Methods for measuring pedestrian density, flow, speed and direction with minimal scatter

The progress of image processing during recent years allows the measurement of pedestrian characteristics on a “microscopic” scale with low costs. However, density and flow are concepts of fluid mechanics defined for the limit of infinitely many particles. Standard methods of measuring these quantities locally (e.g. counting heads within a rectangle) suffer from large data scatter. The remedy of averaging over large spaces or long times reduces the possible resolution and inhibits the gain obtained by the new technologies.