Turning huge data volumes into images
The first thing that a CAT scan of the human heart produces is simply data. Together with graphics hardware, the image processing software then constructs a picture that can be displayed on the computer. Its only natural that medical personnel, and even materials researchers, desire the most detailed images possible. But this always means processing huge amounts of data. So how can the internal structure of the heart appear on a monitor as a realistic, 3D color image, particularly when the data records merely outline its structures in varying shades of gray? Through something called direct volume rendering. This mathematical process allows the 3D structure to be interactively moved and controlled by the viewer at the voxel level. Voxels, or volume elements, are the 3D equivalent of two-dimensional pixels - the picture elements. Software modules such as Multi-Raycaster or Raytracer bring different lighting effects to a picture, making it appear more realistic. Today, effects such as shadowing, reflections, variable transparency and simulated material and surface characteristics are possible, as well as cross-sections at any angle. The most advanced programs are now penetrating the fourth dimension of time. The result is that many individual images merge to make a film - as the beating heart. The leader in its class of software is a program called PV-4D. Developed by the Fraunhofer Institute for Industrial Mathematics ITWM it does not require any special graphics hardware. At present, we can visualize 150 data records, each with a resolution of 10243 voxels, explains Dr. Franz-Josef Pfreundt. This corresponds to about 150 billion voxels that must be converted into 10242 pixels for color monitor images. This is how animation effects are created in which objects can be turned, cut and flown through in any fashion - even in stereoscopic vision with special glasses. For the first time, very large volumes of data can be interactively visualized in the dimensions of space and time. PV-4D is a parallel-processing program and thus optimized for standard PC clusters. Even special graphics computer hardware cannot outperform the software. Researchers at the Institutes Competence Center for High Performance Computing and Visualization have also managed to depict complex flow processes with their software. By the end of this year, their goal is to interactively visualize data volumes of up to one terabyte (1024 gigabytes).,Contact:,Dr. Franz-Josef Pfreundt,Phone: +49 6 31 / 2 05-27 44,Fax: +49 6 31 / 2 05-41 39,E-mail: pfreundt@itwm.fraunhofer.de Dr. Carsten Lojewski,Phone: +49 6 31 / 3 03-18 08,E-mail: lojewski@itwm.fraunhofer.de Fraunhofer-Institut fur Techno- und Wirtschaftsmathematik ITWM,Gottlieb-Daimler-Strasse, ,Geb. 49,67663 Kaiserslautern, Germany,http://www.itwm.fraunhofer.de/index.php?abt=zentral&inc=index&item=index&language=en For further information:,ITWM: PV-4D,http://www.itwm.fhg.de/hpc/visualisierung/visualisierung_en.html
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