Refined sensor model

Hello everyone,
the RefineSensormodel application does not allow to calculate the checkpoints error. For this reason I would like to understand how to interpret the 5 parameters of the affine transformation that I read in the statistics file. Should they be applied to the image coordinates or to the map coordinates? In particular, what does sigma=50 mean?
Thank you

Those parameters actually come from OSSIM, you can see here how they are used. Regarding the sigmas parameters, I doubt OTB uses them.

Thanks for the support, your response is very helpful.
I am trying to derive the coordinates called “predicted_lon and predicted_lat” in the geom file exported from the RefineSensorModel application by flagging Output file containing output precision statistics. Can you help me?
Best regards