John Mourjopoulos

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Single-channel spectral subtraction algorithms are commonly used to suppress late reverberation. A binaural extension of such methods, apart from suppressing reverberation without introducing processing artifacts, should also preserve the signal's binaural localization cues. Here, three state-of-the-art spectral subtraction dereverberation algorithms are(More)
A blind method for suppressing late reverberation from speech and audio signals is presented. The proposed technique operates both on the spectral and on the sub-band domains employing a single input channel. At first, a preliminary rough clean signal estimation is required and for this, any standard technique may be applied; however here the estimate is(More)
A methodology is introduced for smoothing the Complex Transfer Function of measured responses using well-established or arbitrary fractional octave profiles, based on a novel time-frequency, mapping framework. A corresponding impulse response is also analytically derived having reduced complexity but conforming to perceptual principles. The relationship(More)
The performance of recent dereverberation methods for reverberant speech preprocessing prior to Automatic Speech Recognition (ASR) is compared for an extensive range of room and source-receiver configurations. It is shown that room acoustic parameters such as the clarity (C50) and the definition (D50) correlate well with the ASR results. When available,(More)
A method for the estimation of the direct-to-reverberant-ratio (DRR) from dual-channel microphone recordings without having knowledge of the source signal is proposed. The method is based on previous findings for the statistics of the room transfer function spectral standard deviation and its relationship to the DRR. A novel relationship for the standard(More)
A novel method for the estimation of the distance of a sound source from binaural speech signals is proposed. The method relies on several statistical features extracted from such signals and their binaural cues. Firstly, the standard deviation of the difference of the magnitude spectra of the left and right binaural signals is used as a feature for this(More)
Microphone leakage is one of the most prevalent problems in audio applications involving multiple instruments and multiple microphones. Currently, sound engineers have limited solutions available to them. In this paper, the applicability of two widely used signal enhancement methods to this problem is discussed, namely blind source separation and noise(More)