  We present Zero-NeRF, a projective surface registration method that, to the
best of our knowledge, offers the first general solution capable of alignment
between scene representations with minimal or zero visual correspondence. To do
this, we enforce consistency between visible surfaces of partial and complete
reconstructions, which allows us to constrain occluded geometry. We use a NeRF
as our surface representation and the NeRF rendering pipeline to perform this
alignment. To demonstrate the efficacy of our method, we register real-world
scenes from opposite sides with infinitesimal overlaps that cannot be
accurately registered using prior methods, and we compare these results against
widely used registration methods.
