Monocular 3D human pose estimation is an ill-posed problem in computer vision due to its depth ambiguity. Most existing works supplement the depth information by extracting temporal pose features from video frames, and they have made notable progress. However, these approaches divide a long sequence of video frames into multiple short sequences for separate processing, which leads to the loss of complementary information between sequences. Furthermore, the short-term temporal correlation among frames in a sequence is often not fully exploited. To model temporal dependencies efficiently, we propose the frame-padded multiscale transformer approach, which includes a frame-padded video sequence preprocessing step and a multiscale temporal transformer backbone. Our approach addresses the omission of the temporal features of edge frames in existing approaches by padding video frames in the shallow layer. In addition, we extract the temporal information of 3D human poses using a multiscale transformer to enhance the short-term correlation of human pose skeleton keypoints. Extensive experiments validate the effectiveness of our approach on two popular datasets: Human3.6 M and MPI-INF-3DHP. The results show that our approach achieves state-of-the-art performance. The code and model are available at https://github.com/ygx7/FMFormer .

With the aging of the human body and the reduction in its physiological capacities, falls have become a huge threat to individuals’ physical and mental health, leading to serious bodily damage to the elderly and financial pressure on their families. As a result, it is vital to design a fall detection algorithm that monitors the state of human activity. This work designs a human fall detection algorithm based on hierarchical decision making. First, this work proposes a dimensionality reduction approach based on feature importance analysis (FIA), which optimizes the feature space via feature importance. This procedure reduces the dimension of features greatly and reduces the time spent by the model in the training phase. Second, this work proposes a hierarchical decision-making algorithm with an XGBoost model. The algorithm is divided into three levels. The first level uses the threshold approach to make a preliminary assessment of the data and only transfers the fall type data to the next level. The second level is an XGBoost-based classification algorithm to analyze again the type of data which remained from the first level. The third level employs a comparison method to determine the direction of the falling. Finally, the fall detection algorithm proposed in this paper has an accuracy of 98.19%, a sensitivity of 97.50%, and a specificity of 98.63%. The classification accuracy of the fall direction reaches 93.44%, and the algorithm can efficiently determine the fall direction.