Denis Fisseler

Analysis of the Accuracy and Robustness of the Leap Motion Controller

The Leap Motion Controller is a new device for hand gesture controlled user interfaces with declared sub-millimeter accuracy. However, up to this point its capabilities in real environments have not been analyzed. Therefore, this paper presents a first study of a Leap Motion Controller. The main focus of attention is on the evaluation of the accuracy and repeatability. For an appropriate evaluation, a novel experimental setup was developed making use of an industrial robot with a reference pen allowing a position accuracy of 0.2 mm. Thereby, a deviation between a desired 3D position and the average measured positions below 0.2 mm has been obtained for static setups and of 1.2 mm for dynamic setups. Using the conclusion of this analysis can improve the development of applications for the Leap Motion controller in the field of Human-Computer Interaction.

Learning in a High Dimensional Space: Fast Omnidirectional Quadrupedal Locomotion

This paper presents an efficient way to learn fast omnidirectional quadrupedal walking gaits. We show that the common approaches to control the legs can be further improved by allowing more degrees of freedom in the trajectory generation for the legs. To achieve good omnidirectional movements, we suggest to use different parameters for different walk requests and interpolate between them. The approach has been implemented for the Sony Aibo and used by the GermanTeam in the Four-Legged-League in 2005. A standard learning strategy has been adopted, so that the optimization process of a parameter set can be done within one hour, without human intervention. The resulting walk achieved remarkable speeds, both in pure forward walking and in omnidirectional movements.

Simulation of Intra-Aneurysmal Blood Flow by Different Numerical Methods

The occlusional performance of sole endoluminal stenting of intracranial aneurysms is controversially discussed in the literature. Simulation of blood flow has been studied to shed light on possible causal attributions. The outcome, however, largely depends on the numerical method and various free parameters. The present study is therefore conducted to find ways to define parameters and efficiently explore the huge parameter space with finite element methods (FEMs) and lattice Boltzmann methods (LBMs). The goal is to identify both the impact of different parameters on the results of computational fluid dynamics (CFD) and their advantages and disadvantages. CFD is applied to assess flow and aneurysmal vorticity in 2D and 3D models. To assess and compare initial simulation results, simplified 2D and 3D models based on key features of real geometries and medical expert knowledge were used. A result obtained from this analysis indicates that a combined use of the different numerical methods, LBM for fast exploration and FEM for a more in-depth look, may result in a better understanding of blood flow and may also lead to more accurate information about factors that influence conditions for stenting of intracranial aneurysms.

Extending philological research with methods of 3D computer graphics applied to analysis of cultural heritage

Philological research on ancient cuneiform texts with the goal of analyzing and reconstructing manuscripts from a large quantity of available unsorted tablet fragments is a time consuming task. As the number of tablet fragments and the number of signs on the fragments both exceed values which can be handled by means of conventional manual research methods in a reasonable amount of time, the use of computer aided research methods is an obvious choice. In this paper, we present a novel unified approach for integrating methods of computer graphics into the process of analyzing and joining cuneiform tablet fragments. We will cover a selection of essential research scenarios and identify aspects where those methods can be applied to enhance and extend traditional philological research processes or even help to access formerly unavailable layers of information. This is achieved by integrating methods for visualization, interactive 3D script feature extraction, script analysis, virtual fragment joining and intuitive measurement and annotation tools in our fast and easy to use software framework CuneiformAnalyser, designed for large data sets. Unlike other approaches, our solution integrates for the first time methods to support every aspect of the manuscript analysis and reconstruction process in a single system.

Retrieving Cuneiform Structures in a Segmentation-free Word Spotting Framework

Cuneiform tablets are an invaluable documentation of early human history. Efforts are being made in digitizing large tablet collections for preserving their content and making them available to a global research community. However, there are hardly any automated computer aided methods for supporting philologists in their analysis. In this paper we present an approach for automatically retrieving cuneiform wedge constellations from digitized cuneiform tablet collections. Compelling results could be achieved in our qualitative and quantitative evaluation on a challenging benchmark consisting of 3D-scanned cuneiform tablets.

Web-Based Scientific Exploration and Analysis of 3D Scanned Cuneiform Datasets for Collaborative Research

The three-dimensional cuneiform script is one of the oldest known writing systems and a central object of research in Ancient Near Eastern Studies and Hittitology. An important step towards the understanding of the cuneiform script is the provision of opportunities and tools for joint analysis. This paper presents an approach that contributes to this challenge: a collaborative compatible web-based scientific exploration and analysis of 3D scanned cuneiform fragments. The WebGL -based concept incorporates methods for compressed web-based content delivery of large 3D datasets and high quality visualization. To maximize accessibility and to promote acceptance of 3D techniques in the field of Hittitology, the introduced concept is integrated into the Hethitologie-Portal Mainz, an established leading online research resource in the field of Hittitology, which until now exclusively included 2D content. The paper shows that increasing the availability of 3D scanned archaeological data through a web-based interface can provide significant scientific value while at the same time finding a trade-off between copyright induced restrictions and scientific usability.

Modellierung einer raumbezogenen Datenbank zur Repräsentation und Analyse syntaktischer und semantischer Merkmale von Keilschrifttafeln

ZusammenfassungDie vorliegende Arbeit zeigt eine neuartige Herangehensweise zur Analyse von Keilschrifttafeln sowie zur Rekonstruktion von dreidimensionalen Schriftträgern über eine raumbezogene relationale Datenbank auf. Dabei ist bereits die integrierte Datenhaltung von dreidimensionalen syntaktischen und semantischen Merkmalen für Keilschrifttafeln innovativ, absolutes Neuland wird mit der Datenbank-gestützten Ermittlung von 3D-Joins auf Basis von geometrischen Informationen sowie zeit- und ortsspezifischen paläographischen Kriterien betreten. In Kombination mit dieser zur Verfügung stehenden Veredelung bestehender Daten und einer nachhaltigen Erweiterung der Datenbasis, werden neue Möglichkeiten zur Gewinnung philologischer Erkenntnisse zur Verfügung stehen und vorhandene Ansätze effektiviert.