Improved viewpoint entropy to evaluate material appearance under various lighting positions
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In this paper, we proposed a useful calculation method to perform the perception-based selection of lighting position that emphasizes the material appearance of CG object. The proposed method is based on the conventional viewpoint entropy which is used to find an appropriate viewing angle. To find an appropriate shot for material appearance, we first identified the important surface that has information of gloss reflection related to material appearance with eye tracking equipment. Next, we modified the equation of viewpoint entropy by adding a weight coefficient for emphasizing at important surface. Since this viewpoint entropy retains the independency for object shape, light direction, and viewing direction, our proposed method can extract only important light position which is most representative of the material appearance. From the results of verification with changing shape and material of CG object, we confirmed that our selection of lighting position accomplishes the fine agreement with subjective evaluation which is imposed on the selection of appropriate scene with emphasis of material appearance.
KeywordsVisual entropy Gloss Material appearance Computer graphics
This research was partially supported by the Ministry of Education, Science, Sports and Culture, Japan Grant-in-Aid for Scientific Research, Brain and Information Science on SHITSUKAN, 23135530 (2012), 25135707 (2013), and Grant-in-Aid for Scientific Research(C), 15K00415 (2015), respectively.
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