• Title, Summary, Keyword: Background suppression

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Measurement of MDA of Soil Samples Using Unsuppression System and Compton Suppression of Environmental Radioactivity in Processing Technology (환경 방사능 처리기술에서의 Compton suppression 및 Unsuppression system을 이용한 토양시료의 MDA 측정)

  • Kang, Suman;Im, Inchul;Lee, Jaeseung;Jang, Eunsung;Lee, Mihyeon;Kwon, Kyungtae;Kim, Changtae
    • Journal of the Korean Society of Radiology
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    • v.8 no.6
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    • pp.293-299
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    • 2014
  • Compton suppression device is a device by using the Compton scattering reaction and suppress the Compton continuum portion of the spectrum, so can be made more clear analysis of gamma ray peak in the Compton continuum region. Measurements above background occurs or, radioactivity counts of radioactivity concentration value of $^{40}K$ nuclides $^{137}Cs$ and natural radioactivity artificial radioactivity detected from the surface soil sample, unwanted non-target analysis and interference peak who dotted line you know the calibration of the measurement energy is allowed to apply the (Compton suppression) non-suppressed spectrum inhibition spectrum and (Compton Unsuppression) the background to the measured value of the activity concentration value of the standard-ray source is detected relative to the peak of By measuring according to the different distances cause $^{137}Cs$, and comparative analysis of the Monte Carlo simulation, in order to obtain a detection capability for efficient, looking at the Compton inhibitor, as the CSF value increases with increase in the distance, more It was found that the background due to Compton continuum of the measured spectrum suppression mode Compton unrestrained mode can know that the Compton suppression many were made, using a $^{137}Cs$ is reduced.

A Study on Suppression of Ultrasonic Background Noise Signal using wavelet Transform (Wavelet변환을 이용한 초음파 잡음신호의 제거에 관한 연구)

  • 박익근
    • Journal of The Korean Society of Manufacturing Technology Engineers
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    • v.8 no.1
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    • pp.135-141
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    • 1999
  • Recently, advance signal analysis which is called "Time-Frequency Analysis" has been developed. Wavelet and Wigner Distribution are used to the method. Wavelet transform(WT) is applied to time-frequency analysis of waveforms obtained by an ultrasonic pulse-echo technique. The Gabor function is adopted as the analyzing wavelet. Wavelet analysis method is an attractive technique for evolution of material characterization evoluation. In this paper, the feasibility of suppression of ultrasonic background noise signal using WT has been presented. These results suggest that ultrasonic background noise ginal can be suppressed and enhanced even for SNR of 20.8 dB. This property of the WT is extremely useful for the detecting flaw echos embedded in background noise.und noise.

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A New Integrated Suppression Algorithm Based on Combined Power of Acoustic Echo and Background Noise (결합된 음향학적 반향 및 배경 잡음 전력에 기반한 새로운 통합 제거 알고리즘)

  • Park, Yun-Sik;Chang, Joon-Hyuk
    • The Journal of the Acoustical Society of Korea
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    • v.29 no.6
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    • pp.402-409
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    • 2010
  • In this paper, we propose an efficient integrated suppression algorithm based on combined power of acoustic echo and background noise. The proposed method combines the acoustic echo and noise power by the weighting parameter derived from the decision rule based on the estimated echo to noise power ratio. Therefore, in the proposed approach, the acoustic echo and noise signal are able to be reduced through only one suppression filter based on the estimated combined power. The proposed unified structure improves the problems of the residual echo and noise resulted from the conventional unified structure where the noise suppression (NS) operation is placed after the acoustic echo suppression (AES) algorithm or vice versa. The performance of the proposed algorithm is evaluated by the objective test under various environments and yields better results compared with the conventional scheme.

Comparison of Noise Suppression Methods in Voice CODEC (음성부호화기에서의 잡음제거 방식 비교)

  • 이진걸;기훈재
    • Proceedings of the IEEK Conference
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    • pp.1203-1206
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    • 1998
  • Considerable research in the last three decades has examined the problem of enhancement of speech degraded by additive background noise. We compare traditional methods such as spectral subtraction and Wiener filter, recently proposed psychoacoustic model based methods such as perceptual filter and noise suppression in EVRC in terms of performance and complexity.

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Performance of a Compton Suppression Spectrometer of the SNU-KAERI PGAA Facility

  • Sun Gwang Min;Park Chang Su;Choi H.D.
    • Nuclear Engineering and Technology
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    • v.35 no.4
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    • pp.347-355
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    • 2003
  • The \gamma-ray spectrometer of the PGAA (Prompt Gamma Activation Analysis) facility constructed at HANARO of the Korea Atomic Energy Research Institute was upgraded to the multi-mode spectrometer including the single mode, the Compton suppression mode and the pair mode. The performance of the spectrometer was tested and summarized. The background count rate and the uncertainty of the detection efficiency were reduced greatly in comparison with those before the new installation.

Application of Compton-Suppressed Self-Induced XRF to Spent Nuclear Fuel Measurement

  • Park, Se-Hwan;Jo, Kwang Ho;Lee, Seung Kyu;Seo, Hee;Lee, Chaehun;Won, Byung-Hee;Ahn, Seong-Kyu;Ku, Jeong-Hoe
    • Journal of the Korean Physical Society
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    • v.71 no.9
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    • pp.543-547
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    • 2017
  • Self-induced X-ray fluorescence (XRF) is a technique by which plutonium (Pu) content in spent nuclear fuel can be directly quantified. In the present work, this method successfully measured the plutonium/uranium (Pu/U) peak ratio of a pressurized water reactor (PWR)'s spent nuclear fuel at the Korea atomic energy research institute (KAERI)'s post irradiation examination facility (PIEF). In order to reduce the Compton background in the low-energy X-ray region, the Compton suppression system additionally was implemented. By use of this system, the spectrum's background level was reduced by a factor of approximately 2. This work shows that Compton-suppressed self-induced XRF can be effectively applied to Pu accounting in spent nuclear fuel.

Comparion of Noise Suppression Methods in Voice CODEC (음성코덱에서의 잡음제거 방식 비교)

  • Lee, Jin-Geol
    • The Journal of Engineering Research
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    • v.3 no.1
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    • pp.43-46
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    • 1998
  • Considerable research in the last three decades has examined the problem of enhancement of speech degraded by additive background noise. We compare traditional methods such as spectral subtraction and Wiener filter, recently proposed psychoacoustic model based methods such as perceptual filter and noise suppression in EVRC in terms of performance and complexity.

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Adaptive Noise Suppression system based on Human Auditory Model (인간의 청각모델에 기초한 잡음환경에 적응된 잡음억압 시스템)

  • Choi, Jae-Seung
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • pp.421-424
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    • 2008
  • This paper proposes an adaptive noise suppression system based on human auditory model to enhance speech signal that is degraded by various background noises. The proposed system detects voiced and unvoiced sections for each frame and implements the adaptive auditory process, then reduces the noise speech signal using neural network including amplitude component and phase component. Base on measuring signal-to-noise ratios, experiments confirm that the proposed system is effective for speech signal that is degraded by various noises.

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Noise Suppression Algorithm using Neural Network based Amplitude and Phase Spectrum (진폭 및 위상스펙트럼이 도입된 신경회로망에 의한 잡음억제 알고리즘)

  • Choi, Jae-Seung
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.13 no.4
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    • pp.652-657
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    • 2009
  • This paper proposes an adaptive noise suppression system based on human auditory model to enhance speech signal that is degraded by various background noises. The proposed system detects voiced, unvoiced and silence sections for each frame and implements an adaptive auditory process, then reduces the noise speech signal using a neural network including amplitude component and phase component. Based on measuring signal-to-noise ratios, experiments confirm that the proposed system is effective for speech signal that is degraded by various noises.

The clinical usefulness of fat suppression by chemical shift selective(CHESS) pulse in MRI (MRI에서 화학적 이동 선택(CHESS) pulse에 의한 지방소거의 임상적 유용성)

  • Han, Man-Seok;Yang, Hae-Sool;Jin, Kyung-Soo;Eo, Ik-Soo;Cho, Dong-Heon
    • The KIPS Transactions:PartB
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    • v.14B no.6
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    • pp.431-436
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    • 2007
  • Magnetic Resonance Imaging(MRI) has chemical shift phenomenon between fat and water, and the phenomenon has influence on structure enclosed by fat. Strong signals emitted from fat often generate false artefact, which reflects the importance of fat suppression techniques. There have been a number of researches on fat suppression techniques, but using fat suppression method alone in MRI can cause difficultproblems in diagnosis. This paper aims to study a fat suppression method by Chemical Shift Selective saturation(CHESS). This research describes the theoretical background and the experiment on water and fat phantom with MR instruments. In the experiment, CHESS pulse was designed by utilising Matlap program, and the pulse diagram was generated for the Pre-saturation process. The experiment using water and fat phantom was applied to C-spine, L-spine and Breast, and produced successful fat suppression results. This experiment has proved that the CHESSpulse fat suppression is a very helpful technique in diagnosing medical imaging. This method is a robust and useful technique for both clinical and basic investigators..(Experiment with Chungnam national university hospital G.E 1.5T MR)