Conference paper
Addressing Grazing Angle Reflections in Phong Models
The Phong illumination model is used extensively as it is simple with few parameters. It is however often challenging to fit such a single lobed model to the bidirectional reflectance distribution function (BRDF) of a real material, especially at grazing angles (Fig. 1). The fitting issues are in shortcomings of the model, in choosing error function, and in initial guess sensitivity [Matusik et al. 2003].
In previous work [Ngan et al. 2005], these issues were bypassed by using two specular lobes, by ignoring very grazing angles (>80°), and, in cases of unsatisfactory fitting quality, by manually restarting the fitting procedure with a different initial guess. In this work, we also fit Phong models to the BRDFs measured by Matusik et al. [2003], but we focus on the difficult grazing angles.
Our result is a new Phong variant that fits better to a broader range of materials, and, for this model, we address the above-mentioned fitting issues.
Language: | English |
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Publisher: | Association for Computing Machinery |
Year: | 2014 |
Pages: | 1-1 |
Proceedings: | 7th ACM SIGGRAPH Conference and Exhibition on Computer Graphics and Interactive Techniques in Asia (SIGGRAPH ASIA '14)International Conference on Computer Graphics and Interactive Techniques |
ISBN: | 1450327923 and 9781450327923 |
Types: | Conference paper |
DOI: | 10.1145/2668975.2668979 |
ORCIDs: | Frisvad, Jeppe Revall , Conradsen, Knut and Aanæs, Henrik |