• Journal of Korean Ophthalmic Optics Society
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• v.13 no.2
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• pp.23-28
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• 2008

Purpose: To develop the 2~8X zoom beam expander for the 1064 nm laser source. Methods: After developing the program by which the initial design values of 3-component zoom tracks can be quickly obtaind, we design and develop the zoom beam expander by applying this program and the commercial program of Sigma 2000. Results: In this study, we could develop the program by which the initial design values of zoom tracks can be quickly obtaind, and by applying this program and the commercial program of Sigma 2000 we could design and develop the zoom beam expander for 1064 nm which is able to zoom from 2${\times}$ to 8${\times}$. The developed zoom beam expander has an efficient diameter of the incidence side of 8 mm, an efficient diameter of the exit side of 32 mm, and a capacity with the finite ray aberration within 0.0001rad. Because the overall length (OAL) is restricted between 125 mm and 135 mm, the change of the whole barrel length which is caused by variations of the zoom driving becomes to be within 10 mm. Conclusions: we could develop the program by which the initial design values of zoom tracks can be quickly obtaind, and by applying this program we could design and develop the zoom beam expander for 1064 nm which is able to zoom from 2${\times}$ to 8${\times}$.

• Journal of Digital Convergence
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• v.15 no.12
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• pp.531-541
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• 2017

Realistic videos using multi-view videos are created so that the contents shown on multi-view displays or screens look realistic. These images have been mostly used for special videos for exhibition, but, recently, systems such as Screen X have given rise to multi-view images as a format for storytelling contents such as movies. This study used HD-level broadcasting digital video camera with three zoom lenses for shooting wide to close-up shots focusing on a person, in the same way as Screen X, and identified and analyzed problems found during multi-view image registration correction. The results of this study suggested, provided the shooting technique and equipment are improved, the multi-view format can be used for conveying stories and information. Future research will need to investigate and supplement relevant techniques that will enable production of high-quality multi-view image contents by using a cinema-grade camera with standard lenses, instead of using broadcasting-grade zoom lenses.

• Korean Journal of Optics and Photonics
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• v.14 no.6
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• pp.613-622
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• 2003

The multi-configurative microscopic system for inspecting the wire-bonding of reed frame is designed. Rays refracted by objective lens group which is composed of common lens group of x2 and x6 are splitted by beam-splitter, and Rays through the central region and the boundary region of the object imaged at x2 and x6 through imaging lens groups, respectively. The depth of wire structure on the reed frame has about $\pm$3 mm, in order to observe by uniform magnification without the dependency on the variation of objective distance generated by the depth of wire structure on the reed frame, imaging lens groups should be moved on nonlinear locus like mechanically compensated zoom lenses. The nonlinear equations for zoom locus are derived by using the Gaussian bracket. Refraction powers and positions of each groups are numerically determined by solving the equations, and initial design data for each groups is obtained by using Seidel third order aberration theory. The optimization technique is finally utilized to obtain this microscopic system.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.119-125
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• 2000

We analyzed to calculate optical capacity after we chose established 2 component zoom copier lens system in this research. As the lens system is zoom lens system of finite object point, it has moving area limited not like to use generally camera zoom lens of infinite object point because it moves between object and image plane. The magnification of optical system can obtain -1.41~-0.64 i.e., extended or shortened image as transverse magnification, and it acquires f/12 and about $20^{\circ}$ field of view. Although this 2 component zoom copier lens system will be down resolution and dark compared with f/2.8 acquired at camera lens, it will be possibile to be able to make large aperture and it can acquire more better correct aberration with the addition of auxiliary group forward or backward.

• Journal of the Institute of Electronics and Information Engineers
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• v.49 no.11
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• pp.74-85
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• 2012

In this paper, we propose a optical property correction technique for a low-cost heterogeneous stereoscopic camera. Three main optical properties of a stereoscopic camera are zoom, focus, and DOF(depth of field). The difference or mis-match of these properties between two stereoscopic videos are the main causes of the visual fatigue to human eyes. The proposed correction technique reduces the difference of the optical properties between the stereoscopic videos and produces high-quality stereoscopic videos. To correct the zoom difference, a LUT(look-up table) is established to match the zoom ratio between the stereoscopic videos. To correct the DOF difference, the magnitude of image edge is measured and the lens iris is changed to control the DOF of the camera. A vertical-type stereoscopic rig is developed for the experiments of the optical property correction. Based on the experimental results, we find that a low-cost heterogeneous stereoscopic camera can be implemented, which can yield low visual fatigue to human eyes.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2007.02a
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• pp.68-71
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• 2007

자연스러운 가상현실 제작을 위해서는 정확한 카메라 보정(camera calibration) 과정이 필수적인 선결 조건으로 요구된다. 그러나 기존의 영상처리에 의한 카메라 보정 방식은 특징점 추출에서의 에러 발생과 여러 장의 영상을 촬영해야 하는 등의 단점으로 줌렌즈 카메라 보정에는 사용되기 힘들었다. 본 논문에서는 카메라보정 객체의 모델에 기반하여 카메라 파라미터를 최적화하는 방법으로 카메라 보정을 구현하였다 최적화 방법으로는 경사기반 방식에 비해 국부최적점에 강인한 것으로 알려진 유전자알고리즘(genetic algorithm)을 사용하였다. 카메라 보정 객체에 낮은 공간주파수성분을 보강하고, 목적함수에 영상의 밝기 정보를 포함하며, 유전자알고리즘을 사용함으로써 초기치가 최적점에서 멀리 떨어져있는 경우에도 수렴이 가능함을 실험적으로 확인하였다.

• Korean Journal of Optics and Photonics
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• v.6 no.1
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• pp.1-7
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• 1995

A IR zoom telescope system was designed for thermal imagery. The magnification is 4-14 and the focal length of eye piece is 25 mm. First, the frame was built up with first order optics and started design with 3rd order optics. There after, we can get the final design by optimization technique through finite ray tracing. The optical system was optimized with ray aberration or angular aberration including higer orders. Finally, The performance of the optical system was accessed by calculating the diffraction MTF from the design data. data.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.13-18
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• 2002

This study conducts the soft contact lenses user's understanding and contentment of training while at the place of purchase. It is based on a questionnaire to the residents in and outside the Masan area, aged between ten to thirty, who have worn soft contact lenses. It examines the training of using contact lenses and lens-care products, the period of wearing lenses, exchanging lenses, sterilizing lenses, side effects of using lenses or the periodic examination, and the understanding and contentment of the users during the training. The results of the research are as below : First, the understanding of training of using lenses, using lens-care products, the period of wearing lenses, exchanging lenses was high, but it was low for the training of sterilizing lenses, side effects of wearing lenses or the periodic examination. Second, the contentment of training of using lenses, lens-care products, the period of wearing lenses, exchanging lenses was high, but low for the training of sterilizing lenses, side effects of wearing lenses or the periodic examination. Therefore, the trainer of the contact lenses must easily and sincerely explain sterilizing lenses, the side effects of using lenses and the periodic examination, cheek with the users, and provide guidelines so as to improve the understanding and the contentment of training of using contact lenses.

• Clean Technology
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• v.11 no.4
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• pp.205-211
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• 2005

There have been many technologies and materials proposed for realizing microlens array, and plastic injection is recognized as the most promising one because of several merits such as optical properties, impact resistance, formability, lightening and environmental adaptability. Since PR reflow for injection template fabrication enables the lens shape control easier, and the sample technology more effective for mass production, it lowers the cost, enhances integration, and reduces process steps, which leads to be environmentally benign. However injection of polymers may face the difficulty of formability depending on their properties. In order to overcome the difficulty, fast heating/cooling technology was introduced in this study, and microlenses were fabricated and evaluated. template obtained by PR reflow method was heated and cooled fast during injection to fabricate microlens array. PC and PMMA polymer materials were compared, and it was realized that PMMA showed much better formability due to its lower melting temperature. Injection parameters of pressures and velocities were driven out for injection optimization.

• Proceedings of the Optical Society of Korea Conference
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• 2003.07a
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• pp.28-29
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• 2003

각종 렌즈 및 카메라, 망원경, 현미경 등 다양한 광학계들이 설계 및 개발 되고 있는 시점에서 그 성능을 정확하게 평가하는 것이 매우 중요하다. 광학계의 성능 평가를 위해서는 크게 정성적인 방법과 정량적인 방법으로 나눌 수 있는데, 정성적인 방법에 의한 평가는 분해능 표판이나 주기적인 격자의 상을 스크린 등에 결상시킨 후 사람의 눈을 통해서 한계 분해능을 평가하는 방법이다. 정량적인 방법에 의한 평가는 OTF(Optical Transfer Function)를 측정하거나 설계 자료를 통해 계산해 내는 것이다. (중략)