Exploiting simple hierarchies for unsupervised human behavior analysis

We propose a data-driven, hierarchical approach for the analysis of human actions in visual scenes. In particular, we focus on the task of in-house assisted living. In such scenarios the environment and the setting may vary considerably which limits the performance of methods with pre-trained models. Therefore our model of normality is established in a completely unsupervised manner and is updated automatically for scene-specific adaptation. The hierarchical representation on both an appearance and an action level paves the way for semantic interpretation. Furthermore we show that the model is suitable for coupled tracking and abnormality detection on different hierarchical stages. As the experiments show, our approach, simple yet effective, yields stable results, e.g. the detection of a fall, without any human interaction.