CONTRACT (Sanitized)

• Document Type: CREST
• Collection: NGA Records (Formerly NIMA)
• Document Number (FOIA) /ESDN (CREST): CIA-RDP78B04747A002900030012-5
• Release Decision: RIPPUB
• Original Classification: S
• Document Page Count: 7
• Document Creation Date: December 28, 2016
• Document Release Date: June 19, 2002
• Sequence Number: 12
• Publication Date: May 19, 1966
• Content Type: LETTER

Approved For e~eeease 2002/07/10 : CIA-RDP78BO4747AO02900030012-5
Nor
Tits Document Consists of-L_-Pages.
Copy No. of Copies.
May 19, 1966
Enclosed please find three (3) copies of our Sixth Monthly
Evaluation (T3), for the period covering 15 April 1966
1966, dated 18 May 1966. 'T'his roport is being submitted
under subject contract.
Sincerely yours,
25X1
BJT;nvb
Encl.
DECLASS REVIEW by NIMA/DOD
't'his document contains information affecting
the national defense of The United States within the
meaning of the Espionage Laws, Title 18. U. S. C..
sections 793 and 794. Its transmission or the rev-
elation of its contents in any manner to an
unauthorized person is prohibited og law.
SECRET
G-ROi ; P..1
Excluded from automatic downgrading
and decfa,sifICatiora.
Approved For Release 2002/07/10 : CIA-RDP78BO4747AO0290003001
 25X1 Approved For Release 2002/07/10 : CIA-RDP78BO4747AO02900030012-5
Approved For Release 2002/07/10 : CIA-RDP78BO4747AO02900030012-5
 25X1
Approved Fa elease 2002/07/10 : CIA-RDP78B047 1002900030012-5
SIXTH MONTIILY LETTER REPORT ON EVALUATION
1. Work for Reporting Period
During this past work period we have made measurements to determine
the incoherent modulation transfer function of the enlarger system. This was
done to determine how close to diffraction limited the lenses are. The following
procedure was used. Using a precision edge of 3. 5:1 contrast as the object,
and moving a piece of finely ground glass directly in front of the object to re-
duce the ratio of coherence interval to lens spot size to approximately one,
images were obtained. This was done for both the He-Ne laser source and the
Na source. The edge image was then traced on the microdensitometer and the
trace data used in the computer program. Figure 1 shows the results for the
laser source and Figure 2 for the sodium source.
This procedure was then repeated with the object plane slightly shifted
from the plane of best focus. This was done to determine exactly how critical
the focussing is in terms of its effect on the incoherent modulation transfer function.
Results show that for object plane shifts of ?0.0005" there is a negligible change in
the transfer function while for a shift of ?0.001" (Fig. 1) there is a small but not
negligible loss of modulation over the spatial frequency passband. These object
plane shifts correspond to ?0. 008" and ?0. 016" shifts in the image plane, respec-
tively, since the depth of focus increases as the square of the magnification.
Approved For Release 2002/07/10 : CIA-RDP78B04747A002900030012-5
 25X1
Approved Fo - 02900030012-5
We have recently obtained experimental results showing the shape of
edge images for partially coherent illumination. These are now being evaluated
and cclzpared directly with the images predicted. on the basis of computer calcu-
lations.
The computer calculations of the expected images of
"L" 25X1
targets have been obtained and the experimental images show qualitative agreement
with these calculated images. Quantitative differences do exist, however, and it
is felt that this is due to the restricted number of sampling points available in the
computer program. As more points become available the interaction of each three
bar group with the adjacent groups can be taken. into account and a better approxi-
mation to the actual partially coherent imaging situation can be obt ained. Work is
now continuing on this extension of the computer program.
The theoretical results obtained for low contrast objects were mentioned
in the last letter report. Since then we have also shown theoretically that when
the amplitude transmittance of the object is locally constant over distances on the
order of the coherence interval a partially coherent imaging system becomes linear
in intensity. We are now investigating the implications of this result for this evalua-
tion program.
2. Work for next period
During the coming month we will examine the spatial filtering capabilities
of the enlarger.
3. Visits to the Contractor
None
Approved For Release 2002/07/10 : CIA-RDP78BO4747AO02900030012-5
 Approved Fo - 40002900030012-5
4. Changes in Personnel
5. Progress of Work
As of this reporting date, approximately 45% of the contract funds have
been expended and 55% of the work program has been completed.
Approved For Release 2002/07/10 : CIA-RDP78BO4747AO02900030012-5
 Approved For,(elease 2002/07/10 : CIA-RDP78B0474(A002900030012-5
Approved For Release 2002/07/10 : CIA-RDP78BO4747AO02900030012-5
 Approved For(elease 2002/07/10 : CIA-RDP78B0474(A002900030012-5
Approved For Release 2002/07/10 : CIA-RDP78BO4747AO02900030012-5