에 대한 연구를 수행하였다. 쿠데 광경로는 연결거울 3개와 고속조종거울 1개로 구성된다. 반사경은 레이저 빔 파장에 대하여 99.5%의 반사율을 갖으며, 반사경 거울면에 조사된 레이저 에너지는 초당 500 W 정도가 흡수된다. 레이저 빔을 5초 동안 조사하면서 유발된 열하중에 의한 거울의 열 변형과 이에 따른 광파면 왜곡을 분석하였다. 광파면 왜곡은 연결거울의 경우 334 nm_PV, 98 nm rms로 나타났으며 고속조종거울은 $11.5\;{\mu}m$_PV, $3\;{\mu}m$ rms로 나타났다.

• 제어로봇시스템학회:학술대회논문집
• /
• 제어로봇시스템학회 1997년도 한국자동제어학술회의논문집; 한국전력공사 서울연수원; 17-18 Oct. 1997
• /
• pp.1364-1366
• /
• 1997

To operate electric power systems economically and stably, and to supply the electric power of good quality, it is necessary that the measured information (current, voltage, and so on) be detected and transmutted with high reliability and high effieincy. For the reason, the optical magnetic field sensor is possible to rapidly detect to over current and recover when electric power line have fault. In addition, the optical sensor have no electro magnetic distortion and no electric insulation. In this study, we designed OCR(Over Current Relay) using optical sensor. The designed OCR using optical sensor was measured characteristic and compared contentional OCR. This system have highest optical advantages and reliability.

• Journal of information and communication convergence engineering
• /
• 제14권2호
• /
• pp.71-77
• /
• 2016

The combination of dispersion management (DM) and midway optical phase conjugation (OPC) is one of the promising techniques for compensating for optical signal distortion due to group velocity dispersion and nonlinear fiber effects. However, in this combination technique, midway OPC restricts the flexible optical link configuration. Therefore, the possibility of implementing the flexible optical link configuration with non-midway OPC applied to complete inline DM links is investigated in this study. It is confirmed that although the compensation using non-midway OPC for the distorted WDM channels is less effective than that using midway OPC, when non-midway OPC is placed at positions closer to the transmitters, the deployment of precompensation (i.e., the sequence of DCF + SMF)-OPC-postcompensation (i.e., the sequence of SMF + DCF) is more advantageous for the compensation. On the other hand, inverse deployment with respect to OPC (i.e., postcompensation-OPC-precompensation) is more advantageous when non-midway OPC is placed at positions closer to the receivers.

• Journal of information and communication convergence engineering
• /
• 제13권4호
• /
• pp.228-234
• /
• 2015

The system performance improvement in dispersion managed (DM) links combined with optical phase conjugator (OPC) for compensating for optical signal distortion due to group velocity dispersion and nonlinear fiber effects has been reported. However, in DM link combined OPC, the equalities of the lengths of single-mode fibers (SMFs), the length of dispersion compensating fibers (DCFs), the dispersion coefficient of DCF, and the residual dispersion per span (RDPS) with respect to an OPC restrict a flexible link configuration. Thus, in this paper, we propose a flexible optical link configuration with inequalities of link parameters, the so-called "pseudo-symmetric configuration." Simulation results show that, in the restricted RDPS range of 450 ps/nm to 800 ps/nm, the improvement in the system performance of the proposed pseudo-symmetrically configured optical links is better than that of the asymmetrically configured optical links. Consequently, we confirmed that the proposed pseudo-symmetric configuration is effective and useful for implementing a reconfigurable long-haul wavelength-division multiplexing (WDM) network.

• Journal of information and communication convergence engineering
• /
• 제16권2호
• /
• pp.67-71
• /
• 2018

The various techniques to compensate for the signal distortion due to the group velocity dispersion (GVD) and nonlinear Kerr effects of optical fibers in the optical links have been proposed in the literature. We propose a flexible dispersion-managed link configuration consisted of single-mode and dispersion-compensating fibers with irregular dispersion coefficients over all fiber spans, and an optical phase conjugator added midway along the optical links. By distributing the lengths of the single mode fibers, we achieve a flexible optical link. The simultaneous ascending and descending distribution of the single-mode fiber lengths before and after the optical phase conjugator, respectively, best compensates the distorted wavelength division multiplexed signals in the optical link with non-fixed coefficients. Our result is consistent with those of our previous work on fixed coefficients. Therefore, to improve the compensation at any magnitude of dispersion coefficient, we must artificially distribute the lengths of the single-mode fibers into a dispersion-managed link.

• 대한원격탐사학회:학술대회논문집
• /
• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
• /
• pp.628-632
• /
• 2005

Remote sensing through atmospheric turbulence had been hard works for a long time, because wavefront distortion due to the Earth's atmospheric turbulence deteriorates image quality. But due to the appearance of adaptive optics, it is no longer difficult things. Adaptive optics is the technology to correct random optical wavefront distortions in real time. For past three decades, research on adaptive optics has been performed actively. Currently, most of newly built telescopes have adaptive optical systems. Adaptive optical system is typically composed of three parts, wavefront sensing, wavefront correction and control. In this work, the wavefront sensing technology for adaptive optical system is treated. More specifically, shearing interferometers and Shack-Hartmann wavefront sensors are considered. Both of them are zonal wavefront sensors and measure the slope of a wavefront. . In this study, the shearing interferometer is made up of four right-angle prisms, whose relative sliding motions provide the lateral shearing and phase shifts necessary for wavefront measurement. Further, a special phase-measuring least-squares algorithm is adopted to compensate for the phase-shifting error caused by the variation in the thickness of the index-matching oil between the prisms. Shack-Hartmann wavefront sensors are widely used in adaptive optics for wavefront sensing. It uses an array of identical positive lenslets. And each lenslet acts as a subaperture and produces spot image. Distortion of an input wavefront changes the location of spot image. And the slope of a wavefront is obtained by measuring this relative deviation of spot image. Structures and measuring algorithms of each sensor will be presented. Also, the results of wavefront measurement will be given. Using these wavefront sensing technology, an adaptive optical system will be built in the future.

• 한국통신학회논문지
• /
• 제19권8호
• /
• pp.1433-1445
• /
• 1994

본 논문에서는 이축 투사 합성 분리함수(OA-pSDF) 근기한 가간섭성 광상관 시스템을 해석하고 이를 광학적으로 구현하고, 사용된 정합필터는 전형적인 pSDF와 단일 기준 평면파를 다중화하여 합성하였다. 합성된 pSDF는 이진위상필터(BPOF)로 변환되어 고가의 공간광변조기 대신 실시간 광상관 시스템에 사용될 수 있도록 컴퓨터 홀로그램(CGH)으로 제작되었다. 특성시험에서 OA-pSDF는 변형불변 특성과 부분집합 영상의 불변에도 좋은 성능을 보임을 알 수 있었다. 시뮬레이션과 광실험에서 제안된 OA-pSDF BPOF는 기존 BPOF의 크기, 회전, 비동일 평면에서의 변위 등에 성능이 저하되는 단점을 극복하고 출력 평면상에서 주어진 위치에서의 상관값을 관측함으로써 클래스간의 분별 또는 동일 클래스로의 인식 등에 훌륭한 분별력을 가짐을 확인할 수 있었다.

• 한국광학회지
• /
• 제31권2호
• /
• pp.88-95
• /
• 2020

본 연구에서는 헤드업 디스플레이에서 발생하는 왜곡수차와 양안시차를 정량적으로 분석 및 보정하는 방법을 제시한다. 비대칭적인 왜곡수차를 분석하기 위해 다섯 종류의 왜곡수차를 제시하고, 이를 아이박스의 중심부에서 측정된 왜곡수차로부터 다른 4개의 가장자리에서 측정된 왜곡수차의 변화량을 상대적인 왜곡으로 정의하였다. 또한 아이박스 내 6개의 양안 위치에서 수렴 양안시차 및 발산 양안시차에 대해 정의하고 평가하였다. 이런 분석 방법을 이용하여 아이박스 내 눈의 위치에 따른 양안시차 및 왜곡수차 변화량을 제한조건으로 두어 최적설계를 진행하여 왜곡수차 및 양안시차가 보정 된 헤드업 디스플레이용 광학계를 구성하였다.

• 한국광학회지
• /
• 제20권2호
• /
• pp.87-93
• /
• 2009

스테레오 영상에서 관찰자의 위치 변화는 왜곡 발생의 주요 원인이다. 특히, 디스플레이 장치의 중심을 기준으로 한 관찰자의 회전 이동은 관찰자 양안의 수평위치가 다르므로 수평, 전후 이동과는 다른 스테레오 영상의 왜곡이 크게 발생하게 된다. 본 논문에서는 전산모사를 통하여 관찰자의 회전이동에 의한 왜곡을 분석하였고 왜곡 보정결과도 보였다. 마지막으로 관찰자의 회전이동과 수평, 전후 이동의 왜곡형태를 비교를 통하여 두 이동에서 나타나는 왜곡의 형태가 다름을 보였다.