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

    Beitrag (Sammelband oder Tagungsband)

    J. Li, Marcus Barkowsky, Wang, J., P. Le Callet

    Study on Visual Discomfort Induced by Stimulus Movement at Fixed Depth on Stereoscopic Displays using Shutter Glasses

    2011 17th International Conference on Digital Signal Processing (DSP)

    2011

    Abstract anzeigen

    Stereoscopic motion images are able to provide observers with realistic and immersive viewing experience. However, observers often experience visual discomfort during the viewing process. In this paper, we investigated the relationship between visual discomfort and the planar motion at different depth levels. The Paired Comparison method was used in the subjective experiments to allow for a precise measurement. 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, the results showed that with the increase of planar motion velocity, viewers might experience more visual discomfort. To quantify the effects of relative angular disparity and velocity on visual discomfort, two visual discomfort models were constructed. The preferred model was chosen based on the performance as well as the algorithmic complexity. This model can be used as an index for other related researches.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    New stereoscopic video shooting rule based on stereoscopic distortion parameters and comfortable viewing zone

    Proceedings of SPIE Vol. 7863: Stereoscopic Displays and Applications XXII;

    2011

    Abstract anzeigen

    Human binocular depth perception, the most important element brought by 3DTV, is proved to be closely connected to not only the content acquisition (camera focal length, camera baseline and etc.) but also the viewing environment (viewing distance, screen size and etc.). Conventional 3D stereography rule in the literature usually consider the general viewing condition and basic human factors to guide the content acquisition, such as assuming human inter-pupil baseline as the maximum disparity. A lot of new elements or problems of stereoscopic viewing was not considered or precisely defined so that advanced shooting rule is needed to guarantee the overall quality of stereoscopic video. In this paper, we proposed a new stereoscopic video shooting rule considering two most important issues in 3DTV: stereoscopic distortion and comfortable viewing zone. Firstly, a mathematic model mapping the camera space to visualization space is established in order to geometrically estimate the stereoscopic depth distortion. Depth and shape distortion factors are defined and used to describe the stereoscopic distortion. Secondly, comfortable viewing zone (or Depth of focus) is considered to reduce the problem of visual discomfort and visual fatigue. The new shooting rule is to optimize the camera parameters (focal length, camera baseline and etc.) in order to control depth and shape distortion and also guarantee that the perceived scene is located in comfortable viewing zone as possible. However, in some scenarios, the above two conditions cannot be fulfill simultaneously, even sometimes contradict with each other so that priority should be decided. In this paper, experimental stereoscopic synthetic content generation with various sets of camera parameters and various sets of scenes representing different depth range are presented. Justification of the proposed new shooting rule is based on 3D concepts (depth rendering, visual comfort and visual experience) subjective video assessment. The results of this study will provide a new method to propose camera parameters based on management of new criteria (shape distortion and depth of focus) in order to produce optimized stereoscopic images and videos.

    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

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Marcus Barkowsky, R. Cousseau, P. Le Callet

    Is visual fatigue changing the perceived depth accuracy on an autostereoscopic display?

    Proceedings of SPIE Vol. 7863: Stereoscopic Displays and Applications XXII

    2011

    Abstract anzeigen

    In this paper, a subjective study is presented which aims to measure the minimum perceivable depth difference on an autostereoscopic display in order to provide an indication for visual fatigue. The developed experimental setup was used to compare the subject's performance before and after 3D excitation on an autostereoscopic display. By comparing the results to a verification session with 2D excitation, the effect of 3D visual fatigue can be isolated. It was seen that it is possible to reach the threshold of acuity for stereo disparity on that autostereoscopic display. It was also found that the measured depth acuity is slightly higher after 3D viewing than after 2D viewing.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    Subjective evaluation of HDTV stereoscopic videos in IPTV scenarios using absolute category rating

    Proceedings of SPIE Vol. 7863: Stereoscopic Displays and Applications XXII

    2011

    Abstract anzeigen

    Broadcasting of high definition (HD) stereobased 3D (S3D) TV are planned, or has already begun, in Europe, the US, and Japan. Specific data processing operations such as compression and temporal and spatial resampling are commonly used tools for saving network bandwidth when IPTV is the distribution form, as this results in more efficient recording and transmission of 3DTV signals, however at the same time it inevitably brings quality degradations to the processed video. This paper investigated observers quality judgments of state of the art video coding schemes (simulcast H.264/AVC or H.264/MVC), with or without added temporal and spatial resolution reduction of S3D videos, by subjective experiments using the Absolute Category Rating method (ACR) method. The results showed that a certain spatial resolution reduction working together with high quality video compressing was the most bandwidth efficient way of processing video data when the required video quality is to be judged as "good" quality. As the subjective experiment was performed in two different laboratories in two different countries in parallel, a detailed analysis of the interlab differences was performed.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    U. Engelke, Marcus Barkowsky, P. Le Callet, H.-J. Zepernick

    Modelling Saliency Awareness for Objective Video Quality Assessment

    IEEE International Workshop on Quality of Multimedia Experience (QoMEX) 2010, Trondheim, Norway

    2010

    Abstract anzeigen

    Existing video quality metrics do usually not take into consideration that spatial regions in video frames are of varying saliency and thus, differently attract the viewer\textquoterights attention. This paper proposes a model of saliency awareness to complement existing video quality metrics, with the aim to improve the agreement of objectively predicted quality with subjectively rated quality. For this purpose, we conducted a subjective experiment in which human observers rated the annoyance of videos with transmission distortions appearing either in a salient region or in a non-salient region. The mean opinion scores confirm that distortions in salient regions are perceived much more annoying. It is shown that application of the saliency awareness model to two video quality metrics considerably improves their quality prediction performance.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    Subjective Quality Evaluation of H.264 High-Definition Video Coding versus Spatial Up-Scaling and Interlacing

    QoE for Multimedia Content Sharing, Tampere, Finlande

    2010

    Abstract anzeigen

    The upcoming High-De nition format for video display provides high-quality content, especially when displayed on adapted devices. When combined with video coding techniques such as MPEG-4 AVC/H.264, the transmission of High-De nition video content on broadcast networks becomes possible. Nonetheless, transmitting and decoding such video content is a real challenge. Therefore, intermediate formats based on lower frame resolutions or interlaced coding are still provided to address targets with limited resources. Using these formats, the nal video quality depends on the postprocessing tools employed at the receiver to upsample and de-interlace these streams. In this paper, we compare the full-HD format to three possible scenarios to generate a full-HD stream from intermediate formats. We present the results of subjective tests that compare the visual quality of each scenario when using the same bitrate. The results show that using the same bitrate, the videos generated from lower-resolution formats reach similar quality compared to the full-HD videos.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    Subjective Quality Assessment Of MPEG-4 Scalable Video Coding In a Mobile Scenario

    European Workshop on Visual Information Processing (EUVIP) 2010, Paris, France

    2010

    Abstract anzeigen

    Scalable Video Coding provides several levels of video encapsulated in a single video stream. In a transmission scenario such as broadcasting, this structure is quite advantageous as it can be used to address heterogeneous decoding targets with variable needs and requirements. However, this adaptability comes at a slight cost in coding efficiency when compared to single-layer coding. Based on subjective experiments, this cost is evaluated in this paper by comparing the new MPEG-4 Scalable Video Coding (SVC) standard with the now-established MPEG-4 AVC standard. Two scenarios are analyzed in the context of mobile transmission applications. The first scenario uses the same bitrate for SVC and AVC, leading to a slightly lower PSNR for SVC. The second scenario uses the same PSNR for SVC and AVC, leading to a slightly lower bitrate for AVC. The results of the subjective tests illustrate several interesting aspects of the relation between the performance of the two standards. First, we observe that the offset between AVC and SVC is not severe, though statistically significant in terms of user Mean Opinion Score (MOS) in such a context. Second, while adding another layer to SVC always leads to a performance loss, the impact of this loss decreases when the number of layers increases.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    Evaluation of MPEG4-SVC for QoE Protection in the Context of Transmission Errors

    Proceedings of SPIE Vol. 7798: Applications of Digital Image Processing XXXIII, San Diego, CA, USA

    2010

    Abstract anzeigen

    Scalable Video Coding (SVC) provides a way to encapsulate several video layers with increasing quality and resolution in a single bitstream. Thus it is particularly adapted to address heterogeneous networks and a wide variety of decoding devices. In this paper, we evaluate the interest of SVC in a different context, which is error concealment after transmission on networks subject to packet loss. The encoded scalable video streams contain two layers with different spatial and temporal resolutions designed for mobile video communications with medium size and average to low bitrates. The main idea is to use the base layer to conceal errors in the higher layers if they are corrupted or lost. The base layer is first upscaled either spatially or temporally to reach the same resolution as the layer to conceal. Two error-concealment techniques using the base layer are then proposed for the MPEG-4 SVC standard, involving frame-level concealment and pixel-level concealment. These techniques are compared to the upscaled base layer as well as to a classical single-layer MPEG- 4 AVC/H.264 error-concealment technique. The comparison is carried out through a subjective experiment, in order to evaluate the Quality-of-Experience of the proposed techniques. We study several scenarios involving various bitrates and resolutions for the base layer of the SVC streams. The results show that SVC-based error concealment can provide significantly higher visual quality than single-layer-based techniques. Moreover, we demonstrate that the resolution and bitrate of the base layer have a strong impact on the perceived quality of the concealment.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    Subjective Quality Assessment of Error Concealment Strategies for 3DTV in the presence of asymmetric Transmission Errors

    2010 18th International Packet Video Workshop

    2010

    Abstract anzeigen

    The transmission of 3DTV sequences over packet based networks may result in degradations of the video quality due to packet loss. In the conventional 2D case, several different strategies are known for extrapolating the missing information and thus concealing the error. In 3D however, the residual error after concealment of one view might leads to binocular rivalry with the correctly received second view. In this paper, three simple alternatives are presented: frame freezing, a reduced playback speed, and displaying only a single view for both eyes, thus effectively switching to 2D presentation. In a subjective experiment the performance in terms of quality of experience of the three methods is evaluated for different packet loss scenarios. Error-free encoded videos at different bit rates have been included as anchor conditions. The subjective experiment method contains special precautions for measuring the Quality of Experience (QoE) for 3D content and also contains an indicator for visual discomfort. The results indicate that switching to 2D is currently the best choice but difficulties with visual discomfort should be expected even for this method.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    Video Quality Assessment: From 2D to 3D ‐ Challenges and Future Trends

    2010 IEEE International Conference on Image Processing

    2010

    Abstract anzeigen

    Three-dimensional (3D) video is gaining a strong momentum both in the cinema and broadcasting industries as it is seen as a technology that will extensively enhance the user's visual experience. One of the major concerns for the wide adoption of such technology is the ability to provide sufficient visual quality, especially if 3D video is to be transmitted over a limited bandwidth for home viewing (i.e. 3DTV). Means to measure perceptual video quality in an accurate and practical way is therefore of highest importance for content providers, service providers, and display manufacturers. This paper discusses recent advances in video quality assessment and the challenges foreseen for 3D video. Both subjective and objective aspects are examined. An outline of ongoing efforts in standards-related bodies is also provided.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Marcus Barkowsky, P. Le Callet

    On the Perceptual Similarity of Realistic Looking Tone Mapped High Dynamic Range Images

    2010 IEEE International Conference on Image Processing

    2010

    Abstract anzeigen

    High Dynamic Range (HDR) images are usually displayed on conventional Low Dynamic Range (LDR) displays because of the limited availability of HDR displays. For the conversion of the large dynamic luminance range into the eight bit quantized values, parameterized Tone Mapping Operators (TMO) are applied. Human observers are able to optimize the parameters in order to get the highest Quality of Experience by judging the displayed LDR images on a realism scale. In the study presented in this paper, two TMOs with three parameters each were evaluated by observers in a subjective experiment. Although the chosen parameter settings vary largely, the chosen images appear to have the same QoE for the observers. In order to assess this similarity objectively, three commonly used image quality measurement algorithms were applied. Their agreement with the preference of the observers was analyzed and it was found that the Visual Difference Predictor (VDP) outperforms the Structural Similarity Index and the Root Mean Square Error. A threshold value for VDP is derived that indicates when two LDR images appear to have the same Quality of Experience.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    U. Engelke, Marcus Barkowsky, P. Le Callet, H.-J. Zepernick

    Modelling Saliency Awareness for Objective Video Quality Assessment

    International Workshop on Quality of Multimedia Experience (QoMEX) [June 2010; Trondheim, Norway]

    2010

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    New Requirements of Subjective Video Quality Assessment Methodologies for 3DTV

    Fifth International Workshop on Video Processing and Quality Metrics (VPQM) [Scottsdale, AZ, USA]

    2010

    Abstract anzeigen

    In this paper, the new challenges of 3DTV for subjective assessment are discussed. Conventional 2D methods have severe limitations which will be revealed. Based on the understanding of the new characteristics brought by 3DTV, changes and additions in the requirements for subjective assessment are proposed in order to develop a novel subjective video quality assessment methodology for 3DTV. In particular, depth rendering for 3D display is selected to give a further discussion. The depth rendering abilities are defined as a combination of the physical parameters and the perceptual constrains. We analyze different types of stereoscopic and multiview displays. Several problems regarding depth rendering are discussed in order to highlight the diversity and complexity of assessing 3DTV.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Marcus Barkowsky, P. Campisi, P. Le Callet, V. Rizzo

    Crosstalk measurement and mitigation for autostereoscopic displays

    Proceedings of SPIE Vol. 7526: Three-Dimensional Image Processing (3DIP) and Applications

    2010

    Abstract anzeigen

    In this paper we address the problem of crosstalk reduction for autostereoscopic displays. Crosstalk refers to the perception of one or more unwanted views in addition to the desired one. Specifically, the proposed approach consists of three different stages: a crosstalk measurement stage, where the crosstalk is modeled, a filter design stage, based on the results obtained out of the measurements, to mitigate the crosstalk effect, and a validation test carried out by means of subjective measurements performed in a controlled environment as recommended in ITU BT 500-11. Our analysis, synthesis, and subjective experiments are performed on the Alioscopy® display, which is a lenticular multiview display.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Marcus Barkowsky, P. Le Callet

    The influence of autostereoscopic 3D displays on subsequent task performance

    Proceedings of SPIE Vol. 7524: Stereoscopic Displays and Applications XXI

    2010

    Abstract anzeigen

    Viewing 3D content on an autostereoscopic is an exciting experience. This is partly due to the fact that the 3D effect is seen without glasses. Nevertheless, it is an unnatural condition for the eyes as the depth effect is created by the disparity of the left and the right view on a flat screen instead of having a real object at the corresponding location. Thus, it may be more tiring to watch 3D than 2D. This question is investigated in this contribution by a subjective experiment. A search task experiment is conducted and the behavior of the participants is recorded with an eyetracker. Several indicators both for low level perception as well as for the task performance itself are evaluated. In addition two optometric tests are performed. A verification session with conventional 2D viewing is included. The results are discussed in detail and it can be concluded that the 3D viewing does not have a negative impact on the task performance used in the experiment.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Marcus Barkowsky, M. Pinson, R. Pépion, P. Le Callet

    Analysis of Freely Available Dataset for HDTV including Coding and Transmission Distortions

    Fifth International Workshop on Video Processing and Quality Metrics (VPQM) [Scottsdale, AZ, USA]

    2010

    Abstract anzeigen

    We present the design, preparation, and analysis of a subjective experiment on typical HDTV sequences and scenarios. This experiment follows the guidelines of ITU and VQEG in order to obtain reproducible results. The careful selection of content and distortions extend over a wide and realistic range of typical transmission scenarios. Detailed statistical analysis provides important insight into the relationship between technical parameters of encoding, transmission and decoding and subjectively perceived video quality.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Marcus Barkowsky, R. Cousseau, P. Le Callet

    Influence of Depth Rendering on the Quality of Experience for an Autostereoscopic Display

    International Workshop on Quality of Multimedia Experience (QoMEx)

    2009

    Abstract anzeigen

    Autostereoscopic displays simplify the presentation of 3D content because they do not require any glasses and they allow the perception of motion parallax. While the perception of depth is certainly an added value, the technical rendering process of the current display technology also introduces artifacts. For the viewer, the tradeoff may be expressed in terms of quality of experience. However, quality of experience assessment related to 3D is still an open issue. Towards this goal, several original subjective test methods are proposed and compared that are meant for assessing the quality of experience. A split-screen setup simultaneously displays a 2D and a 3D presentation. The observers vote according to their preference in terms of quality of experience. In four experiments, the influence of the depth rendering process is evaluated. The results indicate that the degradation by the depth rendering process may easily dominate the added value of depth in a content specific manner.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    Marcus Barkowsky, J. Bialkowski, B. Eskofier, R. Bitto, A. Kaup

    Temporal Trajectory Aware Video Quality Measure

    IEEE Journal of Selected Topics in Signal Processing, vol. 3, no. 2, pp. 266-279

    2009

    Abstract anzeigen

    The measurement of video quality for lossy and low-bitrate network transmissions is a challenging topic. Especially, the temporal artifacts which are introduced by video transmission systems and their effects on the viewer's satisfaction have to be addressed. This paper focuses on a framework that adds a temporal distortion awareness to typical video quality measurement algorithms. A motion estimation is used to track image areas over time. Based on the motion vectors and the motion prediction error, the appearance of new image areas and the display time of objects is evaluated. Additionally, degradations which stick to moving objects can be judged more exactly. An implementation of this framework for multimedia sequences, e.g., QCIF, CIF, or VGA resolution, is presented in detail. It shows that the processing steps and the signal representations that are generated by the algorithm follow the reasoning of a human observer in a subjective experiment. The improvements that can be achieved with the newly proposed algorithm are demonstrated using the results of the Multimedia Phase I database of the Video Quality Experts Group.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    U. Fecker, Marcus Barkowsky, A. Kaup

    Histogram-Based Prefiltering for Luminance and Chrominance Compensation of Multiview Video

    IEEE Transactions on Circuits and Systems for Video Technology, vol. 18, no. 9, pp. 1258-1267

    2008

    Abstract anzeigen

    Significant advances have recently been made in the coding of video data recorded with multiple cameras. However, luminance and chrominance variations between the camera views may deteriorate the performance of multiview codecs and image-based rendering algorithms. A histogram matching algorithm can be applied to efficiently compensate for these differences in a prefiltering step. A mapping function is derived which adapts the cumulative histogram of a distorted sequence to the cumulative histogram of a reference sequence. If all camera views of a multiview sequence are adapted to a common reference using histogram matching, the spatial prediction across camera views is improved. The basic algorithm is extended in three ways: a time-constant calculation of the mapping function, RGB color conversion, and the use of global disparity compensation. The best coding results are achieved when time-constant histogram calculation and RGB color conversion are combined. In this case, the usage of histogram matching prior to multiview encoding leads to substantial gains in the coding efficiency of up to 0.7 dB for the luminance component and up to 1.9 dB for the chrominance components. This prefiltering step can be combined with block-based illumination compensation techniques that modify the coder and decoder themselves, especially with the approach implemented in the multiview reference software of the joint video team (JVT). Additional coding gains up to 0.4 dB can be observed when both methods are combined.