Sensing to Hear through Memory: Ultrasound Speech Enhancement without Real Ultrasound Signals

Speech enhancement on mobile devices is a very challenging task due to the complex environmental noises. Recent works using lip-induced ultrasound signals for speech enhancement open up new possibilities to solve such a problem. However, these multi-modal methods cannot be used in many scenarios where ultrasound-based lip sensing is unreliable or completely absent. In this paper, we propose a novel paradigm that can exploit the prior learned ultrasound knowledge for multi-modal speech enhancement only with the audio input and an additional pre-enrollment speaker embedding. We design a memory network to store the ultrasound memory and learn the interrelationship between the audio and ultrasound modality. During inference, the memory network is able to recall the ultrasound representations from audio input to achieve multi-modal speech enhancement without needing real ultrasound signals. Moreover, we introduce a speaker embedding module to further boost the enhancement performance as well as avoid the degradation of the recalling when the noise level is high. We adopt an end-to-end multi-task manner to train the proposed framework and perform extensive evaluations on the collected dataset. The results show that our method yields comparable performance with audio-ultrasound methods and significantly outperforms the audio-only methods.