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International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B6. Istanbul 2004 
Project Management Tool 
Flight Management 
FotoCaptor OrtoCaptor | StereoCaptor 
Feature extraction Feature extraction Stereoscopic 
using previously 
oriented images 
Registration 
not available 
Coordinate On-line 
rectification 
Transformation 
using registered 
images or maps 
. OrtoMotor 
| feature extraction 
Registration 
available 
2D - 3D Vectorial File 
Figure 1. General schema of STEREOVISOR system 
2. PROJECT MANAGEMENT 
The Project Management tool is designed for the search, 
consultation and visualization of available photogrammetric 
information of a determined geographic zone. This is the data 
selection module that will be used in the feature extraction 
process. 
The database includes the information about aerial 
photographs (figure 2), orientation parameters, digital 
elevation models (figure 3) and orthoimages (figure 4). 
This module allows for alphanumerical and graphical data 
visualization and query. Also it is possible to view other 
auxiliary information, such as flight maps, in order to 
complete the project information. 
These different data types must be completed with the 
corresponding metadata in order to provide the simple and 
agile consultation and management of the available 
information. The metadata must also contain the orientation 
parameters and complementary photogrammetric information 
that will be necessary for a correct evaluation and analysis of 
available information. 
The Project Management tool allows for appropriated data 
selection for subsequent vector feature extraction. Depending 
on available data, the system will select among the three 
available feature extraction tools: StereoCaptor (from 
stereoscopic models), OrtoCaptor (from orthoimages) and 
FotoCaptor (from orientated images). It is possible to access 
the different feature extraction tools using the Flight 
Management tool or export the select data in order to use 
them directly from the feature extraction tools. 
3. VISUALIZATION AND FEATURE EXTRACTION 
The feature extraction tools include the graphic functions for 
vector and thematic information extraction obtained from 
149 
previously oriented images (from direct —GPS/INS- or 
indirect orientation methods), stereoscopic models or 
orthoimages (with or without DEM). 
The tools are designed to provide the necessary tools for 
thematic information extraction (land use, vegetation, forest 
maps) or urban and rural mapping from large scales (1/500 to 
1/2.000) to small scales (1/5.000). 
The system includes all the functions that are usually 
available in digital photogrammetric systems. 
All the functions are common for the different feature 
extraction tools, making it a user-friendly system that is easy 
to learn. Functions are also fully customizable according the 
particular characteristics of the work or user preferences. 
3.1 StereoCaptor 
The StereoCaptor tool allows for 3D feature extraction from 
stereoscopic models, using a similar schema as in 
conventional stereoplotters. 
The stereoscopic visualization is based on the use of anaglyph 
images and it is specially designed to obtain perfect vision 
when infrared images are used (figure 5). 
The vector information is superimposed to the stereoscopic 
imagery. 
To put the extraction cursor on the ground, you can: (a) move 
the cursor manually with the mouse; (b) use the Snap-To- 
Ground function (the computer will automatically put the 
cursor on the ground using correlation functions, provided 
you have positioned it approximately); or (c) provide a terrain 
data file and instruct the software to have the extraction 
cursor “track” the DTM.