image distortion correction. dji p4 rtk SDK

I got a replacement drone during the time my drone is on maintenence and the result from the first process of a dataset from this drone look like a banana. I suspect the dataset is captured in “distortion correction” mode. this replacement drone is the SDK version and i used the DJI GS PRO for data capture which im not familiar with. this probably ruined a day worth of data capture!?

Any suggestions on how to fix this?

Hello,

We would need more details to provide assistance in the most efficient way. Could you please send us the following?

▸ The quality report (.pdf format): …\project_name\1_initial\report\project_name_report.pdf
▸ Some screenshots highlighting the issue

Thank you,
Christina

I tried some different settings and so far the best result was to load the camera parameters from EXIF and then use the standard 3d map template for processing.

Screenshot from first process with failed results

Screenshot from processed dataset with cameraparameters from EXIF

Hi there! Sorry to bump an older post, I just wanted to see if anyone has experienced this issue with P4RTKs “distortion correction” and been able to turn it off.

We just started using a P4RTK SDK with PIX4Dcloud and we are experiencing the same issue you described in this post. It seems this bothersome “distortion-correction” setting is enabled BY DEFAULT on the P4RTK, and we cannot find any way to turn it off in GS Pro (or any other iOS or Android app we have tried for that matter). I feel like I am losing my mind because the UAS retailer we bought the P4RTK SDK from is saying the setting should be accessible in GS Pro, I replied asking for a screenshot showing where the setting is and they got real quiet. They have been no help at all. I’m very puzzled by this issue because I have found multiple posts from PIX4D reps on this forum stating that “distortion-corrected” imagery is not supported, AND the official P4RTK manual states something about turning off distortion correction if you plan on post-processing, AND YET for some reason with the SDK model I cannot for the life of me figure out how to turn off this d@mn setting.

/rant

I was able to download a 15-day free trial of PIX4Dmapper and replicate the issue (extreme bowling / noisy sparse point cloud) we are having in PIX4Dcloud, which looks very similar to the 1st screenshot posted above. I was able to get a better result by not using the auto-detected camera model when importing, and instead importing the internal camera parameters from EXIF. While this is great, I am still slightly concerned about inaccuracy that may be introduced by allowing DJI to dewarp the images rather than allowing PIX4D to do it (which I have been led to believe is a more accurate way of doing it).

Unfortunately this solution in Mapper does not help me because we are using PIX4Dcloud and there is no such option to import internal camera parameters from EXIF in PIX4Dcloud. So it seems I have two options:

  1. Purchase PIX4Dmapper, use that to process all my imagery from now on, and hope the distortion correction applied by the P4RTK does not introduced significant inaccuracy into the images…

  2. Continue trying to figure out how to turn off this d@mn distortion correction setting on the SDK model.

This post is a bit more rambly than I intended, but I’m curious if you have had any luck turning off the distortion correction, @Goran_Norling? Or has anyone else been able to? I’m at my wits end…

EDIT 1:

Sooo 15 minutes after I made this post, my pilot called and said he figured it out. Apparently there is some sort of option in Dronelink to enable/disable “video dewarping” or something like that. I wish I could describe it better but that’s all he told me lol.

He did a test flight with that setting switched off and voila! The images he sent me from that flight had the unaltered fisheye lens distortion and when I checked the EXIF tags, DewarpFlag was set to 0. Even though he only captured 20 images of the office parking lot I processed the dataset in PIX4Dmapper and PIX4Dcloud using the default settings and the results point clouds & orthos looked great!

This doesn’t exactly help folks who use other flight apps, but I feel so relieved. This issue has given me so much grief over the past two weeks.

Hi,

Thanks for sharing the updates and glad it can be fixed. We will have this in mind for the future.