A flow-based neural network for time domain speech enhancement

Martin Strauss and Bernd Edler

published at the IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP), 2021

Abstract

Speech enhancement involves the distinction of a target speech signal from an intrusive background. Although generative approaches using Variational Autoencoders or Generative Adversarial Networks (GANs) have increasingly been used in recent years, normalizing flow (NF) based systems are still scarse, despite their success in related fields. Thus, in this paper we propose a NF framework to directly model the enhancement process by density estimation of clean speech utterances conditioned on their noisy counterpart. The WaveGlow model from speech synthesis is adapted to enable direct enhancement of noisy utterances in time domain. In addition, we demonstrate that nonlinear input companding helps to improve the model performance by expanding the range of learnable values. Experimental evaluation on a publicly available dataset shows comparable results to current state-of-the-art GAN-based approaches, while surpassing the chosen baselines using objective evaluation metrics.

Examples

Listening examples from the testset published by Valentini et al. [1]. The dataset can be downloaded here. There are three examples per SNR level and test speaker. In addition, samples from the SEGAN [2] model were added for comparison. The code to create the SEGAN samples can be found here.

ID Gender Noise SNR [dB] Website
p232_005 male Bus 2.5 Link
p232_380 male Bus 12.5 Link
p232_062 male Public square 12.5 Link
p232_034 male Living room 12.5 Link
p232_081 male Public square 17.5 Link
p232_097 male Office 17.5 Link
p232_234 male Public square 2.5 Link
p232_253 male Public square 7.5 Link
p232_219 male Cafè 7.5 Link
p232_282 male Cafè 7.5 Link
p232_284 male Living room 17.5 Link
p232_225 male Office 2.5 Link
p257_040 female Public square 12.5 Link
p257_395 female Living room 2.5 Link
p257_091 female Living room 17.5 Link
p257_130 female Cafè 2.5 Link
p257_081 female Public square 7.5 Link
p257_177 female Office 12.5 Link
p257_233 female Living room 12.5 Link
p257_323 female Public square 2.5 Link
p257_368 female Cafè 17.5 Link
p257_041 female Public square 7.5 Link
p257_218 female Office 7.5 Link
p257_384 female Bus 17.5 Link

References

[1] C. Valentini-Botinhao, X. Wang, S. Takaki, and J. Yamagishi, “Speech enhancement for a noise-robust text-to-speech synthe-sis system using deep recurrent neural networks,” in Proceedings Interspeech Conference, 2016, pp. 352–356.

[2] S. Pascual, A. Bonafonte, and J. Serrà, “SEGAN: Speech Enhancement Generative Adversarial Network,” in Proceedings Interspeech Conference, 2017, pp. 3642–3646.