Neural FCASA

Neural Blind Source Separation and Diarization for Distant Speech Recognition

Yoshiaki Bando, Tomohiko Nakamura, Shinji Watanabe

Fig. 1: The overview of our joint separation and diarization.

Fig. 1: The overview of our joint separation and diarization.

Abstract: This paper presents a neural method for distant speech recognition (DSR) that jointly separates and diarizes speech mixtures without supervision by isolated signals. A standard separation method for multi-talker DSR is a statistical multichannel method called guided source separation (GSS). While GSS does not require signal-level supervision, it relies on speaker diarization results to handle unknown numbers of active speakers. To overcome this limitation, we introduce and train a neural inference model in a weakly-supervised manner, employing the objective function of a statistical separation method. This training requires only multichannel mixtures and their temporal annotations of speaker activities. In contrast to GSS, once trained, the model can jointly separate and diarize speech mixtures without any auxiliary information. The experimental results with the AMI corpus show that our method outperforms GSS with oracle diarization results regarding word error rates.

Source code: Training and inference scripts with a pre-trained model are available on https://github.com/b-sigpro/neural-fcasa.

Separation and diarization results for English and Japanese conversations

We demonstrate that our model trained on the AMI English corpus can work robustly even for the out-of-domain condition of Japanese conversations.

Demo 1: Separation of an English conversation
Demo 2: Separation of a Japanese conversation

Separation and diarization results for mixtures in the AMI corpus

We show the separation and diarization results for the mixtures in the eval set of the AMI corpus.

Note that these signals are different from those used for the WER evaluation in the paper. The WER was calculated for crops of mixture signals, each having a minimum length of 10 seconds and a target utterance at its center.

ES2004c (650s ~ 660s)
Mixture & annotated speaker activities
GSS
cACGMM
FastMNMF2
WS Neural FCA
Neural FCA + VAD
Neural FCASA
EN2002c (2500s ~ 2510s)
Mixture & annotated speaker activities
GSS
cACGMM
FastMNMF2
WS Neural FCA
Neural FCA + VAD
Neural FCASA