Hi everyone !
(I would say "Hi Alexey" but maybe somebody else has faced to this problem)
I've handle a couple of aerial measurements using UAV (DJI Phantom 4 Pro) and coded target (circular 12 bits) as GCPs.
As I presented in other topics, I have had lots of test to determine the minimal size of target regarding the GSD, so my following problem does not concern target size.
My surveys were composed of around 1500 pictures for an area of 15ha. 18 targets were set on the floor and measured using GNSS RTK.
The problem is that the target detection struggle to get all the visible targets on pictures. I would say for a 1/3 of targets, they are detected on all pictures, for a 1/3, detected on only a couple of pictures, and for the last 1/3 of targets, nothing is detected.
I attached a set of 4 pictures that show there is no link with distance / size / angle or whatsoever. Indeed on pictures 1 and 4 the target 9 is detected, but not in the pictures 2 and 3.
I got the same result for tolerance 30 and 100...
If somebody can help... Everything was OK before.
Regards