We introduce a novel parametric BRDF model that can
accurately encode a wide variety of real-world isotropic
BRDFs with a small number of parameters. The key observation
we make is that a BRDF may be viewed as a statistical
distribution on a unit hemisphere. We derive a novel
directional statistics distribution, which we refer to as the
hemispherical exponential power distribution, and model an
isotropic BRDF with a mixture of it. The novel directional
statistics BRDF model allows us to derive a canonical probabilistic
method for estimating its parameters including the
number of components. We show that the model captures
the full spectrum of real-world isotropic BRDFs with accuracy
comparable to non-parametric models but with a much
more compact representation. We also experimentally show
that the model achieves better accuracy with less measurements
compared with such non-parametric models. We further
demonstrate the advantages of the novel BRDF model
by showing its ...