Silent speech recognition (SSR) is an essential task in human–computer interaction, aiming to recognize speech from non-acoustic modalities. A key challenge in SSR is inherent input ambiguity due to partial speech information absence in non-acoustic signals. This ambiguity leads to homophones-words with similar inputs yet different pronunciations. Current approaches address this issue either by utilizing richer additional inputs or training extra models for cross-modal embedding compensation. In this paper, we propose an effective multi-modal co-learning framework promoting the discriminative ability of silent speech representations via multi-stage training. We first construct the backbone of SSR using ultrasound tongue imaging (UTI) as the main modality and then introduce two auxiliary modalities: lip video and audio signals. Utilizing modality dropout, the model learns shared/specific features from all available streams creating a same semantic space for better generalization of the UTI representation. Given cross-modal unbalanced optimization, we highlight the importance of hyperparameter settings and modulation strategies in enabling modality-specific co-learning for SSR. Experimental results show that the modality-agnostic models with single UTI input outperform state-of-the-art modality-specific models. Confusion analysis based on phonemes/articulatory features confirms that co-learned UTI representations contain valuable information for distinguishing homophenes. Additionally, our model can perform well on two unseen testing sets, achieving cross-modal generalization for the uni-modal SSR task.
One-shot voice conversion (VC) has attracted more and more attention due to its broad prospects for practical application. In this task, the representation ability of speech features and the model’s generalization are the focus of attention. This paper proposes a model called CLESSR-VC, which enhances pre-trained self-supervised learning (SSL) representations through contrastive learning for one-shot VC. First, SSL features from the 23rd and 9th layers of the pre-trained WavLM are adopted to extract content embedding and SSL speaker embedding, respectively, to ensure the model’s generalization. Then, the conventional acoustic feature mel-spectrograms and contrastive learning are introduced to enhance the representation ability of speech features. Specifically, contrastive learning combined with the pitch-shift augmentation method is applied to disentangle content information from SSL features accurately. Mel-spectrograms are adopted to extract mel speaker embedding. The AM-Softmax and cross-architecture contrastive learning are applied between SSL and mel speaker embeddings to obtain the fused speaker embedding that helps improve speech quality and speaker similarity. Both objective and subjective evaluation results on the VCTK corpus confirm that the proposed VC model has outstanding performance and few trainable parameters.
Previous audio-visual speech separation methods synchronize the speaker's facial movement and speech in the video to self-supervise the speech separation. In this paper, we propose a model to solve the speech separation problem assisted by both face and sign language, which we call the extended speech separation problem. We design a general deep learning network to learn the combination of three modalities, audio, face, and sign language information, to solve the speech separation problem better. We introduce a large-scale dataset named the Chinese Sign Language News Speech (CSLNSpeech) dataset to train the model, in which three modalities coexist: audio, face, and sign language. Experimental results show that the proposed model performs better and is more robust than the usual audio-visual system. In addition, the sign language modality can also be used alone to supervise speech separation tasks, and introducing sign language helps hearing-impaired people learn and communicate. Last, our model is a general speech separation framework and can achieve very competitive separation performance on two open-source audio-visual datasets. The code is available at https://github.com/iveveive/SLNSpeech