Polynomial Texture Maps

Malzbender, Tom ; Gelb, Dan ; Wolters, Hans

HP Development Company

关键词: graphics hardware;    illumination;    image processing;    image-based rendering;    reflectance & shading models;    texture mapping;   

RP-ID  :  HPL-2001-33R1

学科分类：计算机科学（综合）

美国|英语

来源: HP Labs

【 摘 要 】

In this paper we present a new form of texture mapping that produces increased photorealism. Coefficients of a biquadratic polynomial are stored per texel, and used to reconstruct the surface color under varying lighting conditions. Like bump mapping, this allows the perception of surface deformations. However, our method is image based, and photographs of a surface under varying lighting conditions can be used to construct these maps. Unlike bump maps, these Polynomial Texture Maps (PTMs) also capture variations due to surface self-shadowing and interreflections, which enhance realism. Surface colors can be efficiently reconstructed from polynomial coefficients and light directions with minimal fixed-point hardware. We have also found PTMs useful for producing a number of other effects such as anisotropic and Fresnel shading models and variable depth of focus. Lastly, we present several reflectance function transformations that act as contrast enhancement operators. We have found these particularly useful in the study of ancient archeological clay and stone writings. Notes: Copyright ACM. To be published in and presented at ACM SIGGRAPH 2001 held in Los Angeles, CA, August 12-17, 2001. 10 Pages