Development of a Fast Method for Generating Computer Animation Using a Isophotic Morphing

这个项目开发了一种快速的方法来生成逼真的动画，考虑到改变光源位置时光的相互反射。该方法预先考虑光的互反射，计算多个采样光源位置的照度分布，并将分布存储为等同光线。指定新光源位置后，通过翘曲等同线插值光源位置处的照度分布。由于该方法对等同线的位置和形状使用了变形技术，因此该方法可以插值与光源位置有关的非线性照度分布。为了提高光照变形方法的精度，将所得图像与传统的线性插值方法进行了比较，提出了光照变形与线性插值相结合的方法。组合方法基于评价函数从两个照度分布中选择精确插值的区域。该函数使用光源位置与计算点之间的距离，光的入射角以及等同线之间的对应关系。在交互反射环境下的动画渲染中证明了该方法的有效性。

This project has developed a fast method for generating photorealistic animations taking into account interreflection of light when changing light source positions. The developed method calculates illuminance distributions at several sampled light source positions taking into account interreflection of light in advance, and stores the distributions as isophotic lines. After specifying a new light source position, illuminance distributions at the light source position are interpolated by warping the isophotic lines. The novel approach can be interpolated illminance distributions that are nonlinear in regard to light source position, because the method uses a morphing technique to the position and shape of isophotic lines.To improve the accuracy of the proposed illumination morphing method, the resultant images are compared with a traditional linear interpolation method, and a combination method of the illumination morphing and linear interpolation methods is developed. The combination method selects accurately interpolated areas from two illuminance distributions based on an evaluation function. The function uses distance between a light source position and a calculation point, an incident angle of light, and correspondence between isophotic lines. The usefulness of the proposed method is demonstrated in rendering an animation under interreflective environment.