ASTM E1862-97e1
(Test Method)Standard Test Methods for Measuring and Compensating for Reflected Temperature Using Infrared Imaging Radiometers
Standard Test Methods for Measuring and Compensating for Reflected Temperature Using Infrared Imaging Radiometers
SCOPE
1.1 These test methods cover procedures for measuring and compensating for reflected temperature when measuring the surface temperature of a specimen with an infrared imaging radiometer.
1.2 These test methods may involve use of equipment and materials in the presence of heated or electrically energized equipment, or both.
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
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Standards Content (Sample)
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Designation: E 1862 – 97 An American National Standard
Standard Test Methods for
Measuring and Compensating for Reflected Temperature
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Using Infrared Imaging Radiometers
This standard is issued under the fixed designation E 1862; 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.
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e NOTE—Editorial changes were made throughout in June 1998.
1. Scope temperature of a specimen, the Reflector Method and the
Direct Method.
1.1 These test methods cover procedures for measuring and
4.2 A test method is also given for compensating for the
compensating for reflected temperature when measuring the
error produced by reflected temperature using the computer
surface temperature of a specimen with an infrared imaging
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built into an infrared imaging radiometer.
radiometer.
1.2 These test methods may involve use of equipment and
5. Significance and Use
materials in the presence of heated or electrically energized
5.1 The infrared energy that is reflected by a specimen can
equipment, or both.
cause measurement errors for an infrared thermographer mea-
1.3 This standard does not purport to address all of the
suring its surface temperature. Two test methods are provided
safety concerns, if any, associated with its use. It is the
for measuring and compensating for this reflected temperature
responsibility of the user of this standard to establish appro-
error source, the Reflector Method and the Direct Method.
priate safety and health practices and determine the applica-
5.2 These test methods can be used in the field or laboratory
bility of regulatory limitations prior to use.
using commonly available materials.
2. Referenced Documents 5.3 These test methods can be used with any infrared
radiometers that have the required computer capabilities.
2.1 ASTM Standards:
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E 1316 Terminology for Nondestructive Examinations
6. Interferences
3. Terminology 6.1 Reflector Method:
6.1.1 This test method uses an infrared reflector with an
3.1 Definitions:
assumed reflectance of 1.00, which is an ideal property. Errors
3.1.1 diffuse reflector, n—a surface that produces a diffuse
can be minimized by using a reflector having a reflectance as
image of a reflected source.
close as possible to 1.00.
3.1.2 infrared thermographer, n—the person using an infra-
6.1.2 Specimens vary in that they can be diffuse or spectral
red imaging radiometer.
reflectors, or both. Use of an infrared reflector with reflectance
3.1.3 infrared reflector, n—a material with a reflectance as
properties as close as possible to those of the specimen will
close as possible to 1.00.
reduce errors.
3.1.4 reflected temperature, n—the temperature of the en-
6.2 Direct Method:
ergy incident upon and reflected from the measurement surface
6.2.1 The Direct Method usually does not account for the
of a specimen.
heat from the infrared thermographer’s body as a source of
3.1.5 specular reflector, n—a surface that produces a direct
reflected temperature. If this heat source creates a significant
image of a reflected source.
error, use the Reflector Method.
3.2 See also Terminology E 1316.
6.3 Reflected temperature errors produced by a point
4. Summary of Test Methods
source, such as the sun or a lamp, are difficult to measure
accurately. These error sources can often be avoided by moving
4.1 Two test methods are given for measuring the reflected
the infrared imaging radiometer’s position and angle relative to
the specimen.
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These test methods are under the jurisdiction of ASTM Committee E-7 on
6.4 The measured reflected temperature of a specimen may
Nondestructive Testing and are the direct responsibility of Subcommittee E07.10 on
Emerging NDT Methods. be specific to the waveband of the infrared imaging radiometer
Current edition approved April 10, 1997. Published June 1997.
used. Therefore, the infrared imaging radiometer’s waveband
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These test methods are adapted from the Guideline for Measuring and
should be noted with the measured value.
Compensating for Reflected Temperature, Emittance and Transmittance, 1993,
developed by the Infraspection Institute, 1971 Shelburne Rd., Shelburne, VT 05482. 6.5 The significance of the error contributed by reflected
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Annual Book of ASTM Standards, Vol 03.03.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
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E 1862
FIG. 1 Reflector Method
temperature can be estimated by shielding the specimen from 8.2.3 Point the infrared imaging radiometer at the specimen
various angles and observing any changes in the thermal and focus on the portion where the reflected temperature is to
image. be measured.
6.6 The error caused by reflected temperature can be re- 8.2.4 Estimate or measure the angle of reflection and the
duced by shielding the spe
...
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