ASTM E1213-14

Standard Practice for Minimum Resolvable Temperature Difference for Thermal Imaging Systems

SIGNIFICANCE AND USE
5.1 This practice relates to a thermal imaging system's effectiveness for discerning details in a scene.  
5.2 MRTD values provide estimates of resolution capability and may be used to compare one system with another. (Lower MRTD values indicate better resolution.)  
5.3 Due to the partially subjective nature of the procedure, repeatability and reproducibility are apt to be poor and MRTD differences less than 0.2°C are considered to be insignificant.
Note 1: 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 resolvable temperature difference (MRTD) capability of the compound observer-thermal imaging system as a function of spatial frequency.  
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 concerns, 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.

General Information

• Status: Historical
• Publication Date: 30-Sep-2014
• ICS: 17.180.20 - Colours and measurement of light
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.10 - Specialized NDT Methods

Relations

• Replaces: ASTM E1213-97(2009) - Standard Test Method for Minimum Resolvable Temperature Difference for Thermal Imaging Systems
• Effective Date: 01-Oct-2014
• Referred By: ASTM E3045-22 - Standard Practice for Crack Detection Using Vibroacoustic Thermography
• Effective Date: 01-Oct-2014
• Referred By: ASTM C1060-23 - Standard Practice for Thermographic Inspection of Insulation Installations in Envelope Cavities of Frame Buildings
• Effective Date: 01-Oct-2014
• Referred By: ASTM E1543-14(2022) - Standard Practice for Noise Equivalent Temperature Difference of Thermal Imaging Systems
• Effective Date: 01-Oct-2014
• Referred By: ASTM E3353-22 - Standard Guide for In-Process Monitoring Using Optical and Thermal Methods for Laser Powder Bed Fusion
• Effective Date: 01-Oct-2014
• Referred By: ASTM E2533-21 - Standard Guide for Nondestructive Examination of Polymer Matrix Composites Used in Aerospace Applications
• Effective Date: 01-Oct-2014
• Referred By: ASTM C1153-10(2015) - Standard Practice for Location of Wet Insulation in Roofing Systems Using Infrared Imaging
• Effective Date: 01-Oct-2014

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: E1213 − 14
Standard Practice for
Minimum Resolvable Temperature Difference for Thermal
1
Imaging Systems
This standard is issued under the fixed designation E1213; 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* imaging system where the image is viewed by an observer.The
temperature difference between the bars and their conjugates,
1.1 This practice covers the determination of the minimum
initially zero, is increased incrementally only until the observer
resolvable temperature difference (MRTD) capability of the
can distinguish the four bars. This critical temperature differ-
compound observer-thermal imaging system as a function of
ence is the MRTD.
spatial frequency.
4.2 The spatial distribution of temperature of each target
1.2 The values stated in SI units are to be regarded as
must be measured remotely at the critical temperature differ-
standard. No other units of measurement are included in this
encethatdeterminestheMRTD.Themeantemperatureofeach
standard.
bar must not differ from that of any other bar by more than the
1.3 This standard does not purport to address all of the
measured MRTD. A similar requirement applies to the tem-
safety concerns, if any, associated with its use. It is the
perature of each conjugate bar. Otherwise the MRTD value is
responsibility of the user of this standard to establish appro-
unacceptable.
priate safety and health practices and determine the applica-
4.3 The background temperature and the spatial frequency
bility of regulatory limitations prior to use.
of each target must be specified together with the measured
2. Referenced Documents
value of MRTD.
2
2.1 ASTM Standards: 4.4 The probability of resolution must be specified together
E1316 Terminology for Nondestructive Examinations
with the reported value of MRTD.
3. Terminology
5. Significance and Use
3.1 Definitions:
5.1 This practice relates to a thermal imaging system’s
3.1.1 differential blackbody—an apparatus for establishing
effectiveness for discerning details in a scene.
two parallel isothermal planar zones of different temperatures,
5.2 MRTD values provide estimates of resolution capability
and with effective emissivities of 1.0.
and may be used to compare one system with another. (Lower
3.1.2 See also Terminology E1316.
MRTD values indicate better resolution.)
5.3 Due to the partially subjective nature of the procedure,
4. Summary of Practice
repeatability and reproducibility are apt to be poor and MRTD
4.1 A standard four-bar target is used in conjunction with a
differences less than 0.2°C are considered to be insignificant.
differential blackbody that can establish one blackbody isother-
mal temperature for the set of bars and another blackbody NOTE 1—Values obtained under idealized laboratory conditions may or
may not correlate directly with service performance.
isothermal temperature for the set of conjugate bars, which are
formed by the regions between the bars (see Fig. 1). The target
6. Apparatus
is imaged onto the monochrome video monitor of a thermal
6.1 The apparatus consists of the following:
6.1.1 Comparison Charts (Targets), comprised of four pe-
1
This practice is under the jurisdiction of ASTM Committee E07 on Nonde-
riodic bars of aspect ratio (width:height) 1:7, as shown in Fig.
structive Testing and is the direct responsibility of Subcommittee E07.10 on
Specialized NDT Methods.
1.
Current edition approved Oct. 1, 2014. Published October 2014. Originally
6.1.2 Differential Blackbody, temporally stable and control-
approved in 1987. Last previous edition approved in 2009 as E1213 - 97(2009).
lable to within 0.1°C.
DOI: 10.1520/E1213-14.
2
6.1.3 Infrared Spot Radiometer, calibrated with the aid of a
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
blackbody source to an accuracy within 0.1°C.
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. NOTE 2—Comparison charts may be fabricated by cutting slots in metal
*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
1

---------------------- Page: 1 ----------------------
E1213 − 14
FIG. 1 Targets Used for MRTD Determinations
and coating with black paint of emissivity greater than 0.95. In this case
7.10 Calculate the mean temperature of each bar and inter-
the slots would constitute the bars.
compare the values, and calculate the mean temperature o
...

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: E1213 − 97 (Reapproved 2009) E1213 − 14
Standard Test Method Practice for
Minimum Resolvable Temperature Difference for Thermal
1
Imaging Systems
This standard is issued under the fixed designation E1213; 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 resolvable temperature difference (MRTD) capability of the
compound observer-thermal imaging system as a function of spatial frequency.
1.2 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 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 See also Terminology E1316.
4. Summary of Test Method
4.1 A standard four-bar target is used in conjunction with a differential blackbody that can establish one blackbody isothermal
temperature for the set of bars and another blackbody isothermal temperature for the set of conjugate bars, which are formed by
the regions between the bars (see Fig. 1). The target is imaged onto the monochrome video monitor of a thermal imaging system
where the image is viewed by an observer. The temperature difference between the bars and their conjugates, initially zero, is
increased incrementally only until the observer can distinguish the four bars. This critical temperature difference is the MRTD.
4.2 The spatial distribution of temperature of each target must be measured remotely at the critical temperature difference that
determines the MRTD. The mean temperature of each bar must not differ from that of any other bar by more than the measured
MRTD. A similar requirement applies to the temperature of each conjugate bar. Otherwise the MRTD value is unacceptable.
4.3 The background temperature and the spatial frequency of each target must be specified together with the measured value
of MRTD.
4.4 The probability of resolution must be specified together with the reported value of MRTD.
5. Significance and Use
5.1 This test relates to a thermal imaging system’s effectiveness for discerning details in a scene.
5.2 MRTD values provide estimates of resolution capability and may be used to compare one system with another. (Lower
MRTD values indicate better resolution.)
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
EmergingSpecialized NDT Methods.
Current edition approved March 1, 2009Oct. 1, 2014. Published March 2009October 2014. Originally approved in 1987. Last previous edition approved in 20022009 as
E1213 - 97(2002).(2009). DOI: 10.1520/E1213-97R09.10.1520/E1213-14.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1

---------------------- Page: 1 ----------------------
E1213 − 14
FIG. 1 Targets Used for MRTD Determinations
NOTE 1—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 Test Charts (Targets), comprised of four periodic bars of aspect ratio (width:height) 1:7, as shown in Fig. 1.
6.1.2 Differential Blackbody, temporally stable and controllable to within 0.1°C.
6.1.3 Infrared Spot Radiometer, calibrated with the aid of a blackbody source to an accuracy within 0.1°C.
NOTE 2—Test charts may be fabricated by cutting slots in metal and coating with black paint of emissivity greater than 0.95. In this case the slots would
constitute the bars.
7. Procedure
7.1 Mount a test chart (target) onto the differential blackbody.
NOTE 3—Differential blackbodies may
...