apeCapture and 
olar geometry as 
nters of the two 
yipolar plane) that 
ult, two epipolar lines 
hese lines. Once the 
two image locations 
lines become known. 
ate pl in the left image 
e in the right image. 
on the same line, we 
we select the 
  
Viodel 
set the digital image 
ed into the memory 
> program automatically 
argets extracted, stereo 
d the file closed in 
set is opened. The 
e configured for the 
ended. 
neasurement of thin skin 
cuum chamber but it 
static subjects. 
SURFACES 
es presents problems 
iques such as retro 
ial can sometimes be so 
age the material 
o if the object is 
ated) over a period of 
r the targets during 
membrane where 
tored. Figure 8 displays 
leviations and wrinkles. 
  
  
Figure 10 Clear membrane and frame 
Figure 7 Thin Membrane targeting and measurement 
Figure 9 illustrates the setup method to overcome this problem 
the cameras are mounted behind the membrane where the 
projected target pattern is displayed shown in Figure 10. Figure 
11 shows the measured area before and after the multi target 
feature selection. 
Figure 8 Surface plot of membrane surface 
In addition to the problems encountered in the more 
conventional photogrammetric process, other measurement and 
data acquisition systems such as laser based systems have 
problems with thin membrane surfaces. Some of the problems 
occur with the color of the membrane, with the more difficult 
to work with is a clear membrane. The projected target will 
disperse through the medium, example of this can be seen in 
Figure 2 around the headlamp assembly. In Figure 9, 10, a clear 
thin membrane is mounted and stretched on a custom frame 
mount made of clear Plexiglas. 
  
Figure 11 Multi target tool 
The software allows for various image-processing schemes for 
target and edge measurement. In this case tiny solar cells were 
embedded in the clear material which made auto threasholding 
and measurement difficult as shown in Figure 12 on 
illuminated areas. The software allows for intervention and 
even allows for circle measurement options for just this case. 
Figure 13 shows surface plot of clear membrane example. 
  
Figure 9 Clear Thin Membrane 
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