Istment 
out minimum 
e possible. 
)y means of 
'e object with 
/ close-range 
rol point and 
surveying, by 
nera and the 
'asurement of 
extracting the 
yal point of 
the calibrated 
ents etc., by 
the practical 
examine the 
h the r.m.s.e 
graphs and 
] number of 
| number of 
lem of control 
n non-metric 
3 glass plate 
exact photo 
attached the 
the mount of 
lucial mark of 
  
  
| Photography of fiducial mark 
fru: (Rollei Metric s System) 
ft Acquisition of Negative Picture | 
| 
E Manufacture of Positive Picture 
  
(ASA 25 rith film) 
| 
E Contact Print | 
| (Positive & Blank Mask) 
| Development of Exposured Blank Mask | 
| | 
  
  
  
  
  
  
Chack | 
| 
| Cr Etching iid 
I 
| 
a END o 
  
Fig. 1. Manufacture of glass plate fiducial mark 
2.1 PPS and PPA 
In case of correction about the lens distortion, one 
must know the exact radial distance. Radial distance is 
not the distance from the origin of photo coordinate, but 
it is defined as the distance from the PPS(principal point 
of symmetry) of lens distortion to the image point. So, 
one may correct the distortion, only in case that one 
knows the principal point of symmetry. As for the view 
  
Collimator images 
NTL 
  
  
  
  
  
  
A 
      
  
  
  
  
File format 
  
  
  
Horizontal test 
Vertical test 
Fig. 2. Calibration of lens by collimator 
angle of NIKON F-801 non-metric camera(f-35 mm), 
the horizontal direction was about 50° , and the vertical 
direction was about 33° . Therefore, this researcher 
photographed 9 units of collimator images respectively, 
by revolving the collimator by 6° toward horizontal 
direction and by 4° toward vertical direction(Fig. 2). 
This researcher obtained the principal point of symmetry 
by averaging the difference of radial distance about 
horizontal direction and vertical direction(Fig. 3). 
In installing the lens in camera, the center of lens 
and center of photo is not coincident. So, one must 
make the correction about this. As for the displacement 
amount, this researcher obtained the PPA(principal point 
of autocollimation) by observing the radial distance to 
each collimator image and observing the displacement 
amount of 0° collimator image about central fiducial 
mark, in the collimation test(Fig. 4). 
Image point 
  
   
   
Radial distance by PPS 
o 
Principal point 907 € 
Hl RS 
+ 7pm 
  
Principal point of symmetry 
  
  
Il S Symmetry axis by PPS 
Fig. 3. Principal point of symmetry 
  
+103um 
  
(Collimator shift angle = 0) 
  
  
  
  
Fig. 4. Principal point of autocollimation 
22 EFL and CFL 
As for the EFL(equivalent focal length), we obtained 
( I Ah 3l AIV A) 
tan 0 : 
  
36.266mm by’ EFL = as 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996