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.


Parallel Visual Computing

Seminar in winter term 2012/13

Lecturers: Ivo Ihrke, Tobias Ritschel, Mario Fritz

General Information

Course webpage

When: 2012, Oct. 18th to 2013, Jan. 31st
Where: E1.7 room 0.01
Registration for mailing list: send email to Ivo Ihrke (


This seminar covers the hands-on use of parallel hardware (CPUs and GPUs) for visual computing, i.e.,

  • Computer vision (e.g., from simple image operations to classification)
  • Computer graphics (e.g., advanced shading)
  • Scientific computing (e.g., equation solving)

The target audience are students in computer science or related fields. Good C++ programming skills, basic knowledge about 3D geometry, image processing, and computer graphics are required. This seminar will be based on hands-on parallel programming:

  • Every one week, a tutor will present a problem with an interesting parallel solution.
  • On the same day there will be a programming assignment on the topic.
  • Teams of two people will work on this assignment
  • Every team demos their solution and we discuss


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