ASTM E1543-00

Standard Test Method for Noise Equivalent Temperature Difference of Thermal Imaging Systems

SCOPE
1.1 This test method covers the determination of the noise equivalent temperature difference (NETD; NE[delta]T) of thermal imaging systems of the conventional forward-looking infrared (FLIR) or other types that utilize an optical-mechanical scanner; it does not include charge-coupled devices or pyroelectric vidicons.
1.2 Parts of this test method have been formulated under the assumption of a photonic detector(s) at a standard background temperature of 295°K (22°C). Besides non-uniformity, tests made at other background temperatures may result in impairment of precision and bias.
1.3 The values stated in SI units are to be regarded as the standard.
1.4 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: 09-Feb-2000
• ICS: 17.200.20 - Temperature-measuring instruments
• Technical Committee: E07 - Nondestructive Testing
• Drafting Committee: E07.10 - Specialized NDT Methods

Relations

• Replaced By: ASTM E1543-00(2006) - Standard Test Method for Noise Equivalent Temperature Difference of Thermal Imaging Systems
• Effective Date: 01-May-2006
• Referred By: ASTM E3353-22 - Standard Guide for In-Process Monitoring Using Optical and Thermal Methods for Laser Powder Bed Fusion
• Effective Date: 10-Feb-2000
• Referred By: ASTM E2533-21 - Standard Guide for Nondestructive Examination of Polymer Matrix Composites Used in Aerospace Applications
• Effective Date: 10-Feb-2000

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NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.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: E 1543 – 00
Standard Test Method for
Noise Equivalent Temperature Difference of Thermal
Imaging Systems
This standard is issued under the fixed designation E 1543; 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 (e) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2 dwell time—the time spent, during one frame, in
scanning one angular dimension of a single pixel (picture
1.1 This test method covers the determination of the noise
element) of the image within the instantaneous field of view
equivalent temperature difference (NETD; NEDT) of thermal
(IFOV) of a detector. Thus, for example, if a single pixel is
imaging systems of the conventional forward-looking infrared
scanned n times during one frame, the dwell time is given by
(FLIR) or other types that utilize an optical-mechanical scan-
n times the duration of a single scan of the pixel.
ner; it does not include charge-coupled devices or pyroelectric
3.1.3 FLIR—an acronym for forward-looking infrared,
vidicons.
originally implying airborne, now denoting any fast-frame
1.2 Parts of this test method have been formulated under the
thermal imaging system comparable to that of television and
assumption of a photonic detector(s) at a standard background
yielding real-time displays. Generally, these systems employ
temperature of 295°K (22°C). Besides nonuniformity, tests
optical-mechanical scanning mechanisms.
made at other background temperatures may result in impair-
3.1.4 See also Section J: Infrared Examination, of Termi-
ment of precision and bias.
nology E 1316.
1.3 The values stated in SI units are to be regarded as the
standard.
4. Summary of Test Method
1.4 This standard does not purport to address all of the
4.1 The target is a blackbody source of uniform temperature
safety concerns, if any, associated with its use. It is the
that is viewed by the infrared thermal imaging system through
responsibility of the user of this standard to establish appro-
an aperture of prescribed size. A specified temperature differ-
priate safety and health practices and determine the applica-
ence is established between the target and its background.
bility of regulatory limitations prior to use.
Measurements are made of the peak-to-peak signal voltage
2. Referenced Documents from the target and the RMS noise voltage from the back-
ground, both across a standard reference filter, and of the target
2.1 ASTM Standards:
andbackgroundtemperatures.Fromthesemeasuredvalues,the
E 1213 Test Method for Minimum Resolvable Temperature
2 NETD is calculated.
Difference for Thermal Imaging Systems
E 1316 Terminology for Nondestructive Examinations
5. Significance and Use
3. Terminology 5.1 This test method gives an objective measure of the
temperaturesensitivityofathermalimagingsystem(relativeto
3.1 Definitions:
a standard reference filter) exclusive of a monitor, with
3.1.1 blackbodysimulator—a device that produces an emis-
emphasis on the detector(s) and preamplifier.
sion spectrum closely approximating that emitted by a black-
body (surface with emissivity of 1.0), usually a cavity or a flat
NOTE 1—Test values obtained under idealized laboratory conditions
plate with a structured or coated surface having a stable and may or may not correlate directly with service performance.
uniform temperature.
5.2 This test method affords a convenient means for peri-
odically monitoring the performance of a given thermal imag-
ing system.
5.3 NETD relates to minimum resolvable temperature dif-
This test method is under the jurisdiction of ASTM Committee E-7 on
Nondestructive Testing and is the direct responsibility of Subcommittee E07.10 on
ference as described in Test Method E 1213. Thus, an increase
Emerging NDT Methods.
in NETD may be manifest as a loss of detail in imagery.
Current edition approved Feb. 10, 2000. Published April 2000. Originally
5.4 Intercomparisons based solely on NETD figures may be
published as E 1543 – 93. Last previous edition E 1543 – 94.
Annual Book of ASTM Standards, Vol 03.03. misleading.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
E1543–00
NOTE 2—NETD depends on various factors such as spectral bandwidth
and background temperature.
6. Apparatus
6.1 The apparatus, as shown in Fig. 1, consists of the
following:
6.1.1 Blackbody Simulator, temporally stable and control-
lable to within 0.1°C.
6.1.2 Target Plate, containing an aperture several times
larger dimensionally than the IFOV. The target plate should be
FIG. 2 Circuit Diagram of Standard Reference Filter
at least ten times the dimension of the aperture in both the
height and width. (The plate forms the target background; the
aperture, in effect, becomes the target as the blackbody
NOTE 5—If convenient, the filter may be a self-contained unit for
simulator is viewed through it.) The material and surface
external connection.
conditions of the target plate must be carefully considered. It is
6.1.5 Infrared Spot Radiometer or equivalent radiometric
helpful for the back side of the target plate to be a highly
instrument, calibrated with the aid of a blackbody source to an
reflective metallic surface to minimize the influence of the
accuracy within 0.1°C.
blackbody simulator on the temperature of the target back-
6.1.6 Digital Oscilloscope.
ground. The front surface of the target plate should appear to
6.1.7 Digital True RMS Voltmeter, with high crest factor
the infrared imaging system to have a high emissivity. One
(peak voltage/RMS voltage) so as not to attenuate any noise
possibility would be to coat the viewed surface with a high
peaks, and bandwidth from approximately zero to at least
emissivity paint or coating.
1.6/RC. See 6.1.4 and X1.1.
6.1.3 Target Cover, used to block completely the radiation
emanating from the target. The target cover should have front
7. Procedure
and back surface properties similar to those of the target plate.
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