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  • 201. Bestill onlineKjøp publikasjonen >>
    Domova, Veronika
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. ABB Corporate Research, Västerås.
    Designing visualization and interaction for industrial control rooms of the future2020Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    During the last decades, the industry has been undergoing extensive digitization leading to complex ensembles of humans, machines, autonomous agents, and sensors. With this new setup comes the challenge of how to appropriately support work-practices of industrial operators who now need to monitor and control complex industrial processes through remote interfaces. Information overflow and restrictive interfaces are two significant problems that operators face in their daily routines. In this PhD, I explore approaches to visualization and interaction that would reduce industrial operators' information load and enable them to perform their duties in an efficient, reliable, and safe manner. Industrial users and industrial settings are the starting points of my research.

    In this thesis, I describe multiple examples of custom-tailored data visualizations that reduce the operator's visual load by consolidating large amounts of data into compact overview displays with often nontrivial data presentation. With respect to interaction, I propose several tangible and tactile interfaces, as well as concepts for natural interaction, that let the user freely interact with the control station and the information it depicts. Finally, I propose several concepts of adaptive systems that adjust to the operator's context to ensure their high situational awareness and convenience of interaction.

    Even though this thesis is primarily intended for the community of interaction designers, I expect it to be of interest to a broader audience due to its relation to the user experience field. To a certain extent, everyone can resonate with the user's problems because, in our everyday life, we all are users of some technology and services. Furthermore, for a lay reader, this work can be seen as a comprehensive introduction to how the industry works and what role the human plays there.

    Delarbeid
    1. Visualization for Quality Healthcare: Patient Flow Exploration
    Åpne denne publikasjonen i ny fane eller vindu >>Visualization for Quality Healthcare: Patient Flow Exploration
    2019 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    The health and medical institutes and hospitalsare facing several challenges in the short and long term, i.e.demographic changes, demands on improving quality, limitedresources and cost requirements. To cope with these challenges,the health care sector needs to become more efficient, whilemaintaining and improving the quality of care. Efficient andtransparent information flow across the whole system plays a keyrole even in this context. Being able to analyze the patient flowsas the first step will provide the possibility to more efficientlymanage medical resources and better serve incoming patients. Inthis work, we have developed a web-based portal for interactiveanalysis of patient flow data to assist hospital authorities toimprove and optimize the time and quality of the providedservices. The developed tool facilitates short and long termoptimization of resource allocation by analyzing the past, as wellas current, patient flows, identifying bottlenecks and exploringthe reasons for the occurred waiting times.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-165581 (URN)
    Konferanse
    IEEE Big Data
    Tilgjengelig fra: 2020-05-06 Laget: 2020-05-06 Sist oppdatert: 2020-05-19
    2. Feel the Water: Expressing Physicality of District Heating Processes in Functional Overview Displays
    Åpne denne publikasjonen i ny fane eller vindu >>Feel the Water: Expressing Physicality of District Heating Processes in Functional Overview Displays
    2019 (engelsk)Inngår i: PROCEEDINGS OF THE 2019 ACM INTERNATIONAL CONFERENCE ON INTERACTIVE SURFACES AND SPACES (ISS 19), ASSOC COMPUTING MACHINERY , 2019, s. 229-240Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    This paper describes an explorative design study conducted in the scope of a collaborative research project in the district heating domain. In the scope of the project, we have arranged extensive field studies at two power plants to understand the workflows, problems, and needs of industrial operators. We relied on the gained knowledge to design and develop novel visual interfaces that would communicate the overall status of the district heating system at-a-glance. We aimed at exploring potential directions and alternatives beyond conventional industrial interfaces. One particular aspect of our research was related to how the physicality of the underlying industrial processes can be expressed by purely visual means. The paper introduces three high-fidelity prototypes demonstrating the novel visualizations developed. The paper explains the design choices made, namely the relation between the selected visual encodings to the requirements of the industrial operators tasks. Preliminary evaluation indicates industrial operators interest in the designed solutions. Future work will incorporate an extensive qualitative evaluation on site.

    sted, utgiver, år, opplag, sider
    ASSOC COMPUTING MACHINERY, 2019
    Emneord
    Data visualization; Process control; District heating; Industrial operator; Industrial interface; User-centered design
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-165361 (URN)10.1145/3343055.3359708 (DOI)000523231300022 ()978-1-4503-6891-9 (ISBN)
    Konferanse
    14th ACM International Conference on Interactive Surfaces and Spaces (ISS)
    Merknad

    Funding Agencies|strategic innovation program PIIA2; Wallenberg AI, Autonomous Systems and Software Program (WASP)3 - Knut and Alice Wallenberg Foundation

    Tilgjengelig fra: 2020-04-27 Laget: 2020-04-27 Sist oppdatert: 2020-05-10
    3. Towards Effective Industrial Robot Fleet Visualization for Remote Service Applications
    Åpne denne publikasjonen i ny fane eller vindu >>Towards Effective Industrial Robot Fleet Visualization for Remote Service Applications
    2017 (engelsk)Inngår i: 2017 IEEE 26th International Conference on Enabling Technologies: Infrastructure for Collaborative Enterprises (WETICE) / [ed] Sumitra M. Reddy, Wojciech Cellary, and Mariagrazia Fugini, Institute of Electrical and Electronics Engineers (IEEE), 2017, s. 185-190Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    In recent years, advances in sensors, Internet and communication technologies opened many promising opportunities for remote services of industrial robots. With remote service applications, potential problems in robot systems can be detected before they happen, and prevented pro-actively avoiding costly production shut-downs. However, to be able to effectively perform remote service operations, remote support engineers need to analyse vast amounts of information. For a remote support engineer to be able to manage such amount of data, effective data visualization is crucial. Based on field studies and collected needs of support engineers working with industrial robots, we have designed and developed a prototype, i.e. one possible solution of an effective industrial fleet visualization, applied on the overheated robots use case. The initial validation of the prototype showed the benefits of such visual data presentation, as well as future directions.

    sted, utgiver, år, opplag, sider
    Institute of Electrical and Electronics Engineers (IEEE), 2017
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-152708 (URN)10.1109/WETICE.2017.40 (DOI)9781538617595 (ISBN)9781538617601 (ISBN)
    Konferanse
    The 26th International Conference on Enabling Technologies: Infrastructure for Collaborative Enterprises (WETICE), 21-23 June 2017, Poznan, Poland
    Tilgjengelig fra: 2018-11-15 Laget: 2018-11-15 Sist oppdatert: 2020-05-10bibliografisk kontrollert
    4. Re-Introducing Physical User Interfaces into Industrial Control Rooms
    Åpne denne publikasjonen i ny fane eller vindu >>Re-Introducing Physical User Interfaces into Industrial Control Rooms
    Vise andre…
    2017 (engelsk)Inngår i: Proceedings of the European Conference on Cognitive Ergonomics 2017, New York: ACM Digital Library, 2017, s. 162-168Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Within industrial control rooms the trend has been to move away from physical towards digital interfaces. However, operators working in these control rooms have expressed feeling a loss of connection to the production process and machinery they are controlling. As such we present two prototypes Haptic Mouse and Shift Report Tool which were used to explore the re-introduction of physical user interfaces into industrial control rooms.

    sted, utgiver, år, opplag, sider
    New York: ACM Digital Library, 2017
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-152709 (URN)10.1145/3121283.3121295 (DOI)9781450352567 (ISBN)
    Konferanse
    The European Conference on Cognitive Ergonomics, ECCE 2017, Umeå, Sweden, September 19-22, 2017
    Tilgjengelig fra: 2018-11-15 Laget: 2018-11-15 Sist oppdatert: 2020-05-10bibliografisk kontrollert
    5. Towards intelligent alarm management in the Age of IIoT
    Åpne denne publikasjonen i ny fane eller vindu >>Towards intelligent alarm management in the Age of IIoT
    2017 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    In recent years, IIoT continues to gain tractionintroducing promising opportunities to build powerful systemsand applications with new benefits to industry. However, as theindustrial systems become more complex, the number of alarmcalls in plants has exploded to a very large number. Having toomany alarms to handle hinders operators from taking the rightdecisions at the right time which potentially can lead to safety,reliability, privacy, and security issues. The work presentedin this paper is aimed at improving the safety of industrialoperations by better managing alarms and also increasing thereliability of the industrial operation by ensuring the processesare reliable. A main outcome of the project is a set of alarmdata mining algorithms and a high-fidelity prototype of a userinterface for reviewing and analyzing the mined alarm data.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-165578 (URN)
    Konferanse
    Global Internet of Things Summit
    Tilgjengelig fra: 2020-05-06 Laget: 2020-05-06 Sist oppdatert: 2020-05-10
    6. Supporting Maritime Remote Experts Working Over Distance
    Åpne denne publikasjonen i ny fane eller vindu >>Supporting Maritime Remote Experts Working Over Distance
    2016 (engelsk)Inngår i: Supporting Maritime Remote Experts Working Over Distance, 2016Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Within the maritime domain there is a shift taking placetowards how troubleshooting (i.e. understanding andxing equipment issues) is being oered to maritimecustomers. Instead of travelling to ships around the world,service support engineers now remotely connect andaccess data from equipment sensors on-board. With thisgame-changing approach to xing equipment issues comesthe need to eectively support this change inwork-practice since engineers now need to solve complexproblems from an onshore location. Based on ndingsfrom eld studies, we present a prototype as a rst-steptowards addressing some of the key needs of theseengineers which include improving situation awareness forenhanced remote troubleshooting, integrating all relevantinformation for easier searching, and faster access torelevant personnel for help. The prototype was validatedwith domain specialists, and based on the ndings a set ofdesign recommendations is also presented.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-165577 (URN)
    Konferanse
    NordiCHI
    Tilgjengelig fra: 2020-05-06 Laget: 2020-05-06 Sist oppdatert: 2020-05-15
    7. Untethered Workspaces: A Zones Concept Towards Supporting Operator Movements In Control Rooms
    Åpne denne publikasjonen i ny fane eller vindu >>Untethered Workspaces: A Zones Concept Towards Supporting Operator Movements In Control Rooms
    2016 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    Within industrial domains there is a need for control room operators to be in constant contact with the different processes they are responsible for controlling. With this responsibility comes the need to constantly be near their workstations in order to monitor, diagnose and quickly troubleshoot issues presented. These workstations, however, restrict operators in control rooms from moving freely within the control room itself, such as between their own and their colleague’s workstations since they cannot interact with the system from a distance. These systems also restrict those operators who need to continuously enter the control room from the plant/factory floor since interacting with process graphics requires them to remove all of their specialized equipment every time (e.g. large bulky safety gloves). We therefore present a concept for control room operators that supports their untethering from dedicated workstations, providing them with the ability to interact in a more flexible way.

    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-165562 (URN)
    Konferanse
    CHI
    Tilgjengelig fra: 2020-05-06 Laget: 2020-05-06 Sist oppdatert: 2020-05-10
    Fulltekst (pdf)
    fulltext
    Download (png)
    presentationsbild
  • 202.
    Domova, Veronika
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Untethered Workspaces: A Zones Concept Towards Supporting Operator Movements In Control Rooms2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Within industrial domains there is a need for control room operators to be in constant contact with the different processes they are responsible for controlling. With this responsibility comes the need to constantly be near their workstations in order to monitor, diagnose and quickly troubleshoot issues presented. These workstations, however, restrict operators in control rooms from moving freely within the control room itself, such as between their own and their colleague’s workstations since they cannot interact with the system from a distance. These systems also restrict those operators who need to continuously enter the control room from the plant/factory floor since interacting with process graphics requires them to remove all of their specialized equipment every time (e.g. large bulky safety gloves). We therefore present a concept for control room operators that supports their untethering from dedicated workstations, providing them with the ability to interact in a more flexible way.

  • 203.
    Domova, Veronika
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. ABB Corp Res, Sweden.
    Munoz, Alvaro Aranda
    RISE, Sweden.
    Vaara, Elsa
    RISE, Sweden.
    Edoff, Petra
    RISE, Sweden.
    Feel the Water: Expressing Physicality of District Heating Processes in Functional Overview Displays2019Inngår i: PROCEEDINGS OF THE 2019 ACM INTERNATIONAL CONFERENCE ON INTERACTIVE SURFACES AND SPACES (ISS 19), ASSOC COMPUTING MACHINERY , 2019, s. 229-240Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper describes an explorative design study conducted in the scope of a collaborative research project in the district heating domain. In the scope of the project, we have arranged extensive field studies at two power plants to understand the workflows, problems, and needs of industrial operators. We relied on the gained knowledge to design and develop novel visual interfaces that would communicate the overall status of the district heating system at-a-glance. We aimed at exploring potential directions and alternatives beyond conventional industrial interfaces. One particular aspect of our research was related to how the physicality of the underlying industrial processes can be expressed by purely visual means. The paper introduces three high-fidelity prototypes demonstrating the novel visualizations developed. The paper explains the design choices made, namely the relation between the selected visual encodings to the requirements of the industrial operators tasks. Preliminary evaluation indicates industrial operators interest in the designed solutions. Future work will incorporate an extensive qualitative evaluation on site.

  • 204.
    Doyle, Scott
    et al.
    Rutgers University, Dept. of Biomedical Engineering Piscataway, NJ, USA.
    Monaco, James
    Rutgers University, Dept. of Biomedical Engineering Piscataway, NJ, USA.
    Madabhushi, Anant
    Rutgers University, Dept. of Biomedical Engineering Piscataway, NJ, USA.
    Lindholm, Stefan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan. Siemens Corporate Research,Princeton, NJ, USA.
    Ljung, Patric
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. Siemens Corporate Research,Princeton, NJ, USA.
    Ladic, Lance
    Siemens Corporate Research,Princeton, NJ, USA.
    Tomaszewski, John
    University of Pennsylvania,Dept. of Surgical Pathology Philadelphia, PA, USA.
    Feldman, Michael
    University of Pennsylvania,Dept. of Surgical Pathology Philadelphia, PA, USA.
    Evaluation of effects of JPEG2000 compression on a computer-aided detection system for prostate cancer on digitized histopathology2010Inngår i: Biomedical Imaging: From Nano to Macro, 2010 IEEE International Symposium on, 2010, s. 1313-1316Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A single digital pathology image can occupy over 10 gigabytes of hard disk space, rendering it difficult to store, analyze, and transmit. Though image compression provides a means of reducing the storage requirement, its effects on computer-aided diagnosis (CAD) and pathologist performance are not yet clear. In this work we assess the impact of compression on the ability of a CAD system to detect carcinoma of the prostate (CaP) on histological sections. The CAD algorithm proceeds as follows: Glands in the tissue are segmented using a region-growing algorithm, and the size of each gland is extracted. A Markov prior (specifically, a probabilistic pairwise Markov model) is employed to encourage nearby glands to share the same class (i.e. cancerous or non-cancerous). Finally, cancerous glands are aggregated into continuous regions using a distancehull algorithm. We trained the CAD system on 28 images of wholemount histology (WMH) and evaluated performance on 12 images compressed at 14 different compression ratios (a total of 168 experiments) using JPEG2000. Algorithm performance (measured using the under the receiver operating characteristic curves) remains relatively constant for compression ratios up to1 :256, beyond which performance degrades precipitously. For completeness we also have an expert pathologist view a randomly-selected set of compressed images from one of the whole mount studies and assign a confidence measure as to their diagnostic fidelity. Pathologist confidence declined with increasing compression ratio as the information necessary to diagnose the sample was lost, dropping from 100% confidence at ratio 1:64 to 0% at ratio 1:8192.

  • 205.
    Durmén Blunt, Tina
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Personalized visualization of blog statistics2013Independent thesis Basic level (university diploma), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report documents the research, implementation and result for a master thesis in Media Technology and Engineering at Linkoping University. The aim of the project was to develop a personalized visualization application of blog statistics to be implemented on a web based community for blog authors. The purpose of the application is to provide the users with a tool to explore statistics connected to their own blog. Based on a literature study in usability and information visualization the application design was developed and implemented. The implementation resulted in a JavaScript based application, BlogVis, that allows the users to compare their own blog statistics with others, as well as compare periods of time in the statistic history of the blog.

    Fulltekst (pdf)
    fulltext
  • 206.
    Dwyer, Tim
    et al.
    Monash University, Australia.
    Elmqvist, Niklas
    University of Maryland, MD 20742 USA.
    Fisher, Brian
    Simon Fraser University, Canada.
    Franconeri, Steve
    Northwestern University, IL 60208 USA.
    Hotz, Ingrid
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Mike Kirby, Robert M.
    University of Utah, UT 84112 USA.
    Liu, Shixia
    Tsinghua University, Peoples R China.
    Schreck, Tobias
    Graz University of Technology, Austria.
    Yuan, Xiaoru
    Peking University, Peoples R China.
    Message from the VIS Paper Chairs and Guest Editors Preface2018Inngår i: IEEE Transactions on Visualization and Computer Graphics, ISSN 1077-2626, E-ISSN 1941-0506, Vol. 24, nr 1, s. XI-XVArtikkel i tidsskrift (Annet vitenskapelig)
  • 207.
    Dynewall, Tove
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Johansson, Ida
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Att interagera med 3D-objekt i en förstärkt verklighet2018Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    Augmented reality (AR), eller förstärkt verklighet, är variation av virtuell verklighet. AR är ett relativt nytt medium och har på senare tiden blivit allt vanligare i applikationer för mobilen. Då AR är så starkt kopplat till den verkliga världen har det blivit allt vanligare att integrera 3D objekt som man kan manipulera. I och med att AR är ett så pass ungt medium har man inte satt alla riktlinjer än för hur utformningen av en AR-applikation ska se ut vilket, kan komma att resultera i vissa hinder. Ett sådant hinder som vi har sett är hur man fysiskt utför gester och interagerar med 3D objekt. Vi har därför valt att arbeta med hur man på ett så effektivt sätt som möjligt ska kunna utföra dessa interaktioner, då det idag inte finns någon riktigt standard och olika applikationer använder sig av olika gester för olika interaktioner, vilket inte är användarvänligt utan förvirrande. Med hjälp av teoretiska ramverk har vi fått förståelse för mediet och har även lagt en grund för den övriga studien. Vi har även utfört en kartläggning av interaktioner i redan existerande applikationer, vi har gjort en workshop med yrkesverksamma och ett användartest där vi har undersökt hur användaren själv vill utföra interaktionerna. Med hjälp av dessa har vi kommit fram till ett antal rekommendationer på gester som intuitivt kopplas till en särskild interaktion och särskilda interaktioner. Vi har även definierat problem kopplade till dessa.

    Fulltekst (pdf)
    Att interagera med 3D-objekt i en förstärkt verklighet
  • 208.
    Edström, Jonas
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Friedner, Sol
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Målfokuserad webbdesign2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    HTH är ett danskt bolag som främst säljer exklusiva och kvalitativa kök. HTH har tre mätbara mål för sin webbplats, att besökarna når avdelningarna för e-shop, för boka möte samt använder den digitala designtjänsten. Få besökare når webbplatsens avdelningar för målen, därför är studiens syfte att undersöka hur en webbdesign kan påverka i vilken grad besökarna når fastställda mål för en webbplats. De frågor som har undersökts är vad som är viktigt i utvecklingen av en målanpassad webbdesign, samt hur en redesign kan påverka i vilken grad besökarna når fastställda mål och samtidigt får en positiv upplevelse. Teorikapitlet redogör för litteratur inom design och beteendevetenskap för att förstå olika aspekter av design samt hur en design påverkar användarens upplevelse. Studien har genomförts med en kombination av kvantitativ och kvalitativ metod där samtliga användartester har använt metoderna Tänka-högt och Semantic differential. För att fullfölja studiens syfte delades studien in i tre steg. Första steget var att utifrån HTH:s mål för webbplatsen, analysera den befintliga webbdesignen, där analysen kopplades till litteratur. Utifrån resultatet från steg ett utvecklade studiens författare ett förslag på en korrigerad webbdesign i form av en digital prototyp. Avslutningsvis utfördes användartester för att jämföra och utvärdera den befintliga webbdesignen med författarnas designförslag. Användartesterna utvärderades med fem kriterier för en användbar design, samtidigt som data kopplades till litteratur och analyserades. Det framgick av utvärderingen att webbdesignens struktur och visuella uttryck påverkar hur effektivt besökaren noterar de primära målen för webbplatsen. En mer avskalad webbdesign utför en mindre risk att användaren blir distraherad påväg mot webbplatsens fastställda mål och därmed en ökad chans att de fastställda målen enklare och effektivare nås.

    Fulltekst (pdf)
    fulltext
  • 209.
    Edström, Sofie
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Interior visualization of an office in Braxen 32013Independent thesis Basic level (university diploma), 20 poäng / 30 hpOppgave
    Abstract [en]

    Den här rapporten beskriver ett antal olika visualiseringstekniker som testats med hjälp av 3ds Max Design 2012, Revit Architecture 2012 samt Photoshop CS5. Syftet var att ta reda på om de kunde användas vid interiör visualisering och hur de används. Projektet grundar sig i att White Arkitekter AB arbetar med utvecklingen av sitt blivande kontor i Braxen 3 och de ville testa de olika teknikerna i utvecklingssyfte i samband med designutveckling av kontoret. Visualiseringsteknikerna beskrivs utifrån vad de kan användas till och vad de har används till i de tre olika scener som byggts upp med hjälp av programmen, men även hur arbetsgången fungerade. Viss jämförelse mellan olika tekniker och olika sätt att utföra samma tekniker har gjorts. Till en början beskrivs hur modelleringen av scenerna har gått till. Efter det beskrivs de tekniker som används för att utveckla de tre olika scenerna och för att nå ett resultat i form av ett antal slutrenderingar som sedan redovisas i resultatdelen. Slutsatsen som drogs var att alla de tekniker som beskrivits är tillämpbara för interiör visualisering rent praktiskt, men de kanske inte är tillämpbara av tids- och kostnadsaspekter. Sedan diskuterar författaren kring teknikernas användbarhet och åsikter som utvecklats kring teknikerna och arbetsgången under arbetets genomförande.

    Fulltekst (pdf)
    fulltext
  • 210.
    Eilertsen, Gabriel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik.
    High-resolution simulation and rendering of gaseous phenomena from low-resolution data2010Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Numerical simulations are often used in computer graphics to capture the effects of natural phenomena such as fire, water and smoke. However, simulating large-scale events in this way, with the details needed for feature film, poses serious problems. Grid-based simulations at resolutions sufficient to incorporate small-scale details would be costly and use large amounts of memory, and likewise for particle based techniques.

    To overcome these problems, a new framework for simulation and rendering of gaseous phenomena is presented in this thesis. It makes use of a combination of different existing concepts for such phenomena to resolve many of the issues in using them separately, and the result is a potent method for high-detailed simulation and rendering at low cost.

    The developed method utilizes a slice refinement technique, where a coarse particle input is transformed into a set of two-dimensional view-aligned slices, which are simulated at high resolution. These slices are subsequently used in a rendering framework accounting for light scattering behaviors in participating media to achieve a final highly detailed volume rendering outcome. However,the transformations from three to two dimensions and back easily introduces visible artifacts, so a number of techniques have been considered to overcome these problems, where e.g. a turbulence function is used in the final volume density function to break up possible interpolation artifacts.

    Fulltekst (pdf)
    fulltext
  • 211. Bestill onlineKjøp publikasjonen >>
    Eilertsen, Gabriel
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    The high dynamic range imaging pipeline: Tone-mapping, distribution, and single-exposure reconstruction2018Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    Techniques for high dynamic range (HDR) imaging make it possible to capture and store an increased range of luminances and colors as compared to what can be achieved with a conventional camera. This high amount of image information can be used in a wide range of applications, such as HDR displays, image-based lighting, tone-mapping, computer vision, and post-processing operations. HDR imaging has been an important concept in research and development for many years. Within the last couple of years it has also reached the consumer market, e.g. with TV displays that are capable of reproducing an increased dynamic range and peak luminance.

    This thesis presents a set of technical contributions within the field of HDR imaging. First, the area of HDR video tone-mapping is thoroughly reviewed, evaluated and developed upon. A subjective comparison experiment of existing methods is performed, followed by the development of novel techniques that overcome many of the problems evidenced by the evaluation. Second, a largescale objective comparison is presented, which evaluates existing techniques that are involved in HDR video distribution. From the results, a first open-source HDR video codec solution, Luma HDRv, is built using the best performing techniques. Third, a machine learning method is proposed for the purpose of reconstructing an HDR image from one single-exposure low dynamic range (LDR) image. The method is trained on a large set of HDR images, using recent advances in deep learning, and the results increase the quality and performance significantly as compared to existing algorithms.

    The areas for which contributions are presented can be closely inter-linked in the HDR imaging pipeline. Here, the thesis work helps in promoting efficient and high-quality HDR video distribution and display, as well as robust HDR image reconstruction from a single conventional LDR image.

    Delarbeid
    1. A comparative review of tone-mapping algorithms for high dynamic range video
    Åpne denne publikasjonen i ny fane eller vindu >>A comparative review of tone-mapping algorithms for high dynamic range video
    2017 (engelsk)Inngår i: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, Vol. 36, nr 2, s. 565-592Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Tone-mapping constitutes a key component within the field of high dynamic range (HDR) imaging. Its importance is manifested in the vast amount of tone-mapping methods that can be found in the literature, which are the result of an active development in the area for more than two decades. Although these can accommodate most requirements for display of HDR images, new challenges arose with the advent of HDR video, calling for additional considerations in the design of tone-mapping operators (TMOs). Today, a range of TMOs exist that do support video material. We are now reaching a point where most camera captured HDR videos can be prepared in high quality without visible artifacts, for the constraints of a standard display device. In this report, we set out to summarize and categorize the research in tone-mapping as of today, distilling the most important trends and characteristics of the tone reproduction pipeline. While this gives a wide overview over the area, we then specifically focus on tone-mapping of HDR video and the problems this medium entails. First, we formulate the major challenges a video TMO needs to address. Then, we provide a description and categorization of each of the existing video TMOs. Finally, by constructing a set of quantitative measures, we evaluate the performance of a number of the operators, in order to give a hint on which can be expected to render the least amount of artifacts. This serves as a comprehensive reference, categorization and comparative assessment of the state-of-the-art in tone-mapping for HDR video.

    sted, utgiver, år, opplag, sider
    WILEY, 2017
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-139637 (URN)10.1111/cgf.13148 (DOI)000404474000048 ()
    Konferanse
    38th Annual Conference of the European-Association-for-Computer-Graphics (EUROGRAPHICS)
    Merknad

    Funding Agencies|Swedish Foundation for Strategic Research (SSF) [IIS11-0081]; Linkoping University Center for Industrial Information Technology (CENIIT); Swedish Research Council through the Linnaeus Environment CADICS

    Tilgjengelig fra: 2017-08-16 Laget: 2017-08-16 Sist oppdatert: 2018-05-15
    2. Evaluation of Tone Mapping Operators for HDR-Video
    Åpne denne publikasjonen i ny fane eller vindu >>Evaluation of Tone Mapping Operators for HDR-Video
    2013 (engelsk)Inngår i: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, Vol. 32, nr 7, s. 275-284Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Eleven tone-mapping operators intended for video processing are analyzed and evaluated with camera-captured and computer-generated high-dynamic-range content. After optimizing the parameters of the operators in a formal experiment, we inspect and rate the artifacts (flickering, ghosting, temporal color consistency) and color rendition problems (brightness, contrast and color saturation) they produce. This allows us to identify major problems and challenges that video tone-mapping needs to address. Then, we compare the tone-mapping results in a pair-wise comparison experiment to identify the operators that, on average, can be expected to perform better than the others and to assess the magnitude of differences between the best performing operators.

    sted, utgiver, år, opplag, sider
    Wiley, 2013
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-104135 (URN)10.1111/cgf.12235 (DOI)000327310800029 ()
    Prosjekter
    VPS
    Tilgjengelig fra: 2014-02-07 Laget: 2014-02-07 Sist oppdatert: 2018-05-15bibliografisk kontrollert
    3. Real-time noise-aware tone mapping
    Åpne denne publikasjonen i ny fane eller vindu >>Real-time noise-aware tone mapping
    2015 (engelsk)Inngår i: ACM Transactions on Graphics, ISSN 0730-0301, E-ISSN 1557-7368, ISSN 0730-0301, Vol. 34, nr 6, s. 198:1-198:15, artikkel-id 198Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Real-time high quality video tone mapping is needed for manyapplications, such as digital viewfinders in cameras, displayalgorithms which adapt to ambient light, in-camera processing,rendering engines for video games and video post-processing. We propose a viable solution for these applications by designing a videotone-mapping operator that controls the visibility of the noise,adapts to display and viewing environment, minimizes contrastdistortions, preserves or enhances image details, and can be run inreal-time on an incoming sequence without any preprocessing. To ourknowledge, no existing solution offers all these features. Our novelcontributions are: a fast procedure for computing local display-adaptivetone-curves which minimize contrast distortions, a fast method for detailenhancement free from ringing artifacts, and an integrated videotone-mapping solution combining all the above features.

    sted, utgiver, år, opplag, sider
    New York, NY, USA: Association for Computing Machinery (ACM), 2015
    Emneord
    Tone mapping, high dynamic range video, display algorithms
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-122681 (URN)10.1145/2816795.2818092 (DOI)000363671200035 ()
    Konferanse
    SIGGRAPH Aisa 2015
    Prosjekter
    VPS
    Forskningsfinansiär
    Swedish Foundation for Strategic Research
    Tilgjengelig fra: 2015-11-14 Laget: 2015-11-14 Sist oppdatert: 2018-05-15
    4. A HIGH DYNAMIC RANGE VIDEO CODEC OPTIMIZED BY LARGE-SCALE TESTING
    Åpne denne publikasjonen i ny fane eller vindu >>A HIGH DYNAMIC RANGE VIDEO CODEC OPTIMIZED BY LARGE-SCALE TESTING
    2016 (engelsk)Inngår i: 2016 IEEE INTERNATIONAL CONFERENCE ON IMAGE PROCESSING (ICIP), IEEE , 2016, s. 1379-1383Konferansepaper, Publicerat paper (Fagfellevurdert)
    Abstract [en]

    While a number of existing high-bit depth video compression methods can potentially encode high dynamic range (HDR) video, few of them provide this capability. In this paper, we investigate techniques for adapting HDR video for this purpose. In a large-scale test on 33 HDR video sequences, we compare 2 video codecs, 4 luminance encoding techniques (transfer functions) and 3 color encoding methods, measuring quality in terms of two objective metrics, PU-MSSIM and HDR-VDP-2. From the results we design an open source HDR video encoder, optimized for the best compression performance given the techniques examined.

    sted, utgiver, år, opplag, sider
    IEEE, 2016
    Serie
    IEEE International Conference on Image Processing ICIP, ISSN 1522-4880
    Emneord
    High dynamic range (HDR) video; HDR video coding; perceptual image metrics
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-134106 (URN)10.1109/ICIP.2016.7532584 (DOI)000390782001093 ()978-1-4673-9961-6 (ISBN)
    Konferanse
    23rd IEEE International Conference on Image Processing (ICIP)
    Tilgjengelig fra: 2017-01-22 Laget: 2017-01-22 Sist oppdatert: 2018-05-15
    5. HDR image reconstruction from a single exposure using deep CNNs
    Åpne denne publikasjonen i ny fane eller vindu >>HDR image reconstruction from a single exposure using deep CNNs
    Vise andre…
    2017 (engelsk)Inngår i: ACM Transactions on Graphics, ISSN 0730-0301, E-ISSN 1557-7368, Vol. 36, nr 6, artikkel-id 178Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    Camera sensors can only capture a limited range of luminance simultaneously, and in order to create high dynamic range (HDR) images a set of different exposures are typically combined. In this paper we address the problem of predicting information that have been lost in saturated image areas, in order to enable HDR reconstruction from a single exposure. We show that this problem is well-suited for deep learning algorithms, and propose a deep convolutional neural network (CNN) that is specifically designed taking into account the challenges in predicting HDR values. To train the CNN we gather a large dataset of HDR images, which we augment by simulating sensor saturation for a range of cameras. To further boost robustness, we pre-train the CNN on a simulated HDR dataset created from a subset of the MIT Places database. We demonstrate that our approach can reconstruct high-resolution visually convincing HDR results in a wide range of situations, and that it generalizes well to reconstruction of images captured with arbitrary and low-end cameras that use unknown camera response functions and post-processing. Furthermore, we compare to existing methods for HDR expansion, and show high quality results also for image based lighting. Finally, we evaluate the results in a subjective experiment performed on an HDR display. This shows that the reconstructed HDR images are visually convincing, with large improvements as compared to existing methods.

    sted, utgiver, år, opplag, sider
    ASSOC COMPUTING MACHINERY, 2017
    Emneord
    HDR reconstruction; inverse tone-mapping; deep learning; convolutional network
    HSV kategori
    Identifikatorer
    urn:nbn:se:liu:diva-143943 (URN)10.1145/3130800.3130816 (DOI)000417448700008 ()
    Konferanse
    10th ACM SIGGRAPH Conference and Exhibition on Computer Graphics and Interactive Techniques in Asia
    Merknad

    Funding Agencies|Linkoping University Center for Industrial Information Technology (CENIIT); Swedish Science Council [2015-05180]; Wallenberg Autonomous Systems Program (WASP)

    Tilgjengelig fra: 2017-12-29 Laget: 2017-12-29 Sist oppdatert: 2018-05-15
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    The high dynamic range imaging pipeline: Tone-mapping, distribution, and single-exposure reconstruction
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  • 212.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Forssén, Per-Erik
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    BriefMatch: Dense binary feature matching for real-time optical flow estimation2017Inngår i: Proceedings of the Scandinavian Conference on Image Analysis (SCIA17) / [ed] Puneet Sharma, Filippo Maria Bianchi, Springer, 2017, Vol. 10269, s. 221-233Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Research in optical flow estimation has to a large extent focused on achieving the best possible quality with no regards to running time. Nevertheless, in a number of important applications the speed is crucial. To address this problem we present BriefMatch, a real-time optical flow method that is suitable for live applications. The method combines binary features with the search strategy from PatchMatch in order to efficiently find a dense correspondence field between images. We show that the BRIEF descriptor provides better candidates (less outlier-prone) in shorter time, when compared to direct pixel comparisons and the Census transform. This allows us to achieve high quality results from a simple filtering of the initially matched candidates. Currently, BriefMatch has the fastest running time on the Middlebury benchmark, while placing highest of all the methods that run in shorter than 0.5 seconds.

  • 213.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Kronander, Joel
    Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska fakulteten.
    Denes, Gyorgy
    University of Cambridge, England.
    Mantiuk, Rafal K.
    University of Cambridge, England.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    HDR image reconstruction from a single exposure using deep CNNs2017Inngår i: ACM Transactions on Graphics, ISSN 0730-0301, E-ISSN 1557-7368, Vol. 36, nr 6, artikkel-id 178Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Camera sensors can only capture a limited range of luminance simultaneously, and in order to create high dynamic range (HDR) images a set of different exposures are typically combined. In this paper we address the problem of predicting information that have been lost in saturated image areas, in order to enable HDR reconstruction from a single exposure. We show that this problem is well-suited for deep learning algorithms, and propose a deep convolutional neural network (CNN) that is specifically designed taking into account the challenges in predicting HDR values. To train the CNN we gather a large dataset of HDR images, which we augment by simulating sensor saturation for a range of cameras. To further boost robustness, we pre-train the CNN on a simulated HDR dataset created from a subset of the MIT Places database. We demonstrate that our approach can reconstruct high-resolution visually convincing HDR results in a wide range of situations, and that it generalizes well to reconstruction of images captured with arbitrary and low-end cameras that use unknown camera response functions and post-processing. Furthermore, we compare to existing methods for HDR expansion, and show high quality results also for image based lighting. Finally, we evaluate the results in a subjective experiment performed on an HDR display. This shows that the reconstructed HDR images are visually convincing, with large improvements as compared to existing methods.

  • 214.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Larsson, Per
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    A versatile material reflectance measurement system for use in production2011Inngår i: Proceedings of SIGRAD 2011. Evaluations of Graphics and Visualization — Efficiency, Usefulness, Accessibility, Usability, November 17–18, 2011, KTH, Stockholm, Sweden, Linköping University Electronic Press, 2011, s. 69-76Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we present our developed bidirectional reflectance distribution capturing pipeline. It includes a constructed gonioreflectometer for reflectance measurements, as well as extensive software for operation, data visualization and parameter fitting of analytic models. Our focus is on the flexible user interface, aimed at material appearance creation for computer graphics, and targeted both for production and research employment.

    Key challenges have been in providing a user friendly and effective software for functioning in a production environment, abstracting the details of the calculations involved in the reflectance capturing and fitting. We show how a combination of well-tuned tools can make complex processes such as reflectance calibration, measurement and fitting highly automated in a fast and easy work-flow, from material scanning to model parameters optimized for use in rendering. At the same time, the developed software provides a modifiable interface for detailed control. The importance of having good reflectance visualizations is also demonstrated, where the software plotting tools are able to show vital details of a reflectance distribution, giving valuable insight in to a materials properties and a models accuracy of fit to measured data, on both a local and global level.

    Fulltekst (pdf)
    fulltext
  • 215.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Mantiuk, R. K.
    University of Cambridge, England.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    A comparative review of tone-mapping algorithms for high dynamic range video2017Inngår i: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, Vol. 36, nr 2, s. 565-592Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Tone-mapping constitutes a key component within the field of high dynamic range (HDR) imaging. Its importance is manifested in the vast amount of tone-mapping methods that can be found in the literature, which are the result of an active development in the area for more than two decades. Although these can accommodate most requirements for display of HDR images, new challenges arose with the advent of HDR video, calling for additional considerations in the design of tone-mapping operators (TMOs). Today, a range of TMOs exist that do support video material. We are now reaching a point where most camera captured HDR videos can be prepared in high quality without visible artifacts, for the constraints of a standard display device. In this report, we set out to summarize and categorize the research in tone-mapping as of today, distilling the most important trends and characteristics of the tone reproduction pipeline. While this gives a wide overview over the area, we then specifically focus on tone-mapping of HDR video and the problems this medium entails. First, we formulate the major challenges a video TMO needs to address. Then, we provide a description and categorization of each of the existing video TMOs. Finally, by constructing a set of quantitative measures, we evaluate the performance of a number of the operators, in order to give a hint on which can be expected to render the least amount of artifacts. This serves as a comprehensive reference, categorization and comparative assessment of the state-of-the-art in tone-mapping for HDR video.

  • 216.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Mantiuk, Rafal K.
    University of Cambridge, England.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    A HIGH DYNAMIC RANGE VIDEO CODEC OPTIMIZED BY LARGE-SCALE TESTING2016Inngår i: 2016 IEEE INTERNATIONAL CONFERENCE ON IMAGE PROCESSING (ICIP), IEEE , 2016, s. 1379-1383Konferansepaper (Fagfellevurdert)
    Abstract [en]

    While a number of existing high-bit depth video compression methods can potentially encode high dynamic range (HDR) video, few of them provide this capability. In this paper, we investigate techniques for adapting HDR video for this purpose. In a large-scale test on 33 HDR video sequences, we compare 2 video codecs, 4 luminance encoding techniques (transfer functions) and 3 color encoding methods, measuring quality in terms of two objective metrics, PU-MSSIM and HDR-VDP-2. From the results we design an open source HDR video encoder, optimized for the best compression performance given the techniques examined.

  • 217.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. IRYSTEC, Canada.
    Mantiuk, Rafal K.
    University of Cambridge, England; IRYSTEC, Canada.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. IRYSTEC, Canada.
    REAL-TIME NOISE-AWARE TONE-MAPPING AND ITS USE IN LUMINANCE RETARGETING2016Inngår i: 2016 IEEE INTERNATIONAL CONFERENCE ON IMAGE PROCESSING (ICIP), IEEE , 2016, s. 894-898Konferansepaper (Fagfellevurdert)
    Abstract [en]

    With the aid of tone-mapping operators, high dynamic range images can be mapped for reproduction on standard displays. However, for large restrictions in terms of display dynamic range and peak luminance, limitations of the human visual system have significant impact on the visual appearance. In this paper, we use components from the real-time noise-aware tone-mapping to complement an existing method for perceptual matching of image appearance under different luminance levels. The refined luminance retargeting method improves subjective quality on a display with large limitations in dynamic range, as suggested by our subjective evaluation.

  • 218.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Mantiuk, Rafal
    University of Cambridge.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Real-time noise-aware tone mapping2015Inngår i: ACM Transactions on Graphics, ISSN 0730-0301, E-ISSN 1557-7368, ISSN 0730-0301, Vol. 34, nr 6, s. 198:1-198:15, artikkel-id 198Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Real-time high quality video tone mapping is needed for manyapplications, such as digital viewfinders in cameras, displayalgorithms which adapt to ambient light, in-camera processing,rendering engines for video games and video post-processing. We propose a viable solution for these applications by designing a videotone-mapping operator that controls the visibility of the noise,adapts to display and viewing environment, minimizes contrastdistortions, preserves or enhances image details, and can be run inreal-time on an incoming sequence without any preprocessing. To ourknowledge, no existing solution offers all these features. Our novelcontributions are: a fast procedure for computing local display-adaptivetone-curves which minimize contrast distortions, a fast method for detailenhancement free from ringing artifacts, and an integrated videotone-mapping solution combining all the above features.

  • 219.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik.
    Mantiuk, Rafal
    University of Cambridge, England.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik.
    Single-frame Regularization for Temporally Stable CNNs2019Inngår i: IEEE Conference on Computer Vision and Pattern Recognition, 2019, s. 11176-11185Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Convolutional neural networks (CNNs) can model complicated non-linear relations between images. However, they are notoriously sensitive to small changes in the input. Most CNNs trained to describe image-to-image mappings generate temporally unstable results when applied to video sequences, leading to flickering artifacts and other inconsistencies over time. In order to use CNNs for video material, previous methods have relied on estimating dense frame-to-frame motion information (optical flow) in the training and/or the inference phase, or by exploring recurrent learning structures. We take a different approach to the problem, posing temporal stability as a regularization of the cost function. The regularization is formulated to account for different types of motion that can occur between frames, so that temporally stable CNNs can be trained without the need for video material or expensive motion estimation. The training can be performed as a fine-tuning operation, without architectural modifications of the CNN. Our evaluation shows that the training strategy leads to large improvements in temporal smoothness. Moreover, for small datasets the regularization can help in boosting the generalization performance to a much larger extent than what is possible with naive augmentation strategies.

  • 220.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Mantiuk, Rafal
    University of Cambridge, UK.
    Evaluation of tone mapping operators for HDR video2016Inngår i: High dynamic range video: from acquisition to display and applications / [ed] Frédéric Dufaux, Patrick Le Callet, Rafal K. Mantiuk, Marta Mrak, London, United Kingdom: Academic Press, 2016, 1st, s. 185-206Kapittel i bok, del av antologi (Annet vitenskapelig)
    Abstract [en]

    Tone mapping of HDR-video is a challenging filtering problem. It is highly important to develop a framework for evaluation and comparison of tone mapping operators. This chapter gives an overview of different approaches for how evalation of tone mapping operators can be conducted, including experimental setups, choice of input data, choice of tone mapping operators, and the importance of parameter tweaking for fair comparisons. This chapter also gives examples of previous evaluations with a focus on the results from the most recent evaluation conducted by Eilertsen et. al [reference]. This results in a classification of the currently most commonly used tone mapping operators and overview of their performance and possible artifacts.

  • 221.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Wanat, Robert
    Bangor University, United Kingdom.
    Mantiuk, Rafal
    Bangor University, United Kingdom.
    Perceptually based parameter adjustments for video processing operations2014Inngår i: ACM SIGGRAPH Talks 2014, ACM Press, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Extensive post processing plays a central role in modern video production pipelines. A problem in this context is that many filters and processing operators are very sensitive to parameter settings and that the filter responses in most cases are highly non-linear. Since there is no general solution for performing perceptual calibration of image and video operators automatically, it is often necessary to manually perform tweaking of multiple parameters. This is an iterative process which requires instant visual feedback of the result in both the spatial and temporal domains. Due to large filter kernels, computational complexity, high frame rate, and image resolution it is, however, often very time consuming to iteratively re-process and tweak long video sequences.We present a new method for rapidly finding the perceptual minima in high-dimensional parameter spaces of general video operators. The key idea of our algorithm is that the characteristics of an operator can be accurately described by interpolating between a small set of pre-computed parameter settings. By computing a perceptual linearization of the parameter space of a video operator, the user can explore this interpolated space to find the best set of parameters in a robust way. Since many operators are dependent on two or more parameters, we formulate this as a general optimization problem where we let the objective function be determined by the user’s image assessments. To demonstrate the usefulness of our approach we show a set of use cases (see the supplementary material) where our algorithm is applied to computationally expensive video operations.

    Fulltekst (pdf)
    fulltext
  • 222.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Wanat, Robert
    Bangor University, UK.
    Mantiuk, Rafal
    Bangor University, UK.
    Survey and Evaluation of Tone Mapping Operators for HDR-video2013Inngår i: Siggraph 2013 Talks, ACM Press, 2013Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    This work presents a survey and a user evaluation of tone mapping operators (TMOs) for high dynamic range (HDR) video, i.e. TMOs that explicitly include a temporal model for processing of variations in the input HDR images in the time domain. The main motivations behind this work is that: robust tone mapping is one of the key aspects of HDR imaging [Reinhard et al. 2006]; recent developments in sensor and computing technologies have now made it possible to capture HDR-video, e.g. [Unger and Gustavson 2007; Tocci et al. 2011]; and, as shown by our survey, tone mapping for HDR video poses a set of completely new challenges compared to tone mapping for still HDR images. Furthermore, video tone mapping, though less studied, is highly important for a multitude of applications including gaming, cameras in mobile devices, adaptive display devices and movie post-processing. Our survey is meant to summarize the state-of-the-art in video tonemapping and, as exemplified in Figure 1 (right), analyze differences in their response to temporal variations. In contrast to other studies, we evaluate TMOs performance according to their actual intent, such as producing the image that best resembles the real world scene, that subjectively looks best to the viewer, or fulfills a certain artistic requirement. The unique strength of this work is that we use real high quality HDR video sequences, see Figure 1 (left), as opposed to synthetic images or footage generated from still HDR images.

    Fulltekst (pdf)
    abstract
  • 223.
    Eilertsen, Gabriel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Wanat, Robert
    Bangor University, Wales .
    Mantiuk, Rafal K.
    Bangor University, Wales .
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Evaluation of Tone Mapping Operators for HDR-Video2013Inngår i: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, Vol. 32, nr 7, s. 275-284Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Eleven tone-mapping operators intended for video processing are analyzed and evaluated with camera-captured and computer-generated high-dynamic-range content. After optimizing the parameters of the operators in a formal experiment, we inspect and rate the artifacts (flickering, ghosting, temporal color consistency) and color rendition problems (brightness, contrast and color saturation) they produce. This allows us to identify major problems and challenges that video tone-mapping needs to address. Then, we compare the tone-mapping results in a pair-wise comparison experiment to identify the operators that, on average, can be expected to perform better than the others and to assess the magnitude of differences between the best performing operators.

    Fulltekst (pdf)
    Preprint
  • 224.
    Ek, Nathalie
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Realtidsrendering av försimulerade partiklar2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master thesis presents a method for real-time streaming of pre-simulated particle systems. The particle systems are simulated offline in any software and then saved as an Alembic file. This Alembic file is then imported into Frostbite and can be loaded at run-time. The result of this master the- sis work is the implementation of a streaming and rendering framework for pre-simulated particles. The implementation contains only basic shad- ing and lighting due to the time constraints of the work but the streaming part features an advanced solution to get predictable and manageable CPU and memory overhead. The implentation performs well and works satisfac- tory.

    Fulltekst (pdf)
    fulltext
  • 225.
    Ekberg, Amanda
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Karlsson, Josefine
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Designade brandsläckare: En studie om designade brandsläckare för hemmet2018Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    Abstract not availalble/Abstract är inte tillgängligt.

    Fulltekst (pdf)
    Designade brandsläckare: En studie om designade brandsläckare för hemmet
  • 226.
    Ekeskär, Andreas
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Rudberg, Martin
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Kommunikations- och transportsystem. Linköpings universitet, Tekniska högskolan.
    Vennström, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Third-party logistics in large construction projects: A SCM perspective2014Inngår i: Proceedings of the 21st EurOMA Conference: Operations Management in an innovative economy, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The purpose of this paper is to investigate the use of 3PL providers in large construction projects, and to identify main drivers and barriers, as well as the resulting effects, when implementing SCM by the use of 3PL providers. This is done by the means of a literature review and an explorative case study, the latter being a large hospital construction project. The results show positive performance effects in terms of increased productivity, resources utilization, and delivery performance, but also that there are challenges when it comes to organizational setting, policy adherence and supply chain coordination.

  • 227.
    Eklund, Anders
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Tekniska högskolan.
    Ohlsson, Henrik
    Linköpings universitet, Institutionen för systemteknik, Elektroniksystem. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Tekniska högskolan.
    Andersson, Mats
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Tekniska högskolan.
    Rydell, Joakim
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Tekniska högskolan.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Tekniska högskolan.
    Knutsson, Hans
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Tekniska högskolan.
    Balancing an Inverted Pendulum by Thinking A Real-Time fMRI Approach2009Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    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.

    Fulltekst (pdf)
    Balancing an Inverted Pendulum by Thinking A Real-Time fMRI Approach
  • 228.
    Eklöf, Matilda
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Den rosa elefanten i rummet - en studie kring användningen av rosa inom design för en manlig målgrupp2017Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [sv]

    Studien syftar till att undersöka hur färgen rosa uppfattas ur ett genusperspektiv samt hur färgen med ansatsen kritisk design kan användas på schampoförpackningar för män för att bryta existerande könsnormer. Metoden forskning genom design används och baserat på denna har en skala av schampoförpackningar som använder sig av rosa i olika grader tagits fram. En förberedande studie genomfördes i form av en kvantitativ enkätundersökning för att få en inblick i hur rosa uppfattas idag och resultatet visade att det finns en problematik kring hur rosa används relaterat till genus. Baserat på detta genomfördes sedan en förstudie där teorier gällande normer, färg och förpackningsdesign studerades parallellt med att intervjuer och observationsstudier genomfördes. Syftet var att samla in information till grund för och som kan användas vid designprocessen. Under designprocessen togs olika förslag på design av schampoförpackningar för män där rosa och andra feminint kodade element hade applicerats fram. En skala bestående av sju förpackningar med ökande grad av rosa togs fram. Denna skala värderades sedan med en kvantitativ enkätundersökning med 127 deltagande och kompletterande kvalitativa intervjuer med nio personer. Data från dessa undersökningar analyserades sedan. Resultatet visar på att rosa fortfarande är starkt feminint könskodat men att det finns en vilja hos både män och kvinnor att bryta denna. Det finns tydliga skillnader mellan schampoförpackningar riktade till män och kvinnor. Resultatet visade också att rosa kan användas inom förpackningsdesign för män och att färgen kan användas i högre grad om den kombineras med andra förpackningselement som är mer maskulint kodade.

    Fulltekst (pdf)
    The pink elephant in the room - a study on the usage of pink when designing for a male target group
  • 229.
    Ekman, Viktor
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Moen, Jesper
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Exteriör och interiör visualisering av ett bostadshus i 3ds max2014Independent thesis Basic level (university diploma), 20 poäng / 30 hpOppgave
    Abstract [en]

    Denna rapport beskriver och drar jämförelser mellan olika visualiseringstekniker i 3D Studio Max och Adobe Photoshop CS3. Syftet med studien är att undersöka olika visualiserings- och renderingstekniker för att se vilka tekniker som ger ett smidigast och mest verklighetstroget resultat utifrån olika förutsättningar. Studien grundar sig på en huvudfråga och två stycken underfrågor. Hur skapar man ett effektivt och verklighetstroget visualiseringsresultat av ett bostadskvarter för intressenter? • Vilka fördelar och nackdelar finns det med olika visualiseringstekniker? • Vilka metoder ger ett verklighetstroget visualiseringsresultat vid interiör respektive exteriör visualisering? Slutsatsen med studien är att varje situation är unik och att det finns fördelar och nackdelar med varje teknik och metod i de olika programmen. För att nå ett önskat slutresultat så gäller det att lära sig hur varje metod fungerar och sedan anpassa den utifrån varje enskild situation.

    Fulltekst (pdf)
    fulltext
  • 230.
    Eksmo, Veronica S
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Götestrand, Karin
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    This is not a porcelain swan: A graphic campaign concept for second hand stores with charity purpose2016Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    Konsumtionen i världen ökar och ett sätt att motverka den miljöpåverkan det medför är återanvändning genom second hand. Många second hand-verksamheter har välgörenhetssyfte och för att uppmuntra till köp krävs god marknadsföring samt ett starkt varumärke och där spelar butiken en central roll. Föreliggande studie har därför undersökt hur ett grafiskt kampanjmaterial för användning i en second hand-butik med välgörenhetssyfte kan vara utformat för att öka betalningsviljan. För att besvara forskningsfrågan har forskning genom design använts. Tidigare forskning och en förstudie har legat till grund för designarbetet genom vilket två koncept kallade Oväntad kombo och På köpet har tagit fram. Båda koncepten förmedlar vad pengarna vid köp går till, men har olika angreppssätt. Koncepten värderades genom kvalitativa intervjuer, vilka visade att det fanns stora risker att konceptet På köpet missuppfattades, medan Oväntad kombo upplevdes som tydligt och väckte positiva känslor. Värderingen resulterade i att konceptet Oväntad kombo rekommenderas för användning i butik. En kvantitativ jämförelse visade dessutom att konceptet leder till mätbar ökad betalningsvilja.

    Fulltekst (pdf)
    fulltext
  • 231.
    Eliasson, Clara
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Jonsson, Frida
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Nedskräpningsfrågor i ett flödesvänligt filmformat2019Independent thesis Basic level (university diploma), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    En studie som undersöker hur en svensk stiftelse genom ett filmkoncept för sociala medier kan nå en svår målgrupp. Studien har utgått från ett verkligt behov och samarbete med stiftelsen Håll Sverige Rent som upplever ett problem att nå unga vuxna i åldrarna 16-29 år. Resultatet blev ett filmkoncept som ska fungera som en mall för stiftelsen.

    Fulltekst (pdf)
    Nedskräpningsfrågor i ett flödesvänligt filmformat
  • 232.
    Ellegård, Kajsa
    et al.
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Vrotsou, Katerina
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    En tidsgeografisk studie av strukturen i lärares vardag2013Rapport (Annet vitenskapelig)
    Abstract [sv]

    Rapporten En tidsgeografisk studie av lärares vardag bygger på det dagboksmaterial som Skolverket samlade in under våren 2012 från drygt 3 600 lärare. Den besvarar frågor som:

    • När under dagen utförs arbetsrelaterade aktiviteter och var utförs de?
    • Har aktiviteterna lång eller kort varaktighet?
    • Vilka skillnader och likheter finns mellan lärare i olika årskurser? V
    • ilka arbetsrelaterade aktiviteter utförs efter lektionstid och var genomförs de?
    • Finns det sekvenser av aktiviteter som återkommer hos många lärare i yrkesvardagen?

    I rapporten visualiseras grundskollärares tidsanvändning så att deras aktiviteter under dygnet beskrivs i den tidsordning som de genomförs.

    Resultatet visar att lärares arbetsvecka i mångt och mycket ser likartad ut. Det tar sig uttryck i att lärare arbetar ungefär lika långa dagar, vistas ungefär lika lång tid i skolan, genomför till viss del samma aktivitetssekvenser. De flesta arbetsrelaterade aktiviteterna genomförs i skolan, men många lärare utför också arbetsrelaterade aktiviteter på kvällstid i hemmet. Påtagliga skillnader framgår mellan veckans fyra första dagar och fredagar och mellan lärare i olika årskurser i flera olika avseenden.

    Lärares yrkesvardag analyseras med hjälp av de tidsgeografiska begreppen projekt och restriktioner. Lärares förvärvsarbete är ett individprojekt och detta ska passa in både i skolans organisationsprojekt (med målet att skapa förutsättningar för elevernas lärande) och i det egna hushållets organisationsprojekt (med målet att skapa ett bra liv för hushållsmedlemmarna).

    Skolans organisationsprojekt innebär auktoritetsrestriktioner för lärare genom att de måste följa avtal, arbeta enligt bestämda undervisningsscheman och delta i föreskrivna möten. För lärarnas del innebär bland annat schemaläggningen av undervisningen att kopplingsrestriktioner uppstår. Lärare som vill eller behöver arbeta tillsammans måste ha tidsmässiga möjligheter och någon ledig lokal för att genomföra sina gemensamma aktiviteter och då kan inte någon av dem vara schemalagd för lektioner. Kopplingsrestriktioner uppträder t ex när tätt packade scheman och högt tryck på skolans lokaler och försvårar för samarbete mellan lärare.

    När arbetsrelaterade aktiviteter utförs hemma på kvällstid vävs skolans organisationsprojekt in i lärarhushållets privata projekt. Det innebär att lärares individprojekt förvärvsarbete blir en kopplingsrestriktion som hindrar henne/honom från att samtidigt delta i hushållets privata projekt. Kanske skulle t ex utökad tillgång till arbetsutrymmen i skolan där aktiviteter kan utföras ostört och koncentrerat, möjliggöra för lärare att genomföra mer av sina arbetsrelaterade aktiviteter på dagtid och i skolan?

    Visualiseringen av den kontextuella tidsanvändningen och analysen av de kopplingsrestriktioner som uppstår i lärarnas yrkesvardag indikerar att andra former av organisering av en del arbetsrelaterade aktiviteterna skulle kunna frigöra tid för lärarnas kärnaktiviteter.

    Fulltekst (pdf)
    En tidsgeografisk studie av strukturen i lärares vardag
  • 233.
    Ellegård, Kajsa
    et al.
    Linköpings universitet, Filosofiska fakulteten. Linköpings universitet, Institutionen för tema, Tema teknik och social förändring.
    Vrotsou, Katerina
    Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik.
    Widén, Joakim
    Department of engineering science, Uppsala University.
    VISUAL-TimePAcTS / energy use: a software application for visualizing energy use from activities performed2015Inngår i: Socio-technical perspectives on sustainable energy systems / [ed] Jonas Anshelm, Kajsa Ellegård, Jenny Palm, Harald Rohracher, Linköping: Linköping University , 2015, s. 127-145Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 234.
    Ellegård, Kajsa
    et al.
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Vrotsou, Katerina
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Widén, Joakim
    Teknikvetenskaper, fastat illståndets fysik, Uppsala universitet,.
    VISUAL-TimePAcTS/energy use: a soft ware application for visualizing energy use from activities performed2010Inngår i: Conference proceedings 3rd International Scientific Conference on “Energy systems with IT” / [ed] Erik Dahlqvist & Jenny Palm, 2010, s. 1-16Konferansepaper (Fagfellevurdert)
    Abstract [en]

    We will present the software application VISUAL-TimePAcTS/energy use. The application shows, in a flexible way, the energy use of individuals, households, groups and whole populations which is calculated through individuals’ performed activities. Input data is diary logs for the 24 hours of the day. There are several visualizations opportunities. First, all activities performed by each individual in the population can be shown. Second, activity patterns (i.e. combinations and repetitions of activities) can be identified and represented. Third, the activities that request energy for their performance can be visualized. Fourth, “load curves” that show the power demand can be constructed, within the application, from a set of rules relating energy consumed by different appliances to performed activities requiring these appliances. We will also present principles used for doing the activity categorization (a categorization scheme), and how we hope to develop the software further. The application opens new opportunities to make use of national time use surveys.

    Fulltekst (pdf)
    VISUAL-TimePAcTS/energy use : a soft ware application for visualizing energy use from activities performed
  • 235.
    Ellegård, Kajsa
    et al.
    Linköpings universitet, Institutionen för tema, Tema teknik och social förändring. Linköpings universitet, Filosofiska fakulteten.
    Widén, Joakim
    Uppsala universitet; Institutionen för teknikvetenskaper; Fasta tillståndets fysik.
    Vrotsou, Katerina
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Appliances Facilitating Everyday Life - Electricity Use Derived from Daily Activities2011Inngår i: Proceeding from the World Renewable Energy Congress - Sweden, 8-13 May, 2011 / [ed] Bahram Moshfegh, Linköping University Electronic Press , 2011, s. 1031-1038Konferansepaper (Fagfellevurdert)
    Abstract [en]

    The purpose of this paper is to present how, using a visualization method, electricity use can be derived from the everyday activity patterns of household members. Target groups are, on the one hand, professionals in the energy sector and energy advisors who need more knowledge about household energy use, and, on the other hand, household members wanting to reduce the energy use by revealing their own habits and thereby finding out how changed activity performance may influence electricity use. The focus is on the relation between utilizing electric appliances to perform everyday life activities and the use of electricity. The visualization method is based on the time-geographic approach developed by Hägerstrand and includes a model that estimates appliance electricity use from household members’ activities. Focus, in this paper, is put on some basic activities performed to satisfy daily life needs: cooking and use of information, communication and entertainment devices. These activities appear frequently in the everyday life of households, even though not all household members perform them all. The method is applied on a data material comprising time-diaries written by 463 individuals (aged 10 to 85+) in 179 households in different parts of Sweden. The visualization method reveals when and for how long activities that claim electric appliances are performed by which individual(s). It also shows electricity load curves generated from the use of appliances at different levels, such as individual, household and group or population levels. At household level the method can reveal which household members are the main users of electricity, i.e. the division of labour between household members. Thereby it also informs about whom could be approached by energy companies and energy advisors in information campaigns. The main result of the study is that systematic differences in activity patterns in subgroups of a population can be identified (e.g. men and women) but that directed information based on these patterns has to be made with care and with the risk of making too broad generalizations.

    Fulltekst (pdf)
    fulltext
  • 236.
    Emadi, Mohammad
    et al.
    Qualcomm Technol Inc, CA 95110 USA.
    Miandji, Ehsan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    A Performance Guarantee for Orthogonal Matching Pursuit Using Mutual Coherence2018Inngår i: Circuits, systems, and signal processing, ISSN 0278-081X, E-ISSN 1531-5878, Vol. 37, nr 4, s. 1562-1574Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we present a new performance guarantee for the orthogonal matching pursuit (OMP) algorithm. We use mutual coherence as a metric for determining the suitability of an arbitrary overcomplete dictionary for exact recovery. Specifically, a lower bound for the probability of correctly identifying the support of a sparse signal with additive white Gaussian noise and an upper bound for the mean square error is derived. Compared to the previous work, the new bound takes into account the signal parameters such as dynamic range, noise variance, and sparsity. Numerical simulations show significant improvements over previous work and a much closer correlation to empirical results of OMP.

    Fulltekst (pdf)
    fulltext
  • 237.
    Emadi, Mohammad
    et al.
    Qualcomm Technol Inc, CA USA.
    Miandji, Ehsan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Unger, Jonas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    OMP-based DOA estimation performance analysis2018Inngår i: Digital signal processing (Print), ISSN 1051-2004, E-ISSN 1095-4333, Vol. 79, s. 57-65Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper, we present a new performance guarantee for Orthogonal Matching Pursuit (OMP) in the context of the Direction Of Arrival (DOA) estimation problem. For the first time, the effect of parameters such as sensor array configuration, as well as signal to noise ratio and dynamic range of the sources is thoroughly analyzed. In particular, we formulate a lower bound for the probability of detection and an upper bound for the estimation error. The proposed performance guarantee is further developed to include the estimation error as a user-defined parameter for the probability of detection. Numerical results show acceptable correlation between theoretical and empirical simulations. (C) 2018 Elsevier Inc. All rights reserved.

  • 238.
    Emin, Yad
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Nilsson, Victoria
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    The development of pictograms for use on food products containing nuts2014Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [en]

    Denna studie undersöker hur märkning på livsmedelsförpackningar kan göras tydligare för personer med nötallergi. Tidigare studier visar att det finns brister i dagens märkningar och att detta i sin tur skapar problem. Därför har denna studie som avsikt att ta reda på hur allergeninformation för nötallergiker kan förbättras och göras tydligare. Detta tillämpas genom att studiens forskare tar fram ett designförslag som ska komplettera obligatorisk märkning på livsmedelsförpackningar. För att ta reda på hur detta designförslag ska utformas inleds designprocessen med en litteraturstudie och där en cross-case-analys genomförs. Genom denna analys hittas trender och mönster i tidigare studier. Därefter tillämpas en design space-analys där trenderna, olika designprinciper samt forskarnas egna kunskaper kombineras för att utforska olika designalternativ. Alternativ som i slutändan skapar en grund för en design. Studiens forskare skapar symboler, närmare bestämt piktogram. Eftersom jordnötsallergi och nötallergi är olika typer av allergier skapas två stycken piktogram. Piktogrammen, som är cirkelformade, får ett varnande budskap som förmedlas med hjälp av färgerna gul och svart. Piktogrammen utvärderas och testas genom att fem personliga intervjuer genomförs. Intervjuerna görs med personer som är allergiska mot jordnötter och/eller nötter. Forskarna testar piktogrammen genom att placera dem på en livsmedelsförpackning och ställer sedan frågor om bl.a. första intryck, färger och placering. Analysen visar att piktogram mycket väl kan användas som kompletterande märkning på livsmedelsförpackningar. Vidare konstateras det att valet av färg inverkar på den association som sändaren vill förmedla. Intervjuerna visar även att piktogrammen fördelaktigt kan placeras på förpackningens framsida. Studiens syfte har uppnåtts till viss mån, då intervjuerna visar att det ena piktogrammet behöver utvecklas för att tydligare kommunikation för nötallergiker ska kunna skapas.

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  • 239.
    Engelbrektsson, Martin
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Lilja, Marcus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Data Driven Visualization Tool for Game Telemetry2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis describes and evaluates the implementation of a telemetry tool prototype for the game engine Stingray. Arbitrary data can be chosen from a database and visualized in an interactive 3D viewport in the program. The implemented visualization method is a scatter plot with optional color mapping. A MongoDB server communicates with the editor via a native DLL written in C/C++ which in turn can send data to the rendering engine via JavaScript-Lua communication. Several implemented and continuously improved pipelines are discussed and analyzed throughout the report. The tool is designed to be data driven. Advantages and disadvantages of doing so are discussed. In the final chapter future improvements and ideas of expanding the plug-in are discussed.

    Fulltekst (pdf)
    Data Driven Visualization Tool for Game Telemetry
  • 240.
    Engelke, Wito
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Hotz, Ingrid
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Evolutionary Lines for Flow Visualization2018Inngår i: EuroVis 2018, 20th EG/VGTC Conference on Visualization, 4-8 June, Brno, Czech Republic / [ed] Jimmy Johansson and Filip Sadlo and Tobias Schreck, The Eurographics Association , 2018, s. 7-11Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this work we explore evolutionary algorithms for selected a visualization application. We demonstrate its potential using an example from flow visualization showing promising first results. Evolutionary algorithms, as guided search approach, find close-to-optimal solutions with respect to some fitness function in an iterative process using biologically motivated mechanisms like selection, mutation and recombination. As such, they provide a powerful alternative to filtering methods commonly used in visualization where the space of possible candidates is densely sampled in a pre-processing step from which the best candidates are selected and visualized. This approach however tends to be increasingly inefficient with growing data size or expensive candidate computations resulting in large pre-processing times. We present an evolutionary algorithm for the problem of streamline selection to highlight features of interest in flow data. Our approach directly optimizes the solution candidates with respect to a user selected fitness function requiring significantly less computations. At the same time the problem of possible under-sampling is solved since we are not tied to a preset resolution. We demonstrate our approach on the well-known flow around an obstacle as case with a two-dimensional search space. The blood flow in an aneurysm serves as an example with a three-dimensional search space. For both, the achieved results are comparable to line filtering approaches with much less line computations.

    Fulltekst (pdf)
    Evolutionary Lines for Flow Visualization
  • 241.
    Engelke, Wito
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Lawonn, Kai
    Department of Simulation and Graphics, University of Magdeburg, Germany / Institute for Computational Visualistics, University of Koblenz‐Landau, Germany.
    Preim, Bernhard
    Department of Simulation and Graphics, University of Magdeburg, Germany.
    Hotz, Ingrid
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Autonomous Particles for Interactive Flow Visualization2019Inngår i: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, nr 1, s. 248-259Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present an interactive approach to analyse flow fields using a new type of particle system, which is composed of autonomous particles exploring the flow. While particles provide a very intuitive way to visualize flows, it is a challenge to capture the important features with such systems. Particles tend to cluster in regions of low velocity and regions of interest are often sparsely populated. To overcome these disadvantages, we propose an automatic adaption of the particle density with respect to local importance measures. These measures are user defined and the systems sensitivity to them can be adjusted interactively. Together with the particle history, these measures define a probability for particles to multiply or die, respectively. There is no communication between the particles and no neighbourhood information has to be maintained. Thus, the particles can be handled in parallel and support a real‐time investigation of flow fields. To enhance the visualization, the particles' properties and selected field measures are also used to specify the systems rendering parameters, such as colour and size. We demonstrate the effectiveness of our approach on different simulated vector fields from technical and medical applications.

    Fulltekst (pdf)
    Autonomous Particles for Interactive Flow Visualization
  • 242.
    Englesson, Dan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Improving the visual quality of computer generated crowds for feature film production2012Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this thesis, several different methods for improving the visual quality of a crowd system for feature film production are presented. The implementations were made for the Moving Picture Company for their crowd system software ALICE. The methods implemented and presented in this thesis have made improvements on the basic skinning methods by introducing twisting and scaling of the bones with a method called Stretchable and Twistable Bone Skinning. Also, complex and detailed deformations on crowd characters such as muscle bulging and wrinkles on clothes, are now possible due to the implementation of Pose Space Deformation methods which interpolates stored complex and time-consuming deformations onto a mesh. Several known pose space deformation methods were implemented and compared and resulted in an other method trying to reduce the current pose space deformation method’s limitations and is presented as Three-Joint Pose Space Deformation. In this thesis, a novel method for Dynamic Pose Space Deformation is also presented and a dynamic spring-damper approximation deformation method was also implemented, enabling crowd characters to have dynamic effects, such as jiggling of fat and muscle bouncing, due to joint accelerations.

    Fulltekst (pdf)
    fulltext
  • 243.
    Englund, Carl
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Evaluation of cloud-based infrastructures for scalable applications2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The usage of cloud computing in order to move away from local servers and infrastructure have grown enormously the last decade. The ability to quickly scale capacity of servers and their resources at once when needed is something that can both be a price saver for companies and help them deliver high end products that will function correctly at all times even under heavy load to their customers. To meet todays challenges, one of the strategic directions of Attentec, a software company located in Linköping, is to examine the world of cloud computing in order to deliver robust and scalable applications to their customers. This thesis investigates the usage of cloud services in order to deploy scalable applications which can adapt to usage peaks within minutes.

    Fulltekst (pdf)
    fulltext
  • 244.
    Englund, Rickard
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ultrasound Surface Extraction for Advanced Skin Rendering2013Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report evaluates possibilities to combine volumetric ultrasound (us) data together with the recent work published on advanced skin rendering techniques. We focus mainly on how to filter us data and localize surfaces within us data. We also evaluate recent skin rendering techniques in order to have a good understanding of what is needed from the us for rendering realistic skin. us data is acquired using sonography and have a low signal-to-noise ratio by nature, this makes it harder to extract surfaces compared to other medical data acquisition methods such as ct and mr. This report present an algorithm which implements a variational classification technique to emphasize surfaces within us and using a rbf network to fit an implicit function to these surfaces. Using this approach presented we have successfully extract smooth meshes from the noisy us data.

    Fulltekst (pdf)
    fulltext
  • 245.
    Englund, Rickard
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Kottravel, Sathish
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Ropinski, Timo
    Visual Computing Research Group, Ulm University.
    A Crowdsourcing System for Integrated and Reproducible Evaluation in Scientific Visualization2016Inngår i: 2016 IEEE Pacific Visualization Symposium (PacificVis), IEEE Computer Society, 2016, s. 40-47Konferansepaper (Fagfellevurdert)
    Abstract [en]

    User evaluations have gained increasing importance in visualization research over the past years, as in many cases these evaluations are the only way to support the claims made by visualization researchers. Unfortunately, recent literature reviews show that in comparison to algorithmic performance evaluations, the number of user evaluations is still very low. Reasons for this are the required amount of time to conduct such studies together with the difficulties involved in participant recruitment and result reporting. While it could be shown that the quality of evaluation results and the simplified participant recruitment of crowdsourcing platforms makes this technology a viable alternative to lab experiments when evaluating visualizations, the time for conducting and reporting such evaluations is still very high. In this paper, we propose a software system, which integrates the conduction, the analysis and the reporting of crowdsourced user evaluations directly into the scientific visualization development process. With the proposed system, researchers can conduct and analyze quantitative evaluations on a large scale through an evaluation-centric user interface with only a few mouse clicks. Thus, it becomes possible to perform iterative evaluations during algorithm design, which potentially leads to better results, as compared to the time consuming user evaluations traditionally conducted at the end of the design process. Furthermore, the system is built around a centralized database, which supports an easy reuse of old evaluation designs and the reproduction of old evaluations with new or additional stimuli, which are both driving challenges in scientific visualization research. We will describe the system's design and the considerations made during the design process, and demonstrate the system by conducting three user evaluations, all of which have been published before in the visualization literature.

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    Download (pdf)
    Appendix
  • 246.
    Englund, Rickard
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Lundin Palmerius, Karljohan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Hotz, Ingrid
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Touching Data: Enhancing Visual Exploration of Flow Data with Haptics2018Inngår i: Computing in science & engineering (Print), ISSN 1521-9615, E-ISSN 1558-366X, Vol. 20, nr 3, s. 89-100Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    n/a

  • 247.
    Englund, Rickard
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Ropinski, Timo
    Visual Computing Research Group, Ulm University.
    Evaluating the perception of semi-transparent structures in direct volume rendering techniques2016Inngår i: Proceeding SA '16 SIGGRAPH ASIA 2016 Symposium on Visualization, ACM Digital Library, 2016Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Direct volume rendering (DVR) provides the possibility to visualize volumetric data sets as they occur in many scientific disciplines. A key benefit of DVR is that semi-transparency can be facilitated in order to convey the complexity of the visualized data. Unfortunately, semi-transparency introduces new challenges in spatial comprehension of the visualized data, as the ambiguities inherent to semi-transparent representations affect spatial comprehension. Accordingly, many visualization techniques have been introduced to enhance the spatial comprehension of DVR images. In this paper, we conduct a user evaluation in which we compare standard DVR with five visualization techniques which have been proposed to enhance the spatial comprehension of DVR images. In our study, we investigate the perceptual performance of these techniques and compare them against each other to find out which technique is most suitable for different types of data and purposes. In order to do this, a large-scale user study was conducted with 300 participants who completed a number of micro-tasks designed such that the aggregated feedback gives us insight on how well these techniques aid the end user to perceive depth and shape of objects. Within this paper we discuss the tested techniques, present the conducted study and analyze the retrieved results.

    Fulltekst (pdf)
    fulltext
  • 248.
    Englund, Rickard
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Ropinski, Timo
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Quantitative and Qualitative Analysis of the Perception of Semi-Transparent Structures in Direct Volume Rendering2018Inngår i: Computer graphics forum (Print), ISSN 0167-7055, E-ISSN 1467-8659, Vol. 37, nr 6, s. 174-187Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Abstract Direct Volume Rendering (DVR) provides the possibility to visualize volumetric data sets as they occur in many scientific disciplines. With DVR semi-transparency is facilitated to convey the complexity of the data. Unfortunately, semi-transparency introduces challenges in spatial comprehension of the data, as the ambiguities inherent to semi-transparent representations affect spatial comprehension. Accordingly, many techniques have been introduced to enhance the spatial comprehension of DVR images. In this paper, we present our findings obtained from two evaluations investigating the perception of semi-transparent structures from volume rendered images. We have conducted a user evaluation in which we have compared standard DVR with five techniques previously proposed to enhance the spatial comprehension of DVR images. In this study, we investigated the perceptual performance of these techniques and have compared them against each other in a large-scale quantitative user study with 300 participants. Each participant completed micro-tasks designed such that the aggregated feedback gives insight on how well these techniques aid the user to perceive depth and shape of objects. To further clarify the findings, we conducted a qualitative evaluation in which we interviewed three experienced visualization researchers, in order to find out if we can identify the benefits and shortcomings of the individual techniques.

  • 249.
    Englund, Rickard
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ropinski, Timo
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Ultrasound Surface Extraction Using Radial Basis Functions2014Inngår i: Advances in Visual Computing: 10th International Symposium, ISVC 2014, Las Vegas, NV, USA, December 8-10, 2014, Proceedings, Part II / [ed] George Bebis, Springer Publishing Company, 2014, Vol. 8888, s. 163-172Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Data acquired from ultrasound examinations is of interest not only for the physician, but also for the patient. While the physician uses the ultrasound data for diagnostic purposes the patient might be more interested in beautiful images in the case of prenatal imaging. Ultrasound data is noisy by nature and visually compelling 3D renderings are not always trivial to produce. This paper presents a technique which enables extraction of a smooth surface mesh from the ultrasound data by combining previous research in ultrasound processing with research in point cloud surface reconstruction. After filtering the ultrasound data using Variational Classification we extract a set of surface points. This set of points is then used to train an Adaptive Compactly Supported Radial Basis Functions system, a technique for surface reconstruction of noisy laser scan data. The resulting technique can be used to extract surfaces with adjustable smoothness and resolution and has been tested on various ultrasound datasets.

    Fulltekst (pdf)
    fulltext
  • 250.
    Englund, Rickard
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Ropinski, Timo
    Visual Computing Group, Ulm University, Germany.
    Hotz, Ingrid
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Coherence Maps for Blood Flow Exploration2016Inngår i: VCBM 16: Eurographics Workshop on Visual Computing for Biology and Medicine, Eurographics - European Association for Computer Graphics, 2016, s. 79-88Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Blood flow data from direct measurements (4D flow MRI) or numerical simulations opens new possibilities for the understanding of the development of cardiac diseases. However, before this new data can be used in clinical studies or for diagnosis, it is important to develop a notion of the characteristics of typical flow structures. To support this process we developed a novel blood flow clustering and exploration method. The method builds on the concept of coherent flow structures. Coherence maps for cross-sectional slices are defined to show the overall degree of coherence of the flow. In coherent regions the method summarizes the dominant blood flow using a small number of pathline representatives. In contrast to other clustering approaches the clustering is restricted to coherent regions and pathlines with low coherence values, which are not suitable for clustering and thus are not forced into clusters. The coherence map is based on the Finite-time Lyapunov Exponent (FTLE). It is created on selected planes in the inflow respective outflow area of a region of interest. The FTLE value measures the rate of separation of pathlines originating from this plane. Different to previous work using FTLE we do not focus on separating extremal lines but on local minima and regions of low FTLE intensities to extract coherent flow. The coherence map and the extracted clusters serve as basis for the flow exploration. The extracted clusters can be selected and inspected individually. Their flow rate and coherence provide a measure for their significance. Switching off clusters reduces the amount of occlusion and reveals the remaining part of the flow. The non-coherent regions can also be explored by interactive manual pathline seeding in the coherence map.

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    fulltext
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