THE POSSIBILITY OF EXTENSIVE APPLICATION 
    
OF NON-METRIC CAMERA MADE IN CHINA 
Wang Li,Wang Qingting 
Associate Professor 
Institute of Seismology,State Seismological Bureau 
China 
Comission I 
ABSTRACT: The lens distortion of non-metric camera "Seagull" made in China is calibrated. It is found 
that the change of distortion coefficient (K1) in the process of photography of whole film roll is 
small. The photogrammetric accuracy of non-metric camera can be also improved by using the average 
distortion coefficient for correction. 
KEY WORDS: Non-metric camera, Film deformation, lens 
1 INTRODUCTION 
It is the conventional photogrammetry of non- 
metric camera that a few controls (often seven or 
more) in the object space are determined, then the 
camera parameters (including the lens distortion 
coefficient) along with the coordinates of unknown 
points are resolved using some analytical methods 
(for instance DLT). The photogrammetric accuracy 
of non-metric camera can be greatly improved by 
this way. However,it has a shortage that enough 
controls must be measured or the moving control 
framework supplied in each pair of picture 
. This has virtually limited the 
extended application of non-metric camera. 
As far as some photogrammetries with middle and 
low accuracy are concerned, could the non-metric 
camera be used like the metric camera with less or 
without controls? For this purpose,a series of 
tests of non-metric camera made in China are done. 
2 CALIBRATION OF NON-METRIC CAMERA 
Comparing with the metric camera, the non-metric 
camera has the main disadvantages, such as lack of 
the collimation mark and flattening device, The 
unstable internal orientation and the big lens 
distortion etc.. Some defects can be overcome, for 
example,the collimation mark can be cut 
artificially. The unflatness effect of film in 
non-metric camera is big, but contrasting with the 
effect of lens distortion,it is smaller. There- 
fore, we chiefly calibrated and determined the 
film deformation and the lens distortion. 
distortion, Average lens distortion coefficient. 
2.1 Deformation of Non-metric Film Made in China 
The black and white panchromatic film 135 and 120 
made in Shanghai Film Manufacturer are analysed. 
For the sake of determining the film deformation, 
the frame span in middle part of photograph is 
measured by paralleling the picture side with the 
comparator axis because out of the collimation 
mark in non-metric camera. Comparing frame spans 
each other, the change of film in the process of 
photography is understood. The change curves of 
film in 135 and 120 are separately shown in Fig.l 
and 2. It can be seen from figures that: 
(1) The change along x (roll direction) is greater 
than that along y for both films. The change along 
x and y in 135 film are 0.07mm and 0.03mm, and in 
120 film 0.05mm and 0.04mm respectively. The 
changes exceed the error of picture measurement. 
Thus the film deformation has to be corrected 
while the non-metric film is used for photogramme- 
try. 
(2) It is generally considered that the bigger the 
area of film, the larger the deformation. However, 
the deformation of film 135 isa little larger 
than that of film 120 from our test results. We 
infer it is possible that the  pulling-force 
supported in film 135 in use is greater than that 
in 120 because the former is twice as long as the 
latter. Also it can be seen from the curve of 
Fig.l that the deformation in both ends is smaller 
than that in middle part for 135, which indicates 
that the pulling-force supported in middle part of 
135 film roll is bigger than that in both ends. 
  
  
nm Length change along X 
36.37 
36.35 
À 
36.337 
] NO. of film 
36.31 d erae ld e «coi me ee ra > 
] 4 7 11 14 47 202224 27 30. 32 36 
  
  
Length change along y 
Fig.1 Change of film 135