A novel system for tracking pedestrians using multiple single-row laser-range scanners

We propose a novel system for tracking pedestrians in a wide and open area, such as a shopping mall and exhibition hall, using a number of single-row laser-range scanners (LD-A), which have a profiling rate of 10 Hz and a scanning angle of 270°. LD-As are set directly on the floor doing horizontal scanning at an elevation of about 20 cm above the ground, so that horizontal cross sections of the surroundings, containing moving feet of pedestrians as well as still objects, are obtained in a rectangular coordinate system of real dimension. The data of moving feet are extracted through background subtraction by the client computers that control each LD-A, and sent to a server computer, where they are spatially and temporally integrated into a global coordinate system. A simplified pedestrian's walking model based on the typical appearance of moving feet is defined and a tracking method utilizing Kalman filter is developed to track pedestrian's trajectories. The system is evaluated through both real experiment and computer simulation. A real experiment is conducted in an exhibition hall, where three LD-As are used covering an area of about 60×60 m². Changes in visitors' flow during the whole exhibition day are analyzed, where in the peak hour, about 100 trajectories are extracted simultaneously. On the other hand, a computer simulation is conducted to quantitatively examine system performance with respect to different crowd density.