• 한국광학회:학술대회논문집
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• 한국광학회 1995년도 광학 및 양자전자학 워크샵 논문집
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• pp.105-116
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• 1995

In this paper, we propose a new a new EOST by using the optical JTC(joint transform correlator) as the feature extraction park, because the JTC can adaptively detect the relative displacements of moving targest. Firstly, we derive the BPEJCT(binary phase extraction JTC) which is a phase type JTC and can remove the intracless correlation peaks of the conventional JTC. Then, especially we hardware construction for driving the BPEJTC in real, and with the Kalman target estimation alogorithm, we carried out a target tracking experiment only to show the possibility of real-time implementation of the EOST.

• 한국산업정보학회논문지
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• 제9권2호
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• pp.81-88
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• 2004

잡음을 갖는 영상의 크기와 회전불변 패턴인식을 위한 광 웨이블릿 CHF-fSDF((wavelet circular harmonic function-filter modulation synthetic discriminant function, WCHF-fSDF) 필터를 제안하였다. 웨이블릿 CHF-fSDF 필터는 기준영상에 대하여 크기변화된 영상들을 웨이블릿 변환한 후, 이들로부터 추출한 단일 원형고조함수를 학습영상으로 사용하여 합성한다. 제안된 광 웨이블릿 CHF-fSDF 필터는 정합필터의 형태로서 전통적인 4f 광 상관기에 적용할 수 있도록 하였다. 컴퓨터 모의실험을 통하여 제안된 필터는 크기변화와 회전에 무관한 상관출력을 나타내며 특히 잡음환경하에서 유용함을 확인하였다.

• 한국광학회지
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• 제14권4호
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• pp.383-391
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• 2003

개인의 신원정보 보호를 위하여 새로운 광 정보보호 시스템을 제안하였다. 개인 신원정보의 확인과 인증을 위하여 얼굴영상과 개인식별번호로 구성된 신원정보를 사용하였다. 영상 암호화는 4-f 광상관기의 입력과 푸리에영역에서 랜덤위상패턴을 사용하는 위상암호화 기술을 사용하였다. 그렇지만 암호화된 영상을 복원하는 과정에서 개인의 신원정보가 유출될 가능성이 있다. 이에 대처하기 위하여 신원확인 과정에서 영상을 복원하지 않고 암호화된 영상을 그대로 사용하였다. 암호화된 개인식별번호는 제안된 MMACE_p 필터를 사용하여 분류ㆍ인식하였고, 개인정보의 인증은 OWMF를 사용하여 얼굴영상의 상관치를 구하여 확인하였다. 제안된 MMACE_p 필터는 10개의 암호화된 숫자를 한꺼번에 인식할 수 있도록 4개의 MACE_p필터를 다중화하여 합성하였고, OWMF는 얼굴영상의 분리인식 능력과 SNR을 향상시킬 수 있도록 하였다. 컴퓨터 시뮤레이션을 통하여 제안된 정보보호기술이 개인신원정보 보호에 적용될 수 있음을 보였다.

• International Journal of Concrete Structures and Materials
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• 제10권2호
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• pp.189-203
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• 2016

This paper investigates on the use of advanced optical measurement methods, i.e. 3D coordinate measurement machines (3D CMM) and stereo-vision digital image correlation (3D DIC), for the mechanical analysis of shear deficient prestressed concrete members. Firstly, the experimental program is elaborated. Secondly, the working principle, experimental setup and corresponding accuracy and precision of the considered optical measurement techniques are reported. A novel way to apply synthesised strain sensor patterns for DIC is introduced. Thirdly, the experimental results are reported and an analysis is made of the structural behaviour based on the gathered experimental data. Both techniques yielded useful and complete data in comparison to traditional mechanical measurement techniques and allowed for the assessment of the mechanical behaviour of the reported test specimens. The identified structural behaviour presented in this paper can be used to optimize design procedure for shear-critical structural concrete members.

• 제어로봇시스템학회논문지
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• 제14권5호
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• pp.453-461
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• 2008

In this paper, new inspection method is proposed for the surfaces of lead frame and IC's. Optimal optical system and the accurate algorithm for the surface inspection are needed in machine vision area. The proposed optical system is composed of rectangular oblique light illumination and coaxial light illumination for the higher contrast and the results shows the better performances through experiments. The markings of IC surface are inspected using the accurate proposed method using the partitioned correlation coefficient, and the result shows reduction of under kill ratio compared to the previous method.

• 전자공학회논문지A
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• 제32A권3호
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• pp.58-67
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• 1995

In this paper, we present a new HPEJTC system which is capable of real-time multi-target recognition and tracking with better discrimination by extracting the phase signal of reference function from the JTPS of the conventional optical JTC retaining the amplitude signal of the input function. In order to test the correlation discrimination performance of the HPEJTC system, some experiments are carried out on the scenarios susceptible to the false alarms and missing in which many similar targets are periodically loacted. And, the proposed HPEJTC is analyzed to be the real function version of the POF and finally the possibility of the real-time implementation of the POF is suggested, because it can be implemented by using spatial light modulator, CCD detector and some other optical components.

• KSBB Journal
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• 제25권1호
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• pp.67-72
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• 2010

In this study, we developed a comprehensive correlation for better prediction of the activated sludge concentration in the relationship between measurement of optical density by the Beer's law and sludge properties. Effects of activated sludge properties, which are sludge types and anaerobic storage time, show that absorbance deviation for sludge properties decreased on wavelength of light source near to 950 nm. We also developed a method to measure limitation with non-linear correlation on the measurement of high concentration by the Beer's law using a double layer probe cell and empirical equations.

• Journal of the Optical Society of Korea
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• 제4권1호
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• pp.19-22
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• 2000

A new image encoding and identification scheme is proposed for security verification by us-ing a CGH(computer generated hologram), random phase mask, and a correlation technique. The encrypted image, which is attached to the security product, is made by multiplying a QP- CGH(quadratic phase CGI) with a random phase function. The random phase function plays a key role when the encrypted image is decrypted. The encrypted image can be optically recovered by a 2-f imaging system and automatically verified for personal identification by a 4-f correlation system. Simulation results show the proposed method can be used for both the reconstruction of an original image and the recognition of an encrypted image.

• Journal of the Optical Society of Korea
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• 제20권6호
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• pp.770-777
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• 2016

It has been a challenge for researchers to accurately measure high temperature creep strain online without damaging the mechanical properties of the pipe surface. To this end, a noncontact method for measuring high temperature strain of a main steam pipe based on digital image correlation was proposed, and a system for monitoring of high temperature strain was designed and developed. Wavelet thresholding was used for denoising measurement data. The sub-pixel displacement search algorithm with curved surface fitting was improved to increase measurement accuracy. A field test was carried out to investigate the designed monitoring system of high temperature strain. The measuring error was less than $0.4ppm/^{\circ}C$, which meets actual measurement requirements for engineering. Our findings provide a new way to monitor creep damage of the main steam pipe of a boiler of an ultra-supercritical power plant in service.

• 한국통신학회논문지
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• 제15권4호
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• pp.286-294
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• 1990

본 논문은 A/O광산관기의 실시간 신호 처리에 대하여 이론적으로 분석하고 실험을 통하여 시간적으로 두 신호의 상관함수를 얻는 방법을 연구하였다. 강도변조모드로 동작하는 본 광상관기는 종래의 광상관기에 비해 SNR을 높일 수 있었고 진폭변조모드로 동작하는 기존의 광상관기에 비해 시스템 구성이 간단하고 신호검출이 용이함을 보였다.