X 
N 
        
      
  
LINE INTERSECTION OF TWO PLANES 
18 RAY TO POINT 
4 
  
CAMERA STATION 
/ 
A ZELDA = 
    
  
/ 
Z 
/ 
Mm re tv ar tr mm eit 
Figure 10. Principle for determination of the line of sight to a point in object space. Two image planes are recorded 
by photography on two different camera axes from the same camera station. The line of sight - or ray - is the intersection 
of two planes, each determined by one camera axis and the line extending outwards from the principal point of that image 
plane to the image of the point. 
Conclusion 
Radial error caused by lack of flatness of photogrammetric plates and emulsions is 
irregular and unpredictable, defies calibration and is particularly evident in the wide-angle 
photography of architectural subjects. Relying on camera calibration of the principal points in the 
image, on accurate survey of camera positions and axes, on targetting of the camera horizon in 
object space with survey control measurements in this same plane an organization of photographic 
procedures in the field has been proposed to substantially eliminate radial error - and the large 
standard errors of measurement it causes - from analytical photogrammetry of architecture. 
References 
[1] Borchers : "Choice of Station and Control for Efficient Orientation and Plotting in Architec- 
tural Photogrammetry'', Photogrammetric Engineering, December, 1960. 
[2] Helming : "Control and Improvement of Camera for Architectural Surveys', Royal Institute 
of Technology, Stockholm, Sweden, August, 1960. 
[3] Borchers : "Supplement to the Photogrammetric Study of Structural Movements in Architec- 
ture", Royal Institute of Technology, Stockholm, Sweden, August, 1964. 
[4] Borchers : "Photogrammetric Measurement of Structural Movements', Journal of the 
Surveying and Mapping Division, ASCE, January, 1968. 
[5] Borchers : "Trois Types de Mesures Photogrammétriques Utilisées en Architecture" 
Bulletin No. 19, Société Francaise de Photogrammétrie, July, 1965. 
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