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Auflistung nach Autor:in "Nowak, Stefanie"

1 - 3 von 3
  • Konferenzbeitrag
    An automated 4D approach for left ventricular assessment in clinical cine MR images
    (INFORMATIK 2006 – Informatik für Menschen, Band 1, 2006) Wesarg, Stefan; Nowak, Stefanie
    Cine Magnetic Resonance (MR) imaging has become the method-of-choice for the examination of the dynamic behaviour of the heart. An assessment of the left ventricle can reveal regions of myocardial dysfunction and their severeness. The scope of this work is a complete analysis of the left ventricular dynamics for the usage in a clinical environment. For that purpose, endocardial and epicardial borders are automatically extracted in 3D cine data in a first step. This is followed by a segmentation of the endocardium and the myocardium into 17 segments following the recommendations of the American Heart Association and the computation of common global volumetric values (stroke volume, ejection fraction etc.) and parameters that describe the left ventricular dynamics (wall motion, wall thickening). A retrospective analysis of cardiac cine MR image data from 20 patients (healthy ones, patients with abnormal wall motion, and patients who suffered an infarction) has been done. That image data has been acquired in the clinical routine at two different hospitals. The here presented automated approach led to a successful segmentation and assessment of the left ventricle for all data sets. The pathological cases could be identified easily due to their characteristic change of the motion pattern. The main advantage of our approach is the reproducibility of the assessment results and the gain in time for the cardiologist who has to analyse the huge amount of cine data.
  • Konferenzbeitrag
    Automated Classification of Film Scenes based on Film Grammar
    (Workshop Audiovisuelle Medien WAM 2010, 2010) Lanz, Cornelia; Lukashevich, Hanna; Nowak, Stefanie
    Whenever there are extensive data collections to handle, metadata can help to structure and simplify this task. On websites for Video on Demand services or for film recommendations, we often find tags to describe and to search for films. However, manual tagging of films is a time-consuming task with a strong demand for human resources. In this paper, we present an approach for automated classification and indexing of film scenes. Although the classification algorithm uses audiovisual information, we mainly focus on visual information. The conception of the visual features is based on film grammar. In order to cover multiple aspects of film grammar, we enrich the row of state-of-the-art visual features by several novel ones. The evaluation of the classification framework is performed on five categories Suspense, Interaction, Essential Features, Dynamic and Valence. Altogether, the best classification rate equals an accuracy of 83.60% for the classification of the amount of dynamics in film scenes.
  • Konferenzbeitrag
    Evaluation of an Image and Music Indexing Prototype
    (Workshop Audiovisuelle Medien WAM 2009, 2009) Dunker, Peter; Paduschek, Ronny; Dittmar, Christian; Nowak, Stefanie; Gruhne, Matthias
    This paper describes a technical solution for automated semantic indexing of music and images for a media archive environment. The indexing is based on a multi-modal low-level feature extraction and semantic high-level feature classification such as mood, genre, daytime or visual scene types. The classification on both, the audio and the visual information is based on a generic machine learning core architecture. A combination and cleansing process validates for improving the classification results. This paper presents the technical realization of a prototype and its corresponding evaluation. Finally, the practical relevance of this technology results, based on the findings of the evaluation is discussed.