Exploiting coherence in light transport simulations

Driven by the increasing demand for photorealistic computer-generated images, graphics is currently undergoing a substantial transformation to physics-based approaches which carefully process visual information characterizing both object shape and the interaction of light and matter. While the resulting methods can produce images of stunning realism, a major downside of this transition is that the underlying algorithms can degenerate into an impracticably slow brute force search when processing simple everyday inputs. My research lies at the interface of rendering algorithms, appearance modeling, and high performance computing and seeks to develop realistic methods that remain efficient over a wide range of inputs. A key approach for addressing some of these challenges entails replacing local sampling techniques with smarter coherent algorithms that share information globally. I will discuss three different situations where the concept of coherence plays a vital role. The first involves local reflectance models that are used to simulate arbitrarily layered materials. After this, I will provide a brief overview of Manifold Exploration, an algorithm that reasons about the geometric structure of light paths in high dimensional configuration spaces. Finally, I will discuss a recent work that leverages coherence to render cinematic animation sequences at a small fraction of the original cost. The talk will conclude with a discussion of current challenges and opportunities