The Experts below are selected from a list of 315 Experts worldwide ranked by ideXlab platform
B. Sallberg - One of the best experts on this subject based on the ideXlab platform.
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faster Subband Signal processing dsp tips tricks
IEEE Signal Processing Magazine, 2013Co-Authors: B. SallbergAbstract:Subband Signal processing is an important tool in numerous applications such as acoustic echo cancellation, noise reduction, Signal enhancement, adaptive beam forming, and Signal separation, among other applications. Subband Signal processing uses a filter bank to split each input Signal into a set of frequency Signals, each covering a fraction of the input Signal bandwidth. Subband processing provides an efficient way to divide and conquer tedious problems by a set of parallel and smaller Subband algorithms. In many cases, the Subband processing is performed together with decimation, which reduces the dimensionality of the data in the Subband algorithm. The focus in this article is on temporal Subband processing, i.e., time-frequency transformation, although spatial Subband processing may also gain from the discussion here.
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Faster Subband Signal Processing [dsp Tips&Tricks]
IEEE Signal Processing Magazine, 2013Co-Authors: B. SallbergAbstract:Subband Signal processing is an important tool in numerous applications such as acoustic echo cancellation, noise reduction, Signal enhancement, adaptive beam forming, and Signal separation, among other applications. Subband Signal processing uses a filter bank to split each input Signal into a set of frequency Signals, each covering a fraction of the input Signal bandwidth. Subband processing provides an efficient way to divide and conquer tedious problems by a set of parallel and smaller Subband algorithms. In many cases, the Subband processing is performed together with decimation, which reduces the dimensionality of the data in the Subband algorithm. The focus in this article is on temporal Subband processing, i.e., time-frequency transformation, although spatial Subband processing may also gain from the discussion here.
Daniel Alfsmann - One of the best experts on this subject based on the ideXlab platform.
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oversampling complex modulated digital filter bank pairs suitable for extensive Subband Signal amplification
European Signal Processing Conference, 2009Co-Authors: Thomas Kurbiel, Heinz G Gockler, Daniel AlfsmannAbstract:Oversampling, complex-modulated digital Subband coder filter banks are commonly adopted in modern hearing aids to allow for individual amplification of Subband Signals in order to compensate for hearing losses of impaired persons. Minimum power consumption and low group delay have been the main concern in the design of these filter banks. Guaranteeing frequency-independent and low group delay in case of Subband-Signal amplification has, however, been neglected in the past. In this contribution, we investigate the delay and amplification properties of oversampling complex-modulated FIR filter banks in case of extensive Subband Signal amplification. Based on these results, a sufficient condition for constant group delay is derived. Furthermore, we present a compensation method which allows for constant group delay, even if the sufficient condition is violated. An illustrative design example demonstrates the potential of the compensation method.
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EUSIPCO - Oversampling complex-modulated digital filter bank pairs suitable for extensive Subband-Signal amplification
2009Co-Authors: Thomas Kurbiel, Heinz G Gockler, Daniel AlfsmannAbstract:Oversampling, complex-modulated digital Subband coder filter banks are commonly adopted in modern hearing aids to allow for individual amplification of Subband Signals in order to compensate for hearing losses of impaired persons. Minimum power consumption and low group delay have been the main concern in the design of these filter banks. Guaranteeing frequency-independent and low group delay in case of Subband-Signal amplification has, however, been neglected in the past. In this contribution, we investigate the delay and amplification properties of oversampling complex-modulated FIR filter banks in case of extensive Subband Signal amplification. Based on these results, a sufficient condition for constant group delay is derived. Furthermore, we present a compensation method which allows for constant group delay, even if the sufficient condition is violated. An illustrative design example demonstrates the potential of the compensation method.
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EUSIPCO - Filter banks for hearing aids applying Subband amplification: A comparison of different specification and design approaches
2009Co-Authors: Daniel Alfsmann, Heinz G Gockler, Thomas KurbielAbstract:Hearing instruments employ filter bank systems (FBS) to subdivide the microphone Signal into Subband Signals. To reduce overall computation, decimation is applied, which inevitably induces disturbance. First, these effects are analysed in detail. Then, we postulate application specific FBS requirements in view of extensive Subband Signal amplification. Next, we compare four different prototype filter specification and design approaches for oversampling complex-modulated FBS with respect to the postulated requirements. Finally, we present design examples applying these approaches. Thus, we explicitly demonstrate the impact of Subband Signal amplification on the FBS characteristics.
Rainer Martin - One of the best experts on this subject based on the ideXlab platform.
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estimation of Subband speech correlations for noise reduction via mvdr processing
IEEE Transactions on Audio Speech and Language Processing, 2014Co-Authors: Alexander Schasse, Rainer MartinAbstract:Recently, it has been proposed to use the minimum-variance distortionless-response (MVDR) approach in single-channel speech enhancement in the short-time frequency domain. By applying optimal FIR filters to each Subband Signal, these filters reduce additive noise components with less speech distortion compared to conventional approaches. An important ingredient to these filters is the temporal correlation of the speech Signals. We derive algorithms to provide a blind estimation of this quantity based on a maximum-likelihood and maximum a-posteriori estimation. To derive proper models for the inter-frame correlation of the speech and noise Signals, we investigate their statistics on a large dataset. If the speech correlation is properly estimated, the previously derived Subband filters discussed in this work show significantly less speech distortion compared to conventional noise reduction algorithms. Therefore, the focus of the experimental parts of this work lies on the quality and intelligibility of the processed Signals. To evaluate the performance of the Subband filters in combination with the clean speech inter-frame correlation estimators, we predict the speech quality and intelligibility by objective measures.
Thomas Kurbiel - One of the best experts on this subject based on the ideXlab platform.
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oversampling complex modulated digital filter bank pairs suitable for extensive Subband Signal amplification
European Signal Processing Conference, 2009Co-Authors: Thomas Kurbiel, Heinz G Gockler, Daniel AlfsmannAbstract:Oversampling, complex-modulated digital Subband coder filter banks are commonly adopted in modern hearing aids to allow for individual amplification of Subband Signals in order to compensate for hearing losses of impaired persons. Minimum power consumption and low group delay have been the main concern in the design of these filter banks. Guaranteeing frequency-independent and low group delay in case of Subband-Signal amplification has, however, been neglected in the past. In this contribution, we investigate the delay and amplification properties of oversampling complex-modulated FIR filter banks in case of extensive Subband Signal amplification. Based on these results, a sufficient condition for constant group delay is derived. Furthermore, we present a compensation method which allows for constant group delay, even if the sufficient condition is violated. An illustrative design example demonstrates the potential of the compensation method.
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EUSIPCO - Oversampling complex-modulated digital filter bank pairs suitable for extensive Subband-Signal amplification
2009Co-Authors: Thomas Kurbiel, Heinz G Gockler, Daniel AlfsmannAbstract:Oversampling, complex-modulated digital Subband coder filter banks are commonly adopted in modern hearing aids to allow for individual amplification of Subband Signals in order to compensate for hearing losses of impaired persons. Minimum power consumption and low group delay have been the main concern in the design of these filter banks. Guaranteeing frequency-independent and low group delay in case of Subband-Signal amplification has, however, been neglected in the past. In this contribution, we investigate the delay and amplification properties of oversampling complex-modulated FIR filter banks in case of extensive Subband Signal amplification. Based on these results, a sufficient condition for constant group delay is derived. Furthermore, we present a compensation method which allows for constant group delay, even if the sufficient condition is violated. An illustrative design example demonstrates the potential of the compensation method.
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EUSIPCO - Filter banks for hearing aids applying Subband amplification: A comparison of different specification and design approaches
2009Co-Authors: Daniel Alfsmann, Heinz G Gockler, Thomas KurbielAbstract:Hearing instruments employ filter bank systems (FBS) to subdivide the microphone Signal into Subband Signals. To reduce overall computation, decimation is applied, which inevitably induces disturbance. First, these effects are analysed in detail. Then, we postulate application specific FBS requirements in view of extensive Subband Signal amplification. Next, we compare four different prototype filter specification and design approaches for oversampling complex-modulated FBS with respect to the postulated requirements. Finally, we present design examples applying these approaches. Thus, we explicitly demonstrate the impact of Subband Signal amplification on the FBS characteristics.
Les Atlas - One of the best experts on this subject based on the ideXlab platform.
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time frequency coherent modulation filtering of nonstationary Signals
IEEE Transactions on Signal Processing, 2009Co-Authors: P Clark, Les AtlasAbstract:Modulation filtering is a class of techniques for filtering slowly-varying modulation envelopes of frequency Subbands of a Signal, ideally without affecting the Subband Signal's temporal fine-structure. Coherent modulation filtering is a potentially more effective type of such techniques where, via an explicit product model, Subband envelopes are determined from demodulation of the Subband Signal with a coherently detected Subband carrier. In this paper we propose a coherent modulation filtering technique based on detecting the instantaneous frequency of a Subband from its time-frequency representation. We devise theory to show that coherent modulation filtering imposes a new bandlimiting constraint on the product of the modulator and carrier as well as the ability to recover arbitrarily chosen envelopes and carriers from their modulation product. We then formally show that a carrier estimate based on the time-varying spectral center-of-gravity satisfies the bandlimiting condition. This bandwidth constraint leads to effective and artifact-free modulation filters, offering new approaches for potential Signal modification. However, the spectral center-of-gravity does not, in general, satisfy the condition of arbitrary carrier recovery. Finally, the results from modulation-filtering a speech Signal are then used to validate the theory.
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ICASSP - A sum-of-products model for effective coherent modulation filtering
2009 IEEE International Conference on Acoustics Speech and Signal Processing, 2009Co-Authors: P Clark, Les AtlasAbstract:Modulation filtering is a technique for filtering slowly-varying envelopes of frequency Subbands of a nonstationary Signal, ideally without affecting the Signal's phase and fine-structure. Coherent modulation filtering is a promising subtype of such techniques where Subband envelopes are determined through demodulation of the Subband Signal with a coherently detected Subband carrier. In this paper we demonstrate how modulation filtering, when done coherently, is far more effective than standard incoherent methods. We show that empirical results can be made to be almost ideal, and significantly better than previous coherent attempts, as long as fine-structure information is retained as side information and the filterbank reduces Subband interference.
