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  1. Book ; Online: Multi-Channel Cross Modal Detection of Synthetic Face Images

    Ibsen, M. / Rathgeb, C. / Marcel, S. / Busch, C.

    2023  

    Abstract: Synthetically generated face images have shown to be indistinguishable from real images by humans and as such can lead to a lack of trust in digital content as they can, for instance, be used to spread misinformation. Therefore, the need to develop ... ...

    Abstract Synthetically generated face images have shown to be indistinguishable from real images by humans and as such can lead to a lack of trust in digital content as they can, for instance, be used to spread misinformation. Therefore, the need to develop algorithms for detecting entirely synthetic face images is apparent. Of interest are images generated by state-of-the-art deep learning-based models, as these exhibit a high level of visual realism. Recent works have demonstrated that detecting such synthetic face images under realistic circumstances remains difficult as new and improved generative models are proposed with rapid speed and arbitrary image post-processing can be applied. In this work, we propose a multi-channel architecture for detecting entirely synthetic face images which analyses information both in the frequency and visible spectra using Cross Modal Focal Loss. We compare the proposed architecture with several related architectures trained using Binary Cross Entropy and show in cross-model experiments that the proposed architecture supervised using Cross Modal Focal Loss, in general, achieves most competitive performance.
    Keywords Computer Science - Computer Vision and Pattern Recognition
    Subject code 006
    Publishing date 2023-11-28
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: Simple technique of determining the fibre diameter during etching.

    Namiq, Medya F / Ibsen, Morten

    Optics express

    2019  Volume 26, Issue 25, Page(s) 32908–32917

    Abstract: We present a technique to measure, in situ, the diameter of an optical fibre during etching using a fibre Bragg grating (FBG). Differential shifts between the fundamental mode, and the higher-order Bragg resonances generated by the etching process are ... ...

    Abstract We present a technique to measure, in situ, the diameter of an optical fibre during etching using a fibre Bragg grating (FBG). Differential shifts between the fundamental mode, and the higher-order Bragg resonances generated by the etching process are used to determine the diameter of a standard optical fibre (SMF28) with a precision of ~200nm. Numerical simulations are also carried out to investigate the overlap of the evanescent field of the fundamental mode and higher-order modes (LP11, LP02, LP21 and LP12). These simulations were used to find and calibrate the diameter of the etched-cladding fibre. Subsequently, the technique was used to experimentally determine the refractive index of two buffered hydrofluoric (BHF) acid solutions, (20:1) and (7:1), to be ~1.360 ± 0.005 and ~1.370 ± 0.005 respectively @ ~1550nm. The refractive index of both BHF solutions is calibrated against known indices of liquids and solvents, including deionised water, methanol, acetone, ethanol, isopropanol, and ethylene glycol. The numerical simulations and experimental results are in very good agreement. We believe the approach presented in this work provides a controlled technique to achieve precise target diameter of the etched fibres in real time.
    Language English
    Publishing date 2019-01-15
    Publishing country United States
    Document type Journal Article
    ZDB-ID 1491859-6
    ISSN 1094-4087 ; 1094-4087
    ISSN (online) 1094-4087
    ISSN 1094-4087
    DOI 10.1364/OE.26.032908
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Book ; Online: Child Face Recognition at Scale

    Falkenberg, Magnus / Ottsen, Anders Bensen / Ibsen, Mathias / Rathgeb, Christian

    Synthetic Data Generation and Performance Benchmark

    2023  

    Abstract: We address the need for a large-scale database of children's faces by using generative adversarial networks (GANs) and face age progression (FAP) models to synthesize a realistic dataset referred to as HDA-SynChildFaces. To this end, we proposed a ... ...

    Abstract We address the need for a large-scale database of children's faces by using generative adversarial networks (GANs) and face age progression (FAP) models to synthesize a realistic dataset referred to as HDA-SynChildFaces. To this end, we proposed a processing pipeline that initially utilizes StyleGAN3 to sample adult subjects, which are subsequently progressed to children of varying ages using InterFaceGAN. Intra-subject variations, such as facial expression and pose, are created by further manipulating the subjects in their latent space. Additionally, the presented pipeline allows to evenly distribute the races of subjects, allowing to generate a balanced and fair dataset with respect to race distribution. The created HDA-SynChildFaces consists of 1,652 subjects and a total of 188,832 images, each subject being present at various ages and with many different intra-subject variations. Subsequently, we evaluates the performance of various facial recognition systems on the generated database and compare the results of adults and children at different ages. The study reveals that children consistently perform worse than adults, on all tested systems, and the degradation in performance is proportional to age. Additionally, our study uncovers some biases in the recognition systems, with Asian and Black subjects and females performing worse than White and Latino Hispanic subjects and males.
    Keywords Computer Science - Computer Vision and Pattern Recognition
    Subject code 410
    Publishing date 2023-04-23
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Book: Internet Technologien

    Ibsen, Michael

    berufsbegleitender Bachelorstudiengang of Engineering in Elektro- und Informationstechnik

    (Schriften des Berufsbegleitenden Studiengangs Elektro- und Informationstechnik)

    2015  

    Title variant Elektrotechnik
    Author's details von: Michael Ibsen
    Series title Schriften des Berufsbegleitenden Studiengangs Elektro- und Informationstechnik
    Language German
    Size 114 S., Ill., graph. Darst.
    Edition Version: 1.0, 1. Aufl.
    Publisher Elektro- und Informationstechnik (B. Eng.), Hochschule Aschaffenburg u.a.
    Publishing place Aschaffenburg
    Document type Book
    Note Förderkennzeichen BMBF 16OH11054. - Verbund-Nr. 01105545
    Database Library catalogue of the German National Library of Science and Technology (TIB), Hannover

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  5. Book ; Online: Face Beneath the Ink

    Ibsen, Mathias / Rathgeb, Christian / Drozdowski, Pawel / Busch, Christoph

    Synthetic Data and Tattoo Removal with Application to Face Recognition

    2022  

    Abstract: Systems that analyse faces have seen significant improvements in recent years and are today used in numerous application scenarios. However, these systems have been found to be negatively affected by facial alterations such as tattoos. To better ... ...

    Abstract Systems that analyse faces have seen significant improvements in recent years and are today used in numerous application scenarios. However, these systems have been found to be negatively affected by facial alterations such as tattoos. To better understand and mitigate the effect of facial tattoos in facial analysis systems, large datasets of images of individuals with and without tattoos are needed. To this end, we propose a generator for automatically adding realistic tattoos to facial images. Moreover, we demonstrate the feasibility of the generation by using a deep learning-based model for removing tattoos from face images. The experimental results show that it is possible to remove facial tattoos from real images without degrading the quality of the image. Additionally, we show that it is possible to improve face recognition accuracy by using the proposed deep learning-based tattoo removal before extracting and comparing facial features.
    Keywords Computer Science - Computer Vision and Pattern Recognition
    Subject code 006
    Publishing date 2022-02-10
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Industrial ion-exchange chromatography development using discontinuous Galerkin methods coupled with forward sensitivity analysis.

    Meyer, Kristian / Søes Ibsen, Mikkel / Vetter-Joss, Lisa / Broberg Hansen, Ernst / Abildskov, Jens

    Journal of chromatography. A

    2022  Volume 1689, Page(s) 463741

    Abstract: In this work, a discontinuous Galerkin method coupled with forward sensitivity analysis (DG-FSA) is presented. The DG-FSA method is used to reduce computational cost required for model-based ion-exchange chromatography development using industrial load ... ...

    Abstract In this work, a discontinuous Galerkin method coupled with forward sensitivity analysis (DG-FSA) is presented. The DG-FSA method is used to reduce computational cost required for model-based ion-exchange chromatography development using industrial load samples. As an example, the design of an anion-exchange chromatography step is considered. This step is used to purify an experimental peptide product called Protein G from Novo Nordisk A/S (Bagsværd, Denmark). The results demonstrate, that a fourth order DG-FSA method can reduce computational cost of inverse problems by a factor ×16 compared to a second (low) order DG-FSA method. Furthermore, the fourth-order DG-FSA method enable the computation of probability distributions of optimized processing conditions given uncertainty in model parameters or inputs. This analysis is not possible within a reasonable timeframe when applying the second (low) order DG-FSA method. The design procedure facilitates the optimization of the Protein G purification step. In an experimental validation run, the productivity is increased by 70% while sacrificing 4% yield at a similar purity constraint compared to an experiment with baseline performance.
    MeSH term(s) Chromatography, Ion Exchange/methods ; Chromatography, High Pressure Liquid ; Uncertainty ; Chromatography, Affinity ; Anions
    Chemical Substances Anions
    Language English
    Publishing date 2022-12-23
    Publishing country Netherlands
    Document type Journal Article
    ZDB-ID 1171488-8
    ISSN 1873-3778 ; 0021-9673
    ISSN (online) 1873-3778
    ISSN 0021-9673
    DOI 10.1016/j.chroma.2022.463741
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    In stock of ZB MED Cologne/Königswinter

    Zs.A 813: Show issues Location:
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    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
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  7. Book ; Online: Attacking Face Recognition with T-shirts

    Ibsen, M. / Rathgeb, C. / Brechtel, F. / Klepp, R. / Pöppelmann, K. / George, A. / Marcel, S. / Busch, C.

    Database, Vulnerability Assessment and Detection

    2022  

    Abstract: Face recognition systems are widely deployed for biometric authentication. Despite this, it is well-known that, without any safeguards, face recognition systems are highly vulnerable to presentation attacks. In response to this security issue, several ... ...

    Abstract Face recognition systems are widely deployed for biometric authentication. Despite this, it is well-known that, without any safeguards, face recognition systems are highly vulnerable to presentation attacks. In response to this security issue, several promising methods for detecting presentation attacks have been proposed which show high performance on existing benchmarks. However, an ongoing challenge is the generalization of presentation attack detection methods to unseen and new attack types. To this end, we propose a new T-shirt Face Presentation Attack (TFPA) database of 1,608 T-shirt attacks using 100 unique presentation attack instruments. In an extensive evaluation, we show that this type of attack can compromise the security of face recognition systems and that some state-of-the-art attack detection mechanisms trained on popular benchmarks fail to robustly generalize to the new attacks. Further, we propose three new methods for detecting T-shirt attack images, one which relies on the statistical differences between depth maps of bona fide images and T-shirt attacks, an anomaly detection approach trained on features only extracted from bona fide RGB images, and a fusion approach which achieves competitive detection performance.
    Keywords Computer Science - Computer Vision and Pattern Recognition
    Subject code 006
    Publishing date 2022-11-14
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  8. Article: Long-Term Violent Reoffending Following Forensic Psychiatric Treatment: Comparing Forensic Psychiatric Examinees and General Offender Controls.

    Bengtson, Susanne / Lund, Jens / Ibsen, Michael / Långström, Niklas

    Frontiers in psychiatry

    2019  Volume 10, Page(s) 715

    Abstract: Background: ...

    Abstract Background:
    Language English
    Publishing date 2019-10-16
    Publishing country Switzerland
    Document type Journal Article
    ZDB-ID 2564218-2
    ISSN 1664-0640
    ISSN 1664-0640
    DOI 10.3389/fpsyt.2019.00715
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Book ; Online: Impact of Facial Tattoos and Paintings on Face Recognition Systems

    Ibsen, Mathias / Rathgeb, Christian / Fink, Thomas / Drozdowski, Pawel / Busch, Christoph

    2021  

    Abstract: In the past years, face recognition technologies have shown impressive recognition performance, mainly due to recent developments in deep convolutional neural networks. Notwithstanding those improvements, several challenges which affect the performance ... ...

    Abstract In the past years, face recognition technologies have shown impressive recognition performance, mainly due to recent developments in deep convolutional neural networks. Notwithstanding those improvements, several challenges which affect the performance of face recognition systems remain. In this work, we investigate the impact that facial tattoos and paintings have on current face recognition systems. To this end, we first collected an appropriate database containing image-pairs of individuals with and without facial tattoos or paintings. The assembled database was used to evaluate how facial tattoos and paintings affect the detection, quality estimation, as well as the feature extraction and comparison modules of a face recognition system. The impact on these modules was evaluated using state-of-the-art open-source and commercial systems. The obtained results show that facial tattoos and paintings affect all the tested modules, especially for images where a large area of the face is covered with tattoos or paintings. Our work is an initial case-study and indicates a need to design algorithms which are robust to the visual changes caused by facial tattoos and paintings.

    Comment: Accepted to IET Biometrics
    Keywords Computer Science - Computer Vision and Pattern Recognition
    Subject code 410
    Publishing date 2021-03-17
    Publishing country us
    Document type Book ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  10. Article ; Online: How late in pregnancy can fetal physiological omphalocele be seen? Nationwide study of cases in Denmark over 4-year period.

    Hornstrup, L S / Kristensen, S E / Nørgaard, P / Sperling, L / Sandager, P / Ibsen, M H / Jørgensen, F S

    Ultrasound in obstetrics & gynecology : the official journal of the International Society of Ultrasound in Obstetrics and Gynecology

    2022  Volume 60, Issue 3, Page(s) 428–429

    MeSH term(s) Denmark/epidemiology ; Female ; Fetus ; Hernia, Umbilical/diagnostic imaging ; Hernia, Umbilical/epidemiology ; Humans ; Pregnancy ; Prenatal Care ; Retrospective Studies ; Ultrasonography, Prenatal
    Language English
    Publishing date 2022-10-19
    Publishing country England
    Document type Letter
    ZDB-ID 1073183-0
    ISSN 1469-0705 ; 0960-7692
    ISSN (online) 1469-0705
    ISSN 0960-7692
    DOI 10.1002/uog.24937
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    In stock of ZB MED Cologne/Königswinter

    Zs.A 3214: Show issues Location:
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