Different outputs with same inputs

PIX4Dmapper PIX4Dmapper Questions/Troubleshooting
1

I am trying to use some older drone imager for mapping. This wasn’t taken with the best practices or Pix4D stitching in mind, but it is not possible to refly the survey. I need to maximize the quality of the stitch with this imagery as best I can.

I have noticed that I can run initial processing, then, without clicking anything or changing anything about the inputs, I can run initial processing again and get a totally different output. I have attached four quality reports; all of these are from the exact same inputs. As you can see, the GCP error ranges from 0.001 to 21 meters. The Computed Image/GCPs/Manual Tie Points Position look extremely different across the different runs.

I have noticed that while re running initial processing can result in really different maps, just hitting rematch and reoptimize does not change the outcome signficantly. I have three questions:

  1. what is the difference between rematch and reoptimize and re running initial processing?

  2. I am assuming that these differences are resulting from some sort of random seed process at the beginning of initial processing. What is that process? Where can I get info about the non-deterministic modeling in Pix4D?

  3. Can I trust a "good’ run if I’m getting a map that looks correct and for which the error calculation is relatively low?

Thanks!
20210129 ANM Stitch_report1.pdf (140.2 KB)
20210129 ANM Stitch_report.pdf (726.6 KB)
20210129 ANM Stitch_report3.pdf (159.2 KB)
20210129 ANM Stitch_report2.pdf (319.3 KB)

2

Hello @momcente, I can see that you have been using different processing option such as image scale and so on. As your project has single flight lines, the behavior that you are seeing is expected while changing the processing option. So, here are the recommendation for processing the project.

  1. Use full images scale not 1/4.
  2. Don’t use alot of mtps. Try to use the ones in the area you are seeing the issue such as blocks.

However, the most important recommendation anyone can give for this project is recapturing the images with good overlap and having continuous images captures.

Regarding the information about Rematch and reoptimize, visit the below link