  We present a novel approach to single-view face relighting in the wild.
Handling non-diffuse effects, such as global illumination or cast shadows, has
long been a challenge in face relighting. Prior work often assumes Lambertian
surfaces, simplified lighting models or involves estimating 3D shape, albedo,
or a shadow map. This estimation, however, is error-prone and requires many
training examples with lighting ground truth to generalize well. Our work
bypasses the need for accurate estimation of intrinsic components and can be
trained solely on 2D images without any light stage data, multi-view images, or
lighting ground truth. Our key idea is to leverage a conditional diffusion
implicit model (DDIM) for decoding a disentangled light encoding along with
other encodings related to 3D shape and facial identity inferred from
off-the-shelf estimators. We also propose a novel conditioning technique that
eases the modeling of the complex interaction between light and geometry by
using a rendered shading reference to spatially modulate the DDIM. We achieve
state-of-the-art performance on standard benchmark Multi-PIE and can
photorealistically relight in-the-wild images. Please visit our page:
https://diffusion-face-relighting.github.io
