We address the problem of instance-level facial attribute transfer without
paired training data, e.g. faithfully transferring the exact mustache from a
source face to a target face. This is a more challenging task than the
conventional semantic-level attribute transfer, which only preserves the
generic attribute style instead of instance-level traits. We propose the use of
geometry-aware flow, which serves as a well-suited representation for modeling
the transformation between instance-level facial attributes. Specifically, we
leverage the facial landmarks as the geometric guidance to learn the
differentiable flows automatically, despite of the large pose gap existed.
Geometry-aware flow is able to warp the source face attribute into the target
face context and generate a warp-and-blend result. To compensate for the
potential appearance gap between source and target faces, we propose a
hallucination sub-network that produces an appearance residual to further
refine the warp-and-blend result. Finally, a cycle-consistency framework
consisting of both attribute transfer module and attribute removal module is
designed, so that abundant unpaired face images can be used as training data.
Extensive evaluations validate the capability of our approach in transferring
instance-level facial attributes faithfully across large pose and appearance
gaps. Thanks to the flow representation, our approach can readily be applied to
generate realistic details on high-resolution images.

本篇论文提出了一种基于几何感知流表征的面部特征无对应数据实例级转移方法，配合外推网络和循环一致性框架可以实现跨大姿态和外貌差异的高保真面部特征转移。