China DSM Generation and Accuracy Acessment Using ZY3 Images

We generated DSM of all China using over 37 thousand stereo and tri-stereo ZY3 images. The original RPCs were modified though bundle adjustment oriented by SRTM. DSMs were generated through dense tri-stereo matching based on a tri-epipolar method. Modified Belief Propagation was used as global method which was more robust than standard SGM. All original DSMs were multi degree overlapping. For every 0.0001 degree horizontal grid geographic coordinate, a middle height was calculated from all DSMs containing this coordinate. All other heights whose distance from this middle height bigger than a threshold were discarded and the rest heights were averaged as result. Over 330 thousand check points were used to estimate the height accuracy of all DSMs. The RMSE is about 4 meters.