DEM Registration and Error Analysis using ASCII values

Digital Elevation Model (DEM), while providing a “bare earth” look, is heavily used in many applications including construction modeling, visualization, and GIS. Their registration techniques have not been explored much. Methods like Coarse-to-fine or pyramid making are common in DEM-to-image or DEM-to-map registration. Selfconsistency measure is used to detect any change in terrain elevation and hence was used for DEM-to-DEM registration. But these methods apart from being time and complexity intensive, lack in error matrix evaluation. This paper gives a method of registration of DEMs using specified height values as control points by initially converting these DEMs to ASCII files. These control points may be found by two mannerisms either by direct detection of appropriate height data in ASCII files or by edge matching along congruous quadrangle of the control point, followed by sub-graph matching. Error analysis for the same has also been done.