[NOT A BUG] Locked XMP calib - Recon with random translation

Development Asset Creation
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I have been using XMP files without issues with 8 precalibrated machine vision cameras. So, I know how to create proper XMP files.

I’m now trying a new setup, with 7 Canon DSLR cameras, still computing my own calibration and generating XMP files.

However, now the reconstructions have a random rigid transform added up, mostly a translation.

Using F5 (Create reconstruction using input) multiple times results in reconstructions with quite large coordinate system differences.

This doesn’t happen with my other 8 camera setup. The reconstruction noise changes but surfaces remain in perfect registration.

Attached is a screen shot showing two subsequent F5 calls with prior pose & calibration locked.

Everything seems fine but the exported meshes have a 1 cm translation difference as can be seen in the meshlab screenshot.

The expected results would be near perfect alignment since I’m using the same locked XMP files for both reconstructions.

I repeated this experiment over and over, the differences can reach 5 cm.

Also the scene viewer inside RealityCapture has very different coordinate system for the two components. This doesn’t occur for my other XMP setup.

I attached the XMP files. I can send you a link for the full dataset (700 MB) in a private email.

Thanks,
Mathieu

2

Hi Mathieu Lamarre

In the dataset where you created the XMPs, you need to set local1: euclidean system before alignment ( it’s a default setting but just to be sure )

when you create XMPs and reuse them, they are in local1: euclidean system and that’s OK, BUT when you export from RC and you set a GRID PLANE, you then get the position issue…

if you use a secondary project, you can export with PROJECT OUTPUT COORDINATE SYSTEM or GRID PLANE.
Use the PROJECT OUTPUT COORDINATE SYSTEM to get perfectly calibrated XMPs

So in short:

  1. create XMPs but DO NOT calculate the model,
  2. export the XMPs,
  3. use these XMPs for the SAME dataset - so you realign it with XMPs,
  4. choose the option to export with the PROJECT OUTPUT COORDINATE SYSTEM,
  5. all models will be at the same position…
3

Thanks that solved my issue! You can close this report.

We create the XMPs with a Python script from another calibration format. The “Project ouput” coordinate system options was always there in the Export Model dialog (never noticed it). Selected it and it worked perfectly.

Attached is screen shot to help others.