Whilst looking for the best available open source solution to generate terrain heightmaps from satellite stereo pairs, I stumbled upon the results of an international IARPA ‘Multiple view Stereo 3D Mapping challenge‘. The entries that secured 2nd and 3rd place used variation’s of Ames Stereo Pipeine (ASP) NASA’s automated, open-source pipeline for mass production of digital elevation models (DEMs) from very high-resolution commercial stereo satellite imagery. I couldn’t wait to dig deeper and review it’s capabilities. I started by setting up a QGIS project file which allowed me to load up my results from numerous test runs covering every key permutation available for the 2 most successful algorithms, this enabled quick comparison of sometimes subtle differences in results:
SGM (Semi-Global Matching) – a proven stereo algorithm with widesread popularity.
MGM (More Global Matching) – is a variation of SGM that can produce superior output at the cost of longer run-time and higher memory usage.
I added a red background on every resulting raster to highlight area’s where the algorithm had not been able to process. Click below image to see animated testing:
