The constant light will then form a thin line between all the stroboscope 
points from each signal. To identify the different signals belonging to 
the same stroboscope flash an extra flash from an electronic flashlamp 
can be used. 
Calculating the velocity according to formula (1) gives corresponding 
values of v and t. The function is adjusted according to the method 
of least squares supposing a third order polynome: 
v —a + bt + et2 + dt3 (3) 
When this function is known the deceleration can easily be found: 
For known values of the deceleration the force can be calculated 
according to the wellknown Newton formula. 
The measuring of the stretching of the band has a standard error of 
0,5 mm. The relation between the force and the stretching is often 
determined at "static" loading but with this method the relationship can 
be obtained at dynamic loading. 
References: 
(1) Hallert, B.: A new method for the Determination of the Distortion and the 
inner orientation of Cameras and Projectors. Photogrammetria XI 
1954—1955, 3. 
(2) —— Determination of the accuracy of terrestrial stereophotogrammetric 
procedures. Photogrammetric Engineering March 1955.