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 presents a sinusoidal model based algorithm for enhancement of speech degraded by additive broad-band noise that shows considerable improvement over traditional spectral subtraction and Wiener filtering based schemes.
Abstract: This paper presents a sinusoidal model based algorithm for enhancement of speech degraded by additive broad-band noise. In order to ensure speech-like characteristics observed in clean speech, smoothness constraints are imposed on the model parameters using a spectral envelope surface (SES) smoothing procedure. Algorithm evaluation is performed using speech signals degraded by additive white Gaussian noise. Distortion as measured by objective speech quality scores showed a 34%-41% reduction over a SNR range of 5-to-20 dB. Objective and subjective evaluations also show considerable improvement over traditional spectral subtraction and Wiener filtering based schemes. Finally, in a subjective AB preference test, where enhanced signals were coded with the G729 codec, the proposed scheme was preferred over the traditional enhancement schemes tested for SNRs in the range of 5 to 20 dB.
125 citations
TL;DR: Simulation results show that the VMD- DWT approach outperforms the conventional EMD-DWT approach, and a non-local means approach used as a reference technique provides better results than the V MD-D WT approach.
Abstract: Hybrid denoising models based on combining empirical mode decomposition (EMD) and discrete wavelet transform (DWT) were found to be effective in removing additive Gaussian noise from electrocardiogram (ECG) signals. Recently, variational mode decomposition (VMD) has been proposed as a multiresolution technique that overcomes some of the limits of the EMD. Two ECG denoising approaches are compared. The first is based on denoising in the EMD domain by DWT thresholding, whereas the second is based on noise reduction in the VMD domain by DWT thresholding. Using signal-to-noise ratio and mean of squared errors as performance measures, simulation results show that the VMD-DWT approach outperforms the conventional EMD-DWT. In addition, a non-local means approach used as a reference technique provides better results than the VMD-DWT approach.
124 citations
TL;DR: The main aim is to modify the wavelet coefficients in the new basis, the noise can be removed from the data and a signal to noise ratio as a measure of the quality of denoising was preferred.
Abstract: This paper proposes different approaches of wavelet based image denoising methods. The search for efficient image denoising methods is still a valid challenge at the crossing of functional analysis and statistics. In spite of the sophistication of the recently proposed methods, most algorithms have not yet attained a desirable level of applicability. Wavelet algorithms are useful tool for signal processing such as image compression and denoising. Multi wavelets can be considered as an extension of scalar wavelets. The main aim is to modify the wavelet coefficients in the new basis, the noise can be removed from the data. In this paper, we extend the existing technique and providing a comprehensive evaluation of the proposed method. Results based on different noise, such as Gaussian, Poisson's, Salt and Pepper, and Speckle performed in this paper. A signal to noise ratio as a measure of the quality of denoising was preferred.
124 citations
TL;DR: In this paper, the effects of frequency shift averaging on fading noise reduction are clarified theoretically, and the relationships between measurement accuracy and other parameters, such as spatial resolution and frequency variation range, are derived.
Abstract: The characteristics of fading noise in Rayleigh backscattering measurements made with coherent lightwaves such as in coherent-OTDR (optical time-domain reflectometry) and coherent-OFDR (optical frequency-domain reflectometry) are studied. The effects of frequency shift averaging on fading noise reduction are clarified theoretically, and the relationships between measurement accuracy and other parameters, such as spatial resolution and frequency variation range are derived. The calculated results of loss measurement accuracy are in good agreement with experimental data. The formula can also be applied to low-coherence interferometric OTDR. >
124 citations
TL;DR: In this article, the performance of a noise reduction strategy applied to cochlear implants is evaluated, based on a 2-channel adaptive filtering strategy using two microphones in a single behind-the-ear hearing aid.
Abstract: ObjectiveIn this study the performance of a noise reduction strategy applied to cochlear implants is evaluated. The noise reduction strategy is based on a 2-channel adaptive filtering strategy using two microphones in a single behind-the-ear hearing aid.DesignFour adult LAURA cochlear implant users
124 citations