1 08 180 
XIII. Congress of the International Society for Photogrammetry 
Helsinki 1976 
Commission 1, working group image geometry 
Presented Paper 
Considerations of image geometry and image quality of lenses 
in aerial mapping cameras 
von K.-J. Rosenbruch, Physikalisch-Technische Bundesanstalt 
Braunschweig, Germany 
Summary 
After a short review of the purposes and methods of testing 
optical systems, the importance of OTF«measurements for the 
evaluation of image quality is emphasized. The disadvantage 
that carefully designed and highly sensitive instruments are 
required, and the difficulties in realising the desired quality 
criterial from the large number of data are discussed. With 
regard to the efficiency of aerial mapping lenses there are 
two important points: correct image geometry and good image 
quality. In practice the emphasis was laid hitherto on exact 
geometry for the usual photogrammetric purpose. But with greater 
measuring accuracy and better performance of the lenses with 
regard to distortion, knowledge of the image quality of the 
lenses and of the influence of other camera parameters and flight 
conditions is necessary in order to exploit this accuracy practi- 
cally. The procedure of cascading OTF-curves of the various 
components is a good method for dealing with some of the problems 
which arise when tests carried out in the laboratory are to be 
adapted to the actual practical conditions. 
For aerial mapping lenses, some examples are.given showing how 
to reduce the number of the necessary OTF-curves by using field 
curvatures as an additional means of testing the image perform- 
ance. Some OTF-values and field curvatures of old and new lenses 
and cameras are demonstrated. The possibilities of deriving 
figures of merit from OTF-data are discussed.