TION: 
latching, 
2ck their 
oped by 
ceted by 
regions 
whether 
nitor the 
ratching 
ints are 
ses and 
ystems, 
bility to 
parison 
»aklines 
pes was 
e DTM 
tests for 
poor in 
y due to 
ich was 
e scene 
timised 
/ dark). 
with a 
ificant 
images 
om one 
; DTM 
ids for 
points. 
hereby 
hnique 
sults of 
irhood 
grid in 
thus, a 
ystems 
ies. In 
- DPW 
  
Fig. 1. An image region from the second pyramid level. Pixels in white have grey value zero. Left: the original image ; 
Right: after Wallis filtering. 
  
Fig. 2. 3D parallel view of the Morteratsch glacier (exaggeration factor 1.5). 
the steep_1 strategy). In VirtuoZo the patch size that was used for 
crosscorrelation was 9 x 9 pixels and the distance between match 
points was 9 pixels, i.e. ca. 2.7 m in object space, resulting in 
467,000 match points. In DPW 770 the patch size is selected 
automatically based on the strategy and the pyramid level (in our 
105 
case 15 x 15 pixels). The selected DTM grid spacing was 2.5 m 
resulting in ca. 462,000 DTM points. VirtuoZo used four 
pyramid levels (incl. the original image) and the DPW 770 eight 
processing passes that included six pyramid levels (for some 
pyramid levels there are double processing passes). 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B4. Vienna 1996