IEC TR 62629-1-3:2026

IEC TR 62629-1-3 ®
Edition 1.0 2026-02
TECHNICAL
REPORT
3D displays -
Part 1-3: Generic - Human depth perception and the determination of the
position of 3D object on the non-physical screen
ICS 31.120; 31.260 ISBN 978-2-8327-0991-7

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CONTENTS
FOREWORD . 2
1 Scope . 4
2 Normative references . 4
3 Terms, definitions and abbreviated terms . 4
3.1 Terms and definitions . 4
3.2 Abbreviated terms. 4
4 Perception of the depth by human . 5
4.1 Horopter . 5
4.2 Panum's fusional area . 6
4.3 Stereo acuity . 6
4.4 Panum's fusional area and stereo acuity represented in length . 7
5 Focal power and accommodation of the human eye. 8
5.1 Accommodation . 8
5.2 Depth of field and depth of focus . 8
5.3 Accommodation-vergence mismatch . 11
6 Determination of the position of the 3D object on the non-physical screen . 11
6.1 General . 11
6.2 Parallax method . 12
6.3 Focal method . 14
6.4 Cylindrical lens . 15
6.5 Focal method – Angular dependence . 16
7 Summary . 18
Bibliography . 19

Figure 1 – Horopter . 5
Figure 2 – Horopter and Panum's fusional area (noted as the grey area) . 6
Figure 3 – The relation of IPD, distance and angle α and β . 7
Figure 4 – Depth of field and depth of focus . 9
Figure 5 – Effect of aperture size on depth of field . 10
Figure 6 – Accommodation-vergence mismatch where crossing point is inside the DOF . 11
Figure 7 – Parallax methods with and without LMD rotation . 13
Figure 8 – Example of experiment by the methods of IEC 62629-62-11 [8] . 13
Figure 9 – Principle of the focal method . 14
Figure 10 – Examples of the measured result of holographic 3D by the focal method. 14
Figure 11 – Refraction by non spherical lenses . 15
Figure 12 – Example of the light trajectories measurement through the pinhole plate . 17
Figure 13 – Light trajectories with azimuthal dependence . 18

Table 1 – Panum's area at the various viewing distances D . 8
A
Table 2 – Distinguishable depth and B at stereo acuity of 40 arc s . 8
∆D
D
Table 3 – Example of depth of field at the various viewing distances. 10
Table 4 – Lists of terms related to the distances in IEC documents . 12

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
3D displays -
Part 1-3: Generic - Human depth perception and the determination of the
position of 3D object on the non-physical screen

FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
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8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) IEC draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). IEC takes no position concerning the evidence, validity or applicability of any claimed patent rights in
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the latest information, which may be obtained from the patent database available at https://patents.iec.ch. IEC
shall not be held responsible for identifying any or all such patent rights.
IEC TR 62629-1-3 has been prepared by IEC technical committee 110: Electronic displays. It
is a Technical Report.
The text of this Technical Report is based on the following documents:
Draft Report on voting
110/1811/DTR 110/1818/RVDTR
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this Technical Report is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/publications.
A list of all parts in the IEC 62629 series, published under the general title 3D displays, can be
found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
– reconfirmed,
– withdrawn, or
– revised.
1 Scope
This part of IEC 62629, which is Technical Report, is intended to gather technical information
on human depth perception and the determination of 3D object positions on a non-physical
screen.
Clause 4 and Clause 5 describe the human depth perception and its threshold. This information
will be helpful in designing 3D displays of the non-physical screen type such as the possible
depth difference of 3D objects. In the measurement of the display, understanding the response
and limitation of the user is useful. Clause 4 and 5 provide such perception information in
determining the distance of 3D object on the non-physical screen.
It is not the intention of this document to set the requirement of the measurement system in
determining the position of 3D object on the non-physical screen.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 62629-1-2, 3D display devices - Part 1-2: Generic - Terminology and letter symbols
3 Terms, definitions and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the terms and definitions given in IEC 62629-1-2 apply.
ISO and IEC maintain terminology databases for use in standardization at the following
addresses:
– IEC Electropedia: available at https://www.electropedia.org/
– ISO Online browsing platform: available at https://www.iso.org/obp
3.2 Abbreviated terms
2D two dimensional
CMOS complementary metal–oxide–semiconductor
DOF depth of field
IPD interpupillary distance
LMD light measuring device
4 Perception of the depth by human
4.1 Horopter
Figure 1 a) illustrates an example where the image of points A and B is formed on the different
positions of the retina as L and L for the left eye and R and R for the right eye. The fovea
A B A B
is the central part of the retina, forming the site of the most distinct vision [1] . When L and
A
R are located on the fovea of each eye (L and R ), the direction of the eye toward the point
A F F
A is called the gazing direction, to distinguishing this direction from the other viewing direction.
L illustrates the distance from L and L . R illustrates the distance from R and R . When the

R F B R F B
sizes of L and R are the same, L and R are called corresponding retinal points.

R R B B
A horopter is the set of all points in a visual space that will stimulate pairs of corresponding
retinal points of the left and right eyes [1]. A person perceives the points on the horopter to be
at the same distances. The shapes of the experimentally measured horizontal horopter change
from the concave to the planar to the convex as the distance increases, as illustrated in Figure 1
[1].
a) Fovea, horopter and corresponding retinal b) Shapes of the experimentally measured
points horizontal horopter versus the viewing distance
Figure 1 – Horopter
___________
Numbers in square brackets refer to the Bibliography.
4.2 Panum's fusional area
Figure 2 – Horopter and Panum's fusional area (noted as the grey area)
Panum's fusional area is the area surrounding the horopter where the binocular fusion is
possible as illustrated in Figure 2. When two eyes gaze on the point A, the image of A is formed
on the fovea of each eye and the horopter for the point A exists along the line passing through
the point A. In Figure 2, α is the angle between the two lines that connect the point A and the
image of the point A formed of each eye. Similarly, the image of the point B is formed on the
retina of each eye and β is the angle between the lines that connect the point B and the image
of the point B formed of each eye. The angle between the two lines that connect a specific point
and the image of this specific point formed of each eye is called the binocular parallax. The
difference between α and β, (α – β) is called the binocular disparity. The difference between the
left and right images of the 3D display is also called binocular disparity. In this document, the
former is called angular binocular disparity and the latter is called spatial binocular disparity to
avoid confusion.
If the point B is also on the horopter, the sizes of α and β are the same and the angular binocular
disparity is zero. (α – β) increases as B is farther from the horopter. When B is inside Panum's
fusional area, a fused stereoscopic image is perceived. When B is outside Panum's fusional
area, fused stereoscopic is not possible and double vision occurs. The size of Panum's fusional
area is reported to be 5 arc min to 20 arc min for the object whose image is formed at the fovea
of the eye and to be larger at other directions [4]. The size of the visual field of the binocular
vision is 120° and stereoscopic depth can only be perceived within this range of the visual field.
4.3 Stereo acuity
Stereo acuity is the minimum value of angle (α – β) at which a person can identify the depth
difference. Stereo acuity of people of normal stereoscopic vision is typically less than 10 arc s.
For the larger stereo acuity, the ability to identify the depth difference deteriorate. In clinical
tests, a threshold of 40 arc s is typically used as 95 % of total population has stereo acuity
better than this value [1].
4.4 Panum's fusional area and stereo acuity represented in length

Figure 3 – The relation of IPD, distance and angle α and β
Panum's fusional area and stereo acuity are typically reported in angles while the values in the
unit of the length are sometimes practically useful for the display application. From the values
in the unit of angle, the values of Panum's fusional area and stereo acuity in the unit of length
can be calculated. The relation of D , the distance D , D and angle α, β of Figure 3 can be
IPD A B
written as
D

IPD


(1)
α 2

tan =
D
2 A
DD
 
IPD IPD
 
 
22 (2)
β
 
tan
D DD+∆
( )
2 B
A
When the viewing distance D is much larger than D , the tangent function can be
A IPD
approximated as tan(α/ 2) ≈ (α/ 2) and tan(β/ 2) ≈ (β/ 2). The difference between two angles can
be approximated as
DD
α β αβ−∆11 D
IPD IPD
tan− tan≅ −
 (3)
2 22 2 D D 2 DD +∆D
( )
A B AA
Table 1 shows the example of the nearest and the farthest boundaries of Panum's fusional area
at 5 arc min and 20 arc min at the viewing distances of 1 m, 2 m, 5 m and 10 m.
= =
==
Table 1 – Panum's area at the various viewing distances D
A
Viewing distance 1 m 2 m 5 m 10 m
Panum's area at 5 arc min 0,98 m to 1,02 m 1,92 m to 2,09 m 4,49 m to 5,64 m 8,17 m to 12,9 m
Panum's area at 20 arc min 0,92 m to 1,10 m 1,69 m to 2,44 m 3,45 m to 9,05 m 5,27 m to 95 m

Table 2 shows the smallest distinguishable depth ∆D at the stereo acuity of 40 arc s. To induce
such an amount of depth perception, the images seen by the left and right eye are different. If
this difference is induced by spatial binocular disparity, spatial binocular disparity B can be
D
written as Formula (4) using the triangle similarity theorem.
∆D
BD=
D IPD (4)
DD+∆
( )
A
Once ∆D is calculated at the specific condition of the stereo acuity and the viewing distance,
the necessar
...