IEC 62977-3-6:2025

IEC 62977-3-6 ®
Edition 1.0 2025-06
INTERNATIONAL
STANDARD
Electronic displays –
Part 3-6: Evaluation of optical performance – Spatial resolution
ICS 31.120; 31.260 ISBN 978-2-8327-0456-1

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– 2 – IEC 62977-3-6:2025 © IEC 2025
CONTENTS
FOREWORD . 4
INTRODUCTION . 6
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, abbreviated terms, letters and symbols. 7
3.1 Terms and definitions . 7
3.2 Abbreviated terms. 8
3.3 Letters and symbols . 8
4 Standard measuring equipment . 9
4.1 General . 9
4.2 Equipment . 9
4.2.1 Digital pattern generator . 9
4.2.2 Imaging LMD . 10
5 Standard measuring conditions . 11
5.1 Standard measuring environmental conditions . 11
5.2 Standard measuring darkroom conditions . 11
5.3 Measurement locations on the screen . 11
5.4 Input signal condition . 12
6 Display contrast modulation measurement . 12
6.1 General . 12
6.2 Contrast modulation . 12
6.3 Measuring method with grille pattern . 12
6.4 Spatial resolution evaluation using contrast modulation . 15
7 Display MTF measurement . 16
7.1 General . 16
7.2 MTF concept for sampled imaging systems . 17
7.3 Line-based method . 17
8 Reporting . 20
Annex A (informative) Evaluation of spatial resolution . 21
Annex B (normative) Edge-based LMD MTF measurement. 22
Annex C (informative) Precautions for spatial resolution measurement methods . 24
C.1 Sampling issues in grille pattern luminance contrast measurement method . 24
C.2 Constraints of the grille pattern luminance contrast and the line-based MTF
measurement methods . 24
C.3 Colour evaluation . 25
Annex D (informative) Example of line-based MTF evaluation . 26
Annex E (informative) Constraints on curved panel evaluation . 29
Bibliography . 30

Figure 1 – Diagram of DUT and measurement system . 10
Figure 2 – Example of nine measurement locations on DUT screen . 11
Figure 3 – Input signal image for grille pattern . 13
Figure 4 – Grille pattern examples of signal image on DUT screen . 13
Figure 5 – Example of luminance profile . 14
Figure 6 – Evaluation of contrast modulation measurement . 16

Figure 7 – Schematic of the display MTF measurement setup . 17
Figure 8 – Intermediate results obtained at different points in the MTF measurement
process . 19
Figure A.1 – Example image of luminance profile . 21
Figure B.1 – Schematic of the edge-based LMD MTF measurement setup . 22
Figure B.2 – Flow diagram of the edge-based LMD MTF measurement process . 23
Figure C.1 – Examples of display physical sub-pixel arrangements . 25
Figure D.1 – Computer-generated 200 (W) × 200 (H)-pixel images of a vertical line
displayed on the screen with the RGB-stripe array having the MTF of
|sinc(ξ , ξ )| for pixel ratios of 2 and 7 . 26
x,LMD y,LMD
Figure D.2 – RGB stripe arrangement: Layout of the micro-colour-filter array and
vertically averaged luminance profile . 26
Figure D.3 – Reference display MTF . 27
Figure D.4 – Flowchart of the algorithm for the line-based display MTF measurement . 27
Figure D.5 – Slanted line image captured by LMD (left) and obtained LSF (right) . 28

Table 1 – Symbols in this document . 9

– 4 – IEC 62977-3-6:2025 © IEC 2025
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRONIC DISPLAYS –
Part 3-6: Evaluation of optical performance – Spatial resolution

FOREWORD
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IEC 62977-3-6 has been prepared by IEC technical committee 110: Electronic displays. It is an
International Standard.
The text of this International Standard is based on the following documents:
Draft Report on voting
110/1752/FDIS 110/1769/RVD
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 International Standard 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 62977 series, published under the general title Electronic 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.
– 6 – IEC 62977-3-6:2025 © IEC 2025
INTRODUCTION
Historically, the size of a scanned dot drawn on a cathode-ray tube display with an electron
beam was the main contributor to the display spatial resolution. Later, the pixel geometry of a
conventional flat-panel display with red, green and blue (RGB) colour-filter elements in each
pixel, such as RGB stripes, provides a simple metric to accurately estimate the display
resolution. However, some recent display technologies use other subpixel arrangements or
additional subpixel colours to render each incoming image pixel, thereby obscuring the pixel
count, and the subpixel rendering affects the spatial performance of the display. Furthermore,
the optical elements used in the display structure affect the spatial imaging performance. For
example, a diffusing film can be overlaid on the front surface of a panel to improve the viewing
direction performance and reduce the specular reflection of ambient light. However, such front
surface diffusers generate optical interpixel crosstalk and sparkle, which degrade the spatial
resolution characteristics of the display. Therefore, the spatial imaging performance of a display
is typically not solely determined by the pixel count.
It is important for an effective metrological method to be technologically agnostic and
independent of the device architecture. Therefore, the pixel used in the spatial frequency unit
of cycles/pixel can be logically defined by the standard image format of the input/output signal
and not by the physical pixel structure of the device. The unit of the spatial frequency is based
on the sampling grid interval standardized in the image format used in the display input signal.
NOTE The ITU Radio communication Sector (ITU-R) defined the pixel count and sampling lattice for 4K and 8K
UHD formats in recommendation BT.2020 [1] .
The spatial resolution characteristics indicate spatial imaging performance of a display by
evaluating the reproduction of input digital images by the display.
There are two measurement methods covered in this document. The first method involves
measuring the contrast based on the display response of an alternating line pair input, and the
second method involves a line-based modulation transfer function (MTF) measurement. Both
measurement results show the spatial resolution characteristics of the flat panel display
(see Annex E) as a function of spatial frequency.

___________
Numbers in square brackets refer to the Bibliography.

ELECTRONIC DISPLAYS –
Part 3-6: Evaluation of optical performance – Spatial resolution

1 Scope
This part of IEC 62977 specifies the measuring and evaluation methods of spatial resolution of
flat panel emissive displays, by determining their contrast modulation and modulation transfer
function (MTF).
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 cited edition applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
ISO 12233, Photography – Electronic still picture imaging – Resolution and spatial frequency
responses
3 Terms, definitions, abbreviated terms, letters and symbols
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions 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
3.1.1
Michelson contrast
ratio of the luminance amplitude of a periodic pattern, such as grille pattern, to the average
luminance
3.1.2
grille pattern
alternating straight line-pair pattern of a white line (or a colour line) and a black line with equal
width
3.1.3
contrast modulation
grille pattern luminance contrast
Michelson contrast of the moving-window-average luminance profile of a grille pattern displayed
on a screen
3.1.4
modulation transfer function
magnitude response of an optical system to sine wave of different spatial frequencies

– 8 – IEC 62977-3-6:2025 © IEC 2025
3.1.5
pixel ratio
square-grid spatial sampling interval ratio of the device under test (DUT) input image to the
light measuring device (LMD) output image, when the DUT screen is captured by the LMD at a
specific magnification
Note 1 to entry: “magnification" in this document is “lateral magnification” in optical engineering field.
Note 2 to entry: LMD pixel grid assumed to be square in this document.
3.1.6
spatial resolution
spatial imaging performance of a display by evaluating the detail reproduction of input digital
image by the display
3.2 Abbreviated terms
APL average picture level (see IEC 62977-2-1 [2])
DUT device under test
ESF edge spread function
LMD light measuring device
LSF line spread function
MTF modulation transfer function
MWA moving-window average
RGB red, green, blue
ROI region of interest
3.3 Letters and symbols
The symbols used in this document are tabulated as Table 1.

Table 1 – Symbols in this document
Symbol Units Definition
C
- threshold value to estimate display resolution
T
C
- contrast modulation or grille pattern luminance contrast
M
-2
L
cd·m luminance of the average value for all maxima
W
-2
L
cd·m luminance of the average value for all minima
K
w window size used for MWA
function to output the LMD pixel location number at nth peak luminance
pixelN (n)
-
LMD
maximum
n
- estimated number of resolvable lines
r
δ - estimated display resolution from grille pattern luminance contrast method
9-point average of estimated display resolution from grille pattern luminance
δ
-
a
contrast method
ξ cycles/pixel
LMD spatial frequency
LMD LMD
ξ cycles/pixel
display spatial frequency
DISP DISP
m - pixel ratio
N
- number of bins
bin
d pixel /N
bin width
bin LMD bin
LSF
- overall LSF of the LMD and display
OA
MTF
- display MTF value
DISP
MTF
- MTF value of the LMD
LMD
MTF
- overall MTF
OA
NOTE ‘pixel ‘ is a spatial sampling interval defined in the image format of the output signal of the LMD, and
LMD
‘pixel ’ is a spatial sampling interval defined in the image format of the input signal of the DUT.
DISP
4 Standard measuring equipment
4.1 General
The measurement shall be conducted under a darkroom condition. Figure 1 shows a diagram
of the DUT and the measurement system. The DUT shall be driven by an RGB signal from a
digital pattern generator. The displayed image on the display screen is captured by an imaging
LMD. The optical axis of the LMD shall be coincident with the surface normal to the region of
interest (ROI).
4.2 Equipment
4.2.1 Digital pattern generator
The digital pattern generator shall generate a required image signal for the DUT.
NOTE Any device that generates the digital signal can be used

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4.2.2 Imaging LMD
The imaging LMD shall capture the displayed image at an appropriate exposure time. The LMD
should be used within its linear range for the measuring luminance and should use a spectral
mismatch correction to CIE standard spectral luminous efficiency function for photometric vision
or should have a f ʹ value of at least 6 % [3].
If the light output of the display is temporally modulated, then the LMD integration time should
be synchronized with the vertical frame synchronization signal. If the LMD is not capable of
synchronizing, then the LMD integration time shall include at least 200 frames (refer to IDMS
ver.1.2, Appendix A, 4.2.2[4]).
LMD should be set perpendicular to the DUT screen as results can be different when measuring
from another viewing direction (vantage point direction).

Figure 1 – Diagram of DUT and measurement system

5 Standard measuring conditions
5.1 Standard measuring environmental conditions
Measurements should be carried out under the standard environmental conditions:
– Temperature: 25 °C ± 3 °C,
– Relative humidity: 25 % RH to 85 % RH,
– Atmospheric pressure: 86 kPa to 106 kPa.
When different environmental conditions are used, they shall be noted in the measurement
report.
5.2 Standard measuring darkroom conditions
The luminance due to unwanted ambient light reflected off the screen of the DUT shall be less
than 1/20 of the display’s black state luminance. The amount of reflected ambient light shall be
measured by turning off the display. If this condition is not satisfied, then the method of
subtracting the background luminance from the total luminance, or a stray light elimination tube
[5] should be used, and it shall be reported.
NOTE Even in darkroom condition, stray light in the LMD, which originates from the emitted light of the display can
falsely decrease the measured resolution [6]. In the slanted line MTF method, scattered light in the LMD is corrected
in 7.3, item g).
5.3 Measurement locations on the screen
The spatial resolution of the DUT can be measured at different areas on the display screen.
The nine measurement locations are shown in Figure 2 [2]. The screen centre is indicated as
P . If different locations are used, their coordinates shall be reported.
Figure 2 – Example of nine measurement locations on DUT screen

– 12 – IEC 62977-3-6:2025 © IEC 2025
5.4 Input signal condition
Because the input signal phase is important for evaluating spatial resolution, several columns
of signal pixels are presented in the horizontal or vertical direction of the input signal format.
For example, 3 840 columns are presented in a 4K horizontal signal format. The columns are
numbered from 1 through 3 840. Odd columns are denoted 1, 3, 5, …, 3 839: when they
represent high ‘odd’ pixel signals, that is called odd phase. Even columns are denoted 2, 4,
6, …, 3 840 and represent high ‘even’ pixel signals, which is called even phase. Depending on
the use of ‘odd’ or ‘even’ pixel signals, the evaluation results can be different because of the
relation between the signal and display pixel phases. An input signal of both even and odd
phases shall be used for spatial resolution evaluation. This document is intended for spatial
resolution measurements of DUTs that can be specified with measurement results of those the
even and odd signal inputs (see Annex C.2).
To avoid the influence of average picture level (APL) limit of the DUT, particularly on the grille
pattern for 9-point contrast modulation evaluation, the window size should be less than 4 % of
the DUT screen.
6 Display contrast modulation measurement
6.1 General
In Clause 6, the measurement of contrast modulation (i.e. the spatial resolution measurement
using grille patterns) is described. The resolution capabilities of a display are evaluated based
on a threshold contrast modulation of the grille patterns.
6.2 Contrast modulation
The addressability is the number of pixels that can be separately and adequately controlled.
Contrast modulation evaluates the ability of a display to render line-pair patterns. The resolution
can be defined as the number of alternating black and white lines that can be displayed with a
stated minimum contrast modulation (i.e. the threshold contrast modulation C ).
T
In the measurement, the phase of the grille shall be changed from ‘odd’ phase to ‘even’ phase
by changing the input signal of the grille pattern. After the grille pattern phase is switched,
another contrast modulation value C shall be calculated using the same procedure as the first
M
C value. The C shall be reported for both phases, as well as the averages of the two C
M M M
values.
LL−
W K
C =
(1)
M
LL+
WK
where
L and L are the luminance of the average value for all maxima and minima with moving-
W K
window average (MWA), respectively.
6.3 Measuring method with grille pattern
Set the digital pattern generator to output the targeted resolution, such as 3 840 pixels by 2 160
pixels, and set the pattern generator to output grille pattern signal at the measurement location,
which pattern constructs vertical or horizontal lines of black and white, or any colour to be
measured instead of white, as one signal pixel by one signal pixel respectively. An example of
the input signal is shown in Figure 3, and examples of displayed grille patterns are shown in
Figure 4.
NOTE High signal (and low signal) count is set to half of input resolution count.
Figure 3 – Input signal image for grille pattern

a) Vertical white-black grille pattern b) Horizontal white-black grille pattern

c) Grey-black grille patterns d) Green-black grille patterns

e) Red-black grille patterns f) Blue-black grille patterns

NOTE The pattern can be horizontal or vertical with white, grey, or colour grille. All the patterns are shown in odd
phase.
Figure 4 – Grille pattern examples of signal image on DUT screen
The luminance distribution across the grille pattern is obtained from an image captured by the
imaging LMD. The sampling rate or pixel ratio is recommended to be an integer greater than or
equal to 30 (refer to IDMS ver.1.2, section 7.2 [4]). For further details, see Annex C.1.
Optionally a grey grille pattern, which has lower high peak signal input level, or colour grille
pattern can be used (see Annex C.3).

– 14 – IEC 62977-3-6:2025 © IEC 2025
An example of a one-dimensional (1D) luminance profile is shown in red in Figure 5. This
example shows a set comprising three successive peaks as a consequence of the physical
display pixel structure of the RGB stripe.

NOTE An example of luminance profile (integration along the vertical grille lines) is shown in red. The moving-
window average is shown in blue [4].
Figure 5 – Example of luminance profile
Use the MWA filtering method to obtain maxima L and minima L to calculate C value as
W K M
described below.
a) Perform MWA processing to the 1D profile to es
...