ISSN 2079-3537      

 
 
 
                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
Scientific Visualization
Issue Year: 2011
Quarter: 1
Volume: 3
Number: 1
Pages: 19 - 31
Article Name: GENERAL IMPLEMENTATION ASPECTS OF THE GPU-BASED VOLUME RENDERING ALGORITHM
Authors: N.I. Gavrilov (Russia), V.E. Turlapov (Russia)
Address: N.I. Gavrilov
gavrilov86@gmail.com
Lobachevsky state university of Nizhny Novgorod, Russia
 
V.E. Turlapov
vadim.turlapov@cs.vmk.unn.ru
Lobachevsky state university of Nizhny Novgorod, Russia
Abstract: This paper presents GPU-based algorithms and methods of the Direct Volume Rendering (DVR) we have implemented in the “InVols” visualization framework (http://ngavrilov.ru/invols). InVols provides new opportunities for scientific and medical visualization which are not available in due measure in analogues: 1) multi-volume rendering in a single space of up to 3 volumetric datasets determined in different coordinate systems and having sizes as big as up to 512x512x512 16-bit values; 2) performing the above process in real time on a middle class GPU, e. g. nVidia GeForce GTS 250 512 MB; 3) a custom bounding mesh for more accurate selection of the desired region in addition to the clipping bounding box; 4) simultaneous usage of a number of visualization techniques including the shaded Direct Volume Rendering via the 1D- or 2D- transfer functions, multiple semi-transparent discrete iso-surfaces visualization, MIP, and MIDA. The paper discusses how the new properties affect the implementation of the DVR. In the DVR implementation we use such optimization strategies as the early ray termination and the empty space skipping. The clipping ability is also used as the empty space skipping approach to the rendering performance improvement. We use the random ray start position generation and the further frame accumulation in order to reduce the rendering artifacts. The rendering quality can be also improved by the on-the-fly tri-cubic filtering during the rendering process. InVols supports 4 different stereoscopic visualization modes. Finally we outline the visualization performance in terms of the frame rates for different visualization techniques on different graphic cards.
Language: English