Cross-Platform Ubiquitous Volume Rendering Using Programmable Shaders in VTK for Scientific and Medical Visualization.

The visualization toolkit (VTK) is a popular cross-platform, open source toolkit for scientific and medical data visualization, processing, and analysis. It supports a wide variety of data formats, algorithms, and rendering techniques for both polygonal and volumetric data. In particular, VTK's volume rendering module has long provided a comprehensive set of features such as plane clipping, color and opacity transfer functions, lighting, and other controls needed for visualization. However, due to VTK's legacy OpenGL backend and its reliance on a deprecated API, the system did not take advantage of the latest improvements in graphics hardware or the flexibility of a programmable pipeline. Additionally, this dependence on an antiquated pipeline posed restrictions when running on emerging computing platforms, thereby limiting its overall applicability. In response to these shortcomings, the VTK community developed a new and improved volume rendering module, which not only provides a modern graphics processing unit-based implementation, but also augments its capabilities with new features such as fast volume clipping, gradient-magnitude-based opacity modulation, render to texture, and hardware-based volume picking.

Integrating segmentation methods from the Insight Toolkit into a visualization application.

The Insight Toolkit (ITK) initiative from the National Library of Medicine has provided a suite of state-of-the-art segmentation and registration algorithms ideally suited to volume visualization and analysis. A volume visualization application that effectively utilizes these algorithms provides many benefits: it allows access to ITK functionality for non-programmers, it creates a vehicle for sharing and comparing segmentation techniques, and it serves as a visual debugger for algorithm developers. This paper describes the integration of image processing functionalities provided by the ITK into VolView, a visualization application for high performance volume rendering. A free version of this visualization application is publicly available and is available in the online version of this paper. The process for developing ITK plugins for VolView according to the publicly available API is described in detail, and an application of ITK VolView plugins to the segmentation of Abdominal Aortic Aneurysms (AAAs) is presented. The source code of the ITK plugins is also publicly available and it is included in the online version.