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

    Beitrag (Sammelband oder Tagungsband)

    A. Aldahdooh, Marcus Barkowsky, P. Le Callet

    The impact of complexity in the rate-distortion optimization: A visualization tool

    2015 International Conference on Systems, Signals and Image Processing (IWSSIP)

    2015

    Abstract anzeigen

    Recently, the new video coding standard, High Efficiency Video Coding (HEVC), was released. A 50% bitrate reduction at the same visual quality relative to the previous standard was achieved. These gains are partly related to tools that increase complexity such as coding decisions taken on smaller image areas or further improvements in motion compensated coding. This paper addresses the complexity issue, i.e. the execution time, and its impact when it is combined with the bitrate and distortion optimization of the video coding. Given a set of encoder configurations that restrict the encoding such that the complexity varies, an analysis including a visualization tool is proposed to help the user to select the best configuration for a specific amount of rate, distortion and complexity. A possible targeted applications are also introduced.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    Open perceptual binocular and monocular descriptors for stereoscopic 3D images and video characterization

    2015 Seventh International Workshop on Quality of Multimedia Experience (QoMEX)

    2015

    Abstract anzeigen

    This paper presents a toolbox for monocular and binocular depth estimation and an analysis of performance for some of these. At first, the definition of an appropriate depth indicator (DI) metric for 3D contents is discussed. To this aim, different algorithms from the literature for the characterization of 3D videos are compared. Results show that the simple 7.5 percentile of the disparity map values can already be an indicator, even though it may fail to address several perceptual aspects. In the latter cases, more advanced algorithms presented in this paper may be a better approach. In a second step, monocular depth indicators are described and analyzed in this paper. All code and tools enabling binocular and monocular depth estimation such as depth-map estimation, depth map characterization and monocular depth cue indicator computation is provided open-source. This will enable researchers to further characterize their 3D and 2D contents, for example before running a subjective experiment, or to automatically pre-screen 3D content that is to be presented to a larger number of viewers.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

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

    Visual Discomfort Induced by Three-Dimensional Display Technology (in Chinese)

    Laser and Optoelectronics Progress, vol. 52, no. 3

    2015

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    K. Berger, Y. Koudota, Marcus Barkowsky, P. Le Callet

    Subjective Quality Assessment Comparing UHD and HD Resolution in HEVC Transmission Chain

    2015 Seventh International Workshop on Quality of Multimedia Experience (QoMEX)

    2015

    Abstract anzeigen

    Ultra High Definition Television (UHDTV) is an emerging broadcasting system, aiming to replace the current High Definition Television (HDTV) in the near future. One aspect of UHDTV is to allow for higher resolutions, notably UHD1, which requires a four times increased datarate for uncompressed transmission compared to Full-HD resolution. As bandwidth for transmission channels in television broadcast is often a fixed value, this study provides information about the perceived quality for transmitting UHD1 content compared to Full-HD content at the same bitrate encoded with HEVC. Content influence is tested with 15 video contents and 4 bitrates are individually chosen per content to span the range of the perceptual scale. The methodology of Absolute Category Rating with Hidden Reference (ACR-HR) is used to collect votes from 24 viewers. The statistical analysis of the collected data shows that, in most cases, there is no significant quality difference between videos transmitted in Full-HD and UHD1 resolution but that the results strongly depend on the content type and on the capture quality. It is also shown that the required bitrate for achieving a chosen broadcast quality level varies with content by a factor of about 14 in HEVC coding.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    G. van Wallendael, N. Staelens, E. Masala, Marcus Barkowsky

    Full-HD HEVC-Encoded Video Quality Assessment Database

    Ninth International Workshop on Video Processing and Quality Metrics (VPQM) [Feb 2015; Chandler, AZ, USA]

    2015

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    Marcus Barkowsky, E. Masala, G. van Wallendael, K. Brunnström, N. Staelens, P. Le Callet

    Objective Video Quality Assessment ‐- Towards Large Scale Video Database Enhanced Model Development

    IEICE Transactions on Communications, vol. E-98b, no. 1, pp. 2-11

    2015

    Abstract anzeigen

    The current development of video quality assessment algorithms suffers from the lack of available video sequences for training, verification and validation to determine and enhance the algorithm's application scope. The Joint Effort Group of the Video Quality Experts Group (VQEG-JEG) is currently driving efforts towards the creation of large scale, reproducible, and easy to use databases. These databases will contain bitstreams of recent video encoders (H.264, H.265), packet loss impairment patterns and impaired bitstreams, pre-parsed bitstream information into files in XML syntax, and well-known objective video quality measurement outputs. The database is continuously updated and enlarged using reproducible processing chains. Currently, more than 70,000 sequences are available for statistical analysis of video quality measurement algorithms. New research questions are posed as the database is designed to verify and validate models on a very large scale, testing and validating various scopes of applications, while subjective assessment has to be limited to a comparably small subset of the database. Special focus is given on the principles guiding the database development, and some results are given to illustrate the practical usefulness of such a database with respect to the detailed new research questions.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    K. Zhu, Marcus Barkowsky, M. Shen, P. Callet, D. Saupe

    Optimizing feature pooling and prediction models of VQA algorithms

    2014 IEEE International Conference on Image Processing (ICIP)

    2014

    Abstract anzeigen

    In this paper, we propose a strategy to optimize feature pooling and prediction models of video quality assessment (VQA) algorithms with a much smaller number of parameters than methods based on machine learning, such as neural networks. Based on optimization, the proposed mapping strategy is composed of a global linear model for pooling extracted features, a simple linear model for local alignment in which local factors depend on source videos, and a non-linear model for quality calibration. Also, a reduced-reference VQA algorithm is proposed to predict the local factors from the source video. In the IRCCyN/IVC video database of content influence and the LIVE mobile video database, the performance of VQA algorithms is improved significantly by local alignment. The proposed mapping strategy with prediction of local factors outperforms one no-reference VQA metric and is comparable to one full-reference VQA metric. Thus predicting the local factors in local alignment based on video content will be a promising new approach for VQA.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    Evaluating complex scales through subjective ranking

    2014 Sixth International Workshop on Quality of Multimedia Experience (QoMEX)

    2014

    Abstract anzeigen

    In this paper, a subjective assessment methodology based on ranking, reordering and image categorization is proposed. It is designed to facilitate the evaluation of complex features such as monocular depth cues in natural images. These features can be particularly challenging to explain to test participants, and the proposed methodology is designed to provide to the test participants more insights and examples about the scale under evaluation. The performances of the method are compared to the absolute category rating methodology, and the advantages of each part of the test design are studied to verify the added value of the different steps of the evaluation procedure. Results show that the method is promising and can improve stability between subjective test participant results.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    J. Li, Y. Koudota, Marcus Barkowsky, H. Primon, P. Le Callet

    Comparing Upscaling Algorithms From Hd To Ultra Hd By Evaluating Preference Of Experience

    2014 Sixth International Workshop on Quality of Multimedia Experience (QoMEX)

    2014

    Abstract anzeigen

    As the next generation of TV, Ultra High Definition Television (UHDTV) is attracting more and more people's attention as it provides a new viewing experience. Considering content delivery, due to the lack of Ultra HD resources, a direct question for the industry is that whether the state-of-the-art upscaling algorithms can be utilized to upscale the current HD or Full HD resources to UHD, gaining benefit from the higher resolution but without losing the high quality viewing experience. To investigate this, in this study, we upscaled 720p and 1080p sequences to UHD resolution by different upscaling algorithms. Paired Comparison methodology was used in the subjective experiment to evaluate their performances. The results showed that for the case of fast motion content, viewers' preference on different upscaled video sequences is not significantly different. In general conditions, the low complexity upscaling algorithms (e.g., lanczos-3) performed better than the high complexity algorithms (e.g., Robust Super Resolution algorithm). A novel upscaling algorithm adapted to UHD is recommended to be developed based on the mechanisms of human visual system.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    Chapter 20: 3D Video

    Quality of Experience: Advanced Concepts, Applications and Methods

    2014

    ISBN: 978-3-319-02680-0

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    J. Li, Marcus Barkowsky, P. Le Callet

    Assessing the Quality of Experience of 3DTV and Beyond: Tackling the Multidimensional Sensation

    3D Future Internet Media, New York

    2014

    ISBN: 978-1-4614-8372-4

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    Measuring perceived depth in natural images and study of its relation with monocular and binocular depth cues

    Proceedings of SPIE Vol. 9011: IS&T/SPIE Electronic Imaging Stereoscopic Displays and Applications XXV , San Francisco, CA, USA

    2014

    Abstract anzeigen

    The perception of depth in images and video sequences is based on different depth cues. Studies have considered depth perception threshold as a function of viewing distance (Cutting & Vishton,1995), the combination of different monocular depth cues and their quantitative relation with binocular depth cues and their different possible type of interactions (Landy,1995). But these studies only consider artificial stimuli and none of them attempts to provide a quantitative contribution of monocular and binocular depth cues compared to each other in the specific context of natural images. This study targets this particular application case. The evaluation of the strength of different depth cues compared to each other using a carefully designed image database to cover as much as possible different combinations of monocular (linear perspective, texture gradient, relative size and defocus blur) and binocular depth cues. The 200 images were evaluated in two distinct subjective experiments to evaluate separately perceived depth and different monocular depth cues. The methodology and the description of the definition of the different scales will be detailed. The image database is also released for the scientific community.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    J. Li, Marcus Barkowsky, P. Callet

    Visual discomfort of stereoscopic 3D videos: Influence of 3D motion

    Displays, vol. 35, no. 1, pp. 49-57

    2014

    DOI: 10.1016/j.displa.2014.01.002

    Abstract anzeigen

    Visual discomfort is one of the most frequent complaints of the viewers while watching 3D images and videos. Large disparity and large amount of motion are two main causes of visual discomfort. To quantify this influence, three objectives are set in this paper. The first one is the comparative analysis on the influence of different types of motion, i.e., static stereoscopic image, planar motion and in-depth motion, on visual discomfort. The second one is the investigation on the influence factors for each motion type, for example, the disparity offset, the disparity amplitude and velocity. The third one is to propose an objective model for visual discomfort. Thirty-six synthetic stereoscopic video stimuli with different types of motion are used in this study. In the subjective test, an efficient paired comparison method called Adaptive Square Design (ASD) was used to reduce the number of comparisons for each observer and keep the results reliable. The experimental results showed that motion does not always induce more visual discomfort than static conditions. The in-depth motion generally induces more visual discomfort than the planar motion. The relative disparity between the foreground and the background, and the motion velocity are identified as main factors for visual discomfort. According to the subjective results, an objective model for comparing visual discomfort induced by different types of motion is proposed which shows high correlation with the subjective perception.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    P. Le Callet, Marcus Barkowsky

    On viewing distance and visual quality assessment in the age of Ultra High Definition TV

    VQEG (Video Quality Expert Group) eLetter, vol. 1, no. 1, pp. 25-30

    2014

    Abstract anzeigen

    The consumer video market is largely driven by the introduction of new formats(e.g.,new pixel resolution). Each time,the story remains the same: what is the optimal viewing distance? Ultra High Definition TV is not an exception. This simple question is of crucial importance when it comes to the issue of quality and the added value of a new technology. In this letter, werevisit the topic,starting from bestpractices and then raising open questions.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    J. Li, Marcus Barkowsky, P. Le Callet

    Validation of reliable 3DTV subjective assessment methodology ‐ Establishing a Ground Truth Database

    VQEG (Video Quality Expert Group) eLetter, vol. 1, no. 2

    2014

    Abstract anzeigen

    Quality of Experience (QoE) in 3DTV is a multi-dimensional concept which includes image quality, depth quality, and visual comfort. How to measure this multi-dimensional concept is a challenging issue nowadays. In this letter, we introduce a Ground Truth database which is targeted for the standardization of subjective methodologies for QoE in 3DTV.

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    G. van Wallendael, N. Staelens, E. Masala, L. Janowski, K. Berger, Marcus Barkowsky

    Dreamed about training, verifying and validating your QoE model on a million videos?

    VQEG (Video Quality Expert Group) eLetter, vol. 1, no. 2, pp. 19-29

    2014

    DigitalF: Angewandte Informatik

    Zeitschriftenartikel

    Marcus Barkowsky, I. Sedano, K. Brunnström, M. Leszczuk, N. Staelens

    Hybrid video quality prediction: reviewing video quality measurement for widening application scope

    Multimedia Tools and Applications, vol. 74, pp. 323-343

    2014

    DOI: 10.1007/s11042-014-1978-2

    Abstract anzeigen

    A tremendous number of objective video quality measurement algorithms have been developed during the last two decades. Most of them either measure a very limited aspect of the perceived video quality or they measure broad ranges of quality with limited prediction accuracy. This paper lists several perceptual artifacts that may be computationally measured in an isolated algorithm and some of the modeling approaches that have been proposed to predict the resulting quality from those algorithms. These algorithms usually have a very limited application scope but have been verified carefully. The paper continues with a review of some standardized and well-known video quality measurement algorithms that are meant for a wide range of applications, thus have a larger scope. Their individual artifacts prediction accuracy is usually lower but some of them were validated to perform sufficiently well for standardization. Several difficulties and shortcomings in developing a general purpose model with high prediction performance are identified such as a common objective quality scale or the behavior of individual indicators when confronted with stimuli that are out of their prediction scope. The paper concludes with a systematic framework approach to tackle the development of a hybrid video quality measurement in a joint research collaboration.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

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

    Subjective and objective evaluation of an audiovisual subjective dataset for research and development

    2013 Fifth International Workshop on Quality of Multimedia Experience (QoMEX)

    2013

    Abstract anzeigen

    In 2011, the Video Quality Experts Group (VQEG) ran subjects through the same audiovisual subjective test at six different international laboratories. That small dataset is now publically available for research and development purposes.

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Marcus Barkowsky, K. Brunnström, T. Ebrahimi, L. Karam, P. Lebreton, P. Le Callet, A. Perkis, A. Raake, M. Subedar, K. Wang, L. Xing, J. You

    Subjective and Objective Visual Quality Assessment in the Context of Stereoscopic 3D-TV

    3D-TV System with Depth-Image-Based Rendering

    2013

    ISBN: 978-1-4419-9963-4

    DOI: 10.1007/978-1-4419-9964-1_14

    DigitalF: Angewandte Informatik

    Beitrag (Sammelband oder Tagungsband)

    Marcus Barkowsky, N. Staelens, L. Janowski

    Open collaboration on hybrid video quality models ‐ VQEG joint effort group hybrid

    2013 IEEE 15th International Workshop on Multimedia Signal Processing (MMSP)

    2013

    Abstract anzeigen

    Several factors limit the advances on automatizing video quality measurement. Modelling the human visual system requires multi- and interdisciplinary efforts. A joint effort may bridge the large gap between the knowledge required in conducting a psychophysical experiment on isolated visual stimuli to engineering a universal model for video quality estimation under real-time constraints. The verification and validation requires input reaching from professional content production to innovative machine learning algorithms. Our paper aims at highlighting the complex interactions and the multitude of open questions as well as industrial requirements that led to the creation of the Joint Effort Group in the Video Quality Experts Group. The paper will zoom in on the first activity, the creation of a hybrid video quality model.