An inverse problem approach for automatically adjusting the parameters for rendering clouds using photographs

Yoshinori Dobashi, Wataru Iwasaki, Ayumi Ono, Tsuyoshi Yamamoto, Yonghao Yue, Tomoyuki Nishita
2012 ACM Transactions on Graphics  
Figure 1 : Examples of our method. The parameters for rendering clouds are estimated from the real photograph shown in the small inset at the top left corner of each image. The synthetic cumulonimbus clouds are rendered using the estimated parameters. Abstract Clouds play an important role in creating realistic images of outdoor scenes. Many methods have therefore been proposed for displaying realistic clouds. However, the realism of the resulting images depends on many parameters used to
more » ... them and it is often difficult to adjust those parameters manually. This paper proposes a method for addressing this problem by solving an inverse rendering problem: given a non-uniform synthetic cloud density distribution, the parameters for rendering the synthetic clouds are estimated using photographs of real clouds. The objective function is defined as the difference between the color histograms of the photograph and the synthetic image. Our method searches for the optimal parameters using genetic algorithms. During the search process, we take into account the multiple scattering of light inside the clouds. The search process is accelerated by precomputing a set of intermediate images. After ten to twenty minutes of precomputation, our method estimates the optimal parameters within a minute.
doi:10.1145/2366145.2366164 fatcat:44aykuxtxvhurcpgnf3cb2yhoe