Browsing by Author "Yang, Chia-Hsin"

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An investigation of time delay estimation in room acoustic environment using magnitude ratio
(2010-01-01)
Hu, Jwu-Sheng
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Yang, Chia-Hsin
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Liu, Wei-Han
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電控工程研究所
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Institute of Electrical and Control Engineering
This paper investigates the relation between the nonstationary sound source and the frequency domain magnitude ratio of two microphones based on short-term frequency analysis. The fluctuation level of nonstationary sound sources is modeled by the exponent of polynomials from the concept of moving pole model. According to this model, the sufficient condition for utilizing the fluctuation level and magnitude ratio to estimate the time delay between two microphones is suggested. Simulation results are presented to show the performance of the suggested method. (C) 2009 Elsevier B.V. All rights reserved.
Estimation of Sound Source Number and Directions under a Multisource Reverberant Environment
(2010)
Hu, Jwu-Sheng
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Yang, Chia-Hsin
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電控工程研究所
;
Institute of Electrical and Control Engineering
Sound source localization is an important feature in robot audition. This work proposes a sound source number and directions estimation method under a multisource reverberant environment. An eigenstructure-based generalized cross-correlation method is proposed to estimate time delay among microphones. A source is considered as a candidate if the corresponding time delay combination among microphones gives reasonable sound speed estimation. Under reverberation, some candidates might be spurious but their direction estimations are not consistent for consecutive data frames. Therefore, an adaptive K-means++ algorithm is proposed to cluster the accumulated results from the sound speed selection mechanism. Experimental results demonstrate the performance of the proposed algorithm in a real room.
Robust Adaptive Beamformer for Speech Enhancement Using the Second-Order Extended H-infinity Filter
(2013-01-01)
Hu, Jwu-Sheng
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Lee, Ming-Tang
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Yang, Chia-Hsin
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應用數學系
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電機工程學系
This paper presents a novel approach to implement the robust minimum variance distortionless response (MVDR) beamformer. The robust MVDR beamformer is based on the optimization of worst-case performance and provides an excellent robustness against an arbitrary but norm-bounded desired signal steering vector mismatch. For real-time consideration, the beamformer was formulated into state-space observer form and the second-order extended (SOE) Kalman filter was derived. However, the SOE Kalman filter assumes an accurate system dynamic and statistics of the noise signals. These assumptions limit the performance under uncertainties. This paper develops the SOE H-infinity filter for the implementation of the robust MVDR beamformer. The estimation criterion in the SOE H-infinity filter design is to minimize the worst possible effects of the disturbance signals on the signal estimation errors without a prior knowledge of the disturbance signals statistics. Experimental results demonstrate the performance of the proposed algorithm in a noisy and reverberant environment and show its superiority of the robustness against mismatches over the robust MVDR beamformer based on the SOE Kalman filter.