4 
GIOVANNA 
TOGLIATTI 
a) Study on the accuracy of the analytical bridging between the photo 
grams of a strip depending on the position and on the number of points which 
are used for relative orientation and scale transfer. 
b) Research of the systematic errors of relative orientation of the photograms, 
due to local deformations of the plates, which vary from plate to plate. 
c) Research of the systematic errors in the model formation, namely in the 
position of the image-points, due to asymmetries characteristic of the bundle of 
rays produced by the objective lens and, therefore, equal in all the plates. 
In the following paragraphs we shall give a detailed account of the way in 
which the research concerning the above mentioned subjects was set up, the pro 
cedures we followed and the results we obtained. 
2. — The study of the intrinsic accuracy of the bridging between photograms, 
depending on the position and on the number of points used for relative orientation 
and for scale transfer, constitutes the intermediate phase of a larger program of 
investigation on this subject, which, so far, has been only partially accomplished. 
We must point out that this problem can be laid down only in the field of nu 
merical Photogrammetry that allows a greater freedom in the position and number 
of the points for orientation and transfer of scale, in comparison to analogical 
Photogrammetry, where we are more bound in the choice of them. 
On the first phase of the investigation, now ended and published [i], we 
shall give here only a short account. In that investigation we analysed the mean 
errors of the orientation parameters, depending on the number of points we used 
and on their position on the model. It dit not imply real measurements on the 
plates, but only the study of different geometric schemata, whose structure determi 
nes the value of the weight cofactors of the unknown parameters of orientation ; 
the weight cofactors then permit to obtain the mean errors of the unknowns, once 
the values of the accidental measure errors are given. 
The second phase of the study concerns the analysis of the intrinsic accuracy 
of real strips, from the view points of the values of the residual parallaxes after 
the relative orientation, and of the deviations between models. 
A short information on it was given at the SIFET Congress in 1963 [2]. How 
ever, at that time, the analysis of the results was not yet finished, so that we could 
only confine ourselves to generical information on the way in which the experiment 
had been executed. 
The five strips constituting the block were triangulated according to an ana 
lytic procedure [3], which requires the measurements of the plate coordinates of 
the orientation points and of the known points to be executed with a three carriages 
stereocomparator. The bridging computation is based on the solution of a set of 
simultaneous equations of the following types : 
4? — A, 
(1) 
Vi 
(2) ,(1) 
t {1) — t 
VX: V 
(2) 
by 
v 
1 X: 
(1) j(2) 
tv t 
e-t. 
(2) 
= o