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processing system to derive DEMs and 
orthophotos from digitized aerial or 
satellite (SPOT) images. 
Construction, Refinement and Rule- 
Based Segmentation of the Object Space 
The objective of this project is to 
automatically extract features in the 3-D 
object space. This requires the 
construction of the object space from 2-D 
projections and its constant refinement. 
The result will be a set of structural 
descriptions, each corresponding to an 
interesting entity in the scene. 
Campus Mapping 
A digital map of the campus of The Ohio 
State University is being generated by 
photogramme try students, which will be 
used by the campus facilities management 
to establish a CIS of the campus area. 
This is a perfect example where students 
perform practical work closely related to 
their studies and gain experience with 
photogrammetric instruments. 
EQUIPMENT 
The revolution in digital photogrammetry 
is very well documented in our laboratory 
equipment. We are proud to possess state- 
of-the-art analytical plotters which enable 
students to exercise all types of 
photogrammetric data analysis and mostly 
are used for labs and practical work. In 
addition, a number of imaging 
workstations from different manu 
facturers are available for research and 
software development in digital 
photogrammetry. An overview of most 
of the hardware currently used is shown 
in the figure. 
The host computer of the photo 
grammetry lab is a MicroVax. It connects 
to the campus network which enables us 
to access all computers of The Ohio State 
University and includes a Cray Y- 
MP8/864 of the Ohio Supercomputer 
Center. However, during the last years, 
more and more image computing has 
been done on workstations. Presently, a 
DECstation 3100, a SUN SPARC 
station-1, and an Intergraph Clipper 
workstation are available to photo 
grammetry students and researchers. We 
also acquired two X-Terminals and can 
use the department’s Silicon Graphics 
Workstation. There are a number of 
PC-AT 386 compatibles and MAC’IIs— 
some are equipped with image processing 
and frame capture boards which allow for 
real-time photogrammetric image process 
ing. They can also be connected to our 
analytical plotters and the campus 
network. Additionally, we have full 
access to special equipment needed for 
research projects which is located at the 
Center for Mapping. 
We own a variety of cameras for both 
analog photography, as well as a digital 
image acquisition. There is a Zeiss RMK 
aerial camera with a reseau, which 
recently was used for tests by the Ohio 
Department of Transportation, a Wild 
P32 metric-close range camera as well as 
a Hasselblad semi-metric camera. The last 
two are used for student labs. To scan 
photographs with a resolution of 4096 x 
4096 pixels, we use an EIKONIX 
line-scan camera which is interfaced to 
the MicroVax. For real-time photogram 
metry, two Plitachi frame type CCD 
cameras are directly connected to a 
MATROX MVP-AT frame grabber and 
image processor. 
Photogrammetric mapping projects as 
well as student labs are done on our three 
analytical plotters: the Kern DSR-1, 
equipped with 2 CCD cameras for 
automatic coordinate measurement and 
interfaced to a PC-AT running AutoCAD; 
the Wild BC-1, the “workhorse” of the 
photogrammetry lab which is especially 
used for online plotting (on the TA2 
plotting table) and for DEM data capture; 
and the Zeiss P-1, which allows 
capturing data directly in the Phocus - 
GIS and displaying the results overlaid 
over the stereo-model with a 
“Videomap”. 
SUMMARY 
The photogrammetry program at the 
Department of Geodetic Science and 
Surveying of The Ohio State University