Engineering Commons^™

Speech Enhancement Using Bayesian Estimators Of The Perceptually-Motivated Short-Time Spectral Amplitude (Stsa) With Chi Speech Priors, Marek B. Trawicki, Michael T. Johnson

Electrical and Computer Engineering Faculty Research and Publications

In this paper, the authors propose new perceptually-motivated Weighted Euclidean (WE) and Weighted Cosh (WCOSH) estimators that utilize more appropriate Chi statistical models for the speech prior with Gaussian statistical models for the noise likelihood. Whereas the perceptually-motivated WE and WCOSH cost functions emphasized spectral valleys rather than spectral peaks (formants) and indirectly accounted for auditory masking effects, the incorporation of the Chi distribution statistical models demonstrated distinct improvement over the Rayleigh statistical models for the speech prior. The estimators incorporate both weighting law and shape parameters on the cost functions and distributions. Performance is evaluated in terms of the …

Distributed Multichannel Speech Enhancement With Minimum Mean-Square Error Short-Time Spectral Amplitude, Log-Spectral Amplitude, And Spectral Phase Estimation, Marek B. Trawicki, Michael T. Johnson

Electrical and Computer Engineering Faculty Research and Publications

In this paper, the authors present optimal multichannel frequency domain estimators for minimum mean-square error (MMSE) short-time spectral amplitude (STSA), log-spectral amplitude (LSA), and spectral phase estimation in a widely distributed microphone configuration. The estimators utilize Rayleigh and Gaussian statistical models for the speech prior and noise likelihood with a diffuse noise field for the surrounding environment. Based on the Signal-to-Noise Ratio (SNR) and Segmental Signal-to-Noise Ratio (SSNR) along with the Log-Likelihood Ratio (LLR) and Perceptual Evaluation of Speech Quality (PESQ) as objective metrics, the multichannel LSA estimator decreases background noise and speech distortion and increases speech quality compared to …

Optimal Distributed Microphone Phase Estimation, Marek B. Trawicki, Michael T. Johnson

Dr. Dolittle Project: A Framework for Classification and Understanding of Animal Vocalizations

This paper presents a minimum mean-square error spectral phase estimator for speech enhancement in the distributed multiple microphone scenario. The estimator uses Gaussian models for both the speech and noise priors under the assumption of a diffuse incoherent noise field representing ambient noise in a widely dispersed microphone configuration. Experiments demonstrate significant benefits of using the optimal multichannel phase estimator as compared to the noisy phase of a reference channel.

An Improved Snr Estimator For Speech Enhancement, Yao Ren, Michael T. Johnson

Dr. Dolittle Project: A Framework for Classification and Understanding of Animal Vocalizations

In this paper, we propose an MMSE a priori SNR estimator for speech enhancement. This estimator has similar benefits to the well-known decision-directed approach, but does not require an ad-hoc weighting factor to balance the past a priori SNR and current ML SNR estimate with smoothing across frames. Performance is evaluated in terms of estimation error and segmental SNR using the standard logSTSA speech enhancement method. Experimental results show that, in contrast with the decision-directed estimator and ML estimator, the proposed SNR estimator can help enhancement algorithms preserve more weak speech information and efficiently suppress musical noise.

Condition Monitoring Of Squirrel-Cage Induction Motors Fed By Pwm-Based Drives Using A Parameter Estimation Approach, Behrooz Mirafzal, F. Fateh, Chia-Chou Yeh, Richard J. Povinelli, Nabeel Demerdash

Electrical and Computer Engineering Faculty Research and Publications

Abstract:

A rotor condition monitoring technique is presented in this paper based on a parameter estimation approach. In this technique, the stator currents, voltages and motor speed are used as the input signals, where the outputs will be the rotor's inductance, resistance and consequently rotor time constant. This approach is verified by simulation of two different induction motor cases. These simulations are buttressed by experimental data obtained for a 2-hp induction motor in the case of healthy as well as one, three and five rotor bar breakages. In these tests, the induction motor was energized from a PWM-based drive, in …