I know that one can compute the homography matrix by using at least four correpondence points.
I was wondering if and how can I obtain a homography matrix if I already know the rotation and translation between two cameras, including the camera intrinsics?
I found something that looked like this
H= KRK^-1
but this assumes a pure rotation. What would be the case for a pure translation? And what if I want to warp an image with the homography matrix that is not from points purely on a plane?
I'm somewhat confused right now and would really really appreciate any explanations! Thank you in advance!
If there is a nonzero translation, and the image contains more than a plane (or you are not looking at very far away things) then the images are not related by a homography. You can convince yourself that this is the case by noticing that some points visible in one image may be occluded in the other one.
If the image shows a plane among other things, and you estimate a homography using only point correspondences on that plane, than the homography will correctly transform all points on that plane, but will map incorrectly all other points.