ASTM E2938-15(2023)
(Test Method)Standard Test Method for Evaluating the Relative-Range Measurement Performance of 3D Imaging Systems in the Medium Range
Standard Test Method for Evaluating the Relative-Range Measurement Performance of 3D Imaging Systems in the Medium Range
SIGNIFICANCE AND USE
4.1 This standard provides a test method for obtaining the range error for medium-range 3D imaging systems. The results from this test method may be used to evaluate or to verify the range measurement performance of medium-range 3D imaging systems. The results from this test method may also be used to compare performance among different instruments.
4.2 The range performance of the IUT obtained by the application of this test method may be different from the range performance of the IUT under some real-world conditions. For example, object geometry, texture, temperature and reflectance as well as vibrations, particulate matter, thermal gradients, ambient lighting, and wind in the environment will affect the range performance.
4.3 The test may be carried out for instrument acceptance, warranty or contractual purposes by mutual agreement between the manufacturer and the user. The IUT is tested in accordance with manufacturer-supplied specifications, rated conditions, and technical documentation. This test may be repeated for any target 2 range within the manufacturer’s specifications and for any rated conditions.
4.4 For the purposes of understanding the behavior of the IUT and without warranty implications, this test may be modified as necessary to characterize the range measurement performance of the IUT outside the manufacturer’s rated conditions, but within the manufacturer’s limiting conditions.
4.5 The manufacturer may provide different values for the specifications for different sets of rated conditions, for example, better range measurement performance might be specified under a set of more restrictively rated environmental conditions. The user is advised that the IUT’s performance may differ significantly in other modes of operation or outside the rated conditions and should inquire with the manufacturer for specifications of the mode that best represents the planned usage. If a target other than that described in Section 7, or if procedures other...
SCOPE
1.1 This standard describes a quantitative test method for evaluating the range measurement performance of laser-based, scanning, time-of-flight, 3D imaging systems in the medium range. The term “medium range” refers to systems that are capable of operating within at least a portion of ranges from 2 to 150 m. The term “time-of-flight systems” includes phase-based, pulsed, and chirped systems. The word “standard” in this document refers to a documentary standard as per Terminology E284. This test method only applies to 3D imaging systems that are capable of producing a point cloud representation of a measured target.
1.1.1 As defined in Terminology E2544, a range is the distance measured from the origin of a 3D imaging system to a point in space. This range is often referred to as an absolute range. However, since the origin of many 3D imaging systems is either unknown or not readily measurable, a test method for absolute range performance is not feasible for these systems. Therefore, in this test method, the range is taken to be the distance between two points in space on a line that passes through the origin of the 3D imaging system. Although the error in the calculated distance between these two points is a relative-range error, in this test method when the term range error is used it refers to the relative-range error. This test method cannot be used to quantify the constant offset error component of the range error.
1.1.2 This test method recommends that the first point be at the manufacturer-specified target 1 range and requires that the second target be on the same side of the instrument under test (IUT) as the first target. Specification of target 1 range by the manufacturer minimizes the contribution to the relative range measurement error from the target 1 range measurement.
1.1.3 This test method may be used once to evaluate the IUT for a given set of conditions or it may be used multiple times to bett...
General Information
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: E2938 − 15 (Reapproved 2023)
Standard Test Method for
Evaluating the Relative-Range Measurement Performance of
3D Imaging Systems in the Medium Range
This standard is issued under the fixed designation E2938; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope conditions (for example, additional ranges, various
reflectances, environmental conditions).
1.1 This standard describes a quantitative test method for
evaluating the range measurement performance of laser-based,
1.2 The values stated in SI units are to be regarded as
scanning, time-of-flight, 3D imaging systems in the medium
standard. No other units of measurement are included in this
range. The term “medium range” refers to systems that are
standard. SI units are used for all calculations and results in this
capable of operating within at least a portion of ranges from 2
standard.
to 150 m. The term “time-of-flight systems” includes phase-
1.3 The method described in this standard is not intended to
based, pulsed, and chirped systems. The word “standard” in
replace more in-depth methods used for instrument calibration
this document refers to a documentary standard as per Termi-
or compensation, and specific measurement applications may
nology E284. This test method only applies to 3D imaging
require other tests and analyses.
systems that are capable of producing a point cloud represen-
tation of a measured target. 1.4 This standard does not purport to address all of the
1.1.1 As defined in Terminology E2544, a range is the safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
distance measured from the origin of a 3D imaging system to
a point in space. This range is often referred to as an absolute priate safety, health, and environmental practices and deter-
mine the applicability of regulatory limitations prior to use.
range. However, since the origin of many 3D imaging systems
is either unknown or not readily measurable, a test method for Some aspects of the safe use of 3D Imaging Systems are
discussed in Practice ASTM E2641.
absolute range performance is not feasible for these systems.
Therefore, in this test method, the range is taken to be the
1.5 This international standard was developed in accor-
distance between two points in space on a line that passes
dance with internationally recognized principles on standard-
through the origin of the 3D imaging system. Although the
ization established in the Decision on Principles for the
error in the calculated distance between these two points is a
Development of International Standards, Guides and Recom-
relative-range error, in this test method when the term range
mendations issued by the World Trade Organization Technical
error is used it refers to the relative-range error. This test
Barriers to Trade (TBT) Committee.
method cannot be used to quantify the constant offset error
component of the range error.
2. Referenced Documents
1.1.2 This test method recommends that the first point be at
2.1 ASTM Standards:
the manufacturer-specified target 1 range and requires that the
E284 Terminology of Appearance
second target be on the same side of the instrument under test
E1164 Practice for Obtaining Spectrometric Data for Object-
(IUT) as the first target. Specification of target 1 range by the
Color Evaluation
manufacturer minimizes the contribution to the relative range
E1331 Test Method for Reflectance Factor and Color by
measurement error from the target 1 range measurement.
Spectrophotometry Using Hemispherical Geometry
1.1.3 This test method may be used once to evaluate the IUT
E2544 Terminology for Three-Dimensional (3D) Imaging
for a given set of conditions or it may be used multiple times
Systems
to better assess the performance of the IUT for various
E2641 Practice for Best Practices for Safe Application of 3D
Imaging Technology
This test method is under the jurisdiction of ASTM Committee E57 on 3D
Imaging Systems and is the direct responsibility of Subcommittee E57.20 on
Terrestrial Stationary Systems. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved Dec. 1, 2023. Published December 2023. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 2015. Last previous edition approved in 2015 as E2938 – 15. DOI: Standards volume information, refer to the standard’s Document Summary page on
10.1520/E2938-15R23. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2938 − 15 (2023)
2.2 ASME Standards: 3.1.3 combined standard uncertainty, n—standard uncer-
ASME B89.1.9-2002 Gage Blocks tainty of the result of a measurement when that result is
ASME B89.4.19-2006 Performance Evaluation of Laser- obtained from the values of a number of other quantities, equal
Based Spherical Coordinate Measurement Systems to the positive square root of a sum of terms, the terms being
ASME B89.7.2-1999 Dimensional Measurement Planning the variances or covariances of these other quantities weighted
according to how the measurement result varies with changes
2.3 ISO Standards:
in these quantities. JCGM 100:2008 (GUM) – 2.3.4
ISO 14253-1:1998 Geometrical Product Specifications
(GPS)—Inspection by measurement of workpieces and
3.1.4 compensation, n—the process of determining system-
measuring equipment—Part 1: Decision rules for proving
atic errors in an instrument and then applying these values in an
conformance or non-conformance with specifications
error model that seeks to eliminate or minimize measurement
ISO 14253-2:1999 Geometrical Product Specifications
errors. ASME B89.4.19
(GPS)—Inspection by measurement of workpieces and
3.1.5 covariance—the covariance of two random variables
measuring equipment—Part 2: Guide to the estimation of
is a measure of their mutual dependence. JCGM 100:2008
uncertainty in GPS measurement, in calibration of mea-
(GUM) – C.3.4
suring equipment and in product verification
3.1.6 coverage factor, n—numerical factor used as a multi-
2.4 JCGM Standards:
plier of the combined standard uncertainty in order to obtain an
JCGM 200:2012 International vocabulary of metrology—
expanded uncertainty.
Basic and general concepts and associated terms (VIM),
3.1.6.1 Discussion—A coverage factor, k, is typically in the
3rd edition
range 2 to 3. JCGM 100:2008 (GUM) 2.3.6
JCGM 100:2008 Evaluation of measurement data—Guide to
3.1.7 diffuse reflectance factor, R , n—the ratio of the flux
the expression of uncertainty in measurement (GUM), 1st
d
reflected at all angles within the hemisphere bounded by the
edition
plane of measurement except in the direction of the specular
3. Terminology reflection angle, to the flux reflected from the perfect reflecting
diffuser under the same geometric and spectral conditions of
3.1 Definitions:
measurement. E284 Section 3.1
3.1.1 3D imaging system, n—a non-contact measurement
3.1.7.1 Discussion—The size of the specular reflection
instrument used to produce a 3D representation (for example,
angle depends on the instrument and the measurement condi-
a point cloud) of an object or a site. E2544
tions used. For its precise definition the make and model of the
3.1.1.1 Discussion—Some examples of a 3D imaging sys-
instrument or the aperture angle or aperture solid angle of the
tem are laser scanners (also known as LADARs or LIDARs or
specularly reflected beam should be specified.
laser radars), optical range cameras (also known as flash
3.1.8 documentary standard, n—document, arrived at by
LIDARs or 3D range cameras), triangulation-based systems
such as those using pattern projectors or lasers, and other open consensus procedures, specifying necessary details of a
systems based on interferometry. method of measurement, definitions of terms, or other practical
3.1.1.2 Discussion—In general, the information gathered by matters to be standardized. E284
a 3D imaging system is a collection of n-tuples, where each
3.1.9 expanded test uncertainty, n—product of a combined
n-tuple can include but is not limited to spherical or Cartesian
standard measurement uncertainty and a factor larger than the
coordinates, return signal strength, color, time stamp, identifier,
number one. JCGM 200:2012 (VIM) – 2.35
polarization, and multiple range returns.
3.1.10 flatness, n—the minimum distance between two par-
3.1.1.3 Discussion—3D imaging systems are used to mea-
allel planes between which all points of the measuring face lie.
sure from relatively small scale objects (for example, coin,
ASME B89.1.9 – 3.5
statue, manufactured part, human body) to larger scale objects
3.1.11 limiting conditions, n—the manufacturer’s specified
or sites (for example, terrain features, buildings, bridges, dams,
limits on the environmental, utility, and other conditions within
towns, archeological sites).
which an instrument may be operated safely and without
3.1.2 calibration, n—operation that, under specified
damage. ASME B89.4.19
conditions, in a first step, establishes a relation between the
3.1.11.1 Discussion—The manufacturer’s performance
quantity values with measurement uncertainties provided by
specifications are not assured over the limiting conditions.
measurement standards and corresponding indications with
3.1.12 maximum permissible error (MPE), n—extreme
associated measurement uncertainties and, in a second step,
value of measurement error, with respect to a known reference
uses this information to establish a relation for obtaining a
quantity value, permitted by specifications or regulations for a
measurement result from an indication. JCGM 200:2012
given measurement, measuring instrument, or measuring
(VIM) – 2.39
system. JCGM 200:2012 (VIM) – 4.26
3.1.12.1 Discussion—Usually, the term “maximum permis-
Available from American Society of Mechanical Engineers (ASME), ASME
sible errors” or “limits of error” is used where there are two
International Headquarters, Two Park Ave., New York, NY 10016-5990, http://
extreme values.
www.asme.org.
3.1.12.2 Discussion—The term “tolerance” should not be
Available from American National Standards Institute (ANSI), 25 W. 43rd St.,
4th Floor, New York, NY 10036, http://www.ansi.org. used to designate ‘maximum permissible error’.
E2938 − 15 (2023)
3.1.13 measurand, n—quantity intended to be measured. 3.1.16 measurement uncertainty, n—non-negative param-
JCGM 200:2012 (VIM) – 2.3 eter characterizing the dispersion of the quantity values being
attributed to a measurand, based on the information used.
3.1.13.1 Discussion—The specification of a measurand re-
JCGM 200:2012 (VIM) – 2.26
quires knowledge of the kind of quantity, description of the
3.1.16.1 Discussion—Measurement uncertainty includes
state of the phenomenon, body, or substance carrying the
components arising from systematic effects, such as compo-
quantity, including any relevant component, and the chemical
nents associated with corrections and the assigned quantity
entities involved.
values of measurement standards, as well as the definitional
3.1.13.2 Discussion—In the second edition of the VIM and
uncertainty. Sometimes estimated systematic effects are not
in IEC 60050-300:2001, the measurand is defined as the
corrected for but, instead, associated measurement uncertainty
‘quantity subject to measurement’.
components are incorporated.
3.1.13.3 Discussion—The measurement, including the mea-
3.1.16.2 Discussion—The parameter may be, for example, a
suring system and the conditions under which the measurement
standard deviation called standard measurement uncertainty (or
is carried out, might change the phenomenon, body, or sub-
a specified multiple of it), or the half-width of an interval,
stance such that the quantity being measured may differ from
having a stated coverage probability.
the measurand as defined. In this case, adequate correction is
3.1.16.3 Discussion—Measurement uncertainty comprises,
necessary.
in general, many components. Some of these may be evaluated
Example 1—The potential difference between the termi-
by Type A evaluation of measurement uncertainty from the
nals of a battery may decrease when using a voltmeter with
statistical distribution of the quantity values from series of
a significant internal conductance to perform the measure-
measurements and can be characterized by standard deviations.
ment. The open-circuit potential difference can be calculated
The other components, which may be evaluated by Type B
from the internal resistances of the battery and the voltmeter.
evaluation of measurement uncertainty, can also be character-
Example 2—The length of a steel rod in equilibrium with
ized by standard deviations, evaluated from probability density
the ambient Celsius temperature of 23°C will be different
functions based on experience or other information.
from the length at the specified temperature of 20°C, which
3.1.16.4 Discussion—In general, for a given set of
is the measurand. In this case, a correction is necessary.
information, it is understood that the measurement uncertainty
3.1.13.4 Discussion—In chemistry, “analyte”, or the name
is associated with a stated quantity value attributed to the
of a substance or compound, are terms sometimes used for
measurand. A modification of this value results in a modifica-
‘measurand’. This usage is erroneous because these terms do
tion of the associated uncertainty.
not refer to quantities.
3.1.17 point cloud, n—a collection of data points in 3D
3.1.14 measurement accuracy, n—closeness of agreement
space (frequently in the hundreds of thousands), for example as
between a measured quantity value and a true quantity value of
obtained using a 3D imaging system. E2544
a measurand. JCGM 200:2012 (VIM) – 2.13
3.1.17.1 Discussion—The distance between points is gener-
3.1.14.1 Discussion—The concept ‘measurement accuracy’
ally non-uniform and hence all three coordinates (Cartesian or
is not a quantity and is not given a numerical quantity value. A
spherical) for each point must be specifically encoded.
measurement is said to be more accurate when it offers a
3.1.18 range, n—the distance, in units of length, between a
smaller measurement error.
point in space and an origin fixed to the 3D imaging system
3.1.14.2 Discussion—The term “measurement accurac
...
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