Stitching images fails with images from Pix4DCapture

Agriculture
1

I have run several flights using Pix4DCapture and my Parrot Bebop 2. No issues with mission running, and afterwards I downloaded both the images and .p4d file on my laptop. However when I try to process them in Pix4Dfields (whether I try fast or accurate), it fails at about 16% of the way through processing with the error, “failed to stitch images.” This occurs for every flight I’ve tested with. What is the issue? I’m in the trial period but obviously not going to purchase if this isn’t resolved.

2

I don’t know anything about your machine and I haven’t used Fields so I’m going to go with the basics.
What overlap are you running? You probably need at least 70%.

3

I was running 70-80% overlap. I also previously created a camera parameter file for this drone using Pix4Dmapper and had imported these parameters to Pix4Dfields.

4

Hi Erin,

I believe if you are using a Bebop 2 there is a very strong rolling shutter correction that needs to be made. Pix4Dfields does not support rolling shutter correction like Pix4Dmapper. Did you try to process in Pix4Dmapper? How did it turn out?

5

I’ve seen mixed results using the Bebop2 in Pix4dmapper. I flew a double grid and got good results with the reconstruction, but when I did a single grid, not so great, but recognizable. Not anywhere near professional quality though.

6

Hi Erin,

Thank you for sharing with us here at Pix4D Community.
In order to better diagnose this, could you please share with us more about the following information?

  • Log files, How to export log files.
  • Side and frontal overlap that you used when acquiring the images, minimum recommended 80% side, and 75% front:
  • Flight height:
  • Weather conditions: cloudy, sunny, etc
  • Drone and camera:
  • Hardware used:
  • Dataset including the reflectance target images (if applicable).
    I will provide you with a link in a private message to share your dataset if you don’t mind.
    I would kindly suggest zipping the folder before uploading

Looking forward to hear from you!

Best,
Rosana

7

Thank you for your help. That worked for me!

8

Hi Rosana,

Thanks for your reply! I uploaded the data to the link you emailed me. For your other questions:

Overlap was 70-80% (I believe, front was 80%, side was 70%, using the default Pix4Dcapture settings)
100ft AGL
Sunny clear weather
Bebop 2 Power
No additional hardware

And I can’t export the log file, it says exports are not available for trial licenses.

9

Hi Erin,

Thank you for your reply to the post it was very helpful. I also got your data successfully.
We encounter the same problem when trying to reproduce your project. I passed this to our developing team as well.

Meanwhile, after taking a look at the images you sent and exporting the logfile while reproducing this issue by our team, I could tell the images were taken at an oblique angle instead of straight down with a fisheye len. The logfile also showed the images have large angles more than 35 degrees.

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I found that in the FAQ - PIX4Dfields, there is a question "Can PIX4Dfields process oblique imagery?" The answer is PIX4Dfields supports processing nadir images captured with a drone camera pointing straight down. If you want to process oblique images, we recommend that you use PIX4Dmapper.

I understand you ran with mapper already and the result with the single grid wasn’t great. So I came across Inputs and outputs - PIX4Dfields article later that

  • PIX4Dfields supports processing of nadir images where the drone’s camera is pointing straight down.

As well as Pix4Dfields supports only nadir images (<35-degree orientation to the ground).
Problem with the orthomosaic#7

I wonder if there’s a way to remove the fisheye in the images or reduce the nadir angles here.

Best regards,
Rosana

10

Thanks for the info! Yes I was having issues with Pix4D capture for camera angle. I would set the Parrot Bebop 2 camera to point downward as far as it can (and made sure I unchecked “look at grid center”), but when the mission began, it kept resetting to look at the grid center.

In any case, I’m just going to use a different drone. I have no issues using Pix4D, both fields and capture, with the Parrot Anafi.