%0 Conference Paper %1 Oren:Nayar:1994 %A Oren, Michael %A Nayar, Shree K. %B Proceedings of the 21st Annual Conference on Computer Graphics and Interactive Techniques %C New York, NY, USA %D 1994 %I ACM %K brdf microfacet %P 239--246 %R 10.1145/192161.192213 %T Generalization of Lambert's Reflectance Model %X Lambert's model for body reflection is widely used in computer graphics. It is used extensively by rendering techniques such as radiosity and ray tracing. For several real-world objects, however, Lambert's model can prove to be a very inaccurate approximation to the body reflectance. While the brightness of a Lambertian surface is independent of viewing direction, that of a rough surface increases as the viewing direction approaches the light source direction. In this paper, a comprehensive model is developed that predicts body reflectance from rough surfaces. The surface is modeled as a collection of Lambertian facets. It is shown that such a surface is inherently non-Lambertian due to the foreshortening of the surface facets. Further, the model accounts for complex geometric and radiometric phenomena such as masking, shadowing, and interreflections between facets. Several experiments have been conducted on samples of rough diffuse surfaces, such as, plaster, sand, clay, and cloth. All these surface demonstrate significant deviation from Lambertian behavior. The reflectance measurements obtained are in strong agreement with the reflectance predicted by the model. %@ 0-89791-667-0

@inproceedings{Oren:Nayar:1994, abstract = {Lambert's model for body reflection is widely used in computer graphics. It is used extensively by rendering techniques such as radiosity and ray tracing. For several real-world objects, however, Lambert's model can prove to be a very inaccurate approximation to the body reflectance. While the brightness of a Lambertian surface is independent of viewing direction, that of a rough surface increases as the viewing direction approaches the light source direction. In this paper, a comprehensive model is developed that predicts body reflectance from rough surfaces. The surface is modeled as a collection of Lambertian facets. It is shown that such a surface is inherently non-Lambertian due to the foreshortening of the surface facets. Further, the model accounts for complex geometric and radiometric phenomena such as masking, shadowing, and interreflections between facets. Several experiments have been conducted on samples of rough diffuse surfaces, such as, plaster, sand, clay, and cloth. All these surface demonstrate significant deviation from Lambertian behavior. The reflectance measurements obtained are in strong agreement with the reflectance predicted by the model.}, acmid = {192213}, added-at = {2015-12-07T11:25:20.000+0100}, address = {New York, NY, USA}, author = {Oren, Michael and Nayar, Shree K.}, biburl = {https://www.bibsonomy.org/bibtex/261a797b62adaab9b67e1229badab83fd/ledood}, booktitle = {Proceedings of the 21st Annual Conference on Computer Graphics and Interactive Techniques}, description = {Generalization of Lambert's reflectance model}, doi = {10.1145/192161.192213}, interhash = {de51ba49ff92a947073a2c653bb2fb92}, intrahash = {61a797b62adaab9b67e1229badab83fd}, isbn = {0-89791-667-0}, keywords = {brdf microfacet}, numpages = {8}, pages = {239--246}, publisher = {ACM}, series = {SIGGRAPH '94}, timestamp = {2016-04-29T15:28:03.000+0200}, title = {Generalization of Lambert's Reflectance Model}, year = 1994 }