Computational Statistics and Data Visualization

This book is the third volume of the Handbook of Computational Statistics and covers the field of Data Visualization. In line with the companion volumes, it contains a collection of chapters by experts in the field to present readers with an up-to-date and comprehensive overview of the state of the art. Data Visualization is an active area of application and research and this is a good time to gather together a summary of current knowledge. Graphic displays are often very effective at communicating information. They are also very often not effective at communicating information. Two important reasons for this state of affairs are that graphics can be produced with a few clicks of the mouse without any thought, and that the design of graphics is not taken seriously in many scientific textbooks. Some people seem to think that preparing good graphics is just a matter of common sense (in which case their common sense cannot be in good shape) and others believe that preparing graphics is a low-level task, not appropriate for scientific attention. This volume of the Handbook of Computational Statistics takes graphics for Data Visualization seriously.Data Visualization, Exploratory Graphics.

Dynamic 3D Network Data Visualization

Monitoring network traffic has always been an arduous and tedious task because of the complexity and sheer volume of network data that is being consistently generated. In addition, network growth and new technologies are rapidly increasing these levels of complexity and volume. An effective technique in understanding and managing a large dataset, such as network traffic, is data visualization. There are several tools that attempt to turn network traffic into visual stimuli. Many of these do so in 2D space and those that are 3D lack the ability to display network patterns effectively. Existing 3D network visualization tools lack user interaction, dynamic generation, and intuitiveness. This project proposes a user-friendly 3D network visualization application that creates both dynamic and interactive visuals. This application was built using the Bablyon.js graphics framework and uses anonymized data collected from a campus network

Volume ray casting techniques and applications using general purpose computations on graphics processing units

Traditional 3D computer graphics focus on rendering the exterior of objects. Volume rendering is a technique used to visualize information corresponding to the interior of an object, commonly used in medical imaging and other fields. Visualization of such data may be accomplished by ray casting; an embarrassingly parallel algorithm also commonly used in ray tracing. There has been growing interest in performing general purpose computations on graphics processing units (GPGPU), which are capable exploiting parallel applications and yielding far greater performance than sequential implementations on CPUs. Modern GPUs allow for rapid acceleration of volume rendering applications, offering affordable high performance visualization systems. This thesis explores volume ray casting performance and visual quality enhancements using the NVIDIA CUDA platform, and demonstrates how high quality volume renderings can be produced with interactive and real time frame rates on modern commodity graphics hardware. A number of techniques are employed in this effort, including early ray termination, super sampling and texture filtering. In a performance comparison of a sequential versus CUDA implementation on high-end hardware, the latter is capable of rendering 60 frames per second with an impressive price-performance ratio heavily favoring GPUs. A number of unique volume rendering applications are explored including multiple volume rendering capable of arbitrary placement and rigid volume registration, hypertexturing and stereoscopic anaglyphs, each greatly enhanced by the real time interaction of volume data. The techniques and applications discussed in this thesis may prove to be invaluable tools in fields such as medical and molecular imaging, flow and scientific visualization, engineering drawing and many others

The volume in focus: hardwareassisted focus and context effects for volume visualization

In many volume visualization applications there is some region of specific interest where we wish to see fine detail - yet we do not want to lose an impression of the overall picture. In this research we apply the notion of focus and context to texture-based volume rendering. A framework has been developed that enables users to achieve fast volumetric distortion and other effects of practical use. The framework has been implemented through direct programming of the graphics processor and integrated into a volume rendering system. Our driving application is the effective visualization of aneurysms, an important issue in neurosurgery. We have developed and evaluated an easy-to-use system that allows a neurosurgicalteam to explore the nature of cerebral aneurysms, visualizing the aneurysm itself in fine detail while still retaining a view of the surrounding vasculature

Surface Shape Perception in Volumetric Stereo Displays

In complex volume visualization applications, understanding the displayed objects and their spatial relationships is challenging for several reasons. One of the most important obstacles is that these objects can be translucent and can overlap spatially, making it difficult to understand their spatial structures. However, in many applications, for example medical visualization, it is crucial to have an accurate understanding of the spatial relationships among objects. The addition of visual cues has the potential to help human perception in these visualization tasks. Descriptive line elements, in particular, have been found to be effective in conveying shape information in surface-based graphics as they sparsely cover a geometrical surface, consistently following the geometry. We present two approaches to apply such line elements to a volume rendering process and to verify their effectiveness in volume-based graphics. This thesis reviews our progress to date in this area and discusses its effects and limitations. Specifically, it examines the volume renderer implementation that formed the foundation of this research, the design of the pilot study conducted to investigate the effectiveness of this technique, the results obtained. It further discusses improvements designed to address the issues revealed by the statistical analysis. The improved approach is able to handle visualization targets with general shapes, thus making it more appropriate to real visualization applications involving complex objects

Obscurance-based Volume Rendering Framework

IEEE/ EG Symposium on Volume and Point-Based Graphics (2008) H.- C. Hege, D. Laidlaw, R. Pajarola, O. Staadt (Editors)lighting effects in a faster way than global illumination. Its application in volume visualization is of special interest since it permits us to generate a high quality rendering at a low cost. In this paper, we propose an obscurancebased framework that allows us to obtain realistic and illustrative volume visualizations in an interactive manner. Obscurances can include color bleeding effects without additional cost. Moreover, we obtain a saliency map from the gradient of obscurances and we show its application to enhance volume visualization and to select the most salient views.publishedVersio

Real-time volume rendering and tractography visualization on the web

In the field of computer graphics, Volume Rendering techniques allow the visualization of 3D datasets, and specifically, Volume Ray-Casting renders images from volumetric datasets, typically used in some scientific areas, such as medical imaging -- This article aims to describe the development of a combined visualization of tractography and volume rendering of brain T1 MRI images in an integrated way -- An innovative web viewer for interactive visualization of neuro-imaging data has been developed based on WebGL -- This recently developed standard enables the clients to use the web viewer on a wide range of devices, with the only requirement of a compliant web-browser -- As the majority of the rendering tasks take place in the client machine, the effect of bottlenecks and server overloading are minimized -- The web application presented is able to compete with desktop tools, even supporting high graphical demands and facing challenges regarding performance and scalability -- The developed software modules are available as open source code and include MRI volume data and tractography generated by the Diffusion Toolkit, and connectivity data from the Connectome Mapping Toolkit -- Our contribution for the Volume Web Viewer implements early ray termination step according to the tractography depthmap, combining volume images and estimated white matter fibers -- Furthermore, the depthmap system extension can be used for visualization of other types of data, where geometric and volume elements are displayed simultaneousl

Internet-based Medical Data Rendering and Image Enhancement Using Webgl and Apache Server

Internet-based medical data visualization has wide applications in distributed medical collaborations and treatment. It can be achieved through volume rendering technique, which is a key method for medical image exploration and has been applied to the clinical medical fields such as disease diagnosis and image-guided interaction.In this project, we implement some medical data processing and optical mapping methods for web-based medical data visualization and image enhancement. The Web Graphics Library (WebGL) is used with JavaScript for rendering 3D graphics in a web browser. WebGL supports GPU based volume rendering which is an efficient tool for visual analysis of medical data, which involves vertex shaders and fragment shaders. The vertex shader provides space coordinates, and the fragment shader provides color.Network-based volume rendering is used to visualize data in a 3D form. An image processing method is implemented to transfer the 3D dataset into multiple slices of 2D image data and WebGL is employed to render 3D medical data in web browsers. Volume rendering is accomplished using the volume ray casting algorithm implemented with WebGL2. We collect new medical data and process them to fit the web-based rendering environment. The submitted work will explain the process of preparing and loading medical data suitable to be rendered. All the visualized data can be enhanced with the developed methods to emphasize the image feature of interest. We also add new control points for optical mapping and rendering medical data in a web browser in real-time. The software platform is running on Apache Web Server for network-based data visualization. The developed image enhancements and property control methods can improve medical data visualization on web browsers, which will be helpful for internet-based medical data analysis and exploration, as well as medical diagnosis and treatment.https://ir.library.illinoisstate.edu/ursit/1000/thumbnail.jp