Crowd flux analysis and abnormal event detection in unstructured and structured scenes

摘要

This paper presents a spatio-temporal grid-based framework to deal with the complexity of structured and unstructured motion flows that can effectively group optical flows in the field of view into crowds. This approach utilizes motion flows of the features based on a grid in a scene. In order to detect abnormal events in crowded scenes, the proposed method measures motion features including the speed and direction of moving objects based on a spatio-temporal grid-based approach for flow representation. Experiments have been conducted on several different videos in three domains that are crosswalks, escalators, and highways. To evaluate and compare the performance of our method to other methods, ROC curves are plotted which take into consideration both detection rate and false alarm rate for multiple threshold values.