EXPERIMENTS IN DIGITAL PROCESSING OF PHOTOGRAMMETRIC IMAGES 
B. Kunji 
ITC (Int.Institute for Aerial Survey and Earth Sciences). 
The Netherlands 
Commission II. 
Abstract: Recently in ITC a series of experiments was performed on 
digital image display and processing techniques. This paper des- 
cribes the existing hardware configuration, the image segmentation 
for display and the image matching. Moreover initial experiments 
were carried out on  relative- and absolute orientation and 
superimposed stereo plotting. 
INTRODUCTION 
The first experiments in automatic processing of photogrammetric 
images (image matching techniques, DTM, etc). took place more than 
twenty five years ago, when Hobrough applied the electronic image 
processing techniques. A few years later S. Bertram described the 
first hybrid system and J.V. Sharp (at al) the fully digital map 
compilation. After the introduction of micro electronics and the 
recent development of very-large-scale integration, systems are now 
becoming economically feasable for all-digital photogrammetric image 
processing. As the development has been gradual and fragmentary, it 
is difficult to give the proper credit to individual contributors 
for their contribution to digital photogrammetric image processing. 
The aim of the initial development of a low cost photogrammetric 
work station using standard computer peripherials, and the experim- 
ents conducted up till now at the ITC was, to identify the operat- 
ional process characteristics of such a system. The automatic image 
matching requires some process parameters to be specified before or 
tuned during operation. The image matching operation should anyhow 
be interactive, for verification and intervention in critical sit- 
uations, by the operator. Finally interactive editing of raw DTM 
data is required. To this end a color display terminal can be used, 
which can provide a stereo view for both the photo-pair image and 
the obtained DTM data. Such a station is also applicable to the 
measurement of photo-coordinates for relative and absolute orientat- 
ion and by using a XY-tablet, the same station can be used for 
Stereo plotting. 
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