LightIt: Illumination Modeling and Control for Diffusion Models
Authors: name: Peter Kocsis, name: Julien Philip, name: Kalyan Sunkavalli, name: Matthias Nießner, name: Yannick Hold-Geoffroy

We introduce LightIt, a method for explicit illumination control for image
generation. Recent generative methods lack lighting control, which is crucial
to numerous artistic aspects of image generation such as setting the overall
mood or cinematic appearance. To overcome these limitations, we propose to
condition the generation on shading and normal maps. We model the lighting with
single bounce shading, which includes cast shadows. We first train a shading
estimation module to generate a dataset of real-world images and shading pairs.
Then, we train a control network using the estimated shading and normals as
input. Our method demonstrates high-quality image generation and lighting
control in numerous scenes. Additionally, we use our generated dataset to train
an identity-preserving relighting model, conditioned on an image and a target
shading. Our method is the first that enables the generation of images with
controllable, consistent lighting and performs on par with specialized
relighting state-of-the-art methods.