ASTM E1311-14
(Practice)Standard Practice for Minimum Detectable Temperature Difference for Thermal Imaging Systems
Standard Practice for Minimum Detectable Temperature Difference for Thermal Imaging Systems
SIGNIFICANCE AND USE
5.1 This practice gives a measure of a thermal imaging system's effectiveness for detecting a small spot within a large background. Thus, it relates to the detection of small material defects such as voids, pits, cracks, inclusions, and occlusions.
5.2 MDTD values provide estimates of detection capability that may be used to compare one system with another. (Lower MDTD values indicate better detection capability.)
5.3 Due to the partially subjective nature of the procedure, repeatability and reproducibility are apt to be poor and MDTD differences less than 0.2°C are considered to be insignificant.
Note 2: Values obtained under idealized laboratory conditions may or may not correlate directly with service performance.
SCOPE
1.1 This practice covers the determination of the minimum detectable temperature difference (MDTD) capability of a compound observer-thermal imaging system as a function of the angle subtended by the target.
1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.3 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: E1311 − 14
Standard Practice for
Minimum Detectable Temperature Difference for Thermal
1
Imaging Systems
This standard is issued under the fixed designation E1311; 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* 4. Summary of Practice
4.1 A standard circular target is used in conjunction with a
1.1 This practice covers the determination of the minimum
detectable temperature difference (MDTD) capability of a differentialblackbodythatcanestablishoneblackbodyisother-
mal temperature for the target and another blackbody isother-
compound observer-thermal imaging system as a function of
the angle subtended by the target. mal temperature for the background by which the target is
framed. The target, at an undisclosed orientation, is imaged
1.2 The values stated in SI units are to be regarded as
onto the monochrome video monitor of a thermal imaging
standard. No other units of measurement are included in this
system whence the image may be viewed by an observer. The
standard.
temperature difference between the target and the background,
1.3 This standard does not purport to address all of the
initially zero, is increased incrementally until the observer, in a
safety problems, if any, associated with its use. It is the
limited duration, can just distinguish the target. This critical
responsibility of the user of this standard to establish appro-
temperature difference is the MDTD.
priate safety and health practices and determine the applica-
NOTE 1—Observers must have good eyesight and be familiar with
bility of regulatory limitations prior to use.
viewing thermal imagery.
4.2 The temperature distributions of each target and its
2. Referenced Documents
background are measured remotely at the critical temperature
2
2.1 ASTM Standards:
difference that defines the MDTD.
E1316 Terminology for Nondestructive Examinations
4.3 The background temperature and the angular subtense
for each target are specified together with the measured value
3. Terminology
of MDTD. The (fixed) field of view included by the back-
3.1 Definitions:
ground is also specified.
3.1.1 differential blackbody—an apparatus for establishing
4.4 The probability of detection is specified together with
two parallel isothermal planar zones of different temperatures,
the reported value of MDTD.
and with effective emissivities of 1.0.
3.1.2 field of view (FOV)—the shape and angular dimen-
5. Significance and Use
sions of the cone or the pyramid that define the object space
5.1 This practice gives a measure of a thermal imaging
imaged by the system; for example, rectangular, 4-deg wide by
system’s effectiveness for detecting a small spot within a large
3-deg high.
background. Thus, it relates to the detection of small material
3.1.2.1 Discussion—The size of the field of view is custom-
defects such as voids, pits, cracks, inclusions, and occlusions.
arily expressed in units of degrees.
5.2 MDTD values provide estimates of detection capability
3.1.3 See also Terminology E1316.
that may be used to compare one system with another. (Lower
MDTD values indicate better detection capability.)
5.3 Due to the partially subjective nature of the procedure,
1
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
repeatability and reproducibility are apt to be poor and MDTD
structive Testing and is the direct responsibility of Subcommittee E07.10 on
Specialized NDT Methods.
differences less than 0.2°C are considered to be insignificant.
Current edition approved Oct. 1, 2014. Published October 2014. Originally
NOTE 2—Values obtained under idealized laboratory conditions may or
approved in 1989. Last previous edition approved in 2010 as E1311 - 89 (2010).
DOI: 10.1520/E1311-14. may not correlate directly with service performance.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
6. Apparatus
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. 6.1 The apparatus consists of the following:
*A Summary of Changes section appears at the end of this standard
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
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E1311 − 14
6.1.1 Target Plates, containing single or multiple circular 7.5 Make the display luminance and the laboratory ambient
targets of area(s) not greater than 5 % of the combined areas of luminance mutually suitable for visual acuity and viewing
target and background (tha
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: E1311 − 89 (Reapproved 2010) E1311 − 14
Standard Test Method Practice for
Minimum Detectable Temperature Difference for Thermal
1
Imaging Systems
This standard is issued under the fixed designation E1311; 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
1.1 This test method covers the determination of the minimum detectable temperature difference (MDTD) capability of a
compound observer-thermal imaging system as a function of the angle subtended by the target.
1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
E1316 Terminology for Nondestructive Examinations
3. Terminology
3.1 Definitions:
3.1.1 differential blackbody—an apparatus for establishing two parallel isothermal planar zones of different temperatures, and
with effective emissivities of 1.0.
3.1.2 field of view (FOV)—the shape and angular dimensions of the cone or the pyramid that define the object space imaged
by the system; for example, rectangular, 4-deg wide by 3-deg high.
1
This test method practice is under the jurisdiction of ASTM Committee E07 on Nondestructive Testing and is the direct responsibility of Subcommittee E07.10 on
Specialized NDT Methods.
Current edition approved June 1, 2010Oct. 1, 2014. Published November 2010October 2014. Originally approved in 1989. Last previous edition approved in 20042010
as E1311 - 89 (2004).(2010). DOI: 10.1520/E1311-89R10.10.1520/E1311-14.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
3.1.2.1 Discussion—
The size of the field of view is customarily expressed in units of degrees.
3.1.3 See also Terminology E1316.
4. Summary of Test Method
4.1 A standard circular target is used in conjunction with a differential blackbody that can establish one blackbody isothermal
temperature for the target and another blackbody isothermal temperature for the background by which the target is framed. The
target, at an undisclosed orientation, is imaged onto the monochrome video monitor of a thermal imaging system whence the image
may be viewed by an observer. The temperature difference between the target and the background, initially zero, is increased
incrementally until the observer, in a limited duration, can just distinguish the target. This critical temperature difference is the
MDTD.
NOTE 1—Observers must have good eyesight and be familiar with viewing thermal imagery.
4.2 The temperature distributions of each target and its background are measured remotely at the critical temperature difference
that defines the MDTD.
4.3 The background temperature and the angular subtense for each target are specified together with the measured value of
MDTD. The (fixed) field of view included by the background is also specified.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
---------------------- Page: 1 ----------------------
E1311 − 14
4.4 The probability of detection is specified together with the reported value of MDTD.
5. Significance and Use
5.1 This test method gives a measure of a thermal imaging system’s effectiveness for detecting a small spot within a large
background. Thus, it relates to the detection of small material defects such as voids, pits, cracks, inclusions, and occlusions.
5.2 MDTD values provide estimates of detection capability that may be used to compare one system with another. (Lower
MDTD values indicate better detection capability.)
NOTE 2—Test values obtained under idealized laboratory conditions may or may not correlate directly with service performance.
6. Apparatus
6.1 The apparatus consists of the following:
6.1.1 Target Plates, containing single or multiple circular targets of area(s) not greater than 5 % of the combined areas of target
and background (that is, FOV area), and with the distance from the center of the target to the center of the FOV equal to
...
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