William A.P. Smith and Edwin R. Hancock Department of Computer Science, University of York, UK CVPR 2009 Reporter: Annie Lin

1. A unified model of specular and diffuse reflectance from microfacet model by describing both components of reflectance In terms of Fresnel theory and the same model of surface roughness. －－－ Parameter estimations that all have physical meaning. 2. Reflectance from surfaces 1. Surface Roughness model 3. A unified model 1. Masking and shadowing of microfacets 2. Fresnel reflectance 4. Specular reflectance 5. Diffuse reflectance

 If the illumination, viewer and normal direction vectors are specified in global coordinate

 Slope area distribution  [7] Torrance and Sparrow  Represent the number of facets per unit surface roughness

 The model requires only three physically meaningful parameters:  The refractive index of the surface ( )  The surface roughness ( )  The albedo of the surface ( )

 Masking and shadowing of microfacets  [5] Oren and Nayar  Fresnel reflectance  Fresnel’s equation:  Compute the proportion of light that is secularly reflected form the surface and that which enters the surface and is subsequently diffusely reflected

 Only those microfacets hose normal vectors lie within a solid angle dw ’ around the vector H, halfway between the light source and viewer, are capable of secularly reflecting light into the solid angle dw, around the view direction vector

 Radiance from a Lambertian patch  Diffuse radiance from a rough surface composed of shiny microfacets  the remaining proportion of the incident light  Account shadowing of the light source and Fresnel transmission into the surface

 Characteristics of the diffuse model

 The combination model: