Sarmad Malik

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We present a novel recursive Bayesian method in the DFT-domain to address the multichannel acoustic echo cancellation problem. We model the echo paths between the loudspeakers and the near-end microphone as a multichannel random variable with a first-order Markov property. The incorporation of the near-end observation noise, in conjunction with the(More)
In this paper, we address adaptive acoustic echo cancellation in the presence of an unknown memoryless nonlinearity preceding the echo path. We approach the problem by considering a basis-generic expansion of the memoryless nonlinearity. By absorbing the coefficients of the nonlinear expansion into the unknown echo path, the cascade observation model is(More)
We consider the task of acoustic system identification, where the input signal undergoes a memoryless nonlinear transformation before convolving with an unknown linear system. We focus on the possibility of modeling the nonlinearity with different basis functions, namely the established power series and the proposed Fourier expansion. In this work the(More)
A linear dynamical model can be used to describe the evolution of an unknown system in noisy conditions. However, in most applications model parameters of a dynamical system are not known a priori, bringing into question the optimality of traditional state-only estimators. In this paper, we consider block-frequency-domain dynamical models and formulate an(More)
In this work, we present novel Bayesian algorithms for acoustic echo cancellation and residual echo suppression in the presence of a memoryless loudspeaker nonlinearity. The system nonlinearity is modeled using a basis-generic nonlinear expansion. This allows us to express the microphone observation in the DFT domain in terms of the nonlinear-expansion(More)
In this contribution, we present a novel low-complexity state-space algorithm for multichannel acoustic echo cancellation. The reduction in complexity is brought about by means of top-down imposition of mutual independence on the respective acoustic echo paths within a variational Bayesian framework. This results in a fully diagonalized multichannel(More)
Room reverberation and background noise severely degrade the quality of hands-free speech communication systems. In this work, we address the problem of combined speech dereverberation and noise reduction using a variational Bayesian (VB) inference approach. Our method relies on a multichannel state-space model for the acoustic channels that combines(More)
This paper presents an online dereverberation algorithm that is derived within the maximum-likelihood expectation-maximization (ML-EM) framework. We formulate an overlap-save observation model for the multichannel blind problem in the DFT-domain. The modeling of acoustic channel impulse responses as random variables with a first-order Markov property(More)
Scalable fault tolerant Agent Grooming Environment (SAGE) is first open source initiative in South-Asia. It is a multi-agent system which has been developed according to FIPA (Foundation for Intelligent Physical Agents) 2002 specifications. SAGE has been designed with a distributed and decentralized architecture to achieve fault tolerance and scalability as(More)
In this contribution, we present a variational Bayesian framework for the acoustic echo cancellation problem in the presence of a memoryless loudspeaker nonlinearity. We pursue a cascade modeling strategy, where first-order Markov models are described over the acoustic echo path and the nonlinear expansion coefficients. An iterative algorithm is then(More)