1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 14490-8:2011Optics and optical instruments Test methods for telescopicsystemsPart 8: Test methods for night-vision devicesBS ISO 14490-8:2011 BRITISH STANDARDNational fore
2、wordThis British Standard is the UK implementation of ISO 14490-8:2011.The UK participation in its preparation was entrusted to TechnicalCommittee CPW/172/4, Optics and Photonics - Telescopic Systems.A list of organizations represented on this committee can beobtained on request to its secretary.Thi
3、s publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 66386 4ICS 37.020Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the
4、 authority of theStandards Policy and Strategy Committee on 30 November 2011.Amendments issued since publicationDate Text affectedBS ISO 14490-8:2011Optics and optical instruments Test methods for telescopic systems Part 8:Test methods for night-vision devicesOptique et instruments doptique Mthodes
5、dessai pour systmes tlscopiques Partie 8: Mthodes dessai pour dispositifs de vision de nuit ISO 2011Reference numberISO 14490-8:2011(E)First edition2011-09-15ISO14490-8INTERNATIONAL STANDARDBS ISO 14490-8:2011ISO 14490-8:2011(E)COPYRIGHT PROTECTED DOCUMENT ISO 2011All rights reserved. Unless otherwi
6、se specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright of
7、ficeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in Switzerlandii ISO 2011 All rights reservedBS ISO 14490-8:2011ISO 14490-8:2011(E)Contents PageForeword .v1 Scope 12 Normative references .13 General requirements for the
8、test conditions and preparation of tests .14 Test method for measuring magnification and difference in magnification .24.1 General .24.2 Requirements for the test arrangements and their principal parts .34.3 Sequence of measurements .54.4 Assessment of results .55 Test method for measuring night-vis
9、ion device gain 65.1 General .65.2 Requirements for the test arrangement and principal parts .65.3 Sequence of measurements .75.4 Assessment of results .76 Test method for measuring the angular field of view in object space 76.1 General .76.2 Requirements for the test arrangement and principal parts
10、 .76.3 Sequence of measurements .86.4 Assessment of results .87 Test method for measuring exit pupil diameter and eye relief 97.1 General .97.2 Requirements for the test arrangement and its principal parts .97.3 Sequence of measurements .108 Test method for measuring the error of zero-position of th
11、e dioptre scale 108.1 General .108.2 Requirements for the test arrangement and its principal parts .108.3 Sequence of measurements .118.4 Assessment of results .119 Test method for measuring the angle of image rotation around the optical axis relative to the object and the difference of image rotati
12、on angles .129.1 General .129.2 Requirements of the test arrangement and its principal parts .129.3 Sequence of measurements .139.4 Assessment of results .1310 Test method for measuring non-parallelism of the axes of bundles of rays emerging from the eyepieces of the night-vision device .1310.1 Gene
13、ral .1310.2 Requirements of the test arrangement and its principal parts .1310.3 Sequence of measurements .1510.4 Assessment of results .1511 Test method for measuring the limit of resolution .1511.1 General .1511.2 Requirements for the test arrangement and its principal parts .1511.3 Sequence of me
14、asurements .1611.4 Assessment of results .1612 Test method for measuring working resolution and for determining range of vision .1612.1 General .1612.2 Requirements for the test arrangement and its principal parts .1712.3 Sequence of measurements .17 ISO 2011 All rights reserved iiiBS ISO 14490-8:20
15、11ISO 14490-8:2011(E)12.4 Assessment of results .1813 Test method for measuring the close distance of observation 1913.1 General .1913.2 Requirements for the test arrangement and its principal parts .1913.3 Sequence of measurements .2013.4 Assessment of results .2014 Test method for imperfections in
16、 the field of view .2014.1 General .2014.2 Requirements for the test arrangement and its principal parts .2014.3 Sequence of measurements .2114.4 Assessment of results .2215 Test method for measuring the continuous work time of a night-vision device 2215.1 General .2215.2 Requirements for the test a
17、rrangement and its principal parts .2215.3 Sequence of measurements .2215.4 Assessment of results .22Bibliography .23iv ISO 2011 All rights reservedBS ISO 14490-8:2011ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member b
18、odies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental a
19、nd non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.International Standards are drafted in accordance with the rules given in the ISO/IEC Directives,
20、 Part 2.The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies cast
21、ing a vote.Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights.ISO 14490-8 was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommit
22、tee SC 4, Telescopic systems.ISO 14490 consists of the following parts, under the general title Optics and optical instruments Test methods for telescopic systems: Part 1: Test methods for basic characteristics Part 2: Test methods for binocular systems Part 3: Test methods for telescopic sights Par
23、t 4: Test methods for astronomical telescopes Part 5: Test methods for transmittance Part 6: Test methods for veiling glare index Part 7: Test methods for limit of resolution Part 8: Test methods for night-vision devicesISO 14490-8:2011(E) ISO 2011 All rights reserved vBS ISO 14490-8:2011BS ISO 1449
24、0-8:2011INTERNATIONAL STANDARD ISO 14490-8:2011(E)Optics and optical instruments Test methods for telescopic systems Part 8:Test methods for night-vision devices1 ScopeThis International Standard describes the test methods for determining the performance of night-vision devices as specified in ISO 2
25、1094.2 Normative referencesThe following referenced documents are indispensable 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 5725-1, Accuracy (t
26、rueness and precision) of measurement methods and results Part 1: General principles and definitionsISO 11664-2, Colorimetry Part 2: CIE standard illuminantsISO 14490-1, Optics and optical instruments Test methods for telescopic systems Part 1: Test methods for basic characteristicsISO 14490-7, Opti
27、cs and optical instruments Test methods for telescopic systems Part 7: Test methods for limit of resolutionISO 21094, Optics and photonics Telescopic systems Specifications for night vision devices3 General requirements for the test conditions and preparation of testsMeasurements shall be carried ou
28、t under the normal conditions of the work area, namely: air temperature: (20,0 5,0) C; relative humidity of the air: 40 % to 60 %.During measurements, the temperature shall not vary by more than 2 C and the relative humidity shall not vary by more than 4 %.The measurements should be carried out in c
29、onditions in which the test specimen is protected from stray light and electrical and strong magnetic fields.The recommended illuminance in the test room is 0,01 lx to 0,04 lx.Measurements of the basic characteristics of night-vision devices shall be carried out with the aid of a dedicated power sup
30、ply.The use of an external power supply is acceptable subject to its voltage not departing from the nominal voltage of the dedicated power supply by more than 0,1 V.The testing of instruments equipped with a source of radiation shall be carried out while the source is switched off. ISO 2011 All righ
31、ts reserved 1BS ISO 14490-8:2011The source of radiation used in collimators and other instruments for measuring the characteristics of production prototypes of night-vision devices shall be incandescent lamps which have a filament colour temperature, Tc, of (2 856 50) K, unless otherwise stated. The
32、 instability of the voltage on incandescent lamps, at the time of measurement, shall not exceed 0,3 %.It is important that the spectral characteristics of the source of radiation cover the full range of spectral sensitivity of the image intensifier. The transmission spectrum of filters placed in col
33、limators or in front of a night-vision device shall correspond to the sensitivity spectral region of the test specimen.When measuring the characteristics of production samples, the use of incandescent lamps, where the filament colour temperature, Tc, is different from the one specified above, is acc
34、eptable.The objectives of collimators used in test arrangements may be lens, mirror or catadioptric systems.Integrating spheres may be used for uniform illumination of scales and reticles in collimators.During all measurements of the characteristics of night-vision devices, the luminance of the imag
35、e intensifier screen shall be the optimum for the observer.In the assessment of results (see 4.4, 5.4, 6.4, 7.4, 8.4, 9.4, 10.4, 11.4, 13.4 and 14.4), repeatability shall be stated in accordance with ISO 5725-1. The assessment of the correctness of the average value obtained, i.e. the assessment of
36、the systematic error, shall be carried out either analytically or by comparison of the measurement results obtained in different test laboratories.4 Test method for measuring magnification and difference in magnification4.1 GeneralThe measurement of magnification is based on the measurement of the i
37、mage size of an object within the field of view of the night-vision device.The magnification, , is calculated in accordance with the following equation: =tantanww(1)where w and w are the angles between the conjugate rays and the optical axis in object space and in image space respectively.For night-
38、vision devices with variable magnification, shall be measured for the maximum and minimum magnifications.Depending on the value of magnification and the size of the field of view of the night-vision device, the measurements of shall be carried out in accordance with the arrangements shown in Figure
39、1 or Figure 2.The diameter of the collimator lens used in these arrangements shall exceed by 15 % to 20 % the lens diameter of the test specimen.The diameter of the telescope objective lens used shall exceed by 15 % to 20 % the diameter of the pencil of light that emerges from the test specimen.ISO
40、14490-8:2011(E)2 ISO 2011 All rights reservedBS ISO 14490-8:20114.2 Requirements for the test arrangements and their principal parts4.2.1 Requirements for the test arrangement shown in Figure 1Key1 source of radiation 7 collimator lens2 condenser 8 test specimen3 filter 9 telescope objective lens4 d
41、iffusing plate 10 telescope read-out device5 collimator scale with cross-lines a11 reticle6 opaque diaphragm with aperture 12 telescope eyepieceaFor this method, a scale without cross-lines may be used. When testing as specified in other test methods, the use of a cross-line can be indispensable. Fo
42、r the sake of unification, it is recommended that a scale with cross-lines be used in all test arrangements.Figure 1 Arrangement for measurement of the magnification and difference in magnification of night-vision devices with fields of view up to 12 and magnifications up to 1,5The linear size of th
43、e collimator scale shall be such that the size of the image of the scale at the image intensifier screen of the night-vision device would cover 1/5 to 2/5 of the diameter of image intensifier screen.For the scale (5), the line widths and the spaces between them shall have dimensions that are at leas
44、t 2 times greater than the limit of resolution of the test specimen, so that they can be clearly resolved.The marginal part of the scale (5) shall be opaque; this is achieved by means of a diaphragm (6).The range of the scale of the telescope read-out device (10) (see Figure 1) shall be at least 25
45、mm with a read-out error of no more than 0,05 mm.Aberrations of the optical systems of the collimator and telescope shall be within the limits that allow for the specified precision of measurements.NOTE The requirements for the aberrations of the optical systems might be less severe if corrections f
46、or the real angular sizes of the scale divisions and of the telescope scale movement read-out mechanism are applied to the measurement results.It is important that the spectral characteristics of the source of radiation cover the long-wavelength cut-off of the image intensifier.It is recommended tha
47、t the support beneath the test specimen allows for its movement normal to the collimator axis, in order to enable successive measurements to be made of the magnification in each channel of the night-vision device.ISO 14490-8:2011(E) ISO 2011 All rights reserved 3BS ISO 14490-8:20114.2.2 Requirements
48、 for the test arrangement shown in Figure 2Key1 source of radiation 8 telescope objective lens2 condenser 9 reticle with cross-line3 filter 10 telescope eyepiece4 diffusing plate 11 angle-measuring device5 scale with cross-lines 12 angle-measuring device6 collimator lens 13 fixed indexes7 test speci
49、men 14 fixed indexesFigure 2 Arrangement for measurement of the magnification and difference in magnification of night-vision devices with any field of view and any magnificationThe focal plane of the collimator lens shall bear a scale with cross-lines, where the line width shall exceed the limit of resolution of the night-vision device under test at least by 2 times.The field of view of the collimator and that of the telescope may not exceed 1.The focal plane of
