IAPRS, Vol. XXXIII, Amsterdam, 2000 DTM GENERATION FROM RUSSIAN TK-350 SPACE IMAGERY IN THE PC-BASED PHOTOGRAMMETRIC SYSTEM Z-SPACE

The paper describes a number of methods for fast DTM generation, processing and merging implemented in the new powerful PC-based photogrammetric system Z-Space, which is specially optimized for TK-350 imagery. The particularity of DTM processing for TK-350 imagery consists in large amount of DTM points; it is usually equal to tens millions. The developed DTM generation method uses terrain and image pyramids to produce a dense disparity map with resolution up to one pixel. The matching speed achieves 1500 image points per second on ordinary computers such as IBM PC with Pentium 200MHz. The high matching speed is reached by prediction from a DTM pyramid with the help of a geomorphologic map. The regular DTM matrix is produced in geodesic northing easting coordinates system by fast bilinear interpolation of 3D points. The speed of full DTM generation process achieves 700 DTM points per second. To produce very large DTM limited only by available hard drive space a procedure for merging of overlapped DTMs is developed. The accuracy of the DTM is measured in ground control points. The typical error variance is 10m in height.