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SUMMARY REPORT OF THE IMAGE QUALITY
WORKING GROUP (WG-1), 1976-78
Dy
R. Welch, P. N. Slater,
H. Tiziani, and J. C. Trinder
The Image Quality Working Group was established in early 1977,
subsequent to the Helsinki Congress, and expands the activities of its
predecessor, the Optical and Modulation Transfer Function (OTF/MTF)
Working Group. The primary objective of the Image Quality Working Group
is to assess measures of system performance and image quality and relate
these to the interpretability and measurability of image detail. Methods
of OTF/MTF measurement and analysis are included within the interests
of the group.
Members of the Image Quality Working Group were selected to investi-
gate a range of subjects of interest to the ISP, including: 1) OTF/MTF
evaluation procedures and their applications in testing photogrammetric
lenses and camera systems (Dr. Hans Tiziani, Wild-Heerbrugg, Heerbrugg,
Switzerland and the Institute of Applied Optics, Stuttgart, FRG);
2) optical and electro-optical sensor system characteristics and
performance (Dr. R. Welch, University of Georgia and Dr. P. N. Slater,
University of Arizona, USA); and 3) measures of image quality and their
relation to the measurability and interpretability of image detail
(Dr. J. C. Trinder, University of New South Wales, Australia). A brief
summary of the activities of the group in each of these subject areas
is presented in the following paragraphs.
OTF/MTF
Techniques to measure the MTF of photogrammetric camera lenses are
now well-established in countries such as Great Britain, Germany,
Switzerland, and Japan, and it is generally agreed that good correlation |
can be obtained between measurements conducted at different laboratories. |
Consequently, in addition to classical area-weighted average resolution |
(AWAR) tests, MTF's offer an objective means of determining "quality |
numbers" suitable for ranking and comparing optical systems. One
approach suggested as a substitute for the conventional procedures is to
determine an AWAR value from the intersections of measured lens MTF's
at different field positions with the threshold modulation (TM) curve of i
the test film. Good agreement between AWAR's determined by conventional
and intersection techniques has been experienced in laboratory tests. b
