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Significance of Photogrammetry in 3D Visualization and Building Reconstruction
Conclusion
This application delivers 3D perspective walk or drive-through. Many movie-like simulations of travel through a 3D virtual world are pre-computed with the path being fixed. In this application there are a very large number of from - to solutions. Location is solved through use of the internet and 2D GIS maps to define source (GPS in a vehicle is an alternative here) and destination. Route optimization occurs once observer parameters are defined. High performance computer(s) provide a solution for the walk or drive along the optimized route and this is delivered to the observer.
Results indicate that a) architecturally simplistic buildings, which present flat facets to an observer, are much easier to measure and render than architecturally complex buildings; b) whilst it is important to render in some detail visual landmarks, significant effort can be saved by using simple tone or typical textural rendering of less significant features; c) it is practically difficult to accurately render all sides of 3D objects; d) greater realism is achieved when familiar objects such as trees and vehicles are added to the 3D model; and e) maintenance of geographic coordinates is difficult in existing geo-visualization software if quality visual enhancement of 3D objects is desired.
VRML browsers are generally known as means of visualization of 3D graphics on the Web (cosmo player), allowing real-time navigation. In this research project, reconstructed buildings and related features are coded in VRML file (see Figure 5) that opens in normal Internet browser. If the user wants to click on a building, a sensor has to be attached to this building in the VRML document. If the user wants to have the animation of a walk along a street, the route and the speed of walking have to be specified in a special VRML node. Linking 3D VRML environments to a relational database is a challenge. The project also demonstrated that interactive geo-query tools are used for querying 3-D visualizations, enabled by seamless links to GIS-based attributes, providing a framework for a suite of 3-D landscape design capabilities.
Further Research
An IBM ViaVoice embedded system was tested to monitor its interaction with windows platform and it was noted further improvements are needed. Windows Developer Kit can be used to write algorithms so that the application (1) will integrate with GPS system, (2) the system is integrated with a database in order to map real time coordinates and (3) the user can interact with touch screen or voice command recognition. Software share several key capabilities that go beyond the requirements for vastly improved performance. Such capabilities include: (1) 3-D object rendering of symbols such as trees, buildings and other manmade features. (2) Texture mapping to support realistic rendering of polygonal features such as roads, meadows, open water and background sky and (3) Wireframe upgrading from triangle snapping geometry to user defined octagons, rectangles etc.
In this project application, car wireframes and trees (see figure 5) are shaped and added to affix more realism to the environment. The research project demonstrated that 3D Geo-Visualization of urban environment is not a simple process, but is in fact a whole new dimension of research and visualization. It is argued that these psycho-perceptual issues require careful consideration as they can significantly influence the cost and effort of generating data.
References
- [Ghardian & Bishop] Payam Ghardirian and Ian D. Bishop, AURISA 2002. “Composition of Augmented Reality and GIS to Visualize Environmental Change”.
- [Fischer et al, 1999] Fischer A., Kolbe T.H., and Lang F. (1999). On the Use of Geometric and Semantic Models for Component-Based Building Reconstruction Proceeding. Semantic Modelling for the Acquisition of Topographic Information from Images and Maps, Smati ’99 Workshop, Institute of Photogrammetry, Bonn University, pages: 101-119.
- [Forstner 1999] Forntner W. (1999). 3D City Models. Automatic and Semiautomatic Acquisition Methods. Photogrammetric Week, Stuttgart.
- [Brunn et al, 1996] Brunn, A., E. Gülch, F. Lang and W. Förstner: A Multi-Layer Strategy for 3D Building Acquisition, in: Proceedings of the IAPR TC-7 Workshop, Graz, Austria, September 2-3, pp. 11-37, 1996
- [GrünA 1996] Grün, A.: Generierung und Visualisierungvon 3-D Stadtmodellen, in: Proceedings of the IAPR TC-7 Workshop, Graz, Austria, September 2-3, pp. 183-196, 1996
- [Hendr 1997] Hendrickx M., J. Vandekerckhove, D. Frere, T. Moons and L. V. Gool: 3D Reconstruction of House Roofs from Multiple Aerial Images of Urban Areas, in: IAPRS, Vol. 32 Part 3-4W2, Stuttgart, September 17-19, pp. 88-95, 1997
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