Computational wave propagation models are widely used in underwater and atmospheric sound propagation simulation. In most realistic cases the physical domains involved are irregular. We have developed finite element techniques, applied to general irregular meshes and coupled with discrete, artificial absorbing boundary conditions of nonlocal type, for the Helmholtz equation and its ‘standard’ p...

This paper addresses the problem of large scale terrain modeling for a mobile robot. Building a model of large scale terrain that can adequately handle uncertainty and incompleteness in a statistically sound way is a challenging problem. A recent work [Vasudevan et al., 2009] proposed non-stationary Gaussian processes (GP’s) based on the neural network kernel as a solution to the problem. GP’s ...

Traditionally, terrain simplification is time consuming and generates multi-resolution models, from which irregular or semi-regular triangulations are extracted to render a terrain at a suitable level of detail. Recent terrain simplification techniques use GPU-friendly regular grids and apply the filtering and sub-sampling paradigm to generate multiple resolutions. However, such approximations ...

In this paper a methodology for the combination and integration into a single data base of terrain and building data is presented. This study is justified if ray-tracing techniques are to be used in propagation and channel modeling studies. Usually terrain is available in grid or elevation form while building information is normally facet-oriented. Ray-tracing (RT) techniques deal with flat fac...

An intelligent walking strategy is vital for multi-legged robots possessing no a priori information of an environ‐ ment when traversing across discontinuous terrain. Sixlegged robots outperform other multi-legged robots in static and dynamic stability. However, hexapods require careful planning to traverse across discontinuous terrain. A hexapod walking strategy can be accomplished using a visi...

This paper describes the implementation of three methods for fitting surfaces: linear, quintic and stochastic. It uses qualitative (visual) and quantitative (statistical) criteria to compare the three approaches. The digital terrain model is based on a triangular irregular network (TIN) structure and the comparison is performed using a mathematically defined function and real data obtained from...

Generic lossy image compression algorithms, such as Said & Pearlman's, perform excellently on gridded terrain elevation data. For example, an average DEM compressed down to 0.1 bits per point has an RMS elevation error of 3 meters, although di erent DEMs ranged from 0.25 to 15 meters. This performance compares favorably to compressing with Triangulated Irregular Networks. Preliminary tests also...

Digital Terrain Modeling, the Triangulated Irregular Network (TIN) is a representation of a surface derived from irregularly spaced sample points and break line features. Paper deals with the basic concept of Delauney’s triangulation method with its practical approach in ArcGIS. The next section describes the process to convert mass points to TIN model and explores some of the basics of TIN Mod...