The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part B5. Beijing 2008 
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Within this context it is highly recommended, to use the 
mathematical model according to Egels and Massou d'Autume 
of the IGN (Paris) for the generation of stereo mates. This 
quasi universal model so far has successfully been applied for 
digital image rectification purposes. It is suited to calculate 
Digital Terrain Model data and, depending on the situation, it 
allows partly to neglect equalization approaches. For tasks 
which require map accuracy, like photomaps (of facades), 
mosaikings, multisensor imagery and data fusion, a digital 
Geometric pixel by pixel image restitution is needed, 
preferably applying the indirect rectification method. 
In particular the converting of this kind of filtered image raster 
data into vector data, as for instance carried out by the ENVI 
Program system, promises great progress for automated ortho 
map production, also including the stereo mate. 
Open research topics for Technique Aspects of stereo 
views are, e.g., optimizing the generation of stereo views as 
well as searching for the geometric and radiometric potential 
of (available) stereo imagery; including the optimum 
digitization rate for analog stereo views, see. Figure 5, which 
shows a 1 st result for an optimum digitization rate for existing 
analog stereo views. In cas of fig 5 an analog stereopair of 
conventional aerial photographs in the scale 1:35 000 has been 
used for interpretation purposes. A first result is, due to the 
stereo effect the mapping potential of this original 3D-image 
is high, Approximately the same holds for the digitized 30- 
image showing 1.75m groundpixelsize, which, corresponds to 
a minimum digitization rate of 500 dots/inch. From Figure 5. 
can be seen, a relaxed groundpixelsize, ranging from, e.g., 
3.5m until 28 m, shows a decreasing in the mapping potential 
of the 3D image. To judge on the geometric potential of 
available stereo mates, relative spatial object distances of 
different object points Pi and PI are obtained from 
corresponding horizontal parallax values Apxi and Apxfalso 
known as disparities, according to yi/yl= pxi/pxl. Additional 
open research topics for Technique aspects are derived from 
the combination of stereo mates of different physical character. 
To be mentioned is a systematic considering of the effect of 
the stereoscopic exaggeration caused by an extremely high 
base-to-distance ratio near 1 Other open research topics for 
Technique aspects are considering the effect of the 
stereoscopic exaggeration caused by a combination of 
stereomates showing different focus as well as the role of the 
dominant eye. 
Mapping potential of rasterimagery and photos 
(for medium scolc topographic mapping of rural areas) 
stereo 
higfi 
Mapping 
Potential 
good 
medium 
low 
(tostsile Vili ufranohe-sur-Cher 
(France)) 
original U3SOOO 
interpiani • * -- ~ ve get- 
topographic objects 
_. 3.i> m 
ff 14 m 
buildii*d»' twat * s ^ r ^ m 
groundpixelsize 
Figure 5. Results of advantages from spatial (“stereo”) image data interpretation as carried out by A. Elmhorst 
Figure 6. i-Grammetry: paths of homologues points from observing a stereo view (left) and in an enlarged part (right) according 
to G.Guienko &V.Chekalin