International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol XXXV, Part B-YF. Istanbul 2004 
following equation. The equation was derived from the 
coplanarity condition equation. 
B 0 0 
yw 
u v wi=B 120 
; y ow 
H V w 
(1) 
Where 48 , V, W are coordinates of image point a in 
Y ru z - ' A, y : = 
S— AYZ spatial coordinate system. # , Ÿ , V are coordinates of 
image point a’ in | $ -XY Z spatial coordinate system. B is 
photo base, and the coordinates system is just described by 
figure 2. 
Supposing photo base B is collinear with the X axis of the 
coordinate system, so the component of photo base B is 0 in the 
direction of Y and Z. So equation |! can be denoted as follow. 
Flp.x,0 0 x)= , ; =0 
(2) 
Linearization of equation 2 is as follow. 
  
Zz 
Ziviy 
NY 
gn pi V 
B 
(u,v,0) y (uv J | 
Figure 2. Relative orientation relationship 
GF 
F(o.x,o 0k )= F SE oet AD RU au eU air MANY =0 
op Op ow 
Where, Q? , K are pitch and yaw of left image, Q' ; K' are pitch 
/ 
and yaw of right image, €^ is the roll angle of right image 
relative to left image. 
Using a number of tie points the absolute values of pitch and 
yaw can be calculated through this relative orientation 
algorithm. But the absolute roll angles cannot be computed only 
using two adjacent images. So the absolute yaw angle can be 
computed by one of these two ways, one is to import at least 
one GCP. The other, when there are four or more images which 
OK OK 
have longitudinal overlap and lateral overlap, the yaw angle of 
left or right image can be computed by using of these four- 
image-overlap points. And so as to implement the attitude 
angles computation without GCP. So after gotten the satellite’s 
position by GPS and the attitude angles using the images 
overlap characteristic, the targets’ can be positioned. The flow 
is described as follow(see figure 3.). 
  
  
Corresponding points 
surveying in overlap area 
  
  
  
  
Attitude computation 
  
  
  
Y 
  
Corresponding image 
  
Surveying the target in 
both images 
  
——» Attitude correction 
I 
I 
I . . 
-_a points surveying 
+ 1 
1 
  
  
  
  
  
  
  
Scale coefficient computation 
NED RT A en I 
v . Surveying the target in | 
: left image : 
1 1 
i 1 
  
  
  
Y I 
  
  
Target coordinate computation 
  
  
Figure 3. targets' positioning flow 
110 
Interr 
——— 
Two 
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