Generalized Image Acquisition and Analysis

Interactive Volume Caustics in Single-Scattering Media

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.

Projects

A Reconfigurable Camera Add-On for High Dynamic Range, Multispectral, Polarization, and Light-Field Imaging

Alkhazur Manakov, Oliver Klehm, Elmar Eisemann, Hans-Peter Seidel, Ivo Ihrke
SIGGRAPH 2013



Abstract

We propose a non-permanent add-on that enables plenoptic imaging with standard cameras which we refer to as KaleidoCamera. Our design is based on a physical copying mechanism that multiplies a sensor image into a number of identical copies that still carry the plenoptic information of interest. Via different optical filters, we can then recover the desired information. A minor modification of the design also allows for aperture subsampling and, hence, light-field imaging. As the filters in our design are exchangeable, a reconfiguration for different imaging purposes is possible. We show in a prototype setup that high dynamic range, multispectral, polarization, and light-field imaging can be achieved with our design.
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Bibtex

@article{Manakov:13,
author = {Alkhazur Manakov and John Restrepo and Oliver Klehm and Ramon Hegeds and Elmar Eisemann and Hans-Peter Seidel and Ivo Ihrke},
title = {A Reconfigurable Camera Add-On for High Dynamic Range, Multispectral, Polarization, and Light-Field Imaging},
journal = {ACM Trans. on Graphics (SIGGRAPH'13)},
volume = 32, number = 4, year = 2013,
pages = {xx--yy},
}
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