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  1. Article ; Online: Underwater 3D Scanning System for Cultural Heritage Documentation

    Christian Bräuer-Burchardt / Christoph Munkelt / Michael Bleier / Matthias Heinze / Ingo Gebhart / Peter Kühmstedt / Gunther Notni

    Remote Sensing, Vol 15, Iss 1864, p

    2023  Volume 1864

    Abstract: Three-dimensional capturing of underwater archeological sites or sunken shipwrecks can support important documentation purposes. In this study, a novel 3D scanning system based on structured illumination is introduced, which supports cultural heritage ... ...

    Abstract Three-dimensional capturing of underwater archeological sites or sunken shipwrecks can support important documentation purposes. In this study, a novel 3D scanning system based on structured illumination is introduced, which supports cultural heritage documentation and measurement tasks in underwater environments. The newly developed system consists of two monochrome measurement cameras, a projection unit that produces aperiodic sinusoidal fringe patterns, two flashlights, a color camera, an inertial measurement unit (IMU), and an electronic control box. The opportunities and limitations of the measurement principles of the 3D scanning system are discussed and compared to other 3D recording methods such as laser scanning, ultrasound, and photogrammetry, in the context of underwater applications. Some possible operational scenarios concerning cultural heritage documentation are introduced and discussed. A report on application activities in water basins and offshore environments including measurement examples and results of the accuracy measurements is given. The study shows that the new 3D scanning system can be used for both the topographic documentation of underwater sites and to generate detailed true-scale 3D models including the texture and color information of objects that must remain under water.
    Keywords underwater 3D scanning ; structured light illumination ; object reconstruction ; 3D model generation ; site mapping ; Science ; Q
    Subject code 620
    Language English
    Publishing date 2023-03-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article ; Online: A New Sensor System for Accurate 3D Surface Measurements and Modeling of Underwater Objects

    Christian Bräuer-Burchardt / Christoph Munkelt / Michael Bleier / Matthias Heinze / Ingo Gebhart / Peter Kühmstedt / Gunther Notni

    Applied Sciences, Vol 12, Iss 4139, p

    2022  Volume 4139

    Abstract: A new underwater 3D scanning device based on structured illumination and designed for continuous capture of object data in motion for deep sea inspection applications is introduced. The sensor permanently captures 3D data of the inspected surface and ... ...

    Abstract A new underwater 3D scanning device based on structured illumination and designed for continuous capture of object data in motion for deep sea inspection applications is introduced. The sensor permanently captures 3D data of the inspected surface and generates a 3D surface model in real time. Sensor velocities up to 0.7 m/s are directly compensated while capturing camera images for the 3D reconstruction pipeline. The accuracy results of static measurements of special specimens in a water basin with clear water show the high accuracy potential of the scanner in the sub-millimeter range. Measurement examples with a moving sensor show the significance of the proposed motion compensation and the ability to generate a 3D model by merging individual scans. Future application tests in offshore environments will show the practical potential of the sensor for the desired inspection tasks.
    Keywords optical underwater 3D sensor ; structured illumination ; motion compensation ; 3D model generation ; high-accuracy 3D measurements ; Technology ; T ; Engineering (General). Civil engineering (General) ; TA1-2040 ; Biology (General) ; QH301-705.5 ; Physics ; QC1-999 ; Chemistry ; QD1-999
    Subject code 620
    Language English
    Publishing date 2022-04-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  3. Article ; Online: Electronic cleansing of tagged residue in CT colonography

    Thomas Mang / Christian Bräuer / Stefaan Gryspeerdt / Martina Scharitzer / Helmut Ringl / Philippe Lefere

    Insights into Imaging, Vol 11, Iss 1, Pp 1-

    what radiologists need to know

    2020  Volume 12

    Abstract: Abstract CT colonography (CTC) is the radiological examination of choice for the diagnosis of colorectal neoplasia. Faecal tagging is considered a mandatory part of bowel preparation. However, the colonic mucosa, obscured by tagged residue, is not ... ...

    Abstract Abstract CT colonography (CTC) is the radiological examination of choice for the diagnosis of colorectal neoplasia. Faecal tagging is considered a mandatory part of bowel preparation. However, the colonic mucosa, obscured by tagged residue, is not accessible to endoluminal 3D views and requires time-consuming 2D evaluation. Electronic cleansing (EC) software algorithms can overcome this limitation by digitally subtracting tagged residue from the colonic lumen. Ideally, this enables a seamless 3D endoluminal evaluation. Despite this benefit, EC is a potential source of a wide range of artefacts. Accurate EC requires proper CTC examination technique and faecal tagging. The digital subtraction process has been shown to affect the relevant morphological features of both colonic anatomy and colonic lesions, if submerged under faecal residue. This article summarises the potential effects of EC on CTC imaging, the consequences for reporting and patient management, and strategies to avoid pitfalls. Furthermore, potentially negative effects on clinical reporting and patient management are shown, and problem-solving techniques, as well as recommendations for the appropriate use of EC techniques, are presented. Radiologists using EC should be familiar with EC-related effects on polyp size and also with correct measurement techniques.
    Keywords CT colonography ; Virtual colonoscopy ; Electronic cleansing ; Faecal tagging ; Colorectal polyps ; Medical physics. Medical radiology. Nuclear medicine ; R895-920
    Language English
    Publishing date 2020-03-01T00:00:00Z
    Publisher SpringerOpen
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Enhancing Anticoagulation Monitoring and Therapy in Patients Undergoing Microvascular Reconstruction in Maxillofacial Surgery

    Tom A. Schröder / Henry Leonhardt / Dominik Haim / Christian Bräuer / Kiriaki K. Papadopoulos / Oliver Vicent / Andreas Güldner / Martin Mirus / Jürgen Schmidt / Hanns C. Held / Oliver Tiebel / Thomas Birkner / Jan Beyer-Westendorf / Günter Lauer / Peter M. Spieth / Thea Koch / Lars Heubner

    Journal of Personalized Medicine, Vol 12, Iss 8, p

    A Prospective Observational Trial

    2022  Volume 1229

    Abstract: Background: In reconstructive surgery, loss of a microvascular free flap due to perfusion disorders, especially thrombosis, is a serious complication. In recent years, viscoelastic testing (VET) has become increasingly important in point-of-care (POC) ... ...

    Abstract Background: In reconstructive surgery, loss of a microvascular free flap due to perfusion disorders, especially thrombosis, is a serious complication. In recent years, viscoelastic testing (VET) has become increasingly important in point-of-care (POC) anticoagulation monitoring. This paper describes a protocol for enhanced anticoagulation monitoring during maxillofacial flap surgery. Objective: The aim of the study will be to evaluate, in a controlled setting, the predictive value of POC devices for the type of flap perfusion disorders due to thrombosis or bleeding. VET, Platelet monitoring (PM) and standard laboratory tests (SLT) are comparatively examined. Methods/Design: This study is an investigator-initiated prospective trial in 100 patients undergoing maxillofacial surgery. Patients who undergo reconstructive surgery using microvascular-free flaps will be consecutively enrolled in the study. All patients provide blood samples for VET, PM and SLT at defined time points. The primary outcome is defined as free flap loss during the hospital stay. Statistical analyses will be performed using t-tests, including the Bonferroni adjustment for multiple comparisons. Discussion: This study will help clarify whether VET can improve individualized patient care in reconstruction surgery. A better understanding of coagulation in relation to flap perfusion disorders may allow real-time adaption of antithrombotic strategies and potentially prevent flap complications.
    Keywords coagulation monitoring ; viscoelastic testing ; maxillofacial surgery ; free flap thrombosis ; point-of-care coagulation ; Medicine ; R
    Subject code 610
    Language English
    Publishing date 2022-07-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article ; Online: Underwater 3D Surface Measurement Using Fringe Projection Based Scanning Devices

    Christian Bräuer-Burchardt / Matthias Heinze / Ingo Schmidt / Peter Kühmstedt / Gunther Notni

    Sensors, Vol 16, Iss 1, p

    2015  Volume 13

    Abstract: In this work we show the principle of optical 3D surface measurements based on the fringe projection technique for underwater applications. The challenges of underwater use of this technique are shown and discussed in comparison with the classical ... ...

    Abstract In this work we show the principle of optical 3D surface measurements based on the fringe projection technique for underwater applications. The challenges of underwater use of this technique are shown and discussed in comparison with the classical application. We describe an extended camera model which takes refraction effects into account as well as a proposal of an effective, low-effort calibration procedure for underwater optical stereo scanners. This calibration technique combines a classical air calibration based on the pinhole model with ray-based modeling and requires only a few underwater recordings of an object of known length and a planar surface. We demonstrate a new underwater 3D scanning device based on the fringe projection technique. It has a weight of about 10 kg and the maximal water depth for application of the scanner is 40 m. It covers an underwater measurement volume of 250 mm × 200 mm × 120 mm. The surface of the measurement objects is captured with a lateral resolution of 150 μm in a third of a second. Calibration evaluation results are presented and examples of first underwater measurements are given.
    Keywords underwater 3D-scanner ; fringe projection ; underwater stereo camera calibration ; Technology (General) ; T1-995 ; Technology ; T ; Analytical chemistry ; QD71-142 ; Chemistry ; QD1-999 ; Science ; Q
    Subject code 620 ; 600
    Language English
    Publishing date 2015-12-01T00:00:00Z
    Publisher MDPI AG
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  6. Article ; Online: Rectificación Monocular de Imágenes

    Klaus Voss / Christian Bräuer Burchardt

    Computación y Sistemas, Vol 4, Iss 3, Pp 249-

    2001  Volume 263

    Keywords Electronic computers. Computer science ; QA75.5-76.95 ; Instruments and machines ; QA71-90 ; Mathematics ; QA1-939 ; Science ; Q
    Language English
    Publishing date 2001-01-01T00:00:00Z
    Publisher Instituto Politécnico Nacional
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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