Geospatial Object Trajectories Using a Digital Elevation Map (DEM)

 
DEM provides elevation of each pixel in the a coordinate system. When a camera is calibrated (both externally and internally), a viewing ray corresponding to an image pixel can be computed and the ray tracing method can be used to compute the intersection of the ray with the DEM. Usually the ray intersect with the ground and the target position can be pinpointed.

However, the viewing ray can intersect with the DEM at multiple points. For example, it can intersect the DEM with a tree, then at the ground. To maintain a target trajectory, some filtering mechanism must be applied to deal with the sudden jumps from ground to trees. My part in this work is to build such a smooth path. From the following image it can be seen the target trajectory remained smoothly on the road.

These experiments were done at the Bushy Run site outside of Pittsburgh, PA.

For details see our IUW 98 publication