3D Skeleton based Head Detection and Tracking using Range Images

in IEEE Transactions on Vehicular Technology (2009), 58(8), 4064-4077

Vision-based 3-D head detection and tracking systems have been studied in several applications like video surveillance, face-detection systems, and occupant posture analysis. In this paper, we present the ... [more ▼]

Vision-based 3-D head detection and tracking systems have been studied in several applications like video surveillance, face-detection systems, and occupant posture analysis. In this paper, we present the development of a topology-based framework using a 3-D skeletal model for the robust detection and tracking of a vehicle occupant's head position from low-resolution range image data for a passive safety system. Unlike previous approaches to head detection, the proposed approach explores the topology information of a scene to detect the position of the head. Among the different available topology representations, the Reeb graph technique is chosen and is adapted to low-resolution 3-D range images. Invariance of the graph under rotations is achieved by using a Morse radial distance function. To cope with the particular challenges such as the noise and the large variations in the density of the data, a voxel neighborhood connectivity notion is proposed. A multiple-hypothesis tracker (MHT) with nearest-neighbor data association and Kalman filter prediction is applied on the endpoints of the Reeb graph to select and filter the correct head candidate out of Reeb graph endpoints. A systematic evaluation of the head detection framework is carried out on full-scale experimental 3-D range images and compared with the ground truth. It is shown that the Reeb graph topology algorithm developed herein allows the correct detection of the head of the occupant with only two head candidates as input to the MHT. Results of the experiments demonstrate that the proposed framework is robust under the large variations of the scene. The processing requirements of the proposed approach are discussed. It is shown that the number of operations is rather low and that real-time processing requirements can be met with the proposed method. [less ▲]

3D tomography of cells in micro-channels

in Applied Physics Letters (2017)

3D-Formanalyse von retroperitonealen Tumoren im Kindesalter: entwicklung einer statistischen 2D/3D-Methodik und Anwendung dieser mit MRT-Datensätzen

Scientific Conference (2010, September 18)

3‑Phosphoglycerate Transhydrogenation Instead of Dehydrogenation Alleviates the Redox State Dependency of Yeast de Novo L‑Serine Synthesis

in Biochemistry (2019)

The enzymatic mechanism of 3-phosphoglycerate to 3-phosphohydroxypyruvate oxidation, which forms the first step of the main conserved de novo serine synthesis pathway, has been revisited recently in ... [more ▼]

The enzymatic mechanism of 3-phosphoglycerate to 3-phosphohydroxypyruvate oxidation, which forms the first step of the main conserved de novo serine synthesis pathway, has been revisited recently in certain microorganisms. While this step is classically considered to be catalyzed by an NAD-dependent dehydrogenase (e.g., PHGDH in mammals), evidence has shown that in Pseudomonas, Escherichia coli, and Saccharomyces cerevisiae, the PHGDH homologues act as transhydrogenases. As such, they use α-ketoglutarate, rather than NAD+, as the final electron acceptor, thereby producing D-2-hydroxyglutarate in addition to 3-phosphohydroxypyruvate during 3-phosphoglycerate oxidation. Here, we provide a detailed biochemical and sequence−structure relationship characterization of the yeast PHGDH homologues, encoded by the paralogous SER3 and SER33 genes, in comparison to the human and other PHGDH enzymes. Using in vitro assays with purified recombinant enzymes as well as in vivo growth phenotyping and metabolome analyses of yeast strains engineered to depend on either Ser3, Ser33, or human PHGDH for serine synthesis, we confirmed that both yeast enzymes act as transhydrogenases, while the human enzyme is a dehydrogenase. In addition, we show that the yeast paralogs differ from the human enzyme in their sensitivity to inhibition by serine as well as hydrated NADH derivatives. Importantly, our in vivo data support the idea that a 3PGA transhydrogenase instead of dehydrogenase activity confers a growth advantage under conditions where the NAD+:NADH ratio is low. The results will help to elucidate why different species evolved different reaction mechanisms to carry out a widely conserved metabolic step in central carbon metabolism. [less ▲]

4-Amino-1,2,4-triazole: Playing a key role in the chemical deposition of Cu–In–Ga metal layers for photovoltaic applications.

in Thin Solid Films (2014)

4.2 Social Dynamics Metrics-Working Group Report

in Socio-Technical Security Metrics (2015)

Individuals continually interact with security mechanisms when performing tasks in everyday life. These tasks may serve personal goals or work goals, be individual or shared. These interactions can be ... [more ▼]

Individuals continually interact with security mechanisms when performing tasks in everyday life. These tasks may serve personal goals or work goals, be individual or shared. These interactions can be influenced by peers and superiors in the respective environments (workplace, home, public spaces), by personality traits of the users, as well as by contextual constraints such as available time, cognitive resources, and perceived available effort. All these influencing factors, we believe, should be considered in the design, implementation and maintenance of good socio-technical security mechanisms. Therefore, we need to observe reliable socio-technical data, and then transform them into meaningful and helpful metrics for user interactions and influencing factors. More precisely, there are three main questions that the group discussed: 1. What data do we need to observe and what of this data we actually can observe and measure? 2. How can we observe and measure? 3. What can we do with the results of the observations? [less ▲]

40 Jahre später : Kann die Einschätzung von Grundschullehrkräften zur Intelligenz ihrer Schülerinnen und Schüler deren Bildungsrenditen als Erwachsene vorhersagen?

Scientific Conference (2015)

40 Most Expensive Photographs. Blouin Art+Auction, Databank

Diverse speeches and writings (2017)

§§ 49 - 66 KAGB zur grenzüberschreitenden Tätigkeit und zum Europäischen Pass

in Kapitalanlagegesetzbuch, Kommentar (2019)

4D Biology for health and disease

in New Biotechnology (2011), 28(4), 291-293

The "4D Biology Workshop for Health and Disease", held on 16-17th of March 2010 in Brussels, aimed at finding the best organising principles for large-scale proteomics, interactomics and structural ... [more ▼]

The "4D Biology Workshop for Health and Disease", held on 16-17th of March 2010 in Brussels, aimed at finding the best organising principles for large-scale proteomics, interactomics and structural genomics/biology initiatives, and setting the vision for future high-throughput research and large-scale data gathering in biological and medical science. Major conclusions of the workshop include the following. (i) Development of new technologies and approaches to data analysis is crucial. Biophysical methods should be developed that span a broad range of time/spatial resolution and characterise structures and kinetics of interactions. Mathematics, physics, computational and engineering tools need to be used more in biology and new tools need to be developed. (ii) Database efforts need to focus on improved definitions of ontologies and standards so that system-scale data and associated metadata can be understood and shared efficiently. (iii) Research infrastructures should play a key role in fostering multidisciplinary research, maximising knowledge exchange between disciplines and facilitating access to diverse technologies. (iv) Understanding disease on a molecular level is crucial. System approaches may represent a new paradigm in the search for biomarkers and new targets in human disease. (v) Appropriate education and training should be provided to help efficient exchange of knowledge between theoreticians, experimental biologists and clinicians. These conclusions provide a strong basis for creating major possibilities in advancing research and clinical applications towards personalised medicine. [less ▲]