• Broadcasting and Media Magazine
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• v.18 no.3
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• pp.40-56
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• 2013

본 연구 논문의 목표는 홀로그래픽 디스플레이 성능평가 항목을 구체적으로 정리하며 성능평가 정의를 기반으로 홀로그래픽 디스플레이의 화질평가 방법을 제안한다. 홀로그래픽 디스플레이를 통하여 제공되는 입체 시 인지요인의 만족지표를 설정하고 디스플레이 되는 홀로그래픽 디스플레이의 광학적 요구 사항과 관련된 성능 평가 항목을 정의 한다. 또한 본 논문에서는 위상 광변조기(Phase SLM)를 이용한 실험장치를 구성하여 획득한 홀로그래픽 재생영상을 분석함으로써 홀로그래픽 디스플레이의 영상이 갖추어야 할 평가지표를 나타낸다. 평가 항목과 관련하여 모듈레이션 전이함수(Modulation Transfer Function)를 이용한 해상도(resolution)와 대조비(contrast)에 대한 결과를 분석하였으며 마지막으로 획득된 간섭무늬(Fringe Pattern)의 랜덤 위상 노이즈(Random Phase Noise)에 따른 화질 저하에 대한 정량 분석결과를 나타낸다.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.642-644
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• 2003

SAC is a compact electro-optical camera for imaging in visible-NIR spectral ranges. SAC provides highresolution images over the wide geometric and spectral ranges: 10 m ground sample distance (GSD) and 50 km swath width in the spectral ranges of 520 ${\sim}$ 890 nm. SAC is designed to produce high quality images: modulation transfer function (MTF) of more than 15 %; signal-to-noise ratio (SNR) of more than 100. The missions of SAC incorporate various imaging operations: multi-spectral imaging; super swath-width imaging with cameras in parallel; along-track stereo imaging with slanted 2 cameras.

• Journal of the Optical Society of Korea
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• v.5 no.2
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• pp.33-36
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• 2001

Common methods of determining the spatial resolution of fiber-optic image guides are by measuring the diameter of individual microfibers or by the use of a resolution test target. However these methods cannot provide enough information of spatial resolution in ultrathin fiber-optic image guides. In this study, a simple method to measure the modulation transfer function (MTF) of an mage guide was developed. The MTFs of ultrathin image guides with 3 and 4${\mu}{\textrm}{m}$ Um diameter were measured by examining transmitted sharp edge image. This method should be especially useful for measuring spatial resolution of ultrahigh resolution image guides with less than 5 ${\mu}{\textrm}{m}$ diameter microfibers because their spatial resolution cannot be determined by individual microfiber diameter due to crosstalk and leaky ray phenomena.

• Journal of Advanced Navigation Technology
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• v.16 no.3
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• pp.518-525
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• 2012

The modulation transfer function is generally used as a method to estimate the characteristics of this kind of optical system because it cannot reappear or implement image of the object perfect. By the way, it is difficult to assess the optical system with existing MTF method since the reaction between diffraction and aberration of aperture is very complicate if the aberration is very small. The MTF has to be calculated considering the numerical aperture, defocusing, OPD and phase difference. We validate its feasibility using bessel function as an estimating method, and then realize it through illustration in this paper.

• Journal of Advanced Navigation Technology
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• v.16 no.2
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• pp.401-408
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• 2012

There is a clear need for characterizing optical components with the growing role played by optical devices in measurement, communication, and photonics. A basic and useful measuring parameter to meet this need, especially for imaging systems, is the Modulation Transfer Function, or MTF. Over the past few decades new instrument, including the laser interferometer, the CCD camera, and the computer have revolutionized the measurement and calculation of the MTF. This has made what was tedious and involved into virtually an instantaneous measurement. We proposed a Simpson approxiamtion method to create MTF graph and illustrated real example to verify its method in this paper. This method is very useful while it is very useful because its error is very minor and small although its approximation.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.11b
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• pp.15-17
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• 2004

The quality of X -ray image is depending on the acquired signal pattern So far, the MTF(modulation transfer function) of medical image system has been obtained through various kinds of calculationprocesses after using SWRF (A square wave response function method) to print out it into films. In this study, a tool has been developed that can help the actual user who actually creates the medical images measure the MTF of the finaldisplay image very simply by applying Borland C++ builder software as well as LEAD tools software for the SWRF calculation process to analyze the MTF even on the display image. Films have been printed out by this newly developed MTF measuring tool under the same conditions with the ones for the existing tools and also the calculation method has shown no difference with any existing SWRF calculation method. By using this, it was found out that the MTF of the resolving power of the computed radiography(CR) Image plate (IP) that is a conventional X-ray detection system Jar the conventional X-ray purpose was about 10% at the range of 3.00 LP/mm.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.34C no.2
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• pp.1-11
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• 1997

We developed a base station modulator ASIC for CDMA digital cellular system. In CDMA digital cellular system, the modulation is performed by convolutional encoding and QPSK with spread spectrum. The function blocks of base station modulator are CRC, convolutional encoder, interleaver pseudo-moise scrambler, power control bit puncturing, walsh cover, QPSK, gain controller, combiner and multiplexer. Each function block was designed by the logic synthesis of VHDL codes. The VHDL code was described at register transfer level and the size of code is about 8,000 lines. The circuit simulation and logic simulation were performed by COMPASS tools. The chip (ES-C2212B CMB) contains 25,205 gates and 3 Kbit SRAM, and its chip size is 5.25 mm * 5,45 mm in 0.8 mm CMOS cell-based design technology. It is packaged in 68 pin PLCC and the power dissipation at 10MHz is 300 mW at 5V. The ASIC has been fully tested and successfully working on the CDMA base station system.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.44 no.5
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• pp.20-27
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• 2007

Generally, the TFT-LCD image signal have nonuniform brightness and are composed of largely varying background signal, noise signal and abruptly changing Mura signal within Mura region. In this paper, Mura region enhancing algorithms using the proposed modified-MTF, which describes how human-visual-system's sensitivity varies in frequency domain, is proposed. The validity of the proposed algorithm was demonstrated ideal 1-dimensional signal and also then it was also tested TFT-LCD image. By the experimental results, the proposed algorithm is very effective in TFT-LCD image Mura enhancement.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.202-207
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• 2002

EOC (Electro-Optical Camera) of KOMPSAT-1 (Korea Multi-Purpose SATellite) has been producing land imageries of the world since January 2000. After image data are acquired by EOC, they are transmitted from satellite to ground via X-band RF signal. Then, EOC image data are generated and pass through radiometric and geometric corrections to generate standard products of EOC images. After radiometric correction on EOC image data, Modulation Transfer Function (MTF) compensation is applicable on EOC images with user's request for better image quality. MTF compensation is concerned with filtering EOC images to minimize the effect of degradations. For Image Receiving and Processing System (IRPE) at KOMPSAT Ground Station (KGS), Wiener filter is used in MTF compensation for EOC images. If the Pointing Spread Function (PSF) of EOC system is known, signal-to-noise power spectra ratio is the only factor in the determination of Wiener filter. In this paper, MTF compensation in IRPE at KGS is introduced and MTF compensated EOC 1R images are generated using Wiener filters with various signal-to-noise power spectra ratios. MTF compensated EOC 1R images are correlated with EOC 1R images for observing linearities between them. As a result, the effect of signal-to-noise power spectra ratio is shown on MTF compensated EOC 1R images.

• Korean Journal of Remote Sensing
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• v.19 no.1
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• pp.43-52
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• 2003

EOC (Electro-Optical Camera) of KOMPSAT-1 (Korea Multi-Purpose SATellite) has been producing land imageries of the world since January 2000. After image data are acquired by EOC, they are transmitted from satellite to ground via X-band RF signal. Then, EOC image data are retrieved and pass through radiometric and geometric corrections to generate standard products of EOC images. After radiometric correction on EOC image data, Modulation Transfer Function (MTF) compensation is applicable on EOC images with user's request for better image quality. MTF compensation is concerned with filtering EOC images to minimize the effect of degradations. For Image Receiving and Processing System (IRPE) at KOMPSAT Ground Station (KGS), Wiener filter is used for MTF compensation of EOC images. If the Pointing Spread Function (PSF) of EOC system is known, signal-to-noise (SNR) power spectra ratio is the only variable which determines the shape of Wiener filter In this paper, MTF compensation in IRPE at KGS is briefly addressed, and MTF compensated EOC images are generated using Wiener filters with various SNR power spectra ratios. MTF compensated EOC images are compared with original EOC 1R images to observe correlations between them. As a result, the effect of SNR power spectra ratio on MTF compensated EOC images is shown.