GPU-Based Monte-Carlo Volume Rendering

Christof Rezk-Salama

Background

This work presents a practical, high-quality, hardware-accelerated volume rendering approach including scattering, environment mapping, and ambient occlusion. We examine the application of stochastic raytracing techniques for volume rendering and provide a fast GPU-based prototype implementation. In addition, we propose a simple phenomenological scattering model, closely related to the Phong illumination model that many artists are familiar with. We demonstrate our technique being capable of producing convincing images, yet flexible enough for digital productions in practice.

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Image generation is performed by a GPU-based multi-pass rendering technique:

First Pass: Determine the first hit (left) with an isosurface and calculate the gradient vector (right)

Isosurface Beauty Pass: An environment map is sampled multiple times at random position to calculate Phong illumination, Preview (left) and Final Quality (right)

Isosurface Ambient Occlusion Pass: Cast several rays across the hemisphere centered about the normal vector and count the rays that hit the isosurface again. Ambient Occlusion (left) and Composite with Beauty Pass (right)

Scattering Pass: Several rays are scattered into the interiour of the object and traced until they leave the object.
Scattering Preview (left), Scattering Final (middle) and Final Composite of all Passes (right)

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Example Videos:

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All data sets (except for the Abominal CT) are available at the Data Archive of the Texas Advanced Computing Center at the University of Texas at Austin.

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More example images:

Papers

·	C. Rezk Salama
	GPU-Based Monte-Carlo Volume Raycasting
	In in Proc. Pacific Graphics, 2007
	[bib]  [pdf]

·	C. Rezk Salama
	Production-Ready GPU-based Monte-Carlo Volume Raycasting
	In Technical Report , Computer Graphics Group, Universität Siegen, 2007
	[bib]  [pdf]

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