Werner Benger - Academia.edu (original) (raw)

Papers by Werner Benger

Advances in Applied Clifford Algebras, Nov 23, 2021

Typically, airborne laserscanning includes a laser mounted on an airplane or drone (its pulsed be... more Typically, airborne laserscanning includes a laser mounted on an airplane or drone (its pulsed beam direction can scan in flight direction and perpendicular to it) an intertial positioning system of gyroscopes, and a global navigation satellite system. The data, relative orientation and relative distance of these three systems are combined in computing strips of ground surface point locations in an earth fixed coordinate system. Finally, all laserscanning strips are combined via iterative closes point methods to an interactive three-dimensional terrain map. In this work we describe the mathematical framework for how to use the iterative closest point method for the adjustment of the airborne laserscanning data strips in the framework of conformal geometric algebra.

Computer Science Research Notes, Jul 1, 2023

Journal of WSCG, 2020

Airborne light detection and ranging (LIDAR)-based bathymetry is a highly specialized field withi... more Airborne light detection and ranging (LIDAR)-based bathymetry is a highly specialized field within the widely known and used geoscientific surveying technology based on green spectrum lasers. Green light can penetrate shallow water bodies such that river and lake beds can be surveyed. The result of such observations are point clouds, from which geometries are extracted, such as digital elevation maps for lake, river or sea floors. The quality of those maps is crucially dependent on the amount of reliable information that can be extracted from the noisy LIDAR signals. The primary LIDAR data consists of amplitude response curves for each emitted laser signal. A direct visualization of these "raw", pristine data is crucial to verify, assess and optimize subsequent data processing and reduction methods. In this article we present a method for scientific visualization of these amplitude response curves en mass, i.e. for millions and tens of millions thereof simultaneously. As part of this direct visualization also preliminary analysis and data reduction operations can be performed interactively. This primary and direct inspection allows studying and evaluating the full potential of acquired data sets such that data processing methods can be fine-tuned to squeeze out all needed information of interest. Ideally such improved data processing avoids subsequent surveying when output from already measured data sets is improved, resulting in reduced economical and environmental costs.

2014 AGU Fall Meeting, Sep 29, 2014

EGU General Assembly Conference Abstracts, Apr 1, 2018

The High-End-Visualization Workshop is a tentatively annual meeting of active researchers in the ... more The High-End-Visualization Workshop is a tentatively annual meeting of active researchers in the fi eld of scientific visualization with application domain scientists, in particular from high-performance computing. Historically it originated from a creative workshop involving members of the Numerical Relativity Group at the Max-Planck-Institute for Gravitational Physics in Potsdam, Germany, and researchers of the Department for Scientific Visualization at the Zuse-Institute Berlin, Germany, as well as astrophysicists from the Institute for Astrophysics at the University of Innsbruck, Austria. Since its original birth in 2004 the workshop has grown its own momentum.

Geometric Algebra is considered as a very intuitive tool to deal with geometric problems and it a... more Geometric Algebra is considered as a very intuitive tool to deal with geometric problems and it appears to be increasingly e cient and useful to deal with computer graphics solutions. For example, the Conformal Geometric Algebra includes circles, spheres, planes and lines as algebraic objects, and intersections between these objects are also algebraic objects. More complex objects such as conics, quadric surfaces can also be expressed and be manipulated using an extension of the conformal Geometric Algebra. However due to high dimension of their representations in Geometric Algebra, implementations of Geometric Algebra that are currently available do not allow e cient realizations of these objects. is paper presents a Geometric Algebra implementation dedicated for both low and high dimensions. e proposed method is a hybrid solution for precomputed code with fast execution and runtime computations with low memory requirement. More speci cally, the proposed method combines a precomputed table approach with a recursive method using binary trees. Some rules are de ned to select the most appropriate choice, according to the dimension of the algebra and the type of multivectors involved in the product. e resulting implementation is well suited for high dimensional spaces (e.g. algebra of dimension 15) as well as for lower dimensional space. is paper details the integration of this hybrid method as a plug-in into Gaalop, which is a very advanced optimizing code generator. is paper also presents some benchmarks to show the performances of our method, especially in high dimensional spaces.

Proceedings of Computer Graphics International 2018, 2018

Leaflets are a common technology used in web services to provide high resolution maps by providin... more Leaflets are a common technology used in web services to provide high resolution maps by providing them in tiles of incremental resolutions. While for 2D display an unique level of resolution is all that is needed, within a 3D perspective display a combination of resolution levels needs to be identified. Block-Structured Adaptive Mesh Refinement (AMR) utilizes an organisation of data similar to Leaflets, but deals with 3D or 4D volumetric blocks of data. Such a data organisation is very suitable for hierarchical organisation of big data. In this article we propose using the AMR data organisation for hierarchical structuring of arbitrary geometric primitives, i.e. point clouds, sets of lines, triangle meshes, volumes. Such data organisation allows for generic and performant data access of out-of-core data on demand, as relevant for navigation through big data. Ultimately identification of data block visibility is crucial for a fluid interactive experience. We propose an algorithm based on Conformal 5D Geometric Algebra to approximate bounding boxes via spheres and the view frustum as a cone to arrive on a visibility criteria used for priority sorting of candidate blocks.

Advances in Applied Clifford Algebras, Apr 10, 2017

Geometric algebra (GA) is a promising approach to address interoperability bottlenecks that are p... more Geometric algebra (GA) is a promising approach to address interoperability bottlenecks that are particularly prominent in the big data era. Similar to how GA unites and simplifies otherwise distinct mathematical branches it may also help to unite software via common interfaces between otherwise distinct applications. The promising potential of GA would be best exhibited by the ability of seamless integration into existing, complex applications. To achieve this vision various constraints have to be considered. Particularly having C++ in focus, we discuss the "wish list" that an optimal C++ implementation should provide. We find that to cover the various constraints an hybrid approach benefiting from multiple programming paradigms, ranging from generic to object-oriented programming, will be needed. C++ is a very suitable platform providing all these capabilities and promising approaches like Generative Programming and Active Libraries provide technology highly desirable for universally promoting GA to an extensive range of application domains. Mathematics Subject Classification. Computing methodologies and applications 68U01, Computer science applications 97R99, Applications of universal algebra in computer science 08A70.

Hurricane Katrina has had a devastating impact on the US Gulf Coast. Forecasts of such events, co... more Hurricane Katrina has had a devastating impact on the US Gulf Coast. Forecasts of such events, coupled with timely response, can greatly reduce casualties and save billions of dollars. In our effort, we use sophisticated surface, flow and volume visualization techniques show the storm surge and atmospheric simulations simulation results superimposed with actual observations, including satellite cloud images, GIS aerial maps and elevation maps showing the 3D terrain of New Orleans. We have developed efficient data layout mechanisms to ensure fast and uniform access to the multiple time-varying datasets. In particular for rendering, we focus on continuous and discrete level of detail algorithms used to render large terrains of the Mississippi basin and also remote visualization techniques to stream the rendered results across the network to large display clients. Our primary contribution is in adapting existing state of the art research in data access, rendering and display mechanisms and devising an overall framework for application in hurricane and coastal modeling.

Communications of The ACM, Oct 1, 2009

The biosciences need an image format capable of high performance and long-term maintenance. Is HD... more The biosciences need an image format capable of high performance and long-term maintenance. Is HDF5 the answer? bY mAttheW t. DouGhertY, miChAeL J. foLK, ereZ ZADoK, herbert J. bernstein, frAnCes C. bernstein, KeVin W. eLiCeiri, Werner benGer, ChristoPh best Related articles on queue.acm.org Catching disk latency in the act http://queue.acm.org/detail.cfm?id=1483106

Journal of Biomechanics, 2006

Springer eBooks, 2011

Images in scientific visualization are the end-product of data processing. Starting from higher-d... more Images in scientific visualization are the end-product of data processing. Starting from higher-dimensional datasets, such as scalar-, vector-, tensor-fields given on D, D, D domains, the objective is to reduce this complexity to two-dimensional images comprehensible to the human visual system. Various mathematical fields such as in particular differential geometry, topology (theory of discretized manifolds), differential topology, linear algebra, Geometric Algebra, vectorfield and tensor analysis, and partial differential equations contribute to the data filtering and transformation algorithms used in scientific visualization. The application of differential methods is core to all these fields. The following chapter will provide examples from current research on the application of these mathematical domains to scientific visualization and ultimately generating of images for analysis of multi-dimensional datasets.

A new visualization technique for visualizing three-dimensional symmetric positive definite tenso... more A new visualization technique for visualizing three-dimensional symmetric positive definite tensor fields of rank two is described. It supports studying the spatial projection of a spacetime metric. The rendering technique is demonstrated upon the Schwarzschild metric of a static black hole, the Kerr metric of a rotating black hole in two different coordinate systems, and a numerically computed dataset describing the metric of two colliding black holes.

Springer eBooks, 2000

Konrad-Zuse-Zentrum für Informationstechnik Berlin WERNER BENGER(AEI 1 , ZIB 2), HANS-CHRISTIAN H... more Konrad-Zuse-Zentrum für Informationstechnik Berlin WERNER BENGER(AEI 1 , ZIB 2), HANS-CHRISTIAN HEGE (ZIB), ANDRÉ MERZKY (ZIB), THOMAS RADKE (AEI), EDWARD SEIDEL (AEI)