Where can I find background information on the concepts of ODM?


#1

Dear ODM-Team,

I am trying to understand the whole workflow of ODM, eg.:

  1. What are the basic steps from “taking drone fotos” via “generating a point cloud” to the final orthofoto. Which step follows which step exactly? Maybe there is a flowchart somewhere that gives a nice overview?
  2. Where are the single steps explained in more detail? Maybe there is some book/Literature that gives a good overview?

I was trying to get information on this in the docs (http://docs.opendronemap.org/) and on github but without much success. I want to understand the concepts to be able to use ODM efficiently and maybe to participate in its development. I am especially interested in the generation of multiband-Orthofotos from Sequoia-Imagery (It looks like that’s still a problem: https://github.com/OpenDroneMap/OpenDroneMap/issues/190).

I would be very happy to get some information on these points!

  • Best regards, Sebastian

#2

Hey @Sebastian_Egli :hand:

I found this (a bit dated) document which has a very, very brief overview: https://github.com/OpenDroneMap/OpenDroneMap/wiki/Process-Breakdown

In short, the steps are:

  • Images metadata extraction (GPS location, coordinate system)
  • Structure from motion (from images to camera positions/orientations and sparse point cloud). We use OpenSfM for this.
  • Multi view stereo (from camera + images to dense point clouds)
  • Meshing (from points clouds to triangle meshes, we use mostly a Poisson Reconstruction approach but have support for 2.5D meshing as well)
  • Texturing (from camera + images + meshes to textured meshes)
  • Georeferencing (from local coordinates + GPS and/or ground control points to real world coordinates)
  • DSM/DTM (from real world points to elevation models)
  • Orthophoto generation (from textured meshes in real world coordinates to GeoTIFF)

If you are looking to contribute to the project, I’d recommend to focus on one single step at a time. It can be overwhelming to become proficient with all the steps all at once.

The multiband support for sequoia looks very interesting! I think this would be one of the first steps of the pipeline (right after Images metadata extraction ). We welcome contributions, so if you have other questions, feel free to ask!


#3

Hey Piero,

thank’s a lot for the overview. I’ll take a look at the different concepts.

  • Best regards, Sebastian