ASTM F792-17e1

Standard Practice for Evaluating the Imaging Performance of Security X-Ray Systems

SCOPE
1.1 This practice applies to all X-ray-based screening systems with tunnel apertures up to 1 m wide × 1 m high, whether they are conventional X-ray systems or explosives detection systems, that provide a projection or projection/scatter image.  
1.2 This practice applies to X-ray systems used for the screening for prohibited items such as weapons, explosives, and explosive devices in baggage, packages, cargo, or mail.  
1.3 This practice establishes quantitative and qualitative methods for evaluating the systems. This practice does not establish minimum performance requirements for any particular application.  
1.4 This practice relies upon the use of three different standard test objects: ASTM X-ray test object – HP, for evaluating human perception based performance parameters; ASTM X-ray test object – RT, for routine testing to assess operation; and ASTM X-ray test object – OE, for objective evaluation and scoring of the technical capability of the system. The specific test objects are subsequently described and referred to in this practice as the HP test object, RT test object, and OE test object.  
1.4.1 Part RT—This part considers only the methods for routine and periodic verification of system operation and function, and therefore requires use of ASTM X-ray test object – RT.  
1.4.2 Part HP—This part considers only the methods for, and use of, the ASTM X-ray test object – HP.  
1.4.3 Part OE—This part considers only the methods for objective evaluation of the technical capabilities of a system, and therefore requires use of the ASTM X-ray test object – OE.  
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.  
1.6 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.7 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.

General Information

• Status: Published
• Publication Date: 31-Mar-2017
• ICS: 13.310 - Protection against crime
• Technical Committee: F12 - Security Systems and Equipment
• Drafting Committee: F12.60 - Controlled Access Security, Search, and Screening Equipment

Relations

• Replaces: ASTM F792-17 - Standard Practice for Evaluating the Imaging Performance of Security X-Ray Systems
• Effective Date: 01-Apr-2017
• Refers: ASTM B258-18 - Standard Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors
• Effective Date: 01-Oct-2018
• Refers: ASTM D6100-17 - Standard Specification for Extruded, Compression Molded and Injection Molded Polyoxymethylene Shapes (POM)
• Effective Date: 01-Dec-2017
• Refers: ASTM D6100-14 - Standard Specification for Extruded, Compression Molded and Injection Molded Polyoxymethylene Shapes (POM)
• Effective Date: 01-May-2014
• Refers: ASTM D6100-11 - Standard Specification for Extruded, Compression Molded and Injection Molded Polyoxymethylene Shapes (POM)
• Effective Date: 01-Apr-2011
• Refers: ASTM B258-02(2008) - Standard Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors
• Effective Date: 01-Sep-2008
• Refers: ASTM D6100-05 - Standard Specification for Extruded, Compression Molded and Injection Molded Acetal Shapes (POM)
• Effective Date: 15-Jul-2005
• Refers: ASTM D6100-03 - Standard Specification for Extruded, Compression Molded and Injection Molded Acetal Shapes (POM)
• Effective Date: 10-Jul-2003
• Refers: ASTM B258-02 - Standard Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors
• Effective Date: 10-Apr-2002
• Refers: ASTM B258-01 - Standard Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors
• Effective Date: 10-Apr-2002
• Refers: ASTM D6100-97 - Standard Specification for Extruded, Compression Molded and Injection Molded Acetal Shapes (POM)
• Effective Date: 10-Apr-1997

Overview

ASTM F792-17e1: Standard Practice for Evaluating the Imaging Performance of Security X-Ray Systems provides a comprehensive methodology for objectively assessing the imaging performance of X-ray-based screening systems. This international ASTM standard applies to X-ray screening systems with tunnel apertures up to 1 meter wide by 1 meter high, including both conventional security X-ray and explosives detection systems. Its primary focus is to ensure consistent, reliable evaluation of image quality for identifying prohibited items such as weapons, explosives, and hazardous devices in baggage, packages, cargo, and mail.

This practice outlines both quantitative and qualitative evaluation methods, but does not set minimum acceptable performance requirements. Instead, it relies on the use of three standardized test objects to systematically measure and monitor key imaging metrics relevant to operator performance and system capability.

Key Topics

• Applicability: Targets all tunnel-type X-ray screening equipment used for security and contraband detection.
• Test Objects: Utilizes three specific, standardized test pieces:
  • HP (Human Perception): For evaluating operator-centric imaging metrics
  • RT (Routine Testing): For periodic operational verification
  • OE (Objective Evaluation): For technical and objective image quality scoring
• Evaluation Metrics: Covers a wide range of image quality indicators, including:
  • Wire display capability
  • Useful penetration through blockages
  • Spatial resolution for closely spaced items
  • Simple and complex penetration (such as through layered or organic materials)
  • Material discrimination and classification, including differentiating between metals and organics
  • Dynamic range and noise metrics for system consistency
  • Modulation Transfer Function (MTF) and Noise Equivalent Quanta (NEQ) for objective system assessment
• SI Units Standardization: All measurements and reporting in SI units only
• Operator and System Performance: Distinguishes between operator performance (human perception) and objective technical system performance
• Routine and Periodic Assessment: Enables ongoing image quality tracking and system performance trend analysis

Applications

The practice outlined in ASTM F792-17e1 is essential for a wide range of industries and organizations, including:

• Aviation and Transportation Security: Used in airport screening of baggage and cargo to detect prohibited and dangerous items
• Mail and Parcel Inspection: Deployed in government, corporate, and correctional facilities to intercept contraband or hazardous items
• Customs and Border Protection: Supports reliable screening of commercial shipments and cross-border parcels
• Critical Infrastructure Protection: Employed at nuclear facilities, government offices, and high-security environments for access control and threat detection

Key practical benefits include:

• Verification of X-ray system performance against manufacturer specifications or over time
• Early detection of image quality degradation or malfunctions
• Optimized operator performance through consistent, high-quality imaging
• Support for compliance with regulatory requirements and best practices in security screening

Related Standards

Organizations implementing ASTM F792-17e1 may also consider the following related standards:

• ASTM B258: Specification for Standard Nominal Diameters and Cross-Sectional Areas of AWG Sizes of Solid Round Wires Used as Electrical Conductors
• IEC 60317-1: Specification for particular types of winding wires - Polyvinyl acetal enameled round copper wire
• ANSI/NEMA MW 1000: American National Standard for Magnet Wire
• ISO 12233: Photography - Electronic still-picture cameras - Resolution measurements

These referenced documents support the standard's technical definitions or the materials used in constructing the standard test objects for X-ray imaging systems.

In summary, ASTM F792-17e1 delivers a robust, internationally recognized framework for evaluating security X-ray system imaging performance. It promotes reliable operation, fosters regulatory compliance, and enhances the detection of threats across diverse security and screening environments.

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.
´1
Designation: F792 − 17
Standard Practice for
Evaluating the Imaging Performance of Security X-Ray
Systems
ThisstandardisissuedunderthefixeddesignationF792;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
ε NOTE—Editorially corrected adjunct number in 2.2 in September 2017.
1. Scope 1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This practice applies to all X-ray-based screening sys-
responsibility of the user of this standard to establish appro-
temswithtunnelaperturesupto1mwide×1mhigh,whether
priate safety, health and environmental practices and deter-
they are conventional X-ray systems or explosives detection
mine the applicability of regulatory limitations prior to use.
systems, that provide a projection or projection/scatter image.
1.7 This international standard was developed in accor-
1.2 This practice applies to X-ray systems used for the
dance with internationally recognized principles on standard-
screening for prohibited items such as weapons, explosives,
ization established in the Decision on Principles for the
and explosive devices in baggage, packages, cargo, or mail.
Development of International Standards, Guides and Recom-
mendations issued by the World Trade Organization Technical
1.3 This practice establishes quantitative and qualitative
methods for evaluating the systems. This practice does not Barriers to Trade (TBT) Committee.
establish minimum performance requirements for any particu-
2. Referenced Documents
lar application.
2.1 ASTM Standards:
1.4 This practice relies upon the use of three different
B258Specification for Standard Nominal Diameters and
standard test objects:ASTM X-ray test object–HP, for evalu-
Cross-Sectional Areas of AWG Sizes of Solid Round
ating human perception based performance parameters;ASTM
Wires Used as Electrical Conductors
X-ray test object–RT, for routine testing to assess operation;
D6100SpecificationforExtruded,CompressionMoldedand
andASTMX-raytestobject–OE,forobjectiveevaluationand
Injection Molded Polyoxymethylene Shapes (POM)
scoring of the technical capability of the system. The specific
test objects are subsequently described and referred to in this 2.2 ASTM Adjuncts:
practice as the HP test object, RT test object, and OE test Adjunct to F0792 Drawings for Test Piece
object.
2.3 Other Documents:
1.4.1 Part RT—This part considers only the methods for
IEC 60317-1:2010-03Specification for Particular Types of
routine and periodic verification of system operation and
Winding Wires–Part 1: Polyvinyl Acetal Enamelled
function, and therefore requires use of ASTM X-ray test
Round Copper Wire, Class 105
object–RT.
ANSI/NEMAMW 1000-2014American National Standard,
1.4.2 Part HP—This part considers only the methods for,
Magnet Wire (MW 80-C)
and use of, the ASTM X-ray test object–HP.
ISO 12233-2000 Photography – Electronic Still-Picture
1.4.3 Part OE—This part considers only the methods for
Cameras–ResolutionMeasurements,Section6.3andAn-
objective evaluation of the technical capabilities of a system,
nex C
andthereforerequiresuseoftheASTMX-raytestobject–OE.
1.5 The values stated in SI units are to be regarded as
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
standard. No other units of measurement are included in this
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
standard.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
Available from ASTM International Headquarters. Order Adjunct No.
This practice is under the jurisdiction of ASTM Committee F12 on Security ADJF079217-E-PDF. Original adjunct produced in 2017.
Systems and Equipment and is the direct responsibility of Subcommittee F12.60 on Available from International Electrotechnical Commission (IEC), 3, rue de
Controlled Access Security, Search, and Screening Equipment. Varembé, 1st Floor, P.O. Box 131, CH-1211, Geneva 20, Switzerland, http://
Current edition approved April 1, 2017. Published August 2017. Originally www.iec.ch.
approved in 1982. Last previous edition approved in 2008 as F792–08 which was Available fromAmerican National Standards Institute (ANSI), 25 W. 43rd St.,
withdrawn January 2017 and reinstated inApril 2017. DOI: 10.1520/F0792-17E01. 4th Floor, New York, NY 10036, http://www.ansi.org.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
´1
F792 − 17
3. Terminology 3.1.6.8 test 8: materials classification—the ability of an
X-raysystemtodisplayimagesthatcanbeusedbyanoperator
3.1 Definitions of Terms Specific to This Standard:
to consistently identify a particular material over a range of
3.1.1 blocking material—a thickness of material used to
different thicknesses.
obscuretheviewofanobjectinanX-rayimagebyattenuating
3.1.6.9 test 9: organic differentiation—the ability of an
the X-ray beam used to form the image.
X-raysystemtodisplayimagesthatcanbeusedbyanoperator
3.1.2 boundary signal-to-noise ratio (BSNR)—a metric for
to differentiate between organic materials of different effective
measuring the detectability of a boundary; the BSNR is
atomic numbers.
computed by comparing the average pixel value between
3.1.7 image quality metric (Part OE)—aquantitativeassess-
regions of interest on either side of the boundary; the signifi-
ment of a capability of an imaging system; six image quality
cance of the difference in the pixel value is determined by
metrics are defined in this part of the practice along with the
measuring the consistency for repeated measurements for
standard test pieces and methods necessary for their measure-
different images; see A3.1 for a complete technical definition.
ment.
3.1.3 contrast sensitivity—a measure of the minimum
3.1.7.1 test 1: steel differentiation—the ability of an X-ray
change in an object that produces a perceptible brightness
systemtoprovideanimagethatcanbeusedtodetect,usingan
change in the image on a display.
objective algorithm, boundaries between different thicknesses
of steel.
3.1.4 effective atomic number (Z )—theatomicnumberofa
eff
3.1.7.2 test 2: useful penetration—the ability of an X-ray
single hypothetical element that, for a particular x-ray
systemtoproduceanimagethatallowsforthedetection,byan
spectrum, would exhibit essentially identical X-ray attenuation
operator or algorithm, of wires that are hidden by different
characteristics as the material under consideration.
thicknesses of blocking material.
3.1.5 hue—a property of a color that reflects the degree to
3.1.7.3 test 3: organic boundary signal-to-noise ratio—a
which it can be classified as red, green, and blue; this property
measure of the ability of an X-ray system to detect thickness
can be considered independently of the lightness of the color,
changes in thin pieces of low atomic-number material.
for example, a red color and a pink color may have the same
3.1.7.4 test 4: spatial resolution—the ability of an X-ray
hue but different lightness and saturation.
system to display closely spaced, high-contrast items as sepa-
3.1.6 image quality metric (Part HP)—aquantitativeassess-
rate.
ment of a capability of an imaging system; nine image quality
3.1.7.5 test 5: dynamic range—the ratio between the largest
metrics are defined in this practice along with the standard test
and smallest usable grayscale values.
object and methods necessary for their measurement.
3.1.7.6 test 6: noise equivalent quanta (NEQ)—a spatial-
3.1.6.1 test 1: wire display—the ability of an X-ray system
frequency-dependent measure of the detection ability of an
to display images that can be used by an operator to identify
imaging system that is quantified in terms of the number of
metal wires.
photons, or quanta, that would be required to achieve the same
3.1.6.2 test 2: useful penetration—the ability of an X-ray detection ability for an ideal imaging system; the NEQ is
systemtoproduceanimagethatallowsforthedetection,byan
computed from measurements of the modulation transfer
operator or algorithm, of wires that are hidden by different function, the noise power spectrum, and the average pixel
thicknesses of blocking material. value of uniformly illuminated noise images.
3.1.8 modulation transfer function (MTF)—a spatial-
3.1.6.3 test 3: spatial resolution—the ability of an X-ray
frequency-dependent measure of contrast reduction used to
system to display closely spaced, high-contrast items as sepa-
characterizeanimagingsystem’sspatialresolution,thatishere
rate.
derived from the system’s edge-spread function.
3.1.6.4 test 4: simple penetration—the ability of an X-ray
3.1.9 noise power spectrum (NPS)—a spatial-frequency-
system to display images that can be used by an operator to
dependentfunctionthatcharacterizesthenoisepropertiesofan
identify lead numerals that would otherwise be hidden by steel
image, computed using the Fourier transform of uniformly
blocking material.
illuminated noise images.
3.1.6.5 test 5: thin organic imaging—the ability of an X-ray
3.1.10 Nyquist frequency—a frequency that is half the spa-
system to display images that can be used by an operator to
tial sampling frequency; in units of cycles per pixel, it always
identify thin pieces of organic material.
has a value of 0.5 but in this practice it should be expressed in
units of cycles per mm.
3.1.6.6 test 6: steel contrast sensitivity—the ability of an
X-raysystemtodisplayimagesthatcanbeusedbyanoperator
3.1.11 operator—the person operating the X-ray imaging
to identify shallow circular recesses in steel.
device.
3.1.6.7 test 7: materials discrimination—the ability of an
3.1.12 region of interest (ROI)—an area on the image of a
X-raysystemtodisplayimagesthatcanbeusedbyanoperator specified size and position; an ROI is usually selected in order
to discriminate between materials with different effective
to compute some statistical quantity over the pixels it contains
atomic numbers. (for example, the mean value or the standard deviation).
´1
F792 − 17
3.1.13 test image—a grayscale digital X-ray image of the Mechanical drawings for the test object that shall be used with
ASTM X-ray test object-OE to which the objective algorithms this practice are given in A1.1.1.
are applied.
4.2.2 The RT is fragile because of the polycarbonate sub-
strate on which the wires and step wedge are mounted.
3.1.14 test object—the physical object required to test a
Consequently, the RT shall be contained and scanned within a
system using this practice; the test object includes various test
case with the following specifications:
pieces, the mounting board, a protective case, padding
material, and fasteners.
Interior dimensions: at least (19.5 cm × 12.5 cm×5cm) ±0.5 cm
Wall, top and bottom (largest surfaces of case):
3.1.15 test piece—a part of the test object that is used to
Material: ABS plastic
measure the value of an image quality metric in this practice; Thickness: between 1.5 mm and 3 mm
Construction: single piece of ABS Plastic. No joints, fasteners, or foreign
for example, the POM step wedge used to evaluate the thin
objects, other than fill material, shall be between the case and the
organic imaging test (test 5 of part OE).
RT test object. These surfaces shall be nominally flat (this is, exhibit a
radius of curvature greater than about 10 m) over a nominally central area
3.1.16 useful penetration—the ability of an X-ray system to
of at least 17 cm × 11 cm.
produce an image that allows for the detection, by an operator
Fill:
orobjectivealgorithm,ofwiresthatwouldotherwisebehidden Material: polyethylene foam
Thickness: sufficient to hold RT firmly in place and nominally centered within
by different thickness of blocking material.
the case.
4.3 Test Procedures:
4. Part RT
4.3.1 Obtain an image of the test object in its case using the
4.1 Significance and Use:
standard operating procedure (for example, by placing the test
4.1.1 This practice applies to and establishes methods to
object on the conveyor belt so that it is run through the
measure the imaging performance of X-ray systems used for
scanning area). The location and orientation of the RT test
security screening. Such systems are typically used to screen
object on the conveyor belt of the cabinet X-ray system is not
for prohibited items such as weapons, explosives, and explo-
critical. However, to maximize the accuracy and usefulness of
sive devices in baggage, packages, cargo, or mail.
imageperformancetracking,thepositionandorientationofthe
4.1.2 The most significant attributes of this practice are the
RT test object should be nominally the same each time it is
design of test object and standard methods for determining the
used for this purpose, and this orientation and location shall be
performance levels of the system.
recorded. More than one location and orientation may be used,
4.1.3 In screening objects with X-ray systems, still images
in which case each orientation and location pairing of the RT
are the primary inputs provided to operators. It is assumed that
shall be recorded. Any image enhancement features provided
the better the quality of these images, the better will be the
by the cabinet X-ray system may be used, and the setting for
potential performance of the operator.
these features shall be recorded.
4.1.4 This practice is intended to provide the ability to
routinely assess the performance of a cabinet X-ray system.
4.4 Evaluation Considerations:
This routine assessment can be used to ensure that: the cabinet
4.4.1 General—Use of this practice does not guarantee that
X-ray system is operational; the imaging performance nomi-
the X-ray system is operating properly. It is not intended to
nally meets expectation; and any changes in imaging perfor-
replace the X-ray system’s diagnostics. If problems are expe-
mance are tracked.
rienced with the X-ray system they must be resolved prior to
4.1.5 Thispracticeisnotintendedtobeusedasthebasisfor
operation.
system qualification or validation.
4.4.2 Training Requirements—To effectively conduct the
4.2 Test Object: evaluation of an X-ray system, it is recommended that the
4.2.1 Images of the RT test object are shown in Fig. 1. evaluator be trained to operate the X-ray system under test.
FIG. 1 An Image of the Front and Back of the Practice F792 – RT Test Object
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F792 − 17
4.4.3 Result Interpretation and Significance—A wire not particularoperatororoperators.Differentoperatorsmayobtain
under aluminum is considered to be seen if more than half of different results for the same system.
it is visible in the X-ray image. A wire under a particular step
5.1.5 Tests 7, 8, and 9 only apply to systems that have
is considered to be seen if, in the X-ray image, more than half
materials discrimination capabilities and use image hue to
of it is visible under that step.
represent materials information (that is, effective atomic num-
4.4.4 Log Sheet Use—Table 1 is the log sheet that shall be
ber).
completed by the evaluator each time an evaluation is con-
5.2 Test Object:
ducted. Results shall be recorded on the log sheet for every
5.2.1 The following describes the ASTM X-ray test ob-
location and orientation under test. Mark a U in the box
ject–HP (shown in Fig. 2) to be used throughout the test
corresponding to each segment of wire that can be seen. The
procedures to determine the performance levels of a system.A
log sheet shall serve as a record of the results and observations
drawingindexforthetestobjectisprovidedinTable2.Copies
regardingthetests.Logsheetsshallberetainedinthesystems’
of the mechanical drawings listed in Table 2 are provided in
log book for a set period, to be determined by the security
A2.2.
administrator, so that results of tests can be compared to those
of previous tests for that system. 5.2.2 Thetestpiecesandmountingboardarefragile,sothey
should be contained and scanned within a protective case with
5. Part HP
the following specification:
Interior dimensions: at least (45 cm by 28 cm by 12 cm)
5.1 Significance and Use:
Wall, top and bottom (largest surfaces of case):
5.1.1 This practice applies to and establishes methods to
Material: ABS plastic
measure the imaging performance of X-ray systems used for
Thickness: 3 mm ± 0.2 mm (in the regions directly above and below the test
security screening. Such systems are typically used to screen pieces).
Construction: single piece of molded ABS black plastic. No joints, fasteners
for prohibited items such as weapons, explosives, and explo-
or foreign objects, other than fill material, shall be between the case
sive devices in baggage, packages, cargo, or mail.
and the test pieces along the paths of the X rays that form the image. These
5.1.2 The most significant attributes of this practice are the surfaces shall be nominally flat (that is, exhibit a radius of curvature greater
than about 10 m) over nominally a central area of at least 41.5 cm × 25 cm.
design of test object and standard methods for determining the
Fill: polyethylene foam with a thickness sufficient to hold the mounting board
performance levels of the system.
and test pieces in place within the case. The density of the foam should
be less than 0.03 g/cm . No foam should be present in the region directly
5.1.3 In screening objects with X-ray systems, still images
above the test piece for tests 7 and 8.
are the primary inputs provided to operators. It is assumed that
the better the quality of these images, the better will be the 5.2.3 Test 1–Wire Display—TodeterminehowwellanX-ray
potential performance of the operator. system displays wires, the test object incorporates a set of
5.1.4 The results produced by this practice reflect the unobstructedwires.ThecopperwiresofAWGsizes24,30,34,
performance of an X-ray system under the control of a 38,and42arelaidoutonthetestobjectinasinusoidalpattern.
TABLE 1 Imaging Performance Data
NOTE 1—This table is a log sheet for recording the results of testing a cabinet X-ray system using the RT test object. Dimensional details of the wire
gauges are given in Specification B258.
´1
F792 − 17
The test pieces for all nine tests are labelled on the test object and are described in more detail in subsequent sections.
FIG. 2 An Image of the Practice F792 – HP Test Object
TABLE 2 Test Object Drawing Index
NOTE 1—See A2.2 for the complete set of drawings.
Item Number Description Test Part Number Drawing
ASTM F792 – HP X-Ray Test Object ASSY 1 1 of 20
Mounting Board BOARD 2 of 20
1A Tests 1 and 2 Assembly Tests 1 and 2 T1A-ASSY 3 of 20
1B Tests 1 and 2 Step Wedge Tests 1 and 2 T1B-WEDGE 4 of 20
1C Tests 1 and 2 Wire Holder Tests 1 and 2 T1C-HOLDER 5 of 20
3 Test 3 Pattern Test 3 T3–PATTERN 6 of 20
4 Test 4 Steel Step Wedge Test 4 T4–WEDGE 7 of 20
5 Test 5 POM Step Wedge Test 5 T5–WEDGE 8 of 20
6A Test 6 Steel Pattern Sheet Test 6 T6A-PATTERN 9 of 20
6B Test 6 Steel Step Wedge Test 6 T6B-WEDGE 10 of 20
7A Tests 7 and 8 Upper Assembly Tests 7 and 8 T7A-ASSY1 11 of 20
7B Tests 7 and 8 Steel Grid Tests 7 and 8 T7B-GRID 12 of 20
7C Tests 7 and 8 Thick POM Wedge Tests 7 and 8 T7C-THICK 13 of 20
7D Tests 7 and 8 Medium POM Wedge Tests 7 and 8 T7D-MEDIUM 14 of 20
7E Tests 7 and 8 Thin POM Wedge Tests 7 and 8 T7E-THIN 15 of 20
7F Tests 7 and 8 Lower Assembly Tests 7 and 8 T7F-ASSY2 16 of 20
7G Tests 7 and 8 Lower Base Tests 7 and 8 T7G-BASE 17 of 20
9A Test 9 Assembly Test 9 T9A-ASSY 18 of 20
9B Test 9 Organic Blocks Test 9 T9B-BLOCK 19 of 20
9C Test 9 Grid Test 9 T9C-GRID 20 of 20
ThediametersofthewiresofAWGsizes24,30,34,38,and42 of narrowly spaced line-pair gauges. Four pairs of horizontal
are 0.511 mm, 0.254 mm, 0.160 mm, 0.102 mm, and 0.064 and vertical line-pair gauges are present on the test piece with
mm, respectively. spacings of 2 mm, 1.5 mm, 1.0 mm, and 0.5 mm.
5.2.4 Test 2–Useful Penetration—To determine the useful 5.2.6 Test 4–Simple Penetration—To determine the simple
penetration of an X-ray system, the test object incorporates a penetration of an X-ray system, the test object incorporates
set of five wires placed under aluminum steps that vary in lead numerals placed on top of steel that varies in thickness.
thickness. The gauge of these wires and the thickness of the The thicknesses of the steel steps are 16 mm, 20 mm, 24 mm,
aluminumprovidessufficientrangetocharacterizethesystem’s 28 mm, 32 mm, 36 mm, and 40 mm.
useful penetration. The copper wires ofAWG sizes 24, 30, 34, 5.2.7 Test 5–Thin Organic Imaging—To determine the thin
38, and 42 are laid out on the test object in a sinusoidal pattern organic imaging capability of an X-ray system, the test object
under aluminum steps with thicknesses of 4 mm, 8 mm, 12 incorporates a set of holes machined into plastic of various
mm, 16 mm, and 20 mm. thicknesses.Theplasticstepshavethicknessesof0.25mm,0.5
5.2.5 Test 3–Spatial Resolution—To determine the spatial mm, 1.0 mm, 2 mm, and 5 mm and each step has holes of
resolutionofanX-raysystem,thetestobjectincorporatesaset diameters 2 mm, 5 mm, and 10 mm cut through them.
´1
F792 − 17
5.2.8 Test 6–Steel Contrast Sensitivity—To determine the mended operating range. The results of the tests are to be
steel contrast sensitivity of an X-ray system, the test object retained as part of the X-ray system’s performance/testing
incorporates a set of circular holes behind steel of various record.
thicknesses.Thesteelstepshavethicknessesof0.5mm,1mm,
5.3.2 Test 1–Wire Display—Using the image obtained in
2mm,and5mm,andeachstephasholes,allofdepth0.1mm, 5.3.1.2, record the Test 1 wires that can be seen on the display
with diameters of 2 mm, 5 mm, and 10 mm.
(that is, the wires not under the aluminum step wedge).Awire
isconsideredtobevisibleifmorethanhalfofitslengthcanbe
5.2.9 Test 7–Materials Discrimination—To determine the
seen. Record aU in the box on the log sheet next to each wire
materialsdiscriminationcapabilityoftheX-raysystem,thetest
that is visible.
object incorporates a grid of square attenuators. The effective
atomic number and attenuation of each attenuator is controlled 5.3.3 Test 2–Useful Penetration—Using the image obtained
in 5.3.1.2, record all the Test 2 wires (that is, the wires under
by varying the amount of steel and plastic in each. The
the aluminum step wedge) that can be seen on the displayed
effective atomic number of the attenuators varies in the
image.Awireisconsideredtobevisibleunderaparticularstep
horizontal axis and the total attenuation varies in the vertical
if more than half of its length under that step can be seen.
axis, as viewed in Fig. 2. Details regarding the amount of steel
Record aU in the box on the log sheet along each segment of
and plastic in each attenuator in the grid are provided in the
wire that is visible under the step wedge.
mechanical drawings of the test object in A2.2.
5.3.4 Test 3–Spatial Resolution—Using the image obtained
5.2.10 Test 8–Materials Classification—To determine if the
in 5.3.1.2, record which sets of vertical and horizontal slots in
X-ray system consistently identifies a given material over a
the displayed image of the Test 3 test piece can be resolved.
range of thicknesses, the same test piece is used as for Test 7.
Vertical and horizontal slots are considered to be resolved if
5.2.11 Test 9–Organic Differentiation—This practice is in-
and only if all four slots can be seen and there is visible
tended for use at both the point of manufacture and where the
separation between each slot. Record aU in the log sheet box
system is operated. The latter includes locations such as
above each set of vertical and horizontal slots that is resolved.
securitycheckpointsoftransportationterminals,nuclearpower
5.3.5 Test 4–Simple Penetration—Using the image obtained
stations, correctional institutions, corporate mailrooms, gov-
in 5.3.1.2, record the thicknesses of steel through which the
ernment offices, and other security areas.
lead numerals in the displayed image of the Test 4 test piece
5.3 Test Procedures:
can be seen on the monitor. Each lead numeral consists of a
5.3.1 Acquireanimageofthetestobjectinitscaseusingthe series of line segments.Alead numeral is considered visible if
more than half of the total length of the line segments can be
X-ray system.
seen and the numeral can be uniquely identified. Record aU
5.3.1.1 This test method specifies how to test a particular
in the log sheet box on each step for which both lead numerals
view in which the test object is placed at a particular position
are visible.
in the screening area. The test object shall be in its case and
5.3.6 Test 5–Thin Organic Imaging—Using the image ob-
orientedintheimagingsystemsuchthatthefaceofthethickest
tained in 5.3.1.2, record which circular holes are visible in the
attenuatoroftest7and8isperpendiculartotheX-raybeamfor
displayed image of the thin plastic of the Test 5 test piece. A
the X-ray view being tested. If the test object is misaligned by
hole is considered to be visible if it at least half of its area or
more than 3° then any test results are not valid (see A2.1 for
edge can be differentiated from the surrounding area. Record a
more details on ensuring proper alignment). It is acceptable to
U in the log sheet box on each hole that is visible.
tilt the test object (for example, by using a foam wedge) to
orient it properly. The normative position of the test object 5.3.7 Test 6–Steel Contrast Sensitivity—Using the image
obtained in 5.3.1.2, record which holes can be seen in the
shall be on the belt so that it is roughly centered between the
displayed image of the steel piece of the Test 6 test piece. A
edges of the belt and facing in the direction of the detector.
Testers of multiview systems should apply these test methods holeisconsideredtobevisibleifatleasthalfofitsareaoredge
canbedifferentiatedfromthesurroundingarea.RecordaUin
to all views offered by the system. The view being tested
should be recorded on the log sheet (Figs. 3 and 4). The tester the log sheet box on each hole that is visible.
mayalsoelecttomeasurethepositiondependenceoftheimage
5.3.8 Test 7–Materials Discrimination—Using the image
qualitymetricsthroughouttheinspectionvolume.Theposition
obtained in 5.3.1.2, study the displayed image of the test piece
and orientation of the test object should be recorded on the log
for Test 7 and record if there is a difference in hue between
sheet.
horizontally-neighboring squares. Neighboring squares are
considered differentiated if they are displayed with a percep-
5.3.1.2 All nine tests should be scored based on a single
tibly different hue. If the squares differ only in brightness, then
captured X-ray image and on the perception of one person.
they are not considered differentiated. Record aU in the log
ThiscapturedimagewillbepresentedtothetesterontheX-ray
sheet box between each of the differentiated squares.
system’s display. To achieve the best image for each test, it
maybenecessarytouseenhancementfeaturessuchaszoomas 5.3.9 Test 8–Materials Classification—Using the image ob-
well as brightness and contrast enhancements, etc. This is an tained in 5.3.1.2, study the displayed image of test piece for
acceptablepractice,butforeachtest,theenhancementfeatures Test 8 and record if the squares in each column show a
usedmustberecordedonthelogsheet(giveninFigs.3and4). consistent hue. A materials misclassification is considered to
The tester should record the temperature and humidity on the have occurred in a column if any two squares in that column
log sheet and ensure they are within the manufacturer recom- aredisplayedwithaperceptiblydifferenthue.MarkaUinthe
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F792 − 17
FIG. 3 Practice F792 – HP Log Sheet Page 1
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F792 − 17
FIG. 4 Practice F792 – HP Log Sheet Page 2
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F792 − 17
log sheet box for each of the columns in which all materials 6. Part OE
have been classified with a consistent hue.
6.1 Significance and Use:
5.3.10 Test 9–Organic Differentiation—Using the image
6.1.1 This practice applies to and establishes methods to
obtained in 5.3.1.2, study the displayed image of the test piece
measure the imaging performance of X-ray systems used for
used for Test 9. Observe if there is a difference in hue between
security screening. Such systems are typically used to screen
thefourorganicsamples.Samplesareconsidereddifferentiated
for prohibited items such as weapons, explosives, and explo-
if they are displayed with a perceptibly different hue. If the
sive devices in baggage, packages, cargo, or mail.
samples differ only in brightness, then they are not considered
6.1.2 The most significant attributes of this practice are the
differentiated.MarkaUinthelogsheetboxbetweeneachpair
design of test object and standard methods for determining the
of differentiated squares.
performance levels of the system.
5.4 Evaluation Considerations:
6.1.3 This practice applies to and establishes methods to
5.4.1 General—Use of this pract
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