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Summary: Illumination Decomposition for Material Recoloring
with Consistent Interreflections
Robert Carroll Ravi Ramamoorthi
University of California, Berkeley
Maneesh Agrawala
(a) Input (b) Modi ed Re ectance Only (c) Our Result: Modi ed Re ectance and Shading
Figure 1: We seek to recolor the input image (a). However, changing the color (reflectance) of the shirt alone, without modifying the
illumination, does not account for the correct diffuse reflection on the girl's arm or interreflections in the fine texture of the shirt (b). Indeed,
the image in (b) still has bluish reflections on the arm and a purple color shift on the shirt. Our user-assisted decomposition (Figure 2) lets
us modify indirect illumination to match the modified shirt color (c), leading to a much more consistent and natural looking recoloring.
Abstract
Changing the color of an object is a basic image editing operation,
but a high quality result must also preserve natural shading. A com-
mon approach is to first compute reflectance and illumination in-
trinsic images. Reflectances can then be edited independently, and
recomposed with the illumination. However, manipulating only
the reflectance color does not account for diffuse interreflections,
and can result in inconsistent shading in the edited image. We pro-
pose an approach for further decomposing illumination into direct
lighting, and indirect diffuse illumination from each material. This
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