Image Processing for Capturing Motions of Crowd and Its Application to Pedestrian‐Induced Lateral Vibration of a Footbridge

Abstract

An image processing technique to capture motions of crowds is proposed and it is applied to understanding pedestrian‐induced lateral vibration in a footbridge. Firstly, an outline of recording sequential images of vibration in the bridge is described and, then an image processing for human‐head recognition from a single image of crowd is developed. In this method, conventional template matching techniques with human‐head templates are extended by employing some selected templates, an updated search‐algorithm and a classifier for clustering. Consequently, more than 50% of human‐heads could be identified by the proposed method. Then, motions of detected human‐heads, together with the bridge response, are tracked. Finally, interaction between the motions of pedestrians and the vibration of the bridge is discussed, with the emphasis on synchronization between the responses of the pedestrians and the bridge.