🚀 go-pugleaf

In article <1992Jul23.190402.8618@fs7.ece.cmu.edu> schaefer@young.ece.cmu.edu  
(Roland Schaefer) writes:
> 
> I'm looking for some chart or data that will describe what
> the various spatial frequencies on the AF Resolution Chart
> are.  The chart just has various bars in groupings

The "USAF 1951 resolving power target" is defined by Military Standard 150A.   
An element consists of two target patterns of three lines each, at right angles  
to each other.  The width of a line equals the width of a space, and the line  
length is five times its width.  The change widths is an a geometric  
progression based on the sixth root of two, so that the number of lines per  
millimeter (say) doubles with every sixth target element.  And six elements are  
called a group.

For the 1/4 to 228 lines/mm target:

                Number of lines per millimeter:

                        Group Number

Element  -2   -1   0    1    2    3    4    5    6    7    8
Number  
1      0.250 0.500 1.00 2.00 4.00 8.00 16.0 32.0 64.0 128 256
2      0.280 0.561 1.12 2.24 4.49 8.98 18.0 36.0 74.8 144 287
3      0.315 0.630 1.26 2.52 5.04 10.1 20.2 40.3 80.6 161 323
4      0.353 0.707 1.41 2.83 5.66 11.3 22.6 45.3 90.5 181 362
5      0.397 0.793 1.59 3.17 6.35 12.7 25.4 50.8 102  203 406
6      0.445 0.891 1.78 3.56 7.13 14.3 28.5 57.0 114  228 456

Besides the Mil Std doc, this information is in the "usual handbooks".  I  
copied it from Book 3 of the 38th International Edition 1992 of "The Photonics  
Design & Applications Handbook", pg. H-30.  I have found this handbook to be  
filled with timely, as well as classic, information, and recommend it with  
enthusiasm.  (As an individual, not as a government employee.)

Regards,
Henning Leidecker