How to convert camera parameters to OpenCV format?

[DWendou]

How to calculate K and D in OpenCV internal parameter format based on polynomial coefficents and stretch matrix？

[GuicarMIS]

Hi @DWendou,
With @EvaGoichon, we are going to publish a paper at ICRA 2024 on the topic of conversion between camera models and we share the code at: https://github.com/PerceptionRobotique/libPeR_base (see the examples *CameraModelConversion).

We did not do (yet) the conversion of the Cartesian Polynomial model (OCamCalib's model) to OpenCV's versions of the Kannala-Brandt model (nor the perspective with Rational Polynomial distorsions model but I guess it is the fisheye one you are interested in?) and it is not our priority now. If you are in a hurry, I think you can take inspiration of our methods to make it yourself (and if you are stuck, we can have a look together if you want).