Manipulating Shape and Material of Bidirectional Texture Functions

• Main Authors: Sung-Hsiang Chao, 趙崧翔
• Other Authors: 歐陽明
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/77612044340582207485

碩士 === 國立臺灣大學 === 資訊工程學研究所 === 93 === Currently, realistic rendering of complex materials in real-time is still a big challenge. Many graphics researchers have devoted to study representations of real-world materials for better rendering quality. The most critical issue is that: it is hard to separate the intermixed shading of complex materials, which is generated by surface meso-structure and reflectance. In this thesis, a method is presented to manipulate shape and reflectance of bidirectional texture functions (BTFs), which is a general representation of complex materials. We first separate a BTF into shape (surface meso-structure, or a normal map in practice) and reflectance (bidirectional reflectance distribution functions, BRDFs). Furthermore, we can manipulate the shape and reflectance to create new synthesized materials. Two phases are employed to achieve our objective. First, assuming that the reflectance of every pixel in a BTF behaves independently, we recover the per-pixel normal and BRDF parameters based on photometric stereo. Afterwards, we provide a friendly user interface and several operations to manipulate the recovered shape and reflectance to produce numerous plausible materials. In consideration of cost of the acquisition a real BTF, our work provides an alternative method for generation of complex material.