Mixture of Spherical Distributions for Single-View Relighting
Mixture of Spherical Distributions for Single-View Relighting
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DOI：
10.1109/tpami.2007.1164
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发表时间：
2008
影响因子：
23.6
通讯作者：
Kenji Hara;K. Nishino;K. Ikeuchi
中科院分区：
文献类型：
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作者：
Kenji Hara;K. Nishino;K. Ikeuchi
我们提出了一种方法，同时估计照明的场景和反射特性的对象从单视图图像-一个单一的图像或少量的图像从同一个观点。我们假设照明由多个点光源组成，并且物体的形状是已知的。首先，我们表示一个单位球的表面上的照明作为一个有限的混合冯Mises-Fisher分布的基础上一个新的球面镜面反射模型，以及近似的Torrance-Sparrow反射模型。接下来，我们估计这个混合模型的参数，包括其组件分布的数量和它们的标准偏差，分别对应于光源的数量和表面粗糙度。最后，使用这些结果作为初始估计，我们迭代地完善基于原始Torrance-Sparrow反射模型的估计。最终的估计可以用于重新照亮单视图图像，例如改变各个光源的强度和方向。该方法提供了一个统一的框架，同时估计未知数量的光源的强度和方向的方向统计的基础上，以及在场景中的物体的镜面反射参数。
We present a method for simultaneously estimating the illumination of a scene and the reflectance property of an object from single view images-a single image or a small number of images taken from the same viewpoint. We assume that the illumination consists of multiple point light sources, and the shape of the object is known. First, we represent the illumination on the surface of a unit sphere as a finite mixture of von Mises-Fisher distributions based on a novel spherical specular reflection model that well approximates the Torrance-Sparrow reflection model. Next, we estimate the parameters of this mixture model including the number of its component distributions and the standard deviation of them, which correspond to the number of light sources and the surface roughness, respectively. Finally, using these results as the initial estimates, we iteratively refine the estimates based on the original Torrance-Sparrow reflection model. The final estimates can be used to relight single-view images such as altering the intensities and directions of the individual light sources. The proposed method provides a unified framework based on directional statistics for simultaneously estimating the intensities and directions of an unknown number of light sources, as well as the specular reflection parameter of the object in the scene.