Measurement of debris-flow surface characteristics through close-range photogrammetry

The system of Image analysis for debris flow is based on the principle of close-range photogrammetry to measure the surface characteristics of debris flow by metric or nonmetric cameras using prototype observation and laboratory experiments. The system can specify the 3D coordinates of each specified point on the surface of a debris flow. Collecting data of 3D coordinates of all the surface points, we can construct a 3D model named as the Digital Elevation Model (DEM). As a dynamic system, the DEM can work well when measurements are taken in definite interval, say 1 to 2 seconds. Some key characteristics of a debris flow, such as the surge height and pattern, geometry of longitudinal and transversal sections, surface slope, point velocity, velocity field, among others, can be promptly shown by DEM. A software, which programs the operation of the DEM, has been developed as a powerful tool in debris flow research.