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Published byWinston Sharper Modified over 10 years ago
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William A.P. Smith and Edwin R. Hancock Department of Computer Science, University of York, UK CVPR 2009 Reporter: Annie Lin
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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
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If the illumination, viewer and normal direction vectors are specified in global coordinate
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Slope area distribution [7] Torrance and Sparrow Represent the number of facets per unit surface roughness
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The model requires only three physically meaningful parameters: The refractive index of the surface ( ) The surface roughness ( ) The albedo of the surface ( )
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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
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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
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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
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Characteristics of the diffuse model
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The combination model:
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