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IMAGE QUALITY CRITERIA FOR AERIAL SURVEY LENSES 
  
H. Tiziani 
1. Introduction 
The technique for measuring the modulation transfer function 
(MTF) is well established. Different national and international 
organisations (DIN, ISO, NATO and ISP) have endeavoured to 
establish a basis for assessing image quality. Although phase 
measurement is particularly important for new designs, its 
evaluation and interpretation require further study and are 
outside the scope of the present paper. 
The optical designer requires a lot of data such as OTF/MTF 
curves. The user, however, would prefer simplified MTF data 
for evaluating image quality or for locating the plane of 
best average definition. An approach to the development of 
suitable criteria based on reduced MTF data is here described. 
An objective marking procedure to rank evaluation systems by 
"quality numbers" according to their performance would be 
desirable. Before an appropriate evaluation system can be 
introduced, a number of interlaboratory comparisons will be 
necessary. One such evaluation system is described here. 
2. Image quality criteria 
Image quality criteria are different for microscopes, amateur 
cameras, magnifying or aerial Survey lenses, and therefore 
need to be adapted to the practical applications of the par- 
ticular optical system (14). This paper is concerned with image 
evaluation in aerial photography, where the requirements are: 
small or constant known distortion 
good image quality over the whole field 
longitudinal and transverse colour correction 
relative high aperture 
nearly equal intensity distribution over the whole image 
wide-band spectral transmission 
(a