Multi-level Recognition on Falls from Activities of Daily Living.

The falling accident is one of the largest threats to human health, which leads to broken bones, head injury, or even death. Therefore, automatic human fall recognition is vital for the Activities of Daily Living (ADL). In this paper, we try to define multi-level computer vision tasks for the visually observed fall recognition problem and study the methods and pipeline. We make frame-level labels for the fall action on several ADL datasets to test the methods and support the analysis. While current deep-learning fall recognition methods usually work on the sequence-level input, we propose a novel Dynamic Pose Motion (DPM) representation to go a step further, which can be captured by a flexible motion extraction module. Besides, a sequence-level fall recognition pipeline is proposed, which has an explicit two-branch structure for the appearance and motion feature, and has canonical LSTM to make temporal modeling and fall prediction. Finally, while current research only makes a binary classification on the fall and ADL, we further study how to detect the start time and the end time of a fall action in a video-level task. We conduct analysis experiments and ablation studies on both the simulated and real-life fall datasets. The relabelled datasets and extensive experiments form a new baseline on the recognition of falls and ADL.