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for this analysis; they showed low density differences and only a 
limited number of suitable objects. The low density differences 
caused the rejection of many edges because the scanning noise 
prevented the derivation of accurate and reliable modulation transfer 
function (MTF) data. However, some targets provided good density 
profiles, and MTF's. The limiting resolution values obtained from 
these are shown in Figures 1 and 2 by numbers 2. 
Hakkarainen included data obtained from 1:4000 and 1:8000 
aerial photographs of a bar-target on Kodak 2405 film with Double-X 
emulsion. These results are also added to Figures 1 and 2 and shown 
by the numbers 4 and 8 respectively. 
Several observations can be made from Figures 1 and 2: 
— Both lenses show pseudo-resolution: the Super-Aviogon lens 
several orders for radial bars in the corner areas, and the 
Pleogon lens first- and second-order pseudo-resolution for either 
radial or tangential bars for points distant from the center more 
than 8 cm. 
- Both lenses fully utilize the low contrast (1.6:1) resolving 
power of 50 1/mm of the Kodak Doubie-X emulsion on and near the 
axis, as shown by Tayman and Gliatti. 
- Gliatti's and Tayman's data agree reasonably well with each 
other; Hakkarainen's data from aerial photographs are always 
lower. The cause of this has not been investigated. It could 
be one or a combination of forward image motion, atmospheric 
effects and camera vibration. The latter source seems to be 
responsible for the larger spread between the Gliatti-Tayman 
results and the Hakkarainen results observed for the RC8 
photography, indicating that improvements could possibly be 
made to the RC8 mount. 
Figures 3 and 4 give an overview over modulation transfer function 
data obtained during the course of the working group project. These 
figures are for lens angles up to 35° taken from Rosenbruch [6]. 
The presentations for the 45° lens angle are based on values by 
Hakkarainen [4] and Martin [5]. . Gliatti's results [7] are not 
included in these figures because the evaluated edges in general 
were not in a position and orientation to permit direct comparison 
with the other results. Although these resuits show a larger spread 
of measurements than the others, they agree well with the other results 
for the lower frequencies where the threshold detection value for the 
Kodak 2405 Double-X film is significantly smaller than the modulation 
transfer value.