AT failed on a model consisting of 12,245 Aerial Photos with 7 Ground Control Points. Error message states it took place during Bundle Adjustment. Please advise! Appreciate any help!
Out of curiosity .. does it AT without the ground control? My usual workflow - as I don't have RTK on the drone - is to run the AT first - then add say four control points in enough photos to get it georeferenced .. then add more/the rest.
Also did you do a calibrate run with a few photos? So settings for the big AT then would be "Keep camera calibration" .. I usually change to high tie points ..
We use manually installed GCP's since we do not have RTK on our drones either. I ran the AT with the GCP's due to the huge dataset which takes a good few hours to run AT on our computer. Currently processing the AT with the "Keep camera calibration' settings and will see how it goes.
A trial run of a part of the model without GCP's ran fine (AT+ Production). Our dataset mainly consists of grid patterns of 90 deg and 45 deg taken with a DJI GO4 app and manual orbits around some of the structures. I wonder if combining the manual orbits with the grid patterns is somehow affecting the overlap? I am just spit balling.
Single drone or multiple?
From where you are at - I'd do the following:
1) check out the post and confirm your imagery complies with everything at camera calibration
2) get a subset of your images over a "complex" area - like a building - so all four obliques .. nadir.
3) create a new block - call it "Calibration" will do
4) add photos you have selected from (2)
5) run an AT on the "Calibration" block per the calibration post (1) - so multi-pass on optical calcs - high tie points
6) once that is run - export the optical properties to a file - keep them with your job
7) clone your big existing block - set "additional" parameters to "structured aerial data set"
8) import optical properties on to the new clone
9) run an AT - "Keep camera calibration" .. and set tie points to high
10) how did it go?
If you have multiple drones - this needs to be done for each unit and the photos need to be split - each group will have slightly different focal lengths etc - even if the same model of drone.
Did you have auto-focus or manual infinity focus? Need infinity - using AF changes the focal length per photos (perhaps)
Typically when I have done something like this - I'd do each flight as a separate block - so "Nadir"; "North Oblique" etc .. with the survey control and so on ..
Then I merge the blocks and (can) merge the photos groups per drone - and run a final AT.
Having said that - sometimes I have _FELT_ (no empirical evidence) - that the separate photo blocks per "mission" (eg per oblique) has resulted in a better mesh .. rather than trying to fudge the final AT - you might like to try a few tiles per and post final merged AT and decide for yourself.
Oh and you mention GO4 .. try GS Pro?? There are a few apps out there - for complex stuff we are now flying overlapping orbits .. but we are manually calc'ing them in Autocad and programming up GS Pro. Drone Deploy or Harmony can apparently do them automatically - but manually allows us to tweak the centres subject to building layout etc.
Thanks for that James! Will run AT as per the workflow you've mentioned above. We used a single DJI Inspire 2 drone with a Zenmuse X4S camera to capture the entire dataset. Also, we did use the DJI app for mapping the grid flights (NADIR+Obliques) and then conducted manual orbits of the towers to capture the facades. What is your preferred app for more complex jobs if I may ask? The buildings we capture for city modelling purposes are usually around 100-150m and as you may know, it is next to impossible to to obtain orbits at lower levels (to avoid 'holes') without facing connectivity issues. Also, as a matter of interest, what is the typical pricing model you use for processing 3D Reality Models.. where you are at? We have recently got into the Reality Modeling market in the Middle East and are looking to develop a feasible pricing model.
There are some many apps out there .. Altizure .. DJI GS Pro .. Drone Harmony .. We tend to stick with GS Pro .. does everything we need. You can add orbits to GS Pro too for about $15 from memory .. wasn't much.
You probably should consider terrestrial photogrammetry too - so shooting the streets / facades from ground level .. could add.
Then again - check out the Aerometrex channel on YouTube - they use helicopters and phaseone's etc and fly orbits mostly from what I understand. There is a video for the Papal visit showing some of this.
As to price - it is usually part of an overall capture - so mostly laser scan - but we process the imagery anyway.
Some jobs we are doing with just photos - depends on the job. Pricing is competitive to survey day rates basically, plus some compute time.