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  • 1.
    Axholt, Magnus
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Skoglund, Martin A.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    O’Connell, Stephen D.
    Swedish Air Force Combat Simulation Center at the Swedish Defence Research Agency.
    Cooper, Matthew D.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ellis, Stephen R.
    Human Systems Integration Division at NASA Ames Research Center.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Accuracy of Eyepoint Estimation in Optical See-Through Head-Mounted Displays Using the Single Point Active Alignment Method2011Conference paper (Other academic)
    Abstract [en]

    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.

  • 2.
    Axholt, Magnus
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Skoglund, Martin
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    O'Connell, Stephen
    Swedish Defence Research Agency.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ellis, Stephen
    NASA Ames Research Center.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Parameter Estimation Variance of the Single Point Active Alignment Method in Optical See-Through Head Mounted Display Calibration2011In: Proceedings of the IEEE Virtual Reality Conference / [ed] Michitaka Hirose, Benjamin Lok, Aditi Majumder and Dieter Schmalstieg, Piscataway, NJ, USA: IEEE , 2011, p. 27-24Conference paper (Refereed)
    Abstract [en]

    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.

  • 3.
    Axholt, Magnus
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Skoglund, Martin
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Peterson, Stephen
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Schön, Thomas
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gustafsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Ellis, Stephen
    NASA Ames Research Center, USA.
    Optical See-Through Head Mounted Display: Direct Linear Transformation Calibration Robustness in the Presence of User Alignment Noise2010Report (Other academic)
    Abstract [en]

    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.

  • 4.
    Axholt, Magnus
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Skoglund, Martin
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Peterson, Stephen
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Schön, Thomas
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Gustafsson, Fredrik
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ellis, Stephen
    NASA Ames Research Center, USA.
    Optical See-Through Head Mounted Display: Direct Linear Transformation Calibration Robustness in the Presence of User Alignment Noise2010In: Proceedings of the 54th Annual Meeting of the Human Factors and Ergonomics Society, 2010Conference paper (Refereed)
    Abstract [en]

    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.

  • 5.
    Bivall Persson, Petter
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology. Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Tibell, Lena
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Visuella och haptiska modeller för underlättad förståelse för molekylers struktur och interaktioner2007In: 10:e Universitetspedagogiska konferensen vid Linköpings universitet: Pedagogiska utmaningar i tiden / [ed] Helene Hård af Segerstad, 2007, p. 43-47Conference paper (Refereed)
  • 6.
    Bivall Persson, Petter
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Tibell, Lena
    Linköping University, Department of Biomedicine and Surgery, Division of cell biology. Linköping University, Faculty of Health Sciences.
    Ainsworth, Shaaron
    Learning Sciences Research Institute, University of Nottingham, Nottingham, UK.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Jonsson, Bengt-Harald
    Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology. Linköping University, The Institute of Technology.
    Designing and Evaluating a Haptic System for Biomolecular Education2007In: IEEE Virtual Reality Conference, 2007. VR '07. / [ed] Sherman, W; Lin, M; Steed, A, Piscataway, NJ, USA: IEEE , 2007, p. 171-178Conference paper (Refereed)
    Abstract [en]

    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.

  • 7.
    Bivall Persson, Petter
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Jonsson, Bengt-Harald
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology.
    Tibell, Lena
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Use of Chemical Force Feedback for Multisensory Insights into Ligand Docking2007In: VII European Symposium of The Protein Society: From Proteins to Proteome, 2007, p. 151-151Conference paper (Refereed)
  • 8.
    Bivall Persson, Petter
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Höst, Gunnar E.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew D.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Tibell, Lena A. E.
    Linköping University, Department of Clinical and Experimental Medicine. Linköping University, Faculty of Health Sciences.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Improved Feature Detection over Large Force Ranges Using History Dependent Transfer Functions2009In: Third Joint Eurohaptics Conference and Symposium on Haptic Interfaces for Virtual Environments and Teleoperator Systems, WorldHaptics 2009, IEEE , 2009, p. 476-481Conference paper (Refereed)
    Abstract [en]

    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.

  • 9.
    Bivall Persson, Petter
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology. Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Tibell, Lena
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Using Force Feedback Virtual Reality Technology as a Tactile Gateway to Understanding of Biomolecular Interactions2006In: 9th JURE conference of EARLI, 2006Conference paper (Other academic)
  • 10.
    Bivall Persson, Petter
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology. Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA).
    Tibell, Lena
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Cooper, Matthew D.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ainsworth, Shaaron
    Learning Sciences Research Institute University of Nottingham.
    Reasoning through Touch? Using Haptics in Life Science Education2007In: EARLI 2007 12th Biennial Conference for Research on Learning and Instruction, 2007Conference paper (Other academic)
  • 11.
    Bivall Persson, Petter
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Tibell, Lena
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Biomedicine and Surgery, Division of cell biology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Jonsson, Bengt-Harald
    Linköping University, The Institute of Technology. Linköping University, Department of Physics, Chemistry and Biology, Molecular Biotechnology.
    Evaluating the Effectiveness of Haptic Visualization in Biomolecular Education - Feeling Molecular Specificity in a Docking Task2006In: 12th IOSTE Symposium, Universiti Science Malaysia , 2006, p. 745-752Conference paper (Refereed)
    Abstract [en]

    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.

  • 12.
    Bourgois, Marc
    et al.
    INO Eurocontrol Experimental Centre.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Duong, Vu
    UNO Eurocontrol Experimental Centre.
    Hjalmarsson, Jonas
    Linköping University, Department of Science and Technology.
    Lange, Marcus
    Linköping University, Department of Science and Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Interactive and Immersive 3D Visualization for ATC2005In: USA/Europe Seminar on Air Traffic Management Research and Development,2005, Washinton, DC, USA: FAA , 2005, p. 303-Conference paper (Refereed)
  • 13.
    Cooper, Matthew
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Fridlund, Alexander
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Andel, Miroslav
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Bojan, Claudiu
    Eurocontrol, Luxembourg.
    Hardy, Jean-Luc
    Eurocontrol Experimental Centre, Brétigny.
    Educational Benefits of 3D Displays in Early Controller Training2010In: Proceedings of the 27th International Congress of the Aeronautical Sciences (ICAS2010) / [ed] Professor Ian Grant, 2010Conference paper (Other academic)
    Abstract [en]

    There have been many attempts to exploit three- dimensional displays in Air Traffic Control where it has long been suspected that the 3D display may help to reduce the cognitive load on the controller by removing the need to construct an elaborate mental model of the air space and the traffic contained within it. 3D displays could allow the controller to simply re-interpret the presented information in real time without the need for them to construct this internal model and without the need to remember large amounts of complex information. This should result in controllers being able to manage larger numbers of aircraft without loss of safety, as well as reducing the pressure on controllers allowing for longer work sessions with less problems of mental fatigue.

    The purpose of this study has been to explore the use of 3D in controller training and, in this initial study, to examine the basic reaction of the controllers to 3D representations and the effects, if any, which the introduction of 3D has on their work.

  • 14.
    Dang, Nguyen Thong
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Cooper, Matthew D.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Bourgois, Marc
    EUROCONTROL Experimental Centre, France.
    A Survey on Controller Weather Information Needs and 3D Weather Visualization2006In: EUROCONTROL Innovative Research Workshop,2006, Bruxelles, BE: EUROCONTROL , 2006, p. 69-79Conference paper (Other academic)
  • 15.
    Dang, Nguyen Thong
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Cooper, Matthew D.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Bourgois, Marc
    EUROCONTROL Experimental Centre, France.
    Design of an Evaluation on Multimodal Interaction in a 3D Visualization Environment for Air Traffic Control2006In: Visualization and Distributed System Technologies: the AD4 Approach and Beyond,2006, 2006, p. 122-135Conference paper (Other academic)
  • 16.
    Dang, Nguyen Thong
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Tavanti, Monica
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Rankin, Ivan
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    A comparison of different input devices for a 3D environment2007In: European Conference on Cognitive Ergonomics 2007,2007, London: ACM Press , 2007, p. 153-Conference paper (Refereed)
    Abstract [en]

    Motivation - To identify a suitable interaction modality -among the ones currently implemented in a three-dimensional (3D) environment for Air Traffic Control- for allowing interactive exploration of and gathering information about 3D weather structures. Research approach - A usability study entailing four interaction modalities (also called -interaction interfaces-): voice, wand, pen and sketch interfaces, across a task requiring 3D surface exploration, information gathering and recall of information. Quantitative data (time, errors and a composite performance index) as well as qualitative data were collected. Findings/Design - Overall, the results indicate that the wand supported a better performance when compared to the other interaction interfaces. Among the four interaction interfaces, the voice interface seems to present additional limitations, mostly related to time lag in the voice recognition, that were judged as a source of frustration. Originality/Value - The present work provides empirical results deriving from a comparative usability study of four interaction interfaces; it contributes to the study of interaction in 3D environments with new empirical data.

  • 17.
    Ericsson, Daniel
    et al.
    ITN Undergraduate LiU.
    Johansson, Jimmy
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Visual Data Analysis using Tracked Statistical Measures within Parallel Coordinate Representations2005In: IEEE International Conference on Coordinated Multiple Views in Exploratory Visualization,2005, Los Alamitos, CA, USA: IEEE , 2005, p. 42-Conference paper (Refereed)
  • 18.
    Forsell, Camilla
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    An Introduction and Guide to Evaluation of Visualization Techniques Through User Studies2014In: Handbook of human centric visualization / [ed] Weidong Huang, New York: Springer, 2014, p. 285-313Chapter in book (Refereed)
  • 19.
    Forsell, Camilla
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Questionnaires for evaluation in information visualization2012In: BELIV '12 Proceedings of the 2012 BELIV Workshop: Beyond Time and Errors - Novel Evaluation Methods for Visualization, New York: ACM Press, 2012Conference paper (Refereed)
    Abstract [en]

    The position taken in this paper is that the availability of standardized questionnaires specifically developed for measuring users' perception of usability in evaluation studies in information visualization would provide the community with an excellent additional instrument. The need for such an instrument is evident for several important reasons. Pursuing the development, validation and use of questionnaires will add significantly to the evidence base necessary for the community to guide the production of high-quality visualization techniques, facilitate adoption by users, promote successful commercialization and guide future research tasks.

  • 20.
    Hassan, Kahin Akram
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Rönnberg, Niklas
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Forsell, Camilla
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Johansson, Jimmy
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Linköping University, Centre for Climate Science and Policy Research, CSPR.
    A Study on 2D and 3D Parallel Coordinates for Pattern Identification in Temporal Multivariate Data2019Conference paper (Refereed)
    Abstract [en]

    Parallel coordinates are commonly used for non-temporal multivariate data, but there is little support for their usability for displaying temporal multivariate data. In this paper, we introduce a study evaluating the usability of 2D and 3D parallel coordinates for pattern identification in temporal multivariate data. The results indicate that 3D parallel coordinates have higher usability, as measured with higher accuracy and faster response time as well as subjective ratings, compared to 2D.

  • 21.
    Hewitt, W. Terry
    et al.
    Manchester Visualization Centre University of Manchester.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Kwok, K. Yien
    Manchester Visualization Centre University of Manchester.
    Leaver, George
    Manchester Visualization Centre University of Manchester.
    Leng, Joanna
    Manchester Visualization Centre University of Manchester.
    Lever, Paul
    Manchester Visualization Centre University of Manchester.
    McDerby, Mary
    Manchester Visualization Centre University of Manchester.
    Perrin, James
    Manchester Visualization Centre University of Manchester.
    Riding, Mark
    Manchester Visualization Centre University of Manchester.
    Sadarjoen, I. Ari
    Manchester Visualization Centre University of Manchester.
    Schiebeck, Tobias
    Manchester Visualization Centre University of Manchester.
    Venters, Colin
    Manchester Visualization Centre University of Manchester.
    Visualization with AVS2005In: The Visualization Handbook / [ed] Charles D. Hansen, Chris R. Johnson, Oxford, UK: Elsevier , 2005, 1, p. 689-716Chapter in book (Other academic)
    Abstract [en]

    The Visualization Handbook provides an overview of the field of visualization by presenting the basic concepts, providing a snapshot of current visualization software systems, and examining research topics that are advancing the field. This text is intended for a broad audience, including not only the visualization expert seeking advanced methods to solve a particular problem, but also the novice looking for general background information on visualization topics. The largest collection of state-of-the-art visualization research yet gathered in a single volume, this book includes articles by a "who's who” of international scientific visualization researchers covering every aspect of the discipline, including: · Virtual environments for visualization · Basic visualization algorithms · Large-scale data visualization · Scalar data isosurface methods · Visualization software and frameworks · Scalar data volume rendering · Perceptual issues in visualization · Various application topics, including information visualization. * Edited by two of the best known people in the world on the subject; chapter authors are authoritative experts in their own fields; * Covers a wide range of topics, in 47 chapters, representing the state-of-the-art of scientific visualization.

  • 22.
    Johansson, Jimmy
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    A screen space quality method for data abstraction2008In: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, Vol. 27, no 3, p. 1039-1046Article in journal (Refereed)
    Abstract [en]

    The rendering of large data sets can result in cluttered displays and non-interactive update rates, leading to time consuming analyses. A straightforward solution is to reduce the number of items, thereby producing an abstraction of the data set. For the visual analysis to remain accurate, the graphical representation of the abstraction must preserve the significant features present in the original data. This paper presents a screen space quality method, based on distance transforms, that measures the visual quality of a data abstraction. This screen space measure is shown to better capture significant visual structures in data, compared with data space measures. The presented method is implemented on the GPU, allowing interactive creation of high quality graphical representations of multivariate data sets containing tens of thousands of items. © 2008 The Eurographics Association and Blackwell Publishing Ltd.

  • 23.
    Johansson, Jimmy
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Jern, Mikael
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    3-Dimensional Display for Clustered Multi-Relational Parallel Coordinates2005In: Proceedings of IEEE International Conference on Information Visualisation, IV05, 6-8 July, 2005, p. 188-193Conference paper (Other academic)
    Abstract [en]

    Analysing multivariate data is a difficult task. Extensive interaction with the data is often necessary and, hence, the analysis can be quite time consuming. In this paper, we introduce a method to allow the user to simultaneously examine the relationships of a single dimension with many others in the data. The single dimension can then be interactively changed to allow the user to quickly examine all possible combinations. This method is achieved by extending the standard parallel coordinate approach to a 3D clustered multi-relational parallel coordinate representation (CMRPC). To aid this method, we use a technique called relation spacing which is used to position the axes according to how 'interesting' the different relations are. We also propose a number of interaction techniques to further facilitate the analysis process.

  • 24.
    Johansson, Jimmy
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Forsell, Camilla
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    On the usability of three-dimensional display in parallel coordinates: Evaluating the efficiency of identifying two-dimensional relationships2014In: Information Visualization, ISSN 1473-8716, E-ISSN 1473-8724, Vol. 13, no 1, p. 29-41Article in journal (Refereed)
    Abstract [en]

    In recent years, several different attempts have been made to extend the well-known technique of parallel coordinates using a three-dimensional display. This article presents an evaluation that investigates the performance of the three-dimensional parallel coordinates technique and compares it with standard, two-dimensional parallel coordinates for analysis of two-dimensional relationships. Three-dimensional parallel coordinates, based on parallel planes instead of parallel axes, have been used for many years within the information visualization community for a variety of applications. Despite its quite common use, no formal evaluation detailing its usefulness for different tasks has been conducted. The evaluation presented in this article is the first step towards determining the usefulness of this type of three-dimensional parallel coordinates. The study compared three-dimensional parallel coordinates, using two different axis configurations commonly seen in the literature, with standard two-dimensional parallel coordinates for identification of two-dimensional relationships between variables in multivariate data. This type of task and the relationships to be judged are known to be well supported by two-dimensional parallel coordinates and multi-relational three-dimensional parallel coordinates. The results show that for identification of two-dimensional relationships, two-dimensional parallel coordinates are superior to the three-dimensional extensions, in terms of both response time and accuracy. Subjective opinions were also in favour of two-dimensional parallel coordinates. This study adds to the much-needed body of work examining the usability of three-dimensional representations in information visualization and for what tasks and data a proposed method is or is not appropriate.

  • 25.
    Johansson, Jimmy
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Forsell, Camilla
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Lind, Mats
    Uppsala University.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Perceiving Patterns in Parallel Coordinates: Determining Thresholds for Identification of Relationships2008In: Information Visualization, ISSN 1473-8716, E-ISSN 1473-8724, Vol. 7, no 2, p. 152-162Article in journal (Refereed)
    Abstract [en]

    This article presents a study that investigates the ability of humans to perceive relationships (patterns) in parallel coordinates, an ability that is crucial to the use of this popular visualization technique. It introduces a visual quality metric, acceptable distortions of patterns, which establishes the level of noise that may be present in data while allowing accurate identification of patterns. This metric was used to assess perceptual performance of standard 2D parallel coordinates and multi-relational 3D parallel coordinates in two experiments. In multi-relational 3D parallel coordinates the axes are placed on a circle with a focus axis in the centre, allowing a simultaneous analysis between the focus variable and all other variables. The experiments aimed to determine the maximum number of variables that can be, from a user's point of view, efficiently used in a multi-relational 3D parallel coordinates display and to present a first attempt to study users' ability to analyse noisy data in parallel coordinates. The results show that, in terms of the acceptable level of noise in data, a multi-relational 3D parallel coordinates visualization having 11 axes (variables) is as efficient as standard 2D parallel coordinates. Visualizing a larger number of variables would possibly require a greater amount of manipulation of the visualization and thus be less efficient.

  • 26.
    Johansson, Jimmy
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Lindgren, David
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ljung, Lennart
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Interactive Analysis of Time-Varying Systems Using Volume Graphics2004In: Proceedings of the 43rd IEEE Conference on Decision and Control, 2004, p. 5083-5087Conference paper (Refereed)
    Abstract [en]

    We show how 3-dimensional volume graphics can be used as a tool in system identification. Time-dependent dynamics often leave a significant residual with linear, time-invariant models. The structure of this residual is decisive for the subsequent modelling, and by using advanced visualization techniques, the modeller may gain a deeper insight into this structure than that which can be obtained from standard correlation analysis. We present a development platform that merges a rich variety of estimation programs with state of the art visualization techniques.

  • 27.
    Johansson, Jimmy
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Lindgren, David
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ljung, Lennart
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Interactive Visualization as a Tool for Analysing Time-Varying and Non-Linear Systems2005In: Proceedings of the 16th IFAC World Congress, 2005, p. 95-95Conference paper (Refereed)
    Abstract [en]

    This paper shows how 3-dimensional interactive visualization can be used as a tool in system identification. Non-linear or time-dependent dynamics often leave a significant residual with linear, time-invariant models. The structure of this residual is decisive for the subsequent modelling, and by using advanced visualization techniques, the modeller may gain a deeper insight into this structure than can be obtained by standard correlation analysis.

  • 28.
    Johansson, Jimmy
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ljung, Patric
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Depth Cues and Density in Temporal Parallel Coordinates2007In: EUROVIS'07 Proceedings of the 9th Joint Eurographics / IEEE VGTC Symposium on Visualization, Aire-la-Ville, Switzerland: Eurographics - European Association for Computer Graphics, 2007, p. 35-42Conference paper (Other academic)
    Abstract [en]

    This paper introduces Temporal Density Parallel Coordinates (TDPC) and Depth Cue Parallel Coordinates (DCPC) which extend the standard 2D parallel coordinates technique to capture time-varying dynamics. The proposed techniques can be used to analyse temporal positions of data items as well as temporal positions of changes occurring using 2D displays. To represent temporal changes, polygons (instead of traditional lines) are rendered in parallel coordinates. The results presented show that rendering polygons is superior at revealing large temporal changes. Both TDPC and DCPC have been efficiently implemented on the GPU allowing the visualization of thousands of data items over thousands of time steps at interactive frame rates.

  • 29.
    Johansson, Jimmy
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ljung, Patric
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Depth Cues and Density in Temporal Parallel Coordinates2007In: Proceedings of Eurographics/IEEE VGTC Symposium on Visualization, Norrköping, Sweden, Aire-la-Ville, Switzerland: Eurographics Association , 2007, p. 35-42Conference paper (Other academic)
    Abstract [en]

    This paper introduces Temporal Density Parallel Coordinates (TDPC) and Depth Cue Parallel Coordinates (DCPC) which extend the standard 2D parallel coordinates technique to capture time-varying dynamics. The proposed techniques can be used to analyse temporal positions of data items as well as temporal positions of changes occurring using 2D displays. To represent temporal changes, polygons (instead of traditional lines) are rendered in parallel coordinates. The results presented show that rendering polygons is superior at revealing large temporal changes. Both TDPC and DCPC have been efficiently implemented on the GPU allowing the visualization of thousands of data items over thousands of time steps at interactive frame rates.

  • 30.
    Johansson, Jimmy
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ljung, Patric
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Jern, Mikael
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Revealing Structure in Visualizations of Dense 2D and 3D Parallel Coordinates2006In: Information Visualization, ISSN 1473-8716, Vol. 5, no 2, p. 125-136Article in journal (Refereed)
    Abstract [en]

    Parallel coordinates is a well-known technique used for visualization of multivariate data. When the size of the data sets increases the parallel coordinates display results in an image far too cluttered to perceive any structure. We tackle this problem by constructing high-precision textures to represent the data. By using transfer functions that operate on the high-precision textures, it is possible to highlight different aspects of the entire data set or clusters of the data. Our methods are implemented in both standard 2D parallel coordinates and 3D multi-relational parallel coordinates. Furthermore, when visualizing a larger number of clusters, a technique called 'feature animation' may be used as guidance by presenting various cluster statistics. A case study is also performed to illustrate the analysis process when analysing large multivariate data sets using our proposed techniques.

  • 31.
    Johansson, Jimmy
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ljung, Patric
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Jern, Mikael
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Revealing Structure within Clustered Parallel Coordinates Displays2005In: Proceedings of IEEE Symposium on Information Visualization, 23-25 Oct., 2005, p. 125-132Conference paper (Other academic)
    Abstract [en]

    In order to gain insight into multivariate data, complex structures must be analysed and understood. Parallel coordinates is an excellent tool for visualizing this type of data but has its limitations. This paper deals with one of its main limitations - how to visualize a large number of data items without hiding the inherent structure they constitute. We solve this problem by constructing clusters and using high precision textures to represent them. We also use transfer functions that operate on the high precision textures in order to highlight different aspects of the cluster characteristics. Providing predefined transfer functions as well as the support to draw customized transfer functions makes it possible to extract different aspects of the data. We also show how feature animation can be used as guidance when simultaneously analysing several clusters. This technique makes it possible to visually represent statistical information about clusters and thus guides the user, making the analysis process more efficient.

  • 32.
    Johansson, Jimmy
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Ljung, Patric
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Lindgren, David
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Linköping University, Center for Medical Image Science and Visualization (CMIV).
    Interactive Visualization Approaches to the Analysis of System Identification Data2004In: Information Visualization, 2004. INFOVIS 2004. IEEE Symposium on, 2004Conference paper (Refereed)
    Abstract [en]

    We propose an interactive visualization approach to finding a mathematical model for a real world process, commonly known in the field of control theory as system identification. The use of interactive visualization techniques provides the modeller with instant visual feedback which facilitates the model validation process. When working interactively with such large data sets, as are common in system identification, methods to handle this data efficiently are required. We are developing approaches based on data streaming to´meet this need.

  • 33.
    Klashed, Staffan
    et al.
    SCISS AB, Stockholm, Sweden.
    Hemingsson, Per
    SCISS AB, Stockholm, Sweden.
    Emmart, Carter
    American Museum of Natural History, New York, USA.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Uniview - Visualizing the Universe2010In: Eurographics 2010 - Areas Papers, Norrköping, Sweden: Eurographics Association , 2010Conference paper (Refereed)
    Abstract [en]

    This paper describes the development of the software system, Uniview, the motivation behind some of the most prominent features of the system and the strengths and challenges of running a development project in such close collaboration with the users. Uniview is a sophisticated system for the visual display and exploration of the enormous and complex data which the human race has gathered about the universe. This beautiful, fascinating data, with it’s sheer size both in terms of data elements and the distances between the objects in the known universe, presents challenges to the developer at all levels: from basic rendering through representation and to data managment.

  • 34.
    Kocak, Umut
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Lundin Palmerius, Karljohan
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    An Error Analysis Model for Adaptive Deformation Simulation2012Conference paper (Other academic)
    Abstract [en]

    With the widespread use of deformation simulations in medical applications, the realism of the force feedback has become an important issue. In order to reach real-time performance with sufficient realism the approach of adaptivity, solution of different parts of the system with different resolutions and refresh rates, has been commonly deployed. The change in accuracy resulting from the use of adaptivity, however, has been been paid scant attention in the deformation simulation field. Presentation of error metrics is rare, while more focus is given to the real-time stability. We propose an abstract pipeline to perform error analysis for different types of deformation techniques which can consider different simulation parameters. A case study is also performed using the pipeline, and the various uses of the error estimation are discussed.

  • 35.
    Kocak, Umut
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Lundin Palmerius, Karljohan
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Anisotropic Virtual Coupling with Energy-Based Deflection for Palpating Inhomogeneous Compliant Objects2013In: Proceedings of the IEEE World Haptics Conference, IEEE , 2013, p. 115-120Conference paper (Refereed)
    Abstract [en]

    Virtual coupling, a spring-damper system between the haptic probe and its virtual representation, the proxy, is one of the most common approaches for haptic rendering. We have extended the virtual coupling by updating the spring stiffness, sometimes used to simulate compliance of a material, depending on the direction between the proxy and the probe. This anisotropic variation of the stiffness is used in exploring inhomogeneities beneath the surface allowing detection of rigid structures even when they are obscured by another structure beneath the surface. In addition, we also compensate for the energy variation of the spring to maintain passivity and increase realism. User studies were performed to survey the success rate in the detection of obscured rigid bodies beneath the surface with the modified virtual coupling algorithm and the improvement of shape perception for sub-surface objects with the additional energy compensation term providing gradient information. We also discuss potential benefits of the proposed methods as basic extensions to well-known haptic rendering algorithms which are both simpler and yield improved performance over traditional deformation simulationtechniques.

  • 36.
    Kocak, Umut
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Lundin Palmerius, Karljohan
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    High Resolution Enhancement in Deformation via Anisotropic Virtual Coupling2013Manuscript (preprint) (Other academic)
    Abstract [en]

    Achieving sufficient realism in deformation simulations requires consideration  of complex physical properties. The computational burden of modelling these properties requires the use of low resolution meshes to attain real time interactive performance. Medical data such as MR and CT, on the other hand, have much higher resolutions than can be practically used in deformation simulations. This results in significant amount of information loss, degenerating the ability to perceive variations in the data, especially inhomogeneities. In this paper, we address this issue by employing surfacerendering algorithms which can provide high resolution information from beneath the surface. An experiment was performed in a scenario simulating inhomogeneities of bone structure under the skin. Results have shown significant improvement for detecting inhomogeneities within deformable data while palpating the surface.

  • 37.
    Kocak, Umut
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Lundin Palmerius, Karljohan
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Forsell, Camilla
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Analysis of the JND of Stiness in Three Modesof Comparison2011In: HAID'11 Proceedings of the 6th international conference on Haptic and audio interaction design / [ed] Cooper, E., Brewster, S., Ogawa, H., Kryssanov, V.K., Springer Berlin/Heidelberg, 2011, p. 22-31Conference paper (Other academic)
    Abstract [en]

    Understanding and explaining perception of touch is a non-trivial task. Even seemingly trivial differences in exploration may potentially have a significant impact on perception and levels of discrimination. In this study, we explore different aspects of contact related to stiffness perception and their effects on the just noticeable difference (JND) of stiffness are surveyed. An experiment has been performed on non-deformable, compliant objects in a virtual environment with three different types of contact: Discontinuous pressure, continuous pressure and continuous lateral motion. The result shows a significantly better discrimination performance in the case of continuous pressure (a special case of nonlinearity), which can be explained by the concept of haptic memory. Moreover, it is found that the perception is worse for the changes that occur along the lateral axis than the normal axis.

  • 38.
    Kocak, Umut
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Palmerius, Karljohan
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Dynamic Deformation Using Adaptable, Linked Asynchronous FEM Regions2009In: Spring Conference on Computer Graphics / [ed] Helwig Hauser and Stephen N. Spencer, New York: ACM , 2009, p. 197-204Conference paper (Refereed)
    Abstract [en]

    In order to simulate both physically and visually realistic soft tissue deformations, the Finite Element Method (FEM) is the mostpopular choice in the literature. However it is non-trivial to modelcomplex behaviour of soft tissue with sufficient refresh rates, especiallyfor haptic force feedback which requires an update rate ofthe order of 1 kHz. In this study the use of asynchronous regions isproposed to speed up the solution of FEM equations in real-time. Inthis way it is possible to solve the local neighborhood of the contactwith high refresh rates, while evaluating the more distant regions atlower frequencies, saving computational power to model complexbehaviour within the contact area. Solution of the different regionsusing different methods is also possible. To attain maximum efficiencythe size of the regions can be changed, in real-time, in responseto the size of the deformation.

  • 39.
    Kocak, Umut
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Palmerius, Karljohan
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Forsell, Camilla
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, The Institute of Technology.
    The Effect of the Stiffness Gradient on the Just Noticeable Difference between Surface Regions2012In: Haptics: Perception, Devices, Mobility, and Communication: International Conference, EuroHaptics 2012, Tampere, Finland, June 13-15, 2012. Proceedings, Part I / [ed] Poika Isokoski, Jukka Springare, Springer Berlin/Heidelberg, 2012, p. 282-292Chapter in book (Refereed)
    Abstract [en]

    This book and its companion volume, LNCS 7282 and 7283, constitute the refereed proceedings of the 8th International Conference, EuroHaptics 2012, held in Tampere, Finland, in June 2012. The 99 papers (56 full papers, 32 short papers, and 11 demo papers) presented were carefully reviewed and selected from 153 submissions. Part I contains the full papers whereas Part II contains the short papers and the demo papers.

  • 40.
    Lange, Marcus
    et al.
    Linköping University, Department of Science and Technology.
    Bourgois, Marc
    INO Eurocontrol Experimental Centre.
    Duong, Vu
    INO Eurocontrol Experimental Centre.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Interactive and Immersive 3D Visualization for ATC2005In: Eurocontrol Innovative Research Workshop,2005, Bruxelles, BE: Eurocontrol , 2005, p. 27-42Conference paper (Other academic)
  • 41.
    Lange, Marcus
    et al.
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Dang, Nguyen Thong
    Linköping University, The Institute of Technology. Linköping University, Department of Science and Technology.
    Cooper, Matthew D.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Interactive Resolution of Conflicts in a 3D Stereoscopic Environment for Air Traffic Control2006In: IEEE International Conference on Computer Sciences - RIVF06,2006, IEEE Computer Society , 2006, p. 32-Conference paper (Refereed)
  • 42.
    Lind, Mats
    et al.
    Department of Information Science, Uppsala University, Sweden.
    Johansson, Jimmy
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Many-to-Many Relational Parallel Coordinates Displays2009In: Information Visualisation: IV 2009 / [ed] Ebad Banissi et al., Los Alamitos, CA, USA: IEEE Computer Society, 2009, p. 25-31Conference paper (Refereed)
    Abstract [en]

    An interesting property of the commonly used parallel coordinates display is the distinct overall pattern formed by the totality of lines between adjacent axes. These patterns have a direct correspondence to the type of relationship existing between the variables mapped onto the axes in question as well as a salient visual appearance. Parallel coordinates displays can therefore be used to visually investigate relationships between variables as well as investigating individual objects/lines. The problem with this approach is that, whereas each object is mapped in its entirety in a standard parallel coordinates display, only a small subset of the interrelations between variables is shown as the number of variables increase. To show all possible relations between variables multiple parallel coordinates displays are needed. In turn this means that each variable is duplicated several times, once per extra parallel coordinates display. To a viewer this increases the visual complexity and most probably the mental load. To aid users we have devised a new configuration of the axes in multiple parallel coordinates displays. Through an experiment we have also started to investigate the usability of this new configuration and the results are promising.

  • 43.
    Lindgren, David
    et al.
    Linköping University, Department of Electrical Engineering, Automatic Control. Linköping University, The Institute of Technology.
    Johansson, Jimmy
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ljung, Patric
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Interactive Visualization Approaches to the Analysis of System Identification Data2004In: Proceedings of the 10th IEEE Symposium on Information Visualization, 2004, p. 23-Conference paper (Refereed)
    Abstract [en]

    We propose an interactive visualization approach to finding a mathematical model for a real world process, commonly known in the field of control theory as system identification. The use of interactive visualization techniques provides the modeller with instant visual feedback which facilitates the model validation process. When working interactively with such large data sets, as are common in system identification, methods to handle this data efficiently are required. We are developing approaches based on data streaming to meet this need.

  • 44.
    Lundin (Palmerius), Karljohan
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Persson, Anders
    Linköping University, Faculty of Health Sciences. Linköping University, Department of Medicine and Care, Medical Radiology. Östergötlands Läns Landsting, Centre for Medical Imaging, Department of Radiology UHL. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Evestedt, Daniel
    SenseGraphics AB.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Enabling design and interactive selection of haptic modes2007In: Virtual Reality, ISSN 1359-4338, E-ISSN 1434-9957Article in journal (Refereed)
    Abstract [en]

    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.

  • 45.
    Lundin Palmerius, Karljohan
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Flow Field Visualization Using Vector Field Perpendicular Surfaces2009In: Proceedings of Spring Conference on Computer Graphics, Bratislava: Comenius University , 2009, p. 27-34Conference paper (Refereed)
    Abstract [en]

    This paper introduces Vector Field Perpendicular Surfaces as a means to represent vector data with special focus on variations across the vectors in the field. These surfaces are a perpendicular analogue to streamlines, with the vector data always being parallel to the normals of the surface. In this way the orientation of the data is conveyed to the viewer, while providing a continuous representation across the vectors of the field. This paper describes the properties of such surfaces including an issue with helicity density in the vector data, an approach to generating them, several stop conditions and special means to handle also fields with non-zero helicity density.

  • 46.
    Lundin Palmerius, Karljohan
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Haptic Rendering of Dynamic Volumetric Data2008In: IEEE Transactions on Visualization and Computer Graphics, ISSN 1077-2626, E-ISSN 1941-0506, Vol. 14, no 2, p. 263-276Article in journal (Refereed)
    Abstract [en]

    With current methods for volume haptics in scientific visualization, features in time-varying data can freely move straight through the haptic probe without generating any haptic feedback-the algorithms are simply not designed to handle variation with time but consider only the instantaneous configuration when the haptic feedback is calculated. This article introduces haptic rendering of dynamic volumetric data to provide a means for haptic exploration of dynamic behavior in volumetric data. We show how haptic feedback can be produced that is consistent with volumetric data moving within the virtual environment and with data that, in itself, evolves over time. Haptic interaction with time-varying data is demonstrated by allowing palpation of a computerized tomography sequence of a beating human heart.

  • 47.
    Lundin (Palmerius), Karljohan
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    The Orthogonal Constraints Problem with the Constraint Approach to Proxy-based Volume Haptics and a Solution2005In: SIGRAD 2005, Lund, Sweden, 2005, p. 45-49Conference paper (Refereed)
    Abstract [en]

    Recently the constraint approach to proxy-based volume haptics was introduced which provided a stable and effective means of conveying information about volumetric data through a haptic instrument. In this paper we present a proof that the approach is incapable of handling nonorthogonal constraints and discuss the implications of this restriction in detail. We also describe how full utilization of haptics applications in which multiple properties are used to enhance the understanding of complex data requires the use of non-orthogonal constraints. We then show how proxybased volume haptics can be modified to allow for general constraints through the introduction of haptic primitives used to model the constraints. By balancing the forces exerted by the primitives on the proxy continuously, nonorthogonal constraints can be handled.

  • 48.
    Lundin (Palmerius), Karljohan
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Lundström, Claes
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology. Linköping University, Center for Medical Image Science and Visualization, CMIV.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Enabling Haptic Interaction with Volumetric MRI Data Through Knowledge-based Tissue Separation2006In: Proceedings of Volume Graphics, 2006, p. 75-78Conference paper (Refereed)
    Abstract [en]

    Direct volume haptics can provide both guidance and extra information during exploration of volumetric data. In this paper we present a novel approach to volume haptics enabling haptic exploration of tissue shape, borders and material properties in data despite low contrast and low signal to noise ratio, as is common in medical MRI data or low dose CT data. The method uses filtering based on implicit knowledge and addresses the problem of overlapping scalar ranges through the introduction of fuzzy classification and corresponding transfer functions for material properties as well as classification-based distance masking for haptic force direction.

  • 49.
    Lundin (Palmerius), Karljohan
    et al.
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Sillén, Mattias
    SAAB AB.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Ynnerman, Anders
    Linköping University, Department of Science and Technology, Visual Information Technology and Applications (VITA). Linköping University, The Institute of Technology.
    Haptic Visualization of Computational Fluid Dynamics Data Using Reactive Forces2005In: International Conference on Visualization and Data Analysis, San Jose, USA, 2005, p. 95-102Conference paper (Refereed)
    Abstract [en]

    Datasets from Computational Fluid Dynamics (CFD) can be post-processed and visualized to aid understanding of the flow phenomena present. Visualization of CFD data, however, often suffers from problems such as occlusion and cluttering when methods such as glyphing and volume rendering are applied. In this paper we present a case study where new modes for haptic interaction are used to enhance the exploration of CFD data. A VR environment with interactive graphics and an integrated graphical user interface has been implemented. In contrast to previous work on haptic interaction with CFD data we employ a 'reactive' haptic scheme as opposed to direct force maping. The reactive approach not only generates more stable feedback but also provides clearer and more intuitive cues about the underlying data. Two haptic modes are used to enhance the understanding of different features in the flow data: One presents the orientation of the data and also guides the user to follow the stream as it flows around the aircraft fuselage. The other provides a haptic representation of vortex data. This mode enables the user to perceive and so follow tendencies of vorticity and vortices.

  • 50.
    Muthumanickam, Prithiviraj
    et al.
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Vrotsou, Katerina
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Vitoria, Aida
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Johansson, Jimmy
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering. Linköping University, Centre for Climate Science and Policy Research, CSPR.
    Cooper, Matthew
    Linköping University, Department of Science and Technology, Media and Information Technology. Linköping University, Faculty of Science & Engineering.
    Identification of Temporally Varying Areas of Interest in Long-Duration Eye-Tracking Data Sets2018In: IEEE Transactions on Visualization and Computer Graphics, ISSN 1077-2626, E-ISSN 1941-0506Article in journal (Refereed)
    Abstract [en]

    Eye-tracking has become an invaluable tool for the analysis of working practices in many technological fields of activity. Typically studies focus on short tasks and use static expected areas of interest (AoI) in the display to explore subjects’ behaviour, making the analyst’s task quite straightforward. In long-duration studies, where the observations may last several hours over a complete work session, the AoIs may change over time in response to altering workload, emergencies or other variables making the analysis more difficult. This work puts forward a novel method to automatically identify spatial AoIs changing over time through a combination of clustering and cluster merging in the temporal domain. A visual analysis system based on the proposed methods is also presented. Finally, we illustrate our approach within the domain of air traffic control, a complex task sensitive to prevailing conditions over long durations, though it is applicable to other domains such as monitoring of complex systems. 

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