EN ISO 25178-602:2010

SLOVENSKI STANDARD
01-november-2010
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Geometrical product specifications (GPS) - Surface texture: Areal - Part 602: Nominal
characteristics of non-contact (confocal chromatic probe) instruments (ISO 25178-
602:2010)
Geometrische Produktspezifikation (GPS) - Oberflächenbeschaffenheit: Flächenhaft -
Teil 602: Merkmale von berührungslos messenden Geräten (mit chromatisch konfokaler
Sonde) (ISO 25178-602:2010)
Spécification géométrique des produits (GPS) - État de surface: surfacique - Partie 602:
Caractéristiques nominales des instruments de mesure sans contact (instruments à
sonde chromatique confocale) (ISO 25178-602:2010)
Ta slovenski standard je istoveten z: EN ISO 25178-602:2010
ICS:
17.040.20 Lastnosti površin Properties of surfaces
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN STANDARD
EN ISO 25178-602
NORME EUROPÉENNE
EUROPÄISCHE NORM
July 2010
ICS 17.040.20
English Version
Geometrical product specifications (GPS) - Surface texture:
Areal - Part 602: Nominal characteristics of non-contact
(confocal chromatic probe) instruments (ISO 25178-602:2010)
Spécification géométrique des produits (GPS) - État de Geometrische Produktspezifikation (GPS) -
surface: Surfacique - Partie 602: Caractéristiques Oberflächenbeschaffenheit: Flächenhaft - Teil 602:
nominales des instruments sans contact (à capteur Merkmale von berührungslos messenden Geräten (mit
confocal chromatique) (ISO 25178-602:2010) chromatisch konfokaler Sonde) (ISO 25178-602:2010)
This European Standard was approved by CEN on 6 May 2010.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European
Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national
standards may be obtained on application to the CEN Management Centre or to any CEN member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by translation
under the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as the
official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2010 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 25178-602:2010: E
worldwide for CEN national Members.

Contents Page
Foreword .3

Foreword
This document (EN ISO 25178-602:2010) has been prepared by Technical Committee ISO/TC 213
"Dimensional and geometrical product specifications and verification" in collaboration with Technical
Committee CEN/TC 290 “Dimensional and geometrical product specification and verification” the secretariat of
which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an identical
text or by endorsement, at the latest by January 2011, and conflicting national standards shall be withdrawn at
the latest by January 2011.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights.
According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following
countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech
Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,
Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,
Sweden, Switzerland and the United Kingdom.
Endorsement notice
The text of ISO 25178-602:2010 has been approved by CEN as a EN ISO 25178-602:2010 without any
modification.
INTERNATIONAL ISO
STANDARD 25178-602
First edition
2010-07-01
Geometrical product specifications
(GPS) — Surface texture: Areal —
Part 602:
Nominal characteristics of non-contact
(confocal chromatic probe) instruments
Spécification géométrique des produits (GPS) — État de surface:
Surfacique —
Partie 602: Caractéristiques nominales des instruments sans contact (à
capteur confocal chromatique)
Reference number
ISO 25178-602:2010(E)
©
ISO 2010
ISO 25178-602:2010(E)
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ii © ISO 2010 – All rights reserved

ISO 25178-602:2010(E)
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Summary of metrological characteristics.15
Annex A (normative) Classification of the different configurations for areal surface texture
scanning instrument .16
Annex B (informative) General principles .17
Annex C (normative) Concept diagrams .25
Annex D (informative) Relation to the GPS matrix .27
Bibliography.29

ISO 25178-602:2010(E)
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 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 and
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, 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 casting 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 25178-602 was prepared by Technical Committee ISO/TC 213, Dimensional and geometrical product
specifications and verification.
ISO 25178 consists of the following parts, under the general title Geometrical product specifications (GPS) —
Surface texture: Areal:
⎯ Part 2: Terms, definitions and surface texture parameters
⎯ Part 3: Specification operators
⎯ Part 6: Classification of methods for measuring surface texture
⎯ Part 7: Software measurement standards
⎯ Part 601: Nominal characteristics of contact (stylus) instruments
⎯ Part 602: Nominal characteristics of non-contact (confocal chromatic probe) instruments
⎯ Part 603: Nominal characteristics of non-contact (phase-shifting interferometric microscopy) instruments
⎯ Part 701: Calibration and measurement standards for contact (stylus) instruments
The following parts are under preparation:
⎯ Part 604: Nominal characteristics of non-contact (coherence scanning interferometry) instruments
⎯ Part 605: Nominal characteristics of non-contact (point autofocusing) instruments
iv © ISO 2010 – All rights reserved

ISO 25178-602:2010(E)
Introduction
This part of ISO 25178 is a geometrical product specification standard and is to be regarded as a general
GPS standard (see ISO/TR 14638). It influences chain link 5 of the chain of standards on roughness profile,
waviness profile and primary profile and areal surface texture.
For more detailed information on the relationship of this standard to the GPS matrix model, see Annex D.
The confocal chromatic optical principle can be implemented in various set-ups. The configuration described in
this document comprises three basic elements: an optoelectronic controller, a linking fibre optic cable and a
chromatic objective (sometimes called “optical pen”).
Several techniques are possible to create the axial chromatic dispersion or to extract the height information from
the reflected light. In addition to implementations as point sensors, chromatic dispersion may be integrated into
line sensors and field sensors. Annex B describes in detail confocal chromatic imaging and its implementation into
distance measurement probes.
This type of instrument is mainly designed for areal measurements, but it is also able to perform profile
measurements.
This part of ISO 25178 describes the metrological characteristics of an optical profiler using a confocal
chromatic probe based on axial chromatic dispersion of white light, designed for the measurement of areal
surface texture.
For more detailed information on the chromatic probe instrument technique, see Annex B. Reading this annex
before the main body may lead to a better understanding of this part of ISO 25178.

INTERNATIONAL STANDARD ISO 25178-602:2010(E)

Geometrical product specifications (GPS) — Surface texture:
Areal —
Part 602:
Nominal characteristics of non-contact (confocal chromatic
probe) instruments
1 Scope
This part of ISO 25178 defines the design and metrological characteristics of a particular non-contact
instrument for measuring surface texture using a confocal chromatic probe based on axial chromatic
dispersion of white light.
2 Normative references
The 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 3274:1996, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Nominal
characteristics of contact (stylus) instruments
ISO 4287, Geometrical Product Specifications (GPS) — Surface texture: Profile method — Terms, definitions
and surface texture parameters
ISO 10360-1, Geometrical Product Specifications (GPS) — Acceptance and reverification tests for coordinate
measuring machines (CMM) — Part 1: Vocabulary
ISO/IEC Guide 99:2007, International vocabulary of metrology — Basic and general concepts and associated
terms (VIM)
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 3274, ISO 4287, ISO 10360-1,
ISO/IEC Guide 99 and the following apply.
NOTE Several of the terms given below are common to other types of instruments that use single point sensors and
lateral scanning.
ISO 25178-602:2010(E)
3.1 General terms and definitions
3.1.1
coordinate system of the instrument
orthonormal system of axes (X,Y,Z) defined as:
⎯ (X,Y) is the plane established by the areal reference guide of the instrument;
⎯ the Z axis is mounted parallel to the optical axis and is perpendicular to the (X,Y) plane
NOTE Normally, the X-axis is the tracing axis and the Y-axis is the stepping axis.
3.1.2
measurement loop
closed chain which comprises all components connecting the workpiece and the chromatic probe (3.3.2), e.g.
the means of positioning, the workholding fixture, the measuring stand, the drive unit (3.2.3 and 3.2.4) and
the probing system (3.3.1)
See Figure 1.
NOTE The measuring loop will be subjected to external and internal disturbances which influence the measurement
uncertainty.
Key
1 coordinate system of the instrument
2 measurement loop
Figure 1 — Coordinate system and measurement loop of the instrument
3.1.3
real surface of a workpiece
set of features which physically exist and separate the entire workpiece from the surrounding medium
[ISO 14660-1:1999, definition 2.4]
2 © ISO 2010 – All rights reserved

ISO 25178-602:2010(E)
3.1.4
real electro-magnetic surface
surface obtained by the electro-magnetic interaction with the real surface of a work piece
1)
[ISO 14406:— , definition 3.2.2]
NOTE The real electro-magnetic surface considered for the instrument described in this part of ISO 25178 may be
different from the real electro-magnetic surface for other types of optical instruments.
3.1.5
primary extracted surface
finite set of data points sampled from the primary surface
1)
[ISO 14406:— , definition 3.7]
3.1.6
measurement error
error of measurement
error
measured quantity value minus a reference quantity value
NOTE 1 The concept of “measurement error” can be used both
a) when there is a single reference quantity value to refer to, which occurs if a calibration is made by means of a
measurement standard with a measured quantity value having a negligible measurement uncertainty or if a
conventional quantity value is given, in which case the measurement error is known, and
b) if a measurand is supposed to be represented by a unique true quantity value or a set of true quantity values of
negligible range, in which case the measurement error is not known.
NOTE 2 Measurement error should not be confused with production error or mistake.
[ISO/IEC Guide 99:2007, definition 2.16]
3.1.7
systematic measurement error
systematic error of measurement
systematic error
component of measurement error (3.1.6) that in replicate measurements remains constant or varies in a
predictable manner
NOTE 1 A reference quantity value for a systematic measurement error is a true quantity value, or a measured quantity
value of a measurement standard of negligible measurement uncertainty, or a conventional quantity value.
NOTE 2 Systematic measurement error, and its causes, can be known or unknown. A correction (3.1.11) can be
applied to compensate for a known systematic measurement error.
NOTE 3 Systematic measurement error equals measurement error minus random measurement error (3.1.8).
[ISO/IEC Guide 99:2007, definition 2.17]
3.1.8
random measurement error
random error of measurement
random error
component of measurement error (3.1.6) that in replicate measurements varies in an unpredictable manner

1) To be published.
ISO 25178-602:2010(E)
NOTE 1 A reference quantity value for a random measurement error is the average that would ensue from an infinite
number of replicate measurements of the same measurand.
NOTE 2 Random measurement errors of a set of replicate measurements form a distribution that can be summarized
by its expectation, which is generally assumed to be zero, and its variance.
NOTE 3 Random measurement error equals measurement error minus systematic measurement error (3.1.7).
[ISO/IEC Guide 99:2007, definition 2.19]
3.1.9
adjustment of a measuring instrument
adjustment
set of operations carried out on a measuring system so that it provides prescribed indications corresponding
to given values of a quantity to be measured
NOTE 1 Types of adjustment of a measuring system include zero adjustment of a measuring system, offset adjustment,
and span adjustment (sometimes called gain adjustment).
NOTE 2 Adjustment of a measuring system should not be confused with calibration, which is a prerequisite for
adjustment.
NOTE 3 After an adjustment of a measuring system, the measuring system must usually be recalibrated.
[ISO/IEC Guide 99:2007, definition 3.11]
NOTE 4 This is an operation normally carried out by the instrument manufacturer because it requires specialized
equipment and knowledge that users normally do not have.
3.1.10
user adjustment
〈measuring instrument〉 adjustment of a measuring instrument (3.1.9) employing only the means at the
disposal of the user
NOTE This is an operation normally carried out by the user. It involves the use of a measurement standard, usually
supplied with the instrument. The result of this operation automatically or manually adjusts certain parameters in order for
the instrument to operate correctly.
3.1.11
correction
compensation for an estimated systematic effect
NOTE 1 See ISO/IEC Guide 98-3:2008, definition 3.2.3, for an explanation of “systematic effect”.
NOTE 2 The compensation can take different forms, such as an addend or a factor, or can be deduced from a table.
[ISO/IEC Guide 99:2007, definition 2.53]
3.1.12
residual correction error
difference between the value of a quantity obtained after correcting the systematic measurement error
(3.1.7) and the real value of this quantity
NOTE The residual error is composed of random errors (3.1.8) and uncorrected systematic errors.
4 © ISO 2010 – All rights reserved

ISO 25178-602:2010(E)
3.2 Terms and definitions relative to the lateral scanning system
3.2.1
lateral scanning system
system that performs the scanning of the surface to be measured in the (X,Y) plane
NOTE Typically, the lateral scanning system is composed of the drive unit X (3.2.3) and the drive unit Y (3.2.4).
3.2.2
areal reference guide
component of the instrument that generates the reference surface in which the probing system (3.3.1) moves
relative to the surface being measured according to a theoretically exact trajectory
NOTE In the case of areal surface texture measurement instruments, the reference guide establishes a reference
surface (see ISO 25178-2). It can be achieved through the use of two perpendicular reference guides (see ISO 3274:1996,
3.3.2) or one reference surface guide.
3.2.3
drive unit X
component of the instrument that moves the probing system (3.3.1) or the surface being measured along the
reference guide on the X-axis and returns the horizontal position of the measured point in terms of lateral X
coordinate of the profile
3.2.4
drive unit Y
component of the instrument that moves the probing system or the surface being measured along the
reference guide on the Y-axis and returns the horizontal position of the measured point in terms of lateral Y
coordinate of the profile
3.2.5
lateral position sensor
component of the drive unit that provides the lateral position of the measured point
NOTE The lateral position can be measured or inferred by using, for example, a linear encoder, a laser
interferometer, or a counting device coupled with a micrometer screw.
3.3 Terms and definitions relative to the probing system
3.3.1
probing system
〈surface texture, confocal chromatic probe〉 components of the instrument called confocal chromatic probe,
consisting of an optoelectronic controller, a fibre optic cable and a confocal chromatic objective
3.3.2
chromatic probe
device that converts the height of a point on the surface into a signal during measurement, using the confocal
chromatic dispersion of a white light source
NOTE Chromatic dispersion can be realized by using various optic configurations (see Annex B).
3.3.3
angular aperture
angle of the cone of light entering an optical system from a point on the surface being measured
3.3.4
half aperture angle
α
one half of the angular aperture (3.3.3)
ISO 25178-602:2010(E)
See Figure 2.
NOTE This angle is sometimes also called the half cone angle.

Key
L lens or optical system
P focal point
α half aperture angle
Figure 2 — Half aperture angle
3.3.5
numerical aperture
A
N
sine of the half aperture angle (3.3.4) multiplied by the refractive index n of the surrounding medium
An= sinα
N
NOTE 1 In air, n approximately equals 1 and can be omitted from the equation.
NOTE 2 For a chromatic probe (3.3.2), the numerical aperture is dependent on the wavelength of light. Typically the
numerical aperture is specified for the wavelength focused at the middle of the vertical range (3.3.14).
3.3.6
confocal chromatic microscopy
surface topography measurement method consisting of a confocal microscope with chromatic objective
integrated with a detection device (e.g. spectrometer) whereby the surface height at a single point is sensed
by the wavelength of light reflected from the surface
[ISO 25178-6:2010, 3.3.7]
3.3.7
achromatic objective
objective that produces a single focus for all wavelengths of the transmitted light
3.3.8
objective with axial chromatic dispersion
objective that produces a different focus along its optical axis for each wavelength of the transmitted light
3.3.9
light source
〈chromatic probe〉 source of light containing a continuum of wavelengths in a predefined spectral region
NOTE 1 The spectral region emitted by the source should be compatible with the spectral bandwidth of the detector.
NOTE 2 Typically, this spectral region extends from wavelength values of 0,4 µm to 0,8 µm.
6 © ISO 2010 – All rights reserved

ISO 25178-602:2010(E)
3.3.10
light source pinhole
small hole placed following the light source (3.3.9), transforming the light source into a point light source
NOTE See notes in 3.3.11.
3.3.11
discrimination pinhole
small hole placed in front of the detector, providing depth discrimination on a beam reflected from the sample
surface by blocking defocused light
NOTE 1 The system contains two pinholes: the first one is the light source pinhole (3.3.10). It defines a small spot of
light that acts as the point light source for the instrument. The second one is the discrimination pinhole. It limits the
transmitted beam to the part that is in focus on the sample surface and is reflected by it along the optical axis (see
Figure B.1).
NOTE 2 In practice, the pinholes are obtained by using a fibre optic which provides spatial discrimination and allows
the optical head to be used away from the optoelectronic controller.
3.3.12
chromatic depth of field
distance between the focal point of the shortest wavelength and the focal point of the longest wavelength of
the spectral continuum emitted by the source
NOTE This definition differs from the typical definition for depth of field used in other optical systems, such as a
conventional microscope.
3.3.13
working distance
〈chromatic probe〉 distance measured along the optical axis between the element closest to the surface and
the point on the surface located in the middle of the vertical range (3.3.14)
3.3.14
vertical range
〈chromatic probe〉 distance measured between the focal point of the shortest wavelength and the focal point of
the longest wavelength detected on the spectrometer
NOTE The vertical range depends on the chromatic depth of field (3.3.12) and on the spectral range of the
spectrometer.
3.3.15
optical pen
part of a chromatic probe (3.3.2) containing the chromatic lens and located close to the surface during the
measurement
3.3.16
stray light signal
signal composed of the stray light entering the discrimination pinhole (3.3.11), sensed by the detector when
no sample is present, and the internal signal produced by the detector itself
NOTE The stray light signal is generally captured during a calibration procedure in order to correct the
measurements.
ISO 25178-602:2010(E)
3.4 Metrological characteristics of the instrument
3.4.1
metrological characteristic
MC
〈measuring equipment〉 characteristic of measuring equipment, which may influence the result of
measurement
[ISO 14978:2006, definition 3.12]
NOTE 1 Calibration of metrological characteristics may be necessary.
NOTE 2 The metrological characteristics have an immediate contribution to measurement uncertainty.
3.4.2
measuring volume
range of the instrument stated as simultaneous limits on all spatial coordinates measured by the instrument
NOTE For areal surface texture measuring instruments, the measuring volume is defined by
⎯ the measuring range of the drive unit X (3.2.3) and the drive unit Y (3.2.4),
⎯ the measuring range of the probing system (3.3.1).
3.4.3
hysteresis
property of measuring equipment, or a characteristic whereby the indication of the equipment or value of the
characteristic depends on the orientation of the preceding stimuli
NOTE 1 Hysteresis can also depend, for example, on the distance travelled after the orientation of stimuli has changed.
[ISO 14978:2006, definition 3.24]
NOTE 2 For lateral scanning systems, the hysteresis is mainly a repositioning error.
3.4.4
response curve
F , F , F
x y z
graphical representation of the function that describes the relation between the actual quantity and the
measured quantity
See Figure 3.
NOTE 1 An actual quantity in X (respectively Y or Z) corresponds to a measured quantity x (respectively y or z ).
m m m
NOTE 2 The response curve can be used for adjustments and error corrections.
3.4.5
amplification coefficient
α , α , α
x y z
slope of the linear regression curve obtained from the response curve
See Figure 4.
NOTE 1 There will be amplification coefficients applicable to the X, Y and Z quantities.
NOTE 2 The ideal response is a straight line with a slope equal to 1 which means that the values of the measurand are
equal to the values of the input quantities.
8 © ISO 2010 – All rights reserved

ISO 25178-602:2010(E)
Key
1 response curve 3 measured quantities
2 assessment of the response curve by polynomial approximation 4 input quantities
Figure 3 — Example of a non-linear response curve

Key
1 measured quantities 4 linearized response curve
2 input quantities 5 straight line whose slope is the amplification coefficient α
3 ideal response curve 6 local residual correction error before adjustment
Figure 4 — Example of the linearization of a response curve
ISO 25178-602:2010(E)
3.4.6
instrument noise
internal noise added to the output signal caused by the instrument if ideally placed in a noise-free environment
NOTE 1 Internal noise can be caused by the electronic noise such as amplifiers.
NOTE 2 This noise typically has high frequencies which limit the ability of the instrument to detect small scale surface
texture.
NOTE 3 The S-filter specified in ISO 25178-3 can reduce this noise.
3.4.7
static noise
N
s
combination of the instrument and environmental noise on the output signal when the instrument is not
scanning laterally
NOTE 1 Environmental noise is caused by, e.g., seismic, sonic and external electro-magnetic disturbances.
NOTE 2 Notes 2 and 3 of 3.4.6 also apply to this definition.
3.4.8
dynamic noise
N
d
noise occurring during the motion of the drive units on the output signal
NOTE 1 Notes 2 and 3 of 3.4.6 also apply to this definition.
NOTE 2 Dynamic noise includes the static noise (3.4.7).
3.4.9
sampling interval in X
D
x
distance between two adjacent measured points along the X-axis
3.4.10
sampling interval in Y
D
y
distance between two adjacent measured points along the Y-axis
3.4.11
digitization step in Z
D
z
smallest height variation along the Z-axis between two ordinates of the extracted surface
NOTE 1 The height of a point is evaluated by searching for the position of the maximum peak on the spectrometer
curve. Although the lateral resolution of the spectrometer is relatively small (small number of pixels), the digitization step in
Z of the chromatic probe (3.3.2) is improved with the use of sub-pixel algorithms.
NOTE 2 Several algorithms may be used to detect the position of the maximum peak. The most likely ones are given in
Table 1.
10 © ISO 2010 – All rights reserved
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