testing. Study efforts at P-E cover both the fundamental and 
practical aspects of optical frequency response, The topics con- 
sidered include the significance of OTF phase, shutter diffraction 
effects, image quality measures, edge gradient analysis and photo- 
graphic nonlinearities. 
5.9.4.2 OTF/MIF Studies and Applications: 
Augustyn”? reports the use of interferometers coupled 
with computers in analyzing the wavefronts transmitted through 
optical system. The technique allows separation and thus analysis 
of individual aberrations. 
Jones and Trinks®0 analyzed the source of image degradation 
in contact printing, finding the near-field diffraction effect 
significant, such that linear analysis may be invalid. They 
reported that diffraction was compensating for the expected loss 
in edge shapness. Edge gradient analysis showed little modulation 
loss in contact printing while a resolution loss attributed to 
increase in granularity was observed. 
Jones! says that significant errors are introduced in 
making photogrammetric measurements without correcting for non- 
linearities. The visual location of image boundaries which is 
confused by photographic blur and granularity can be eliminated 
by averaging techniques. However, photographic nonlinearities 
can distort boundary density profiles and produce systematic errors 
which cannot be eliminated in this manner. The two significant 
photographic nonlinearities which Jones considers are the sensito- 
metric properties of the original and duplicating films and the 
near-field diffraction associated with contact printing.  Investi- 
gation showed such errors to be significant so a technique was 
developed to automatically determine dimensions from the photo- 
graphic images, functioning in the presence of linear and nonlinear 
degradations and photographic granularity. Tests show the technique 
produces accurate measurements for laboratory and operational 
cases, and measures and corrects for camera MTF. 
Mantagninc?? notes that the focal plane shutter is fre- 
quently employed in aerial cameras for the purpose of minimizing 
the degrading effects of image motion during exposure, but the 
diffraction effects can negate imige motion, making motion analysis 
requisite. He derives a general solution for the diffraction 
effects of a focal plane shutter and its interaction with uniform 
linear image motion. The solution shows that the shutter/motion 
interaction is dependent upon size and shape of the pupil and 
the optical aberrations, whereas shutter and motion effects are 
independent of these parameters when considered separately. In 
lieu of an explicit solution, Mantagnino derives an expression 
for the upper bound performance. 
25