To learn from monocular videos with dynamically de-
forming faces, the mapping from pixels to 3D locations on
the canonical surface is required. To this end, we aug-
ment the root-ﬁnding algorithm from SNARF [12] with a
ray marcher akin to that of IDR [69], yielding the canonical
surface correspondence for each pixel. The color predic-
tion for each image location is then given by the canonical
texture network, which formulates our primary source of
supervision: a per-pixel image reconstruction objective.
I M Avatar- Implicit Morphable Head Avatars from Videos