triangulates the relative position of the selected feature and 
transfer it into the global coordinate system. 
In addition to calculating locations, the software will 
provide for the selection, control and display of the video 
images. A map window display the tracking of the 
GPSVision, the image location and the extracted features. 
An image pair is selected from the map window or using 
forward/backward image function. The image can be 
viewed in the zoom mode and its contrast is easily 
adjustable. The user selects the active feature and assigns 
attributes to it. After measuring the left and right image 
coordinate, the global coordinate or the distance 
measurement is also displayed. 
By using the image matching method, the features are 
positioned by selecting a point on one of the stereo 
images. It reduce the feature extraction time by half. 
Another application of the image matching technology is 
to measure the profile and surface of object. 
The stereo vision system of the GPSVision collects 
huge amount digital data. Automated feature extraction 
is very important to the mobile mapping system, but it is 
still in the research step. One test has been done with 
automatic extraction of the road edge lines, it works 
with the well-painted road edges, but it still can’t be 
used in the production. The automated relative 
orientation and triangulation could be implemented for 
the mobile mapping system, but they are not so critical, 
because these procedures do not require to much effort 
to be performed by a person. How to more efficiently 
extract the information from stereo images will be the 
next focus of our new development. 
After the feature extraction, a standard output file is 
created which contains all feature information about the 
collected features. The Re-Formatting software processes 
the standardized output files of the Feature Extraction 
Software and create the required input files for the 
targeted AM/FM or GIS system. Like the Feature 
Extraction Software the Re-Formatting Software packages 
will use the same external rule files to control the 
processes. 
The GPSVision is a data acquisition tool to create the 
land-based digital information. In the couple months 
after the GPS Vision is in operation, several applications 
have been accomplished. The street center lines created 
by the GPSVision are used to rectify 
aerophotographies for Gas company in Wisconsin. 
Infrastructure elements, like, manholes, fire hydrants, 
collected by the GPSVision are used for management 
and planning by the city of Hopkins, Minnesota. A 
company in Thailand, Real Time, Ltd. uses the 
GPSVision to map the city of Bangkok. Experiences 
show that the data acquisition procedure by the 
GPSVision is fast, accurate and lower cost than 
traditional methods. 
  
  
Iroaye Paxds 2074 | ELECT TEE 
  
  
  
Fig. 4 Georeferenced stereo image pair taken from Bangkok, Thailand. 
Two poles and one manhole are extracted from this image pair. 
158 
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