• Journal of the Korean Institute of Telematics and Electronics A
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• v.28A no.9
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• pp.662-670
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• 1991

Fast analysis method for calculating the radiation pattern of offset dual reflector antenna are presented. The validity of proposed method was verified by comparing with results of PO/PO, GO/PO, and the equivalent paraboloid method. Proposed method is the series expansion method using the Zernike polynomials. The calculated results by using the Zernike polynomials are in good agreement with obtained results by GO/PO and equivalent paraboloid method except PO/PO.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.2
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• pp.35-39
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• 2009

Purpose: In this study a program was developed to determine corneal aberrations using corneal shape of topographer and represented a wavefront and corneal aberrations using zernike polynomial. Methods: When the pupil size was 6 mm, we calculated new corneal shape data with zernike polynomials using corneal shape data of ORBSCAN topographer. We programmed the wavefront construction using ray tracing for corneal shape, then represented corneal aberrations having zernike polynomial with 6th order and 28 terms. Conclusions: We developed programs to determine a wavefront and corneal aberrations using corneal shape of ORBSCAN topographer. Theses results will be applied to a development of new topographer and prescription of contact lens and OK lens.

• Proceedings of the Optical Society of Korea Conference
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• 2006.07a
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• pp.415-416
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• 2006

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.208-211
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• 2005

The volumetric interferometer, which uses the interference of wavefronts emitted from two single mode fibers, measures the target position in 3-D. In this paper, we suggest a new calculation method which doesn't need a non-linear optimization and an initial guess. We find the relationship between the coefficients of the Zernike polynomials for a spherical wavefront and its center and reconstruct a spherical wavefront by using the Zernike polynomials from two interference fringes like a lateral shearing interferometer. The target position can be obtained from the coefficients of the Zernike polynomials of the reconstructed wavefront. We can get the target position in 3-D with $sub-{\mu}m$ errors in a simulation.

• Journal of KIISE:Software and Applications
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• v.31 no.5
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• pp.563-569
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• 2004

A set of Zernike moments has been successfully used for object recognition or content-based image retrieval systems. Real time applications using Zernike moments, however, have been limited due to its complicated definition. Conventional methods to compute Zernike moments fast have focused mainly on the radial components of the moments. In this paper, utilizing symmetric/anti-symmetric properties of Zernike basis functions, we propose a fast and efficient method for Zernike moments. By reducing the number of operations to one quarter of the conventional methods in the proposed method, the computation time to generate Zernike basis functions was reduced to about 20% compared with conventional methods. In addition, the amount of memory required for efficient computation of the moments is also reduced to a quarter. We also showed that the algorithm can be extended to compute the similar classes of rotational moments, such as pseudo-Zernike moments, and ART descriptors in same manner.

• Proceedings of the Optical Society of Korea Conference
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• 2002.07a
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• pp.32-33
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• 2002

적응광학계(adaptive optics system ; AO)는 파면을 파면측정장치로 측정하고 제어용 컴퓨터를 사용하여 파면보정장치를 구동함으로써 파면의 왜곡 및 수차를 보정하는 장치로, 최근 천문학 및 의료분야에서 활용되고 있다. 적응광학계의 제어는 파면을 영역별로 나누어 제어하는 zonal 방법과 모드로부터 제어하는 modal 방법이 있다. 본 연구에서는 파면 측정 장치(wavefront sensor ; WFS)인 Shack-Hartmann sensor로 측정된 파면의 기울기 정보로부터 Zernike 다항식의 계수를 계산하여 수차의 정보를 구현하고, 왜곡된 파면을 실시간으로 보정하기 위하여 Zernike 계수로부터 위상을 재구성한 후 보정장치인 변형거울을 제어하는 방법으로 파면을 보정하였다. (중략)

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1995.10a
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• pp.384-387
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• 1995

Two axes lateral-shearing interferometer(LSI) specially devised for production line inspection lenses is presented. The interferometer composed with four prisms and a dove prism can test the lens performance including asymmetric aspheric lens. The dove prism which rotates the input image with respect to optical axis makes it possible. The wavefront passing through the test lens is reconstsucted by the phase derivative obtained form the two axes LSI system. Zernike-polynomials fitting of this wavefront is presented for determinating quantitative aberration of aspherical lenses.

• Journal of Aerospace System Engineering
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• v.17 no.4
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• pp.18-27
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• 2023

In this paper, the structural-thermal-optical performance analysis of the mirror was performed by setting the laser heat source as the boundary condition of the thermal analysis. For the laser heat source model, the Beer-Lambert model considering semi-transparent optical material based on Gaussian beam was selected as the boundary condition, and the mechanical part was not considered, to analyze the performance of only the mirror. As a result of the thermal analysis, thermal stress and thermal deformation data due to temperature change on the surface of the mirror were obtained. The displacement data of the surface due to thermal deformation was fitted to a Zernike polynomial to calculate the optical performance, through which the performance of the mirror when a high-energy laser was incident on the mirror could be predicted.

• Journal of the Korean Society for Precision Engineering
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• v.27 no.2
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• pp.50-59
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• 2010

In this paper, two kind of free-form progressive addition lenses (PALs) were designed with Zernike polynomial surface and anatomically accurate finite presbyopic schematic eyes which have aspheric cornea, aspheric GRIN crystalline lens, aspheric retina, and Gaussian apodization factor. Geometrical and diffraction MTFs were used for the optimization process in sequence. 5th orders of Zernike polynomials were used for the evaluation of progression zones of the two examples. The target MTF was set as 0.22 at 100 lp/mm which satisfies the standard visual resolution. These examples were fabricated with a CNC diamond turning machine controlled by slow tool servo (STS). After polishing process, the wavefront aberrations were measured with a laser interferometer on the ten test points across the progression zones and then compared with three current commercially available PALs on the optical performance. Astigmatic aberrations of the examples are very lower than the three selected PALs and have more increased stabilized progressive intermediate zones and near zones. It is expected to give better clear and comfortable distance, intermediate and near visions than other conventional PALs and to improve the adaptability of presbyopic patients to PALs.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.18 no.1
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• pp.39-46
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• 1993

In this paper, an offset paraboloidal reflector antenna satisfied efficiency of over 60% and sidelobe envelope line of 29-25$log\theta$ was designed and manufactured for Ku-band VSAT(Very Small Aperture Terminal) antenna. The radiation patterns of experimental antenna were computed by applying the series expansion method using the Zernike polynomials. The measured patterns are in good agreement with the computed results. The Gain, efficiency, and sidelobe envelop line fairly well satisfy the design specifications except first sidelobe level.