DIN ISO 9334:2015-12

The optical transfer function (OTF) is an important aid to objective evaluation of the image-forming capability of optical, electro-optical and other imaging systems. To allow comparison of optical transfer function measurements achieved using different measuring principles and instruments, or obtained from measuring instruments in different laboratories, it is necessary to ensure equivalence of measurement parameters such as focus setting and spatial frequency range. For this reason, an agreed terminology shall be defined so that the measurement parameters called upon in a standard may be understood by all users. This standard contains the introduction and a set of definitions upon which optical transfer function theory is built and indicates, where pertinent, the mathematical relationships between those terms. It also contains a list of basic relationships of the optical transfer function to other image-describing parameters and a summary of concepts and symbols which are useful in optical transfer function work. The terms and parameters defined in this standard apply to all measurements of the optical transfer function for optical, electro-optical and other imaging systems. To summarize, this standard describes the optical transfer function as a tool which can be applied within well-defined limits to a large class of imaging systems in order to assess their image-forming capabilities. The committee responsible for this standard is NA 027-01-02-01 AK "Messverfahren für die Optik" ("General optical test methods") at DIN.