What are the differences between posest's pe::PoseEstimator2d  and
pe::PoseEstimator3d? Which one should be used for a monocular camera? I
believe PoseEstimator2d  is based on the SFM method (Structure from Motion).
For some reason, I get results only with stereo images and PoseEstimator3d.
Does any one have any example of posest for a monocular camera?

Thank you all!

Carlos