Multi-frame human pose estimation has long been an appealing and fundamental issue in visual perception. Owing to the frequent rapid motion and pose occlusion in videos, this task is extremely challenging. Current state-of-the-art methods seek to model spatiotemporal features by equally fusing each frame in the local sequence, which weakens the target frame information. In addition, existing approaches usually emphasize more on deep features while ignoring the detailed information implied in the shallow feature maps, resulting in the dropping of crucial features. To address the above problems, we propose an effective framework, namely spatiotemporal learning transformer for video-based human pose estimation (SLT-Pose), which consists of a Personalized Feature Extraction Module (PFEM), Self-feature Refinement Module (SRM), Cross-frame Temporal Learning Module (CTLM) and Disentangled Keypoint Detector (DKD). To be specific, we propose PFEM which extracts and modulates the individual frame features to adapt to the varying human shape, and integrates single-frame features to obtain the spatiotemporal features. We further present SRM to establish global correlation spatial cues on the target frame to attain the refinement feature. Then, a CTLM is designed to search for the information most closely related to the target frame from the spatiotemporal features to intensify the interaction between the target frame and the local sequence, using both the shallow detailed and the deep semantic representations. Finally, we employ DKD to extract the disentangled characteristics of each joint and encode the articulated joint pairs in the human body, promoting the model to reasonably and accurately predict the keypoint heatmaps. Extensive experiments on three huamn motion benchmarks, including PoseTrack2017, PoseTrack2018, and Sub-JHMDB dataset, demonstrate that SLT-Pose plays favorably against state-of-the-art approaches in terms of both objective evaluation and subjective visual performance.
Due to the complexity of medical imaging techniques and the high heterogeneity of glioma surfaces, image segmentation of human gliomas is one of the most challenging tasks in medical image analysis. Current methods based on convolutional neural networks concentrate on feature extraction while ignoring the correlation between local and global. In this paper, we propose a residual mix transformer fusion net, namely RMTF-Net, for brain tumor segmentation. In the feature encoder, a residual mix transformer encoder including a mix transformer and a residual convolutional neural network (RCNN) is proposed. The mix transformer gives an overlapping patch embedding mechanism to cope with the loss of patch boundary information. Moreover, a parallel fusion strategy based on RCNN is utilized to obtain local–global balanced information. In the feature decoder, a global feature integration (GFI) module is applied, which can enrich the context with the global attention feature. Extensive experiments on brain tumor segmentation from LGG, BraTS2019 and BraTS2020 demonstrated that our proposed RMTF-Net is superior to existing state-of-art methods in subjective visual performance and objective evaluation.
Accurate medical image segmentation continues to pose significant challenges, as existing methods often struggle to concurrently achieve efficient global context modeling, precise boundary delineation, and robust generalization. To address these issues, a novel framework named Contextual and Frequency-Guided Mamba Network (CFG-MambaNet) is presented. Specifically, a variable-scale state space block based on Mamba is employed so that long-range dependencies can be captured with linear complexity, efficiently addressing the inefficiency of Transformer-based models in high-resolution medical imaging. Moreover, a frequency-guided representation module is incorporated to explicitly separate global low-frequency structures from high-frequency boundary details, which significantly alleviates the difficulty of segmenting lesions with blurred contours or weak textures. Furthermore, an adaptive context aggregation mechanism is introduced to integrate heterogeneous semantic cues and to consistently highlight clinically critical regions, substantially improving robustness across diverse anatomical scales and morphologies. To further stabilize training and improve boundary adherence, a composite loss combined with deep supervision is employed. Extensive experiments were conducted on four publicly available datasets, including ACDC, Kvasir-SEG, ISIC, and SEED, covering cardiac MRI, endoscopy, dermoscopy, and pathology images.
Distinguishing identity-unrelated background information from discriminative identity information poses a challenge in unsupervised vehicle re-identification (Re-ID). Re-ID models suffer from varying degrees of background interference caused by continuous scene variations. The recently proposed segment anything model (SAM) has demonstrated exceptional performance in zero-shot segmentation tasks. The combination of SAM and vehicle Re-ID models can achieve efficient separation of vehicle identity and background information. This paper proposes a method that combines SAM-driven mask autoencoder (MAE) pre-training and background-aware meta-learning for unsupervised vehicle Re-ID. The method consists of three sub-modules. First, the segmentation capacity of SAM is utilized to separate the vehicle identity region from the background. SAM cannot be robustly employed in exceptional situations, such as those with ambiguity or occlusion. Thus, in vehicle Re-ID downstream tasks, a spatially-constrained vehicle background segmentation method is presented to obtain accurate background segmentation results. Second, SAM-driven MAE pre-training utilizes the aforementioned segmentation results to select patches belonging to the vehicle and to mask other patches, allowing MAE to learn identity-sensitive features in a self-supervised manner. Finally, we present a background-aware meta-learning method to fit varying degrees of background interference in different scenarios by combining different background region ratios. Our experiments demonstrate that the proposed method has state-of-the-art performance in reducing background interference variations.
28 March 2024 in Computers in Biology and Medicine