ASTM F1181-96
(Test Method)Standard Test Method for Measuring Binocular Disparity in Transparent Parts
Standard Test Method for Measuring Binocular Disparity in Transparent Parts
SCOPE
1.1 This test method determines the amount of binocular disparity that is induced by transparent parts such as aircraft windscreens, canopies, HUD combining glasses, visors or goggles. This test method may be applied to parts of any size, shape or thickness, individually or in combination, so as to determine the contribution of each transparent part to the overall binocular disparity present in the total "viewing system" being used by a human operator.
1.2 This test method represents one of several techniques that are available for measuring binocular disparity, but is the only technique that yields a quantitative figure of merit that can be related to operator visual performance.
1.3 This test method employs apparatus currently being used in the measurement of optical angular deviation under Method F801.
1.4 This standard may involve hazardous materials, operations, and equipment. This standard does not purport to address all of the safety problems 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.
1.5 The values stated in inch-pound units are the preferred units. The values in parentheses are for information only.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: F 1181 – 96
Standard Test Method for
Measuring Binocular Disparity in Transparent Parts
This standard is issued under the fixed designation F 1181; 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 between the two eyes when viewing an object at a fixation
point or due to the fact that an object is either nearer or farther
1.1 This test method determines the amount of binocular
than the fixation point. A certain amount of disparity is
disparity that is induced by transparent parts such as aircraft
beneficial and natural, leading to the perception of depth.
windscreens, canopies, HUD combining glasses, visors or
However, when the disparity exceeds the limits for binocular
goggles. This test method may be applied to parts of any size,
fusion, doubling of vision, eye fatigue, and headaches occur as
shape or thickness, individually or in combination, so as to
the eyes strain to merge the disparate images.
determine the contribution of each transparent part to the
3.1.3 diplopia—the doubling of images of an object due to
overall binocular disparity present in the total “viewing sys-
the fact that the object is either nearer or farther than the point
tem” being used by a human operator.
of fixation or due to the fact that the lines of regard of the eyes
1.2 This test method represents one of several techniques
do not intersect at the point of fixation.
that are available for measuring binocular disparity, but is the
3.1.4 Panum’s area—the area on the retina in which the
only technique that yields a quantitative figure of merit that can
eyes are able to fuse disparate images so that single vision
be related to operator visual performance.
occurs.
1.3 This test method employs apparatus currently being
used in the measurement of optical angular deviation under
4. Summary of Test Method
Method F 801.
4.1 Using an optoelectronic system (consisting of a trans-
1.4 This standard does not purport to address all of the
mitter and a receiver) and with the part held in its installed
safety concerns, if any, associated with its use. It is the
angle, two sets of angular deviation measurements are made at
responsibility of the user of this standard to establish appro-
several intervals (for example, 2°) in both azimuth and eleva-
priate safety and health practices and determine the applica-
tion. The extent of the area to be measured is dependent on the
bility of regulatory limitations prior to use.
type of part being measured, for example, windscreen, visor,
1.5 The values stated in inch-pound units are the preferred
etc. The first set of measures is taken from the left eye position,
units. The values in parentheses are for information only.
the second from the right eye position. The separation between
2. Referenced Documents the two eye positions is 2.5 in. (6.35 cm), a distance equivalent
to the interpupillary distance between the human eyes. The
2.1 ASTM Standards:
measurements taken from the left eye position are subtracted
F 801 Test Method for Measuring Optical Angular Devia-
2 from that taken from the right eye position to determine
tion of Transparent Parts
binocular disparity.
3. Terminology
5. Significance of Use
3.1 Definitions:
5.1 Diplopia or doubling of vision occurs when there is
3.1.1 angular deviation—the angular displacement of a
sufficient binocular disparity present so that the bounds of
light ray as it passes through a transparent part, expressed as an
Panum’s area (the area of single vision) is exceeded. This
angular measurement, for example, degree, minutes of arc,
condition arises whenever one object is significantly closer (or
milliradians. Since it is an angular measurement, the amount of
farther) than another so that looking at one will cause the image
displacement increases with distance.
of the other to appear double. This can be easily demonstrated:
3.1.2 binocular disparity—the difference between the two
Close one eye and look at a clock (or other object) on a distant
images on the retina resulting from the lateral separation
wall. Now place your thumb to one side of the image of the
clock. Now open both eyes. If you look at the clock, you
should see two thumbs. If you look at your thumb, you should
This test method is under the jurisdiction of ASTM Committee F-7 on
see two clocks.
Aerospace and Aircraft and is the direct responsibility of Subcommittee F07.08 on
Transparent Enclosures and Materials. 5.2 Complaints from pilots flying aircraft equipped with
Current edition approved Nov. 10, 1996. Published January 1997. Originally
wide field of view HUDs such as the LANTIRN HUD
published as F 1181 – 88. Last previous edition F 1181 – 88.
indicated that they were experiencing discomfort (eye fatigue,
Annual Book of ASTM Standards, Vol 15.03.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
NOTICE: This standard has either been superceded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
F 1181
headaches, etc.) or seeing either two targets or two pippers 8.4 Establish a baseline or zero determination without a
when using the HUD. Subsequent investigations revealed that transparency in the optical path. Record the number as dis-
the problem arose from the fact that the transparency and the played on the digital readout under this condition.
HUD significantly changed the optical distances of the target 8.5 Locate the transparency part between the transmitter and
and the HUD imagery so that binocular disparity which
receiver. Take the readings from left (right) eye position over
exceeded Panum’s area was induced. Use of this test method area of interest as specified by using activity. Record readings
provides a procedure by which the amount of binocular
for each point (azimuth, elevation) of the transparency that is
disparity being experienced by a human operator due to the measured. Determine differences between these readings and
presence of a transparent part in his field of view may be easily readings (8.4) made without the transparency in place.
and precisely measured. 8.6 Repeat 8.5, taking readings with the transmitter located
and firmly mounted at right (left) eye position or as appropri-
6. Apparatus
ate.
6.1 Transmitter capable of projecting collimated light rays
from a suitable target. The transmitter should be firmly fixed to
9. Calculation and Report
the floor or other stationary fixture.
9.1 Determine the amount of horizontal and vertical binocu-
6.2 Receiver firmly affixed to the floor or a stable platform
lar disparity present in the transparent part by completing the
consisting of the following components:
calculations set forth in paragraphs 9.1.1-9.1.4. Azimuth scores
6.2.1 Displacement Compensation and Imaging Lens with
will yield horizontal disparity, elevation scores will yield
a foca
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.