• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.54-57
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• 2003

본 논문에서는 멀티웨이브릿 변환영역에서 통계적 모델과 지각적 동조특성을 이용한 적응적 디지털 워터마킹 기법을 제안한다. 워터마크는 4레벨로 분해된 멀티웨이브릿 변환영역에서 최저주파 영역과 최고주파 대역들을 제외한 중간 및 고주파 영역에, 인간 시각 시스템(human visual model BWS)을 이용한 JND(just noticeable difference) 특성과 NVF(noise visibility function)를 이용한 통계적 특성을 기반으로 정상상태 가우시안 모델과 비정상상태 가우시안 모델에 따라 지각적 동조 특성을 이용하여 적응적으로 삽입된다. 실험 결과 제안한 방법에서 에지나 텍스쳐 영역에 더 강하게 삽입할 수 있었고, 평탄영역에서 보다 적응적으로 은닉할 수 있었으며 정상상태 가우시안 모델에서 지각적 동조특성을 이용한 방법이 더 우수한 비가시성과 강인성을 확인하였다.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.157-160
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• 2003

발전소에서 운전중인 기계들의 안전운전과 예지 보전을 위하여 발전설비의 고장 감지 및 진단과 상태 모니터링은 중대한 역할을 담당하고 있다. 이 연구에서는 설비의 안전하고 신뢰적인 운전을 위한 기계의 작동상태를 사운드 정보로 획득하고 분석하는 시스템을 제안하였다. 사운드 정보의 사용은 적은 양의 채널의 사용으로 많은 기계 및 설비의 이상 유무의 판별을 가능케 하며, 이를 획득하기 위하여 3개의 마이크로폰, 다채널 A/D변환기, 다채널 I/O Sound Card(Soundtrack DSP24) 및 PC로 시스템을 구성하였다. 소프트웨어 개발언어로서 Microsoft Visual C＋＋ 및 MATLAB을 이용하였다. 화력 발전소에 운전중인 주요기계들의 사운드 정보를 취득하여 취득한 기계별 사운드 정보를 이용하여 주파수 특성을 파악하고, 이를 이용하여 기기의 운전 상태진단을 가능하게 한다.

• Proceedings of the KOSOMBE Conference
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• v.1996 no.05
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• pp.151-153
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• 1996

The purpose of this paper is the development of Integrated Bio-signal Management System(IBMS) using the network. IBMS is the system to manage the medical signals that measured from the each independent medical measurement system module. Each has a LAN. We developed the file-server network using Novell Netware. Also, we developed the Graphic User Interface software for IBMS using Visual C++ at Windows 3.1.

• Journal of Information Processing Systems
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• v.15 no.1
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• pp.169-180
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• 2019

Transmitting visual information over a broadcasting network is not only prone to a copyright violation but also is a forgery. Authenticating such information and protecting its authorship rights call for more advanced data encoding. To this end, electronic watermarking is often adopted to embed inscriptive signature in imaging data. Most existing watermarking methods while focusing on robustness against degradation remain lacking of measurement against security loophole in which the encrypting scheme once discovered may be recreated by an unauthorized party. This could reveal the underlying signature which may potentially be replaced or forged. This paper therefore proposes a novel digital watermarking scheme in temporal-frequency domain. Unlike other typical wavelet based watermarking, the proposed scheme employed the Lorenz chaotic map to specify embedding positions. Effectively making this is not only a formidable method to decrypt but also a stronger will against deterministic attacks. Simulation report herein highlights its strength to withstand spatial and frequent adulterations, e.g., lossy compression, filtering, zooming and noise.

• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.623-626
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• 2002

Extreme development in digital multimedia has raised anxiety in the minds of copyrighted content owners. This has resulted in the creation of several watermarking techniques. This paper, proposes a method of embedding a perceptually transparent digital signal, named semi-fragile watermark in the wavelet domain, utilizing the characteristics of the human visual system. So as to detect attacks inflicted on the content and use an algorithm to specify the character of the attack.

• Proceedings of the IEEK Conference
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• 2000.06d
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• pp.114-117
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• 2000

In this paper, we proposed robust digital image watermarking based on modulation transfer function (MTF) of human visual system (HVS). Using the proposed method, robust watermarking is possible both in common image processing operations such as cropping and lossy compression and in geometrical transforms such as rotation, scaling, and translation, because it can embed watermark and template signal maximally using MTF of HVS. Experimental results show that the proposed watermarking method is more robust to several common image processing operations and geometrical transforms.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.157.1-157
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• 2001

A new methodology is presented to diagnose faults in equipment plasma. This is accomplished by using neural networks as a pattern recognizer of radio frequency(rf) impedance match data. Using a realtime match monitor system, the match data were collected. The monitor system consisted mainly of a multifunction board and a signal flow diagram coded by Visual Designer. Plasma anomaly was effectively represented by electrical match positions. Twenty sets of fault-symptom patterns were experimentally simulated with experimental variations in process factors, which include rf source power, pressure, Ar and O$_2$ flow rates. As the inputs to neural networks, two means and standard deviations of positions were used ...

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.127.4-127
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• 2001

Inspection and shape measurement of three-dimensional objects are widely needed in industries for quality monitoring and control. A number of visual or optical technologies have been successfully applied to measure three dimensional surfaces. Especially, the shape measurement using an interferometric principle becomes a successful methodology. However, those conventional interferometric methods to measure surface profile have an inherent shortcoming, namely 2∏ ambiguity problem. The problem inevitably happens when the object to be measured has discontinuous shape due to the repetition of interferometric signal with phase period of 2∏. Therefore, in this paper, we choose as a shape measuring method, ...

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.04a
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• pp.675-679
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• 1996

제품의 소형화, 고성능화, 부품의 제작기술의 급속한 발전으로 SMD실장기술은 소형화, 고밀도화로 진 보를 이루어왔다. 그러나, 기존의 PCB 검사 방법으로는 정확하고, 균일한 검사가 어려워 이를 해결할 수 있는 검사 방법이 요구되어 왔다. Machine Vsion에 의한 검사는 균일하고 정확하며, 불량의 유형도 판별하여 전체 공정의 제어가 가능한 방법이다. 본 연구에서는 영상처리에 적합한 영상을 쉽게 얻을 수 있도록 고휘도 LED를 사용하고, 밝기 조절이 가능한 영상획득부를 설계하였으며, Morphology filter룰 사용하여 빠르고, 안정된 noise 제거 및 edge 검출 알고리즘을 구현하였다.

• 제어로봇시스템학회:학술대회논문집
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• 1990.10a
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• pp.825-830
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• 1990

This paper reports the design procedure and testing result of a servo driven pan/tilt device which is capable of tracking arbitrary movement of a specified target object. In order to achieve real-time acquisition of feedback signal, a 2 degrees-of-freedom non-contact type displacement follower is used. The performance of the system is tested for different target velocities and control gains. The result of the research may provide an effective tool for visual transfer in the context of teleoperation.