TY - CONF AB - In recent years time domain speech separation has excelled over frequency domain separation in single channel scenarios and noise-free environments. In this paper we dissect the gains of the time-domain audio separation network (TasNet) approach by gradually replacing components of an utterance-level permutation invariant training (u-PIT) based separation system in the frequency domain until the TasNet system is reached, thus blending components of frequency domain approaches with those of time domain approaches. Some of the intermediate variants achieve comparable signal-to-distortion ratio (SDR) gains to TasNet, but retain the advantage of frequency domain processing: compatibility with classic signal processing tools such as frequency-domain beamforming and the human interpretability of the masks. Furthermore, we show that the scale invariant signal-to-distortion ratio (si-SDR) criterion used as loss function in TasNet is related to a logarithmic mean square error criterion and that it is this criterion which contributes most reliable to the performance advantage of TasNet. Finally, we critically assess which gains in a noise-free single channel environment generalize to more realistic reverberant conditions. AU - Heitkaemper, Jens AU - Jakobeit, Darius AU - Boeddeker, Christoph AU - Drude, Lukas AU - Haeb-Umbach, Reinhold ID - 20504 KW - voice activity detection KW - speech activity detection KW - neural network KW - statistical speech processing T2 - ICASSP 2020 Virtual Barcelona Spain TI - Demystifying TasNet: A Dissecting Approach ER - TY - CONF AB - Speech activity detection (SAD), which often rests on the fact that the noise is "more'' stationary than speech, is particularly challenging in non-stationary environments, because the time variance of the acoustic scene makes it difficult to discriminate speech from noise. We propose two approaches to SAD, where one is based on statistical signal processing, while the other utilizes neural networks. The former employs sophisticated signal processing to track the noise and speech energies and is meant to support the case for a resource efficient, unsupervised signal processing approach. The latter introduces a recurrent network layer that operates on short segments of the input speech to do temporal smoothing in the presence of non-stationary noise. The systems are tested on the Fearless Steps challenge database, which consists of the transmission data from the Apollo-11 space mission. The statistical SAD achieves comparable detection performance to earlier proposed neural network based SADs, while the neural network based approach leads to a decision cost function of 1.07% on the evaluation set of the 2020 Fearless Steps Challenge, which sets a new state of the art. AU - Heitkaemper, Jens AU - Schmalenstroeer, Joerg AU - Haeb-Umbach, Reinhold ID - 20505 KW - voice activity detection KW - speech activity detection KW - neural network KW - statistical speech processing T2 - INTERSPEECH 2020 Virtual Shanghai China TI - Statistical and Neural Network Based Speech Activity Detection in Non-Stationary Acoustic Environments ER -