Interactive Dynamic Volume Illumination with Refraction and Caustics

Abstract

1 AcknowledgmentsI would like to thank Professor Stefan Bruckner for supervising this thesis and for the great discussions we frequently had giving rise to the solutions presented in this thesis. I would also like to thank Itai Kallos for informative discussions giving insight in the physics behind our light model. In recent years, significant progress has been made in developing high-quality interactive methods for realistic volume illumination. However, refractiondespite being an important aspect of light propagation in participating media -has so far only received little attention. In this thesis, we present a novel approach for refractive volume illumination including caustics capable of interactive frame rates. By interleaving light and viewing ray propagation, our technique avoids memory-intensive storage of illumination information and does not require any precomputation. Propagation of refracted illumination is realized by employing a Semi-Lagrangian backward integration scheme, inspired by texture advection from the field of texture-based flow visualization. It is fully dynamic and all parameters such as light position and transfer function can be modified interactively without a performance penalty.

Deep Volumetric Ambient Occlusion

“…An entirely different approach has been followed upon by Wald et al, as they present efficient CPU data structures to realize interactive ray tracing, which they also demonstrate by realizing ambient occlusion effects [47]. More recently, Magnus et al have realized the integration of refraction and caustics into an interactive DVR pipeline, leading to realistic results [29].…”

Real-Time Denoising of Volumetric Path Tracing for Direct Volume Rendering

“…R ECENT studies evidenced perceptual benefits of applying more advanced illumination models for 3-D scientific visualizations [9], [12], [38]. Consequently, in the past years, interactive volume rendering techniques started supporting more advanced illumination effects [16], [41]. Direct Volume Rendering (DVR) using Volumetric Path Tracing (VPT) represents a new trend of volume rendering algorithms that use more advanced physicallybased lighting models to produce photo-realistic scientific visualizations [8], [10], [49], [51].…”

Void Space Surfaces to Convey Depth in Vessel Visualizations

“…Due to its relevance, researchers focused their attention on improving the perceptual capabilities of these visualizations [26]. Realistic lighting simulations [21], illustrative techniques [5] or different color schemes [3] are just some of the approaches that have been proposed in order to improve shape or depth perception.…”