Topic
Noise reduction
About: Noise reduction is a research topic. Over the lifetime, 25121 publications have been published within this topic receiving 300815 citations. The topic is also known as: denoising & noise removal.
Papers published on a yearly basis
Papers
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TL;DR: This paper introduces a new ANC algorithm suitable for single-tone noises as well as some specific narrowband noises that does not require the identification of the secondary path, though its convergence can be very slow in some special cases.
Abstract: Active noise control (ANC) has been widely applied in industry to reduce environmental noise and equipment vibrations. Most available control algorithms require the identification of the secondary path, which increases the control system complexity, contributes to an increased residual noise power, and can even cause the control system to fail if the identified secondary path is not sufficiently close to the actual path. In this paper, based on the geometric analysis and the strict positive real (SPR) property of the filtered-x LMS algorithm, we introduce a new ANC algorithm suitable for single-tone noises as well as some specific narrowband noises that does not require the identification of the secondary path, though its convergence can be very slow in some special cases. We are able to extend the developed ANC algorithm to the case of active control of broadband noises through our use of a subband implementation of the ANC algorithm. Compared to other available control algorithms that do not require secondary path identification, our developed method is simple to implement, yields good performance, and converges quickly. Simulation results confirm the effectiveness of our proposed algorithm
127 citations
TL;DR: In this paper, a locally linear model is used to obtain a trajectory consistent with the dynamics as well as with the measured data, which leads to a significant improvement of correlation dimension estimates.
127 citations
TL;DR: In this article, the effects of noise reduction of six tree belts were examined, where an amplifier was placed in front of each tree belt, while a noise meter was placed at various heights and distances behind the tree belt.
127 citations
TL;DR: The tradeoff that has to be made between noise reduction and interference rejection is theoretically demonstrated and a new relationship between both filters in which the MVDR is decomposed into the LCMV and a matched filter (MVDR solution in the absence of interference).
Abstract: In real-world environments, the signals captured by a set of microphones in a speech communication system are mixtures of the desired signal, interference, and ambient noise. A promising solution for proper speech acquisition (with reduced noise and interference) in this context consists in using the linearly constrained minimum variance (LCMV) beamformer to reject the interference, reduce the overall mixture energy, and preserve the target signal. The minimum variance distortionless response beamformer (MVDR) is also commonly known to reduce the interference-plus-noise energy without distorting the desired signal. In either case, it is of paramount importance to accurately quantify the achieved noise and interference reduction. Indeed, it is quite reasonable to ask, for instance, about the price that has to be paid in order to achieve total removal of the interference without distorting the target signal when using the LCMV. Besides, it is fundamental to understand the effect of the MVDR on both noise and interference. In this correspondence, we investigate the performance of the MVDR and LCMV beamformers when the interference and ambient noise coexist with the target source. We demonstrate a new relationship between both filters in which the MVDR is decomposed into the LCMV and a matched filter (MVDR solution in the absence of interference). Both components are properly weighted to achieve maximum interference-plus-noise reduction. We investigate the performance of the MVDR, LCMV, and matched filters and elaborate new closed-form expressions for their output signal-to-interference ratio (SIR) and output signal-to-noise ratio (SNR). We theoretically demonstrate the tradeoff that has to be made between noise reduction and interference rejection. In fact, the total removal of the interference may severely amplify the residual ambient noise. Conversely, totally focussing on noise reduction leads to increased level of residual interference. The proposed study is finally supported by several numerical examples.
126 citations
TL;DR: In this paper, open-loop noise reduction techniques can be effective in separating partial discharge (PD) signals from noise, through the use of thresholding of wavelet coefficients, which provides near optimal noise reduction for many classes of signals including PD signals in noise.
Abstract: The paper shows that open-loop noise reduction techniques can be effective in separating partial discharge (PD) signals from noise. Wavelet-based denoising through the use of thresholding of wavelet coefficients provides near optimal noise reduction for many classes of signals including PD signals in noise. The effectiveness of wavelet transform-based noise reduction depends on selection of an appropriate wavelet basis function as well as on careful selection of threshold function and levels.
126 citations