Recent Face Anti-Spoofing (FAS) methods have improved generalization to unseen domains by leveraging domain generalization techniques. However, they overlooked the semantic relationships between local features, resulting in suboptimal feature alignment and limited performance. To this end, pixel-wise supervision has been introduced to offer contextual guidance for better feature alignment. Unfortunately, the semantic ambiguity in coarsely designed pixel-wise supervision often leads to misalignment. This paper proposes a novel Dual Consistency Regularization Network (DCRN). It promotes the fine-grained alignment of local features with dense semantic correspondence for FAS. Specifically, a Dual Consistency Learning module (DCL) is devised to capture the inter- and intra-similarity between each region of sample pairs. In this module, a dual consistency regularization learning objective enhances the semantic consistency of local features by minimizing both the variance of inter-similarity and the distance between inter- and intra-similarity. Further, a weight matrix is estimated based on the inter-similarity, representing the possibility that each region belongs to the living class. Based on this weight matrix, WMSE loss is designed to guide the model in avoiding mapping the live regions to the spoofing class, thus alleviating semantic ambiguity in pixel-wise supervision. Extensive experiments on four widely used datasets clearly demonstrate the superiority and high generalization of the proposed DCRN.

Face Anti-Spoofing is critical to secure face recognition systems from presentation attacks. Existing methods often suffer from performance degradation due to image quality issues, such as blurring, overexposure, or varied background, which cause distribution deviations of face images in the quality space, and hinder the learning of effective liveness features. In this paper, we propose a novel method that interactively co-reinforces the liveness and Face Quality representations for Face Anti-Spoofing (FQ-FAS). Specifically, to enhance the discrimination of face quality representation, FQ-FAS first designs a face quality learning module that naturally mitigates the interference from background. Subsequently, a quality-spoofing feature interaction module is devised to co-reinforce both liveness and face quality representations. Meanwhile, we propose a quality aware triplet loss to align the distribution of face images from two aspects: one is to pull the homogeneous face images with different quality together, while the other is to push the inhomogeneous samples with similar quality away in the feature space. In this way, FQ-FAS can learn reliable and discriminative representations for face anti-spoofing. Extensive intra-dataset and cross-dataset experiments clearly demonstrate that our method obtains better performance than previous state-of-the-art methods.

Scale variation is one of the key challenges in the object detection. Most previous object detectors remedy this by using dilated convolution to enlarge the receptive fields of the vanilla convolutional layers. However, these methods focus on either the spatial information of small objects or the semantics of middle and large objects, which still fail to effectively adapt the scale variance of different objects, resulting in a sub-optimal performance for the object detection. In this paper, we propose a novel Multi-Sequence Dilated Network (MSDN) that stacks different dilated convolutions with different orders in parallel for improving the performance of the object detection. Concretely, MSDN contains a sequential dilated module and a dilated attention module. The former aims to generate scale-specific feature maps with fine-spatial and semantic information of objects at different scales, while the latter further selects more powerful information to adaptively enlarge the receptive fields of object features at different scales. Facilitated with these modules, MSDN well obtains the fine-spatial and semantic information of objects at different scales, thus solving the problem of the scale variation. Comprehensive experimental results over two public object detection benchmarks clearly demonstrate the effectiveness of our proposed MSDN. Particularly, on the COCO dataset, the mAP value of MSDN is 48.7%, outperforming existing state-of-the-art methods in a single model manner.

Face anti-spoofing plays a vital role in face recognition systems. The existed deep learning approaches have effectively improved the performance of presentation attack detection (PAD). However, they learn a uniform feature for different types of presentation attacks, which ignore the diversity of the inherent cues presented in different spoofing types. As a result, they can not effectively represent the intrinsic difference between different spoof faces and live faces, and the performance drops on the cross-domain databases. In this paper, we introduce the inherent cues of different spoofing types by non-uniform learning as complements to uniform features. Two lightweight sub-networks are designed to learn inherent motion patterns from photo attacks and the inherent texture cues from video attacks. Furthermore, an element-wise weighting fusion strategy is proposed to integrate the non-uniform inherent cues and uniform features. Extensive experiments on four public databases demonstrate that our approach outperforms the state-of-the-art methods and achieves a superior performance of 3.7% ACER in the cross-domain Protocol 4 of the Oulu-NPU database. Code is available at https://github.com/BJUT-VIP/Non-uniform-cues.