The International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences. Vol. XXXVII. Part Bl. Beijing 2008 
375 
W ‘ -Uif + ( v -V/) 2 
Where Z,:height of the point clouds 
u u v,: image coordinates of the point clouds 
: hight of the interesting point 
u, v: image coordinates of the interesting point 
tfl, 1 
0 
H 
1 
A 
0 
N 
1 
¿*31 1 
0 o 
1 1 
A ^ 
•+Æ32 1 
l+ a 2 2 ( 
M„) 
[r-r.) 
>+ aj 
,+ a 2 3 l 
N N 
1 1 
N N 
O O 
031* 
1 
o 
l+ tf 3 2 ( 
lr-r») 
l+ tf33 ( 
N 
1 
N 
O 
where u, v: image coordinates 
/: focal length 
: rotation matrix 
X, Y, Z: ground coordinates of interesting point 
X 0t Y (h Z 0 : exposure station of platform 
Figure 2. Flowchart of pseudo GCPs generation 
the triplet images were generated 3 stereo pairs, interesting 
point P(X,Y,Z) has different 3 ground coordinates for each 
stereo pairs which are shown in Figure 3. 
Therefore, triplet restriction was applied so that the each 
residual AP for the X,Y,Z become minimum in calibration 
procedures. Here, each residual AP are computed from 
equation (4). 
AP AB P ave. P AB 
AP BC~ Pave - P BC 
(4) 
AP AC ~ Pave. - P AC 
p Zw,p, 
Zw, 
where, ground coordinates of the interesting point 
APÿ : differences of each stereo pair 
lF,:weight of each point 
ABC 
4. EXPERIMENT 
3.3 Data acquisition 
In order to confirm the validity of the proposed simultaneous 
adjustment, data acquisition was performed in our test field. 
Test field has 117 GCPs, and 26 GCPs can be utilized in triplet 
area. GCPs were obtained by static observations using GPS that 
were set on the edge of road paints. Table 1 shows data 
component which used in this investigation, and Figure 4 shows 
the centre image using in this investigation. It was taken with 
about 1270 m, and photo scale is about 1/21,000. Therefore, 
GSD (Ground sampling distance) shows about 20cm. 
Figure 5, 6 shows GCP image, and it can be realized that image 
quality is not clearly. Pointing were performed in each 
calibration with 1/1000 pixel accuracy, but it is speculated that 
pointing accuracy haven’t 1/1000 pixel accuracy. 
3.2 Simultaneous adjustment 
In order to improve the calibration accuracy, triplet restriction 
was adopted into the calibration using Pseudo GCPs. Due to