3-D CNN Models for Far-Field Multi-Channel Speech Recognition

Automatic speech recognition (ASR) in far-field reverberant environments, especially when involving natural conversational multiparty speech conditions, is challenging even with the state-of-the-art recognition methodologies. The two main issues are artifacts in the signal due to reverberation and the presence of multiple speakers. In this paper, we propose a three dimensional (3-D) convolutional neural network (CNN) architecture for multi-channel far-field ASR. This architecture processes time, frequency & channel dimensions of the input spectrogram to learn representations using convolutional layers. Experiments are performed on the REVERB challenge LVCSR task and the augmented multi-party (AMI) LVCSR task using the array microphone recordings. The proposed method shows improvements over the baseline system that uses beamforming of the multi-channel audio along with a 2-D conventional CNN framework (absolute improvements of 1.1 % over the beamformed baseline system on AMI dataset).