Camera intrinsic calibration

Hardware
1

Hi. I found the intrinsic parameters are not stable each time I calibrated. All the numbers will have small drift. I followed the tutorial for intrinsic calibration. May I know what might be the reason?
This is the industry provided calibration file.

image
image196×198 7.93 KB

I try to re-calibrate since I found when I try to do the extrinsic calibration of zed 2i with other sensors, the results are very unstable (opencv solvePnP will use camera matrix).
I used the recalibration tool twice and each time gives me a different result.
First time,
image
image298×193 11.2 KB

Second time,
image
image325×189 11.1 KB

I think I follow exactly the same process as the tutorial in the calibration tool. May I know the reason of this? And in this scenario, I do not think I can fully trust the initial calibration file. Then what is the best way to get a very accurate calibration result?

3

Hi @peppersaltyy
Manual calibration is normally affected by different environmental conditions:

  • light change
  • screen position
  • camera movements
  • temperature
  • noises

This is why we do not recommend performing a manual calibration unless strictly required (e.g., a damaged camera, underwater, or glass in front of the camera).

All the ZED cameras are factory calibrated in a calibration chamber with stable light and controlled temperature, using robotic arms that perform the same precise movements for each camera.

It is expected that different manual calibrations generate slightly different camera parameters.