• Title/Summary/Keyword: signal noise

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Finite impulse response design based on two-level transpose Vedic multiplier for medical image noise reduction

  • Joghee Prasad;Arun Sekar Rajasekaran;J. Ajayan;Kambatty Bojan Gurumoorthy
    • ETRI Journal
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    • v.46 no.4
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    • pp.619-632
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    • 2024
  • Medical signal processing requires noise and interference-free inputs for precise segregation and classification operations. However, sensing and transmitting wireless media/devices generate noise that results in signal tampering in feature extractions. To address these issues, this article introduces a finite impulse response design based on a two-level transpose Vedic multiplier. The proposed architecture identifies the zero-noise impulse across the varying sensing intervals. In this process, the first level is the process of transpose array operations with equalization implemented to achieve zero noise at any sensed interval. This transpose occurs between successive array representations of the input with continuity. If the continuity is unavailable, then the noise interruption is considerable and results in signal tampering. The second level of the Vedic multiplier is to optimize the transpose speed for zero-noise segregation. This is performed independently for the zero- and nonzero-noise intervals. Finally, the finite impulse response is estimated as the sum of zero- and nonzero-noise inputs at any finite classification.

Characteristics of Real-time Implementation using the Advanced System Controller in ANC Systems (개선된 시스템 제어기를 사용한 능동소음제어의 실시간 구현 특성)

  • Moon, Hak-ryong;Shon, Jin-geun
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.64 no.4
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    • pp.267-272
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    • 2015
  • Active noise control (ANC) is a method of cancelling a noise signal in an acoustic cavity by generating an appropriate anti-noise signal via canceling loudspeakers. The continuous progress of ANC involves the development of improved adaptive signal processing algorithms, transducers, and DSP hardware. In this paper, the convergence behavior and the stability of the FxLMS algorithm in ANC systems with real-time implementation is proposed. Specially, The advanced DSP H/W with dual core(DSP+ARM) and API(application programming interface) S/W programming was developed to improve the real-time implementation performance under the FxLMS algorithms of input noise such as road noise environment. The experimental results are found to be in good agreement with the theoretical predictions.

Signal Detection in Non-Additive Noise Using Rank Statistics: Signal-Dependent Noise and Random Signal Detection (비가산성 잡음에서 순위 통계량을 이용한 신호 검파 : 신호의존성 잡음과 확률 신호 검파)

  • 송익호;김상엽;김선용;손재철
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.15 no.11
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    • pp.955-961
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    • 1990
  • Test statistics are obtained for detection of weak signals in signal-dependent noise using rank statistics. A generalized model is used in this paper in order to consider non-additivenoise as well as purely-additive noise. Locally optimum rank detectors for the model are shown to have similarity to locally optimum detectors and to be generalizations of these for the purely-additive noise model. A similar result is obtained for multi-input cases.

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Noise reduction system using time-delay neural network (시간지연 신경회로망을 이용한 잡음제거 시스템)

  • Choi Jae-Seung
    • Journal of the Institute of Electronics Engineers of Korea SP
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    • v.42 no.3 s.303
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    • pp.121-128
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    • 2005
  • On the research field for speech signal, neural network mainly uses for the category classification in speech recognition and applies to signal processing. Accordingly, this paper proposes a noise reduction system using a time-delay neural network, which implements the mapping from the space of speech signal degraded by noise to the space of clean speech signal. It is confirmed that this method is effective for speech degraded not only by white noise but also by colored noise using the noise reduction system, which restores the amplitude component of fast Fourier transform.

Image quality enhancement using signal subspace method (신호 부공간 기법을 이용한 영상화질 향상)

  • Lee, Ki-Seung;Doh, Won;Youn, Dae-Hee
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.33B no.11
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    • pp.72-82
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    • 1996
  • In this paper, newly developed algorithm for enhancing images corrupted by white gaussian noise is proposed. In the method proposed here, image is subdivided into a number of subblocks, and each block is separated into cimponents corresponding to signal and noise subspaces, respectively through the signal subspace method. A clean signal is then estimated form the signal subspace by the adaptive wiener filtering. The decomposition of noisy signal into noise and signal subspaces in is implemented by eigendecomposition of covariance matrix for noisy image, and by performing blockwise KLT (karhunen loeve transformation) using eigenvector. To reduce the perceptual noise level and distortion, wiener filtering is implementd by adaptively adjusting noise level according to activity characteristics of given block. Simulation results show the effectiveness of proposed method. In particular, edge bluring effects are reduced compared to the previous methods.

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Noise Shaping Based on Psychoacoustic Model (심리음향모델에 근거한 잡음 형상화)

  • Lee Jingeol
    • Proceedings of the Acoustical Society of Korea Conference
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    • spring
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    • pp.335-336
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    • 2000
  • A psychoacoustic model based noise shaping method is proposed, where noise's presence with a host signal will not be perceptually noticeable. The derivation of imperceptible noise levels from the masking thresholds of the signal involves a deconvolution associated with the spreading function in the psychoacoustic model, which results in an ill-conditioned problem. In this paper, the problem is formulated as a constrained optimization, and it is demonstrated that the solution provides noise shaping where the noise excitation level conforms to the masking thresholds of the signal.

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Objective Evaluation of Vehicle Interior Noise in Transient Operation (주행중 차실 내부 소음의 평가)

  • Jeong, Hyuk;Ih, Jeong-Guon
    • Journal of KSNVE
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    • v.6 no.4
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    • pp.499-502
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    • 1996
  • Interior noise, engine speed and vehicle speed are measured under transient road-load condition and interior noise signal is transformed by using the transient signal analysis methods, such as the spectrogram and wavelet transform. Using the analyzed results, subjective noise metrics such as the loudness, sharpness and articulation index at each vehicle speed can be estimated and characteristics of interior noise for various running modes can be discussed in the viewpoint of noise quality.

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Phase Noise Spectrum of LNB for PSK Multi-mode satellite transmission signal (PSK 고차모드 위성전송을 위한 저잡음 증폭 주파수 변환기의 위상 잡음 해석)

  • Kim, Young-Wan
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.12 no.7
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    • pp.1180-1186
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    • 2008
  • The LNB phase noise of user terminal for high data rate satellite transmission was analyzed in this paper. The phase noise severely affects the service performance in low data rate transmission as well as multi-mode signal for high data rate. As the satellite link frequency is increased, the effects of phase noise for multi-mode signal is increased. The phase noise of LNB, which is operated in high frequency band, is about equal to the transmission system phase noise and have an major effects on service performance degradation. The available transmission mode was analyzed in presence of phase noise of LNB and analysis method for LNB phase noise spectrum distribution was proposed in multi-mode signal.

Active noise control algorithm based on noise frequency estimation (소음 주파수 추정 기법을 이용한 능동소음제어 알고리즘)

  • 김선민;박영진
    • 제어로봇시스템학회:학술대회논문집
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    • 1997.10a
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    • pp.321-324
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    • 1997
  • In this paper, Active Noise Control(ANC) algorithm is proposed based on the estimated frequency estimator of the reference signal. The conventional feedforward ANC algorithms should measure the reference and use it to calculate the gradient of the squared error and filter coefficients. For ANC systems applied to aircrafts and passenger ships, engines from which reference signal is usually measured is so far from seats where main part of controller is placed that the scheme might be difficult to implement or very costly. Feedback ANC algorithm which doesn't need to measure the reference uses the error signal to update the filter and is sensitive to unexpected transient noise like a sneeze, clapping of hands and so on The proposed algorithm estimates frequencies of the desired signal in real time using adaptive notch filter. New frequency estimation algorithm is proposed with the improved convergence rate, threshold SNR and computational simplicity. Reference is not measured but created with the estimated frequencies. It has strong similarity to the conventional feedback control because reference is made from error signal. Enhanced error signal is used to update the controller for better performance under the measurement noise and impact noise. The proposed ANC algorithm is compared with the conventional feedback control.

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The delivery path analysis of community noise : The cepstrum signal processing technique application (소음전달경로 분석 : Cepstrum 적용방안에 관한 연구)

  • Hong, Yun-H.;Kim, Jeung-T.;Kim, Jung-S.
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2008.04a
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    • pp.721-726
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    • 2008
  • Community Noise has been great concerned in public. A road traffic noise has affected too much damage on quiet living environment. In this paper, About measured from the measure point noise and the noise signal processing techniques applied to the occurrence of the noise source with a path to reach this measure point to the measured data to determine signal processor for Complex Cepstrum Analysis of how to apply for research.

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