lows 
ate. 
ns C4 
5 
| COS« 
  
, 7000 
,0019 
,0312 
  
,5683 
,0014 
,0198 
on- 
| we get 
Once the parameters of light fall - off are known, compensation of 
this particular effect can generally be executed analytically. This 
affords, however, images in digital form. The formulas have to be 
applied in the negative sense defining the image center as the oriain 
of o with D = 0, neglecting the linear part. 
5. Digital Reproduction of the Light Fall - Off Phenomenon 
General advantage of a rigorous analytical approach is the possibility 
to analyse the behavior of a phenomenon theoretically. For the problem 
discussed here this means, that we can reproduce the measured conditions 
digitally. Moreover the particular effect caused by an additional 
linear disturbing function can be demonstrated. Two examples are dis- 
played in Fig. 7. 
The study of light fall - off in camera lenses is a limited, but 
necessary step with regard to describe the image grey values as à func- 
tion of the object characteristics properly. The LAMBERT reflector used 
for full frame calibration here, can be applied beyond that in order to 
determine the reflectance factor of particular objects and thus provide 
another contribution to the entire complex. 
   
b 
ight fall-off components for the evaluated 
a 
Fig. 7: Simulation of 1 
configuration (f - 5.6) 
a) Radial component ( C4 - 0.6229 ; c2 7» 0 ) 
= 0 3 Co = 0.00194 ) 
b) Linear component ( C1 
The steps correspond to the following densities [p] : 
  
  
  
  
  
, MM | 
hd t dl |