I am a PhD student at the University of Bern in Switzerland and currently evaluating the potential of low-cost UAVs and open-source photogrammetry software for high-resolution glacier monitoring in alpine environments. In our recent project, we draw on the open-source hardware and software project Papaparazzi UAV for mission planning/monitoring and on WebODM/ODM for the processing of acquired aerial images. First of all I would like to thank you - the ODM developers and community - for all your efforts during the last years regarding the development of a robust and powerful open-source photogrammetry software like ODM!
I started to process aerial images from our five glacier surveys during 2017 and 2018 in ODM (v. 0.3), but switched to WebODM (API version 1.1.1) recently. When comparing the ODM and WebODM orthophotos and DEMs, I noticed two things:
- The quality of the DEM (in terms of artifacts) improved impressively from the older ODM version 0.3 to the newer WebODM version (see uploaded data). Great work!
- However, the WebODM orthophoto seems more blurry in contrast to the ODM (v. 0.3) orthophoto (see uploaded data) despite the same spatial resolution (10 cm), same input data and similar processing settings. In addition, the WebODM and ODM orthophotos (based on the same input data and similar processing settings) do not match. The WebODM is shifted by ca. 15 m. Oddly enough, both DEMs (WebODM vs. ODM) match perfectly.
So far I couldn’t identify/reproduce the error. Do you have any ideas, recommendations or information of similar cases reported before? Thanks in advance for your support!
All data (aerial images, gcp list, ODM and WebODM output, log file, QGIS project etc.) are uploaded here: https://filesender.switch.ch/filesender/?vid=4e7e2c48-594f-d769-3b9c-00003c9a4c0c (1.39 GB)
WebODM (API version 1.1.1) options: dem-resolution: 50, dem-terrain-type: ComplexNonForest, orthophoto-resolution: 10, dsm: true, max-concurrency: 3
How did you install WebODM? (Docker, natively, …)?
Natively on a Unix server
What’s your browser and operating system? (Copy/paste the output of https://www.whatismybrowser.com/)
Firefox 57 on Ubuntu Linux
What is the problem?
See explanation above. Lateral shift in the order of ca. 15 m between the orthophoto and DEM generated with WebODM. However, the output orthophoto and DEM match perfectly if the same input data are processed with ODM (v. 0.3) using similar settings.
What should be the expected behavior?
- The orthophoto and DEM generated with WebODM should match.
- The texture of the WebODM orthophoto should be less “blurry” and comparable with the texture of the ODM (v. 0.3) orthophoto since same aerial images and similar processing settings were used.