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This paper considers techniques for single-channel speech enhancement based on the discrete Fourier transform (DFT). Specifically, we derive minimum mean-square error (MMSE) estimators of speech DFT coefficient magnitudes as well as of complex-valued DFT coefficients based on two classes of generalized gamma distributions, under an additive Gaussian noise(More)
Commonly used spectral amplitude estimators, such as those proposed by Ephraim and Malah, are only optimal when the statistical model is correct and the speech and noise spectral variances are known. In practice, the spectral variances have to be estimated. A simple analysis of the “decision-directed” approach for speech spectral variance(More)
This paper considers estimation of the noise spectral variance from speech signals contaminated by highly nonstationary noise sources. The method can accurately track fast changes in noise power level (up to about 10 dB/s). In each time frame, for each frequency bin, the noise variance estimate is updated recursively with the minimum mean-square error(More)
—Conventionally, the energy of analysis frames is not taken into account for linear prediction (LPC) interpolation. Incorporating the frame energy improves the subjective quality of interpolation, but increases the spectral distortion (SD). The main reason for this discrepancy is that the outliers are increased in low energy parts of segments with rapid(More)
We consider estimation of the noise spectral variance from speech signals contaminated by highly nonstationary noise sources. In each time frame, for each frequency bin, the noise variance estimate is updated recursively with the minimum mean-square error (MMSE) estimate of the current noise power. For the estimation of the noise power, a spectral gain(More)
We consider single-channel blind late-reverberation suppression in noisy and time-varying acoustical environments. Existing estimators for the late reverberant spectral variance (LRSV) are derived assuming the room impulse responses (RIRs) to be time-invariant realizations of a stochastic process. In this paper, we go one step further and analyze(More)
The combination of radar and radiometer for the retrieval of cloud liquid water profiles is investigated. As the basis for the retrievals we use a profile algorithm similar to the one proposed by Peter and Kämpfer [1], but modified on a few points. The radar is used to provide the algorithm with cloud heights and the shape of liquid water profile.(More)
In 1996 and 1998, measurement campaigns have taken place in the Netherlands and the United Kingdom, respectively. A variety of collocated instruments performed measurements on the clouds. Among the instruments were a microwave radiometer, lidars and radars. Also, particle size measuring probes were operated during flights through the clouds. Estimates of(More)