ISO 9335:2025
(Main)Optics and photonics — Optical transfer function — Principles and procedures of measurement
Optics and photonics — Optical transfer function — Principles and procedures of measurement
This document gives general guidance for the construction and use of equipment for measurement of the optical transfer function (OTF) of imaging systems. This document specifies important factors that can influence the measurement of the OTF and gives general rules for equipment performance requirements and environmental controls. It specifies important precautions that should be taken to ensure accurate measurements and correction factors to be applied to the collected data. The OTF measuring equipment described in this document is restricted to that which analyses the radiation distribution in the image plane of the optical imaging system under test. Interferometer-based instruments are outside the scope of this document.
Optique et photonique — Fonction de transfert optique — Principes et procédures de mesure
L'ISO 9335:2012 fournit des lignes directrices concernant la construction et l'utilisation d'équipements pour mesurer la fonction de transfert optique (OTF) de systèmes de formation d'image. L'ISO 9335:2012 spécifie les facteurs importants pouvant influencer le mesurage de I'OTF, et donne des règles générales concernant les exigences de performance de l'équipement et les conditions d'environnement. Elle spécifie les précautions majeures à prendre pour assurer l'exactitude des mesurages et indique les facteurs de correction à appliquer éventuellement aux données recueillies.
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Standards Content (Sample)
International
Standard
ISO 9335
Third edition
Optics and photonics — Optical
2025-02
transfer function — Principles and
procedures of measurement
Optique et photonique — Fonction de transfert optique —
Principes et procédures de mesure
Reference number
© ISO 2025
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Contents Page
Foreword .v
Introduction .vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Measuring equipment and environment . 1
4.1 General aspects .1
4.1.1 Measuring conditions .1
4.1.2 Uncertainty of measurement .1
4.2 Environment .2
4.2.1 General .2
4.2.2 Temperature and humidity control .2
4.2.3 Vibration .2
4.2.4 Electromagnetic disturbances .2
4.3 Measuring equipment .2
4.3.1 Optical mounts .2
4.3.2 Defocusing tolerance .3
4.3.3 Provision of measuring scales .3
4.4 System components .3
4.4.1 General .3
4.4.2 Optical benches . .3
4.4.3 Test target unit .4
4.4.4 Mounting of the test specimen .9
4.4.5 Image evaluation system .9
4.4.6 Auxiliary imaging systems .10
5 Measurement procedures .10
5.1 General .10
5.2 Setting the measuring conditions .10
5.2.1 General .10
5.2.2 Environmental conditions .10
5.2.3 Spectral characteristics .11
5.2.4 Angular distribution and aperture considerations .11
5.2.5 Image scale and magnification .11
5.2.6 Focusing .11
5.3 Additional considerations of measurement. 12
5.3.1 General . 12
5.3.2 Linear range of test specimen . 12
5.3.3 Isoplanatic region . 12
5.3.4 Fixed pattern noise . 12
5.3.5 Analysed area . 12
5.3.6 Background radiation . 12
5.3.7 Veiling glare . 13
5.3.8 Parallelism of image and analysing element . 13
5.3.9 Signal-to-noise ratio . 13
5.4 Particular measuring conditions .14
5.4.1 Azimuths.14
5.4.2 Selection of image heights or field angles .14
5.4.3 Reference angles of the test specimen .14
6 Corrections to measured data . 14
6.1 Normalization.14
6.2 Correction of the frequency scale .14
6.3 Correction of the measured modulation . 15
6.4 Auxiliary imaging systems . 15
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7 Presentation of OTF data .15
7.1 General . 15
7.2 Statement of identification and measuring conditions . 15
7.3 Graphical presentation of OTF data .16
7.4 Numerical presentation .17
8 Uncertainty checks . 17
Annex A (informative) Examples of the presentation of OTF data . 19
Bibliography .24
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Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
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with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents I
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