Falls are a major health threat for older people. A timely assistance can reduce the extent of physical injury caused by the falls. Currently, low-cost and convenient video surveillance systems based on ordinary RGB cameras are widely used for improving the safety of people. The fall detection is a research hotspot in intelligent video surveillance. In this work, we propose an unsupervised fall detection method. The proposed method first converts the RGB video frames into human pose images to eliminate the background interferences and focus on human motion and protect privacy. Afterwards, the future pose images are predicted by using the continuous historical human pose images based on a constrained generative adversarial network (GAN). Finally, the prediction errors of the human pose images and the anomaly scores of actual poses calculated by using the traditional hand-crafted features are used to realize the fall detection. As compared to the existing vision-based fall detection methods, the proposed method possesses strong generalization ability, and is robust to environmental interferences and small local occlusions, and effectively protects the privacy, and avoids time-consuming data annotations. In addition, in this work, a new large-scale and comprehensive fall dataset is created and is available for download. We perform extensive experiments on the public benchmark datasets and the proposed dataset. The results demonstrate the validity and superiority of the proposed method.

Semantic segmentation of remote sensing images is essential for various applications, including vegetation monitoring, disaster management, and urban planning. Previous studies have demonstrated that the self-attention mechanism (SA) is an effective approach for designing segmentation networks that can capture long-range pixel dependencies. SA enables the network to model the global dependencies between the input features, resulting in improved segmentation outcomes. However, the high density of attentional feature maps used in this mechanism causes exponential increases in computational complexity. Additionally, it introduces redundant information that negatively impacts the feature representation. Inspired by traditional threshold segmentation algorithms, we propose a novel threshold attention mechanism (TAM). This mechanism significantly reduces computational effort while also better modeling the correlation between different regions of the feature map. Based on TAM, we present a threshold attention network (TANet) for semantic segmentation. TANet consists of an attentional feature enhancement module (AFEM) for global feature enhancement of shallow features and a threshold attention pyramid pooling module (TAPP) for acquiring feature information at different scales for deep features. We have conducted extensive experiments on the ISPRS Vaihingen and Potsdam datasets. The results demonstrate the validity and superiority of our proposed TANet compared to the most state-of-the-art models.

Rain streaks can seriously degrade the visual quality of an image and are detrimental to subsequent algorithms such as object detection and semantic segmentation. Therefore, removing rain streaks is a very important task. The deraining task has two main limitations: the first is to encode information about rain streaks in different densities and directions, the second is to keep the background details of the image while removing the rain streak. To address these limitations, we propose an effective algorithm, called multi-stage and multi-scale joint channel coordinate attention fusion network (MMAFN). We mainly propose a two-stage network structure, both of which use an encoder-decoder network to extract features. The first-stage network extracts coarse features and the second-stage network integrates the features of the former to further refine features. We design the joint channel coordinate attention block to encode features of rain streaks in different directions and densities. In addition, to better fuse features of different scales and enhance the generalization performance of the network, the inception attention branch block and the multi-level feature fusion block are designed. Extensive experiments substantiate the superiority of the proposed network and prove that our method outperforms the recent state-of-the-art method. The average PSNR of the five test sets is improved by 0.2dB. On the Test100 test set, the PSNR is increased by 0.93dB at most.