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Auflistung nach Autor:in "Hofbauer, Heinz"

1 - 5 von 5
  • Konferenzbeitrag
    Image metric-based biometric comparators: a supplement to feature vector-based Hamming distance?
    (BIOSIG 2012, 2012) Hofbauer, Heinz; Rathgeb, Christian; Uhl, Andreas; Wild, Peter
    In accordance with the ISO/IEC FDIS 19794-6 standard an iris-biometric fusion of image metric-based and Hamming distance (HD) comparison scores is presented. In order to demonstrate the applicability of a knowledge transfer from image quality assessment to iris recognition, Peak Signal to Noise Ratio (PSNR), Structural Similarity Index Measure (SSIM), Local Edge Gradients metric (LEG), Edge Similarity Score (ESS), Local Feature Based Visual Security (LFBVS), and Visual Information Fidelity (VIF) are applied to iris textures, i.e. query textures are interpreted as noisy representations of registered ones. Obtained scores are fused with traditional HD scores obtained from iris-codes generated by different feature extraction algorithms. Experimental evaluations on the CASIA-v3 iris database confirm the soundness of the proposed approach.
  • Konferenzbeitrag
    Investigation of better portable graphics compression for iris biometric recognition
    (BIOSIG 2015, 2015) Hofbauer, Heinz; Rathgeb, Christian; Wagner, Johannes; Uhl, Andreas; Busch, Christoph
    In this paper we present the very first study on the effectiveness of the recently proposed Better Portable Graphics (BPG) image compression algorithm in the context of iris recognition. Original and pre-processed iris images of the IITDv1 iris database are compressed at various reasonable bitrates and the impact of BPG on recognition accuracy is estimated in a bilateral and unilateral compression scenario. In experiments we found that, compared to well-established image compression standards recommended for biometric data interchange, JPEG and JPEG 2000, BPG generally reveals the least impact on the recognition accuracy of two conventional feature extraction techniques. In addition, we observe that iris segmentation is least affected when employing BPG compression. Consequentially, we identify BPG as an adequate choice for image compression in iris recognition.
  • Konferenzbeitrag
    Isolating iris template ageing in a semi-controlled environment
    (Biosig 2016, 2016) Hofbauer, Heinz; Tomeo-Reyes, Inmaculada; Uhl, Andreas
  • Konferenzbeitrag
    Segmentation-level fusion for iris recogntion
    (BIOSIG 2015, 2015) Wild, Peter; Hofbauer, Heinz; Ferryman, James; Uhl, Andreas
    This paper investigates the potential of fusion at normalisation/segmentation level prior to feature extraction. While there are several biometric fusion methods at data/feature level, score level and rank/decision level combining raw biometric signals, scores, or ranks/decisions, this type of fusion is still in its infancy. However, the increasing demand to allow for more relaxed and less invasive recording conditions, especially for on-the-move iris recognition, suggests to further investigate fusion at this very low level. This paper focuses on the approach of multi-segmentation fusion for iris biometric systems investigating the benefit of combining the segmentation result of multiple normalisation algorithms, using four methods from two different public iris toolkits (USIT, OSIRIS) on the public CASIA and IITD iris datasets. Evaluations based on recognition accuracy and ground truth segmentation data indicate high sensitivity with regards to the type of errors made by segmentation algorithms.
  • Textdokument
    Visuelle Evaluierung, Skalierung und Transport von sicheren Videos
    (Ausgezeichnete Informatikdissertationen 2013, 2014) Hofbauer, Heinz