1.4 - CONDITIONS OF ADJUSTMENT OF THE TYPICAL CAMERA. 
Let us consider (see figure 1a), a point of the ground Q, and its image 
q. On the cylinder we oonsider the track r of the plane normal to the axis of 
the camera, passing through the internal nodal point of the lens (cylinder di 
rectrix), and the track s of a reference plane passing through the axis of the 
camera. The position of the point q is defined on the cylinder by the value. 
of x' (this is the distance between the direotrix containing the internal no 
dal point and the directrix containing the image a), and by the value off 
(angle that the generatrix s forms with the generatrix on which the image q 
is found). ; 
Since in the formation of the image q only the center of the lens and 
the ground point Q, are involved it can be observed that, by leaving out of 
consideration the conditions of the best foous of the images, the disalign 
ment of the rotation axis of the lens and the axis of the camera does not 
bring along any displacement of the images. The question of the disalignment 
of the rotation axis of the lens or of the slot axis, is therefore of no im 
portance if the photogram is taken under static. conditions of the camera. 
Instead, if a photogram is taken under variable orientation conditions 
of the camera, the disalignment of the axis does not permit the correct attri 
buting of the external orientation parameters to every internal direction. 
We shall then see that the independent variable by means of which the 
movement of the camera is described, is the scanning angle y .. If the axes 
of the camera are disaligned, to a given value of the scanning angle y, va 
rious values of P correspond, so that, even in the correct position, the ima 
ges of the points are exposed before or after the soanning angle has assumed 
the value f. | 
In other words, since in dealing with the space resection problem of a 
panoramic photogram it is necessary to take into account the variability of 
the external orientation parameters, it is necessary to establish which are 
the images that have been simul taneously impressed on the photogram, For the 
axes disalignment effect, the images placed on a generatrix of the cylinder 
and characterized by the same f value, are impressed at various times and in 
correspondence with various X values. If the law of movement of the camera 
is described as a function of y and if it is assumed that f =X, an error de 
rives in attributing the external orientation parameters to each impressed 
image. 
From these considerations derive the following adjustment conditions 
for a typical cameras 
a) the rotation axis of the scanning should pass through the interior nodal 
point; : 
b) the rotation axis of the scanning should coincide with the axis of the ca 
mera; 
c) the slot rotation axis should be parallel to the scanning rotation axis; 
d) the IMC axis should coincide with the axis of the camera: variations of 
the parameter p are avoided. 
  
M,