A lightweight speech enhancement network fusing bone- and air-conducted speech

Air-conducted (AC) microphones capture the high-quality desired speech and ambient noise, whereas bone-conducted (BC) microphones are immune to ambient noise but only capture band limited speech. This paper proposes a speech enhancement model that leverages the merits of BC and AC speech. The proposed model takes the spectrogram of BC and AC speech as input and fuses them by an attention-based feature fusion module. The backbone network of the proposed model uses the fused signals to estimate mask of the target speech, which is then applied to the noisy AC speech to recover the target speech. The proposed model adopts a lightweight design of densely gated convolutional attention network (DenGCAN) as the backbone network, which contains encoder, bottleneck layers, and decoder. Furthermore, this paper improves an attention gate and integrates it into skip-connections of DenGCAN, which allows the decoder to focus on the key areas of the feature map extracted by the encoder. As the DenGCAN adopts self-attention mechanism, the proposed model has the potential to improve noise reduction performance at the expense of an increased input-output latency. Experimental results demonstrate that the enhanced speech of the proposed model achieves an average 1.870 wideband-PESQ improvement over the noisy AC speech.