Apparatus and method for performing lighting calculations for surfaces of three-dimensional objects
First Claim
1. Apparatus for processing image data representing three-dimensional objects in order to perform lighting calculations for a surface of one of said objects with reference to a light source, said surface having a degree of diffuse reflectivity defined by a diffuse reflectivity coefficient and a degree of specular reflectivity defined by a specular reflectivity coefficient, said apparatus comprising:
- means for defining a vector normal to the surface as a surface normal vector;
means for defining a vector directed between the surface and the light source as a light source vector;
means for combining the surface normal vector and the light source vector to form a scalar product thereof;
calculating means for calculating from said scalar product, without reference to a view position, a lighting value for the surface including (i) a diffuse lighting component dependent upon the diffuse reflectivity coefficient and (ii) a specular lighting component dependent upon the specular reflectivity coefficient, said specular component being a non-linear function of said scalar product.
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Accused Products
Abstract
Image data representing multi-dimensional objects are processed by calculating lighting characteristics in response to lighting parameters of surfaces and the parameters of light sources.
Surface highlight characteristics are produced by a non-linear process. However, the non-linear process is performed without reference to a view position.
Processing highlight characteristics without reference to the view position allows characteristics to be produced without transforming the view position and without calculating additional vectors.
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Citations
42 Claims
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1. Apparatus for processing image data representing three-dimensional objects in order to perform lighting calculations for a surface of one of said objects with reference to a light source, said surface having a degree of diffuse reflectivity defined by a diffuse reflectivity coefficient and a degree of specular reflectivity defined by a specular reflectivity coefficient, said apparatus comprising:
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means for defining a vector normal to the surface as a surface normal vector; means for defining a vector directed between the surface and the light source as a light source vector; means for combining the surface normal vector and the light source vector to form a scalar product thereof; calculating means for calculating from said scalar product, without reference to a view position, a lighting value for the surface including (i) a diffuse lighting component dependent upon the diffuse reflectivity coefficient and (ii) a specular lighting component dependent upon the specular reflectivity coefficient, said specular component being a non-linear function of said scalar product. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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13. In an image processing apparatus having a processor for processing signals defining three-dimensional objects, a method of processing the signals to perform lighting calculations for a surface of one of said objects with reference to a light source, said surface having a degree of diffuse reflectivity defined by a diffuse reflectivity coefficient and a degree of specular reflectivity defined by a specular reflectivity coefficient, said method comprising the steps of:
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defining a vector normal to the surface as a surface normal vector; defining a vector directed between the surface and the light source as a light source vector; combining the surface normal vector and the light source vector to form a scalar product thereof; calculating from said scalar product, without reference to a view position, a lighting value for the surface including (i) a diffuse lighting component dependent upon the diffuse reflectivity coefficient and (ii) a specular lighting component dependent upon the specular reflectivity coefficient, said specular component being a non-linear function of said scalar product. - View Dependent Claims (14, 15)
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28. A computer usable medium having computer readable instruction code means stored therein for causing a computer to process signals defining three dimensional objects to perform lighting calculations for a surface of one of said objects with reference to a light source, said surface having a degree of diffuse reflectivity defined by a diffuse reflectivity coefficient and a degree of specular reflectivity defined by a specular reflectivity coefficient, comprising:
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computer readable instruction code means for causing the computer to define a vector normal to the surface as a surface normal vector; computer readable instruction code means for causing the computer to define a vector directed between the surface and the light source as a light source vector; computer readable instruction code means for causing the computer to combine the surface normal vector and the light source vector to form a scalar product thereof; and computer readable instruction code means for causing the computer to calculate from said scalar product, without reference to a view position, a lighting value for the surface including (i) a diffuse lighting component dependent upon the diffuse reflectivity coefficient and (ii) a specular lighting component dependent upon the specular reflectivity coefficient, said specular component being a non-linear function of said scalar product. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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Specification