Rotation of object to plane of best fit

[eastonmbio]

Our group is monitoring sections of coral reef using photogrammetry scans, part of which requires orthomosaics to track 2D coral growth over time. We are trying to figure out how best to ensure that the top XY view of the reef is as consistent as possible between time series. I'd like to know first of all how the automatic calculation of what the top-down view of the object is? Our data acquisition is primarily nadiral which I think is important but there are some oblique camera angles too, which I am assuming changes the automatic projection. My assumption is that the top of the object is calculated using the average viewing angle of all the cameras in a scene.

Ideally, the top-down view should be perpendicular to the plane of best fit of the growth of the reef slope - is there any way to rotate the object to this view using python? Our coded markers are not permanent features and are not always parralel to the slope, which I think would prevent us from using a marker-based projection in the orthomosaic.

[Alexey Pasumansky]

Hello eastonmbio,

If you are not applying any reference to the chunk, then the default orientation of the coordinate system after alignment will be almost arbitrary - corresponding to the first camera used for the alignment (which cannot be predicted).

Would it be sufficient for your needs to modify the coordinate system of the chunk so that the XY plane would correspond to the best fit plane for the tie points inside the bounding box?

[random_access]

Hi Alexey,
I'm interested in a solution to this as well.
Will you be able to drop some hints on how to implement this?