ISPRS, Vol.34, Part 2W2, “Dynamic and Multi-Dimensional GIS”, Bangkok, May 23-25, 2001
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3 Procedure
In this paper, laser-scanning system on the ground is a thing
that shall be used. In order to map all details of objects,
fundamental surveying is brought to data-collected process in
terms of data acquisition. After that all data is stored into the
proper format, those shall be filtered in order to reduce an error
occurring during collecting processes (Baltsavias, 1999).
Scene Modeling is a next step to create 3D model, after pass
filtering. Triangulation, segmentation, extraction are involved
also into Scene Modeling process in terms of mathematics
algorithms (Ackermann, 1999). And then all data should be
combined as one based on combination modeling to be
established for this purpose. The combination process,
consisting of algorithms to be used for merging different kinds
of data, is conducted to this process. GIS attribute data, aerial
photograph, existing map and laser data are the primary data
to be combined. The results of work can be shown on 3D
modeling as visualization, and also let the user to walk through
the visual spatial data (Hala, etc., 1999). Applications for this
modeling can be applied in several kind of work.
Our goal towards to reconstruct large-scale 3D spatial objects
byusing the laser range images (airborne or on the ground) and
existing maps or image. The Principe is shown in Figure 1 and
Figure 2. Laser range images can be thinking as a kind of high-
resolution digital terrain models (DTMs) or digital surface
models (DSMs). The reconstruction of 3D objects from laser
range images can be simply thought as the 3D raster-vector
conversions from a noisy DTM to parametric CAD formatted 3D
vector data. Due to the limited resolutions and noisy, the
existed low lever processing methods for reconstruction of 3D
objects from laser range images generally can not fit to real
application needs. Urban planning maps sever as set of well-
organized high lever data source interpreted and generalized
by human operators would be a kind of useful knowledge for
3D object reconstruction and recognition. Therefore, we set the
algorithm of 3D reconstruction into below major steps for our
approach(see the Figure3)
• Pre-Processing
• Laser range image filtering and segmentation;
• Extraction of 3D spatial objects
• Reconstruction of 3D objects as a 3D GIS needed
format.
• Visual Texture mapping
• Generation of VR environments
Figure3 The basic procedure of this research
