• 한국광학회:학술대회논문집
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• 한국광학회 1999년도 제16회 광학 및 양자전자 학술발표회Proceedings of 16th Optics and Quantum Electronics Conference, 1999
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• pp.128-129
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• 1999

Polygon Mirror Scanning(PMS) is composed of LED array, magnifying lens, polygon mirror and motor. It is important to correct the lens aberrations to gain the image we want to show. In this paper, we have simulated the lens aberration correction to reduce the spherical aberration . We have obtained a aspherical lens which is corrected the spherical aberration.

• Applied Microscopy
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• 제45권1호
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• pp.1-8
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• 2015

We have developed a new HD-2700 (Hitachi High-Technologies Corp., Japan) scanning transmission electron microscope (STEM) that includes an automatic aberration correction function, and a large-solid-angle energy-dispersive X-ray spectroscopy detector that enables high-resolution and sensitive analysis. For observation with atomic resolution, using spherical-aberration-corrected STEM, in order that satisfactory performance of the device can be achieved readily, and within a short time, irrespective of the operator's skill level, a spherical-aberration-correction device with an automatic aberration-correction function was developed. This automatic aberration-correction function carries out the entire correction-related process (aberration measurement, selection and correction) automatically, with automatic selection of the aberrations that require correction, and automatic measurement of the appropriate corrections.

• 디지털융복합연구
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• 제10권10호
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• pp.301-306
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• 2012

본 논문은 머신비전시스템에서 정확한 이미지 획득을 위한 방법을 제안한다. 각종 렌즈에서 요구되는 가장 중요한 기능으로는 실물과 동일한 고품질의 결상을 구현하는 광학적 역할이다. 그러나 머신비전시스템의 입력부에서는 렌즈의 수차로 인하여 왜곡현상이 발생한다. 이러한 문제를 해결하기 위해 실세계 좌표계와 영상 좌표계 간의 변환 관계를 정의해주는 매핑 기능으로, 행렬연산을 통하여 두 좌표간의 거리를 계산하여 정확한 위치를 지정하게 된다. 레이저 정밀 가공작업에서도 Galvanometer를 사용하면 비구면 초점 렌즈에 의하여 발생되고 있는 렌즈 수차를 보정하여야 가공 오차를 개선 할 수 있다. 비구면 렌즈의 수차는 2차원 곡선의 형태를 가지고 있으나, 기존의 렌즈 보정 방법인 선형방법은 매우 많은 점들을 검사하여 보정시간이 많이 소요되는 문제점이 있었다. 가공장비에서 렌즈의 수차로 인하여 발생하는 가공오차를 감소시키기 위하여 Bilinear interpolation 기법을 적용하는 방법을 제안하였다. 제안한 방법은 기존 선형방법과 비교하여 위치 오차의 평균값과 표준편차가 향상되었음 실험을 통하여 입증하였으며 실제 레이저 응용업무에 적용하고 있다.

• ETRI Journal
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• 제41권1호
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• pp.73-83
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• 2019

This paper describes in detail the processing path leading to successful phase images stitching in digital holographic microscope for the extension of the field of view. It applies FIJI Grid/Collection Stitching Plugin, which is a general tool for images stitching, non-specific for phase images. The FIJI plugin is extensively supported by aberration and phase offset correction. Comparative analysis of different aberration correction methods and data processing strategies is presented, together with the critical analysis of their applicability. The proposed processing path provides good background for statistical phase analysis of cell cultures and digital phase pathology.

• 한국통신학회:학술대회논문집
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• 한국통신학회 1986년도 추계학술발표회 논문집
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• pp.194-197
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• 1986

In this paper, for the curvature correction on the scanning plane in laser scanning system, aberration correction method using holographic optical element is suggested. Holoens is selected as a type of holographic zone plate which has aberration correction property. And hologram recording condition is analyzed to find fo property. This hololens is implemented by computer-generated hologram technique. Laser scanning system is organized using desinged hololens and scanning properties of this system are investigated. Using this method optical system structure in laser scanning system can be simplified satisfying both scan linearity and field flatness.

• Journal of the Optical Society of Korea
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• 제19권1호
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• pp.45-54
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• 2015

In this study, a novel parallel wavefront correction system architecture is proposed, and a model-based tabu search (MBTS) algorithm is introduced for this new system to compensate wavefront aberration caused by atmospheric turbulence in a free-space optical (FSO) communication system. The algorithm flowchart is presented, and a simple hypothetical design for the parallel correction system with multiple adaptive optical (AO) subsystems is given. The simulated performance of MBTS for an AO-FSO system is analyzed. The results indicate that the proposed algorithm offers better performance in wavefront aberration compensation, coupling efficiency, and convergence speed than a stochastic parallel gradient descent (SPGD) algorithm.

• 한국광학회지
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• 제30권1호
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• pp.8-14
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• 2019

본 논문에서는 추가적인 광학부품 및 조립공정 없이 차량용 헤드램프의 cut-off line에서 발생하는 색수차를 보정하는 방법과 이를 평가하는 방법을 제안한다. 기하학적인 방법으로 색수차를 보정하기 위해 비구면 프로젝션 렌즈의 볼록면에 tilt를 적용하여 파장별 최대 출사각도의 차이를 줄였으며, 색수차를 평가하기 위한 위치와 광도를 정하고 색 좌표를 통해 색수차 기준을 제시하였다. 이러한 기하학적인 방법을 이용하여 설계된 자동차용 헤드램프를 평가한 결과 cut-off line의 색수차가 상당히 감소되었음을 확인할 수 있었다.

• Journal of the Optical Society of Korea
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• 제19권4호
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• pp.403-408
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• 2015

To evaluate the effects of spherical aberration (SA) correction on optical quality in pseudophakic eyes, we simulated the optical quality of the human eye by computation of the modulation transfer function (MTF). We reviewed the medical records of patients who underwent cataract surgery in Asan Medical Center, retrospectively. A Zywave aberrometer was used to measure optical aberrations at 1-12 postoperative months in patients with AR40e intraocular lens implants. The MTF was calculated for a 5 mm pupil from measured wavefront aberrations. The area under the MTF curve (aMTF) was analyzed and the maximal aMTF was calculated while changing the SA ($-0.2{\sim}+0.2{\mu}m$) and the defocus (-2.0 ~ +2.0 D). Sixty-four eyes in 51 patients were examined. The maximal aMTF was $6.61{\pm}2.16$ at a defocus of $-0.25{\pm}0.66D$ with innate SA, and $7.64{\pm}2.63$ at a defocus of $0.08{\pm}0.53D$ when the SA was 0 (full correction of SA). With full SA correction, the aMTF increased in 47 eyes (73.4%; Group 1) and decreased in 17 eyes (26.6%; Group 2). There were statistically significant differences in Z(3, -1) (vertical coma; P = 0.01) and Z(4, 4) (tetrafoil; P = 0.04) between the groups. The maximal aMTF was obtained at an SA of $+0.01{\mu}m$ in Group 1 and an SA of $+0.13{\mu}m$ in Group 2. Optical quality can be improved by full correction of SA in most pseudophakic eyes. However, residual SA might provide benefits in eyes with significant radially asymmetric aberrations.

• Current Optics and Photonics
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• 제3권1호
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• pp.72-77
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• 2019

This study was performed to analyze the optical aberrations of the cornea induced by myopic refractive surgery. Corneal total higher-order aberrations, spherical aberration and coma for 4-mm and 6-mm pupils were measured using a wave-front analyzer. The amount of aberrations of the oblate corneal optics by the achieved correction was found to be larger than for the prolate corneal shape with complete eye, in an emmetropia control group. The change in corneal shape acts as an optical factor that degrades the quality of the retinal image; it seems to be one of the important factors related to quality of vision.

• 반도체디스플레이기술학회지
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• 제15권3호
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• pp.62-66
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• 2016

Optical system needs to be aligned before its undergoing process, is usually shows coma aberrations, which occurred due to imperfection in the lens or other components results in off-axis point sources, appearing to have a tail like a comet. There are some methods to correct coma aberration. In this paper, to correct coma aberration in optical system, using a robot arm type coordinate measuring machine(CMM). CMMs are widely used to measure the form of accuracy of parts and positioning accuracy of systems. Among them, robot arm type CMM has more advantages than the others, such as its mobility and measuring range. However, robot arm type CMM has lower accuracy than cantilever type CMM. To prove robot arm type CMM's accuracy, several factors were suggested in this paper and the final measuring results were compared to a commercial cantilever type CMM. Based on this accuracy, a typical optical system was successfully aligned by using our robot arm type CMM.