MULTI-TEMPORAL DEM MATCHING METHOD WITHOUT CONTROL POINTS IN DEBRIS-FLOW AREA

摘要

Detecting the volume change of loose deposit of rock debris accumulated and debris discharged is one of the methods to study debris flow. The volume can be resulted by overlapping multi-temporal DEM. As traditional method is based on control points, enough matching accuracy will be achieved only if the sufficient corresponding points are available to act as control points. DEM matching without control points provides new alternate approach to complete multi-temporal DEM matching when traditional method fails. Least z-difference (LZD), one of the precise algorithm, deal with two surface only contains random errors. However, multi-temporal DEM of debris flow contains not only the random error, but also non-random error caused by the debris discharged. The effect of E on observation equation is eliminated by giving different Belief Factor (BF) to height difference according to gradient. A test is performed on multi-temporal DEM of debris flow valley located in southwest of China. The experimental results show the RMSE of the method decrease from 4.27m to 1.03 m using BF.