Workflow to process the Photography of "PHANTOM 4 RTK"

[rmowbs]

Thanks Alexey, will stick with regular "in-field calibration" as you say. I have already reused this data returning good results.

[cristian]

We buy Phantom 4 RTK to use PPK option in our works.
We have reached accuracy of 2 times the pixel size in elevation, compared to GCP.
For this we have used external calibration from a work with GCP in similar height conditions. (150 meters)  calibration in field. However, we have always agreed to put some CPG to review our quality of work.
In the case of road surveys, using "corridor", we put a GCP every 500 meters.

[xabierr]

I have been doing some testing with the new P4R and getting some good results. I can't seem to enter the DJI dewarp Xmp data so that it means anything to Metashape, has anyone else yet? The auto adjusted camera parameters seem to been getting pretty good accuracy without GCP and even better just using 1 GCP.

Was flown with D-RTK2 base over known point shot with Trimble R10, lens correction turned off in RTK app. Ground control also shot with R10.

Coordinates converted to OSGB1936 in metashape before alignment and loading GCP.

I have tried to do a lens calibration with the chessboard in metashape but get very different parameters than what I see after a flight and optimisation. Anyone else been able to calibrate the P4R lens successfully with metashape?

Without running the optimisation the Z error is over 21cm but down to 6cm after. Using just one GCP tightens things up further to less than 3cm.

See reports https://drive.google.com/drive/folders/1LekTi82gf9Vq4cYkg_4s79YTnccYmgrr?usp=sharing

Let me know your thoughts.

Cheers

Why did you use all coefficients except p3 and p4 when optimising? What is the general rule of thumb when choosing them?

[Alexey Pasumansky]

Hello xabierr,

For general cases we do not suggest to optimize (and actually use) p3 and p4 coefficients. THis recommendation is based on our experience with various project types and user's feedback.

[WSurvey]

Hello xabierr,

For general cases we do not suggest to optimize (and actually use) p3 and p4 coefficients. THis recommendation is based on our experience with various project types and user's feedback.

My experience now with a few Phantom 4 Pro/Adv cameras is that they have some quickly changing radial lens distortions that need P3 and P4 solved for in order to best model them. Also the alignment process seems more accurate when tested against PPK if the corners of the photos are masked out from keypoint detection. It is my opinion that nothing good comes from these corners of P4P JPGs.

[droneservicesireland]

So is there any more clarification on settings / workflow for P4RTK ? After reading through the whole thread, doesn't seem to be a consensus  on proper workflow.

[Bene]

I am also very interested in a complete workflow for P4RTK.

Cheers,
B

[d.hesse]

so am I :-)

[Tonci992]

Has there been a complete workflow in Agisoft for this? Like a step by step thing??

Thank you in advancee