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Suche nach „[Barkowsky] [Marcus]“ hat 114 Publikationen gefunden
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    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Marcus Barkowsky, M. Blestel, M. Carnec, A. Ksentini, P. Le Callet, G. Madec, R. Monnier, J. Nezan, R. Pepion, Y. Pitrey, J-F Travers, M. Raulet, A. Untersee

    An Overview of the SVC4QoE project

    Mobile Multimedia Communications, vol. 77

    2012

    ISBN: 978-3-642-35154-9

    Abstract anzeigen

    The aim of this paper is to give an overview of the SVC4QoE project which purpose is to use Scalable Video Coding (SVC) to optimize video transmission in terms of Quality of Experience over DVB-T2 channels. The originality of this project is to consider the influence of the whole chain of processing and delivery performed on the video data in terms of user-perceived quality. The encoding process, as well as transmission, decoding and display are included in the optimization process. Particularly, the multi-layer structure of SVC is to be exploited to circumvent alterations of the video related to transmission on error-prone networks. Combining SVC with QoE thus provides a way to reduce network operating costs, while increasing the quality from the user’s point of view. Several innovations are also to be mentioned, such as the use of a real-time open-source SVC decoder, evaluation of visual quality through subjective quality assessment tests, transmission and synchronization of SVC layers on the receiver’s side, and development and integration of an end-to-end DVB-T2 chain which implements the multi-PLP (Physical Layer Pipes) functionality in an SVC context.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    M. Pinson, L. Janowski, R. Pepion, Q. Huynh-Thu, C. Schmidmer, P. Corriveau, A. Younkin, P. Le Callet, Marcus Barkowsky, W. Ingram

    The Influence of Subjects and Environment on Audiovisual Subjective Tests: An International Study

    IEEE Journal of Selected Topics in Signal Processing, vol. 6, no. 6, pp. 640-651

    2012

    DOI: 10.1109/JSTSP.2012.2215306

    Abstract anzeigen

    Traditionally, audio quality and video quality are evaluated separately in subjective tests. Best practices within the quality assessment community were developed before many modern mobile audiovisual devices and services came into use, such as internet video, smart phones, tablets and connected televisions. These devices and services raise unique questions that require jointly evaluating both the audio and the video within a subjective test. However, audiovisual subjective testing is a relatively under-explored field. In this paper, we address the question of determining the most suitable way to conduct audiovisual subjective testing on a wide range of audiovisual quality. Six laboratories from four countries conducted a systematic study of audiovisual subjective testing. The stimuli and scale were held constant across experiments and labs; only the environment of the subjective test was varied. Some subjective tests were conducted in controlled environments and some in public environments (a cafeteria, patio or hallway). The audiovisual stimuli spanned a wide range of quality. Results show that these audiovisual subjective tests were highly repeatable from one laboratory and environment to the next. The number of subjects was the most important factor. Based on this experiment, 24 or more subjects are recommended for Absolute Category Rating (ACR) tests. In public environments, 35 subjects were required to obtain the same Student\textquoterights t-test sensitivity. The second most important variable was individual differences between subjects. Other environmental factors had minimal impact, such as language, country, lighting, background noise, wall color, and monitor calibration. Analyses indicate that Mean Opinion Scores (MOS) are relative rather than absolute. Our analyses show that the results of experiments done in pristine, laboratory environments are highly representative of those devices in actual use, in a typical user environment.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    P. Lebreton, A. Raake, Marcus Barkowsky, P. Le Callet

    Evaluating Depth Perception of 3D Stereoscopic Videos

    IEEE Journal of Selected Topics in Signal Processing, vol. 6, no. 6, pp. 710-720

    2012

    Abstract anzeigen

    3D video quality of experience (QoE) is a multidimensional problem; many factors contribute to the global rating like image quality, depth perception and visual discomfort. Due to this multidimensionality, it is proposed in this paper, that as a complement to assessing the quality degradation due to coding or transmission, the appropriateness of the non-distorted signal should be addressed. One important factor here is the depth information provided by the source sequences. From an application-perspective, the depth-characteristics of source content are of relevance for pre-validating whether the content is suitable for 3D video services. In addition, assessing the interplay between binocular and monocular depth features and depth perception are relevant topics for 3D video perception research. To achieve the evaluation of the suitability of 3D content, this paper describes both a subjective experiment and a new objective indicator to evaluate depth as one of the added values of 3D video.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    M. Urvoy, Marcus Barkowsky, J. Gutiérrez, R. Cousseau, Y. Koudota, V. Ricordel, P. Le Callet, N. García

    NAMA3DS1-COSPAD1: Subjective video quality assessment database on coding conditions introducing freely available high quality 3D stereoscopic sequences

    2012 Fourth International Workshop on Quality of Multimedia Experience

    2012

    Abstract anzeigen

    Research in stereoscopic 3D coding, transmission and subjective assessment methodology depends largely on the availability of source content that can be used in cross-lab evaluations. While several studies have already been presented using proprietary content, comparisons between the studies are difficult since discrepant contents are used. Therefore in this paper, a freely available dataset of high quality Full-HD stereoscopic sequences shot with a semiprofessional 3D camera is introduced in detail. The content was designed to be suited for usage in a wide variety of applications, including high quality studies. A set of depth maps was calculated from the stereoscopic pair. As an application example, a subjective assessment has been performed using coding and spatial degradations. The Absolute Category Rating with Hidden Reference method was used. The observers were instructed to vote on video quality only. Results of this experiment are also freely available and will be presented in this paper as a first step towards objective video quality measurement for 3DTV.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    J. Li, Marcus Barkowsky, P. Le Callet

    Analysis and Improvement of a Paired Comparison Method in the Application of 3DTV Subjective Experiment

    2012 19th IEEE International Conference on Image Processing

    2012

    Abstract anzeigen

    Paired comparison is a frequently used method in psychophysical studies. However, with the increase of the number of the stimuli, the number of comparisons increases exponentially. Square design is one of the balanced sub-set paired comparison methods which could reduce the number of comparisons while producing comparably precise results under some assumptions. However, when there are observation errors from observers' attentiveness, the square design would produce large estimation errors. Thus, an improved square design which is robust to observation errors is proposed. Using a Monte Carlo simulation, the proposed method is evaluated and shows improvement in efficiency. The original design is applied in a visual discomfort subjective test of 3DTV. In addition, both of the two designs are studied by utilizing our previous full comparison data. The test results showed that the proposed improved square design is more robust to observation errors. Another important finding is that the influence of the occurrence of some other stimuli on voting is significant. Whether the proposed method could reduce the prediction errors induced by it is still under study.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    K. Wang, Marcus Barkowsky, K. Brunnström, M. Sjöström, R. Cousseau, P. Le Callet

    Perceived 3D TV Transmission Quality Assessment: Multi-Laboratory Results Using Absolute Category Rating on Quality of Experience Scale

    IEEE Transactions on Broadcasting, vol. 58, no. 4, pp. 544-557

    2012

    Abstract anzeigen

    Inspired by the rapidly increasing popularity of 3D movies, there is an industrial push for 3DTV services to the home. One important factor for the success and acceptance by the viewers is a positive quality of experience (QoE) of the new service when delivered. The questions of how to efficiently deliver 3DTV service to the home, and how to evaluate the visual quality perceived by end users are a recent research focus. We have investigated users\textquoteright experience of stereoscopic 3D video quality by preparing two subjective assessment datasets. The first dataset aimed at the evaluation of efficient transmission in the transmission error free case, while the second focused on error concealment. A total of three subjective assessments, two for first dataset and one for the second, were performed using the Absolute Category Rating with Hidden unimpaired Reference video (ACR-HR) method. The experimental setup allows to show that the ACR-HR subjective method provides repeatable results across labs and across conditions for video quality. It was also verified that MVC is more efficient than H.264 simulcast coding. Furthermore it was discovered that based on the same level of quality of experience spatial down-sampling may lead to better bitrate efficiency while temporal down-sampling is not acceptable. When network impairments occur, traditional error 2D concealment methods need to be reinvestigated as they were outperformed by displaying the same view for both eyes (switching to 2D presentation).

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    S. Tourancheau, K. Wang, J. Bulat, R. Cousseau, L. Janowski, K. Brunnström, Marcus Barkowsky

    Reproducibility of crosstalk measurements on active glasses 3D LCD displays based on temporal characterization

    Proceedings of SPIE Vol. 8288: Stereoscopic Displays and Applications XXIII

    2012

    ISBN: 9780819489357

    Abstract anzeigen

    Crosstalk is one of the main display-related perceptual factors degrading image quality and causing visual dis-comfort on 3D-displays. It causes visual artifacts such as ghosting eects, blurring, and lack of color delitywhich are considerably annoying and can lead to diculties to fuse stereoscopic images. On stereoscopic LCDwith shutter-glasses, crosstalk is mainly due to dynamic temporal aspects: imprecise target luminance (highlydependent on the combination of left-view and right-view pixel color values in disparity regions) and synchro-nization issues between shutter-glasses and LCD. These dierent factors inuence largely the reproducibilityof crosstalk measurements across laboratories and need to be evaluated in several dierent locations involvingsimilar and diering conditions. In this paper we propose a fast and reproducible measurement procedure forcrosstalk based on high-frequency temporal measurements of both display and shutter responses. It permitsto fully characterize crosstalk for any right/left color combination and at any spatial position on the screen.Such a reliable objective crosstalk measurement method at several spatial positions is considered a mandatoryprerequisite for evaluating the perceptual inuence of crosstalk in further subjective studies.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    K. Brunnström, I. Sedano, K. Wang, Marcus Barkowsky, M. Kihl, P. Le Callet, Patrick, M. Sjöström, A. Aurelius

    2D No-Reference Video Quality Model Development and 3D Video Transmission Quality

    Sixth International Workshop on Video Processing and Quality Metrics for Consumer Electronics - VPQM 2012 (Jan 2012; Scottsdale, AZ, USA)

    2012

    Abstract anzeigen

    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.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    W. Chen, J. Fournier, Marcus Barkowsky, P. Le Callet

    Exploration of Quality of Experience of Stereoscopic Images: Binocular Depth

    Sixth International Workshop on Video Processing and Quality Metrics for Consumer Electronics - VPQM 2012 (Jan 2012; Scottsdale, AZ, USA)

    2012

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Y. Pitrey, P. Hummelbrunner, B. Kitzinger, S. Buchinger, Marcus Barkowsky, P. Le Callet, R. Pepion

    Influence of Shooting Conditions, Re-Encoding and Viewing Conditions on the Perceived Quality of User-Generated Videos

    Sixth International Workshop on Video Processing and Quality Metrics for Consumer Electronics - VPQM 2012 (Jan 2012; Scottsdale, AZ, USA)

    2012

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    J. Li, Marcus Barkowsky, P. Le Callet

    Visual Discomfort Induced by Relative Disparity and Planar Motion of Stereoscopic Images

    first Sino French Workshop on Information and Communication Technologies, Nantes, France

    2011

    Abstract anzeigen

    Viewers often complain of visual discomfort or visual fatigue after viewing the stereoscopic images. In this paper, we investigated the effects of planar motion at different depth levels on visual discomfort. In the subjective experiments, the Paired Comparison method was used to allow for a precise measurement. The Bradley-Terry model was used to analyze the subjective experimental data. The experimental results indicated that the relative angular disparity between foreground object and background played a more important role in determining the visual discomfort than the vergence-accommodation conflict. Furthermore, viewers might experience more visual discomfort with the increase of planar motion velocity. In a practical application of our study, it may be concluded that for stereoscopic motion images, the depth range for fast motion sequences should be significantly reduced and for slow motion sequences, the depth range may be increased.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Wang, J., Marcus Barkowsky, V. Ricordel, P. Le Callet

    Clarifying how defocus blur and disparity affect the perceived depth

    Proceedings of the First Sino-French Workshop on Education and Research collaborations in Information and Communication Technologies (SIFWICT) 2011, Nantes, France

    2011

    Abstract anzeigen

    Human visual system takes advantage of different cues simultaneously to provide us the perception of depth. When 3D images are shown on a planar stereoscopic display, binocular disparity becomes a pre-eminent depth cue. But it induces simultaneously the conflict between accommodation and vergence, which is often considered as a main reason for visual discomfort. If we limit this visual discomfort by decreasing the disparity, the apparent depth also decreases. We propose to decrease the (binocular) disparity of 3D presentations, and to reinforce (monocular) cues to compensate the loss of perceived depth and keep an unaltered apparent depth. The influence of a monocular depth cue, blur, on the apparent depth of stereoscopic scenes was studied in our recent work. We conducted a subjective experiment using a two-alternative forced choice task. Observers were required to identify the larger perceived depth in a pair of 3D images with/without blur. By fitting the result to a psychometric function, we obtained points of subjective equality in terms of disparity. We found that when blur is added to the background of the image, the viewer can perceive larger depth comparing to the images without any blur in the background. The increase of perceived depth can be considered as a function of the relative distance between the foreground and background, while it is insensitive to the distance between the viewer and the depth plane at which the blur is added.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    N. Staelens, I. Sedano, Marcus Barkowsky, L. Janowski, K. Brunnström, P. Le Callet

    Standardized Toolchain And Model Development For Video Quality Assessment ‐ The Mission Of The Joint Effort Group In Vqeg

    Proceedings of 2011 Third International Workshop on Quality of Multimedia Experience (QoMEX), Mechelen, Belgique

    2011

    Abstract anzeigen

    Since 1997, the Video Quality Experts Group (VQEG) has been active in the field of subjective and objective video quality assessment. The group has validated competitive quality metrics throughout several projects. Each of these projects requires mandatory actions such as creating a testplan and obtaining databases consisting of degraded video sequences with corresponding subjective quality ratings. Recently, VQEG started a new open initiative, the Joint Effort Group (JEG), for encouraging joint collaboration on all mandatory actions needed to validate video quality metrics. Within the JEG, effort is made to advance the field of both subjective and objective video quality measurement by providing proper software tools and subjective databases to the community. One of the subprojects of the JEG is the joint development of a hybrid H.264/AVC objective quality metric. In this paper, we introduce the JEG and provide an overview of the different ongoing activities within this newly started group.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    P. Lebreton, A. Raake, Marcus Barkowsky, P. Le Callet

    A Subjective Evaluation of 3D IPTV Broadcasting Implementations Considering Coding and Transmission Degradation

    IEEE International Symposium on Multimedia (ISM)

    2011

    Abstract anzeigen

    This paper describes the results of a subjective test to assess current technology used for 3DTV broadcasting. As a first aspect, the performance of the currently deployed coding schemes was compared to state of the art algorithms. Our results show that down sampling and packing 3D stereoscopic videos according to the so called Side-By-Side format gives the highest perceived quality for a given bit rate. The second aspect of the study was to investigate how common 2D error concealment algorithms perform in case of 3D, and how their 3D-related performance compares with the 2D case. The results provide information on whether binocular suppression or binocular rivalries play the most important role for 3D video quality under transmission error. The results indicate that binocular rivalries and related visual discomfort are the dominant factors. Another aspect of the paper is a comparison of the test results with results from different labs to evaluate the repeatability of a subjective experiment in the 3D case, and to compare the employed test methodologies. Here, the study shows the variation between observers when they are rating visual discomfort and illustrates the difficulty to evaluate this new dimension.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Wang, J., Marcus Barkowsky, V. Ricordel, P. Le Callet

    Quantifying how the Combination of Blur and Disparity affects the Perceived Depth

    Proceedings of SPIE Vol. 7865: Human Vision and Electronic Imaging XVI

    2011

    Abstract anzeigen

    The influence of a monocular depth cue, blur, on the apparent depth of stereoscopic scenes will be studied in this paper. When 3D images are shown on a planar stereoscopic display, binocular disparity becomes a pre-eminent depth cue. But it induces simultaneously the conflict between accommodation and vergence, which is often considered as a main reason for visual discomfort. If we limit this visual discomfort by decreasing the disparity, the apparent depth also decreases. We propose to decrease the (binocular) disparity of 3D presentations, and to reinforce (monocular) cues to compensate the loss of perceived depth and keep an unaltered apparent depth. We conducted a subjective experiment using a two- alternative forced choice task. Observers were required to identify the larger perceived depth in a pair of 3D images with/without blur. By fitting the result to a psychometric function, we obtained points of subjective equality in terms of disparity. We found that when blur is added to the background of the image, the viewer can perceive larger depth comparing to the images without any blur in the background. The increase of perceived depth can be considered as a function of the relative distance between the foreground and background, while it is insensitive to the distance between the viewer and the depth plane at which the blur is added.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Y. Pitrey, U. Engelke, Marcus Barkowsky, R. Pépion, P. Le Callet

    Aligning Subjective Tests using a Low Cost Common Set

    QoE for Multimedia Content Sharing, Lisbon, Portugal

    2011

    Abstract anzeigen

    In this paper we use a common set between three subjective tests to build a linear mapping of the results of two tests onto the scale of one test identi ed as the reference test. We present our low-cost approach for the design of the common set and discuss the choice of the reference test. The mapping is then used to merge the outcomes of the three tests and provide an interesting comparison of the impact of coding artifacts, transmission errors and error-concealment in the context of Scalable Video Coding.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Y. Pitrey, U. Engelke, P. Le Callet, Marcus Barkowsky, R. Pépion

    Subjective Quality of SVC-coded Videos with different Error-Patterns concealed using Spatial Scalability

    Proceedings of the 3rd European Workshop on Visual Information Processing (EUVIP) 2011, Paris, France

    2011

    Abstract anzeigen

    Degradation of network performance during video transmission may lead to disturbing visual artifacts. Some packets might be lost, corrupted or delayed, making it impossible to properly decode the video data on time at the receiver. The quality of the error-concealment technique, as well as the spatial and temporal position of the artifacts have a large impact on the perceived quality after decoding. In this paper, we use the spatial scalability feature of Scalable Video Coding (SVC) for error-concealment. This enables the transmission of a lower resolution video with a higher robustness, for example using unequal error protection. Under the assumption that only the higher resolution video would be affected, we evaluated the visual impact of packet losses in a large scale subjective video quality experiment using the Absolute Category Rating method. The number of impairments, the duration, and the interval between impairments as well the quality of the encoded lower resolution video are varied in a systematic evaluation. This allows for analyzing the influence of each factor both independently and jointly.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    J. Li, Marcus Barkowsky, P. Le Callet

    The Influence of Relative Disparity and Planar Motion Velocity on Visual Discomfort of Stereoscopic Videos

    Proceedings of 2011 Third International Workshop on Quality of Multimedia Experience (QoMEX), Mechelen, Belgique

    2011

    Abstract anzeigen

    The vergence-accommodation conflict, excessive screen disparity,binocular distortions and the motion component in stereoscopicvideos are considered as main factors that may induce visualdiscomfort. In our previous study which was based on theexperts-only experiment, we also found that the large relativedisparity between the foreground and background and the fast planarmotion were more likely to induce visual discomfort. In this study,we conducted the same subjective experiment but on non-expertobservers. The subjective experiment results coincided with ourprevious findings. The two objective visual discomfort modelsdeveloped in our previous study have been evaluated and showedhigh correlation with subjective data. Finally, we found that theobservers could be classified into different clusters according to theirvisual discomfort sensitivity to the velocity or the relative disparity.For some observers, the velocity is the predominant factor that mayinduce visual discomfort; some consider that the relative disparity isthe key factor, and some are sensitive to both the velocity and relativedisparity.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    Q. Huynh-Thu, Marcus Barkowsky, P. Le Callet

    The Importance of Visual Attention in Improving the 3D-TV Viewing Experience: Overview and New Perspectives

    IEEE Transactions on Broadcasting, vol. 57, no. 2, pp. 421-431

    2011

    Abstract anzeigen

    Three-dimensional video content has attracted much attention in both the cinema and television industries, because 3D is considered to be the next key feature that can significantly enhance the visual experience of viewers. However, one of the major challenges is the difficulty in providing high quality images that are comfortable to view and that also meet signal transmission requirements over a limited bandwidth for display on television screens. The different processing steps that are necessary in a 3D-TV delivery chain can all introduce artifacts that may create problems in terms of human visual perception. In this paper, we highlight the importance of considering 3D visual attention when addressing 3D human factors issues. We provide a review of the field of 3D visual attention, discuss the challenges in both the understanding and modeling of 3D visual attention, and provide guidance to researchers in this field. Finally, we identify perceptual issues generated during the various steps in a typical 3D-TV broadcasting delivery chain, review them and explain how consideration of 3D visual attention modeling can help improve the overall 3D viewing experience.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    Marcus Barkowsky, S. Tourancheau, K. Brunnström, K. Wang, B. Andrén

    55.3: Crosstalk Measurements of Shutter Glasses 3D Displays

    SID Symposium Digest of Technical Papers, vol. 42, no. 1, pp. 812-815

    2011

    Abstract anzeigen

    Crosstalk is probably one of the main perceptual factors contributing to perceived image quality and visual comfort. The Video Quality Experts Group (VQEG) within their 3D video quality project is specifying a practical measurement procedure that will produce consistent results across laboratories. This paper is part of that effort. Two different method of measuring cross talk on shutter glasses stereo displays have been studied. One is based on time average luminance measurements and the other on temporal measurements. The results show that crosstalk is roughly 0.5% but that there are differences in the crosstalk between the two eyes in the shutter glasses.