Generalized Image Acquisition and Analysis

On Plenoptic Multiplexing and Reconstruction

Photography has been striving to capture an ever increasing amount of visual information in a single image. Digital sensors, however, are limited to recording a small subset of the desired information at each pixel. A common approach to overcoming the limitations of sensing hardware is the optical multiplexing of high-dimensional data into a photograph. While this is a well-studied topic for imaging with color filter arrays, we develop a mathematical framework that generalizes multiplexed imaging to all dimensions of the plenoptic function. This framework unifies a wide variety of existing approaches to analyze and reconstruct multiplexed data in either the spatial or the frequency domain. We demonstrate many practical applications of our framework including high-quality light field reconstruction, the first comparative noise analysis of light field attenuation masks, and an analysis of aliasing in multiplexing applications.


Interactive Volume Caustics in Single-Scattering Media

Zhao Dong, Wei Hu, Ivo Ihrke, Thorsten Grosch, Hans-Peter Seidel
In: Proceedings of I3D 2010.


Volume caustics are intricate illumination patterns formed by light first interacting with a specular surface and subsequently being scattered inside a participating medium. Although this phenomenon can be simulated by existing techniques, image synthesis is usually non-trivial and time-consuming. Motivated by interactive applications, we propose a novel volume caustics rendering method for single-scattering participating media. Our method is based on the observation that line rendering of illumination rays into the screen buffer establishes a direct light path between the viewer and the light source. This connection is introduced via a single scattering event for every pixel affected by the line primitive. Since the GPU is a parallel processor, the radiance contributions of these light paths to each of the pixels can be computed and accumulated independently. The implementation of our method is straightforward and we show that it can be seamlessly integrated with existing methods for rendering participating media. We achieve high-quality results at real-time frame rates for large and dynamic scenes containing homogeneous participating media. For inhomogeneous media, our method achieves interactive performance that is close to real-time. Our method is based on a simplified physical model and can thus be used for generating physically plausible previews of expensive lighting simulations quickly.
Project Page Video


author = {Hu, Wei and Dong, Zhao and Ihrke, Ivo and Grosch, Thorsten and Yuan, Guodong and Seidel, Hans-Peter},
title = {Interactive Volume Caustics in Single-Scattering Media},
booktitle = {I3D '10: Proceedings of the 2010 symposium on Interactive 3D graphics and games},
year = {2010},
pages = {109--117},
publisher = {ACM},
Go to project list