Symmetric photography: exploiting data-sparseness in reflectance fields
Symmetric photography: exploiting data-sparseness in reflectance fields
复制标题
DOI：
10.2312/egwr/egsr06/251-262
复制
发表时间：
2006-06
期刊：
影响因子：
--
通讯作者：
Gaurav Garg;Eino-Ville Talvala;M. Levoy;H. Lensch
中科院分区：
文献类型：
--
作者：
Gaurav Garg;Eino-Ville Talvala;M. Levoy;H. Lensch
我们提出了一种称为对称摄影的新技术来捕捉真实世界的反射率场。该技术将8D反射率场建模为4D入射光场和4D激发光场之间的传输矩阵。由于输运矩阵的大小，获取输运矩阵是一项具有挑战性的任务。幸运的是，传输矩阵是对称的，并且通常是数据稀疏的。对称性使我们能够同时从两个侧面测量光的传输，从照明方向和观察方向。数据稀疏性是指可以使用低阶表示很好地近似矩阵的子块的事实。我们引入分层张量作为底层数据结构来捕捉这种数据稀疏性，特别是通过传输矩阵的局部秩1分解。除了提供用于存储的有效表示之外，它还允许快速获取近似传输矩阵并从捕获的矩阵快速绘制图像。我们的原型采集系统由一组反射镜和一对同轴投影仪和摄像机组成。我们用我们的系统捕获的反射率场渲染的场景来演示我们系统的有效性。在这些渲染中，我们可以更改视点，也可以使用任意入射光场重新照明。
We present a novel technique called symmetric photography to capture real world reflectance fields. The technique models the 8D reflectance field as a transport matrix between the 4D incident light field and the 4D exitant light field. It is a challenging task to acquire this transport matrix due to its large size. Fortunately, the transport matrix is symmetric and often data-sparse. Symmetry enables us to measure the light transport from two sides simultaneously, from the illumination directions and the view directions. Data-sparseness refers to the fact that sub-blocks of the matrix can be well approximated using low-rank representations. We introduce the use of hierarchical tensors as the underlying data structure to capture this data-sparseness, specifically through local rank-1 factorizations of the transport matrix. Besides providing an efficient representation for storage, it enables fast acquisition of the approximated transport matrix and fast rendering of images from the captured matrix. Our prototype acquisition system consists of an array of mirrors and a pair of coaxial projector and camera. We demonstrate the effectiveness of our system with scenes rendered from reflectance fields that were captured by our system. In these renderings we can change the viewpoint as well as relight using arbitrary incident light fields.