How to get the principal point?

[ahmadkhajehnejad]

Hi there,

I need to have the principal point (the pixel location on with the camera is projected).
I computed focal length using this equation: focal length = H/2 * 1/(tan(FOV/2)).
I also have results['cam'] which are <scaling factor, tx, ty>.
I also have H and W. And also results['cam_trans'].