Ken Martin

An Open Source Approach to Developing Software in a Small Organization

The software development approach that developers at Kitware use borrows techniques from agile development and extreme programming and emphasizes long-term, ongoing projects. The company has used this approach on open source and closed-source projects in a wide range of sizes

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.

A modular, extensible visualization system architecture for culled, prioritized data streaming

Massive dataset sizes can make visualization difficult or impossible. One solution to this problem is to divide a dataset into smaller pieces and then stream these pieces through memory, running algorithms on each piece. This paper presents a modular data-flow visualization system architecture for culling and prioritized data streaming. This streaming architecture improves program performance both by discarding pieces of the input dataset that are not required to complete the visualization, and by prioritizing the ones that are. The system supports a wide variety of culling and prioritization techniques, including those based on data value, spatial constraints, and occlusion tests. Prioritization ensures that pieces are processed and displayed progressively based on an estimate of their contribution to the resulting image. Using prioritized ordering, the architecture presents a progressively rendered result in a significantly shorter time than a standard visualization architecture. The design is modular, such that each module in a user-defined data-flow visualization program can cull pieces as well as contribute to the final processing order of pieces. In addition, the design is extensible, providing an interface for the addition of user-defined culling and prioritization techniques to new or existing visualization modules.

Real time tracking of borescope tip pose

The authors present a technique for the real-time tracking of borescope tip pose. While borescopes are used on a regular basis to inspect machinery for wear or damage, knowing the exact location of a borescope is difficult due to its flexibility. They present a technique for incremental borescope pose determination consisting of off-line feature extraction and on-line pose determination. The feature extraction precomputes from a CAD model of the object the features visible in a selected set of views. The on-line pose determination starts from a current pose estimate, determines the visible model features, projects them into a two-dimensional image coordinate system, matches each to the current borescope video image (without explicitly extracting features from this image), and uses the differences between the predicted and matched feature positions in a gradient descent technique to iteratively refine the pose estimate. The approach supports the mixed use of both matched feature positions and errors along the gradient within the pose determination. The on-line system is designed to execute at video frame rates, providing a continual indication of borescope tip pose.

Enhancements to VTK enabling scientific visualization in immersive environments

Modern scientific, engineering and medical computational simulations, as well as experimental and observational data sensing/measuring devices, produce enormous amounts of data. While statistical analysis provides insight into this data, scientific visualization is tactically important for scientific discovery, product design and data analysis. These benefits are impeded, however, when scientific visualization algorithms are implemented from scratch — a time-consuming and redundant process in immersive application development. This process can greatly benefit from leveraging the state-of-the-art open-source Visualization Toolkit (VTK) and its community. Over the past two (almost three) decades, integrating VTK with a virtual reality (VR) environment has only been attempted to varying degrees of success. In this paper, we demonstrate two new approaches to simplify this amalgamation of an immersive interface with visualization rendering from VTK. In addition, we cover several enhancements to VTK that provide near real-time updates and efficient interaction. Finally, we demonstrate the combination of VTK with both Vrui and OpenVR immersive environments in example applications.