I am doing geomorphological mapping with historical aerial images (framed photos from photogrammetry survey), which typically overlaps 60%-65% along flight line, and 20%-30% across lines. Surprisingly, I am getting good results using ODM with these images.
I am aware that ODM was designed to work with images overlapping 70% or greater, so in general, the point-cloud is produced only in areas covered by three or more images taken from different angles. In any case, I think that it should be possible to have the point-cloud generated in areas with only 2 images.
Is there a way to tweak OpenSfM parameters in order to have point-cloud generated in areas covered only by 2 images? I saw that PMVS has a flag for minimum number of images (–pmvs-min-images), but I couldn’t find a similar one in OpenSfM.
A reproducible example can be executed with these raw images (a shapefile with footprints is included). I used the following parameters:
./run.sh projectname --project-path path/to/project --resize-to 5976 --force-focal 152.929 --orthophoto-resolution 1 --min-num-features 30000 --matcher-neighbor 14 --mesh-octree-depth 12
I also used images without the black border as inputs, but again, point-cloud was produced only in areas covered by three or more images, showing a strip pattern.
Update 2018/04/18, 18.54 AST
Found a mistake in “gcp_list.txt” contained within the ZIP file, but it is already updated.