ISO 16331-1:2012
(Main)Optics and optical instruments — Laboratory procedures for testing surveying and construction instruments — Part 1: Performance of handheld laser distance meters
Optics and optical instruments — Laboratory procedures for testing surveying and construction instruments — Part 1: Performance of handheld laser distance meters
ISO 16331-1:2012 specifies procedures for checking compliance with performance specifications of handheld laser distance meters.
Optique et instruments d'optique — Méthodes d'essai de laboratoire des instruments d'observation et construction — Partie 1: Performance de télémètres laser de poche
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INTERNATIONAL ISO
STANDARD 16331-1
First edition
2012-05-01
Optics and optical instruments —
Laboratory procedures for testing
surveying and construction
instruments —
Part 1:
Performance of handheld laser distance
meters
Optique et instruments d’optique — Méthodes d’essai de laboratoire
des instruments d’observation et construction —
Partie 1: Performance de télémètres laser de poche
Reference number
ISO 16331-1:2012(E)
©
ISO 2012
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ISO 16331-1:2012(E)
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ii © ISO 2012 – All rights reserved
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ISO 16331-1:2012(E)
Contents Page
Foreword .iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms . 1
5 General information . 3
5.1 General . 3
5.2 Target reflectivity . 3
5.3 Background illumination . 3
5.4 Temperature of key components . 3
5.5 Atmospheric influence . 3
5.6 Display resolution . 3
5.7 Average deviation and uncertainty of measurement . 3
5.8 Relevant contribution to uncertainty . 4
5.9 Instruction for instrument specifications . 4
6 Test procedure for determining the compliance with accuracy specifications . 4
6.1 Test concept . 4
6.2 Requirements . 4
6.3 Configuration of check points . 5
6.4 Measurement procedure . 5
6.5 Calculation of deviations and uncertainty of measurement . 6
6.6 Statement of test result . 9
7 Test procedure for determining compliance with range specifications .10
7.1 Requirements .10
7.2 Description of measurement procedure .10
7.3 Calculation of deviation and uncertainty of measurement .10
7.4 Statement of test result . 11
Annex A (informative) Example of performance specification .12
Annex B (informative) Examples of determining compliance with accuracy specifications .13
Annex C (informative) Examples of determination of compliance with range specifications .26
Annex D (informative) Background illumination simulation .30
Annex E (informative) Target plates .32
Annex F (informative) Typical characteristics of natural targets .33
Bibliography .35
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ISO 16331-1:2012(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 16331-1 was prepared by Technical Committee ISO/TC 172, Optics and photonics, Subcommittee SC 6,
Geodetic and surveying instruments.
ISO 16331 consists of the following parts, under the general title Optics and optical instruments — Laboratory
procedures for testing surveying and construction instruments:
— Part 1: Performance of handheld laser distance meters
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ISO 16331-1:2012(E)
Introduction
Starting in 1993 several companies developed handheld laser distance meters and introduced them into the
market. With a growing number of different manufacturers, it became obvious that a standard was needed to
establish requirements for device specifications and to describe how to check compliance with the specified
performance of accuracy and range.
In comparison with ISO 17123, which specifies methods of checking compliance with the specifications by the
user of the instrument without any additional measurement equipment, ISO 16331 specifies the procedures to
be applied for checking compliance with the specifications by using additional laboratory equipment which the
typical user does not have access to.
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INTERNATIONAL STANDARD ISO 16331-1:2012(E)
Optics and optical instruments — Laboratory procedures for
testing surveying and construction instruments —
Part 1:
Performance of handheld laser distance meters
1 Scope
This part of ISO 16331 specifies procedures for checking compliance with performance specifications of
handheld laser distance meters.
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/IEC Guide 98-3, Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
measurement (GUM:1995)
ISO/IEC Guide 99, International vocabulary of metrology — Basic and general concepts and associated terms (VIM)
ISO 3534-1, Statistics — Vocabulary and symbols — Part 1: General statistical terms and terms used in probability
ISO 9849, Optics and optical instruments — Geodetic and surveying instruments — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO/IEC Guide 98-3, ISO/IEC Guide 99,
ISO 3534-1 and ISO 9849 apply.
4 Symbols and abbreviated terms
Table 1 — Symbols and abbreviated terms
AD absolute distance (as index of measurements and calculations)
Add additional contribution (as index extension of measurements and calculations)
BG background illumination (as index of measurements and calculations)
CP check point X
X
D distance
D reference distance
REF
mean value of a set of distances
D
mean value of a set of distances taken at the absolute distance test
D
AD
mean value of a set of distances taken at the background illumination test
D
BG
mean value of a set of distances taken at the temperature test
D
T
DR display resolution
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ISO 16331-1:2012(E)
Table 1 (continued)
Δ
deviation
deviation of the mean value of a set of measured distances in relation to the reference distance
ΔD
deviation of the mean value of a set of measured distances in relation to the reference distance at
ΔD
AD
the absolute distance test
additional deviation of the mean value of a set of measured distances at the high background
ΔD
BG,Add
illumination case in reference to the deviation of the mean value of a set of measured distances at
the low background illumination case
combined positive deviation of the mean value including background illumination and temperature
ΔD
C,max
influences
combined negative deviation of the mean value including background illumination and temperature
ΔD
C,min
influences
additional deviation of the mean value of a set of measured distances at the temperature test at 5 °C
ΔD
T05,Add
in reference to the deviation of the mean value at the temperature test at 25 °C
additional deviation of the mean value of a set of measured distances at the temperature test at
ΔD
T45,Add
45 °C in reference to the deviation of the mean value at the temperature test at 25 °C
deviation of an individual distance measurement in relation to the reference system value
ΔM
i
k extension factor for a level of confidence of 95 %
M Measurement value
M individual measurement value
i
N number of measurements taken at each check point
RT As index for measurements and calculations at range test
s experimental standard deviation
s experimental standard deviation at the absolute distance test
AD
s experimental standard deviation at the background illumination test
BG
s experimental standard deviation at the temperature test
T
T temperature (as index of measurements and calculations)
T05 Temperature 5 °C
T45 Temperature 45 °C
u
uncertainty of measurement
u uncertainty of measurement at the absolute distance test
AD
u uncertainty of measurement at the background illumination test
BG
u additional uncertainty of measurement at the high background illumination case in relation to the
BG,Add
uncertainty of measurement at the low background illumination case
u combined uncertainty
c
u uncertainty due to display resolution
DR
u uncertainty of the reference system at the absolute distance test
REF,AD
u uncertainty of the reference system at the background illumination test
REF,BG
u uncertainty of the reference system at the temperature test
REF,T
u uncertainty of measurements at range test
RT
u uncertainty of measurement at the temperature test
T
u additional uncertainty of measurement at higher or lower temperature in relation to the uncertainty
T,Add
of measurement at 25 °C
U
expanded uncertainty
x Index for individual cases
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ISO 16331-1:2012(E)
5 General information
5.1 General
The maximum measurement range on natural targets and the uncertainty of measurements provided by
handheld laser distance meters are influenced by various factors.
5.2 Target reflectivity
The higher the target reflectivity, the better the signal to noise ratio at the receiver; therefore better measurement
performance on natural targets is achievable. For more details, refer to Annex F.
As handheld laser distance meters are used on construction sites and for indoor applications, typical targets
are painted walls, bricks, concrete, wood, and similar targets. Special attention has to be paid to the effect of
penetration of the laser into certain materials e.g. white marble.
5.3 Background illumination
Background light in indoor applications is typically below 3 klx and therefore negligible. However, in outdoor
applications, the sunlight reflected by the target might reach an illuminance of up to 100 klx and might cause a
degradation of the signal to noise ratio and therefore a poorer performance of the instrument.
5.4 Temperature of key components
The temperature of the laser system and of the receiver system has an influence on the uncertainty of distance
measurement. Most of these instruments have a built-in temperature compensation system to minimize this
kind of influence.
5.5 Atmospheric influence
The maximum range and the accuracy of laser distance meters are influenced by meteorological conditions
at the moment of the measurements being taken. These conditions include variations in air temperature,
air pressure and humidity of the air. Distances calculated by handheld laser distance meters are based on
predefined meteorological conditions. To achieve accurate measurements, in particular at long distances,
these meteorological variables in the distance calculation shall be determined and the measured distance
shall be corrected accordingly.
5.6 Display resolution
The display resolution of a measurement instrument should be at least two times better than the specified
accuracy. For very accurate measurements, like in a calibration situation, a laser distance meter should offer a
unit setting which allows a display resolution that is at least five times better than the specified accuracy.
5.7 Average deviation and uncertainty of measurement
Even though the calculation of average values is necessary to find out systematic deviations, the typical
user of handheld laser distance meters is not willing to do so. The user rather wants to take only one single
measurement and wants to rely on the specified maximum tolerances. Therefore, it is the value of the combined
and expanded uncertainty of a single measurement that the user wants to see below the tolerance limits.
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ISO 16331-1:2012(E)
5.8 Relevant contribution to uncertainty
Table 2 — Relevant contribution to uncertainty
Uncertainty contribution Distribution Type
Reference system Normal B
Display resolution Rectangular B
Absolute distance test (internal noise at typical conditions) Normal A
Background illumination (additional offset and noise) Normal A
Temperature (additional offset and noise) Normal A
5.9 Instruction for instrument specifications
As customers of handheld laser distance meters usually are not used to the term “uncertainty of measurement”,
the manufacturers may use the expression “measurement accuracy” in their product specification.
Since the performance of a handheld laser distance meter depends on various conditions, the specification of
the product shall indicate the conditions that apply, e.g. distance dependency, target reflectivity, background
illumination and temperature range. It is mandatory to indicate typical error tolerances (indoor conditions) and
the maximum error tolerances (outdoor conditions).
For an example, see Annex A.
6 Test procedure for determining the compliance with accuracy specifications
6.1 Test concept
As mentioned before, the accuracy of handheld laser distance meters depends on various factors. To avoid
difficult test setups, the test concept of this International Standard focuses on the main influences, such as
measurement distance, temperature of instrument and background illumination.
The target reflectivity, which also can have an impact on the accuracy, is not tested directly by changing
targets with different reflectivity factors. The reason is that it is quite difficult to get targets with well defined,
homogeneous and stable reflectivity factors. In addition, the effect of a target with a lower reflectivity factor
of 25 % can be tested using a target with 100 % reflectivity at double distance. Therefore the effects of lower
reflectivity factors are indirectly tested at the absolute distance test described in 6.4.2.
6.2 Requirements
6.2.1 General
To determine compliance with the accuracy specifications for handheld laser distance meters, the following
measurement setup is used.
6.2.2 Apparatus
6.2.2.1 Target plate, meeting the following specifications:
Size: 0,25 m x 0,25 m.
Reflectivity: 95 % ± 5 % (see Annex E).
Orientation: perpendicular to the measurement direction.
Special attention is to be paid to the effect of penetration of the laser beam into certain materials (see Annex F).
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ISO 16331-1:2012(E)
6.2.2.2 Background illumination lamp, that shall achieve at least an illuminance of 30 klx on the used target plate.
Check with an illuminance meter (lux meter) directed perpendicularly to the target at 0,1 m distance from the target.
6.2.2.3 Temperature chamber, capable of heating the devices under test up to +45 °C and cooling them down
to +5 °C. The measurements can be taken inside a big temperature chamber or by taking the heated (or cooled)
devices out of the chamber and immediately taking the measurements on a known reference distance.
6.2.2.4 Calibrated reference distance measurement system, to determine the distance between target
and device under test. The uncertainty of measurement of the reference system shall be 20 % or less than the
expected uncertainty of measurement of the device under test.
6.3 Configuration of check points
Select 10 check points CP01 to CP10.
Check point CP10 shall be set either to the longest specified distance of the device under test or to the
maximum range of the reference distance measurement system. The following configuration of check points
takes into consideration that typical customers measure shorter distances more frequently than longer ones.
CP01
CP02
CP03
CP04
CP10
CP08 CP09
CP05 CP06 CP07
0 1 2 3 5 6 10 11 12 13 14 15 16 17 18 19 20 X
4 7 8 9
D(CP01) = 0.02 * D(CP10)
D(CP02) = 0.03 * D(CP10)
D(CP03) = 0.05 * D(CP10)
D(CP04) = 0.07 * D(CP10)
D(CP05) = 0.10 * D(CP10)
D(CP06) = 0.20 * D(CP10)
D(CP07) = 0.30 * D(CP10)
D(CP08) = 0.50 * D(CP10)
D(CP09) = 0.70 * D(CP10)
D(CP10) = max. distance
X Distance (m)
Figure 1 — Example: CP10 = 20 m
6.4 Measurement procedure
6.4.1 General
To determine compliance with accuracy specifications on natural targets for handheld laser distance meters,
the following procedure is recommended.
6.4.2 Absolute distance test
Target reflectivity: 95 % ± 5 %.
Background illumination: < 3 klx (indoor conditions).
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ISO 16331-1:2012(E)
Temperature: 25 °C ± 3 °C.
Define the check points (see 6.3).
At each check point, take and record one measurement with the reference distance measurement system and
10 measurements with the device under test. Ensure that the alignment of the handheld laser distance meter
to the target is correct.
6.4.3 Background illumination test
Target reflectivity: 95 % ± 5 %.
Temperature: 25 °C ± 3 °C.
Background illumination, case A: < 3 klx.
Background illumination, case B: > 30 klx.
Build up the measurement setup for the background illumination test (see Annex D for a selection of possible
setups). At the checkpoint CP01 or CP02 or CP03 (depending on which point fits better for the test under 6.4.4)
set the background illumination reflected by the target to an illuminance less than 3 klx. Then take and record
one measurement with the reference distance measurement system and 10 measurements with the device
under test. In the next step, set the background illumination reflected by the target to an illuminance higher
than 30 klx and take and record another 10 measurements with the device under test.
6.4.4 Temperature test
Target reflectivity: 95 % ± 5 %.
Background illumination: < 3 klx.
Temperature, case A: +5 °C ± 2 °C.
Temperature, case B: +25 °C ± 2 °C.
Temperature, case C: +45 °C ± 2 °C.
NOTE If the specified temperature range of the instrument is narrower than +5 °C to +45 °C, the test temperatures
for cases A to C may be adapted correspondingly (e.g. +5 °C, +20 °C, +35 °C).
Put the device under test into a temperature chamber and let the instruments adapt to the test temperature of
case A. Then take the instrument out of the chamber and immediately take and record 10 measurements at
the distance CP01 or CP02 or CP03 (same distance as under 6.4.3). Check that the background illumination
reflected by the target is below 3 klx. Repeat the same procedure for the remaining two test cases.
Alternatively, the measurements could be taken directly inside a temperature chamber if the instrument
is mounted on a reference distance measuring bar. In this case, the expansion of the reference distance
measuring bar over temperature has to be compensated in the calculations.
6.5 Calculation of deviations and uncertainty of measurement
6.5.1 Absolute distance test
Calculate the deviation ΔM of all measurements M from the corresponding reference value at each check point.
i i
ΔM = M - D (1)
REF
i i
Check, if all calculated deviations ΔM are inside the specified typical error tolerance field. Assuming a level of
i
confidence of 95 % for the typical tolerance definition, only 5 of the 100 measured points (10 at each check
point) are allowed to lie outside the specified typical error tolerance field.
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ISO 16331-1:2012(E)
At each check point calculate the experimental mean value of the absolute distance test D .
AD
N
1
D = M (2)
AD
∑ i
N
i=1
Calculate at each check point the deviation ΔD of the experimental mean value from the corresponding
AD
reference value.
ΔD D
= - D (3)
AD AD REF
At each check point calculate the corresponding experimental standard deviation s of the measured values
AD
and take it as the standard uncertainty u associated with the measured values.
AD
N
1
2
u = s = ()MD − (4)
AD AD
∑ i AD
N −1
i=1
6.5.2 Background illumination test
Calculate for both cases, low background illumination BG, low < 3 klx, and high background illumination BG,
high > 30 klx, and for each measurement M the deviation ΔM from the reference value.
i,X i,X
For each background illumination case calculate the experimental mean value D .
BG,X
N
1
D = M (5)
BG,X
iX,
∑
N
i=1
where X = background low, high.
Calculate the deviation ΔD of the experimental mean value from the corresponding reference value.
BG,X
ΔD = D - D (6)
BG,X BG,X BG,REF
where X = background low, high.
Calculate the additional deviation ΔD caused by the background illumination.
BG,Add
ΔD = ΔD - ΔD (7)
BG,Add BG,high BG,low
Calculate the corresponding experimental standard deviations for both cases of background illumination and
take them as the standard uncertainties associated with both cases.
N
1
2
u = s = ()MD − (8)
BG,X BG,X BG,X
∑ iX,
N −1
i=1
where X = background low, high.
Calculate the additional uncertainty u caused by the background illumination, assuming that
BG,Add
u > u .
BG,high BG,low
22
u = uu− (9)
BG,Add
BG,highBG,low
6.5.3 Temperature test
Calculate for each temperature case and for each measurement M the deviation ΔM from the
i,X i,X
corresponding reference value.
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ISO 16331-1:2012(E)
For each temperature case calculate the corresponding experimental mean value D .
T,X
N
1
D = M (10)
T,X
∑ i
N
i=1
where X = +5° C, +25 °C, +45 °C.
ΔD
Calculate the deviation of the experimental mean value from the corresponding reference value.
T,X
ΔD = D - D (11)
T,X T,X T,REF
where X = +5 °C, +25 °C, +45 °C.
Calculate the additional deviation ΔD and ΔD caused by the temperature influences at +5 °C
T05,Add T45,Add
and +45 °C in reference to the value calculated at 25 °C.
ΔD = ΔD - ΔD (12)
T05,Add T,5 °C T,25 °C
ΔD = ΔD - ΔD (13)
T45,Add T,45 °C T,25 °C
Calculate the corresponding experimental standard deviations for each temperature case and take them as the
standard uncertainties associated to the three cases.
N
1
2
u = ()MD − (14)
T,X TX,
iX,
∑
N −1
i=1
where X = 5 °C, 25 °C, 45 °C.
Calculate the additional uncertainties u caused by the temperature influences in reference to the value
T,Add
calculated at 25 °C. For calculation select the bigger value of the two possible values u and u . If
T,05 °C T,45 °C
u is the biggest of the three uncertainties then u = 0.
T,25 °C T,Add
2 2
u = uu− (15)
T,Add
TX,,TC25º
where X = 5 °C or 45 °C.
6.5.4 Combined deviation and combined uncertainty of measurements
Calculate the combined deviation range ΔD … ΔD of the experimental mean value (depending on
C,min C,max
temperature and background illumination) using the following formula.
ΔD = ΔD + max(ΔD ,0) + max(ΔD , ΔD , 0) (16)
C,max AD BG,Add T05,Add T45,Add
ΔD = ΔD + min(ΔD ,0) + min(ΔD , ΔD , 0) (17)
C,min AD BG,Add T05,Add T45,Add
NOTE For ΔD only positive contributions of ΔD and only the maximum positive contribution of ΔD
C,max BG,Add T05,Add
or ΔD are taken into account.
T45,Add
For ΔD only negative contributions of ΔD and only the most negative contribution of ΔD
C,min BG,Add T05,Add
or ΔD are taken into account.
T45,Add
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ISO 16331-1:2012(E)
Calculate the uncertainty u caused by the resolution of the display of the device under test.
DR
DR
u = (18)
DR
23
where DR = Display Resolution.
Calculate the combined uncertainty u of the measured values.
c
2 2 2 2 2 2 2
u = uu ++ uu++ uu ++ u (19)
c
REF,AD REF,BG REF,T DR AD BG,Add T,Addd
where
u is uncertainty of the reference system at the absolute distance test;
REF,AD
u is uncertainty of the reference system at the background illumination test;
REF,BG
u is uncertainty of the reference system at the temperature test;
REF,T
u is uncertainty of measurements at the absolute distance test of the check point that was used for
AD
the background illumination test and the temperature test;
u is additional uncertainty of measurement at the high background illumination case in relation to
BG,Add
the uncertainty of measurement at the low background illumination case;
u is additional uncertainty of measurement at higher or lower temperature in relation to the
T,Add
uncertainty of measurement at 25 °C.
6.5.5 Expanded uncertainty of measurements
Calculate the expanded uncertainty, U, for a level of confidence of 95 %.
U = k u (20)
c
where
k = 2.
6.6 Statement of test result
Give a statement on the test result as follows:
Deviation range of average values:
ΔD ΔD
… = ___ mm … ___ mm
C,min C,max
Expanded uncertainty of a single measurement: U = ___ mm
(level of confidence 95 %, k = 2,0)
Result: within/out of specification
NOTE Out of specification is given if ΔD - U < specified negative maximum error tolerance or if
C,min
ΔD + U > specified positive maximum error tolerance.
C,max
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ISO 16331-1:2012(E)
7 Test pr
...
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