1、December 2015 English price group 14No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 17.180.01!%I“2385693www.din.deD
2、IN ISO 9335Optics and photonics Optical transfer function Principles and procedures of measurement (ISO 9335:2012),English translation of DIN ISO 9335:2015-12Optik und Photonik Optische bertragungsfunktion Prinzipien und Messverfahren (ISO 9335:2012),Englische bersetzung von DIN ISO 9335:2015-12Opti
3、que et photonique Fonction de transfert optique Principes et procdures de mesure (ISO 9335:2012),Traduction anglaise de DIN ISO 9335:2015-12SupersedesDIN ISO 9335:2008-04www.beuth.deDocument comprises 29 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be
4、considered authoritative.11.15 A comma is used as the decimal marker. Contents PageNational foreword 3Introduction 51 Scope 62 Normative references . 63 Terms and definitions . 64 Measuring equipment and environment . 64.1 General aspects . 64.2 Environment . 74.3 Measuring equipment . 74.4 System c
5、omponents . 85 Measurement procedures .155.1 General .155.2 Setting the measuring conditions .155.3 Additional considerations of measurement . 165.4 Particular measuring conditions .186 Corrections to measured data .196.1 Normalization .196.2 Correction of the frequency scale 196.3 Correction of the
6、 measured modulation .196.4 Auxiliary imaging systems .207 Presentation of OTF data 207.1 General .207.2 Statement of identification and measuring conditions .207.3 Graphical presentation of OTF data .217.4 Numerical presentation .228 Accuracy checks .22Annex A (informative) Examples of the presenta
7、tion of OTF data 24Bibliography .29DIN ISO 9335:2015-12 2National Annex NA (informative) Bibliography. 4National foreword This document (ISO 9335:2012) has been prepared by Technical Committee ISO/TC 172/SC 1 “Fundamental standards”, (Secretariat: DIN, Germany). The responsible German body involved
8、in its preparation was DIN-Normenausschuss Feinmechanik und Optik (DIN Standards Committee Optics and Precision Mechanics), Working Committee NA 027-01-02 AA Grundnormen der Optik. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. D
9、IN shall not be held responsible for identifying any or all such patent rights. The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 9334 DIN ISO 9334 ISO 9336-3 DIN ISO 9336-3 ISO 11421 DIN ISO 11421 Amendments This standard differs from DI
10、N ISO 9335:2008-04 as follows: a) normative references have been updated; b) the Figures have been editorially revised; c) the Bibliography has been updated; d) the text of the revised version ISO 9335:2012 has been adopted in its entirety. Previous editions DIN 58185-2: 1976-03 DIN 58185-3: 1978-08
11、 DIN 58185-4: 1978-12 DIN ISO 9335: 2002-07, 2008-04 DIN ISO 9335:2015-12 3 National Annex NA (informative) Bibliography DIN ISO 9334, Optics and photonics Optical transfer function Definitions and mathematical relationships DIN ISO 9336-3, Optics and optical instruments Optical transfer function Ap
12、plication Part 3: Telescopes DIN ISO 11421, Optics and optical instruments Accuracy of optical transfer function (OTF) measurements DIN ISO 9335:2015-12 4 IntroductionThe optical transfer function is an important aid to objective evaluation of the image-forming capability of optical, electro-optical
13、 and photographic systems.In order that optical transfer function measurements achieved using different measuring principles or obtained from measuring instruments in different laboratories can be compared, it is necessary to ensure equivalence of measurement parameters such as focus setting and spa
14、tial frequency range. For this reason, an agreed terminology has been defined in order for the measurement parameters used in this International Standard to be understood by all users. This International Standard gives guidance for the construction and operation of equipment for optical transfer fun
15、ction measurement.The specifications in this International Standard form the basic requirements of measurement instrumentation and procedures for guaranteeing a defined accuracy of measurement of the optical transfer function.Optics and photonics Optical transfer function Principles and procedures o
16、f measurementDIN ISO 9335:2015-12 5 1 ScopeThis International Standard gives general guidance for the construction and use of equipment for measurement of the optical transfer function (OTF) of imaging systems.This International Standard specifies important factors that can influence the measurement
17、 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 Int
18、ernational Standard 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 International Standard.2 Normative referencesThe following referenced documents are indispen
19、sable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 9334, Optics and photonics Optical transfer function Definitions and mathematical relationshi
20、ps3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 9334 apply.4 Measuring equipment and environment4.1 General aspects4.1.1 Measuring conditionsAny measured OTF depends on the imaging state (I-state) of the imaging system. Thus, before making measureme
21、nts, those parameters which form the I-state of the system shall be identified and the degree to which the I-state depends on those parameters determined. The complete set of parameters that form the I-state shall be set to fixed values. The fixed values represent a particular I-state and are called
22、 the measuring conditions.4.1.2 Accuracy of measurementThe measuring equipment, and the environment in which it is used, shall allow the prescribed measuring conditions to be set and maintained to a precision which is consistent with the required accuracy of measurement (see ISO 11421, which describ
23、es the various parameters which have an impact on the accuracy of measurement). The accuracy of an OTF measurement may be considered as the combination of measurement uncertainties arising from the many separate parameters in the I-state. When a required accuracy of OTF measurement is stated, it sha
24、ll be apportioned among the known contributing parameters such that a tolerance can be set for each parameter of the I-state. Thus, an overall requirement to an accuracy of measurement of 0,05 of the modulation transfer function (MTF) might require, among other factors, a temperature stability of th
25、e measuring equipment of 1 C and focal plane setting to 5 m. The discussion of instrumental and environmental settings DIN ISO 9335:2015-12 6 in the following subclauses relates to tolerances apportioned from the required OTF measurement accuracy in this manner.4.2 Environment4.2.1 GeneralThe ambien
26、t conditions of the OTF equipment shall be kept sufficiently free from influences that can lead to climatic, mechanical or electromagnetic disturbances. The measuring equipment and the atmosphere in the measuring room shall be kept free from dust, moisture and smoke. All optical surfaces shall be pr
27、otected from the incidence of scratches and finger prints.4.2.2 Temperature and humidity controlThe temperature shall be kept constant within a stated tolerance and at a suitable value. Humidity shall also be kept within acceptable limits. Both temperature and humidity shall be recorded. Air turbule
28、nce and stratification may affect the measurement and shall be minimized through the use of shielding.4.2.3 VibrationVibration shall be kept to a minimum and the use of basement space is recommended if vibration, caused for example by machinery, cannot otherwise be avoided. The degree of vibration i
29、solation for a given measuring accuracy depends on the characteristics of the vibration, the measuring method, and the spatial frequency range. If the method consists of measuring the line spread function, a suitable tolerance might be that the movement of the image and the analyser caused by vibrat
30、ions should not exceed, for example, 1/20 of the width at half the maximum intensity of the test slit image.4.2.4 Electromagnetic disturbancesFor some systems, it can be necessary to monitor power supply vibrations and keep these to a tolerable minimum. The influence of external electromagnetic fiel
31、ds and the level of ambient light shall be reduced until they do not affect the measured OTF significantly.4.3 Measuring equipment4.3.1 Optical mountsThe basis of any measuring equipment shall be a sturdy optical bench or plate, to which mountings for the test target unit, test specimen, image analy
32、ser and other auxiliary units can be attached and brought into position, with respect to each other, to the required accuracy.Depending on the imaging systems to be tested, different requirements can arise regarding the linearity of adjustments and/or the parallelism of equipment slideways. Deviatio
33、ns from ideal linearity and parallelism requirements shall not cause a greater change of the measured MTF than 1/3 of the permitted or specified measurement accuracy.4.3.2 Defocusing toleranceFor photographic lenses, the defocusing effects caused by bench misalignment result in errors in the measure
34、d MTF which increase with rising spatial frequency or with decreasing f-number and reduced wavefront aberration. Table 1 gives the defocusing tolerances of a diffraction-limited lens with circular pupil and incoherent illumination that leads to a 0,05 MTF change. The wavelength of the light is assum
35、ed to be 500 nm.DIN ISO 9335:2015-12 7 Table 1 Defocusing tolerancesDimensions in micrometresf-numberDefocusing tolerance for spatial frequencymm11 5 10 20 50 1001 45 9 4,5 2,3 1,0 0,51,4 62 12,5 6,3 3,2 1,4 0,82 89 18 9 4,7 2,0 1,14 180 36,5 18,8 9,8 4,6 38 360 74 39 21,5 12 12,216 720 157 86 54 49
36、 468NOTE For a change of 0,10 in MTF, defocusing tolerances are twice those shown in this table.4.3.3 Provision of measuring scalesThe measuring equipment shall provide adequate means for determining the positions of test target, system or device under test (test specimen), image analyser and auxili
37、ary systems. These include scales, spindles and dial gauges. Furthermore, means shall be provided to monitor, set or determine all other parameters that form the I-state of the specimen.4.4 System components4.4.1 GeneralThe following subclauses give details concerning the measuring arrangement and i
38、ts basic elements including the test target unit, test specimen, image analyser and auxiliary imaging systems.4.4.2 Optical benches4.4.2.1 GeneralSeveral arrangements of the measuring equipment are possible, but those in 4.4.2.2 to 4.4.2.5 are recommended.4.4.2.2 Object and image at finite conjugate
39、sFor tests in which object and image are at finite distances from the test specimen, the configurations shown in Figure 1 or 2 shall be used. In these arrangements, two of the three basic units (test specimen, test target unit and image analyser) are moved along slideways parallel to one another and
40、 perpendicular to the reference axis. Usually, the test specimen is fixed and the other two units moved as shown in Figures 1 and 2.When electro-optical components such as image intensifiers are to be tested, auxiliary imaging systems are used to produce an image of the test pattern at the input of
41、the test specimen. The image at the output of the test specimen is then relayed to the image analyser. The corresponding arrangement is shown in Figure 2.4.4.2.3 Nominal infinite object conjugateFor tests in which the object conjugate is infinite (i.e. the test target is at the principal focus of a
42、collimator), arrangements similar to that shown in Figure 3 shall be used. When off-axis measurements are to be made, the collimator may be rotated by an angle about an axis passing through the entrance pupil of the test specimen and perpendicular to the reference axis (see Figure 3).Alternatively,
43、the collimator may be fixed and the test specimen and image analyser rotated together about the entrance pupil. In this case, the mounting fixture for the test specimen and the image analyser slideway DIN ISO 9335:2015-12 8 are both rigidly fixed to a rotating baseplate (this arrangement is conseque
44、ntly often referred to as the “rotary table” type).4.4.2.4 Nominal infinite image conjugateThe same arrangement as described in 4.4.2.3 (see Figure 3) shall be used, with the image analyser and test target unit interchanged.4.4.2.5 Object and image at nominal infinite conjugatesFor systems which are
45、 tested with both the object and image at infinite conjugates, arrangements similar to those shown in Figure 4 shall be used. When off-axis measurements are to be made, the object side collimator with the test target unit should be rotated by an angle about an axis passing through the entrance pupil
46、 and perpendicular to the reference axis of the test specimen. The image side decollimator, together with the image analyser, shall be rotated by an angle about an axis passing through the exit pupil and perpendicular to the reference axis and shall be refocused according to the test criteria.4.4.3
47、Test target unit4.4.3.1 GeneralThe test target unit shall consist of a source of radiation and a test target.4.4.3.2 Test targetDepending on the characteristics of the test specimen, several different types of test target may be used. Circular apertures, slits, edges, gratings and self-luminous test targets such as incandescent wires are commonly used. The spatial frequency spectrum of the test target used for the OTF measurement shall be known with an accuracy that is determined by the required measuring accuracy. The actual frequency spectrum of the test target usually differs from its i
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