Is it possible to get the normal of an area when I have all 4 corner points?

I try to get the normal of an area (a white paper) where I know in the current image all positions of the 4 corners? I want to know in which direction the arrow is pointing (or its rotations).

I managed to deskew the image, but now how to know the normal?


use solvePnP.

you need at least a decent estimate of the focal length of your camera, also the model points (know the size of that sheet of paper), and the corners in the picture, matched in order.