So...
Alexey...
- For Sequential, do the filenames matter??? Or folders?
- When is using Estimated for a 2nd run of Align Photos worth doing?
- Are their any other tips for Aligning these UW photos with no GPS data?
Thanks!
I'd also love to know more about sequential preselection.
My guess would have been that choosing sequential additionally ensures that sequential pairs are always matched/compared, when they may have not been picked up by generic preselection, rather than excluding any non-sequential pairs.
That doesn't make complete sense though, because I would think that 99% of all photos taken by everyone with any hint of method to their madness would take one photo after another in an overlapping sequence, in which case it would make sense for Metashape to do this regardless. And as the number of sequential pairs only increases linearly with the number of photos, there's hardly any processing time penalty for doing it.
Also my guess doesn't make sense because if it was additional, then you should be able to choose this in addition to estimated and source reference preselection types, rather than only being able to choose one of three.
Anyway, my guesses are no use to anyone, including myself, so I'd love to know what it's doing really.
These are great points.
All my scans are sequential. And even with my non-standard rig of having two cameras on a 3m pole, the time-lapse images from both do still overlap sequentially, just in a zigzag, rather than just forward... Hence i'm seeing the alignment process zip along through the Selecting Pairs stages, etc, where it'd usually take ages.
Could Metashape ever have the ability, or an option to enable it to deal with multi-mission, multi scan projects?
Where we get the benefit of sequentially aligning the individual scans, where the photos are all overlapping sequentially, and then it does another stage without Sequential, such that it can then find matching pairs contained between different scans. It does this already obviously, with sequential turned off, and it can align multi mission, multi scan projects but it takes ages (as i know too well). Could it also perhaps be intelligent, and take the rough locations of the cameras in aligned sequentially, then find the first few pair using brute force, but then switching to the intelligent way of comparing pairs that are in the same rough area?
Metashape seems to be used a lot of applications where the data is collected in multiple missions, flights, dives. Where the scans are either carefully adjacent, or crossing, but which overlap. And each of these missions, flights, dives do have sequential cameras. So couldn't Metashape use, as James is getting at, a hybrid approach, where it will try sequentially and non sequentially to align the cameras.
UPDATE to my previous post:
The troublesome scan i was testing with Sequential, it failed to align 2/3 of the cameras, rather than a the 10% before. I'm guessing because the sequence was 'broken' by a run of a few bad quality cameras... It just stops there. Couldn't MS switch back to the normal 'brute force' way, then when it's finding images that have a matching pair, then see if it can switch back to sequential.
And thinking back to a scan from yesterday, it did have the last section of the scan shooting off on a completely wrong plane... So i selected all of those cameras and realigned them, and they then aligned great... BUT... The scan did cross over itself a few times... Did MS find matching pairs between the cameras in the path where it crosses overs??? Or are they independently lying on top of each other... EEEK! Now I'm worried... Will have to somehow check this...
Alexey,
Please, please, please can you explain, with a lot more detail, all of these alignment options, and MS's methods, with example, and advantages, disadvantages of each. We really need the details here. Alignment is the step that EVERYONE has to start with!