Tiêu chuẩn iso 14490 7 2016

© ISO 2016 Optics and photonics — Test methods for telescopic systems — Part 7 Test methods for limit of resolution Optique et photonique — Méthodes d’essai pour systèmes télescopiques — Partie 7 Méth[.]

Optics and photonics — Test methods

Part 7:

Optique et p oto ique — Méth des d’essai p ur systèmes

téle sco iques —

Partie 7: Méth de s d’e ssai p ur limite de résolution

S con edition

2 16-1 -1

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F reword i v

Introduction v

1 Sc ope 1

2 Nor mati ve r eferenc es 1

3 Terms an definitions 1

4 Metho of deter minatio of the lmit of r esolutio 1

4.1 General 1

4.2 Tes eq ipment 1

4.3 Pr eparation an car ying out of measur ements 3

4.4 Dete mination of r esult 3

5 Test rep r t 4

A nne x A (informative)Dimensions of a bar -type test tar g et for deter mination of the lmit of r esolutio of telesc opic systems 5

Biblog raphy 10

ISO (he Int ernational Org nization for Stan ardization) is a worldwidefede ation of national s an ards

b dies (ISO membe b dies) The work of pr p ring Int ernational Stan ards is normaly car ied out

through ISO t ech ical committ ees Each membe b dy int er st ed in a subje t for w hich a t ech ical

committ ee has be n es a lshed has the right t o be r pr sent ed on that committ ee Int ernational

org nizations, g ove nmental an non-g ove nmental, in laison with ISO, also take part in the work

ISO cola orat es closely with the Int ernational Ele trot ech ical C mmis ion (IEC) on al matt ers of

ele trot ech ical s an ardization

The proc d r s used t o develo this document an those int en ed for it furthe maint enanc ar

desc ibed in the ISO/IEC Dir ctives, Part 1 In p rticular the dife ent a pro al c it eria ne ded for the

dife ent ty es of ISO document should be not ed This document was draft ed in ac ordanc with the

edit orial rules of the ISO/IEC Dir ctives, Part 2 ( e www.iso.org dir ctives)

A tt ention is drawn t o the p s ibi ity that some of the element of this document ma be the subje t of

p t ent right ISO shal not be held r sponsible for identifying any or al such p t ent right Detais of

any p t ent right identified d ring the develo ment of the document wi be in the Introd ction an / r

on the ISO ls of p t ent de larations r c ived ( e www.iso.org p t ent )

Any trade name used in this document is information given for the convenienc of use s an does not

cons itut e an en orsement

For an ex lanation on the meaning of ISO spe ific t erms an ex r s ions r lated to conformity as es ment,

as wel as information a out ISO’s adhe enc to the Wor ld Trade Org nization (WTO) principles in the

Te h ical Bar ie s to Trade (TBT) se the folowing URL: www.iso.org/ iso/for word.html

The committ ee r sponsible for this document is ISO/TC 1 2, Optic s a d p oto ic s , Subcommitt ee SC 4,

Teles c opic sys tems

This se on edition canc ls an r plac s the f irs edition (ISO 1449 -7 :2 0 ), w hich has be n

t ech icaly r vised with the folowing chang es:

— ad ition of a new sent enc in A.4 “Alt ernatively, a t es p tt ern down t o 2

-1 3

= 0,7 isac epta le.” ;

— cor e t ed Ta le A.2, las row: 3 2 r plac d b 3 0

A ls of p rt in theISO 14 90 se ies can be fou d on the ISO website

The e ar v rious charact eris ics w hich ar r lev nt or o e al imag e q al ty of t elesco ic sy st emsan

o se v tional t elesco ic ins rument Two imp rtant charact eris ics ar the lmit of r solution and the

o tical trans e fu ction

This document spe ifies the t es method for the det ermination of the lmit of r solution of t elesco ic

sy st ems an o se v tional t elesco ic ins rument Optical trans e fu ction measur ment as a pled

t o t elesco ic sy st emsis spe ified in ISO 9 3 -3

Besidesthe l mit of r solution an the o tical trans e function, furthe charact eris ics ar r lev nt or

an as es ment of the imag e q alty;the mos important of them ar the folowing:

— se on ary spe trum (dispe sive a e rations);

— dist ortion;

— vignet ing;

— colour mat ching

The se on ary spe trum of the t es spe imen can prod c colour fring es sur ou ding o se ved o je t

(espe ialy at high contras edg es) w hich can lo k lke colour d neon tube lght

The pe c ived imag e might ha e b r el or pincushion dist ortion Pincushion dist ortion is conside ed t o

give a mor natural impr s ion of the o se ved o je t w hen swivel ing the t es spe imen

V ignet ing can lead t o a pe c iv able int ensity degradation from the c ntr to the edg e of the field of view

Colour mat ching is the ac uracy of the colour r n ition of an o je t o se ved with the t es spe imen

Any colour deviation might be d e t o the lens mat erial or t o co tings

Optics and photonics — Test methods for telesc opic

Part 7:

This document spe ifies the t es methods for the det ermination of the lmit of r solution of t elesco ic

sy st ems and o se v tional t elesco ic ins rument

2 Normati ve r eferences

The folowing document ar r fe r d t o in the t ext in such a wa that some or al of their cont ent

cons itut es r q ir ment of this document F or dat ed r fe enc s, only the edition cit ed a ples F or

un at ed r fe enc s, the lat es edition of the r fe enc d document ( inclu ing any amen ment ) a ples

ISO 14 90-1:2 0 , Optic s a d o tic al ins truments — Tes t meth ds fr telesc opic sys tems — Part 1: Tes t

meth ds fr b s ic charac te i s tic s

3 Terms and definitions

F or the purposes of this document, the t erms an def initions given in ISO 141 2-1 a ply

ISO an IEC maintain t erminolo ical data ases for use in s an ardization at the folowing ad r s es:

— IECEle tro edia: a aia le at ht p:/ www.ele tro edia.org

— ISO Onlne brow sing plat orm:a ai a le at ht p:/ www.iso.org o p

4 Method ofdetermination ofthe l mit ofr esolution

The lmit of r solution of a t elesco ic sy st em is the minimum angular dis anc betwe n c ntr lnes of

two adjac nt bright (or dark)b rs of the b r-ty e r solution t es targ et w hose dir ction can be det ect ed

w hen viewing through the t es spe imen

4.2 Test equipment

The l mit of r solution of t elesco ic sy st ems shal be det ermined with the t es ar ang ement shown in

Figur 1

The b r-ty e r solution t es targ et has contras , as given b F ormula (1):

K =

−

+

≥

w he e

τ

t

is the transmit anc of a transluc nt part of the r solution t es targ et ;

τ

op

is the transmit anc of an o aq e p rt of the r solution t es targ et

Ther solution t es targ et shal be plac d at he focal plane of the col mat or lens

F or sy st ems that r q ir the lmit of r solution t o be measur d with a focus set ing othe than inf inity,

the p sition of the r solution t es targ et with r spe t t o the col imat or lens shal be adjust ed in orde t o

o tain it imag eat the spe if ied dis anc from the t es spe imen

The b r-ty e r solution t es targ et is a glas plat e bearing a pictur that consis s of bright b rs ha ing

dife ent widths on a dark backgroun , the dir ctions of w hich ar ve tical, horizontal an diag onal in

± 45 angular degr es

Thedimensions of one ac epta le design of b r-ty e r solution t es targ et ar given in An ex A

The r solution t es targ et shal be i luminat ed u iformly (mean i uminanc ± % Peak t o Valey) b

means of a l ght sour e with a cor elat ed colour t empe atur of 5 0 0 K t o 6 0 0 K, con ense an

difuse for non-daz lng o se v tion con itions The luminanc of the r solution t es targ et shal be

o timum for o se v tion of it imag e

Thediamet er of the col mat or lens shal at leas ex ce d 1,2 times the diamet er of the entranc pupi of

the t es spe imen The focal length of the col mat or lens shal be at leas five times that of the o je tive

of the t es spe imen

Thema nif ication of the a uxi iary t elesco e shal not r d c the diamet er of the exit pupi of the w hole

sy st em below 0,8 mm

Key

1 lig ht sour ce

2 con enser

3 difuser

4 b r-type r esolution test targ et

5 colimator lens

6 test specimen

7 aux iliary teles ope

T e aux iliary teles ope should not b used if the ang ular limit of r esolution b hin the eyepiece of the test specimen

is wor e than 2’ to 3’ an the diameter of the ex it p pil is b low 1mm

Figure 1 — Test ar ang ement for me surement of the l mit of resolutio (s hematic)

4.3 Preparation and car ying out of me sur ements

Stra l ght an vibration shal be minimiz d (an if p s ible elminat ed) from the t es set up

Che k the cleanlnes of the o tical surfac s of the lenses of the t es spe imen, the col mat or lens,

the con ense , an the a uxi ary t elesco e No trac s of lubricant , f ing erprint , mois ur , or d s ar

alowed

S le t the siz n mbe of the r solution t es targ et ac ording t o the focal length of the col mat or lens

an the lmit of r solution of thet es spe imen (for ins anc , se Ta le A.2 or use the formula given for

the angular r solution def ined in ISO 141 2)

If an auxi ary t elesco e is used, adjus it eyepie e ac ording t o the o se ve ’s eye t o alow sharp

viewing of the t elesco e r ticle The auxi ary t elesco e an the eye of the o se ve shal not l mit the

as es ment of the r solution Aft er that, focus the a uxi ary t elesco eon the imag e of the r solution t es

targ et w hich is locat ed in the focal plane of the col mat or lens

F ocus the t es spe imen on the imag e of the r solution t es targ et ; then p sition the t es spe imen an

the auxi ary t elesco e co xialy with the col mat or lens

S t he eyepie e of the t es spe imen in a position w hich ena les sharp viewing of the r ticle of the t es

spe imen through the auxi ary t elesco e If no r ticle is pro ided, adjus the eyepie e t o z ro dio tr s

Det ermine the lmit of r solution of the t es spe imen in thec ntr of the f ield of view

During o se v tion through the eyepie e of the auxi iary t elesco e, the ma imum sharpnes of b rs of

a p tt ern at lowes sharpnes in one group of the r solution t es targ et shal be o tained b means of

r focusing the t es spe imen If no focusing is a ai a le in the t es spe imen, the ma imum sharpnes

of b rs of a p tt ern at lowes sharpnes in one group of the r solution t es targ et shal be o tained b

r focusing the auxi ary t elesco e

During suc es ive viewing of imag es of c rtain groups of the r solution t es targ et ha ing dife ent

sp tial fr q encies, a group of the r solution t es targ et hal be fou d w hich ena les easy det ection of

al four b r dir ctions This shal be achieved without r focusing for the dife ent b r dir ctions This

groupshal be locat ed in the c ntr of the f ield of view of the t es spe imen

4.4 Determination of r esults

From the siz n mbe of the r solution t es targ et group that ena les the det ection of al four p tt ern

dir ctions, det erminethe b r width, b

Calculat e the angular dis anc , φ, in se onds of angle, betwe n the c ntr lnes of adjac nt bright (or

dark) b rs of each r solution t es targ et group ac ording t o F ormula (2):

2

2 62 5

b

f

k

′

(2)

w he e

b isthe b r width, in mm;

f

k

′

is the focal length of thecol imat or lens, in mm;

5 Test repor t

A tes r p rt hal be pr sented an shal inclu e the gene al information spe if ied in ISO 1449 -1:20 5,

Clause 1 , the r sult of the tes as spe if ied in 4.4 a ove an information on the tes target used for

the tes

A nne x A

(informative)

Dimensions of a bar-type test tar g et for determination of the l mit

of resolution of telesc opic systems

A 1 Resolution test tar g et layout

The r solution t es targ et consis s of 2 groups, as shown in Figur A.1, an two p irs of paralel,

eq aly sp c d marks The dis anc betwe n the c ntr s of the marks that def ines the siz of the t es

targ et is caled the t es targ et b se

NOTE Dimensions of resolution test arg ets are given in Ta le A.1

Figure A.1 — Resolutio test targ et lay ut

A 2 Layout of g r oups ofresolution test tar g et

Each group of the r solution t es targ et consis s of four p tt erns formed b f ive b rs each The b rs ha e

eq al lengths and widths an ar ar ang ed as shown in Figur A.2 The int erv ls betwe n adjac nt b rs

ar eq al t o the b r width

A 3 Dimensions

NOTE Dimensions of resolution t est arg ts are given in Ta le A.1

Figure A.2 — Gro p of the resolutio test targ et

A 4 Bar width

The b r width, b, in the r solution t es targ et shal de r ase from the group no 1 t o thegroup no 2 in

ac ordanc with the g eometric pro r s ion ha ing the b se 2

-1 1

= 0, 94 Alt ernatively, a t es p tt ern

down t o 2

-1 3

= 0,7 isac epta le

NOTE S e Ta le A.1for dimensions

A 5 Number of bars

The n mbe , N, of b rs pe mi imetr for any t es targ et group n mbe should be det ermined b division

of 1 0 0µm b the dis anc betwe n the c ntr lnes of adjac nt bright (or dark) b rs (2 ) in µm

Table A.1 — Dimensio s of resolutio test targ ets

Dimensions in milimetr es

Designation

a

Tes targ et n mbe

a

S e Fig re A.1 an Fig re A.2

a

Tes targ et n mbe

a

S e Fig re A.1 an Fig re A.2

A 6 A ng ular distanc e betwe n c entrel nes of adjac ent bar

The angular dis anc , φ, in se on s of angle, betwe n the c ntr l nes of adjac nt bright (or dark) b rs of

each r solution t es targ et group is calculat ed in ac ordanc with F ormula (2)

The v lues of the angular dis anc , φ, w hich depen on the focal length of the col imat or o je tive, f

k

′

an the n mbe of b rs, N, for the t es targ et pe ified in this an ex ar given in Ta le A.2

Table A.2 — Values of the angula distance, φ, for the test targ et specified in A.1 t o A.5

Numbe s of targ et groups for

a t es target n mbe

Bar

width

Bars

Angular dis anc , φ, between the mid les of

adjac nt b rs for a given col imat or focal length, f

k

′

Tes targ et n mbe

f

k

′

mm

b r /

mm

60 1 0 0 1 2 0 1 60 2 5 0 30 0 50 0

Table A.1 (c ontin ed)

Numbe s of target groups for

a t es targ et n mbe

Bar

width

Bars

Angular dis anc , φ, between the mid les of

adjac nt b rs for a given col imat or focal length, f

k

′

Tes targ et n mbe

f

k

′

mm

b r /

mm

60 1 0 0 1 2 0 1 60 2 5 0 30 0 50 0

Table A.2 (c ontin ed)

Numbe s of targ et groups for

a t es target n mbe

Bar

width

Bars

Angular dis anc , φ, between the mid les of

adjac nt b rs for a given col imat or focal length, f

k

′

Tes targ et n mbe

f

k

′

mm

b r /

mm

60 1 0 0 1 2 0 1 60 2 5 0 30 0 50 0

Table A.2 (c ontin ed)

Bibl og raphy

[1] ISO 9 3 -3, Optic s a d o tic al ins truments — Optic al tra s fe f nc tio — Ap lc atio — Part 3 :

Telesc opes

[2] ISO 141 2-1, Optic s a d p oto ic s — Voc ab lary fr teles c opic sys tems — Part 1: G ene al te ms

a d alp a etic al indexes o te ms in ISO 1413 2