(b) 
- 17 - 
we have no easy intuitive way of 
translating frequency plots into 
image quality. 
In general, therefore, ways must be sought for supp 
lementing MTF’s with descriptions of image quality by methods 
that take account of the physical qualities of the emulsion 
and the properties of human vision. For the time being, 
empirical measurements involving formal targets, such as 
resolving power, will continue to be useful. 
11. Recommendations 
» 
1. Since the camera lens is the fundamental 
component, and since the successful app 
lication of the OTF to aerial photography 
in general depends on reliable measure 
ments on camera lenses, the Working Party 
considers the first task to be the impro 
vement of accuracy in OTF measuring tech 
niques. 
2. The Working Party requests the co-operat 
ion of qualified laboratories in working 
towards the improvement of accuracy for 
lens OTF measurements including the exact 
specification of measuring coditions, 
estimates of probable errors, choice of 
standard lenses for exchange between lab 
oratories, and generally in devising approp 
riate qualification tests for apparatus. 
3» The Working Party does not recommend any 
particular method for measuring lens OTF 
in preference to other methods. Whatever 
method may be used, evidence of its accur 
acy should be presented. 
References 
References (1) through (6) are concerned with interp 
retation of MTF's. 
(1) Brock, G. C., Photogrammetria, XVI, No. 3 1959/1960 
Special Congress Number B. 
(2) Study of Image Evaluation Techniques, Interim Engin 
eering Report No. 3» Itek Corporation, (Contract 
AF 33 (657) - 9158) 
(3) Scott, Frank, Photographic Science and Engineering, 
10, No. 1, Jan/Feb 1966