空间变化材料外观的基于图像的重映射
Image-based remapping of spatially-varying material appearance
摘要：
BRDF模型是表示材料外观的普遍工具。然而，现在有大量不同的模型在实际使用中。在不同的渲染器中发现的实现之间缺乏BRDF模型标准化，以及各种模型通常在语义上不同的功能，已经成为不同渲染系统之间交换生产资产的主要障碍。目前解决这个问题的尝试依赖于手动查找模型之间的视觉相似性，或者它们的功能形状之间的数学相似性，这需要访问着色器实现，通常在商业渲染器中不可用。我们提出了一种方法，不同的BRDF模型之间的材料外观的自动翻译，它使用基于图像的度量外观比较，并代表与模型的渲染器的交互。我们分析了该方法的性能，无论是在鲁棒性和视觉差异的BRDF模型的多个组合的适合。虽然它对单个BRDF是有效的，但对于空间变化的BRDF，计算成本不能很好地扩展。因此，我们进一步提出了一个参数回归方案，近似的形状的变换函数，并生成一个减少表示立即评估，而无需进一步与渲染器的交互。我们提出了各自的视觉比较常用的渲染器和着色模型的重新映射的SVBRDF模型，并表明，我们的方法是能够外推变换BRDF参数比其他复杂的回归计划。
英文摘要：
BRDF models are ubiquitous tools for the representation of material appearance. However, there is now an astonishingly large number of different models in practical use. Both a lack of BRDF model standardisation across implementations found in different renderers, as well as the often semantically different capabilities of various models, have grown to be a major hindrance to the interchange of production assets between different rendering systems. Current attempts to solve this problem rely on manually finding visual similarities between models, or mathematical ones between their functional shapes, which requires access to the shader implementation, usually unavailable in commercial renderers. We present a method for automatic translation of material appearance between different BRDF models, which uses an image-based metric for appearance comparison, and that delegates the interaction with the model to the renderer. We analyse the performance of the method, both with respect to robustness and visual differences of the fits for multiple combinations of BRDF models. While it is effective for individual BRDFs, the computational cost does not scale well for spatially-varying BRDFs. Therefore, we further present a parametric regression scheme that approximates the shape of the transformation function and generates a reduced representation which evaluates instantly and without further interaction with the renderer. We present respective visual comparisons of the remapped SVBRDF models for commonly used renderers and shading models, and show that our approach is able to extrapolate transformed BRDF parameters better than other complex regression schemes.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
