Align photos with GCPs

[emm]

Hello, I am creating an orthomosaic with multispectral imagery taken with a Parrot Sequoia camera.

On the "Align Photos" dialogue box there is an option that doesn't exist in earlier versions. I can choose both "generic" and "reference" preselections. Does anyone have advice on these options?

On the tutorial I watched, the guy had only one box with options; I have two. The default was having both "generic" and "reference" options turned on, but the tutorial advised to select "generic", and not use "reference" preselection.

Please correct me if I'm wrong. I understand "reference" preselection will re-read data from the UAV images, and "generic" focuses on the imported csv file with GCP coordinates. Is "generic" preselection all I need?

I am referencing information from the tutorial video "Photogrammetric processing of drone imagery using Agisoft Photoscan". At 26:00 he gets into the align photos step.


Any advice is appreciated, thanks
J

[n@sk]

Hello

from the manual p.16
http://www.agisoft.com/pdf/photoscan-pro_1_3_en.pdf

"In the Generic preselection mode the overlapping pairs of photos are selected by matching photos using lower accuracy setting first.
In the Reference preselection mode the overlapping pairs of photos are selected based on the measured camera locations (if present). "

It answers the question "where am I supposed to look for matches?do I match every single image with all the rest?do I use reference coords to figure out which images might overlap?"

The guy in the video is using an older version where he could only choose one or the other.
I don't think that the "re-read data from the UAV images" is entirely  accurate.
If you import approximate reference coords and leave them Checked, they will be taken into account during the alignment process.
If  you Uncheck them and use the reference preselection, the images will be matched faster and will not affect the alignment.
Judging from his latest comment on the Youtube video to another guy that points that out, I suppose that he misunderstood that part.

I hope this helps and please correct me if I am wrong.