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Visual Computing Forum

The Visual Computing Forum, or VCF, is a series of seminars organized by the visualization group with selected talks from the fields of visualization, image processing, computer graphics, and so on. The individual seminars are arranged approximately once a month, on Fridays from 11am to 12am, and they will be interleaved with the MedViz seminars. They will be held either at the Høyteknologisenteret or at the VilVite Science Center

If you wish to be informed about upcomming VCF events, please write an e-mail to "", "" or "".   Seminars calendar   

     December 12, 2014

Place: MedViz Facilities., Møllendalsbakken 7, 5th floor

Time: Friday December 12, 2014, from 12.00 to 13.30

Talk 1: Fast volumetric super-resolution reconstruction of organs from moving subjects

Speaker: Bernhard Kainz

Abstract: Magnetic Resonance Imaging (MRI) is a primary tool for clinical investigation of the brain and fetal organs. High resolution imaging with volumetric coverage using stacks of slices or true three dimensional (3D) methods is widely available and provides rich data for image analysis. However such detailed volumetric data generally takes everal minutes to acquire and requires the subject to remain still or move only small distances during acquisition. Fetal organ imaging introduces a number of additional challenges. Maternal breathing may move the fetus and the fetus itself can and does spontaneously move during imaging. These movements are unpredictable and may be large, particularly involving substantial head and body rotations. Motion correction methods have revolutionized MRI of the fetus by reconstructing a high-resolution 3D volume of fetal organs from such motion corrupted stacks of 2D slices. Such reconstructions are valuable for both clinical and research applications. However, reconstruction is computationally expensive and can only be performed off line. Information about the accuracy of the scan and potential uncertainties is unknown or not considered in the clinical practice. In this talk I will discuss the fundamentals of fetal MRI reconstruction and it's parallelization and hardware acceleration for a future on-line application during the scan. Furthermore, I am looking forward to a discussion about potential application of novel visualization techniques to communicate varying uncertainties of the reconstruction to examining radiologists and scientists.

Talk 2: New perfusion analysis algorithms for MR and ultrasound

Speakers: Torfinn Taxt and Radovan Jirik

Good estimates of the microvascular functional (perfusion) parameters in normal and pathological tissues is based on a) good estimates of the local arterial input functions (aifs), b) adequate tissue residual function models (trfs) and c) tissue contrast signals with reasonable signal to noise ratios. This talk will present some recent developments to obtain reliable aif estimates in MR and ultrasound using blind deconvolution methods. A presentation of pharmacokinetic trf models for leaky capillaries will also be given.

Talk 3: Deriving Anatomical Context from 4D Ultrasound

Speaker: Ivan Viola

Real-time three-dimensional (also known as 4D) ultrasound imaging using matrix array probes has the potential to create large-volume information of entire organs such as the liver without external tracking hardware. This information can in turn be placed into the context of a CT or MRI scan of the same patient. However for such an approach many image processing challenges need to be overcome and sources of error addressed, including reconstruction drift, anatomical deformations, varying appearance of anatomy, and imaging artifacts. In this work, we present a fully automatic system including robust image-based ultrasound tracking, a novel learning-based global initialization of the anatomical context, and joint mono- and multi-modal registration. In an evaluation on 4D US sequences and MRI scans of eight volunteers we achieve automatic reconstruction and registration without any user interaction, assess the registration errors based on physician-defined landmarks, and demonstrate realtime tracking of free-breathing sequences.

Additional material: Flyer

     November 28, 2014

Video Visualization: An Overview

Speaker: Andrea Brambilla (Visualization Group, University of Bergen)

Place: Room 3137, floor 3, HIB (data blokk), Thormøhlensgate 55

Time: Friday November 28, 2014, from 10.15am to 11.15am

Videos are one of the most widespread media for collecting, communicating and archiving information. Nowadays, acquiring videos is a relatively straightforward process, and this explains their success in the context of entertainment, surveillance, sport events, and so on. On the other hand, watching and extracting information from a video stream is a lengthy process. Automatic techniques are only partially sucessful because of the intrinsic complexity of this kind of data. Video visualization is a growing research field which aims at easying the study of video data. It relies on both automatic techniques and user interaction, exploiting the best of both worlds. In this talk, I will introduce this field, focusing on its evolution from computer vision. I will discuss the main challenges and present an overview of the state-of-the-art. The talk will conclude with a discussion of the open problems and the expected future developments...

Additional material: Flyer, Slides

     October 31, 2014

Interactive Visual Steering Analysis of Complex Engineering-Simulation Ensembles

Speaker: Kresimir Matkovic (VRVis Research Center, Vienna, Austria)

Place: Room 3137, floor 3, HIB (data blokk), Thormøhlensgate 55

Time: Friday October 31, 2014, from 10.00am to 11.00am

In this talk we propose a novel approach to interactive visual steering of simulation ensembles. A simulation ensemble is a collection of simulation runs of the same simulation model using different sets of control parameters. Due to increasing pressure on car manufacturers, for example, to meet new emission regulations, to improve efficiency, and to reduce noise, both simulation and visualization are pushed to their limits. We describe a successful realization of a tightly coupled steering loop, integrating new simulation technology and interactive visual analysis in a prototyping environment for automotive industry system design. By coupling interactive visualization with the simulation back-end - computational steering, it is now possible to quickly prototype a new system, starting from a non-optimized initial prototype and the corresponding simulation model. We introduce two kinds of simulation steering: a model refinement approach, and a hybrid visual steering. The ability to early see the first results from a multidimensional simulation space - thousands of simulations are run for a multidimensional variety of input parameters - and to quickly go back into the simulation and request more runs in particular parameter regions of interest significantly improves the prototyping process and provides a deeper understanding of the system behavior. The hybrid steering adds an automatic optimization in order to support a region of interest selection in the high-dimensional parameter space. The excellent results and a very positive feedback from domain experts which we achieved for the common rail injection system strongly suggest that our approach has a great potential of being generalized to other, similar scenarios.

After the seminar, Geir Smestad (master student in visualization at UiB) will defend his master thesis, entitled Interactive Visual Analysis of Streaming Data.

Additional material: Flyer

     September 19, 2014

Place: Store Auditorium, floor 2, HIB (data blokk), Thormøhlensgate 55

Time: Friday September 19, 2014, from 14.00 on

Talk 1: Collaboration in Multi-User Virtual Reality

Speaker: Prof. Dr. Bernd Fröhlich (Bauhaus-Universität in Weimar, Germany)

Immersive telepresence allows distributed groups of users to meet in a shared virtual 3D world. Our approach uses two coupled projection-based multi-user setups, each providing multiple users with perspectively correct stereoscopic images. At each site, the users and their local interaction space are continuously captured using a cluster of registered depth and color cameras. The captured 3D information is transferred to the respective other location, where the remote participants are virtually reconstructed in life-size. Local and remote users can jointly or independently explore virtual environments and virtually meet face-to-face for discussions. We structure collaborative activities of collocated and remote users using Photoportals. Virtual photos and videos serve as threedimensional references to objects, places, moments in time and activities of users. They can be shared among users and serve as portals to the captured information. Our Photoportals also provide access to intermediate or alternative versions of a scenario and allow the review of recorded task sequences that include life-size representations of captured users.

Talk 2: Parallel Computing Towards Exascale

Speaker: Dr. André Brodtkorb (SINTEF, Oslo)

Today's computers are increasingly parallel, and mapping algorithms to these architectures has become increasingly difficult. Failing to adapt to the architecture leaves our performance in the dark ages, with little hope of scaling on today's and tomorrows hardware. This tutorial-like talk discusses the underlying parallel hardware constraints, different approaches to parallelism, a hands-on example for computing PI, and the use of domain specific languages to hide complexity.

Additional material: Flyer, Prof. Fröhlich's webpage, Dr. Brodtkorb's slides

     August 29, 2014

Visualization of Functional Medical Data

Speaker: Mattia Natali (Visualization Group, University of Bergen)

Place: Room 3137, floor 3, HIB (data blokk), Thormøhlensgate 55

Time: Friday August 29, 2014, from 10.15am to 11.15am

Medicine is more and more supported by technology, for instance in clinical analysis and medical intervention. Medical imaging, that non-invasively reveals internal anatomy and physiology of a body, plays an important role since radiography was introduced. In the last thirty years, structural modalities have been placed side by side new image modalities that detect physiological activities within a certain tissue or organ, providing what is known as functional medical data.
Nowadays, a large amount of data is obtained with different modalities. To offer a deeper insight into this data, visualization can be helpful. In this talk, an overview on different medical image modalities is presented, as well as corresponding techniques to turn the data into visual information that a physician can interpret for diagnosis. We will go through well known modalities such as computed tomography (CT) and magnetic resonance imaging (MRI), but also more specific medical image technologies for functional imaging, where the activation of body regions is measured during metabolic or cognitive processes. Finally, multi-modality visualization is investigated to provide functional medical data within its anatomical context. Therefore we will see an improvement in tissue characterization due to simultaneous imaging of morphological and functional information, such as the integration of MRI and Positron Emission Tomography (PET) into one single hybrid system.

Additional material: Flyer

     May 26, 2014

searchCrystal and Set Visualization

Speaker: Prof. Anselm Spoerri (School of Communication and Information, Rutgers University)

Place: Room 3137, floor 3, HIB (data blokk), Thormøhlensgate 55

Time: Monday May 26, 2014, from 14.15am to 15.15am

This talk will address how set data can be visualized using searchCrystal, which is a toolset of coordinated visualizations that can be used to compare, remix and share set data. It will be shown how searchCrystal has been used to visualize meta search data and what is popular or controversial in Wikipedia.

Additional material: Flyer, Anselm Spoerri's webpage

     April 04, 2014

Molecular dynamics simulations for biomolecules: principles and examples

Speaker: Prof. Nathalie Reuter (Dept. of Molecular Biology, UiB)

Place: Room 3137, floor 3, HIB (data blokk), Thormøhlensgate 55

Time: Friday April 04, 2014, from 10.15am to 11.15am

Molecular Dynamics (MD) simulations are widely used to model biomolecules in conditions that mimic the ones of in vitro experiments. The raw result of a MD simulation is a trajectory file containing the position of each atom in the molecule at every time step of the simulation, similar to a movie representing how the biomolecule is wiggling and giggling along simulation time. MD simulations are sometimes referred to as a 'computational microscope' because they allow the investigation of biomolecules dynamics at the atomic level of detail, something that is virtually impossible with the experimental methods currently available.
I will introduce the basic assumptions and principles behind MD simulations for biomolecules; molecular mechanics force fields, equations of motion and their integration, treatment of long-range interactions, etc... Further I will present the practicalities of running MD simulations and the different steps from system setup to trajectory post-processing.

Additional material: Flyer, Reuter Group's webpage

     March 07, 2014

State-of-the-art ultrasound blood flow imaging

Speaker: Lasse Løvstakken (Dept. Circulation and Medical imaging, NTNU)

Place: Room 3137, floor 3, HIB (data blokk), Thormøhlensgate 55

Time: Friday March 07, 2014, from 10.15am to 11.15am

The introduction of real-time ultrasound color-Doppler imaging in the mid-eighties was a major breakthrough for bedside diagnosis of cardiovascular disease. Currently this technique allows for real-time 2D and 3D imaging of blood flow, both for detection of blood and for the quantification of the blood velocity. The use of color-Doppler imaging in clinical practice is, however, mostly qualitative, used to localize but not quantify abnormal flow patterns. The reason is mostly related to the current limitations of color-Doppler related to low frame rates, beam-to-flow angle-dependencies, and a limited measurable velocity span. Further, the fundamental information and color visualization has not changed substantially since its introduction 30 years ago. Currently a technological leap is on the verge in medical ultrasound imaging. The possibility of real-time transfer and processing of channel data and software image formation allows for significantly improved image quality and frame rates in general, as well as a higher accuracy in blood flow imaging. This includes improved possibilities for imaging low flow in small vessels, and the estimation of the blood velocity vector as shown in the image above showing circular flow patterns in the left ventricle of a neonate. I will in this lecture introduce the current color-Doppler imaging modality and its limitations, and present on-going research projects on the future state of the art in ultrasound blood flow imaging.

Additional material: Flyer, Lasse Løvstakken webpage

     February 07, 2014

Applied Visualization and modeling of environment and geology

Speakers: Veronika Šoltészová (CMR Computing / UiB) and Saman Tavakoli (CMR Computing)

Place: Room 3137, floor 3, HIB (data blokk), Thormøhlensgate 55

Time: Friday February 07, 2014, from 10.15am to 11.15am

Computing is a research department of Christian Michelsen Researc (CMR) for applied research in visualization, data analysis and decision support. CMR computing works closely together with industry and government and develops innovative solutions and software prototypes in application areas such as energy, oil&gas, maritime, marine and medicine. In this talk, we will present selected projects that are related to modeling and visualization for geology and environment.
* Decision support for offshore wind turbine installation (DECOFF) Offshore operations such as the installation, maintenance and repairs of wind turbines are complex and to a large extent weather sensitive. The cost of such operations is to a high degree determined by waiting for convenient time for weather-sensitive phases (transportation of equipment, mooring, crane operations, etc.). In this project, we are developping a decision support tool which is based on real physical limitations of the equipment being used and which takes into account uncertainties such as weather conditions.
* Virtual CO2 Laboratory (VIRCOLA) The rapidly advancing deployment of geological CO2 storage requires a better comprehension of the CO2 storage reservoirs, CO2 injection, and long-term fate of geologically stored CO2. In this cross-disciplinary project, we address the challenge by building a virtual CO2 laboratory for co-visualizing and visual analysis of different data types involved.
* Geoillustrator This project focuses on illustrative geology. We will present a prototype that allows for intuitive and quick creation of geological models via sketching. The prototype supports modeling of layers, faulting.

Additional material: Flyer, Slides, CMR Computing Website

VCF seminars in 2017, 2016, 2015, 2014, 2013, 2012, 2011

 Last change: Helwig Hauser, 2009-09-22