Agisoft Metashape

Agisoft Metashape => General => Topic started by: fabvin on October 26, 2020, 12:59:39 AM

Title: Add new images to an already aligned chunk
Post by: fabvin on October 26, 2020, 12:59:39 AM

Dear all,
I wanted to know if it is possible to add new images to an already aligned chunk, for example, when we process a chunk with a lot of images that took many times for alignment, then we took new pictures in the field to complete some parts of the chunk, and we want to keep the aligned images during the new alignment procedure.
Is there a way to do that, without considering the merging chunk options as we wanted to use the SIFT algorithm for aligning the new images on the existing chunk?
Best regards
FabVin

Title: Re: Add new images to an already aligned chunk
Post by: cbnewham on October 26, 2020, 11:40:42 AM

Just add the photos and perform "align photos", making sure the "reset current alignment" checkbox is unchecked.

Title: Re: Add new images to an already aligned chunk
Post by: Alexey Pasumansky on October 28, 2020, 02:42:11 PM

Quote from: cbnewham on October 26, 2020, 11:40:42 AM

Just add the photos and perform "align photos", making sure the "reset current alignment" checkbox is unchecked.

I just wanted to add that this approach would work, if the key points have been stored in the chunk. You can check for their presence in the Chunk Info dialog.
In order to allow key points the option "Keep key points" should be enabled in the Advanced Preferences tab prior to the initial alignment.

Title: Re: Add new images to an already aligned chunk
Post by: fabvin on November 08, 2020, 12:47:24 AM

Thank you very much, Alexey, it works perfectly!

Title: Re: Add new images to an already aligned chunk
Post by: fabvin on November 20, 2020, 11:47:40 AM

Finally, it works, but the time to align the new images to an already aligned chunk is extremely long... It takes 12 hours to add 50 supplementary images whereas the time necessary to align those 50 images by themselves didn't exceed one hour.

I consider the following parameters for alignment:

Accuracy: High
Generic, Reference and Reset current alignment: unchecked
Key point limit: 200 000
Tie point limit: 20 000
Guided image matching: unchecked
Adaptive camera model fitting: checked

Maybe the scrolling list: Source/Estimated/Sequential is the key of the problem. I select Sequential but maybe it was the wrong option?

Best regards
Fab

Title: Re: Add new images to an already aligned chunk
Post by: cbnewham on November 20, 2020, 07:44:32 PM

I've noticed increases of time when adding photos and also worse accuracy compared to just starting the whole thing from scratch.

Title: Re: Add new images to an already aligned chunk
Post by: PROBERT1968 on November 20, 2020, 09:09:53 PM

I wonder if you had disabled your markers ?  I don't know if that made a difference .