Patent ID: 7589723

Claim:
A method for creating a set of parameter maps representing a surface of a partially translucent object, comprising: receiving data measuring reflectance and transmittance of light received at the surface of the partially translucent object; fitting a parametric model to the data; using the parametric model to generate the set of parameter maps for a computing system to render an image of the surface of the partially translucent object; gathering the reflectance data and the transmittance data from the surface including illuminating the surface with a uniform diffuse area light source; measuring a specular intensity for each of a plurality of points across the surface; wherein the parametric model includes: a bidirectional reflectance distribution function including: a diffuse reflectance term dependent on spatial position relative to the surface; and a glossy term dependent on spatial position relative to the surface and angles of incidence and reflectance of at least one light source; and a bidirectional transmittance distribution function including a diffuse transmittance term depending on spatial position relative to the surface; wherein the data includes at least one of: a diffuse reflectance; a specular intensity; a specular roughness; and a transmittance; calculating from the diffuse reflectance, the transmittance, and an estimated thickness: an absorption coefficient; and a scattering coefficient; wherein the parameter maps include at least one of: an albedo map derived from the glossy term of the bidirectional reflectance distribution function, the absorption coefficient, and the scattering coefficient; a local thickness variation map derived from the bidirectional transmittance distribution function, the absorption coefficient and the scattering coefficient; a specular roughness map derived from the data measured; and a specular intensity map derived from the diffuse term of the bidirectional reflectance distribution function, the specular roughness map and the data measured from the surface; and wherein the parameter maps are stored in a pair of red-green-blue-alpha textures, wherein: the albedo map is stored in red-green-blue channels of a first texture; the specular intensity map is stored in red-green-blue channels of a second texture; the specular roughness map is stored in an alpha channel of one of the first texture and the second texture; and the local thickness variation map is stored in an opposite alpha channel in one of the first texture and the second texture in which the specular roughness map is not stored.