Chengshi Zheng

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This paper studies the statistical properties of the gain functions, which are often used for two-channel post-filtering (TC-PF) algorithms. We reveal that the smoothing factor has a significant impact on both noise reduction and musical noise. When the smoothing factor increases, noise reduction can be improved and musical noise can be reduced(More)
This paper proposes an adaptive averaging periodogram (AAP) spectral estimator based on the structure of noise power spectral density (NPSD) for speech enhancement, which will be herein referred to as NPSD-AAP. In the proposed spectral estimator, both the raw periodogram and the NPSD are smoothed over frequency to reduce their variances if the NPSD has a(More)
Considering that spectral components of one random process are not necessarily independent for all types of signals, this paper defines a generalized auto-spectral coherence function (GAS-CF) to measure this spectral correlation. The GAS-CF is a generalization of the temporal coherence function and the spectral coherence function, where they have already(More)
This paper derives explicit expressions of the probability density functions of the two-channel post-filter estimators in isotropic noise fields to study their statistical properties. According to the analysis results, three methods are proposed to improve the performance of the noise filed coherence (NFC)-based post-filter estimator.
After revealing that both late reverberation and noise are additive interference components in the residual domain, this paper proposes to suppress these additive interference components by using a constrained minimum mean square error linear prediction (LP) residual estimator, where the optimal filter can be obtained by the generalized singular value(More)
Several seemingly disparate non-parametric magnitude squared coherence (MSC) estimators are treated in a unified way recently. This paper gives a new insight into the non-parametric MSC estimators and points out that the reduced-rank techniques can be applied to the coherence matrix, where the rank is determined by the generalized likelihood ratio test(More)
Most previously proposed dual-channel coherent-to-diffuse-ratio (CDR) estimators are based on a free-field model. When used for binaural signals, e.g., for dereverberation in binaural hearing aids, their performance may degrade due to the influence of the head, even when the direction-of-arrival of the desired speaker is exactly known. In this paper, the(More)
This paper proposes to extend the bandwidth of speech acquired by a system combining laser Doppler vibrometer (LDV) and an auxiliary microphone in adverse environments, where this system is referred to as LDV-AM. Traditional bandwidth extension (BWE) algorithms often need two stages to estimate the broadband spectral envelope. In the first stage, the(More)