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Suche nach „[U.] [Engelke]“ hat 4 Publikationen gefunden
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    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)

    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)

    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