1、April 2008DEUTSCHE NORM English price group 11No part of this standard 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 37.020!$Mj“1427194www.di
2、n.deDDIN ISO 15795Optics and photonics Quality evaluation of optical systems Assessing the image quality degradation due to chromatic aberrations(ISO 15795:2002+Cor. 1:2007)English version of DIN ISO 15795:2008-04Optik und Photonik Beurteilung der Qualitt optischer Systeme Bestimmung der Beeintrchti
3、gung der Bildqualitt durch chromatische Aberrationen(ISO 15795:2002+Cor. 1:2007)Englische Fassung DIN ISO 15795:2008-04SupersedesDIN ISO 15795:2006-03www.beuth.deDocument comprises 20 pages2 Contents Page National foreword .3 National Annex NA (informative) Bibliography 3 Introduction.4 1 Scope 5 2
4、Normative references 5 3 Symbols and units.5 4 Terms and definitions, principle and mathematical relationships .6 4.1 General6 4.2 Wavelengths and spectral distributions .6 4.2.1 Quasi-monochromatic measurement6 4.2.2 4.3 Reference wavelength and weighted spectral reference distribution .7 4.4 Measu
5、rement plane .7 4.5 Image heights and local image field coordinates 7 4.6 Lateral chromatic aberration 8 4.7 Weighted lateral chromatic aberration8 4.8 Form and extent of the edge spread function (ESF)8 4.8.1 General8 4.8.2 Edge widths9 4.8.3 Chromatic edge widths 11 4.9 Longitudinal chromatic aberr
6、ation . 11 5 Classes of applications 12 6 Measurement procedures 12 6.1 Brief description of the procedures 12 6.1.1 Measurement of lateral chromatic aberrations and edge width in a fixed measurement plane. 12 6.1.2 Measurement of longitudinal chromatic aberrations 13 6.2 Description of measurement
7、equipment 13 6.2.1 General requirements. 13 6.2.2 Infinite object distance, finite image distance.13 6.2.3 Finite object distance, finite image distance .14 6.3 Particular measurement conditions . 14 6.3.1 Azimuths, . 14 6.3.2 Orientation, , of the optical system to be tested . 15 6.3.3 Selection of
8、 image heights 15 7 Presentation of the results 15 7.1 Presentation in the form of tables 15 7.2 Graphical presentation. 16 8 Test report . 16 Annex A (informative) Examples of the presentation of results . 17 Bibliography. 20 Measurement with finite spectral bandwidth .7 DIN ISO 15795:2008-04 DIN I
9、SO 15795:2008-04 3 National foreword This standard has been prepared by Technical Committee ISO/TC 172 “Optics and photonics”, Subcommittee SC 1 “Fundamental standards” (Secretariat: DIN, Germany). The responsible German body involved in its preparation was the Normenausschuss Feinmechanik und Optik
10、 (Optics and Precision Mechanics Standards Committee). The DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 9039 DIN 58187; E DIN ISO 9039 ISO 9334 DIN ISO 9334 ISO 9335 DIN ISO 9335 ISO 11421 DIN ISO 11421 Amendments This standard differs f
11、rom DIN ISO 15795:2006-03 as follows: a) The first element of the title “Optics and optical instruments” has been replaced with “Optics and photonics”. b) Subclause 7.1 “Presentation in the form of tables” has been corrected and the National Footnote N1) has been deleted. c) Technical Corrigendum 1:
12、2007 to ISO 15795:2002 has been adopted. Previous editions DIN ISO 15795: 2005-09, 2006-03 National Annex NA (informative) Bibliography DIN 58187, Quality evaluation of optical systems Determination of radial distortion E DIN ISO 9039, Optics and photonics Quality evaluation of optical systems Deter
13、mination of distortion DIN ISO 9334, Optics and photonics Optical transfer function Definitions and mathematical relationships DIN ISO 9335, Optics and photonics Optical transfer function Principles and procedures of measurement DIN ISO 11421, Optics and optical instruments Accuracy of optical trans
14、fer function (OTF) measurement 4 Optics and photonics Quality evaluation of optical systems Assessing the image quality degradation due to chromatic aberrations Introduction Aberrations due to the variation of the refractive index with wavelength (dispersion) are usually termed “chromatic aberration
15、s”. Originally, this wording was based on the fact that, in the presence of these aberrations, the image of objects such as points, lines and edges, exhibit coloured fringes in addition to the variation of luminance. From this point of view, the concept of the point spread function (PSF) and the rel
16、ated optical transfer function (OTF), see ISO 9334, is basically a luminous (or more general radiative) transfer of optical information. There is only one signal regarding wavelength which is the result of the spectral transmission and sensitivity of the transmission chain, even if the latter is not
17、 identical to the relative luminous sensitivity of the human eye. Nowadays, the terms “colour” and, more specifically, “chroma” in the domain of physical science are well defined by colorimetry according to CIE Publication Nr. 15.2 (see reference 1 in the Bibliography) and are restricted to that reg
18、ion of the electromagnetic spectrum, which is accessible to the normal (trichromatic) human observer. However, when concerned with aberrations due to the dispersive behaviour of electromagnetic waves, it is necessary to take into account that the spectral region of the optical waveband is by far wid
19、er than the limits of sensitivity of the human eye. This region may extend from the UV to the medium IR. In such applications, the human visual process is not involved or, if so, only by means of certain translations of the information into the visual waveband. Nevertheless, the fact of variation of
20、 the form and position of the point or line spread function with wavelength or with some spectrally weighted wavebands is still given. To characterize this dispersive behaviour, one has not to deal with colorimetry, but should describe the position and extent of the spread function relative to that
21、of a certain reference wavelength or reference spectral weighting. In this sense, the present International Standard will not deal with colour sensations, but the term “chromatic aberrations” is used in a purely physical manner to describe the wavelength dependent properties of such aberrations. The
22、 variation of the spread function with wavelength in a given image plane of an optical system may be characterized by a lateral translation and additionally by a variation in form and width. The lateral translation of a typical coordinate point of the spread function will be called lateral chromatic
23、 aberration, whereas the form and extent can be characterized by two numbers derived from a weighting procedure over the spread function (edge width). The longitudinal chromatic aberration indicates the axial position of the best image plane for a certain wavelength or waveband with respect to a ref
24、erence plane and for a defined focusing (or image quality) criterion. DIN ISO 15795:2008-04 5 1 Scope This International Standard defines terms relating to chromatic aberrations and indicates the mathematical relationships between those terms. It also gives general guidance for the measurement of ch
25、romatic aberrations and is valid for optical imaging systems which are constructed to be of rotational symmetric imaging geometry. It is also valid for optoelectronic imaging systems. 2 Normative references The following normative documents contain provisions which, through reference in this text, c
26、onstitute provisions of this International Standard. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent
27、editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 9334:1995, Optics and optical instruments Optical transfer function
28、 Definitions and mathematical relationships ISO 9335:1995, Optics and optical instruments Optical transfer function Principles and procedures of measurement ISO 9039:1994, Optics and optical instruments Quality evaluation of optical systems Determination of distortion ISO 11421:1997, Optics and opti
29、cal instruments Accuracy of optical transfer function (OTF) measurement 3 Symbols and units Symbol Meaning Unit Specified in Measurement wavelength nm, m 4.2.1 rReference wavelength nm, m 4.3 W() Weighted spectral distribution dimensionless 4.2.2 WR() Weighted spectral reference distribution dimensi
30、onless 4.3 u() Local image field coordinate for measurement wavelength m 4.5 u(r) Local image field coordinate for reference wavelength m 4.5 u(W) Local image field coordinate for weighted spectral measurement distribution m 4.5 u(WR) Local image field coordinate for weighted spectral reference dist
31、ribution m 4.5 h(r), h(WR) Image height for reference wavelength or distribution mm 4.5 T() Lateral chromatic aberration m 4.6 T(W) Weighted lateral chromatic aberration m 4.7 DIN ISO 15795:2008-04 6 Symbol Meaning Unit Specified inL() Longitudinal chromatic aberration m 4.9 L(W) Weighted longitudin
32、al chromatic aberration m 4.9 LE Left edge width m 4.8.2 RE Right edge width m 4.8.2 EW Edge width m 4.8.2 z(), z(r) Position of best focus for wavelengths and rmm 4.9 z(W), z(R) Position of best focus for spectral weightings W() and WR() mm 4.9 pImage pupil field angle degree 3.8 of ISO 9039:1994 p
33、Object pupil field angle degree 3.7 of ISO 9039:1994 OTF(r) One-dimensional optical transfer function dimensionless 3.11 of ISO 9334:1995 MTF(r) One-dimensional modulation transfer function dimensionless 3.9 of ISO 9334:1995 PTF Phase transfer function degree, rad 3.10 of ISO 9334:1995 PSF Point spr
34、ead function mm23.5 of ISO 9334:1995 LSF Line spread function mm13.13 of ISO 9334:1995 ESF Edge spread function dimensionless 3.14 of ISO 9334:1995 Azimuth degree 4.21 of ISO 9334:1995 Reference angle degree 4.12 of ISO 9334:1995 Integration variable dimensionless 4.5 4 Terms and definitions, princi
35、ple and mathematical relationships 4.1 General For the purposes of this International Standard, the terms and definitions given in ISO 9334 and ISO 9335 apply. 4.2 Wavelengths and spectral distributions For the determination of chromatic aberrations, several wavelengths or spectral distributions sha
36、ll be given for which the aberrations are to be determined. 4.2.1 Quasi-monochromatic measurement In this case, the spectral bandwidth of the measurement radiation is small compared to the distance between neighbouring measurement wavelengths. The measurement wavelength under consideration is the me
37、an wavelength of that quasi-monochromatic radiation for which the chromatic aberrations are to be determined. DIN ISO 15795:2008-04 7 4.2.2 Measurement with finite spectral bandwidth The spectral bandwidth is specified by a spectral weighting function, W(). For the purpose of analytical calculations
38、, this shall be approximated by spectral area weighting with different discrete wavelengths. The measurements of chromatic aberrations shall always be carried out in the same manner, regardless of whether they are determined for discrete wavelengths or for certain wavebands. 4.3 Reference wavelength
39、 and weighted spectral reference distribution In the case of quasi-monochromatic radiation (see 4.2.1), the reference wavelength, r, is the wavelength to which the determination of the chromatic aberrations is related. In the case of finite spectral bandwidth (see 4.2.2), the reference spectral dist
40、ribution is the spectral weighting function, WR(), to which the determination of the chromatic aberrations is related. 4.4 Measurement plane The measurement plane is a plane perpendicular to the optical axis in which the measurement is carried out. It may be defined by geometric means, or with the h
41、elp of a suitably defined focusing criterion, which can be applied by measurement and shall be accessible for analytical calculations. 4.5 Image heights and local image field coordinates The image heights are defined by means of the line spread function (LSF). Figure 1 shows an example of (measured)
42、 line spread functions. For the definition of line spread function, see 3.13 of ISO 9334:1995. This definition is also valid for weighted spectral distribution, W(). Figure 1 Examples for quasi-monochromatic line spread functions The image height, h, is the position within the line spread function w
43、here the area fractions of the line spread function are equal. DIN ISO 15795:2008-04 8 Thus: 1LSF( )d LSF( )d2h + =(1) where is an integration variable. Local image field coordinates, u, are introduced by choosing the origin u = 0 at the reference image height, h(r), for the reference wavelength, r,
44、 or h( WR) for the weighted spectral reference distribution, WR(). 4.6 Lateral chromatic aberration The lateral chromatic aberration, T(), is defined as the radial variation in image height for the wavelength, , relative to the image height for the reference wavelength, r. This definition requires a
45、 numerical evaluation of the line spread function, as it is also necessary for the determination of the optical transfer function. For given magnification ratio and relative aperture, the lateral chromatic aberration is a function of wavelength and image height. For finite image distance, the latera
46、l chromatic aberration, T(), in the measurement plane is given by: T() = u() u(r) (2) where u(r) = 0. 4.7 Weighted lateral chromatic aberration The weighted lateral chromatic aberration, T(W), is defined as the radial variation in image height, u(W), for the weighted spectral distribution, W(), rela
47、tive to the image height, u(WR), for the weighted spectral reference distribution, WR(). For given magnification ratio and relative aperture, the weighted lateral chromatic aberration in the measurement plane is a function of image height. For finite image distance: T(W) = u(W) u(WR) (3) where u(WR)
48、 = 0. As in 4.6, this requires a numerical evaluation of the line spread function, here with weighted spectral distribution, W(). 4.8 Form and extent of the edge spread function (ESF) 4.8.1 General In addition to the lateral chromatic aberration as a displacement between the median values of the edg
49、e spread functions for the reference and measurement wavelength or spectral weighting, one shall judge the degradation in image quality with the help of the form of the line or edge spread function for the different wavelengths or spectral weightings. This will give information in the space domain alternatively to the optical transfer function in the spatial frequency domain. The edge spread function will be used, because, in general, its structure is relati
