RTPara - Distributed Ray-Casting Application
for Hewlett-Packard Scalabe Visualization Array
(July, 2007)
This is a ray-casting based volume rendering application designed for
Hewlett-Packard Visualization Array. The application allows the visualization
of volume datasets in a distributed environment by rendering isosurfaces
using screen space or object space decomposition approaches.
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Introduction
Volume rendering is a technique used to display a 2D projection of a 3D discretely sampled data set (sampled representation of a 3D continuous signal). A typical 3D data set is a group of 2D slice images acquired by a CT (Computed Tomography) or MRI (Magnetic Resonance Imaging) scanner.
To render a 2D projection of the 3D data set, we need to assign an opacity value and a color value to every voxel. These are usually defined using a function that determines the RGBA (red, green, blue, alpha) values for every possible voxel value (transfer function).
A volume may be rendered by displaying surfaces of equal values (isosurface). Isosurfaces can be extracted in two fundamentally different ways, which are represented by direct and indirect methods. Direct volume rendering methods extract an isosurface by resampling the volume data along the viewing rays at evenly located sample points. Rays are cast from the view point through the center of each pixel and the first point where the ray intersects the isosurface is determined.
Rendering methods belonging to the ray-casting or ray-tracing family can easily be implemented in a distributed environment. RTPara application contains both the object space decomposition, which partitions the data to be rendered among the participating computing resources (nodes), and the screen space approach, which assigns parts of final the image to be rendered to the nodes. In both cases the resulting partial images need to be composited together to form the final image.
Documentation
| File | Description |
|---|---|
| rtpara-0.1.pdf | Manual of RTPara |
Downloads
| File | Description |
|---|---|
| rtpara-0.1-2.tar.gz | Source code of RTPara |
| File | Description |
|---|---|
| rtpara-0.1-2.x86_64.rpm | Compiled version of RTPara for AMD64 HP-XC |
Data Sets
The data sets can be downloaded from http://visdata.ik.bme.hu/. Note that only the data sets under "Data Sets for the Distributed Ray-Casting Application (RTPara)" are supported by this application.
