图像驱动的三维模型外观细节增强

随着计算机游戏与电影视觉特效的普及应用，仅通过纹理贴图已不能满足用户需求。然而，为三维模型制作视觉真实的表面外观，即在包含几何细节变化(如金属腐蚀、石料风化、木质裂纹等)同时辅之以与几何变化合理匹配的材质颜色却是一件困难且耗时的工作。文章提出了一种能够从单幅图像中提取物体的外观细节(材质与几何信息)并增强至三维模型表面的方法。该方法是一种新型的几何约束的非刚性2D-3D融合配准算法，可以通过将配准后的模型提供的几何信息作为先验知识实现更好的本征图像分解结果。利用图像中同步分解出的互相关的多尺度几何信息与材质纹理信息组成的非参数外观模型，文中提出了一种法向量约束的几何变形算法将外观纹理恢复到代理模型上。通过上述步骤，文章提出的方法能够帮助建模师制作具有多尺度外观细节的三维模型。

Image-Driven Appearance Detail Enhancement on 3D Shape

Modeling 3D objects with realistic surface appearance is a challenging and time-demanding task. While a rough approximation of the overall object shape can be quickly modeled by an experienced modeler, or retrieved from a shape repository, endowing a 3D shape with realistic surface appearance, consisting of spatially variant ifne scale geometric detail and relfectance, can be extremely time consuming. In this paper, a method that allows modelers to quickly extract a non-parametric appearance model from a single photograph and to easily apply it on various 3D shapes was presented. The extraction was assisted by a user-provided proxy, whose geometry roughly approximates that of the object in the image. A novel technique was used to align and deform the proxy shape so as to match the reference object, thereby enabling accurate joint recovery of geometric detail and relfectance. The correlations between the recovered geometry at various scales and the spatially varying appearance constitute a non-parametric model. The extracted appearance model can then be easily applied to the proxy by our normal transfer algorithm, greatly assisting in modeling detailed and realistic 3D models.