Tag Archives: Visualization

RIVIC Graduate School: Visual Computing

The 2010 Wales RIVIC Visual Computing Graduate School is a four-day meeting, bringing distinguished international scientists in computer graphics, computer vision, image processing, visualization, and other areas of visual computing together to share their expertise, knowledge, wisdom, and vision with young researchers (e.g. PhD students and PostDocs). The school provides a stimulating opportunity for young researchers and Ph.D. students. The participants will benefit from direct interaction and discussions with leaders in Visual Computing. Participants will also have the possibility to present the results of their research, and to interact with their scientific peers, in a friendly and constructive environment. The Graduate School offers scientists and researchers a rare opportunity to explore the future research directions of visual computing, especially the convergence of its different areas. The event features insightful talks from keynote speakers, research presentations, discussion panels, and PhD forums. Its informal social events provide young researchers a valuable opportunity to exchange research experience and explore potentials for collaboration.

Smooth Graphs for Visual Exploration of Higher-Order State Transitions

Representing higher order paths with smooth linesIn this paper, we present a new visual way of exploring state sequences in large observational time-series. A key advantage of our method is that it can directly visualize higher-order state transitions. A standard first order state transition is a sequence of two states that are linked by a transition. A higher-order state transition is a sequence of three or more states where the sequence of participating states are linked together by consecutive first order state transitions. Our method extends the current state-graph exploration methods by employing a two dimensional graph, in which higher-order state transitions are visualized as curved lines. All transitions are bundled into thick splines, so that the thickness of an edge represents the frequency of instances. The bundling between two states takes into account the state transitions before and after the transition. This is done in such a way that it forms a continuous representation in which any subsequence of the timeseries is represented by a continuous smooth line. The edge bundles in these graphs can be explored interactively through our incremental selection algorithm. We demonstrate our method with an application in exploring labelled time-series data from a biological survey, where a clustering has assigned a single label to the data at each time-point. In these sequences, a large number of cyclic patterns occur, which in turn are linked to specific activities. We demonstrate how our method helps to find these cycles, and how the interactive selection process helps to find and investigate activities.

Jorik Blaas, Charl P. Botha, Ed Grundy, Mark W. Jones, Robert S. Laramee and Frits H. Post.
IEEE Transactions on Visualization and Computer Graphics 15(6), 969-976, 2009. [doi] [BibTeX]

Visualization of Sensor Data from Animal Movement

Accelerometry data visualized on a sphereA new area of biological research is identifying and grouping patterns of behaviour in wild animals by analysing data obtained through the attachment of tri-axial accelerometers. As these recording devices become smaller and less expensive their use has increased. Currently acceleration data are visualised as 2D time series plots, and analyses are based on summary statistics and the application of Fourier transforms. We develop alternate visualisations of this data so as to analyse, explore and present new patterns of animal behaviour. Our visualisations include interactive spherical scatterplots, spherical histograms, clustering methods, and feature-based state diagrams of the data. We study the application of these visualisation methods to accelerometry data from animal movement. The reaction of biologists to these visualisations is also reported.

Edward Grundy, Mark W. Jones, Robert S. Laramee, Rory P. Wilson and Emily L.C. Shepard
Eurovis 2009, Computer Graphics Forum 28(3), 815-822, 2009 [doi] [BibTeX]

Visualization and Computer Graphics on Isotropically Emissive Volumetric Displays


The availability of commodity volumetric displays provides ordinary users with a new means of visualizing 3D data. Many of these displays are in the class of isotropically emissive light devices, which are designed to directly illuminate voxels in a 3D frame buffer, producing x-ray-like visualizations. While this technology can offer intuitive insight into a 3D object, the visualizations are perceptually different from what a computer graphics or visualization system would render on a 2D screen. This paper formalizes rendering on isotropically emissive displays and introduces a novel technique that emulates traditional rendering effects on isotropically emissive volumetric displays, delivering results that are much closer to what is traditionally rendered on regular 2D screens. Such a technique can significantly broaden the capability and usage of isotropically emissive volumetric displays. Our method takes a 3D data set or object as the input, creates an intermediate light field, and outputs a special 3D volume data set called a lumi-volume. This lumi-volume encodes approximated rendering effects in a form suitable for display with accumulative integrals along unobtrusive rays. When a lumi-volume is fed directly into an isotropically emissive volumetric display, it creates a 3D visualization with surface shading effects that are familiar to the users. The key to this technique is an algorithm for creating a 3D lumi-volume from a 4D light field. In this paper, we discuss a number of technical issues, including transparency effects due to the dimension reduction and sampling rates for light fields and lumi-volumes. We show the effectiveness and usability of this technique with a selection of experimental results captured from an isotropically emissive volumetric display, and we demonstrate its potential capability and scalability with computer-simulated high-resolution results.

Benjamin Mora, Ross Maciejewski, Min Chen and David S. Ebert
IEEE Transactions on Visualization and Computer Graphics, March-April 2009, Vol. 15. No 2, pp. 221-234.