• Title/Summary/Keyword: noise characterization

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A simple proof of analytic characterization theorem for operator symbols

  • Chung, Dong-Myung;Chung, Tae-Su;Ji, Un-Cig
    • Bulletin of the Korean Mathematical Society
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    • v.34 no.3
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    • pp.421-436
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    • 1997
  • In this paper we first give a simple proof of the analytic characterization theorems of the operator symbols by using the characterization theorem for white noise functionals. We next give a criterion for the convergence of operators on white noise functionals in terms of their symbols and then use this result to give a proof for the Fock expansion theorem of operators on white noise functionals.

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ISO/TC 108/WG 28 : Characterization of the Dynamic Mechanical Properties of Resilient Visco-Elastic Materials (ISO/TC 108/WG 28 : Characterization of the Dynamic Mechanical Properties of Resilient Visco-Elastic Materials 활동상황보고)

  • 김광준
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.05a
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    • pp.799-810
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    • 2001
  • 필자는 소음진동공학회가 품질기술원으로부터 ISO/TC108 기계진동 및 충격(Mechanical Vibration and Shock) 간사기관업무를 위탁 받은 후부터 SC6 진동 및 충격 발생시스템(Vibration and Shock Generating Systems)에 대한 한국측 위원으로 일을 해왔다. (중략)

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Improved characterization method for mobile phone camera and LCD display (모바일 폰 카메라와 LCD의 향상된 특성화 방법)

  • Jang, In-Su;Son, Chang-Hwan;Lee, Cheol-Hee;Song, Kun-Woen;Ha, Yeong-Ho
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.45 no.2
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    • pp.65-73
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    • 2008
  • The characterization process for the accurate color reproduction in mobile phone with camera and LCD is popular. The camera and LCD characterization, gamut mapping process is necessary to map the camera's input color stimulus, CIEXYZ value, into the LCD's output color stimulus. Each characterization is the process estimating the relation between input and output signals. In case of LCD, because of output device, the output color stimulus for the arbitrary input signal can be measured by spectro-radiometer However, in the camera, as the input device, the characterization is an inaccurate and needs the manual works in the process obtaining the output signal because the input signal can not be generated. Moreover, after gamut mapping process, the noise is increased because the optimized gamma tone curve of camera for the noise is distorted by the characterization. Thus, this paper proposed the system of obtaining the output signal of camera and the method of gamma correction for the noise. The camera's output signal is obtained by RGB values of patches from captured the color chart image. However, besides the illumination, the error for the location of the chart in the viewfinder is generated when many camera modules are captured the chart. The method of correcting the position to correct the error from manual works. The position of camera is estimated by captured image. This process and moving of camera is accomplished repeatedly, and the optimized position can be obtained. Moreover, the lightness curve of camera output is corrected partly to reduce the noise from the characterization process.

Characterization of Pipe Defects in Torsional Guided Waves Using Chirplet Transform (첩릿변환을 이용한 배관 결함 특성 규명)

  • Kim, Chung-Youb;Park, Kyung-Jo
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.24 no.8
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    • pp.636-642
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    • 2014
  • The sensor configuration of the magnetostrictive guided wave system can be described as a single continuous transducing element which makes it difficult to separate the individual modes from the reflected signal. In this work we develop the mode decomposition technique employing chirplet transform, which is able to separate the individual modes from dispersive and multimodal waveform measured with the magnetostrictive sensor, and to estimate the time-frequency centers and individual energies of the reflection, which would be used to locate and characterize defects. The reflection coefficients are calculated using the modal energies of the separated mode. Results from experimental results on a carbon steel pipe are presented, which show that the accurate and quantitative defect characterization could become enabled using the proposed technique.

A New Algorithm for Ghost Cancellation System (새로운 고스트 제거 알고리즘)

  • Park, Kyung-Bae;Hwang, Hu-Mor
    • Proceedings of the KIEE Conference
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    • 1995.07b
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    • pp.904-906
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    • 1995
  • Based on the detection of the size of datas of multipath channel characterization, we propose a new algorithm. called the impulse size based adaptive median filter(ISMF), for ghost cancellation system. The ISMF consists of two levels. The first one is the impulse noise size detection level and the second one is the adaptive median filtering level to remove the impulse noise detected. Test results confirm that the proposed ISMF removes impulse noise due to multipath channel characterization while preserving signal as well as ghosts so that the LMS algorithm performs effectively.

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A Study on the Active Noise Control System for Road Noise Reduction Implementation and Characterization of Directional and Non-directional Speaker (도로 소음 저감용 능동소음 제어시스템의 구현과 지향성 및 무지향성 스피커의 특성 고찰)

  • Moon, Hak-Ryong;Lim, You-Jin
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.62 no.4
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    • pp.192-197
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    • 2013
  • Road traffic noise barriers being used to reduce the noise, but the city surroundings inhibition, ecosystem disturbance, and it is difficult to maintain. Can enhance or complement the existing noise barrier performance, so that it is necessary to develop an electronic noise-reduction system In this paper, we proposed an electronic road noise reduction devices to reduce road noise for a DSP-based signal processing and analog signal input-output controller. In order to verify the control performance, we performed noise reduction experimentation of ANC by filtered-X LMS algorithm and traffic noise signal injection. The controller is equipped with noise reduction algorithms were tested on the characteristics of directional and omnidirectional speaker.

Noise-free Distributions Comparison of Bayesian Wavelet Threshold for Image Denoise

  • Choi, Ilsu;Rhee, Sung-Suk;Ahn, Yunkee
    • Communications for Statistical Applications and Methods
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    • v.8 no.2
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    • pp.573-579
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    • 2001
  • Wavelet thresholding is a method for he reduction of noise in image. Wavelet coefficients of image are correlated in local characterization. Thee correlations also appear in he original pixel representation of the image, and they do not follow from the characterizations of the wavelet transform. In this paper, we compare noise-free distributions of Bayes approach to improve the classical threshold algorithm.

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Image Quality Evaluation of Digital X-Ray Detector Using Amorphous Selenium Layer and Amorphous Silicon TFT Array (비정질 셀레늄층과 비정질 실리콘TFT배열을 사용하는 디지털 X-선 검출기의 영상특성 평가)

  • Kim, Chang-Won;Yoon, Jeong-Key;Kim, Jong-Hyo
    • Progress in Medical Physics
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    • v.19 no.4
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    • pp.219-226
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    • 2008
  • In this study, we have conducted characterization of imaging performance for a flat panel digital X-ray detector using amorphous Selenium and a-Si TFT which was developed by the authors. The procedures for characterization were in concordance with internationally recommended standards such as IEC (international electrotechnical commission). The measures used for imaging performance characterization include response characteristic, modulation transfer function (MTF), detective quantum efficiency (DQE), noise power spectrum (NPS), and quantum limited performance. The measured DQEs at lowest and highest spatial frequencies were 40% and 25% respectively, which was superior to that of commercial products by overseas vendor. The MTF values were significantly superior to that of CR and indirect type DRs. The quantum limited performance showed the detector was limited by quantum noise at the entrance exposure level below 0.023 mR, which is sufficiently low for general X-ray examination.

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