adaptivealgorithms are used in digital signal processing to reduce noise in audio. adaptive filters play an important role in implementing the idea of adaptivealgorithms. The aim of this thesis is to explore the app...
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ISBN:
(纸本)9798400708299
adaptivealgorithms are used in digital signal processing to reduce noise in audio. adaptive filters play an important role in implementing the idea of adaptivealgorithms. The aim of this thesis is to explore the application and performance comparison of adaptive filtering algorithms in audio signal processing through MATLAB simulation analysis. Through two different application scenarios, including audio white noise cancellation and single-frequency white noise cancellation, this paper demonstrates the efficacy of LMS, NLMS, and RLS algorithms in noise cancellation tasks. Meanwhile, the update curves of the filter parameters under different step sizes and the update curves of the filter weights of LMS, NLMS and RLS algorithms under the same step size are compared. When the step sizes of the LMS algorithm and the NLMS algorithm are 0.001 and 0.01, respectively, and the weights of the RLS algorithm are set to 0.99, and the number of filter orders are set to 20, the three algorithms deal with the single-frequency white noise cancellation more stably. The RLS algorithm converges faster the signal is more stable.
Numerous adaptive filtering algorithms have been proposed for acoustic echo cancellation. However, whether the performance of the algorithms approaches the optimal performance or if there has been intentionally overst...
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Numerous adaptive filtering algorithms have been proposed for acoustic echo cancellation. However, whether the performance of the algorithms approaches the optimal performance or if there has been intentionally overstated remains challenging to evaluate. Fortunately, the Cramér–Rao Lower Bound (CRLB) provides a theoretical minimum variance for any unbiased estimator under given observational data and statistical models. This paper derives the CRLB of adaptive filtering algorithms for acoustic echo cancellation (AEC), in which the generalized Gaussian distribution (GGD) is utilized to model the Gaussian/non-Gaussian background noises. To accelerate the CRLB calculation process, the recursive resolution of the CRLB is presented by using the matrix inversion lemma, and the computational complexity is also analyzed. The derivation results indicate that CRLB for AEC model depends on the acoustic input (i.e., speaker’s voice) and the statistical properties of GGD noise but is unaffected by the channel sparsity. The CRLB derived in this paper can serve as a benchmark to evaluate whether the performance of the adaptive filtering algorithms is optimal and to exclude some adaptive filtering algorithms that deliberately exaggerate their performance.
An adaptive finite impulse response (FIR) filter is a key technique to remove noise in non-stationary signals. With the rapid development of the various adaptivealgorithms, it is both urgent and challenging to compre...
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An adaptive finite impulse response (FIR) filter is a key technique to remove noise in non-stationary signals. With the rapid development of the various adaptivealgorithms, it is both urgent and challenging to comprehensively review the relevant studies. Therefore, this paper thoroughly examined adaptive filters for the existing literature related to adaptivefiltering in noise cancellation. The adaptive filter provides a superior approach for the suppression of noise from non-stationary signals. Although there already exist some valuable surveys on adaptive filters, they do not provide a systematic overview of the challenges faced by adaptive filters and lack a careful distinction and comparison of the various adaptive filter techniques in noise cancellation in non-stationary signals. Three key aspects, namely the challenges faced by adaptive filters, the evolutionary paths involved in the adaptive filter algorithm, and the specific application tasks are discussed in detail. Further, the MATLAB simulations have been carried out to evaluate the filtering performance of the adaptive filter.
In this study, we focus on an adaptivefiltering algorithm that utilizes variable step-size and incorporates graph filter models within the realm of graph signal processing. The algorithm optimizes the step-size by mi...
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In this study, we focus on an adaptivefiltering algorithm that utilizes variable step-size and incorporates graph filter models within the realm of graph signal processing. The algorithm optimizes the step-size by minimizing the energy of the noise-free a posteriori error signal. To extract this noise-free signal from its noisy counterpart, we employ a shrinkage method. Through simulations involving zero-mean i.i.d. Gaussian input signals on a sensor network graph, we demonstrate that our graph-constrained shrinkage least-mean squares (GC-SHLMS) algorithm significantly outperforms traditional algorithms. Specifically, it excels in terms of both convergence speed and steady-state misalignment when compared to the centralized graph-LMS algorithm (GCLMS), the conventional variable-step-size graph-LMS algorithm (GVSSLMS) and the diffusion graph-LMS algorithm (GDLMS).
Two robust affine projection sign (RAPS) algorithms, both of which minimize the mixed norm of l(1) and l(2) of the error signal, are proposed. The direction vector of the RAPS algorithms is obtained from the gradient ...
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Two robust affine projection sign (RAPS) algorithms, both of which minimize the mixed norm of l(1) and l(2) of the error signal, are proposed. The direction vector of the RAPS algorithms is obtained from the gradient of an l(1) norm-based objective function, while two related l(2) norm-based minimization problems are solved to obtain the line search of the two RAPS algorithms. The l(1) norm-based direction vector reduces the impact of impulsive noise, whereas the l(2) norm-based line search produces an unbiased solution in the proposed algorithms. In addition, one of the two RAPS algorithms shares the data selective adaptation used in the set-membership (SM) affine projection (SMAP) algorithm. The proposed algorithms are shown to offer a significant improvement in the convergence speed as well as a significant reduction in the steady-state misalignment relative to the pseudo affine projection sign (PAPS) algorithm. In addition, the proposed algorithms offer robust performance with respect to impulsive noise and improved tracking of the unknown system in comparison to that provided by the PAPS and Affine projection sign (APS) algorithms. These features of the proposed algorithms are demonstrated using simulation results in system-identification and echo-cancellation applications.
Accurate predictions of glucose concentrations are necessary to develop an artificial pancreas (AP) system for people with type 1 diabetes (T1D). In this work, a novel glucose forecasting paradigm based on a model fus...
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Accurate predictions of glucose concentrations are necessary to develop an artificial pancreas (AP) system for people with type 1 diabetes (T1D). In this work, a novel glucose forecasting paradigm based on a model fusion strategy is developed to accurately characterize the variability and transient dynamics of glycemic measurements. To this end, four different adaptive filters and a fusion mechanism are proposed for use in the online prediction of future glucose trajectories. The filter fusion mechanism is developed based on various prediction performance indexes to guide the overall output of the forecasting paradigm. The efficiency of the proposed model fusion based forecasting method is evaluated using simulated and clinical datasets, and the results demonstrate the capability and prediction accuracy of the data-based fusion filters, especially in the case of limited data availability. The model fusion framework may be used in the development of an AP system for glucose regulation in patients with T1D. (C) 2017 Elsevier Ltd. All rights reserved.
In general, theoretical analyses of adaptive filtering algorithms employ statistical approximations in order to render the derivations tractable. Among such hypotheses, the statistical independence between the current...
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In general, theoretical analyses of adaptive filtering algorithms employ statistical approximations in order to render the derivations tractable. Among such hypotheses, the statistical independence between the current adaptive coefficients and past input vectors is a very popular one. Unfortunately, this simplification gives rise to discrepancies with respect to empirical results, especially for large values of the step-size parameter. In this Letter, this issue is overcome by the usage of an exact expectation analysis (i.e. a stochastic model that does not employ the above-mentioned independence assumption) of the least-mean-squares adaptive algorithm. The authors analysis is also generalised in order to address the common case of coloured additive noise, an issue that is so far missing from the literature. The accuracy of the advanced model is verified through simulations.
An efficient variable step-size diffusion normalised least-mean-square algorithm is proposed via a mean-square deviation (MSD) analysis for the distributed estimation. The proposed algorithm has two distinguishing fea...
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An efficient variable step-size diffusion normalised least-mean-square algorithm is proposed via a mean-square deviation (MSD) analysis for the distributed estimation. The proposed algorithm has two distinguishing features for computational efficiency. In the adaptation step, an intermittent adaptation rule that dynamically adjusts an update interval is proposed to reduce the redundant updates. In the diffusion step, instead of the existing combination rules, a selection rule is proposed to select the intermediate estimate of the most reliable node among its neighbour nodes for the estimate at each node. Moreover, to achieve both fast convergence rate and low steady-state error, a variable step size is obtained by minimising the MSD.
A novel approach to fetal ECG signal recovery using a single abdominal record is proposed. Following transforming the original ECG waveform into a 2D array, we apply an image denoising procedure based on sparse repres...
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ISBN:
(纸本)9781457702013
A novel approach to fetal ECG signal recovery using a single abdominal record is proposed. Following transforming the original ECG waveform into a 2D array, we apply an image denoising procedure based on sparse representations over overcomplete dictionaries obtained by the K-SVD algorithm. A modified version of this algorithm using an L-1-norm fidelity term is shown to improve the performances over the classical L-2-norm approach. Experimental results indicate that the quality of the recovered fetal ECG signals is comparable to those employing multi-channel recordings and Independent Components Analysis or adaptive filtering algorithms.
The standard conjugate gradient (CG) method uses orthogonality of the residues to simplify the formulas for the parameters necessary for convergence. In adaptivefiltering, the sample-by-sample update of the correlati...
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The standard conjugate gradient (CG) method uses orthogonality of the residues to simplify the formulas for the parameters necessary for convergence. In adaptivefiltering, the sample-by-sample update of the correlation matrix and the cross-correlation vector causes a loss of the residue orthogonality in a modified online algorithm, which, in turn, results in loss of convergence and an increase of the filter quadratic mean error. This letter extends a recently proposed control Liapunov function analysis of the CG method viewed as a dynamic system in the standard feedback configuration to the case of adaptivefiltering.
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