We study the problem of placing guard towers on a terrain such that the terrain can be seen from at least one tower. This problem is important in many applications, and has an extensive history in the literature (known as, e.g., multiple observer siting). In this paper, we consider the problem on polyhedral terrains, and we allow the guards to see only a fixed fraction of the terrain, rather th...

Real-time terrain rendering techniques usually employ static data structures and do not allow interactive modification of the terrain. In this paper we describe a real-time geometric clipmapping terrain rendering technique for large terrains which allows incremental updates of the underlying data structure. We have combined the method with an interactive sketch-based terrain modelling technique...

This paper presents a technique for incorporating terrain traversability data into a global path planning method for field mobile robots operating on rough natural terrain. The focus of this approach is on assessing the traversability characteristics of the global terrain using a multi-valued map representation of traversal dificulty, and using this information to compute a traversal cost funct...

Visual sensing techniques are presented for enhancing rover traversability assessment on planetary surfaces. Geometric information from stereo image range data is used to identify salient terrain features such as rocks, and that information, along with terrain image appearances, is associated with rover traversability. Performance of rule-based, neural network, and fuzzy logic methods for class...

In order to maneuver autonomously on rough terrain, a mobile robot must constantly decide whether to traverse or circumnavigate terrain features ahead. This ability is called Obstacle Negotiation (ON). A critical aspect of ON is the socalled traversability analysis, which evaluates the level of difficulty associated with the traversal of the terrain. This paper presents a new method for travers...

Real-time strategy (RTS) games represent a mainstream genre of video games. They are also practical test-beds for intelligent agents, which have received considerable interest from Artificial Intelligence (AI) researchers, in particular game AI researchers. Terrain knowledge understanding is a fundamental issue for RTS agents and map decomposition methods can help AI agents in representing terr...

The Joint Training Data Services (JTDS) is a web-based set of services that provide Modeling and Simulation (M&S) ready data and scenario development tools to the DoD Enterprise to support Joint and Service theater level constructive & virtual training. JTDS provides persistent web access to an Order of Battle Service and a Terrain Generation Service (TGS) that leverage unique data repositories...

A path from s to t on a polyhedral terrain is descending if the height of a point p never increases while we move p along the path from s to t. No efficient algorithm is known to find a shortest descending path (SDP) from s to t in a polyhedral terrain. We give two approximation algorithms (more precisely, FPTASs) that solve the SDP problem on general terrains. Both algorithms are simple, robus...

This paper presents a new method of automatic lineament extraction which includes the removal of the ‘artefacts effect’ which is associated with the process of raster based analysis. The core of the proposed Multi-Hillshade Hierarchic Clustering (MHHC) method incorporates a set of variously illuminated and rotated hillshades in combination with hierarchic clustering of derived ‘protolineaments’...

A physically-based model to correct atmospheric and topographically induced illumination effects in optical satellite data is developed and tested. Special emphasis is put on the impact of rugged terrain. Ground reference data for various land use classes enables the assessment of the corrections' influence on land use classifications. The estimation of surface reflectance is achieved in a two-...