2.05m and 
ers. Table 5 
ccuracy for 
> additional 
Sometimes, 
bject points 
ength of the 
as the usual 
| using side 
25 m object 
"he last pair 
for the four 
y the fourth 
= 
S | 
à. 
zZ 
E 
Z 
7 
  
  
, three, four, 
added in the 
n was added 
gher than the 
on similar to 
Ali, Mahmoud El Nokrashy 
Table 7 shows the results of the test. From the table it can be seen that increasing the number of camera stations 
improves the accuracy. When six cameras were used the accuracy is improved compared with the case of two cameras 
by 31%, 60% and 28% in X, Y and Z respectively. 
  
  
  
^ gt JT" 
— Àá— - » 
2.05m 
Three Camera Stations 
Lar 
Four Camera Stations 
ve 
__| 0.25 m nit Xe 6 
dior arms Sin cy 
2 1 2 
* e 
  
  
T 
  
2.05 m 2.05m 
Five Camera Stations Six Camera Stations 
Fig. 2- Arrangement of Camera Stations. 
Table (7) Average Errors for Check Points Against Number of Camera Stations. 
  
  
  
  
  
  
  
  
  
Case of Average Error (cm) 
Study SX SY SZ ST 
Stereo — Pair 3.33 3.13 6.63 8.05 
Three-Station 3.11 2.42 6.11 7.27 
Four — Stations 2.87 2.03 5.63 6.64 
Five — Stations 2.51 1.69 5.19 6.01 
Six — Stations 2.29 1.25 4.81 5.47 
  
  
  
  
  
4- CONCLUSIONS 
From the results of the research the following conclusions can be drawn 
1 - 
N 
It is possible to obtain 10cm accuracy in position, for targets at 55m from the cameras, 
if close range 
photogrammetric system similar to one we used is utilized. 
Increasing the base line length increase the accuracy significantly especially in Z direction, which could reach 40%. 
The authors suggest that, two sliding cantilevers can support the two cameras for a MMS. The length of these two 
cantilevers can be controlled automatically using a motor operated from inside the van according to the width of the 
road. 
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B5. Amsterdam 2000. 23