Image analysis techniques are applied to measure number of pedestrians and their walking directions. A new algorithm, which consists of eight steps, is developed. An image device system is used to record pedestrian images in a hallway passage. An image subtraction procedure, thinning procedure, filling procedure, and boolean-type operation are derived for the algorithm to process and analyse the images. Results show that image analysis has significant potential in the area of automatic measurement of pedestrian flow data. However, in this preliminary stage, the process has only limited success. For low- to average-density pedestrian traffic situations, the accuracy in measuring the number of pedestrians and their direction of travel is about 93% and 92%, respectively. The time complexity of the algorithm and the possibility of realtime analysis are also discussed. This paper appears in Transportation Research Record No. 1281, Human Factors and Safety Research Related to Highway Design and Operation 1990.
Samenvatting