Bidirectional Pedestrian Traffic Measuring System Using Radiance Detection

Abstract

For security and safety reasons, it is important to konw the number of people entering and exiting a building, as well as the distribution of people on particular floors.
Basically, the number and the direction of pedestrians can be measured by monitoring a pair of parallel lines across the pedestrian way. The authors have developed a bidirectional pedestrian tr a ffic measuring system using a pair of linear CCDs for accurate, real-time measurement at a heavy pedestrian traffic site. The system monitors the radiance at two parallel lines on the floor from above, and measures the number and the direction of pedestrians crossing the lines by computing the change in radiance patterns.
The system consists of an image pickup unit (including optical system, CCDs and the driver), a data transfer unit, and an information processing unit (personal computer). The data transfer unit has two ports of buffer memories and transfers data from the image pickup unit to the information processing unit at high speed (approximately one frame of data per millisecond) in the asynchronous transmission mode. The information processing unit computes the number and the direction of the pedestrians from the two-valued radiance pattern data obtained by the CCDs. The pedestrian measurement algorithm has been designed so as to cope with the cases where more than one pedestrian crosses at the same time either side by side or one after another without a space between them.
The experimental system with an optical system of F2.0, a CCD storage time of 20.0 ms, and an illuminance of 32.2 lx on the CCD photoreceptor surface, has made accurate measurements of pedestrians even when they crossed in opposite directions or side by side at the same time.