I’m having an hard time to properly process 3 differents flights in one project. The object of the survey is a large and mostly flat agriculture land with some sectors covered in vegetation. We perform 3 differents flights for about 900 photos, 70 mt altitude with an high overlap, so I tried the following:
Process the whole data as one project and “standard” settings, resulting in an inclined surface, several sectors empty and several errors reported in the process
Process 3 sectors separately, trying either the standard settings, either the following the “alternative” calibration method with 1/2 keypoint image scale
Merge the 3 sectors eventually
I’ve already tried to follow the advices found in these articles
Also, here’s some screenshots of the results… even if the altitude was always the same, it looks like the 3 flights has been placed at differents altitudes…
I don’t honestly believe it’s a computer issue, I’ve already tried to have it processed on a different desktop. Also, it’s a several GB data-set. I can share a part of it, maybe you could have a look if there’s a problem with the pictures…
I’ve also proceed to re-optimized the camera followingthesearticles, the final report has no issue alert
but the results remained unsatisfying
It really looks like there’s a specific problem with the drone altitude detected by the software
It’s not computer related issue. There is just so many things you need to change to process that project successfully.
There’s still 7 different blocks which means that there is some kind of misalignment. One is obviously here:
If you don’t want to share the whole dataset then you should manually change the altitude in exif-data to match correct altitude. Next you should use manual tie points in common area between flights.
I looked at the pictures in the link you provided and in my opinion overlap wasn’t sufficient. Flight number 3 seems to be out of focus/blurry.
I would go out in the field and fly the same area again if possible. This time a little higher altitude and with better overlap.
Hi Jaakko, we arrived at the same conclusion, today I manually changed the EXIF altitude (apparently it’s a common issue with DJI drones) and fix the assemble issue
Now, regarding the several uncalibrated pictures, I understand that the area covered in vegetation (on the right in the image above) might be tough to process.
I doesn’t look like the flight 3 is out of focus, not more than the others however
Also, the overlap was pretty high (80-85%) and the altitude 75 mt. Sadly the ground it’s now covered in snow, so we would have to wait to perform the survey again.
I think it might help to process the project separately (3 parts) using alternative calibration method and 1/2 image scale size. Then, I’ll have to manually calibrate the remaining pictures. What do you think?
I doubt that you can manually calibrate that amount of pictures. My advice is to wait snow to melt and fly again and you can always try different settings while you wait
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