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1.	Eklund, Anders, et al. (författare) A Brain Computer Interface for Communication Using Real-Time fMRI 2010 Ingår i: Proceedings of the 20th International Conference on Pattern Recognition. - Los Alamitos, CA, USA : IEEE Computer Society. - 9781424475421 ; , s. 3665-3669 Konferensbidrag (refereegranskat)abstract We present the first step towards a brain computer interface (BCI) for communication using real-time functional magnetic resonance imaging (fMRI). The subject in the MR scanner sees a virtual keyboard and steers a cursor to select different letters that can be combined to create words. The cursor is moved to the left by activating the left hand, to the right by activating the right hand, down by activating the left toes and up by activating the right toes. To select a letter, the subject simply rests for a number of seconds. We can thus communicate with the subject in the scanner by for example showing questions that the subject can answer. Similar BCI for communication have been made with electroencephalography (EEG). The subject then focuses on a letter while different rows and columns of the virtual keyboard are flashing and the system tries to detect if the correct letter is flashing or not. In our setup we instead classify the brain activity. Our system is neither limited to a communication interface, but can be used for any interface where five degrees of freedom is necessary.
2.	Eklund, Anders, et al. (författare) Balancing an Inverted Pendulum by Thinking A Real-Time fMRI Approach 2009 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract We present a method for controlling a dynamical system using real-time fMRI. The objective for the subject in the MR scanner is to balance an inverse pendulum by activating the left or right hand or resting. The brain activity is classified each second by a neural network and the classification is sent to a pendulum simulator to change the force applied to the pendulum. The state of the inverse pendulum is shown to the subject in a pair of VR goggles. The subject was able to balance the inverse pendulum both with real activity and imagined activity. The developments here have a potential to aid people with communication disabilities e.g., locked in people. It might also be a tool for stroke patients to be ableto train the damaged brain area and get real-time feedback of when they do it right.
3.	Eklund, Anders, et al. (författare) Using Real-Time fMRI to Control a Dynamical System 2009 Ingår i: ISMRM 17th Scientific Meeting & Exhibition. - Linköping : Linköping University Electronic Press. Konferensbidrag (refereegranskat)abstract We present e method for controlling a dynamical system using real-time fMRI. The objective for the subject in the MR scanner is to balance an inverse pendulum by activating the left or right hand or resting. The brain activity is clasified each second by a neural network and the classification is sent to a pendulum simulator to change the state of the pendulum. The state of the inverse pendulum is shown to the subject in a pair of VR goggles. The subject was able to balance the inverse pendulum during a 7 minute test run.
4.	Eklund, Anders, et al. (författare) Using Real-Time fMRI to Control a Dynamical System by Brain Activity Classification 2010 Rapport (övrigt vetenskapligt/konstnärligt)abstract We present a method for controlling a dynamical system using real-time fMRI. The objective for the subject in the MR scanner is to balance an inverted pendulum by activating the left or right hand or resting. The brain activity is classified each second by a neural network and the classification is sent to a pendulum simulator to change the force applied to the pendulum. The state of the inverted pendulum is shown to the subject in a pair of VR goggles. The subject was able to balance the inverted pendulum during several minutes, both with real activity and imagined activity. In each classification 9000 brain voxels were used and the response time for the system to detect a change of activity was on average 2-4 seconds. The developments here have a potential to aid people with communication disabilities, such as locked in people. Another future potential application can be to serve as a tool for stroke and Parkinson patients to be able to train the damaged brain area and get real-time feedback for more efficient training.
5.	Eklund, Anders, 1981-, et al. (författare) Using Real-Time fMRI to Control a Dynamical System by Brain Activity Classification 2009. - 1 Ingår i: Medical Image Computing and Computer-Assisted Intervention – MICCAI 2009. - Berlin, Heidelberg : Springer Berlin/Heidelberg. - 9783642042676 - 9783642042683 ; , s. 1000-1008 Konferensbidrag (refereegranskat)abstract We present a method for controlling a dynamical system using real-time fMRI. The objective for the subject in the MR scanner is to balance an inverted pendulum by activating the left or right hand or resting. The brain activity is classified each second by a neural network and the classification is sent to a pendulum simulator to change the force applied to the pendulum. The state of the inverted pendulum is shown to the subject in a pair of VR goggles. The subject was able to balance the inverted pendulum during several minutes, both with real activity and imagined activity. In each classification 9000 brain voxels were used and the response time for the system to detect a change of activity was on average 2-4 seconds. The developments here have a potential to aid people with communication disabilities, such as locked in people. Another future potential application can be to serve as a tool for stroke and Parkinson patients to be able to train the damaged brain area and get real-time feedback for more efficient training.
6.	Gunnarsson, Ann-Sofie, et al. (författare) Visualization of Sensor Data Using Mobile Phone Augmented Reality 2006 Ingår i: ISMAR 2006,2006. - Los Alamitos, CA, USA : IEEE Computer Society. ; , s. 233- Konferensbidrag (refereegranskat)
7.	Gyllensvärd, Frida, 1980- (författare) Efficient Methods for Volumetric Illumination 2011 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Modern imaging modalities can generate three-dimensional datasets with a very high detail level. To transfer all the information to the user in an efficient way there is a need for three-dimensional visualization. In order to enhance the diagnostic capabilities the utilized methods must supply the user with fast renderings that are easy to interpret correctly.It can thus be a challenge to visualize a three-dimensional dataset in a way that allows the user to perceive depth and shapes. A number of stereoscopic solutions are available on the market but it is in many situations more practical and less expensive to use ordinary two-dimensional displays. Incorporation of advanced illumination can, however, improve the perception of depth in a rendering of a volume. Cast shadows provide the user with clues of distances and object hierarchy. Simulating realistic light conditions is, however, complex and it can be difficult to reach interactive frame rates. Approximations and clever implementations are consequently required.This thesis presents efficient methods for calculation of illumination with the objective of providing the user with high spatial and shape perception. Two main types of light conditions, a single point light source and omni-directional illumination, are considered. Global transport of light is efficiently estimated using local piecewise integration which allows a graceful speed up compared to brute force techniques. Ambient light conditions are calculated by integrating the incident light along rays within a local neighborhood around each point in the volume.Furthermore, an approach that allows the user to highlight different tissues, using luminous materials, is also available in this thesis. A multiresolution data structure is employed in all the presented methods in order to support evaluation of illumination for large scale data at interactive frame rates.
8.	Henrysson, Anders, 1976- (författare) Bringing Augmented Reality to Mobile Phones 2007 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract With its mixing of real and virtual, Augmented Reality (AR) is a technology that has attracted lots of attention from the science community and is seen as a perfect way to visualize context-related information. Computer generated graphics is presented to the user overlaid and registered with the real world and hence augmenting it. Promising intelligence amplification and higher productivity, AR has been intensively researched over several decades but has yet to reach a broad audience.This thesis presents efforts in bringing Augmented Reality to mobile phones and thus to the general public. Implementing technologies on limited devices, such as mobile phones, poses a number of challenges that differ from traditional research directions. These include: limited computational resources with little or no possibility to upgrade or add hardware, limited input and output capabilities for interactive 3D graphics. The research presented in this thesis addresses these challenges and makes contributions in the following areas:Mobile Phone Computer Vision-Based TrackingThe first contribution of thesis has been to migrate computer vision algorithms for tracking the mobile phone camera in a real world reference frame - a key enabling technology for AR. To tackle performance issues, low-level optimized code, using fixed-point algorithms, has been developed.Mobile Phone 3D Interaction TechniquesAnother contribution of this thesis has been to research interaction techniques for manipulating virtual content. This is in part realized by exploiting camera tracking for position-controlled interaction where motion of the device is used as input. Gesture input, made possible by a separate front camera, is another approach that is investigated. The obtained results are not unique to AR and could also be applicable to general mobile 3D graphics.Novel Single User AR ApplicationsWith short range communication technologies, mobile phones can exchange data not only with other phones but also with an intelligent environment. Data can be obtained for tracking or visualization; displays can be used to render graphics with the tracked mobile phone acting as an interaction device. Work is presented where a mobile phone harvests a sensor-network to use AR to visualize live data in context.Novel Collaboration AR ApplicationsOne of the most promising areas for mobile phone based AR is enhancing face-to-face computer supported cooperative work. This is because the AR display permits non-verbal cues to be used to a larger extent. In this thesis, face-to-face collaboration has been researched to examine whether AR increases awareness of collaboration partners even on small devices such as mobile phones. User feedback indicates that this is the case, confirming the hypothesis that mobile phones are increasingly able to deliver an AR experience to a large audience.
9.	Lindholm, Stefan, et al. (författare) Spatial Conditioning of Transfer Functions Using Local Material Distributions 2010 Ingår i: IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS. - : IEEE. - 1077-2626. ; 16:6, s. 1301-1310 Tidskriftsartikel (refereegranskat)abstract In many applications of Direct Volume Rendering (DVR) the importance of a certain material or feature is highly dependent on its relative spatial location. For instance, in the medical diagnostic procedure, the patients symptoms often lead to specification of features, tissues and organs of particular interest. One such example is pockets of gas which, if found inside the body at abnormal locations, are a crucial part of a diagnostic visualization. This paper presents an approach that enhances DVR transfer function design with spatial localization based on user specified material dependencies. Semantic expressions are used to define conditions based on relations between different materials, such as only render iodine uptake when close to liver. The underlying methods rely on estimations of material distributions which are acquired by weighing local neighborhoods of the data against approximations of material likelihood functions. This information is encoded and used to influence rendering according to the users specifications. The result is improved focus on important features by allowing the user to suppress spatially less-important data. In line with requirements from actual clinical DVR practice, the methods do not require explicit material segmentation that would be impossible or prohibitively time-consuming to achieve in most real cases. The scheme scales well to higher dimensions which accounts for multi-dimensional transfer functions and multivariate data. Dual-Energy Computed Tomography, an important new modality in radiology, is used to demonstrate this scalability. In several examples we show significantly improved focus on clinically important aspects in the rendered images.
10.	Ljung, Patric, 1968-, et al. (författare) Forensic Virtual Autopsies by Direct Volume Rendering 2007 Ingår i: IEEE signal processing magazine (Print). - Piscataway, NJ, USA : IEEE. - 1053-5888 .- 1558-0792. ; 24:6, s. 112-116 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract This paper presents state-of-the-art methods, which address the technical challenges in visualizing large three-dimensional (3D) data and enable rendering at interactive frame rates.
11.	Ljung, Patric, 1968-, et al. (författare) Full Body Virtual Autopsies Using A State-of-the-art Volume Rendering Pipeline 2006 Ingår i: IEEE Transactions on Visualization and Computer Graphics. - 1077-2626 .- 1941-0506. ; 12:5, s. 869-876 Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract This paper presents a procedure for virtual autopsies based on interactive 3D visualizations of large scale, high resolutiondata from CT-scans of human cadavers. The procedure is described using examples from forensic medicine and the added valueand future potential of virtual autopsies is shown from a medical and forensic perspective. Based on the technical demands ofthe procedure state-of-the-art volume rendering techniques are applied and refined to enable real-time, full body virtual autopsiesinvolving gigabyte sized data on standard GPUs. The techniques applied include transfer function based data reduction using levelof-detail selection and multi-resolution rendering techniques. The paper also describes a data management component for large,out-of-core data sets and an extension to the GPU-based raycaster for efficient dual TF rendering. Detailed benchmarks of thepipeline are presented using data sets from forensic cases.
12.	Lundin (Palmerius), Karljohan, 1977-, et al. (författare) Enabling design and interactive selection of haptic modes 2007 Ingår i: Virtual Reality. - : Springer Science and Business Media LLC. - 1359-4338 .- 1434-9957. Tidskriftsartikel (refereegranskat)abstract The ever increasing size and complexity of volumetric data in a wide range of disciplines makes it useful to augment volume visualization tools with alternative modalities. Studies have shown that introducing haptics can significantly increase both exploration speed and precision. It is also capable of conveying material properties of data and thus has great potential to improve user performance in volume data exploration. In this paper we describe how recent advances in volume haptics can be used to build haptic modes-building blocks for haptic schemes. These modes have been used as base components of a toolkit allowing for more efficient development of haptic prototypes and applications. This toolkit allows interactive construction, configuration and fine-tuning of both visual and haptic representations of the data. The technology is also used in a pilot study to determine the most important issues and aspects in haptic volume data interaction and exploration, and how the use of haptic modes can facilitate the implementation of effective haptic schemes.
13.	Lundström, Claes, et al. (författare) Multi-Touch Table System for Medical Visualization: Application to Orthopedic Surgery Planning 2011 Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-2626 .- 1941-0506. ; 17:12, s. 1775-1784 Tidskriftsartikel (refereegranskat)abstract Medical imaging plays a central role in a vast range of healthcare practices. The usefulness of 3D visualizations has been demonstrated for many types of treatment planning. Nevertheless, full access to 3D renderings outside of the radiology department is still scarce even for many image-centric specialties. Our work stems from the hypothesis that this under-utilization is partly due to existing visualization systems not taking the prerequisites of this application domain fully into account. We have developed a medical visualization table intended to better fit the clinical reality. The overall design goals were two-fold: similarity to a real physical situation and a very low learning threshold. This paper describes the development of the visualization table with focus on key design decisions. The developed features include two novel interaction components for touch tables. A user study including five orthopedic surgeons demonstrates that the system is appropriate and useful for this application domain.
14.	Lundström, Claes, et al. (författare) State-of-the-art of visualization in post-mortem imaging 2012 Ingår i: Acta Pathologica, Microbiologica et Immunologica Scandinavica (APMIS). - : Wiley-Blackwell. - 0903-4641 .- 1600-0463. ; 120:4, s. 316-326 Forskningsöversikt (refereegranskat)abstract Autopsies constitute a valuable feedback to the healthcare chain to achieve improvements in quality of care and cost effectiveness. This review describes post-mortem imaging, which has emerged as an important part of the pathology toolbox. A broad range of visualization aspects within post-mortem imaging are covered. General state-of-the-art overviews of the components in the visualization pipeline are complemented by in-depth descriptions of methods developed by the authors and our collaborators. The forensic field is represented and related to, as it is spearheading much development in postmortem imaging. Other topics are workflow, imaging data acquisition, and visualization rendering technology. All in all, this review shows the mature state of visual analysis for a non-or minimal-invasive investigation of the deceased patient.
15.	Lundström, Claes, 1973-, et al. (författare) The alpha-histogram: Using Spatial Coherence to Enhance Histograms and Transfer Function Design 2006 Ingår i: Proceedings Eurographics/IEEE Symposium on Visualization 2006, Lisbon, Portugal. ; , s. 227-234 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract The high complexity of Transfer Function (TF) design is a major obstacle to widespread routine use of Direct Volume Rendering, particularly in the case of medical imaging. Both manual and automatic TF design schemes would benefit greatly from a fast and simple method for detection of tissue value ranges. To this end, we introduce the a-histogram, an enhancement that amplifies ranges corresponding to spatially coherent materials. The properties of the a-histogram have been explored for synthetic data sets and then successfully used to detect vessels in 20 Magnetic Resonance angiographies, proving the potential of this approach as a fast and simple technique for histogram enhancement in general and for TF construction in particular.
16.	Lundström, Claes, 1973-, et al. (författare) Uncertainty Visualization in Medical Volume Rendering Using Probabilistic Animation 2007 Ingår i: IEEE Transactions on Visualization and Computer Graphics. - 1077-2626 .- 1941-0506. ; 13:6, s. 1648-1655 Tidskriftsartikel (refereegranskat)abstract Direct volume rendering has proved to be an effective visualization method for medical data sets and has reached wide-spread clinical use. The diagnostic exploration, in essence, corresponds to a tissue classification task, which is often complex and time-consuming. Moreover, a major problem is the lack of information on the uncertainty of the classification, which can have dramatic consequences for the diagnosis. In this paper this problem is addressed by proposing animation methods to convey uncertainty in the rendering. The foundation is a probabilistic Transfer Function model which allows for direct user interaction with the classification. The rendering is animated by sampling the probability domain over time, which results in varying appearance for uncertain regions. A particularly promising application of this technique is a "sensitivity lens" applied to focus regions in the data set. The methods have been evaluated by radiologists in a study simulating the clinical task of stenosis assessment, in which the animation technique is shown to outperform traditional rendering in terms of assessment accuracy.
17.	Nguyen, Tan Khoa, et al. (författare) Concurrent Volume Visualization of Real-Time fMRI 2010 Ingår i: Proceedings of the 8th IEEE/EG International Symposium on Volume Graphics. - Goslar, Germany : Eurographics - European Association for Computer Graphics. - 9783905674231 ; , s. 53-60 Konferensbidrag (refereegranskat)abstract We present a novel approach to interactive and concurrent volume visualization of functional Magnetic Resonance Imaging (fMRI). While the patient is in the scanner, data is extracted in real-time using state-of-the-art signal processing techniques. The fMRI signal is treated as light emission when rendering a patient-specific high resolution reference MRI volume, obtained at the beginning of the experiment. As a result, the brain glows and emits light from active regions. The low resolution fMRI signal is thus effectively fused with the reference brain with the current transfer function settings yielding an effective focus and context visualization. The delay from a change in the fMRI signal to the visualization is approximately 2 seconds. The advantage of our method over standard 2D slice based methods is shown in a user study. We demonstrate our technique through experiments providing interactive visualization to the fMRI operator and also to the test subject in the scanner through a head mounted display.
18.	Ohlsson, Henrik, 1981-, et al. (författare) Enabling Bio-Feedback using Real-Time fMRI 2008 Ingår i: 47th IEEE Conference on Decision and Control, 2008, CDC 2008. - Linköping : IEEE. - 9781424431236 ; , s. 3336-3341 Konferensbidrag (refereegranskat)abstract Despite the enormous complexity of the human mind, fMRI techniques are able to partially observe the state of a brain in action. In this paper we describe an experimental setup for real-time fMRI in a bio-feedback loop. One of the main challenges in the project is to reach a detection speed, accuracy and spatial resolution necessary to attain sufficient bandwidth of communication to close the bio-feedback loop. To this end we have banked on our previous work on real-time filtering for fMRI and system identification, which has been tailored for use in the experiment setup. In the experiments presented the system is trained to estimate where a person in the MRI scanner is looking from signals derived from the visual cortex only. We have been able to demonstrate that the user can induce an action and perform simple tasks with her mind sensed using real-time fMRI. The technique may have several clinical applications, for instance to allow paralyzed and "locked in" people to communicate with the outside world. In the meanwhile, the need for improved fMRI performance and brain state detection poses a challenge to the signal processing community. We also expect that the setup will serve as an invaluable tool for neuro science research in general.
19.	Olsson, Björn, 1975-, et al. (författare) A Novel Approach to Compress Reflection Functions based on PCA 2005 Ingår i: SIGRAD Conference,2005. - Linköping, Sweden : Linköping University Electronic Press. ; , s. 51-, s. 51-56 Konferensbidrag (refereegranskat)
20.	Olsson, Björn, 1975- (författare) Image Based Visualization Methods for Meteorological Data 2004 Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract Visualization is the process of constructing methods, which are able to synthesize interesting and informative images from data sets, to simplify the process of interpreting the data. In this thesis a new approach to construct meteorological visualization methods using neural network technology is described. The methods are trained with examples instead of explicitely designing the appearance of the visualization.This approach is exemplified using two applications. In the fist the problem to compute an image of the sky for dynamic weather, that is taking account of the current weather state, is addressed. It is a complicated problem to tie the appearance of the sky to a weather state. The method is trained with weather data sets and images of the sky to be able to synthesize a sky image for arbitrary weather conditions. The method has been trained with various kinds of weather and images data. The results show that this is a possible method to construct weather visaualizations, but more work remains in characterizing the weather state and further refinement is required before the full potential of the method can be explored. This approach would make it possible to synthesize sky images of dynamic weather using a fast and efficient empirical method.In the second application the problem of computing synthetic satellite images form numerical forecast data sets is addressed. In this case a mode is trained with preclassified satellite images and forecast data sets to be able to synthesize a satellite image representing arbitrary conditions. The resulting method makes it possible to visualize data sets from numerical weather simulations using synthetic satellite images, but could also be the basis for algorithms based on a preliminary cloud classification.
21.	Rauhala, Malinda, et al. (författare) A Novel Interface to Sensor Networks using Handheld Augmented Reality 2006 Ingår i: Proceedings of the 8th Conference on Human-Computer interaction with Mobile Devices and Services, Espoo, Finland. - New York, NY, USA : ACM. ; , s. 145-148 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Augmented Reality technology enables a mobile phone to be used as an x-ray tool, visualizing structures and states not visible to the naked eye. In this paper we evaluate a set of techniques used augmenting the world with a visualization of data from a sensor network. Combining virtual and real information introduces challenges as information from the two domains might interfere. We have applied our system to humidity data and present a user study together with feedback from domain experts. The prototype system can be seen as the first step towards a novel tool for inspection of building elements.
22.	Scandurra, Isabella, 1973-, et al. (författare) Advancing the State-of-the-Art for Virtual Autopsies : Initial Forensic Workflow Study 2010 Ingår i: Studies in Health Technology and Informatics. - : IOS Press. - 0926-9630 .- 1879-8365. ; 160, s. 639-643 Tidskriftsartikel (refereegranskat)abstract There are numerous advantages described of how imaging technology can support forensic examinations. However, postmortem examinations of bodies are mainly performed to address demands which differ from those of traditional clinical image processing. This needs to be kept in mind when gathering information from image data sets for forensic purposes. To support radiologists and forensicclinicians using Virtual Autopsy technologies, an initial workflow study regarding post-mortem imaging has been performed, aiming to receive an improved understanding of how Virtual Autopsyworkstations, image data sets and processes can be adjusted to support and improve conventional autopsies. This paper presents potential impacts and a current forensic Virtual Autopsy workflowaiming to form a foundation for collaborative procedures that increase the value of Virtual Autopsy. The workflow study will provide an increased and mutual understanding of involved professionals. In addition, insight into future forensic workflows based on demands from both forensic and radiologist perspectives bring visualization and medical informatics researchers together to develop and improvethe technology and software needed.
23.	Ynnerman, Anders, et al. (författare) Interactive visualization of 3D scanned mummies at public venues 2016 Ingår i: Communications of the ACM. - : Association for Computing Machinery. - 0001-0782 .- 1557-7317. ; 59:12, s. 72-81 Tidskriftsartikel (refereegranskat)abstract BY COMBINING VISUALIZATION techniques with interactive multi-touch tables and intuitive user interfaces, visitors to museums and science centers can conduct self-guided tours of large volumetric image data. In an interactive learning experience, visitors become the explorers of otherwise invisible interiors of unique artifacts and subjects. Here, we take as our starting point the state of the art in scanning technologies, then discuss the latest research on high-quality interactive volume rendering and how it can be tailored to meet the speci?c demands.
24.	Ynnerman, Anders, 1963-, et al. (författare) Multi-Touch Surfaces and Patient-Specific Data 2021. - 1 Ingår i: Digital Anatomy. - Cham : Springer. - 9783030619046 ; , s. 223-242 Bokkapitel (refereegranskat)abstract While the usefulness of 3D visualizations has been shown for a range of clinical applications such as treatment planning it still had difficulties in being adopted in widespread clinical practice. This chapter describes how multi-touch surfaces with patient-specific data have contributed to breaking this barrier, paving the way for adoption into clinical practice and, at the same time, also found widespread use in educational settings and in communication of science to the general public. The key element identified for this adoption is the string of steps found in the full imaging chain, which will be described as an introduction to the topic in this chapter. Emphasis in the chapter is, however, visualization aspects, e.g., intuitive interaction with patient-specific data captured with the latest high speed and high-quality imaging modalities. A necessary starting point for this discussion is the foundations of and state-of-the-art in volumetric rendering, which form the basis for the underlying theory part of the chapter. The chapter presents two use cases. One case is focusing on the use of multi-touch in medical education and the other is focusing on the use of touch surfaces at public venues, such as science centers and museums.
25.	Ynnerman, Anders, 1963-, et al. (författare) Multi-Touch Table System for Medical Visualization 2015 Ingår i: Eurographics 2015. - : Eurographics - European Association for Computer Graphics. Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Medical imaging plays a central role in a vast range of healthcare practices. While the usefulness of 3D visualizations is well known, the adoption of such technology has previously been limited in many medical areas. This paper, awarded the Dirk Bartz Prize for Visual Computing in Medicine 2015, describes the development of a medical multi-touch visualization table that successfully has reached its aim to bring 3D visualization to a wider clinical audience. The descriptions summarize the targeted clinical scenarios, the key characteristics of the system, and the user feedback obtained.
26.	Axelsson, Emil, et al. (författare) Dynamic Scene Graph: Enabling Scaling, Positioning, and Navigation in the Universe 2017 Ingår i: Computer graphics forum (Print). - : WILEY. - 0167-7055 .- 1467-8659. ; 36:3, s. 459-468 Tidskriftsartikel (refereegranskat)abstract In this work, we address the challenge of seamlessly visualizing astronomical data exhibiting huge scale differences in distance, size, and resolution. One of the difficulties is accurate, fast, and dynamic positioning and navigation to enable scaling over orders of magnitude, far beyond the precision of floating point arithmetic. To this end we propose a method that utilizes a dynamically assigned frame of reference to provide the highest possible numerical precision for all salient objects in a scene graph. This makes it possible to smoothly navigate and interactively render, for example, surface structures on Mars and the Milky Way simultaneously. Our work is based on an analysis of tracking and quantification of the propagation of precision errors through the computer graphics pipeline using interval arithmetic. Furthermore, we identify sources of precision degradation, leading to incorrect object positions in screen-space and z-fighting. Our proposed method operates without near and far planes while maintaining high depth precision through the use of floating point depth buffers. By providing interoperability with order-independent transparency algorithms, direct volume rendering, and stereoscopy, our approach is well suited for scientific visualization. We provide the mathematical background, a thorough description of the method, and a reference implementation.
27.	Axholt, Magnus, et al. (författare) Accuracy of Eyepoint Estimation in Optical See-Through Head-Mounted Displays Using the Single Point Active Alignment Method 2011 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract This paper studies the accuracy of the estimated eyepoint of an Optical See-Through Head-Mounted Display (OST HMD) calibrated using the Single Point Active Alignment Method (SPAAM). Quantitative evaluation of calibration procedures for OST HMDs is complicated as it is currently not possible to share the subject’s view. Temporarily replacing the subject’s eye with a camera during the calibration or evaluation stage has been proposed, but the uncertainty of a correct eyepoint estimation remains. In the experiment reported in this paper, subjects were used for all stages of calibration and the results were verified with a 3D measurement device. The nine participants constructed 25 visual alignments per calibration after which the estimated pinhole camera model was decomposed into its intrinsic and extrinsic parameters using two common methods. Unique to this experiment, compared to previous evaluations, is the measurement device used to cup the subject’s eyeball. It measures the eyepoint location relative to the head tracker, thereby establishing the calibration accuracy of the estimated eyepoint location. As the results on accuracy are expressed as individual pinhole camera parameters, rather than a compounded registration error, this paper complements previously published work on parameter variance as the former denotes bias and the latter represents noise. Results indicate that the calibrated eyepoint is on average 5 cm away from its measured location and exhibits a vertical bias which potentially causes dipvergence for stereoscopic vision for objects located further away than 5.6 m. Lastly, this paper closes with a discussion on the suitability of the traditional pinhole camera model for OST HMD calibration.
28.	Axholt, Magnus, et al. (författare) Optical See-Through Head Mounted Display : Direct Linear Transformation Calibration Robustness in the Presence of User Alignment Noise 2010 Ingår i: Proceedings of the 54th Annual Meeting of the Human Factors and Ergonomics Society. - Linköping : Linköping University Electronic Press. - 9780945289371 Konferensbidrag (refereegranskat)abstract The correct spatial registration between virtual and real objects in optical see-through augmented reality implies accurate estimates of the user’s eyepoint relative to the location and orientation of the display surface. A common approach is to estimate the display parameters through a calibration procedure involving a subjective alignment exercise. Human postural sway and targeting precision contribute to imprecise alignments, which in turn adversely affect the display parameter estimation resulting in registration errors between virtual and real objects. The technique commonly used has its origin incomputer vision, and calibrates stationary cameras using hundreds of correspondence points collected instantaneously in one video frame where precision is limited only by pixel quantization and image blur. Subsequently the input noise level is several order of magnitudes greater when a human operator manually collects correspondence points one by one. This paper investigates the effect of human alignment noise on view parameter estimation in an optical see-through head mounted display to determine how well astandard camera calibration method performs at greater noise levels than documented in computer vision literature. Through Monte-Carlo simulations we show that it is particularly difficult to estimate the user’s eyepoint in depth, but that a greater distribution of correspondence points in depth help mitigate the effects of human alignment noise.
29.	Axholt, Magnus, et al. (författare) Parameter Estimation Variance of the Single Point Active Alignment Method in Optical See-Through Head Mounted Display Calibration 2011 Ingår i: Proceedings of the IEEE Virtual Reality Conference. - Piscataway, NJ, USA : IEEE. - 9781457700378 - 9781457700392 ; , s. 27-24 Konferensbidrag (refereegranskat)abstract The parameter estimation variance of the Single Point Active Alignment Method (SPAAM) is studied through an experiment where 11 subjects are instructed to create alignments using an Optical See-Through Head Mounted Display (OSTHMD) such that three separate correspondence point distributions are acquired. Modeling the OSTHMD and the subject's dominant eye as a pinhole camera, findings show that a correspondence point distribution well distributed along the user's line of sight yields less variant parameter estimates. The estimated eye point location is studied in particular detail. Thefindings of the experiment are complemented with simulated datawhich show that image plane orientation is sensitive to the numberof correspondence points. The simulated data also illustrates someinteresting properties on the numerical stability of the calibrationproblem as a function of alignment noise, number of correspondencepoints, and correspondence point distribution.
30.	Axholt, Magnus, 1978- (författare) Pinhole Camera Calibration in the Presence of Human Noise 2011 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract The research work presented in this thesis is concerned with the analysis of the human body as a calibration platform for estimation of a pinhole camera model used in Augmented Reality environments mediated through Optical See-Through Head-Mounted Display. Since the quality of the calibration ultimately depends on a subject’s ability to construct visual alignments, the research effort is initially centered around user studies investigating human-induced noise, such as postural sway and head aiming precision. Knowledge about subject behavior is then applied to a sensitivity analysis in which simulations are used to determine the impact of user noise on camera parameter estimation.Quantitative evaluation of the calibration procedure is challenging since the current state of the technology does not permit access to the user’s view and measurements in the image plane as seen by the user. In an attempt to circumvent this problem, researchers have previously placed a camera in the eye socket of a mannequin, and performed both calibration and evaluation using the auxiliary signal from the camera. However, such a method does not reflect the impact of human noise during the calibration stage, and the calibration is not transferable to a human as the eyepoint of the mannequin and the intended user may not coincide. The experiments performed in this thesis use human subjects for all stages of calibration and evaluation. Moreover, some of the measurable camera parameters are verified with an external reference, addressing not only calibration precision, but also accuracy.
31.	Bae, S. Sandra, et al. (författare) A Computational Design Pipeline to Fabricate Sensing Network Physicalizations 2024 Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : IEEE COMPUTER SOC. - 1077-2626 .- 1941-0506. ; 30:1, s. 913-923 Tidskriftsartikel (refereegranskat)abstract Interaction is critical for data analysis and sensemaking. However, designing interactive physicalizations is challenging as it requires cross-disciplinary knowledge in visualization, fabrication, and electronics. Interactive physicalizations are typically produced in an unstructured manner, resulting in unique solutions for a specific dataset, problem, or interaction that cannot be easily extended or adapted to new scenarios or future physicalizations. To mitigate these challenges, we introduce a computational design pipeline to 3D print network physicalizations with integrated sensing capabilities. Networks are ubiquitous, yet their complex geometry also requires significant engineering considerations to provide intuitive, effective interactions for exploration. Using our pipeline, designers can readily produce network physicalizations supporting selection-the most critical atomic operation for interaction-by touch through capacitive sensing and computational inference. Our computational design pipeline introduces a new design paradigm by concurrently considering the form and interactivity of a physicalization into one cohesive fabrication workflow. We evaluate our approach using (i) computational evaluations, (ii) three usage scenarios focusing on general visualization tasks, and (iii) expert interviews. The design paradigm introduced by our pipeline can lower barriers to physicalization research, creation, and adoption.
32.	Besançon, Lonni, et al. (författare) Exploring and Explaining Climate Change: Exploranation as a Visualization Pedagogy for Societal Action 2022 Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract Engaging mass audiences with crucial societal issues, such as cli-mate change, can be provided through interactive exhibits designed around the paradigm of exploranation. We present example inter-active installations in the newly founded Wadstr¨oms Exploranation Laboratory that explain various aspects of climate change while allowing public participants to explore the real scientific data. We describe how effects and causes of climate change can be communi-cated by two of the installations that allow for interactive opportuni-ties to explore the underlying data while gaining insight into climate change sources and effects. We close with implications for future work on exploranation as an emerging visualization pedagogy in public spaces.
33.	Besançon, Lonni, et al. (författare) The State of the Art of Spatial Interfaces for 3D Visualization 2021 Ingår i: Computer graphics forum (Print). - : WILEY. - 0167-7055 .- 1467-8659. ; 40:1, s. 293-326 Tidskriftsartikel (refereegranskat)abstract We survey the state of the art of spatial interfaces for 3D visualization. Interaction techniques are crucial to data visualization processes and the visualization research community has been calling for more research on interaction for years. Yet, research papers focusing on interaction techniques, in particular for 3D visualization purposes, are not always published in visualization venues, sometimes making it challenging to synthesize the latest interaction and visualization results. We therefore introduce a taxonomy of interaction technique for 3D visualization. The taxonomy is organized along two axes: the primary source of input on the one hand and the visualization task they support on the other hand. Surveying the state of the art allows us to highlight specific challenges and missed opportunities for research in 3D visualization. In particular, we call for additional research in: (1) controlling 3D visualization widgets to help scientists better understand their data, (2) 3D interaction techniques for dissemination, which are under-explored yet show great promise for helping museum and science centers in their mission to share recent knowledge, and (3) developing new measures that move beyond traditional time and errors metrics for evaluating visualizations that include spatial interaction.
34.	Bivall, Petter, 1979- (författare) Touching the Essence of Life : Haptic Virtual Proteins for Learning 2010 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract This dissertation presents research in the development and use of a multi-modal visual and haptic virtual model in higher education. The model, named Chemical Force Feedback (CFF), represents molecular recognition through the example of protein-ligand docking, and enables students to simultaneously see and feel representations of the protein and ligand molecules and their force interactions. The research efforts have been divided between educational research aspects and development of haptic feedback techniques.The CFF model was evaluated in situ through multiple data-collections in a university course on molecular interactions. To isolate possible influences of haptics on learning, half of the students ran CFF with haptics, and the others used the equipment with force feedback disabled. Pre- and post-tests showed a significant learning gain for all students. A particular influence of haptics was found on students reasoning, discovered through an open-ended written probe where students' responses contained elaborate descriptions of the molecular recognition process.Students' interactions with the system were analyzed using customized information visualization tools. Analysis revealed differences between the groups, for example, in their use of visual representations on offer, and in how they moved the ligand molecule. Differences in representational and interactive behaviours showed relationships with aspects of the learning outcomes.The CFF model was improved in an iterative evaluation and development process. A focus was placed on force model design, where one significant challenge was in conveying information from data with large force differences, ranging from very weak interactions to extreme forces generated when atoms collide. Therefore, a History Dependent Transfer Function (HDTF) was designed which adapts the translation of forces derived from the data to output forces according to the properties of the recently derived forces. Evaluation revealed that the HDTF improves the ability to haptically detect features in volumetric data with large force ranges.To further enable force models with high fidelity, an investigation was conducted to determine the perceptual Just Noticeable Difference (JND) in force for detection of interfaces between features in volumetric data. Results showed that JNDs vary depending on the magnitude of the forces in the volume and depending on where in the workspace the data is presented.
35.	Bivall Persson, Petter, 1979-, et al. (författare) Designing and Evaluating a Haptic System for Biomolecular Education 2007 Ingår i: IEEE Virtual Reality Conference, 2007. VR '07.. - Piscataway, NJ, USA : IEEE. - 1424409063 ; , s. 171-178 Konferensbidrag (refereegranskat)abstract In this paper we present an in situ evaluation of a haptic system, with a representative test population, we aim to determine what, if any, benefit haptics can have in a biomolecular education context. We have developed a haptic application for conveying concepts of molecular interactions, specifically in protein-ligand docking. Utilizing a semi-immersive environment with stereo graphics, users are able to manipulate the ligand and feel its interactions in the docking process. The evaluation used cognitive knowledge tests and interviews focused on learning gains. Compared with using time efficiency as the single quality measure this gives a better indication of a system's applicability in an educational environment. Surveys were used to gather opinions and suggestions for improvements. Students do gain from using the application in the learning process but the learning appears to be independent of the addition of haptic feedback. However the addition of force feedback did decrease time requirements and improved the students understanding of the docking process in terms of the forces involved, as is apparent from the students' descriptions of the experience. The students also indicated a number of features which could be improved in future development.
36.	Bivall Persson, Petter, 1979-, et al. (författare) Evaluating the Effectiveness of Haptic Visualization in Biomolecular Education - Feeling Molecular Specificity in a Docking Task 2006 Ingår i: 12th IOSTE Symposium. - : Universiti Science Malaysia. - 9832700396 ; , s. 745-752 Konferensbidrag (refereegranskat)abstract Within the molecular life sciences extensive use is made of visual representations, ranging from sketches to advanced computer graphics, often used to convey abstract knowledge that is difficult for the student to grasp. This work evaluates a new visual and haptic (tactile/kinetic) tool for protein docking in an in situ learning situation by combining qualitative and quantitative methods, performing tests and interviews with students; all aiming at a proper inclusion of visualization tools into biomolecular education. Preliminary results indicate time gains, strong positive affective responses and learning gains from the tasks, however the influence of haptics needs further investigation.
37.	Bivall Persson, Petter, 1979-, et al. (författare) Improved Feature Detection over Large Force Ranges Using History Dependent Transfer Functions 2009 Ingår i: Third Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environments and Teleoperator Systems, WorldHaptics 2009. - : IEEE. - 9781424438587 ; , s. 476-481 Konferensbidrag (refereegranskat)abstract In this paper we present a history dependent transfer function (HDTF) as a possible approach to enable improved haptic feature detection in high dynamic range (HDR) volume data. The HDTF is a multi-dimensional transfer function that uses the recent force history as a selection criterion to switch between transfer functions, thereby adapting to the explored force range. The HDTF has been evaluated using artificial test data and in a realistic application example, with the HDTF applied to haptic protein-ligand docking. Biochemistry experts performed docking tests, and expressed that the HDTF delivers the expected feedback across a large force magnitude range, conveying both weak attractive and strong repulsive protein-ligand interaction forces. Feature detection tests have been performed with positive results, indicating that the HDTF improves the ability of feature detection in HDR volume data as compared to a static transfer function covering the same range.
38.	Bivall Persson, Petter, 1979-, et al. (författare) Use of Chemical Force Feedback for Multisensory Insights into Ligand Docking 2007 Ingår i: VII European Symposium of The Protein Society. ; , s. 151-151 Konferensbidrag (refereegranskat)
39.	Bladin, Kalle, et al. (författare) Globe Browsing: Contextualized Spatio-Temporal Planetary Surface Visualization 2018 Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-2626 .- 1941-0506. ; 24:1, s. 802-811 Tidskriftsartikel (refereegranskat)abstract Results of planetary mapping are often shared openly for use in scientific research and mission planning. In its raw format, however, the data is not accessible to non-experts due to the difficulty in grasping the context and the intricate acquisition process. We present work on tailoring and integration of multiple data processing and visualization methods to interactively contextualize geospatial surface data of celestial bodies for use in science communication. As our approach handles dynamic data sources, streamed from online repositories, we are significantly shortening the time between discovery and dissemination of data and results. We describe the image acquisition pipeline, the pre-processing steps to derive a 2.5D terrain, and a chunked level-of-detail, out-of-core rendering approach to enable interactive exploration of global maps and high-resolution digital terrain models. The results are demonstrated for three different celestial bodies. The first case addresses high-resolution map data on the surface of Mars. A second case is showing dynamic processes. such as concurrent weather conditions on Earth that require temporal datasets. As a final example we use data from the New Horizons spacecraft which acquired images during a single flyby of Pluto. We visualize the acquisition process as well as the resulting surface data. Our work has been implemented in the OpenSpace software [8], which enables interactive presentations in a range of environments such as immersive dome theaters. interactive touch tables. and virtual reality headsets.
40.	Bock, Alexander, 1985-, et al. (författare) OpenSpace : An open-source astrovisualization framework 2017 Ingår i: Journal of Open Source Software. - : The Open Journal. - 2475-9066. ; 2:15 Tidskriftsartikel (refereegranskat)abstract OpenSpace (2017; Bock et al. 2017)is an open source interactive data visualization software designed to visualize the entire known universe and portray our ongoing efforts to investigate the cosmos (Bladin, Karl and Axelsson, Emil and Broberg, Erik and Emmart, Carter and Ljung, Patric and Bock, Alexander and Ynnerman, Anders 2017; Bock, Pembroke, et al. 2015). Bringing the latest techniques from data visualization research to the general public and scientists (Bock, Marcinkowski, et al. 2015), OpenSpace supports interactive presentation of dynamic data from observations, simulations, and space mission planning and operations over a large span of sizes (Axelsson, Emil and Costa, Jonathas and Silva, Cláudio T. and Emmart, Carter and Bock, Alexander and Ynnerman, Anders 2017). The software supports multiple operating systems with an extensible architecture powering high resolution tiled displays, planetarium domes, as well as desktop computers. In addition, OpenSpace enables simultaneous connections across the globe creating opportunity for shared experiences among audiences worldwide.
41.	Bock, Alexander, 1985-, et al. (författare) OpenSpace : A System for Astrographics 2020 Ingår i: IEEE Transactions on Visualization and Computer Graphics. - : Institute of Electrical and Electronics Engineers (IEEE). - 1077-2626 .- 1941-0506. ; 26:1, s. 633-642 Tidskriftsartikel (refereegranskat)abstract Human knowledge about the cosmos is rapidly increasing as instruments and simulations are generating new data supporting the formation of theory and understanding of the vastness and complexity of the universe. OpenSpace is a software system that takes on the mission of providing an integrated view of all these sources of data and supports interactive exploration of the known universe from the millimeter scale showing instruments on spacecrafts to billions of light years when visualizing the early universe. The ambition is to support research in astronomy and space exploration, science communication at museums and in planetariums as well as bringing exploratory astrographics to the class room. There is a multitude of challenges that need to be met in reaching this goal such as the data variety, multiple spatio-temporal scales, collaboration capabilities, etc. Furthermore, the system has to be flexible and modular to enable rapid prototyping and inclusion of new research results or space mission data and thereby shorten the time from discovery to dissemination. To support the different use cases the system has to be hardware agnostic and support a range of platforms and interaction paradigms. In this paper we describe how OpenSpace meets these challenges in an open source effort that is paving the path for the next generation of interactive astrographics.
42.	Bock, Alexander, 1985-, et al. (författare) OpenSpace: An Open-Source Framework for Data Visualization and Contextualization 2015 Konferensbidrag (refereegranskat)abstract We present an open-source software development effort called OpenSpace that is tailored for the dissemination of space-related data visualization. In the current stages of the project, we have focussed on the public dissemination of space missions (Rosetta and New Horizons) as well as the support of space weather forecasting. The presented work will focus on the latter of these foci and elaborate on the efforts that have gone into developing a system that allows the user to assess the accuracy and validity of ENLIL ensemble simulations. It becomes possible to compare the results of ENLIL CME simulations with STEREO and SOHO images using an optical flow algorithm. This allows the user to compare velocities in the volumetric rendering of ENLIL data with the movement of CMEs through the field-of-views of various instruments onboard the space craft. By allowing the user access to these comparisons, new information about the time evolution of CMEs through the interplanetary medium is possible. Additionally, contextualizing this information in three-dimensional rendering scene, allows the analyst and the public to disseminate this data. This dissemination is further improved by the ability to connect multiple instances of the software and, thus, reach a broader audience. In a second step, we plan to combine the two foci of the project to enable the visualization of the SWAP instrument onboard New Horizons in context with a far-reaching ENLIL simulation, thus providing additional information about the solar wind dynamics of the outer solar system. The initial work regarding this plan will be presented.
43.	Bock, Alexander, 1985-, et al. (författare) OpenSpace: Bringing NASA Missions to the Public 2018 Ingår i: IEEE Computer Graphics and Applications. - : IEEE COMPUTER SOC. - 0272-1716 .- 1558-1756. ; 38:5, s. 112-118 Tidskriftsartikel (refereegranskat)abstract This viewpoint presents OpenSpace, an open-source astrovisualization software project designed to bridge the gap between scientific discoveries and their public dissemination. A wealth of data exists for space missions from NASA and other sources. OpenSpace brings together this data and combines it in a range of immersive settings. Through non-linear storytelling and guided exploration, interactive immersive experiences help the public to engage with advanced space mission data and models, and thus be better informed and educated about NASA missions, the solar system and outer space. We demonstrate this capability by exploring the OSIRIS-Rex mission.
44.	Bock, Alexander, 1985-, et al. (författare) OpenSpace: Changing the Narrative of Public Dissemination in Astronomical Visualization from What to How 2018 Ingår i: IEEE Computer Graphics and Applications. - : IEEE COMPUTER SOC. - 0272-1716 .- 1558-1756. ; 38:3, s. 44-57 Tidskriftsartikel (refereegranskat)abstract This article presents the development of open-source software called OpenSpace that bridges the gap between scientific discoveries and public dissemination and thus paves the way for the next generation of science communication and data exploration. The article describes how the platform enables interactive presentations of dynamic and time-varying processes by domain experts to the general public. The concepts are demonstrated through four cases: Image acquisitions of the New Horizons and Rosetta spacecraft, the dissemination of space weather phenomena, and the display of high-resolution planetary images. Each case has been presented at public events with great success. These cases highlight the details of data acquisition, rather than presenting the final results, showing the audience the value of supporting the efforts of the scientific discovery.
45.	Bock, Alexander, 1985-, et al. (författare) OpenSpace: Public Dissemination of Space Mission Profiles 2015 Ingår i: 2015 IEEE Scientific Visualization Conference (SciVis). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467397858 ; , s. 141-142 Konferensbidrag (refereegranskat)abstract This work presents a visualization system and its application to space missions. The system allows the public to disseminate the scientific findings of space craft and gain a greater understanding thereof. Instruments field-of-views and their measurements are embedded in an accurate 3 dimensional rendering of the solar system to provide context to past measurements or the planning of future events. We tested our system with NASAs New Horizons at the Pluto Pallooza event in New York and will expose it to the greater public on the upcoming July 14th Pluto flyby.
46.	Bock, Alexander, 1985- (författare) Tailoring visualization applications for tasks and users 2018 Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract Exponential increases in available computational resources over the recent decades have fueled an information explosion in almost every scientific field. This has led to a societal change shifting from an information-poor research environment to an over-abundance of information. As many of these cases involve too much information to directly comprehend, visualization proves to be an effective tool to gain insight into these large datasets. While visualization has been used since the beginning of mankind, its importance is only increasing as the exponential information growth widens the difference between the amount of gathered data and the relatively constant human ability to ingest information. Visualization, as a methodology and tool of transforming complex data into an intuitive visual representation can leverage the combined computational resources and the human cognitive capabilities in order to mitigate this growing discrepancy.A large portion of visualization research is, directly or indirectly, targets users in an application domain, such as medicine, biology, physics, or others. Applied research is aimed at the creation of visualization applications or systems that solve a specific problem within the domain. Combining prior research and applying it to a concrete problem enables the possibility to compare and determine the usability and usefulness of existing visualization techniques. These applications can only be effective when the domain experts are closely involved in the design process, leading to an iterative workflow that informs its form and function. These visualization solutions can be separated into three categories: Exploration, in which users perform an initial study of data, Analysis, in which an established technique is repeatedly applied to a large number of datasets, and Communication in which findings are published to a wider public audience.This thesis presents five examples of application development in finite element modeling, medicine, urban search & rescue, and astronomy and astrophysics. For the finite element modeling, an exploration tool for simulations of stress tensors in a human heart uses a compression method to achieve interactive frame rates. In the medical domain, an analysis system aimed at guiding surgeons during Deep Brain Stimulation interventions fuses multiple modalities in order to improve their outcome. A second analysis application is targeted at the Urban Search & Rescue community supporting the extraction of injured victims and enabling a more sophisticated decision making strategy. For the astronomical domain, first, an exploration application enables the analysis of time-varying volumetric plasma simulations to improving these simulations and thus better predict space weather. A final system focusses on combining all three categories into a single application that enables the same tools to be used for Exploration, Analysis, and Communication, thus requiring the handling of large coordinate systems, and high-fidelity rendering of planetary surfaces and spacecraft operations.
47.	Bock, Alexander, 1985-, et al. (författare) VCMass: A Framework for Verification of Coronal Mass Ejection Ensemble Simulations 2014 Konferensbidrag (refereegranskat)abstract Supporting the growing field of space weather forecasting, we propose a framework to analyze ensemble simulations of coronal mass ejections. As the current simulation technique requires manual input, uncertainty is introduced into the simulation pipeline which leads to inaccurate predictions. Using our system, the analyst can compare ensemble members against ground truth data (arrival time and geo-effectivity) as well as information derived from satellite imagery. The simulations can be compared on a global basis, based on time-resolved quality measures, and as a 3D volumetric rendering with embedded satellite imagery in a multi-view setup. This flexible framework provides the expert with the tools to increase the knowledge about the, as of yet not fully understood, principles behind the formation of coronal mass ejections.
48.	Bock, Alexander, 1985-, et al. (författare) Visual Verification of Space Weather Ensemble Simulations 2015 Ingår i: 2015 IEEE Scientific Visualization Conference (SciVis). - : IEEE. - 9781467397858 ; , s. 17-24 Konferensbidrag (refereegranskat)abstract We propose a system to analyze and contextualize simulations of coronal mass ejections. As current simulation techniques require manual input, uncertainty is introduced into the simulation pipeline leading to inaccurate predictions that can be mitigated through ensemble simulations. We provide the space weather analyst with a multi-view system providing visualizations to: 1. compare ensemble members against ground truth measurements, 2. inspect time-dependent information derived from optical flow analysis of satellite images, and 3. combine satellite images with a volumetric rendering of the simulations. This three-tier workflow provides experts with tools to discover correlations between errors in predictions and simulation parameters, thus increasing knowledge about the evolution and propagation of coronal mass ejections that pose a danger to Earth and interplanetary travel
49.	Bourgois, Marc, et al. (författare) Interactive and Immersive 3D Visualization for ATC 2005 Ingår i: USA/Europe Seminar on Air Traffic Management Research and Development,2005. - Washinton, DC, USA : FAA. ; , s. 303-, s. 27-42 Konferensbidrag (refereegranskat)
50.	Broman, Emma, et al. (författare) ExoplanetExplorer: Contextual Visualization of Exoplanet Systems 2023 Ingår i: 2023 IEEE VISUALIZATION AND VISUAL ANALYTICS, VIS. - : IEEE COMPUTER SOC. - 9798350325577 - 9798350325584 ; , s. 81-85 Konferensbidrag (refereegranskat)abstract An exoplanet is a planet outside of our solar system. Researchers study known exoplanets and gather data about them through observations and derived data. Ongoing efforts involve finding planets with an environment that supports life, which likely exists in what is known as the habitable zone around a star. Through a participatory design process, we developed a tool that enables the exploration of exoplanet attribute data and provides contextual visual information in a 3D spatial view that seamlessly presents

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