Reiner Creutzburg

Fast algorithm for computing the fractal dimension of binary images

Methods for determining fractal dimensions of image objects have gained increasing importance in recent developments of image processing. Mainly for the classification of shape and textures of natural objects the fractal dimension has proven its usefulness.

Volumetric Terrain Rendering with WebGL

Since the introduction of WebGL in 2011, the web browser evolved into a new and promising platform for high-performance 3D games. One of the most common game elements is heightmapbased terrain, but due to the limited expressiveness of this approach, the need for more sophisticated solutions becomes apparent. Many techniques exist that can convert an implicit surface into an approximated polygonal mesh. However, the actual application of such algorithms in a real-time environment, especially on mobile devices, where render time is of utmost importance has not been investigated sufficiently in the literature yet. The present work outlines the implementation of a multithreaded volumetric terrain engine using the 3D rendering framework Three.js and sheds light on the application of contouring methods in a realtime environment where the volume frequently changes through user interaction. The final system uses the Dual Contouring surface extraction technique and maintains discrete volume data in adjacent cells which can be modified on the fly using Constructive Solid Geometry. Furthermore, the performance of the engine is evaluated to determine its suitability for mobile devices.

Comparative visualization of the geometry of a hollow box girder using 3D-LiDAR – Part 2: Reconstruction of 3D Geometric Model

With the mandatory introduction of the May 2011 directive for reassessment of bridges in Germany, the administrations of the federal and state governments have the duty to prove the stability of their bridge stock. Verification of bridge stability will be realized with consideration of the newly increased traffic loads. Particularly in older bridges, the verification can only be achieved if calculative surplus load capacity of the original structural design is taken into account in the recalculation. One option for considering these reserves is the exact determination of the dead weight of the bridge. Within this case study, it will be demonstrated how the problem can be practically solved. nIn order to determine the dead weight of a concrete bridge, its volume has to be calculated. as a first step, a 3D laser scanner is used to record the internal geometry of a hollow box bridge girder. For the determination of the thickness of the concrete member, the non-destructive technique ultrasonic echo is applied. The construction must be segmented in approximately equidistant parts in order to be able to carry out an economic and efficient investigation. The description of the segmentation of the point cloud, carried out in a 2D model, was presented in the first part of the publication. The subject of this presentation is the merging of 2D cross sections into a 3D model, from which the weight of the bridge can be calculated.

Front Matter: Volume 6821

This PDF file contains the front matter associated with SPIE Proceedings Volume 6821, including the Title Page, Copyright information, Table of Contents, and the Conference Committee listing.© (2008) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.