An Approximate Shading Model with Detail Decomposition for Object Relighting
This work addresses the challenge of making inserted objects appear naturally lit in target scenes for artists and image editors, representing an incremental improvement over existing methods.
The paper tackles the problem of object relighting for image compositing by proposing an approximate shading model that decomposes shading into rough shape, parametric shading detail, and geometric detail terms, enabling more flexible compositing than image-based methods, with quantitative evaluation and user studies indicating it is a promising alternative.
We present an object relighting system that allows an artist to select an object from an image and insert it into a target scene. Through simple interactions, the system can adjust illumination on the inserted object so that it appears naturally in the scene. To support image-based relighting, we build object model from the image, and propose a \emph{perceptually-inspired} approximate shading model for the relighting. It decomposes the shading field into (a) a rough shape term that can be reshaded, (b) a parametric shading detail that encodes missing features from the first term, and (c) a geometric detail term that captures fine-scale material properties. With this decomposition, the shading model combines 3D rendering and image-based composition and allows more flexible compositing than image-based methods. Quantitative evaluation and a set of user studies suggest our method is a promising alternative to existing methods of object insertion.