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A unified model of specular and diffuse reflectance for rough, glossy surfaces

A unified model of specular and diffuse reflectance for rough, glossy surfaces. William A.P. Smith and Edwin R. Hancock Department of Computer Science, University of York, UK CVPR 2009 Reporter: Annie Lin . Introduction.

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A unified model of specular and diffuse reflectance for rough, glossy surfaces

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  1. A unified model of specular and diffuse reflectance for rough, glossy surfaces William A.P. Smith and Edwin R. Hancock Department of Computer Science, University of York, UK CVPR 2009 Reporter: Annie Lin

  2. Introduction • 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. • Reflectance from surfaces • Surface Roughness model • A unified model • Masking and shadowing of microfacets • Fresnel reflectance • Specular reflectance • Diffuse reflectance

  3. Reflectance from surfaces • If the illumination, viewer and normal direction vectors are specified in global coordinate

  4. Surface Roughness model • Slope area distribution • [7] Torrance and Sparrow • Represent the number of facets per unit surface roughness

  5. A unified model • The model requires only three physically meaningful parameters: • The refractive index of the surface ( ) • The surface roughness ( ) • The albedo of the surface ( )

  6. 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

  7. Specular reflectance • Only those microfacets hose normal vectors lie within a solid angledw’ 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

  8. Diffuse reflectance • 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

  9. Characteristics of the diffuse model

  10. Experiments • The combination model:

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