e 
e 
-5- 
Now, after these general descriptions the method will be further 
explained with the special testfield which had been set up in 
the Niedersachsen Stadion at Hannover /1/, Abb. 1. Some expe- 
rimental data will be included. The calibration had been carried 
out for the camera PHOTHEO 19/1318 from Carl Zeiss, Jena. 
The experiments had been performed to investigate two interde- 
pendent questions: 1. How many points and what size should the 
testfield have? 2. Can the number of testfield points be re- 
duced by increasing the photogrammetric informations? 
For this, three different testfields with points of very high 
accuracy are used (see Abb. 2, 3 and 4 in /1/): 
TESTFIELD 1: Abb. 2 shows testfield 1 after having taken 5 
photos at different inclinations c5. So, a set of 
5 photos is necessary to fill up the format of the 
camera with terrestrial points. In Abb. 2 the points 
of each individual photo have their specific symbol: 
Ti,O,AÀ, + and x respectively. 
The number of points per image is about 69, the 
total number for the camera plane about 5 times 69. 
Testfield 1 will only be used to check the following 
ones. 
TESTFIELD 2: Thinning out testfield 1 down to two rows of about 
: 28 points we achieve testfield 2, see Abb. 5. This 
field is more realistic for practical applications. 
TESTFIELD 3: It contains only one row of about 13 points. This 
is the desired final testfield size. 
The set of 5 images to cover the whole camera format with ter- 
restrial points will be called a series of images. As has al- 
ready been mentioned several photos will be taken for one camera 
orientation. According to the investigations of HOTTIER /1/1976 
up to three series of images are introduced.