We propose a generalization of example-based texture synthesis to spatio-temporal BRDFs. A key component of our method is a novel representation of time-varying materials using polynomials describing time-varying BRDF parameters. Our representation allows efficient fitting of measured data into a compact spatio-temporal BRDF representation, and it allows an efficient analytical evaluation of distances between spatio-temporal BRDF parameters. We show that even polynomials of low degree are sufficient to represent various time-varying phenomena and provide more accurate results than the previously proposed representation. We are the first who applied the example-based texture synthesis on abstract structures such as polynomial functions. We present two applications of synthesizing spatio-temporal BRDFs using our method: material enlargement and transfer of time-varying phenomenon from an example to a given static material. We evaluated the synthesized BRDFs in the context of realistic rendering and real-time rendering.

我们提出了基于实例的纹理合成对时空BRDF的一般化。我们方法的关键部分是使用描述时变BRDF参数的多项式来表示时变材料。我们的表示允许将测量数据高效地拟合为紧凑的时空BRDF表示形式，并且可以对时空BRDF参数之间的距离进行有效的分析评估。我们表明，即使是低阶多项式也足以表示各种时变现象，并且比以前提出的表示形式提供了更准确的结果。我们是第一个将基于示例的纹理合成应用于诸如多项式函数之类的抽象结构的人。我们介绍了使用我们的方法合成时空BRDF的两个应用：从实例到给定的静态材料的材料扩展和时变现象的转移。我们在逼真的渲染和实时渲染的背景下评估了合成的BRDF。