Hello all,

I have been having a lot of trouble with the photos that I am capturing with my P4 RTK.  While I have been able to improve the photo results, I am still seeing a fish eye effect (or bowing on the outer edges of each photo).  See one of the photos below.

I am using the P4RTK and GS RTK app with the following settings:  
"Timed shooting"
Aspect Ratio is 4:3
White Balance is set to "Sunny"
Metering Mode is Average
Shutter Priority and Distorsion Correction are not checked

The flight speed was about 5.7 m/sec.

Please advise any thoughts as to what may be causing this.  The resulting photos are causing a lot of noise in the Pix4D processing results.

Thank you for any advanced help

Pix4d process the images with the fish eye effect, in fact is better to add this raw images without  distortion correction

Can you post the output from the Phantom before corrections?

How did the original look?

Can you post the original

Here is the original (full sized photo):





This is an image from the same field flown with a Phantom 4 Pro at similar height and speed.





This image is from an earlier flight with the P4RTK. Note the dark corners and the bulging is worse.

I work every day with phantom 4 rtk and i can assure you, that every picture i will take in default mode (without checking "Distortion Correction") has that fish eye effect.

In fact, if you will process the images with a photogrammetric software (like Agisoft Metashape or Pix4D) it is suggested that you leave it default (without checking "Distortion Correction"). The software will correct the distortion better than the drone.... You can read this in the P4RTK manual

If you want that planar look you have to process the images in PIX4D and generate the "Orthophoto"

Thank you Guille.  I flew the entire site with a P4Pro and have processed it with good results.  I did fly a couple areas with the P4RTK as a test, but I haven't been able to run those areas through Pix yet.  I will give that a try and let you know the results.

The image shown above is the best one that I have been able to get from the P4RTK as most of them look like the last photo that I posted with the dark corners.  With those issues, I still get pretty decent results on the ortho photo, but the cloud is very noisy and takes a ton of time to clean up.  It is a lot of wasted time that I fear is caused by poor setting selection. I believe that I am getting close to getting it right though.

Thank you again for your help.

Well i have to say that making an orthophoto from an area with a lot moving object (like athletes in the arena) is not the best BUT you can do it anyway.

Maybe the  noise is due to this moving object, maybe are the parameters in pix4d or sometimes the software doesn't read the Exif (the exact location of the pictures).

There a lot of things which can explain the noisy, but No, the fish eye effect in the pictures is not one

n75baker Posted at 2020-9-29 06:03
Thank you Guille.  I flew the entire site with a P4Pro and have processed it with good results.  I did fly a couple areas with the P4RTK as a test, but I haven't been able to run those areas through Pix yet.  I will give that a try and let you know the results.

The image shown above is the best one that I have been able to get from the P4RTK as most of them look like the last photo that I posted with the dark corners.  With those issues, I still get pretty decent results on the ortho photo, but the cloud is very noisy and takes a ton of time to clean up.  It is a lot of wasted time that I fear is caused by poor setting selection. I believe that I am getting close to getting it right though.

Hi, I hope you are keeping safe.
I have the same issues you described with the black corners and fished eye effect.

Did you find out what settings to change to fix this?

Thanks.
Juan

Hello Juan,

All is well here! I hope that you and yours are safe as well.

The setting that I think caused my problems was the aspect ratio.  On my P4 RTK with the GS RTK app, the default setting is 3:2.  Manually changing this to 4:3 has cured the problems that I was having.  There is still some curvature in the image, but the dark corners are gone.  We have completed multiple flights since having the problem, and all have generated good clean point clouds with tight accuracy.

I hope that this helps.

Regards,
Nat