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DY/T 8-2023: Technical requirements and measurement methods for digital cinema LED auditorium
DY/T 8-2023
DY
FILMDOM STANDARD OF THE
PEOPLE?€?S REPUBLIC OF CHINA
ICS 37.060.99
CCS N40
Technical requirements and measurement methods for
digital cinema LED auditorium
ISSUED ON. NOVEMBER 20, 2023
IMPLEMENTED ON. NOVEMBER 20, 2023
Issued by. State Film Administration
Table of Contents
Foreword... 3
1 Scope... 4
2 Normative references... 4
3 Terms and definitions... 4
4 Abbreviations... 5
5 Composition of digital cinema LED auditorium... 5
6 Technical requirements... 6
7 Measurement method... 8
7.1 Measurement equipment... 8
7.2 Measurement signal... 10
7.3 Measurement environment and measurement conditions... 15
7.4 Measurement steps... 17
References... 28
Technical requirements and measurement methods for
digital cinema LED auditorium
1 Scope
This document specifies the optical and acoustic technical requirements and
corresponding measurement methods for digital cinema LED auditoriums.
This document applies to the operation and maintenance, testing and certification,
quality supervision, technical management and installation, commissioning, acceptance
of relevant equipments of digital cinema LED auditoriums.
2 Normative references
The contents of the following documents constitute essential clauses of this document
through normative references in the text. Among them, for dated references, only the
version corresponding to that date applies to this document; for undated references, the
latest version (including all amendments) applies to this document.
GY/T 311-2017 Technical requirements and methods of measurement of audio-
visual environment for cinema
GY/T 312-2017 Cinematography - B-chain electro-acoustic response of motion-
picture control rooms and indoor theatres - Specifications and measurements
3 Terms and definitions
The following terms and definitions apply to this document.
3.1
Digital cinema LED projection system
A system used to realize digital movie program decoding and playback and LED
digital projection, which is mainly composed of digital movie playback server, LED
controller, LED display screen, sound reproduction system.
3.2
Digital cinema LED auditorium
An auditorium that uses a digital cinema LED projection system for movie
projection.
3.3
Electro-optic transfer characteristic
The relationship between the input code value and the display brightness of the LED
display, which is expressed by a characteristic value.
3.4
Stereoscopic extinction ratio
The ratio -- of the left eye (right eye) image brightness to the crosstalk light and
ambient light, which is used to measure the left eye (right eye) image brightness's
immunity to crosstalk light and ambient light.
4 Abbreviations
The following abbreviations apply to this document.
HDR. High Dynamic Range
LED. Light-Emitting Diode
SDR. Standard Dynamic Range
5 Composition of digital cinema LED auditorium
The digital cinema LED auditorium consists of a digital cinema LED projection system
and other auxiliary systems. The digital cinema LED projection system mainly consists
of a digital cinema playback server, an LED controller, an LED display screen, a sound
reproduction system, as shown in Figure 1.
- Receiving angle. ??? 1??;
- Accuracy. ??? ??2%.
7.1.4 Spectroradiometer
The spectroradiometer shall meet the following requirements.
- Wavelength range. 380 nm ~ 780 nm;
- Measurement bandwidth. ??? 2.5 nm ~ 20 nm;
- Receiving angle. ??? 1??;
- Chromaticity accuracy x, y. ??? ??0.002.
7.1.5 Reflectivity tester
The reflectivity tester shall meet the following requirements.
- It can measure specular reflectivity and diffuse reflectivity;
- Illumination. d/8 integrating sphere structure (diffuse illumination);
- Integrating sphere size. ??? ??54 mm;
- Light source. Pulse xenon lamp, quantity ??? 2, can simulate standard illuminants A,
C, D50, D65, etc.;
- Wavelength range. ??? 360 nm ~ 740 nm;
- Reflectivity measurement range. ??? 0% ~ 175%;
- Display resolution. 0.01.
7.1.6 Noise signal generator
It shall meet the requirements of 5.2.4 of GY/T 311-2017.
7.1.7 Measurement microphone
It shall meet the requirements of 5.2.5 of GY/T 311-2017.
7.1.8 Sound level meter
It shall meet the requirements of 5.2.6 of GY/T 311-2017.
7.1.9 Filter
It shall meet the requirements of 5.2.7 of GY/T 311-2017.
7.2.2.2 HDR
Measurement signal with signal encoding value (X' = 2524, Y' = 2546, Z' = 2583).
7.2.3 Black field measurement signal
7.2.3.1 SDR
Measurement signal with signal encoding value (X' = 122, Y' = 128, Z' = 125).
7.2.3.2 HDR
Measurement signal with signal encoding value (X' = 60, Y' = 62, Z' = 65).
7.2.4 Red field measurement signal
7.2.4.1 SDR
Measurement signal with signal encoding values (X' = 2901, Y' = 2171, Z' = 100).
7.2.4.2 HDR
Measurement signal with signal encoding values (X' = 2234, Y' = 1925, Z' = 68).
7.2.5 Green field measurement signal
7.2.5.1 SDR
Measurement signal with signal encoding values (X' = 2417, Y' = 3493, Z' = 1222).
7.2.5.2 HDR
Measurement signal with signal encoding values (X' = 1988, Y' = 2387, Z' = 1327).
7.2.6 Blue field measurement signal
7.2.6.1 SDR
The measurement signal with signal encoding value (X' = 2014, Y' = 1416, Z' = 3816).
7.2.6.2 HDR
The measurement signal with signal encoding value (X' = 1871, Y' = 1525, Z' = 2565).
7.2.7 ?€?Black to white?€? grayscale measurement signal
7.2.7.1 SDR
The measurement signal is divided into 10 groups of images. The signal encoding value
requirements are as shown in Table 3.
a) Ambient temperature. 15 ??C ~ 35 ??C;
b) Relative humidity. 10% ~ 90%;
c) Atmospheric pressure. 86 kPa ~ 106 kPa;
d) Voltage amplitude. 220 V ?? 10 V AC;
e) Nominal frequency. 50 Hz.
7.3.2 Measurement conditions
The measurement conditions are as follows.
a) All measurements shall be carried out in the normal viewing environment of the
auditorium;
b) All equipment shall be in normal and stable working state, or configured
according to the measurement requirements;
c) All measurement signals shall be played and output to the LED display screen by
the digital movie playback server;
d) The measurement of the optical system should be carried out within the range of
qualified color reproduction at the center of the LED display screen;
e) When measuring the optical system, it shall be carried out after the light output of
the LED display screen is stable (thermal stabilization time is not less than 20
minutes) and the stereo projection equipment is stable (stereo projection
equipment is exposed to light for not less than 15 minutes);
f) When measuring the optical system, the optical measuring instrument is set up at
the center of the seating area of the auditorium, 1.15 m above the selected seat
floor; the measuring lens is aimed at the center of the LED display screen and has
a clear focus;
g) When measuring the stereo projection optical system, the stereo glasses are placed
horizontally in front of the lens of the optical measuring instrument; the lens shall
be perpendicular to the measurement axis and not block the instrument
measurement;
h) After each time the acoustic measurement equipment is turned on, the system shall
be calibrated before the corresponding acoustic measurement can be carried out;
i) When measuring the projection acoustic system, the measurement microphone is
set up at a height of 1.15 m from the selected seat floor in the auditorium seating
area. The measurement microphone points to the screen and tilts upward at a 45??
angle. If the measurement microphone is lower than the seat back height, the
measurement microphone shall be appropriately raised and exceed the seat back
height by about 0.15 m;
j) When measuring the projection acoustic system, the spectrum
analyzer/reverberation time meter shall be placed outside the auditorium to be
measured, to avoid the noise emitted by the measuring instrument itself affecting
the measurement results; at the same time, avoid artificial noise in the auditorium
to affect the measurement results.
7.4 Measurement steps
7.4.1 Display resolution
The measurement steps are as follows.
a) Projection resolution measurement signal;
b) Check whether the pixels of the LED display screen and the pixels of the
measurement signal correspond one by one; meanwhile it can fully display the
received image signal.
7.4.2 Center point brightness
The measurement steps are as follows.
a) Turn on the spectroradiometer;
b) Project the white field measurement signal;
c) Measure and record the white field center point brightness value of the LED
display;
d) Measure and record the white field center point brightness value of the LED
display, at the center seats of the first and last rows of the audience area, and the
leftmost and rightmost seats of the middle row.
7.4.3 Full screen brightness mean
The measurement steps are as follows.
a) Turn on the imaging brightness meter;
b) Project the white field measurement signal;
c) Measure and record the full screen brightness mean of the LED display.
7.4.4 Brightness uniformity (module)
The measurement steps are as follows.
7.4.9.1 SDR electro-optical conversion characteristics
The measurement steps are as follows.
a) Turn on the spectroradiometer;
b) Display the "black to white" grayscale measurement signal and the "black to dark
gray" grayscale measurement signal, respectively;
c) Measure the brightness value of the center point of each grayscale;
d) Use the least squares method to fit the curve power value between the image signal
encoding value and the image brightness value, which is gamma.
7.4.9.2 HDR electro-optical conversion characteristics
The measurement steps are as follows.
a) Turn on the spectroradiometer;
b) Project the "black to white" grayscale measurement signal and the "black to dark
gray" grayscale measurement signal, respectively;
c) Measure the brightness value of the center point of each grayscale;
d) Calculate the percentage -- of the measured brightness value of each grayscale
center point TO the reference output brightness Y corresponding to the grayscale
measurement signal encoding value in Table 4 and Table 6.
7.4.10 Brightness of the center point of stereoscopic projection
The measurement steps are as follows.
a) Turn on the spectroradiometer;
b) Set the LED display screen to stereoscopic projection mode; use stereoscopic
projection equipment;
c) Display white field measurement signals for both eyes at the same time;
d) Measure the brightness value of the left eye white field center point ???????? and the
brightness value of the right eye white field center point ????????, through the left and
right lenses of the stereo glasses, respectively;
e) Calculate and record the brightness of the stereoscopic projection center point ????
of the LED display screen according to formula (3);
b) Set the LED display screen to stereo projection mode; use stereo projection
equipment;
c) Display the white field signal to the left and right eyes at the same time;
d) Measure and record the white field chromaticity coordinates of the stereo
projection center point of the LED display screen, through the left and right lenses
of the stereo glasses, respectively.
7.4.14 Extinction ratio of stereoscopic projection
The measurement steps are as follows.
a) Turn on the spectroradiometer;
b) Set the LED display to stereoscopic projection mode; use stereoscopic projection
equipment;
c) Project the white field measurement signal to the left eye; project the black field
measurement signal to the right eye;
d) Through the left lens of the stereo glasses, measure and record the brightness value
of the center point of the white field ;
e) Through the right lens of the stereo glasses, measure and record the brightness
value of the center point of the black field ;
f) Project the black field measurement signal to the left eye; project the white field
measurement signal to the right eye;
g) Through the left lens of the stereo glasses, measure and record the brightness value
of the center point of the black field ;
h) Through the right lens of the stereo glasses, measure and record the brightness
value of the center point of the white field ;
i) Calculate and record the left eye's stereoscopic projection extinction ratio ????????
according to formula (7);
Where.
7.4.15.2 Specular reflectivity
The measurement steps are as follows.
a) Turn off the LED display;
b) Use a reflectivity tester to measure close to the LED display;
c) The measurement shall be carried out at multiple locations on the LED display;
d) Calculate the average value of all measurement results for each wavelength; draw
a specular reflectivity average curve;
e) Record the worst value of the specular reflectivity of the LED display, as the
specular reflectivity measurement result.
7.4.16 Pixel visibility
The measurement steps are as follows.
a) Project the resolution measurement signal;
b) Check in the first row of seats, to see if the pixel structure of the LED display and
the obvious dark area between pixels can be observed.
7.4.17 Image zoom
The measurement steps are as follows.
a) Project the resolution measurement signal;
b) Check in the first row of seats, to see if the image scaling artifacts of the LED
display can be observed.
7.4.18 Sub-pixel spatial consistency
The measurement steps are as follows.
a) Project the resolution measurement signal;
b) Check in the first row of seats, to see if the geometric anomalies of the sub-pixel
spatial arrangement of the LED display, such as edge or chessboard artifacts, can
be observed.
7.4.19 Spatiotemporal aliasi...