Can't calibrate images of a cornfield

Good morning,

I flew a cornfield yesterday and tried to create a map using Pix4DMatic. I selected both Flat scene low texture and map as calibration options, but neither worked. I got calibration errors.
Looking at the screenshot, I sense something else is going on. The green calibrated images do not match the blue input camera positions. I had 20+ satellites while flying.

Any ideas?

Hi, could you please share the quality report of your project? This will provide more info to reply to you more precisely.

Do the blue or green camera positions look closer to where they’re supposed to be? I assume blue, but your confirmation would help. This together with the report should help to find the issue.
Thanks

HI Pieroangelo,

The blue ones are the more accurate location. I also added the log files. I had to zip one of them and it was too big.

Thank you!

W42 West Cornfield-quality_report.pdf (343.8 KB)
2024-09-03_20-58-25.zip (1018.3 KB)
2024-09-04_11-22-50.txt (16.4 KB)

Hi @petermorssink
Thanks for sharing, in the quality report I see that the camera optimization went far away from the initial parameters:

Looking at the camera positions, I see that it is bending too:

And in the processing options, it looks like you’ve modified the calibration settings from the template:
image

I’d first set the processing options settings with the template “Nadir”. Then, I’d modify the “Internals confidence” setting to “High”, to address the camera optimization issue.

Could you try that and let me know how it went? Please share a quality report too.

This worked much better. I apologize, Pierangelo. I don’t know enough about the different parameters and what they do. I have to make the time to read the manuals. Almost every day, I find new things.

Thank you!

W42 West Cornfield-quality_report_2024-09-05_10-02-37.pdf (391.9 KB)

As a follow-up, a certain path is not correct. You can see the field projected on the asphalt. In the 3D view, you see a part floating above ground level.
Edited: I added the last screenshot, which shows that most of the field is double and floating




The new quality report shows that the camera optimization difference was fixed, however you still have the project that is bending:

It is good to know that it is a corn field, it’s rather flat and with a repetitive content.

In this case, I’d try one of two things:

  • select the “Low texture planar” in the Calibation > Pipeline settings.
  • set the Calibration > Image scale to 1/4

As usual, I’d check the quality report once you’ve tried this out. And we can go from there.

Thank you for your reply. I tried your new parameters, and the calibration is not even finished. I can’t get it to generate a QA report, so I took a screenshot of the error reported.

mhm, sorry about that. What if you try with image scale at 1/2?

Do you have Ground Control Points (GCPs) measured in the area? This would be another way to remove the bending that you’re seeing with the settings higher up in the thread.

Last resort, you could try a scale constraint, which may fix this too. You’d need to know something of a known distance and you could enter a scale constraint. I’ve seen this remove bends too.