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  • 1.
    Arndt, Sebastian
    et al.
    Technische Universitat Berlin, Berlin, Germany.
    Brunnström, Kjell
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. Acreo Swedish ICT.
    Cheng, Eva
    Royal Melbourne Institute of Technology (RMIT), Melbourne, Australia.
    Engelke, Ulrich
    Commonwealth Scientific and Industrial Research Organisation (CSIRO), Hobart, Australia.
    Möller, Sebastian
    Technische Universitat Berlin, Berlin, Germany.
    Antons, Jan-Niklas
    Technische Universitat Berlin, Berlin, Germany.
    Review on using physiology in quality of experience2016In: Human Vision and Electronic Imaging 2016, HVEI 2016, The Society for Imaging Science and Technology, 2016, p. 197-205Conference paper (Refereed)
    Abstract [en]

    In the area of Quality of Experience (QoE), one challenge is to design test methodologies in order to evaluate the perceived quality of multimedia content delivered through technical sys-tems. Traditionally, this evaluation is done using subjective opinion tests. However, sometimes it is difficult for observers to communicate the experienced quality through the given scale. Fur-thermore. those tests do not give insights into how the user is reacting on an internal physiological level. To overcome these issues, one approach is to use physiological measures, in order to derive a direct non-verbal response of the recipient. In this paper, we review studies that have been performed in the domain of QoE using physiological measures and we look into current activities in standardization bodies. We present challenges this research faces. and give an overview on what researchers should be aware of when they want to start working in this research area.

  • 2.
    Brunnström, Kjell
    et al.
    Acreo AB, Kista, Sweden.
    Sedano, Iñigo
    Tecnalia Research & Innovation, Bilbao, Spain.
    Wang, Kun
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Barkowsky, Markus
    IRCCyN, Nantes; France.
    Kihl, Maria
    Lund University.
    Andrén, Börje
    Acreo AB, Kista, Sweden.
    Le Callet, Patrick
    IRCCyN, Nantes; France.
    Sjöström, Mårten
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Aurelius, Andreas
    Acreo AB, Kista, Sweden.
    2D no-reference video quality model development and 3D video transmission quality2012In: Proceedings of the Sixth International Workshop on Video Processing and Quality Metrics for Consumer Electronics VPQM-2012, 2012Conference paper (Other academic)
    Abstract [en]

    This presentation will target two different topics in video quality assessment. First, we discuss 2D no-reference video quality model development. Further, we discuss how to find suitable quality for 3D video transmission. No-reference metrics are the only practical option for monitoring of 2D video quality in live networks. In order to decrease the development time, it might be possible to use full-reference metrics for this purpose. In this work, we have evaluated six full-reference objective metrics in three different databases. We show statistically that VQM performs the best. Further, we use these results to develop a lightweight no-reference model. We have also investigated users' experience of stereoscopic 3D video quality by performing the rating of two subjective assessment datasets, targeting in one dataset efficient transmission in the transmission error free case and error concealment in the other. Among other results, it was shown that, based on the same level of quality of experience, spatial down-sampling may lead to better bitrate efficiency while temporal down-sampling will be worse. When network impairments occur, traditional error 2D concealment methods need to be reinvestigated as they were outperformed switching to 2D presentation.

  • 3.
    Brunnström, Kjell
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. Acreo Swedish ICT AB.
    Wang, Kun
    Acreo Swedish ICT AB.
    Tavakoli, Samira
    Universidad Politécnica de Madrid, Spain.
    Andrén, Börje
    Acreo Swedish ICT AB.
    Symptoms analysis of 3D TV viewing based on Simulator Sickness Questionnaires2017In: Quality and User Experience, ISSN 2366-0147, Vol. 2, no 1Article in journal (Refereed)
    Abstract [en]

    Stereoscopic 3D TV viewing puts different visual demands on the viewer compared to 2D TV viewing. Previous research has reported on viewers' fatigue and discomfort and other negative effects. This study is to investigate further how severe and what symptoms may arise from somewhat longish 3D TV viewing.

    The MPEG 3DV project is working on the next-generation video encoding standard and in this process, MPEG issued a call for proposal of encoding algorithms. To evaluate these algorithms a large scale subjective test was performed involving Laboratories all over the world[1, 2]. For the participating Labs, it was optional to administer a slightly modified Simulator Sickness Questionnaire (SSQ) before and after the test. One of the SSQ data sets described in this article is coming from this study. The SSQ data from the MPEG test is the largest data set in this study and also contains the longest viewing times. Along with the SSQ data from the MPEG test, we have also collected questionnaire data in three other 3D TV studies. We did two on the same 3D TV (passive film pattern retarder) as in the MPEG test, and one was using a projector system. As comparison SSQ data from a 2D video quality experiment is also presented. 

    This investigation shows a statistically significant increase in symptoms after viewing 3D TV primarily related to the visual or Oculomotor system. Surprisingly, 3D video viewing using projectors did not show this effect.

  • 4.
    Dima, Elijs
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology.
    Sjöström, Mårten
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology.
    Olsson, Roger
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Systems and Technology.
    Modeling Depth Uncertainty of Desynchronized Multi-Camera Systems2017In: 2017 International Conference on 3D Immersion (IC3D), IEEE, 2017Conference paper (Refereed)
    Abstract [en]

    Accurately recording motion from multiple perspectives is relevant for recording and processing immersive multi-media and virtual reality content. However, synchronization errors between multiple cameras limit the precision of scene depth reconstruction and rendering. In order to quantify this limit, a relation between camera de-synchronization, camera parameters, and scene element motion has to be identified. In this paper, a parametric ray model describing depth uncertainty is derived and adapted for the pinhole camera model. A two-camera scenario is simulated to investigate the model behavior and how camera synchronization delay, scene element speed, and camera positions affect the system's depth uncertainty. Results reveal a linear relation between synchronization error, element speed, and depth uncertainty. View convergence is shown to affect mean depth uncertainty up to a factor of 10. Results also show that depth uncertainty must be assessed on the full set of camera rays instead of a central subset.

  • 5.
    Hallberg, Peter
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Digital reproduktion av analogt inspelad låt: Går det att höra vilken låt som gjort på vilket sätt?2018Independent thesis Basic level (university diploma), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    I denna uppsats undersöks hur väl man med en enkel hemmastudio och dagens tekniskt välutvecklade digitala plugins kan återskapa soundet från en påkostad analog produktion. En nyinspelning, med den analoga versionen som referens, görs i en hemmastudio. Vilka likheter och skillnader kan lyssnaren identifiera och vilken låt är gjord på vilket sätt?

    En testgrupp bestående av 15 personer i varierad ålder, kön och musikalisk identitet fick lyssna på båda versionerna varpå de sedan dokumenterade sina intryck i en enkät. Det visade sig att de allra flesta kunde peka ut vilken produktion som gjorts på vilket sätt med motivationen att den analoga kändes bättre mixad och balanserad. Arbete visar att projektet i slutändan blev för stort för att ge några klara svar. Resultatet visar att jag personligen, med den kunskap jag besitter och inom den tidsram som tagits fram, inte fullt ut kan återskapa soundet. Dock insinuerar jag ändå att det kan vara möjligt. En annan låt, en annan producent och/eller längre tid på återskapandet är några exempel på faktorer som kanske skulle ledat till annat utfall. En mer specifik frågeställning med färre möjligheter till felsteg skulle med stor sannolikhet också förenklat arbetsprocessen och slutresultatet.

  • 6.
    Muddala, Suryanarayana Murthy
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    Sjöström, Mårten
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    Olsson, Roger
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    Depth-Based Inpainting For Disocclusion Filling2014In: 3DTV-Conference, IEEE Computer Society, 2014, p. Art. no. 6874752-Conference paper (Refereed)
    Abstract [en]

    Depth-based inpainting methods can solve disocclusion problems occurring in depth-image-based rendering. However, inpainting in this context suffers from artifacts along foreground objects due to foreground pixels in the patch matching. In this paper, we address the disocclusion problem by a refined depth-based inpainting method. The novelty is in classifying the foreground and background by using available local depth information. Thereby, the foreground information is excluded from both the source region and the target patch. In the proposed inpainting method, the local depth constraints imply inpainting only the background data and preserving the foreground object boundaries. The results from the proposed method are compared with those from the state-of-the art inpainting methods. The experimental results demonstrate improved objective quality and a better visual quality along the object boundaries.

  • 7.
    Namedanian, Mahziar
    et al.
    Department of Science and Technology, Linköping University, Norrköping, Sweden .
    Gustafsson Coppel, Ludovic
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Neuman, Magnus
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Gooran, Sasan
    Department of Science and Technology, Linköping University, Norrköping, Sweden .
    Edström, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Kolseth, Petter
    Nsieme Consulting, Sweden .
    Koh, Wei
    Analysis of Optical and Physical Dot Gain by Microscale Image Histogram and Modulation Transfer Functions2013In: Journal of Imaging Science and Technology, ISSN 1062-3701, E-ISSN 1943-3522, Vol. 57, no 2, p. 020504-1-020504-5Article in journal (Refereed)
    Abstract [en]

    The color of a print is affected by ink spreading and lateral light scattering in the substrate, making printed dots appear larger. Characterization of physical and optical dot gain is crucial for the graphic arts and paper industries. We propose a novel approach to separate physical from optical dot gain by use of a high-resolution camera. This approach is based on the histogram of microscale images captured by the camera. Having determined the actual physical dot shape, we estimate the modulation transfer function (MTF) of the paper substrate. The proposed method is validated by comparing the estimated MTF of 11 offset printed coated papers to the MTF obtained from the unprinted papers using measured and Monte Carlo simulated edge responses.

  • 8.
    Olsson, Roger
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Adhikarla, Vamsi Kiran
    Blekinge Institute of Technology, Karlskrona, Sweden.
    Schwarz, Sebastian
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Sjöström, Mårten
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Converting conventional stereo pairs to multi-view sequences using morphing2012In: Proceedings of SPIE - The International Society for Optical Engineering, SPIE - International Society for Optical Engineering, 2012, p. Art. no. 828828-Conference paper (Refereed)
    Abstract [en]

    Autostereoscopic multi view displays require multiple views of a scene to provide motion parallax. When an observer changes viewing angle different stereoscopic pairs are perceived. This allows new perspectives of the scene to be seen giving a more realistic 3D experience. However, capturing arbitrary number of views is at best cumbersome, and in some occasions impossible. Conventional stereo video (CSV) operates on two video signals captured using two cameras at two different perspectives. Generation and transmission of two views is more feasible than that of multiple views. It would be more efficient if multiple views required by an autostereoscopic display can be synthesized from these sparse set of views. This paper addresses the conversion of stereoscopic video to multiview video using the video effect morphing. Different morphing algorithms are implemented and evaluated. Contrary to traditional conversion methods, these algorithms disregard the physical depth explicitly and instead generate intermediate views using sparse sets of correspondence features and image morphing. A novel morphing algorithm is also presented that uses scale invariant feature transform (SIFT) and segmentation to construct robust correspondences features and qualitative intermediate views. All algorithms are evaluated on a subjective and objective basis and the comparison results are presented.

  • 9.
    Rahaman, G M Atiqur
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Norberg, Ole
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    Edström, Per
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Natural Sciences.
    The effect of media interactions in predicting spectral reflectance by color prediction models2013Conference paper (Refereed)
  • 10.
    Sjöström, Mårten
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Olsson, Roger
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    Dalin, Rolf
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information Technology and Media.
    A digital 3D signage system and its effect on customer behavior2011In: The International Conference on 3D Imaging (IC3D), IEEE conference proceedings, 2011, article id 6584378Conference paper (Refereed)
    Abstract [en]

    The use of digital signs simplifies distribution. Importantly, it draws more attention than static signs. A way to increase attention is to add an experienced depth. The paper discusses possible alternatives for extending an existing digital signage system to display stereoscopic 3D contents, comparing a decentralized distribution solution and a centralized solution. A functional prototype system was implemented. A new 3D player was developed to render views from different formats. The implemented system was used to study customer behavior when exposed to digital stereoscopic 3D signage in a direct sales situation. The proportion of sales of selected products related to the total number of sold products varied approximately equally before and during tests. An interview study suggests that the sign did not interact with customer decisions: customers were lost at different stages in this series of steps, among others the sign placement.

  • 11.
    Søgaard, Jacob
    et al.
    Technical University of Denmark, Lyngby, Denmark.
    Tavakolf, Samira
    Universidad Politecnica de Madrid, Madrid, Spain.
    Brunnström, Kjell
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. Acreo Swedish ICT AB.
    Garcia, Narciso
    Universidad Politecnica de Madrid, Madrid, Spain.
    Subjective analysis and objective characterization of adaptive bitrate videos2016In: Human Vision and Electronic Imaging 2016, HVEI 2016, The Society for Imaging Science and Technology, 2016, p. 55-63Conference paper (Refereed)
    Abstract [en]

    The HTTP Adaptive Streaming (HAS) technology allows video service providers to improve the network utilization and thereby increasing the end-users' Quality of Experience (QoE). This has made HAS a widely used approach for audiovisual delivery There are several previous studies aiming to identify the factors influencing on subjective QoE of adaptation events. However, adapting the video quality typically lasts m a time scale much longer than what current standardized subjective testing methods are designed for. thus making the full matrix design of the experiment on an event level hard to achieve. In this study, we investigated the overall subjective QoE of 6 minutes long video sequences containing different sequential adaptation events. This was compared to a dataset from our previous work performed to evaluate the individual adaptation events. We could then derive a relationship between the overall mean opinion score (MOS) and the MOS from shorter sequences. The aforementioned empirical dataset has proven to be very challenging in terms of video quality assessment test design, thus deriving a conclusive outcome about the influence of different parameters have been difficult. The second contribution of this study is considering how objective characterizations of adapted videos can improve the understanding of the subjective ratings.

  • 12.
    Tavakoli, Samira
    et al.
    Universidad Politécnicade Madrid, Spain.
    Brunnström, Kjell
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. Acreo Swedish ICT AB, Sweden.
    Gutiérrez, Jesús
    Universidad Politécnicade Madrid, Spain.
    Quality of Experience of adaptive video streaming: Investigation in service parameters and subjective quality assessment methodology2015In: Signal processing. Image communication, ISSN 0923-5965, E-ISSN 1879-2677, Vol. 39, p. 432-443Article in journal (Refereed)
    Abstract [en]

    The usage of HTTP adaptive streaming (HAS) has become widely spread in multimedia services. Because it allows the service providers to improve the network resource utilization and user's Quality of Experience (QoE). Using this technology, the video playback interruption is reduced since the network and server status in addition to capability of user device, all are taken into account by HAS client to adapt the quality to the current condition. Adaptation can be done using different strategies. In order to provide optimal QoE, the perceptual impact of adaptation strategies from point of view of the user should be studied. However, the time-varying video quality due to the adaptation which usually takes place in a long interval introduces a new type of impairment making the subjective evaluation of adaptive streaming system challenging. The contribution of this paper is two-fold: first, it investigates the testing methodology to evaluate HAS QoE by comparing the subjective experimental outcomes obtained from ACR standardized method and a semi-continuous method developed to evaluate the long sequences. In addition, influence of using audiovisual stimuli to evaluate the video-related impairment is inquired. Second, impact of some of the adaptation technical factors including the quality switching amplitude and chunk size in combination with high range of commercial content type is investigated. The results of this study provide a good insight toward achieving appropriate testing method to evaluate HAS QoE, in addition to designing switching strategies with optimal visual quality.

  • 13.
    Wang, Kun
    et al.
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. Dept. of NetLab: Visual Media Quality, Swedish ICT-Acreo AB, Sweden .
    Brunnström, Kjell
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems. Dept. of NetLab: Visual Media Quality, Swedish ICT-Acreo AB, Sweden .
    Barkowsky, M.
    Dept. of Image and Video Communication, IRCCyN, University of Nantes, France .
    Urvoy, M.
    Dept. of Image and Video Communication, IRCCyN, University of Nantes, France .
    Sjöström, Mårten
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    Le Callet, P.
    Dept. of Image and Video Communication, IRCCyN, University of Nantes, France .
    Tourancheau, Sylvain
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Information and Communication systems.
    Andren, B.
    Dept. of NetLab: Visual Media Quality, Swedish ICT-Acreo AB, Sweden .
    Stereoscopic 3D video coding quality evaluation with 2D objective metrics2013In: Proceedings of SPIE - The International Society for Optical Engineering, 2013, p. Art. no. 86481L-Conference paper (Refereed)
    Abstract [en]

    The 3D video quality is of highest importance for the adoption of a new technology from a user's point of view. In this paper we evaluated the impact of coding artefacts on stereoscopic 3D video quality by making use of several existing full reference 2D objective metrics. We analyzed the performance of objective metrics by comparing to the results of subjective experiment. The results show that pixel based Visual Information Fidelity metrics fits subjective data the best. The 2D stereoscopic video quality seems to have dominant impact on the coding artefacts impaired stereoscopic videos.

  • 14.
    zhang, zhennan
    Mid Sweden University, Faculty of Science, Technology and Media, Department of Electronics Design.
    Camera Node for Conical Volumetric Surveillance2014Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Generally  cameras  are  used  for  area  based  surveillance,  but  with  advancement  in  technology, cameras  can  be  employed  for wide  area  space  surveillance  (volumetric space surveillance). The volumetric systems require a number of cameras in order to cover a large area. Single panoramic cameras  do  not  provide  required  functionality  for  wide  area  space  surveillance  and Pan-Tile-Zoom (PTZ) cameras do not either cover wide areas.   To  meet  this challenge,  we  propose  a  cost  effective smart volumetric  surveillance system  which utilizes smaller number of cameras in order to provide a coverage of 360 degree. A test case used for this system includes detection of birds in the wind farms. The proposed approach provides a solution  for recording/preventing collision  of  birds  with  wind turbine. To  realize  the  system, a model is developed with two camera nodes. This model provides a 360 degree conical volumetric space coverage. The  system is  utilizing  a  servo  motor  with  capability  of  changing  speed  and arduino  embedded  platform for  controlling  different  functionality. After  triggering  the  camera nodes from arduino, software perform the image analysis.  This  cost  effective  and  wide  area  surveillance  system  consumes at  least half lower  power as compared  to traditional  linear  systems with  eight  cameras. It  is  worth  noting  that  the system provides  conical  shaped  area coverage  of  200  square  meters  with  height ranging  from approximately 40 to 100 meters. The system would capture images in raw format in local storage and  the test  results  show  that  saving  images  with  PNG  format  requires a small  memory  size  as compared  to BMP  and TIFF.    Experiment  results  indicate  that  surveillance  system  can  be effectively employed for detecting birds in opening places.

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