Support for OPF (Open Photogrammetry Format) import

[abey79]

Pix4D, a major player in the drone-based photogrammetry software, recently proposed an open datafile format for photogrammetry content called OPF:

OPF at its core is a specification for a flexible and extensible format that stores all of the data related to a reconstructed 3D model made with photogrammetry. This data includes information on both inputs and outputs of the photogrammetry process:

• The input data includes information about the cameras used, their parameters, coordinate reference system, control points, the scale, and more.
• The output data includes information about the camera calibration and the dense reconstructed point cloud.

OPF primitives appears to nicely match Rerun's, so it might be interesting to somehow support importing of these files. This could be (at least initially) done as a Python example, using Pix4D's provided library.

Such photogrammetric projects can sometime extend to 10+ million 3D points and 1000+ camera poses/images.
So, in addition to the intrinsic value of supporting an open data format, one possible motivation for such an effort could be to obtain real-world, stress-testing datasets.

[abey79]

This has been postponed due to errors with the only available example project, see Pix4D/pyopf#3.

OPF being very recent and not (yet) widely used, working on this should be delayed until:

1. more demo projects are available (should be soon™️)
2. a clear need for massive benchmarking/test project emerges

[abey79]

Some more OPF examples are now available here:

https://support.pix4d.com/hc/en-us/articles/360000235126-Example-projects-real-photogrammetry-data#labelS1