Authors:
Kei Iwasaki
1
;
Yoshinori Dobashi
2
;
Fujiichi Yoshimoto
3
and
Tomoyuki Nishita
3
Affiliations:
1
Wakayama University; Hokkaido University, Japan
;
2
Wakayama University, Hokkaido University, Japan
;
3
Wakayama University, The University of Tokyo, Japan
Keyword(s):
BRDF(Bidirectional Reflectance Distribution Function), Material Editing, Inverse Problem, Image-based Lighting.
Related
Ontology
Subjects/Areas/Topics:
Computer Vision, Visualization and Computer Graphics
;
Image-Based Rendering
;
Lighting and Appearance
;
Real-Time Rendering
;
Rendering
Abstract:
This paper presents a BRDF modeling method, based on an inverse problem approach. Our method calculates BRDFs to match the appearance of the object specified by the user. By representing BRDFs by a linear combination of basis functions, outgoing radiances of the object surface can be represented using basis functions. The calculation of the desired BRDF results from calculating the corresponding coefficients of basis functions that minimize the sum of differences between the outgoing radiances, represented using basis functions and
user specified radiances. The properties that BRDFs must satisfy are described by linear constraint conditions. This minimization problem can be solved, interactively, using a linearly constrained least squares approach. Thus, our method allows the user to design BRDFs directly, under fixed complex lighting and viewpoint, and to view the rendering results interactively, under dynamic lighting and viewpoint.