It was recently revealed that using features extracted from pre-trained models can achieve much better performance than using conventional hand-crafted acoustic features for spoofing speech detection. In this paper, we therefore enhance the features from pre-trained model based on recursive learning. Specifically, we modify the pre-trained model by feeding the features from the topmost transformer layer to bottom layers recursively, and the obtained recursive features from the bottom layers are fused with that from topmost layer. The fused features are then fed into the backend classifiers. Experiments are carried out on two benchmark datasets (i.e., ASVspoof 2019 LA and ASVspoof 2021 LA), which show the superiority of the proposed method over state-of-the-art systems.

In this paper, we propose a noise-invariant speaker representation learning (SRL) approach by aligning noisy-clean speech pairs at both the feature and embedding levels for model training. Specifically, we first construct noisy-clean pairs using data augmentation during training. The noisy features are then processed by a Conformer-based enhancement module. The feature-level alignment is achieved by minimizing the mean squared error between the enhanced and original clean data. At the embedding level, we introduce a supervised contrastive learning loss with noise-adaptive margin to simultaneously enhance the intra-speaker compactness and the inter-speaker separability and better adapt different noise levels, in combination with the Barlow Twins self-supervised loss to align the noisy-clean data pairs and reduce noise redundancy in the embedding space. Finally, these loss components are integrated with conventional classification loss to train the SRL network. Experimental results on various VoxCeleb1 test sets synthesized with noise sources demonstrate the effectiveness of the proposed method.

In this paper, a multi-scale feature fusion paradigm is proposed to fully exploit the power of the pre-trained models for text-independent speaker verification. It contains a front-end feature extractor and an enhanced ECAPA-TDNN backend in a cascade manner. The feature extractor incorporates local representations of the CNN layers as well as the global clues of the Transformer layers of the pre-trained models, which are combined to construct the multi-scale discriminative features. The outputs of the feature extractor are then fed into the back-end model (tailored from ECAPA-TDNN) to obtain the final speaker embedding. Results on VoxCeleb datasets validate the superiority of the proposed method with equal error rates of 0.633% and 0.457% on the official trials of Vox1-O using the base and large pre-trained models, respectively.