A STUDY ON THE DEVELOPMENT OF SEMI-METRIC CAMERA 
FOR VERY CLOSE-RANGE PHOTOGRAMMETRY 
W.J. Oh 
Dept. of Cadastral College of Chungcheong 
Cheongjoo, 363-890, Seoul, Korea 
SH Han 
Dept. of Civil Engineering 
Cheonan National Technical College 
Cheonan, 303-240, Seoul, Korea 
SH Song, SH. Bas, 
H.S. Lee 
Dept. of Civil Engineering 
Chungnam National University 
Taejeon, 305-764, Seoul, Korea 
Commission V, WG 2 
KEY WORDS: Metric, Non-Metric, Camera, Calibration, Very Close-Range Photogrammetry, Bundle Adjustment 
ABSTRACT 
As for the non-metric camera, the control of focal length is free, and it is free from restraint about minimum 
object distance. So, if the inner orientation parameter is solved, prompt photogrammetry will be able to be possible. 
In this study, this researcher obtained the inner orientation parameter of non-metric camera by means of 
collimator method. And this researcher calculated with bundle adjustment, by photographing the small size object with 
very close range. And, then, this researcher tries to suggest the optimum photography condition of very close-range 
photogrammetry, by analyzing the feature of r.m.s.e based on the change of convergent angle, control point and 
number of photographs etc. In addition, this researcher tries to solve the difficult problem of control surveying, by 
devising and applying the self-control point system. 
As the result of study, as the superiority of very close-range photogrammetry by non-metric camera and the 
applicability of self-control point system could be proved, the utilization is expected for the precise measurement of 
small size object. 
1. INTRODUCTION 
As the metric camera is expensive, it is difficult to 
compose the multi-synchro shutter system. And, as it is 
heavy, the treatment is inconvenient. Besides, as the 
focal length is being fixed with several units, it is 
restricted about minimum object distance. Thus, there is 
the limit in the very close-range photogrammetry. 
However, as for the non-metric camera, the price is 
cheap, the treatment is easy, the control of focal length 
is free, and the limit about minimum object distance is 
small, in comparison with metric camera(Fraser1982, 
Fryer1985, Hatzopoulos,1985). So, it is suitable for the 
very close-range photogrammetry, if one executes the 
lens calibration. As for the metric camera, the distortion 
is small, and the inner orientation parameter is offered. 
So, the precise 3-D measurement from camera is 
possible. But, as there is not the inner orientation 
parameter in non-metric camera, the study for solving 
the point at issue efficiently must precede(Fioretti, 1985, 
Light, 1991, Fryer, 1992). 
In this study, this researcher tries to develop the 
non-metric camera into semi-metric camera, by 
manufacturing and installing the glass plate fiducial mark 
426 
in the mount of non-metric camera and extracting the 
principal point of autocollimation, the principal point of 
symmetry, and the equivalent focal length, the calibrated 
focal length and the lens distortion coefficients etc, by 
collimator method. By applying this to the practical 
experiment, this researcher tries to examine the 
usefulness of semi-metric camera through the r.m.s.e 
analysis based on number of photographs and 
convergent angle, convergent angle and number of 
control point, and object distance and number of 
photographs and to solve the difficult problem of control 
surveying by self-control point system. 
2. COLLIMATION TEST 
As there is not the fiducial mark in non-metric 
camera, this researcher manufactured the glass plate 
fiducial mark so as to obtain the exact photo 
coordinate(Fig. 1). This researcher attached the 
manufactured glass plate fiducial mark to the mount of 
non-metric camera, so that the central fiducial mark of 
it may be situated at the principal point. 
International Archives of Photogrammetry and Remote Sensing. Vol. XXXI, Part B5. Vienna 1996 
  
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