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  • 251.
    Engström, Kristina
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Koller, Mikaela
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Real-time visualization of a digital learning platform2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master thesis report presents the development and results of a dashboard developed for Sanoma Utbildning. The learning platform, called SUD - Sanoma Utbildnig Digital, is a combination of exercises and reading material used by both students and teachers. The purpose of the application is to provide Sanoma Utbildning with valuable insights of the activity in SUD and was developed using agile methods. The dashboard should be easy to understand for both employees at Sanoma Utbildning and possible customers. The user interface has been developed with help from theory and by conducting three user evaluations. The data is collected from logs produced by SUD and sent with webhooks to the dashboard. The result is a web based MEAN-stack application visualizing real time data and statistical data of the events in the learning platform.

    Fulltekst (pdf)
    fulltext
  • 252. Engvall, Gustav
    et al.
    Bergström, Fredrik
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik.
    Development of handheld mobile applications for the public sector in Android and iOS using agile Kanban process tool2011Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The innovation progress for municipalities is currently going slowly. Today most of the communication, decision-making, delegation and service of process are still handled via letter mail or phone calls. Companies and municipalities are starting to comprehend this and see opportunities. With the technology that exists today it is possible to speed up the processes when citizens and municipalities comunicate with each other. By migrating from the old way of applying and filing different matters by letter mail to so-called digital e-services, the citizen can apply, complement and get info on how their matter is going directly on the web. Abou AB works with optimizing information handling for municipalities and has recently made it possible for municipalities to eliminate their tedious way of handling matters by traceable web communication. They have a vision to take this to a new level of easement to the municipalities and their citizens by offering these services in mobile phones as so-called apps. One of these contemplated services is to file error reports. The service will offer the citizen to send in a report with attached meta data such as photo and the location of the regarding matter. This will be done by the mobile phones built in hardware in form of camera and GPS. This master’s thesis will describe the work to develop a prototype for filing an error reports in mobile phones that support Android and iOS operating systems.

    The goal for this thesis work is to develop this prototype by means of a process tool called Kanban and investigate if the tool fits the situation properly. The situation is that two persons will work in parallel with slightly different projects. Also the quality and usability of the resulting prototype applications is asserted with qualitative evaluations that results in higher awareness of the defects and suggestions on how to reform and improve the application in a usability point of view.

    The actual implementation work was planned according to a slightly loose Kan- ban paradigm. Kanban is all about improvements along the way and the im- plementation phase is divided into smaller phases with sub goals and recurring process evaluations. Suggestions of improvement regarding the work processes is a result of this. A Kanban board that helps visualize the workflow is used to help team members and project owners to get a good overview of current situa- tions. Several adjustments were made throughout the project and the so-called lead times, the time it takes to complete a task, was shortened in average from the beginning of the project compared to the end of the project.

    Each phase in the implementation part of the thesis work resulted in different functionalities in the application. A phase was two weeks long and ended with a demo were the new functionality was demonstrated. Prior to each demo session everyone at the company where the thesis work was performed was invited. The participants in these sessions were encouraged to give feedback on what they saw to help increase the quality of the applications. The prototype applications resulted in a more easy accessible service to citizens. By cutting out the process steps that previously needed to been done on a computer the

    1application contributes to the possibility of an increased democratization grade for the citizen.

    The investigation regarding if the Kanban process tool was a suitable aid in the implementation part of the project resulted in that it was suitable for the specific situation. By measuring both lead times and other activities that did not concern the implementation work and plot them in a diagram explained why some weeks did not have as high productivity as others.

    To assert the awareness and quality of the developed applications in terms of usability a so-called heuristic evaluation was performed. This qualitative eval- uation resulted in a set of usability problems. These problems were all graded into different priority to be solved and some was given suggestions on how to be solved. The main purpose with this evaluation was to find the problems and document them to possible future programmers if the prototype will go into production. The result of this evaluation has increased the usability of the application and consequently the quality.

    Fulltekst (pdf)
    fulltext
  • 253.
    Ericson, Åsa
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Mesic, Merima
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Packaging design and consumer response – an evaluation of design characteristics in the private label lower price tier2016Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [en]

    Allt fler dagligvarukedjor erbjuder produkter vid sidan av leverantörernas, dessa säljs under ett flertal egna varumärken som delas in i olika prissegment. Med det ökade utbudet av varumärken blir konsumenterna allt mer selektiva vilket ställer högre krav på en tydlig differentiering för att varumärkena ska kunna konkurrera och nå målsegmentet. Denna studie undersöker hur lågprisvarumärkena differentierar sig genom förpackningsdesign och vilka konsumentreaktioner det medför. Detta görs genom att identifiera och utvärdera de typiska stildrag som idag tycks gälla vid formgivningen av distributörers egna lågprisförpackningar. Stildragen fastställs utifrån kulör, typografi, bildspråk och visuell hierarki. De lågprisvarumärken som undersöktes var Ica Basic, Coop X-tra och Eldorado, vilka tillhör de tre ledande aktörerna på den svenska livsmedelsmarknaden; Ica, Coop och Axfood. För att uppfylla syftet och besvara de preciserade frågorna genomfördes en visuell datainsamling samt fokuserade gruppintervjuer. Under den visuella datainsamlingen fotograferades aktuella förpackningar i sina respektive butiker, där bilderna sedan användes för att identifiera de gemensamma stildragen. För att utvärdera de identifierade stildragen genomfördes därefter fokusgruppsintervjuer som undersökte konsumenternas reaktioner på förpackningarna. Studien visade att stildragen som lågprisvarumärkena använder sig av utgörs av ett utbrett användande av kulören vitt tillsammans med mättade kulörer, ofta i stora block. För typografin används grova linjära typsnitt satta i stor teckengrad. Stildragen för bildspråk utgörs av användandet av avskalade produktbilder samt enkla illustrationer. Den visuella hierarkin utmärktes av att förpackningsdesignen inkluderade få designelement och ett tydligt fokus på produktnamn, produktbild och logotyp. Stildragen har visat sig vara väl inarbetade indikatorer för lågpris hos konsumenterna då de har lärt sig associera dessa med lågprissegmentet. Det har även visat sig att stildragen medför associationer till låg kvalitet och att de överlag ofta uppfattas som icke attraktiva, detta väljer dock många att bortse från då engagemanget rörande livsmedelsprodukter visat sig vara lågt när det kommer till förbrukningsvaror. Att signalera en högre kvalitet och attraktivitet utan att avvika från stildragen har visat sig möjligt då Eldorados alternativa implementering väckt dessa känslor hos flertalet av studiens deltagare. Dock så medför detta även en problematik då varumärkets differentiering som lågpris tycks vara otydligare och därför riskerar att bli insorterad i fel prisgrupp hos konsumenterna.

    Fulltekst (pdf)
    fulltext
  • 254.
    Eriksson, Jonatan
    et al.
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Kardiologi. Linköpings universitet, Hälsouniversitetet.
    Bolger, Ann F.
    Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Carlhäll, Carl-Johan
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Ebbers, Tino
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Fysiologi. Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik.
    Spatial heterogeneity of 4D relative pressure fields in the human left ventricle2013Manuskript (preprint) (Annet vitenskapelig)
    Abstract [en]

    Blood flow throughout the cardiovascular system is driven by pressure differences generated by the contraction and relaxation of the heart, where blood accelerates from high to low pressure areas. Absolute intracardiac pressure cannot be measured noninvasively, but relative pressure can be calculated. The aim of this study was to assess the spatial heterogeneity of the 4D relative pressure fields in the human left ventricle (LV).

    Twelve healthy subjects underwent MRI examination where 4D flow as well as morphological data were acquired. The morphological data were segmented, and the segmentation used as boundary condition when computing relative pressure fields from the pressure Poisson equation using a multi grid solver. The LV lumen was divided according to a seventeen segment model in order to assess spatial heterogeneity and present the extensive amount of data in a comprehensive manner.

    The basal anteroseptal segment shows a significantly lower median pressure than the opposite basal inferolateral segment during both early and late diastolic filling (p<0.0005 and p=0.0024, respectively). Along the long axis, the relative pressure in the apical segments are significantly higher relative to the basal segments (p<0.0005) along both the anteroseptal and inferolateral sides at and after the peaks of E-wave and A-wave.

    During diastole the main pressure differences in the LV occur along the basal-apical axis. However, pressure differences can also be found in the short-axis direction, and may also reflect important aspects of atrioventricular coupling.

  • 255.
    Eriksson, Jonatan
    et al.
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Kardiologi. Linköpings universitet, Hälsouniversitetet.
    Bolger, Ann F.
    Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Ebbers, Tino
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Fysiologi. Linköpings universitet, Hälsouniversitetet. Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik.
    Carlhäll, Carl-Johan
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicin och hälsa, Klinisk fysiologi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Hjärt- och Medicincentrum, Fysiologiska kliniken US.
    Four-dimensional blood flow-specific markers of LV dysfunction in dilated cardiomyopathy2013Inngår i: European Heart Journal Cardiovascular Imaging, ISSN 2047-2404, E-ISSN 2047-2412, Vol. 14, nr 5, s. 417-424Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Aims : Patients with mild heart failure (HF) who are clinically compensated may have normal left ventricular (LV) stroke volume (SV). Despite this, altered intra-ventricular flow patterns have been recognized in these subjects. We hypothesized that, compared with normal LVs, flow in myopathic LVs would demonstrate a smaller proportion of inflow volume passing directly to ejection and diminished the end-diastolic preservation of the inflow kinetic energy (KE).

    Methods and results : In 10 patients with dilated cardiomyopathy (DCM) (49 ± 14 years, six females) and 10 healthy subjects (44 ± 17 years, four females), four-dimensional MRI velocity and morphological data were acquired. A previously validated method was used to separate the LV end-diastolic volume (EDV) into four flow components based on the blood's locations at the beginning and end of the cardiac cycle. KE was calculated over the cardiac cycle for each component. The EDV was larger (P = 0.021) and the ejection fraction smaller (P < 0.001) in DCM compared with healthy subjects; the SV was equivalent (DCM: 77 ± 19, healthy: 79 ± 16 mL). The proportion of the total LV inflow that passed directly to ejection was smaller in DCM (P = 0.000), but the end-diastolic KE/mL of the direct flow was not different in the two groups (NS).

    Conclusion : Despite equivalent LVSVs, HF patients with mild LV remodelling demonstrate altered diastolic flow routes through the LV and impaired preservation of inflow KE at pre-systole compared with healthy subjects. These unique flow-specific changes in the flow route and energetics are detectable despite clinical compensation, and may prove useful as subclinical markers of LV dysfunction.

    Fulltekst (pdf)
    fulltext
  • 256.
    Eriksson, Linnea Viola
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Den animerade musikupplevelsen - en studie om animation som visuellt komplement på Spotify2019Independent thesis Basic level (university diploma), 10,5 poäng / 16 hpOppgave
    Abstract [en]

    Denna studie syftar att undersöka huruvida animation som visuellt komplement på Spotify väcker större engagemang emotionellt än ett statiskt skivomslag. Animerade filmer har tagits fram till sex olika låtar på albumet 99.9% av artisten Kaytranada. Detta har gjorts genom en förstudie i form av en enkät, samt research om de befintliga filmer som finns tillgängliga på Spotify i dagsläget. Efter detta har designarbetet utförts genom brainstorming, explorativt skissande och storyboards. För att utvärdera skapades en värderingsmatris med syfte att välja ut de mest engagerande idéerna, för att sedan fortsätta med digitalt skissande och slutligen animering. Efter detta värderades animationerna gentemot det statiska skivomslaget genom en kvalitativ enkät, såväl som två olika fokusgrupper. Resultatet visade att även om animationerna ansågs något repetitiva så ansåg en majoritet att de var mer engagerande emotionellt än ett statiskt skivomslag.

    Fulltekst (pdf)
    Den animerade musikupplevelsen - en studie om animation som visuellt komplement på Spotify
  • 257.
    Eriksson, Oskar
    et al.
    Linköpings universitet, Institutionen för datavetenskap, Programvara och system. Linköpings universitet, Tekniska fakulteten.
    Rydkvist, Emil
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    An in-depth analysis of dynamically rendered vector-based maps with WebGL using Mapbox GL JS2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The regular way of displaying maps in a web browser is by downloading raster images from a server and lay them side by side to make up a map. If any information on the map is changed, new images has to be downloaded, it cannot be done on the client. The introduction of WebGL opens up a whole new world of delivering advanced graphics content to the end user in a web browser. Utilizing this technology for displaying maps means only the source data is sent to the web browser where the map gets rendered using the device's GPU. This adds a number of benefits such as the ability of changing map appearance on the client, add new features to the map and often less data transfer. It however sets higher expectations of the client device's hardware as it needs to render the map at a high enough frame rate to not appear slow and unresponsive. This thesis investigates a framework for client side map rendering in a web browser, Mapbox GL JS, with focus on performance. It shows how map source data can be generated as well as its corresponding style rules are constructed with performance in mind. It provides benchmarking results of different map data sets with different detail intensity and shows that a device with good GPU performance is needed for an acceptable user experience. It also shows that lowering the amount of rendered detail does not necessarily result in better performance.

    Fulltekst (pdf)
    fulltext
  • 258.
    Eriksson, Pär
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Providing a scalable architecture to support low-latency ad-hoc funnel analysis on custom defined events for an A/B testing use case2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    A/B testing combined with funnel analysis is a highly interesting technique to support data driven decision making. This thesis outlines a scalable architecture that gathers custom defined events and applies funnel analysis to gain valuable insights about user behaviour. The insights of the users are discussed from an A/B testing point of view, however, these insights are just as valuable for scenarios outside A/B testing as well. Custom defined events together with A/B testing is an interesting combination, since it provides opportunities to test different versions of an application against each other, based on relevant metrics. Where the vision is to determine which of the tested application versions that is best. The power to make smart data driven decisions lies in the hand of good data analysis of the end-users. Having pre-defined metrics such as counts, of some sort, is one way to do it. However, it reduces the flexibility to let e.g. application managers to "dig deeper" into what is actually happening. Funnel analysis is a technique to analyze sequences, and can be used to analyze user behaviour in a sequential matter. There are different techniques to provide such tools, e.g. with Google Analytics, users can pre-define funnel steps that they want Google Analytics to register when events are logged. This thesis will instead strive to not require anything being pre-defined and also make it possible, at high scale, provide dynamic low latency queries. A proof of concept architecture has been presented in this thesis, to support two problematic ends of a spectrum, that is; at scale, both to store custom events, and at the same time be able to interactively run dynamic low latency funnel analysis on the events.

    Fulltekst (pdf)
    Providing a scalable architecture to support low-latency ad-hoc funnel analysis on custom defined events for an A/B testing use case
  • 259.
    Erlandsson, Tobias
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Hallström, Gustav
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Audial Support for Visual Dense Data Display2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    This report presents an application developed for evaluating the possible benefits of using audial support in a visualization application. A hypothesis is presented where the idea is that sonification might help users perceive densities in data-sets with large amounts of data points. The application presents a scatterplot and a parallel coordinates plot. To both plots audial support is added where the amplitude of the sound is used for representing the amount of points in different areas of the plots. The method is evaluated through user studies where ability to find maximum points, finding equal densities and appreciation of the sounds is investigated. Quantitative and qualitative results show improvements when finding maximum points in tight clusters both in parallel coordinates and scatter plots. This is a first step when investigating this area of visualization spurring further research.

    Fulltekst (pdf)
    Audial Support for Visual Dense Data Display
  • 260. Ernvik, Aron
    et al.
    Bergström, Staffan
    Lundström, Claes
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik.
    Ljung, Patric
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik.
    Ynnerman, Anders
    Linköpings universitet.
    Image data set compression based on viewing parameters for storing medical image data from multidimensional data sets, related systems, methods and computer products2012Patent (Annet (populærvitenskap, debatt, mm))
  • 261.
    Esbjörnsson, Joakim
    et al.
    Karolinska Inst, Sweden; Univ Oxford, England; Katholieke Univ Leuven, Belgium.
    Mild, Mattias
    Department of Microbiology, Public Health Agency of Sweden, Stockholm, Sweden.
    Audelin, Anne
    Department of Microbiological Diagnostics and Virology, Statens Serum Institut, Copenhagen, Denmark.
    Fonager, Jannik
    Department of Microbiological Diagnostics and Virology, Statens Serum Institut, Copenhagen, Denmark.
    Skar, Helena
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Jorgensen, Louise Bruun
    Department of Microbiological Diagnostics and Virology, Statens Serum Institut, Copenhagen, Denmark.
    Liitsola, Kirsi
    Department of Infectious Diseases, National Institute for Health and Welfare, Helsinki, Finland.
    Björkman, Per
    Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden.
    Bratt, Göran
    Department of Clinical Science and Education, Venhalsan, Stockholm South General Hospital, Stockholm, Sweden.
    Gisslén, Magnus
    Department of Infectious Diseases, Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
    Sönnerborg, Anders
    Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden; Division of Clinical Microbiology, Karolinska Institute, Stockholm, Sweden; Department of Infectious Diseases, Karolinska University Hospital, Stockholm, Sweden.
    Nielsen, Claus
    Department of Microbiological Diagnostics and Virology, Statens Serum Institut, Copenhagen, Denmark.
    Medstrand, Patrik
    Department of Translational Medicine, Lund University, Malmö, Sweden.
    Albert, Jan
    Department of Microbiology Tumor and Cell Biology, Karolinska Institute, Stockholm, Sweden; Department of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden.
    HIV-1 transmission between MSM and heterosexuals, and increasing proportions of circulating recombinant forms in the Nordic Countries2016Inngår i: VIRUS EVOLUTION, ISSN 2057-1577, Vol. 2, nr 1, artikkel-id vew010Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Increased knowledge about HIV-1 transmission dynamics in different transmission groups and geographical regions is fundamental for assessing and designing prevention efforts against HIV-1 spread. Since the first reported cases of HIV infection during the early 1980s, the HIV-1 epidemic in the Nordic countries has been dominated by HIV-1 subtype B and MSM transmission. HIV-1 pol sequences and clinical data of 51 per cent of all newly diagnosed HIV-1 infections in Sweden, Denmark, and Finland in the period 2000-2012 (N = 3,802) were analysed together with a large reference sequence dataset (N = 4,537) by trend analysis and phylogenetics. Analysis of the eight dominating subtypes and CRFs in the Nordic countries (A, B, C, D, G, CRF01_AE, CRF02_AG, and CRF06_cpx) showed that the subtype B proportion decreased while the CRF proportion increased over the study period. A majority (57 per cent) of the Nordic sequences formed transmission clusters, with evidence of mixing both geographically and between transmission groups. Detailed analyses showed multiple occasions of transmissions from MSM to heterosexuals and that active transmission clusters more often involved single than multiple Nordic countries. The strongest geographical link was between Denmark and Sweden. Finally, Denmark had a larger proportion of heterosexual domestic spread of HIV-1 subtype B (75 per cent) compared with Sweden (49 per cent) and Finland (57 per cent). We describe different HIV-1 transmission patterns between countries and transmission groups in a large geographical region. Our results may have implications for public health interventions in targeting HIV-1 transmission networks and identifying where to introduce such interventions.

    Fulltekst (pdf)
    fulltext
  • 262.
    Eskilson, Klas
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Creating User Interfaces Using Web-based Technologies to Support Rapid Prototyping in a Desktop Astrovisualization Software2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this report, the development and implementation of a desktop user interface framework is presented. It is built using web technologies and the Javascript framework React together with a web socket server to render the graphical user interface in an OpenGL environment. This is done by using the open-source framework Chromium Embedded Framework (CEF). The resulting framework and implementation has proven successful, with promising results both from a performance perspective and from a development rapidness perspective.

    Fulltekst (pdf)
    Creating User Interfaces Using Web-based Technologies to Support Rapid Prototyping in a Desktop Astrovisualization Software
  • 263.
    Eskilson, Siri
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Pedersen, Kajsa
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Red banderoles and swedish flags - a study in the relationship between politics and visual identity within ten political youth associations2014Independent thesis Basic level (degree of Bachelor), 20 poäng / 30 hpOppgave
    Abstract [en]

    2014 är det supervalår i Sverige. Det innebär intensiv marknadsföring för de olika politiska intressena i många olika kanaler. För många, men kanske speciellt för unga människor, kan detta bli en förvirrande period av budskap och åsikter som på olika sätt ska värderas och tas ställning till. De politiska ungdomsförbunden riktar sig till personer mellan sex och 25 år, och hör för det mesta till ett så kallat moderparti, men har egna politiska agendor, grafiska profiler och marknadsföring. Den mesta av marknadsföringen sker genom någon slags grafiskt material, och för att de politiska budskapen verkligen ska nå fram till alla unga på bästa sätt, borde det grafiska materialet också rent visuellt tala för innehållet. Den här studien syftar till att undersöka om det finns samband mellan politik och grafiska profiler hos de politiska ungdomsförbunden. Då studier på sambandet mellan politik och grafiskt material visat sig vara ett relativt outforskat område som det är svårt att hitta exakt data om, är detta en kvalitativ tvärsnittsstudie. Tio politiska ungdomsförbund valdes ut för granskning med grund i moderpartiernas storlek i riksdagsvalet 2010. Vidare samlades data om dessa in genom kvalitativa dokument och audiovisuella kanaler, vilket exempelvis innefattar de politiska ungdomsförbundens grafiska manualer och webbsidor. Studien visar på samband mellan politiken och de grafiska profilernas. Dessa uppstod mellan förbunden som ingår i blockpolitiken, men även mellan förbund på skilda delar av skalan som hade andra aspekter än blockpolitik gemensamt.

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    fulltext
  • 264.
    Etiene, Tiago
    et al.
    University of Utah, UT 84112 USA .
    Jönsson, Daniel
    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.
    Scheidegger, Carlos
    ATandT Labs Research, NJ 07932 USA .
    Comba, Joao L. D.
    University of Federal Rio Grande do Sul, Brazil .
    Gustavo Nonato, Luis
    University of Sao Paulo, Brazil .
    Kirby, Robert M.
    University of Utah, UT 84112 USA .
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Silva, Claudio T.
    NYU, NY 11201 USA .
    Verifying Volume Rendering Using Discretization Error Analysis2014Inngår i: IEEE Transactions on Visualization and Computer Graphics, ISSN 1077-2626, E-ISSN 1941-0506, Vol. 20, nr 1, s. 140-154Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We propose an approach for verification of volume rendering correctness based on an analysis of the volume rendering integral, the basis of most DVR algorithms. With respect to the most common discretization of this continuous model (Riemann summation), we make assumptions about the impact of parameter changes on the rendered results and derive convergence curves describing the expected behavior. Specifically, we progressively refine the number of samples along the ray, the grid size, and the pixel size, and evaluate how the errors observed during refinement compare against the expected approximation errors. We derive the theoretical foundations of our verification approach, explain how to realize it in practice, and discuss its limitations. We also report the errors identified by our approach when applied to two publicly available volume rendering packages.

    Fulltekst (pdf)
    fulltext
  • 265.
    Evangelista, Gianpaolo
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Physical Model of the Slide Guitar: An Approach Based on Contact Forces2012Inngår i: Proceedings of Audio Engineering Society Convention 132, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we approach the synthesis of the slide guitar, which is a particular play mode of the guitar where continuous tuning of the tones is achieved by sliding a metal orglass piece, the bottleneck, along thestrings on the guitar neck side. The bottleneck constitues a unilateral constraint for the string vibration.Dynamics is subject to friction, scraping, textured displacement and collisions. The presented model is physically inspired and is based on a dynamic model of friction, together with a geometrical model of the textured displacements and a model for collisions of the string with the bottlenck. These models are suitablefor implementation in a digital waveguide computational scheme for the 3D vibration of the string, where continuous pitch bending is achieved by allpass filters to approximate fractional delays, friction is captured by nonlinear state-space systems in the slide junction and textured displacements by signal injection at avariable point in the waveguide.

    Fulltekst (pdf)
    fulltext
  • 266.
    Evangelista, Gianpaolo
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Physical Model of the String-Fret Interaction2011Inngår i: Proc. of Digital Audio Effect Conf., 2011, s. 345-351.Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, a model for the interaction of the strings with the frets in a guitar or other fretted string instruments is introduced. In the two-polarization representation of the string oscillations it is observed that the string interacts with the fret in different ways. While the vertical oscillation is governed by perfect or imperfect clamping of the string on the fret, the horizontal oscillation is subject to friction of the string over the surface of the fret. The proposed model allows, in particular, for the accurate evaluation of the elongation of the string in the two modes, which gives rise to audible dynamic detuning. The realization of this model into a structurally passive system for use in digital waveguide synthesis is detailed. By changing the friction parameters, the model can be employed in fretless instruments too, where the string directly interacts with the neck surface.

    Fulltekst (pdf)
    fulltext
  • 267.
    Evangelista, Gianpaolo
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Physically inspired playable models of guitar, a tutorial2010Inngår i: Proc. 4th International Symposium on Digital Communications, Control and Signal Processing (ISCCSP), 2010, s. 1-4Konferansepaper (Fagfellevurdert)
  • 268.
    Evangelista, Gianpaolo
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Time and Frequency Warping of Musical Signals2011Inngår i: DAFX: digital audio effects / [ed] Udo Zölzer, John Wiley & Sons, 2011, 2, s. 447-471Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 269.
    Evangelista, Gianpaolo
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Dörfler, Monika
    University of Vienna, Austria.
    Matusiak, Ewa
    University of Vienna, Austria.
    Phase vocoders with arbitrary frequency band selection2012Inngår i: Proceedings of the 9th Sound and Music Computing Conference, Copenhagen, Denmark, 2012, s. 442-449Konferansepaper (Annet vitenskapelig)
  • 270.
    Evangelista, Gianpaolo
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Eckerholm, Fredrik
    Sony Ericsson Mobile Communication.
    Player-Instrument Interaction Models for Digital Waveguide Synthesis of Guitar: Touch and Collisions2010Inngår i: IEEE TRANSACTIONS ON AUDIO SPEECH AND LANGUAGE PROCESSING, ISSN 1558-7916, Vol. 18, nr 4, s. 822-832Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Physically inspired sound synthesis techniques have been devised for several instruments including guitar. Less well studied are methods to model the interactions of the player with strings and of the strings with other mechanical parts of the instrument. In this paper, we present methods based on simple scattering junctions to be inserted at various points along a digital waveguide simulating transversal wave propagation along a string. These junctions, which are derived using a balanced perturbation method for displacement wave variables, connect the waveguide with the external stimuli provided by the player or with objects that are part of the instrument. A model for plucking is revisited and improved. New nonlinear structures for the accurate model of collisions are developed. The proposed junctions achieve realistic synthesis of the interaction of the plucking finger or pick with the string, of the interaction of the fingers on the neck-side hand with strings, such as in the production of harmonics, and of the strings themselves with frets or fingerboard in a fretless instrument.

    Fulltekst (pdf)
    FULLTEXT01
  • 271.
    Evangelista, Gianpaolo
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Marchand, Sylvain
    University of Bordeaux, France.
    Plumbley, Mark D.
    Queen Mary University of London, UK.
    Vincent, Emmanuel
    INRIA-Rennes, France .
    Sound Source Separation2011Inngår i: DAFX: digital audio effects / [ed] Udo Zölzer, John Wiley & Sons, 2011, 2, s. 551-588Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 272.
    Evangelista, Gianpaolo
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Smith III, Julius Orion
    CCRMA, Stanford University, California, USA.
    Structurally Passive Scattering Element for Modeling Guitar Pluck Action2010Inngår i: Proc. of Digital Audio Effect Conf., Graz, Austria, 2010, s. 10-17Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper we propose new models for the plucking interaction of the player with the string for use with digital waveguide simulation of guitar. Unlike the previously presented models, the new models are based on structurally passive scattering junctions,which have the main advantage of being properly scaled for use infixed-point waveguide implementations and of guaranteeing stability independently of the plucking excitation. In a first model we start from the Cuzzucoli-Lombardo equa-tions [1], within the Evangelista-Eckerholm [2] propagation formulation, in order to derive the passive scattering junction by means of bilinear transformation. In a second model we start from equations properly modeling the finger compliance by means of a spring. In a third model we formalize the interaction in terms ofdriving impedances. The model is also extended using nonlinear (feathering) compliance models.

    Fulltekst (pdf)
    fulltext
  • 273.
    Falck, Camilla
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Gråd, Hanna
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Nära och kära - en fallstudie av hur en logotyp kan utformas för en närproducerande gård2017Independent thesis Basic level (degree of Bachelor), 10,5 poäng / 16 hpOppgave
    Abstract [sv]

    Följande fallstudie syftar till att undersöka hur en logotyp för en närproducerande gård kan se ut för att spegla verksamhetens kärna och värdeord. Gården som studeras är producent av jordgubbar. Forskning genom design har tillämpats för att besvara syftet. Tidigare forskning och en inledande studie där värdeorden förtroende, välsmakande och närproducerande togs fram låg till grund för designprocessen där åtta logotypförslag togs fram. För att värdera logotypförslagen genomfördes en intervju med uppdragsgivaren samt en diskussion med en fokusgrupp. Resultatet visar spekulativt att hierarkin i en logotyp för en närproducerande gård bör vara tydlig för att utstråla förtroende. Logotypen bör innehålla ett föreställande och verklighetstroget objekt, i detta fall en jordgubbe, för att kommunicera välsmakande. Den färg som ansågs mest lämplig för att kommunicera närproducerat var grön. Vidare är de kategorier av logotyper som lämpar sig bäst för syftet emblem och kombinationslogotyper. Avslutningsvis skapades två slutgiltiga logotypförslag utifrån resultatet från värderingen.

    Fulltekst (pdf)
    Nearest och dearest - a case study of how a logotype can be designed for a near producer
  • 274.
    Falk, Martin
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Grottel, Sebastian
    Technische Universität Dresden, Germany.
    Krone, Michael
    University of Stuttgart, Germany.
    Reina, Guido
    University of Stuttgart, Germany.
    Interactive GPU-based Visualization of Large Dynamic Particle Data2016Bok (Fagfellevurdert)
    Abstract [en]

    Prevalent types of data in scientific visualization are volumetric data, vector field data, and particle-based data. Particle data typically originates from measurements and simulations in various fields, such as life sciences or physics. The particles are often visualized directly, that is, by simple representants like spheres. Interactive rendering facilitates the exploration and visual analysis of the data. With increasing data set sizes in terms of particle numbers, interactive high-quality visualization is a challenging task. This is especially true for dynamic data or abstract representations that are based on the raw particle data.

    This book covers direct particle visualization using simple glyphs as well as abstractions that are application-driven such as clustering and aggregation. It targets visualization researchers and developers who are interested in visualization techniques for large, dynamic particle-based data. Its explanations focus on GPU-accelerated algorithms for high-performance rendering and data processing that run in real-time on modern desktop hardware. Consequently, the implementation of said algorithms and the required data structures to make use of the capabilities of modern graphics APIs are discussed in detail. Furthermore, it covers GPU-accelerated methods for the generation of application-dependent abstract representations. This includes various representations commonly used in application areas such as structural biology, systems biology, thermodynamics, and astrophysics.

  • 275.
    Falk, Martin
    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.
    Ljung, Patric
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Treanor, Darren
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Leeds Teaching Hospitals NHS Trust, United Kingdom.
    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.
    Lundström, Claes
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Sectra AB.
    Transfer Function Design Toolbox for Full-Color Volume Datasets2017Inngår i: 2017 IEEE PACIFIC VISUALIZATION SYMPOSIUM (PACIFICVIS), IEEE, IEEE, 2017, s. 171-179Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we tackle the challenge of effective Transfer Function (TF) design for Direct Volume Rendering (DVR) of full-color datasets. We propose a novel TF design toolbox based on color similarity which is used to adjust opacity as well as replacing colors. We show that both CIE L*u*v* chromaticity and the chroma component of YCbCr are equally suited as underlying color space for the TF widgets. In order to maximize the area utilized in the TF editor, we renormalize the color space based on the histogram of the dataset. Thereby, colors representing a higher share of the dataset are depicted more prominently, thus providing a higher sensitivity for fine-tuning TF widgets. The applicability of our TF design toolbox is demonstrated by volume ray casting challenging full-color volume data including the visible male cryosection dataset and examples from 3D histology.

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  • 276.
    Falk, Martin
    et al.
    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.
    Treanor, Darren
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Leeds Teaching Hospitals NHS Trust, United Kingdom.
    Lundström, Claes
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Sectra, Linköping, Sweden.
    Interactive Visualization of 3D Histopathology in Native Resolution2019Inngår i: IEEE Transactions on Visualization and Computer Graphics, ISSN 1077-2626, E-ISSN 1941-0506, Vol. 25, nr 1, s. 1008-1017Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    We present a visualization application that enables effective interactive visual analysis of large-scale 3D histopathology, that is, high-resolution 3D microscopy data of human tissue. Clinical work flows and research based on pathology have, until now, largely been dominated by 2D imaging. As we will show in the paper, studying volumetric histology data will open up novel and useful opportunities for both research and clinical practice. Our starting point is the current lack of appropriate visualization tools in histopathology, which has been a limiting factor in the uptake of digital pathology. Visualization of 3D histology data does pose difficult challenges in several aspects. The full-color datasets are dense and large in scale, on the order of 100,000 x 100,000 x 100 voxels. This entails serious demands on both rendering performance and user experience design. Despite this, our developed application supports interactive study of 3D histology datasets at native resolution. Our application is based on tailoring and tuning of existing methods, system integration work, as well as a careful study of domain specific demands emanating from a close participatory design process with domain experts as team members. Results from a user evaluation employing the tool demonstrate a strong agreement among the 14 participating pathologists that 3D histopathology will be a valuable and enabling tool for their work.

    Fulltekst (pdf)
    fulltext
  • 277.
    Felekidis, Dimitrios
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Advanced Visualization Techniques for Laparoscopic Liver Surgery2015Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Laparoscopic liver surgery is mainly preferred over the traditional open liver surgery due to its unquestionable benefits. This type of surgery is executed by inserting an endoscope camera and the surgical tools inside the patient’s body through small incisions. The surgeons perform the operation by watching the video transmitted from the endoscope camera to high-resolution monitors. The location of the tumors and cysts is examined before and during the operation by the surgeons from the pre-operative CT scans displayed on a different monitor or on printed copies making the operation more difficult to perform.

    In order to make it easier for the surgeons to locate the tumors and cysts and have an insight for the rest of the inner structures of the liver, the 3D models of the liver’s inner structures are extracted from the preoperative CT scans and are overlaid on to the live video stream transmitted from the endoscope camera during the operation, a technique known as virtual X-ray. In that way the surgeons can virtually look into the liver and locate the tumors and cysts (focus objects) and also have a basic understanding of their spatial relation with other critical structures. The current master thesis focuses on enhancing the depth and spatial perception between the focus objects and their surrounding areas when they are overlaid on to the live endoscope video stream. That is achieved by placing a cone on the position of each focus object facing the camera. The cone creates an intersection surface (cut volume) that cuts the structures that lay in it, visualizing the depth of the cut and the spatial relation between the focus object and the intersected structures. The positioning of the cones is calculated automatically according to the center points of the focus objects but the sizes of the cones are user defined with bigger sizes revealing more of the surrounding area. The rest of the structures that are not part of any cut volume are not discarded but handled in such way that still depict their spatial relation with the rest of the structures. Different rendering results are presented for a laparoscopic liver test surgery in which a plastic liver model was used. The results include different presets of the cut volumes’ characteristics. Additionally, the same technique can be applied on the 3D liver’s surface instead of the live endoscope image and provide depth and spatial information. Results from that case are also presented.

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    fulltext
  • 278.
    Felekidis, Dimitrios
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Steneteg, Peter
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Ropinski, Timo
    Visual Computing Group, Ulm University.
    Advanced visualization techniques for laparoscopic liver surgery2015Inngår i: Proceedings of SIGRAD 2015: June 1st and 2nd, Stockholm, Sweden / [ed] Christopher E. Peters, Lars Kjelldahl, Stockholm: Svenska föreningen för grafisk databehandling , 2015, s. 28-31Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In order to make it easier for the surgeons to locate tumors during a laparoscopic liver surgery, and to form a mental image of the remaining structures, the 3D models of the liver’s inner structures are extracted from a preoperative CT scan and are overlaid onto the live video stream obtained during surgery. In that way the surgeons can virtually look into the liver and locate the tumors (focus objects) and also have a basic understanding of their spatial relation with other critical structures. Within this paper, we present techniques for enhancing the spatial comprehension of the focus objects in relation to their surrounding areas, while they are overlaid onto the live endoscope video stream. To obtain an occlusion-free view while not destroying the context, we place a cone on the position of each focus object facing the camera. The cone creates an intersection surface (cut volume) that cuts the structures, visualizing the depth of the cut and the spatial relation between the focus object and the intersected structures. Furthermore, we combine this technique with several rendering approaches, which have proven to be useful for enhancing depth perception in other scenarios.

  • 279.
    Felsberg, Michael
    et al.
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.
    Forssén, Per-ErikLinköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.Sintorn, Ida-MariaDepartment of Information Technology, Division of Visual Information and Interaction, Uppsala university.Unger, JonasLinköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Image Analysis2019Konferanseproceedings (Fagfellevurdert)
    Abstract [en]

    This volume constitutes the refereed proceedings of the 21st Scandinavian Conference on Image Analysis, SCIA 2019, held in Norrköping, Sweden, in June 2019.

    The 40 revised papers presented were carefully reviewed and selected from 63 submissions. The contributions are structured in topical sections on Deep convolutional neural networks; Feature extraction and image analysis; Matching, tracking and geometry; and Medical and biomedical image analysis.

    Download (jpg)
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  • 280.
    Felsberg, Michael
    et al.
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Larsson, Fredrik
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Han, Wang
    Nanyang Technological University, China.
    Ynnerman, Anders
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Schön, Thomas
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Torch Guided Navigation2010Inngår i: Proceedings of the 2010 SSBA Symposium, 2010, s. 8-9Konferansepaper (Annet vitenskapelig)
    Abstract [en]

    A common computer vision task is navigation and mapping. Many indoor navigation tasks require depth knowledge of at, unstructured surfaces (walls, oor, ceiling). With passive illumination only, this is an ill-posed problem. Inspired by small children using a torchlight, we use a spotlight for active illumination. Using our torchlight approach, depth and orientation estimation of unstructured, at surfaces boils down to estimation of ellipse parameters. The extraction of ellipses is very robust and requires little computational effort.

  • 281.
    Felsberg, Michael
    et al.
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Larsson, Fredrik
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Wang, Han
    National University Singapore.
    Ynnerman, Anders
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Schön, Thomas
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Torchlight Navigation2011Rapport (Annet vitenskapelig)
    Abstract [en]

    A common computer vision task is navigation and mapping. Many indoor navigation tasks require depth knowledge of flat, unstructured surfaces (walls, floor, ceiling). With passive illumination only, this is an ill-posed problem. Inspired by small children using a torchlight, we use a spotlight for active illumination. Using our torchlight approach, depth and orientation estimation of unstructured, flat surfaces boils down to estimation of ellipse parameters. The extraction of ellipses is very robust and requires little computational effort.

    Fulltekst (pdf)
    FULLTEXT01
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    FULLTEXT03
  • 282.
    Felsberg, Michael
    et al.
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Larsson, Fredrik
    Linköpings universitet, Institutionen för systemteknik, Bildbehandling. Linköpings universitet, Tekniska högskolan.
    Wang, Han
    National University Singapore.
    Ynnerman, Anders
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Schön, Thomas
    Linköpings universitet, Institutionen för systemteknik, Reglerteknik. Linköpings universitet, Tekniska högskolan.
    Torchlight Navigation2010Inngår i: Proceedings of the 20th International Conferenceon Pattern Recognition, 2010, s. 302-306Konferansepaper (Fagfellevurdert)
    Abstract [en]

    A common computer vision task is navigation and mapping. Many indoor navigation tasks require depth knowledge of flat, unstructured surfaces (walls, floor, ceiling). With passive illumination only, this is an ill-posed problem. Inspired by small children using a torchlight, we use a spotlight for active illumination. Using our torchlight approach, depth and orientation estimation of unstructured, flat surfaces boils down to estimation of ellipse parameters. The extraction of ellipses is very robust and requires little computational effort.

    Fulltekst (pdf)
    FULLTEXT01
  • 283.
    Felsberg, Michael
    et al.
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.
    Öfjäll, Kristoffer
    Linköpings universitet, Institutionen för systemteknik, Datorseende. Linköpings universitet, Tekniska fakulteten.
    Lenz, Reiner
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Unbiased decoding of biologically motivated visual feature descriptors2015Inngår i: Frontiers in Robotics and AI, ISSN 2296-9144, Vol. 2, nr 20Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Visual feature descriptors are essential elements in most computer and robot vision systems. They typically lead to an abstraction of the input data, images, or video, for further processing, such as clustering and machine learning. In clustering applications, the cluster center represents the prototypical descriptor of the cluster and estimates the corresponding signal value, such as color value or dominating flow orientation, by decoding the prototypical descriptor. Machine learning applications determine the relevance of respective descriptors and a visualization of the corresponding decoded information is very useful for the analysis of the learning algorithm. Thus decoding of feature descriptors is a relevant problem, frequently addressed in recent work. Also, the human brain represents sensorimotor information at a suitable abstraction level through varying activation of neuron populations. In previous work, computational models have been derived that agree with findings of neurophysiological experiments on the represen-tation of visual information by decoding the underlying signals. However, the represented variables have a bias toward centers or boundaries of the tuning curves. Despite the fact that feature descriptors in computer vision are motivated from neuroscience, the respec-tive decoding methods have been derived largely independent. From first principles, we derive unbiased decoding schemes for biologically motivated feature descriptors with a minimum amount of redundancy and suitable invariance properties. These descriptors establish a non-parametric density estimation of the underlying stochastic process with a particular algebraic structure. Based on the resulting algebraic constraints, we show formally how the decoding problem is formulated as an unbiased maximum likelihood estimator and we derive a recurrent inverse diffusion scheme to infer the dominating mode of the distribution. These methods are evaluated in experiments, where stationary points and bias from noisy image data are compared to existing methods.

    Fulltekst (pdf)
    fulltext
  • 284.
    Flaaten, Marcus
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Efficient polygon reduction in Maya2015Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    Reducing the number of vertices in a mesh is a problem that if solved correctly can save the user a lot of time in the entire process of handling the model. Most of the solutions today are focused on reducing the mesh in one big step by running a separate application. The goal of this implementation is to bring the reduction application into the users workspace as a plugin. Many of the modellers in the various computer graphics industries use Autodesk Maya the plugins intention is to create a efficient tool which also give the modellers as much freedom as possible without the need to ever leave Mayas workspace. During the process the possible issues and solutions of creating this tool in Maya will also examined to help introduce the process of creating a tool for Maya. This plugin has the potential to improve on the existing reduction tool in Maya by giving the user more options and a more exact solution.

    Fulltekst (pdf)
    fulltext
  • 285.
    Flint, Jennifer
    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.
    Höst, Gunnar
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Schönborn, Konrad
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten.
    Virtual Worlds for Learning2020Dataset
  • 286.
    Flint, Jennifer
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Schönborn, Konrad
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Höst, Gunnar
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Lundin Palmerius, Karljohan
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Investigating an Immersive Virtual Nanoscience Simulation for Learning: Students' Interaction, Understanding, Attitudes and System Usability2014Inngår i: AERA Online Paper Repository, 2014, 2014Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Rapid nanoscientific development in a myriad of applied fields compels educational structures to develop curricular nanoknowledge for a future citizenry capable of contributing skills to a nano-workforce and in acquiring a nano-literacy. This study investigated ten Swedish upper-secondary students' interactions with a virtual reality nanoworld and sought to illuminate: 1) how students link to and support their understanding of prior science knowledge, 2) students' attitudes towards the benefits and risks of nanotechnology, and 3) the usability of the system. Analyzed videotaped and written data elicited cognitive mechanisms underlying interaction with the virtual reality environment for promoting understanding, the influence of the interactive experience on students' attitudes to nanophenomena, and system features that could be applied in real science classrooms.

  • 287.
    Flügge, Josefine
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Liljegren, Gustaf
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Användarcentrerad Guide för Hållbart Jordbruk - Utformning av ett gränssnitt för utveckling av kvävegödslingsstrategier2020Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [sv]

    I detta examensarbete beskrivs processen för att designa, implementera och utvärdera ett webbgränssnitt som syftar till att hjälpa lantbrukare att ta fram en skräddarsydd kvävegödslingsstrategi. Målet med examensarbetet var att utforska hur ett sådant verktyg kan bli implementerat och brukas av målgruppen. I synnerhet granskades vilken data som är meningsfull för att ta beslut om kvävegödsling, hur gränssnittet kan implementeras för att vägleda användaren till ett beslut samt hur verktyget kan uppmana till mer effektiv växtodling.

    Fulltekst (pdf)
    fulltext
  • 288.
    Fogelholm, Jesper
    et al.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Henriksen, Rie
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Höglund, Andrey
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Huq, N.
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Johnsson, M.
    The Roslin Institute and Royal (Dick) School of Veterinary Studies, The University of Edinburgh, Midlothian, Scotland, United Kingdom, Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden.
    Lenz, Reiner
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska fakulteten. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Jensen, Per
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    Wright, Dominic
    Linköpings universitet, Institutionen för fysik, kemi och biologi, Biologi. Linköpings universitet, Tekniska fakulteten.
    CREBBP and WDR 24 Identified as Candidate Genes for Quantitative Variation in Red-Brown Plumage Colouration in the Chicken2020Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 10, nr 1, artikkel-id 1161Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Plumage colouration in birds is important for a plethora of reasons, ranging from camouflage, sexual signalling, and species recognition. The genes underlying colour variation have been vital in understanding how genes can affect a phenotype. Multiple genes have been identified that affect plumage variation, but research has principally focused on major-effect genes (such as those causing albinism, barring, and the like), rather than the smaller effect modifier loci that more subtly influence colour. By utilising a domestic × wild advanced intercross with a combination of classical QTL mapping of red colouration as a quantitative trait and a targeted genetical genomics approach, we have identified five separate candidate genes (CREBBP, WDR24, ARL8A, PHLDA3, LAD1) that putatively influence quantitative variation in red-brown colouration in chickens. By treating colour as a quantitative rather than qualitative trait, we have identified both QTL and genes of small effect. Such small effect loci are potentially far more prevalent in wild populations, and can therefore potentially be highly relevant to colour evolution.

    Fulltekst (pdf)
    fulltext
  • 289.
    Forsberg, Daniel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Sectra AB, Linköping, Sweden.
    Lindblom, Maria
    Linköpings universitet, Institutionen för medicin och hälsa. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Diagnostikcentrum, Röntgenkliniken i Linköping.
    Quick, Petter
    Linköpings universitet, Institutionen för medicin och hälsa. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Diagnostikcentrum, Röntgenkliniken i Linköping. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Gauffin, Håkan
    Linköpings universitet, Institutionen för klinisk och experimentell medicin, Avdelningen för kliniska vetenskaper. Linköpings universitet, Medicinska fakulteten. Region Östergötland, Centrum för kirurgi, ortopedi och cancervård, Ortopedkliniken i Linköping.
    Quantitative analysis of the patellofemoral motion pattern using semi-automatic processing of 4D CT data2016Inngår i: International Journal of Computer Assisted Radiology and Surgery, ISSN 1861-6410, E-ISSN 1861-6429, Vol. 11, nr 9, s. 1731-1741Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To present a semi-automatic method with minimal user interaction for quantitative analysis of the patellofemoral motion pattern. 4D CT data capturing the patellofemoral motion pattern of a continuous flexion and extension were collected for five patients prone to patellar luxation both pre- and post-surgically. For the proposed method, an observer would place landmarks in a single 3D volume, which then are automatically propagated to the other volumes in a time sequence. From the landmarks in each volume, the measures patellar displacement, patellar tilt and angle between femur and tibia were computed. Evaluation of the observer variability showed the proposed semi-automatic method to be favorable over a fully manual counterpart, with an observer variability of approximately 1.5 for the angle between femur and tibia, 1.5 mm for the patellar displacement, and 4.0-5.0 for the patellar tilt. The proposed method showed that surgery reduced the patellar displacement and tilt at maximum extension with approximately 10-15 mm and 15-20 for three patients but with less evident differences for two of the patients. A semi-automatic method suitable for quantification of the patellofemoral motion pattern as captured by 4D CT data has been presented. Its observer variability is on par with that of other methods but with the distinct advantage to support continuous motions during the image acquisition.

  • 290.
    Forsberg, Daniel
    et al.
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Sectra, Linköping, Sweden .
    Lundström, Claes
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan. Sectra, Linköping, Sweden .
    Andersson, Mats
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Knutsson, Hans
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Eigenspine: Eigenvector Analysis of Spinal Deformities in Idiopathic Scoliosis2014Inngår i: Computational Methods and Clinical Applications for Spine Imaging: Proceedings of the Workshop held at the 16th International Conference on Medical Image Computing and Computer Assisted Intervention, September 22-26, 2013, Nagoya, Japan / [ed] Jianhua Yao,Tobias Klinder, Shuo Li, Springer, 2014, Vol. 17, s. 123-134Konferansepaper (Fagfellevurdert)
    Abstract [en]

    In this paper, we propose the concept of eigenspine, a data analysis schemeuseful for quantifying the linear correlation between different measures relevant fordescribing spinal deformities associated with spinal diseases, such as idiopathic scoliosis.The proposed concept builds upon the use of principal component analysis(PCA) and canonical correlation analysis (CCA), where PCA is used to reduce thenumber of dimensions in the measurement space, thereby providing a regularizationof the measurements, and where CCA is used to determine the linear dependence betweenpair-wise combinations of the different measures. To demonstrate the usefulnessof the eigenspine concept, the measures describing position and rotation of thelumbar and the thoracic vertebrae of 22 patients suffering from idiopathic scoliosiswere analyzed. The analysis showed that the strongest linear relationship is foundbetween the anterior-posterior displacement and the sagittal rotation of the vertebrae,and that a somewhat weaker but still strong correlation is found between thelateral displacement and the frontal rotation of the vertebrae. These results are wellin-line with the general understanding of idiopathic scoliosis. Noteworthy though isthat the obtained results from the analysis further proposes axial vertebral rotationas a differentiating measure when characterizing idiopathic scoliosis. Apart fromanalyzing pair-wise linear correlations between different measures, the method isbelieved to be suitable for finding a maximally descriptive low-dimensional combinationof measures describing spinal deformities in idiopathic scoliosis.

    Fulltekst (pdf)
    fulltext
  • 291.
    Forsberg, Daniel
    et al.
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Lundström, Claes
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Andersson, Mats
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Knutsson, Hans
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Model-based registration for assessment of spinal deformities in idiopathic scoliosis2014Inngår i: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 59, nr 2, s. 311-326Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Detailed analysis of spinal deformity is important within orthopaedic healthcare, in particular for assessment of idiopathic scoliosis. This paper addresses this challenge by proposing an image analysis method, capable of providing a full three-dimensional spine characterization. The proposed method is based on the registration of a highly detailed spine model to image data from computed tomography. The registration process provides an accurate segmentation of each individual vertebra and the ability to derive various measures describing the spinal deformity. The derived measures are estimated from landmarks attached to the spine model and transferred to the patient data according to the registration result. Evaluation of the method provides an average point-to-surface error of 0.9 mm ± 0.9 (comparing segmentations), and an average target registration error of 2.3 mm ± 1.7 (comparing landmarks). Comparing automatic and manual measurements of axial vertebral rotation provides a mean absolute difference of 2.5° ± 1.8, which is on a par with other computerized methods for assessing axial vertebral rotation. A significant advantage of our method, compared to other computerized methods for rotational measurements, is that it does not rely on vertebral symmetry for computing the rotational measures. The proposed method is fully automatic and computationally efficient, only requiring three to four minutes to process an entire image volume covering vertebrae L5 to T1. Given the use of landmarks, the method can be readily adapted to estimate other measures describing a spinal deformity by changing the set of employed landmarks. In addition, the method has the potential to be utilized for accurate segmentations of the vertebrae in routine computed tomography examinations, given the relatively low point-to-surface error.

    Fulltekst (pdf)
    Model-based registration for assessment of spinal deformities in idiopathic scoliosis
  • 292.
    Forsberg, Daniel
    et al.
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan.
    Lundström, Claes
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Andersson, Mats
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan.
    Vavruch, Ludvig
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för klinisk och experimentell medicin, Neurokirurgi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Ortopedkliniken i Linköping.
    Tropp, Hans
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för klinisk och experimentell medicin, Ortopedi. Linköpings universitet, Hälsouniversitetet. Östergötlands Läns Landsting, Centrum för kirurgi, ortopedi och cancervård, Ortopedkliniken i Linköping.
    Knutsson, Hans
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Hälsouniversitetet.
    Fully automatic measurements of axial vertebral rotation for assessment of spinal deformity in idiopathic scoliosis2013Inngår i: Physics in Medicine and Biology, ISSN 0031-9155, E-ISSN 1361-6560, Vol. 58, nr 6, s. 1775-1787Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Reliable measurements of spinal deformities in idiopathic scoliosis are vital, since they are used for assessing the degree of scoliosis, deciding upon treatment and monitoring the progression of the disease. However, commonly used two dimensional methods (e.g. the Cobb angle) do not fully capture the three dimensional deformity at hand in scoliosis, of which axial vertebral rotation (AVR) is considered to be of great importance. There are manual methods for measuring the AVR, but they are often time-consuming and related with a high intra- and inter-observer variability. In this paper, we present a fully automatic method for estimating the AVR in images from computed tomography. The proposed method is evaluated on four scoliotic patients with 17 vertebrae each and compared with manual measurements performed by three observers using the standard method by Aaro-Dahlborn. The comparison shows that the difference in measured AVR between automatic and manual measurements are on the same level as the inter-observer difference. This is further supported by a high intraclass correlation coefficient (0.971-0.979), obtained when comparing the automatic measurements with the manual measurements of each observer. Hence, the provided results and the computational performance, only requiring approximately 10 to 15 s for processing an entire volume, demonstrate the potential clinical value of the proposed method.

    Fulltekst (pdf)
    fulltext
  • 293.
    Forsberg, Daniel
    et al.
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Sectra, Linköping, Sweden.
    Lundström, Claes
    Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan. Sectra, Linköping, Sweden.
    Knutsson, Hans
    Linköpings universitet, Institutionen för medicinsk teknik, Medicinsk informatik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV.
    Eigenspine: Computing the Correlation between Measures Describing Vertebral Pose for Patients with Adolescent Idiopathic Scoliosis2014Inngår i: Computerized Medical Imaging and Graphics, ISSN 0895-6111, E-ISSN 1879-0771, Vol. 38, nr 7, s. 549-557Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper describes the concept of eigenspine, a concept applicable for determining the correlation between pair-wise combinationsof measures useful for describing the three-dimensional spinal deformities associated with adolescent idiopathic scoliosis. Theproposed data analysis scheme is based upon the use of principal component analysis (PCA) and canonical correlation analysis(CCA). PCA is employed to reduce the dimensionality of the data space, thereby providing a regularization of the measurements,and CCA is employed to determine the linear dependence between pair-wise combinations of different measures. The usefulness ofthe eigenspine concept is demonstrated by analyzing the position and the rotation of all lumbar and thoracic vertebrae as obtainedfrom 46 patients suffering from adolescent idiopathic scoliosis. The analysis showed that the strongest linear relationship is foundbetween the lateral displacement and the coronal rotation of the vertebrae, and that a somewhat weaker but still strong correlationis found between the coronal rotation and the axial rotation of the vertebrae. These results are well in-line with the generalunderstanding of idiopathic scoliosis. Noteworthy though is that the correlation between the anterior-posterior displacement and thesagittal rotation was not as strong as expected and that the obtained results further indicate the need for including the axial vertebralrotation as a measure when characterizing different types of idiopathic scoliosis. Apart from analyzing pair-wise correlationsbetween different measures, the method is believed to be suitable for finding a maximally descriptive low-dimensional combinationof measures describing spinal deformities in idiopathic scoliosis.

    Fulltekst (pdf)
    fulltext
  • 294.
    Forsberg, Daniel
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan. Linköpings universitet, Centrum för medicinsk bildvetenskap och visualisering, CMIV. Sectra, Linköping, Sweden.
    Monsef, Nastaran
    Region Östergötland, Diagnostikcentrum, Klinisk patologi och klinisk genetik. Linköpings universitet, Institutionen för teknik och naturvetenskap. Linköpings universitet, Tekniska högskolan.
    Evaluating Cell Nuclei Segmentation for Use on Whole-Slide Images in Lung Cytology2014Inngår i: 2014 22nd International Conference on Pattern Recognition (ICPR), IEEE Computer Society, 2014, s. 3380-3385Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper presents results from an evaluation of three previously presented methods for segmentation of cell nuclei in lung cytology samples scanned by whole-slide scanners. Whole-slide images from seven cases of endobronchial ultrasound-guided transbronchial needle aspiration samples were used for extracting a number of regions of interest, in which approximately 2700 cell nuclei were manually segmented to form the ground truth. The segmented cells included benign bronchial epithelium, lymphocytes, granulocytes, histiocytes and malignant epithelial cells. The best results were obtained with a method based upon adaptive thresholding and an added step of clustering for distinguishing between cytoplasm and cell nuclei. This method achieved a mean DICE-score of 0.81 and a sensitivity and specificity of 0.88 and 0.81 respectively. In addition, this method was by far the fastest method, with a mean processing time of 7.8 s per image (2048 x 2048 pixels per image). By further improvements, such as lowering the false positive rate and using parallel computing hardware, this method has the potential to form the first building block in a system for computerized screening of whole-slide images in lung cytology.

  • 295.
    Forsell, Camilla
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    A Guide to Scientific Evaluation in Information Visualization2010Inngår i: 14th International Conference Information Visualization IV 2010, 2010, s. 162-169Konferansepaper (Fagfellevurdert)
    Abstract [en]

    This paper addresses some fundamental and practical issues that should be considered when pursuing evaluation studies in Information Visualization. The main focus is on quantitative experimental research but the general information applies to all kinds of studies. The purpose is to increase awareness of what constitutes a sound scientific approach to evaluation and to point out common pitfalls and mistakes during the phases of such study. These phases cover how to plan, design, conduct and analyse the outcome of an evaluation and finally how to report in a way that enhances readability, provides details relevant to the outcome and that allows replication. The paper could be used as a guide when conducting evaluation and it could also be helpful when reviewing publications since the same rules apply.

  • 296.
    Forsell, Camilla
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    An Introduction and Guide to Evaluation of Visualization Techniques Through User Studies2014Inngår i: Handbook of human centric visualization / [ed] Weidong Huang, New York: Springer, 2014, s. 285-313Kapittel i bok, del av antologi (Fagfellevurdert)
  • 297.
    Forsell, Camilla
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Cooper, Matthew
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Questionnaires for evaluation in information visualization2012Inngår i: BELIV '12 Proceedings of the 2012 BELIV Workshop: Beyond Time and Errors - Novel Evaluation Methods for Visualization, New York: ACM Press, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

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

  • 298.
    Forsell, Camilla
    et al.
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Johansson, Jimmy
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    An Heuristic Set for Evaluation in Information Visualization2010Inngår i: Advanced Visual Interfaces, AVI10, New York, USA: ACM press , 2010, s. 199-206Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Evaluation is a key research challenge within the international Information Visualization (InfoVis) community, and Heuristic Evaluation is one recognized method. Various sets of heuristics have been proposed but there remains no consensus as to which heuristics are most useful for addressing aspects specific to the complex interactive visual displays used in modern InfoVis systems. This paper presents a first effort to empirically determine a new set of such general heuristics tailored for Heuristic Evaluation of common and important usability problems in InfoVis techniques. Participants in the study rated how well a total of 63 heuristics from 6 earlier published heuristic sets could explain a collection of 74 usability problems derived from earlier InfoVis evaluations. The results were used to synthesize 10 heuristics that, as a set, provided the highest explanatory coverage. The paper also stresses the challenges for future research to validate and further improve upon this set.

  • 299.
    Forsling Parborg, Emma
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Towards replacing the remote control with commodity smart-phones through evaluation of interaction techniques enabling television service navigation2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    The aim for this project was to develop an application that would be compatible with set-top boxes, or other browser based applications, and re-search what interaction techniques that could be considered a viable substitute for a the traditional remote controller without requiring the visual attention of the viewer User test was also performed in the interest of broadly evaluating the different interaction techniques used in the application, and how the UI itself, including non visual feedback from both the sender and receiver side is perceived.

    Fulltekst (pdf)
    Towards replacing the remote control with commodity smart-phones through evaluation of interaction techniques enabling television service navigation
  • 300.
    Forsman, Isabelle
    Linköpings universitet, Institutionen för teknik och naturvetenskap, Medie- och Informationsteknik. Linköpings universitet, Tekniska högskolan.
    Automatic LOD selection2017Independent thesis Advanced level (degree of Master (Two Years)), 20 poäng / 30 hpOppgave
    Abstract [en]

    In this paper a method to automatically generate transition distances for LOD, improving image stability and performance is presented. Three different methods were tested all measuring the change between two level of details using the spatial frequency. The methods were implemented as an optional pre-processing step in order to determine the transition distances from multiple view directions. During run-time both view direction based selection and the furthest distance for each direction was tested in order to measure the performance and image stability. The work was implemented in the Frostbite game engine and tested using data from DICE. The result is a method that generates transition distances by calculating the spatial frequency of the exclusive or comparison between the silhouette of a ground truth mesh and each level of detail. The transition distances generated using the automatic LOD selection tool was evaluated using visual empirical tests and performance measurements comparing the performance of a scene using automatic generated distances and manually selected distances. The tests shows that the resulting method produces good transition distances for meshes where the reduction is visible in the mesh silhouette. The values might need a bit of tweaking in order to account for other image artifacts than silhouette changes but provide a good guidance to the artists.

    Fulltekst (pdf)
    Automatic LOD selection
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