Recent studies on deepfake detection have achieved promising results when training and testing faces are from the same dataset. However, their results severely degrade when confronted with forged samples that the model has not yet seen during training. In this paper, deepfake data to help detect deepfakes. this paper present we put a new insight into diffusion model-based data augmentation, and propose a Masked Conditional Diffusion Model (MCDM) for enhancing deepfake detection. It generates a variety of forged faces from a masked pristine one, encouraging the deepfake detection model to learn generic and robust representations without overfitting to special artifacts. Extensive experiments demonstrate that forgery images generated with our method are of high quality and helpful to improve the performance of deepfake detection models.

Abstract Human actions are predominantly presented in 2D format in video surveillance scenarios, which hinders the accurate determination of action details not apparent in 2D data. Depth estimation can aid human action recognition tasks, enhancing accuracy with neural networks. However, reliance on images for depth estimation requires extensive computational resources and cannot utilise the connectivity between human body structures. Besides, the depth information may not accurately reflect actual depth ranges, necessitating improved reliability. Therefore, a 2D human skeleton action recognition method with spatial constraints (2D‐SCHAR) is introduced. 2D‐SCHAR employs graph convolution networks to process graph‐structured human action skeleton data comprising three parts: depth estimation, spatial transformation, and action recognition. The initial two components, which infer 3D information from 2D human skeleton actions and generate spatial transformation parameters to correct abnormal deviations in action data, support the latter in the model to enhance the accuracy of action recognition. The model is designed in an end‐to‐end, multitasking manner, allowing parameter sharing among these three components to boost performance. The experimental results validate the model's effectiveness and superiority in human skeleton action recognition.

Abstract Visible‐infrared person re‐identification (VI‐ReID) aims to recognize images of the same person captured in different modalities. Existing methods mainly focus on learning single‐granularity representations, which have limited discriminability and weak robustness. This paper proposes a novel dual‐granularity feature fusion network for VI‐ReID. Specifically, a dual‐branch module that extracts global and local features and then fuses them to enhance the representative ability is adopted. Furthermore, an identity‐aware modal discrepancy loss that promotes modality alignment by reducing the gap between features from visible and infrared modalities is proposed. Finally, considering the influence of non‐discriminative information in the modal‐shared features of RGB‐IR, a greyscale conversion is introduced to extract modality‐irrelevant discriminative features better. Extensive experiments on the SYSU‐MM01 and RegDB datasets demonstrate the effectiveness of the framework and superiority over state‐of‐the‐art methods.

Abstract Skeleton‐based neural networks have been considered a focus for human action recognition (HAR). It is noteworthy that the existing skeleton‐based methods are not capable of combining the spatial and temporal features reasonably to derive more effective high‐level representations, and it continues to be a challenging task of learning and representing the skeleton action discriminatively. In this study, a novel two‐stream spatiotemporal network (TSTN) is proposed, which is capable of processing the spatial and temporal features respectively and collectively to achieve a better representation and understanding of human action. The temporal branch stacks three gate recurrent unit (GRU) blocks in a new architecture to encode the temporal correlations from different aspects of human action, achieving high‐level temporal semantic feature expressions. The spatial branch encodes the spatial features with multi‐stacked graph convolutional network (GCN) blocks. Self‐attention mechanisms incorporated with the graph structure of the skeleton are explored to add weight influence and structural hints to further enhance the performance. The experimental results verify the effectiveness and superiority of the proposed model in skeleton action recognition; the model reaches state‐of‐the‐art on specific datasets.

This paper proposes an attention-guided feature disentangling framework (AgFD) to eliminate the large cross-modality discrepancy for Heterogeneous Face Recognition (HFR). Existing HFR methods either focus only on extracting identity features or impose linear/no independence constraints on the decomposed components. Instead, our AgFD disentangles the facial representation and forces intrinsic independence between identity features and identity-irrelevant variations. To this end, an Attention-based Residual Decomposition Module (AbRDM) and an Adversarial Decorrelation Module (ADM) are presented. AbRDM provides hierarchical complementary feature disentanglement, while ADM is introduced for decorrelation learning. Extensive experiments on the challenging CASIA NIR-VIS 2.0 Database, Oulu-CASIA NIR&VIS Database, BUAA-VisNir Database, and IIIT-D Viewed Sketch Database demonstrate the generalization ability and competitive performance of the proposed method.