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LINEAR GEOMETRIC PARAMETERS 
Different kinds of geometric parameters could be chosen. At Stuttgart 
University the use of affine parameters have been reported (Pertl, 1984 
and 1985). 
If we have knowledge of the relative orientation parameters we can 
transform the images to epipolar geometry, the geometric correction 
only has to be applied in the x-direction, giving a four parameter 
geometric solution, where the parameters P, to p, are used. 
LINEAR RADIOMETRIC PARAMETERS 
The radiometric differences in absolute level and in contrast were com- 
pensated for with two unknown radiometric parameters one additive and 
one multiplicative, or in some cases with only a multiplicative parame- 
ter approximately corresponding to differences in overall exposure. 
MULTI POINT MATCHING 
A limitation, especially with automatic parallax measurements performed 
with matching methods, but also with manual measurements, is the diffi- 
culty in making measurements in areas with low signal content. Common 
matching methods, measuring one point at the time, are incapable of 
computing a parallax in such an area. I will here formulate a method 
which makes it possible to simultaneously compute the stereo parallaxes 
in grid points, which are connected with bilinear finite elements 
We could formulate the method with the following geometric bilinear 
transformation 
x AT. En as e? x) Ge vi Yl 
+ Pin gs A x.) Gor Vs 
: B iode ied Xe) Uy ^ A 
  
    
+ 0 
  
(Mic XL 
S 
i! by - y;! / 
i+1,j+1 
/ 
/ [Lun N y jh 
  
for 
Xi X X X +1 and y j^ y Yi] 
and 
yn iSi. 
where 
pio = the unknown parallax in the point i,j 
The points, in the rectangular grid are connected by bilinear functions 
in the stereo direction (the x-direction). We could now formulate the 
observation equations as 
D.5.Ap. ^ .* b. .Ap 
; +1b = :Al 
14) 14+) 1+1,3 .1*1.3J i,3*1 
BD, 135 DEP 1 APE 1 341 
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