dji phantom 4 lens distortion correction+customized shooting time interval

[olivine]

Hi guys,
I bought a dji phantom 4 in order to generate high resolution DEM.

I took some images yesterday, and can not align them well. Only 7 of 30 images are aligned. All of them were labeled NC, which means not calibrated (from the manual).

I tried to get an Adobe Lightroom, but there is no lens distortion correction for phantom 4.

My questions are:
1)Is it necessary to make lens distortion correction before importing the images to photoscan?

2)How much will the final result be affected without these correction? If the errors of DEM due to this issue are within several centimeters, I don't think it is a big issue.

An separate question is (Maybe I should ask in Dji's forum, but I would like to try here as well):
The minimum time interval for jpg is 5 seconds, while 10 seconds for raw file. However, we need 80% forward overlap, this time interval is not small enough. Is there a way to solve this problem?

Thanks in advance! 

[drykovanov]

Hi olivine!

We've processed 4K video from DJI without any additional distortion correction and got results like this:
https://www.geoscan.aero/en/node/192
https://sputnik.geoscan.aero/object/224?accessCode=2p3lv6box2nqmnfgu25wd41ek4guzgp6auuvawadadeeaeupe2
https://sputnik.geoscan.aero/object/120

To process video we used ffmpeg to extract 1 frame pre second like this:

Code: [Select]

ffmpeg -ss 00:00:00  -i Harlech_Castle_4K.mp4 -r 1/1 images/img%03d.jpg

[olivine]

Thanks drykovanov!