关键词: 人群异常运动, 金字塔Lucas-Kanade光流法, 帧平均加速度

Abstract: How to effectively analyze and monitor sudden crowd abnormal condition has become a research hotspot issue at present. The most common way to detect the crowd abnormal motion is to analyze the change of the speed. However, in addition to the speed, apparently the direction of the motion is another important feature of the velocity. Studies show that when the crowd motion is abnormal, the most significant phenomenon is the speed or the direction of the crowd motion suddenly changes. For instance, from slow walking to fast running, sudden change of the motion direction. Based on this, this paper proposes a new algorithm of detecting the crowd abnormal motion that is based on acceleration. The algorithm uses the pyramid Lucas-Kanade optical flow method to analyze the crowd motion by calculating the “frame average acceleration”. The experimental results show that the proposed algorithm can rapidly and effectively detect the crowd abnormal motion. Moreover, compared with the method of only using the speed to detect, the results of the proposed algorithm are more accurate and the range of applications will be more extensive.

Key words: crowd abnormal motion, pyramid Lucas-Kanade optical flow, frame average acceleration