Ken Brodlie - Research Page
gViz project - in collaboration
with the Universities of Oxford and Oxford Brookes, CCLRC/RAL, and
three industrial companies: NAG, IBM UK and Streamline - was carried
out under the UK e-science core programme in the period 2002-04.
It studied visualization middleware
for e-science - focusing on how to evolve visualization systems
to Grid computing. Specifically it extended IRIS Explorer to work in a secure,
distributed fashion, with the modules in the visualization pipeline
executing on remote Grid resources. It is expected that this
software will be available in the next release of IRIS Explorer from
NAG Ltd. The project also studied computational steering in Grid
environments, developing a library, the gViz library, that allows a
simulation running remotely on the Grid to be monitored and controlled
from the desktop. An important contribution of gViz, due largely
to Oxford Brookes, was the development of skML, an XML language to describe
the syntax of dataflow visualization. The gViz project has built
on our earlier work on collaborative visualization - specifically, the
EPSRC COVISA project which
showed how dataflow visualization systems can be extended to multi-user
working, by allowing individual dataflow pipelines to interconnect in
order to share data and parameters. This is now an integral
feature within IRIS Explorer.
project - in collaboration with the universities of Manchester,
Bangor and Swansea - studied advanced
environments for enabling visual supercomputing. Our
contribution, led by Jason Wood, focused on building user interfaces
for computational steering and on extending skML from gviz, to provide
semantics as well as syntax for visualization pipelines.
Integrative Biology paper presented at UK e-Science All Hands Meeting 2005
|The Integrative Biology project - a
collaboration led by University of Oxford and involving a number of
other UK universities - is exploring how e-science technologies can
help biologists in the study of heart disease and cancer tumour
growth. Our contribution, led by James Handley and Chris Goodyer,
was been in
collaboration with Richard Clayton of Sheffield University and Arun
Holden of Leeds University, in the context of heart modelling. We
have studied the potential for user interaction in models for cardiac
virtual tissue, and novel techniques for displaying multivariate,
Accuracy in Isosurfacing
Adriano Lopes and I have studied the behaviour of the trilinear interpolant used in the marching cubes algorithm to determine the surface within a cell. Our paper in IEEE TVCG gives a complete analysis of the interpolant, and develops a unique topologically correct polygonal representation for the isosurface. This representation is robust in the sense that it changes continuously as the data changes or the isovalue changes. This means that there are no visual discontinuities when the threshold lies in a neighbourhood of the saddle point value of the trilinear interpolant.
While on sabbatical in New Zealand and California, I extended previous work by my research student, Rafiq Asim, on visualization of data subject to constraints such as positivity. With Keith Unsworth of Lincoln University in New Zealand, we developed a constrined version of the Shepard family of interpolants. This enables us to visualize for example rainfall data, where observations are made at scattered locations and we wish to visualize rainfall patterns over a continuous region - while making sure that the rainfall is always greater than zero.
This is an electronic version of an article published in Computer Graphics Forum. Complete citation information for the final version of the paper, as published in the print edition of Computer Graphics Forum, is available on the Blackwell Synergy online delivery service, accessible via the journal's website at http://www.blackwellpublishing.com/journal.asp?ref=0167-7055 or http://www.blackwell-synergy.com.
Multidimensional and Multivariate Visualization
Selan dos Santos and I have sought to unify the visualization of multidimensional (function of many variables) and multivariate (data tables with multiple columns) data. The Hyperscribe tool guides a user through a sequence of projections in a continuous manner. This work was presented at Eurographics-IEEE TCVG Symposium on Visualization in 2002, and later published in Computers and Graphics (Vol 28, 2004).
The multivariate visualization research is continuing in the EU-funded VOTech project which is part of the wider European Virtual Observatory (Euro-VR). Richard Holbrey is looking at the visualization of very large multivariate datsets that occur in astronomy. Our work is in collaboration with Edinburgh and Portsmouth.
Focus and Context Volume Rendering
My research student, Marcelo Cohen, is developing a novel focus and context approach to volume rendering, that can be efficiently implemented on GPUs. The work is being done in collaboration with Nick Phillips, consultant neurosurgeon at Leeds General Infirmary.