ASTM F1165-20
(Test Method)Standard Test Method for Measuring Angular Displacement of Multiple Images in Transparent Parts
Standard Test Method for Measuring Angular Displacement of Multiple Images in Transparent Parts
SIGNIFICANCE AND USE
5.1 With the advent of thick, highly angled aircraft transparencies, multiple imaging has been more frequently cited as an optical problem by pilots. Secondary images (of outside lights), often varying in intensity and displacement across the windscreen, can give the pilot deceptive optical cues of his altitude, velocity, and approach angle, increasing his visual workload. Current specifications for multiple imaging in transparencies are vague and not quantitative. Typical specifications state “multiple imaging shall not be objectionable.”
5.2 The angular separation of the secondary and primary images has been shown to relate to the pilot's acceptability of the windscreen. This procedure provides a way to quantify angular separation so a more objective evaluation of the transparency can be made. This procedure is of use for research of multiple imaging, quantifying aircrew complaints, or as the basis for windscreen specifications.
5.3 It is of note that the basic multiple imaging characteristics of a windscreen are determined early in the design phase and are virtually impossible to change after the windscreen has been manufactured. In fact, a perfectly manufactured windscreen has some multiple imaging. For a particular windscreen, caution is advised in the selection of specification criteria for multiple imaging, as inherent multiple imaging characteristics have the potential to vary significantly depending upon windscreen thickness, material, or installation angle. Any tolerances that might be established are advised to allow for inherent multiple imaging characteristics.
SCOPE
1.1 This test method covers measuring the angular separation of secondary images from their respective primary images as viewed from the design eye position of an aircraft transparency. Angular separation is measured at 49 points within a 20 by 20° field of view. This procedure is designed for performance on any aircraft transparency in a laboratory or in the field. However, the procedure is limited to a dark environment. Laboratory measurements are done in a darkened room and field measurements are done at night (preferably between astronomical dusk and astronomical dawn).
1.2 Units—The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units are provided for information only and are not considered standard.
1.3 This standard possibly involves hazardous materials, operations, and equipment. This standard does not purport to address all of the safety concerns 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.
1.4 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.
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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.
Designation: F1165 − 20
Standard Test Method for
Measuring Angular Displacement of Multiple Images in
1
Transparent Parts
This standard is issued under the fixed designation F1165; 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 E691 Practice for Conducting an Interlaboratory Study to
Determine the Precision of a Test Method
1.1 This test method covers measuring the angular separa-
tion of secondary images from their respective primary images
3. Terminology (see Fig. 1)
as viewed from the design eye position of an aircraft transpar-
ency. Angular separation is measured at 49 points within a 20
3.1 angular displacement, n—the apparent angular separa-
by 20° field of view. This procedure is designed for perfor-
tion of the secondary image from the primary image as
mance on any aircraft transparency in a laboratory or in the
measured from the design eye position (θ).
field. However, the procedure is limited to a dark environment.
3.2 installed angle, n—the part attitude as installed in the
Laboratory measurements are done in a darkened room and
aircraft; the angle between the surface of the windscreen along
field measurements are done at night (preferably between
its crest and the pilot’s 0° azimuth, 0° elevation line of sight.
astronomical dusk and astronomical dawn).
3.3 primary image, n—the image formed by the rays trans-
1.2 Units—The values stated in SI units are to be regarded
mitted through the transparency without being reflected (solid
as standard. The values given in parentheses after SI units are
lines).
provided for information only and are not considered standard.
3.4 secondary image, n—the image resulting from internal
1.3 This standard possibly involves hazardous materials,
reflections of light rays at the surfaces of the transparency
operations, and equipment. This standard does not purport to
(dashed lines).
address all of the safety concerns associated with its use. It is
the responsibility of the user of this standard to establish
4. Summary of Test Method
appropriate safety, health, and environmental practices and
determine the applicability of regulatory limitations prior to
4.1 The procedure for determining the angular displacement
use.
of secondary images entails photographing a light array of
1.4 This international standard was developed in accor-
known size and distance from the transparency. The photo-
dance with internationally recognized principles on standard-
graph is then used to make linear measurements of the image
ization established in the Decision on Principles for the
separation, which can be converted to angular separation using
Development of International Standards, Guides and Recom-
a scale factor based on the known geometry.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
5. Significance and Use
5.1 With the advent of thick, highly angled aircraft
2. Referenced Documents
transparencies, multiple imaging has been more frequently
2
2.1 ASTM Standards:
cited as an optical problem by pilots. Secondary images (of
E177 Practice for Use of the Terms Precision and Bias in
outside lights), often varying in intensity and displacement
ASTM Test Methods
across the windscreen, can give the pilot deceptive optical cues
of his altitude, velocity, and approach angle, increasing his
visual workload. Current specifications for multiple imaging in
1
This test method is under the jurisdiction of ASTM Committee F07 on
transparencies are vague and not quantitative. Typical specifi-
Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.08 on
Transparent Enclosures and Materials.
cations state “multiple imaging shall not be objectionable.”
Current edition approved May 1, 2020. Published May 2020. Originally
5.2 The angular separation of the secondary and primary
approved in 1988. Last previous edition approved in 2015 as F1165 – 15. DOI:
10.1520/F1165-20.
images has been shown to relate to the pilot’s acceptability of
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
the windscreen. This procedure provides a way to quantify
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
angular separation so a more objective evaluation of the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. transparencycanbemade.Thisprocedureisofuseforresearch
Copyright © ASTM International, 100
...
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: F1165 − 15 F1165 − 20
Standard Test Method for
Measuring Angular Displacement of Multiple Images in
1
Transparent Parts
This standard is issued under the fixed designation F1165; 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 measuring the angular separation of secondary images from their respective primary images as
viewed from the design eye position of an aircraft transparency. Angular separation is measured at 49 points within a 20 by 20°
field of view. This procedure is designed for performance on any aircraft transparency in a laboratory or in the field. However, the
procedure is limited to a dark environment. Laboratory measurements are done in a darkened room and field measurements are
done at night.night (preferably between astronomical dusk and astronomical dawn).
1.2 Units—The values stated in SI units are to be regarded as standard. No other units of measurement are included in this The
values given in parentheses after SI units are provided for information only and are not considered standard.
1.2.1 Exception—The values in parentheses are for information only.
1.3 This standard possibly involves hazardous materials, operations, and equipment. This standard does not purport to address
all of the safety concerns,concerns associated with its use. It is the responsibility of the user of this standard to establish
appropriate safety safety, health, and healthenvironmental practices and determine the applicability of regulatory limitations prior
to use.
1.4 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.
2. Referenced Documents
2
2.1 ASTM Standards:
E177 Practice for Use of the Terms Precision and Bias in ASTM Test Methods
E691 Practice for Conducting an Interlaboratory Study to Determine the Precision of a Test Method
3. Terminology (see Fig. 1)
3.1 primary image—the image formed by the rays transmitted through the transparency without being reflected (solid lines).
3.2 secondary image—the image resulting from internal reflections of light rays at the surfaces of the transparency (dashed
lines).
3.1 angular displacement—displacement, n—the apparent angular separation of the secondary image from the primary image
as measured from the design eye position (θ).
3.2 installed angle—angle, n—the part attitude as installed in the aircraft; the angle between the surface of the windscreen along
its crest and the pilot’s 0° azimuth, 0° elevation line of sight.
3.3 primary image, n—the image formed by the rays transmitted through the transparency without being reflected (solid lines).
3.4 secondary image, n—the image resulting from internal reflections of light rays at the surfaces of the transparency (dashed
lines).
1
This test method is under the jurisdiction of ASTM Committee F07 on Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.08 on Transparent
Enclosures and Materials.
Current edition approved Nov. 1, 2015May 1, 2020. Published November 2015May 2020. Originally approved in 1988. Last previous edition approved in 20102015 as
F1165 – 10.F1165 – 15. DOI: 10.1520/F1165-15.10.1520/F1165-20.
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.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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F1165 − 20
FIG. 1 Drawing of Light Ray Paths that Cause an Apparent Angular Separation (θ) Between the Primary Image and the Secondary Im-
age
4. Summary of Test Method
4.1 The procedure for determining the angular displacement of secondary images entails photographing a light array of known
size and distance from the transparency. The photograph is then used to make linear measurements of the image separation, which
can be converted to angular separation using a scale factor based on the
...
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