Hi ODM community!
First, let me thank you for all your work and an amazing software!
I’d greatly appreciate some thoughts on the project I’m working on. Here’s the rough outline, but happy to provide more details.
Software: ODM version 3.0.4 (same behavior on WebODM version 1.9.19) both using native installers on Windows 10.
Context: The images come from flying DJI Mavic 2 Pro over low-statured vegetation following the recommended cross-grid + small offset flight plan.The reconstruction seems to work perfectly in most of the scene and the quality of ground features is totally satisfying throughout. We use GCPs to georeference the model and that seems to be a success too.
Problem description: In a certain parts of the scene (~25% of ROI) there is =< 70 cm error (more of a shift than random error) in ground mapped RTK points and the model. In the remaining 75% of the scene the match is almost perfect, suggesting this is not a GPS error.
Things I’ve tried that did not lead to pretty much any changes in this aspect (neither positive or negative):
- increase the number of photos referenced in the gcp_list.txt
- re-run the process using only nadir shots (included in the reprex data)
- various quality settings from very high (ultra) to medium, including mesh-size, min-num-features, resolution, pc-quality, feature-quality.
- Matcher type: bruteforce, flann; sfm_alogrithm: incremental, triangular, plain
- rolling shutter options on/off
What aspects of the processing workflow are likely contributing to this artifact and what can I try to improve the errors? Happy to experiment more and try to improve outputs as matching the model to ground features is important.
If this is just the limitation that can’t be resolved, can this behavior be retrieved/approximated/predicted from any of the ODM outputs (reports, etc)?
Dataset: repex_odm1 - Google Drive
Illustrations of the problem:
Entire scene (white=gcp, purple= rtk pts) with the affected areas roughly outlines:
GCP (representative of all GCPs)
Good matches (~75% of ROI):
Poor matches (~25% of ROI):
Transition from good to bad matches:
Would greatly appreciate any feedback!!