Full text: XVIIIth Congress (Part B3)

Image chips were used in an early study for automatic 
satellite image rectification using ground control points 
(Malmström 1986). The chips and their object space 
coordinates were generated using scanned aerial photo- 
graphy, and were subsequently stored in a database. Area 
based matching was used to locate the chips in Landsat 
MSS imagery. To the knowledge of the author no follow 
up studies have been published. Possibly this is due to the 
sensitivity of area based matching to radiometric changes 
of the grey values. In multiscale, multitemporal, and mul- 
tisensor matching the corresponding assumptions are 
easily violated. 
The approach of Drewniok and Rohr (1995; 1996) was 
developed for urban large scale imagery. The authors use 
manhole covers as control points. Three-dimensional 
coordinates are available in a sewage cadastre. These 
manhole covers have a diameter of approximately 6 pixels 
and are assumed to exhibit a rotationally symmetric 
brightness pattern described by three parameters. These 
parameters are determined in a so-called learning phase, 
and the result is a template for the manhole covers. 
Detection of the manhole covers is then performed via 
least squares estimation between the templates and the 
image grey values. The used images show a large number 
of manhole covers, thus the aspect of redundancy can be 
exploited to advantage. In order to find the corre- 
spondence between the candidates for manhole covers in 
the image and the actual manhole covers in object space, 
a common scale factor is assumed, and a relational des- 
cription based on relative distances is constructed. Sub- 
sequently, relational matching is performed, followed by 
a spatial resection for computing the orientation parame- 
ters. A critical point in this well designed approach is the 
question how well the assumed radiometric model des- 
cribes the actual appearance of the manhole covers in the 
images. 
Relational matching was also used by Vosselman, Haala 
(1992). Large scale colour images were registered to a 
scanned map. The images were pre-processed using 
standard image processing routines (classification follo- 
wed by binarization, edge detection and line following), 
the maps were digitized manually. Subsequently, a rela- 
tional description of the image and map content was set 
up. The correct match was found using tree search me- 
thods. The method was tested with roads, rivers, and land 
parcels and yielded promising results. The third dimen- 
sion was not considered in the approach. 
308 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B3. Vienna 1996 
Dowman et al. (1995; 1996, see also Newton et al. 1994) 
use a similar approach. Their study on map registration 
of aerial and satellite imagery is based on polygons ex- 
tracted from the map and the image by means of edge 
detection and segmentation. The matching is carried out 
by dynamic programming using a description of the po- 
lygons based on shape, orientation, and area. Examples 
are given for forest areas, and large buildings. Also this 
method only works in two dimensions. 
Christmas et al. (1995) use probabilistic relaxation for 
matching road networks extracted from maps and im- 
ages, respectively. Both road networks are represented 
as attributed relational graphs. The nodes of these graphs 
are line segments. Only unary and binary relations are 
considered. Beside other findings the authors successful- 
ly show the rotation invariance of their sophisticated 
approach. Again, the third dimension is not dealt with. 
In an interesting approach Holm et al. (1995) use lakes 
and small islands for a completely autonomous orienta- 
tion for satellite imagery taken over Finland. This work 
has its roots in a prior publication by Holm (1991). Due 
to the specific Finish landscape an abundance of control 
data is available, and the third dimension plays a marginal 
role only. Water bodies of the images to be orientated are 
mainly extracted by thresholding the histogram of the 
near-infrared band, and are described in terms of area, 
perimeter, compactness etc. After using the satellite orbit 
data for a coarse geo-coding feature based matching is 
carried out using the descriptions of the water bodies. 
This step is followed by a robust estimation of the para- 
meters of a two-dimensional affine transformation. Suc- 
cessful tests are reported using Landsat TM, SPOT XS 
and NOAA AVHRR images. The system has been instal- 
led at the National Land Survey of Finland and the 
Environmental Data Center of Finland. 
Schickler (1992; 19952) has developed a module for ab- 
solute orientation for the production of orthophoto maps 
at the Landesvermessungsamt Nordrhein-Westfalen. 
The images are approximately of scale 1:12.000. Three- 
dimensional wire frame models of houses are used as 
control information. The work builds upon prior studies 
by Forstner (1988) and Sester, Forstner (1989). Assu- 
ming good approximate values for the orientation para- 
meters (+/- 50 m for the centre of projection and +/- 1 
degree for the angles) the wire frame models are projec- 
ted into the image, and a search space is defined. In this 
   
   
   
   
   
   
   
   
    
    
    
   
   
   
    
    
    
   
   
   
   
    
    
   
    
   
   
    
  
   
    
   
   
   
   
   
   
    
    
   
    
    
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