First, measuring instruments
3D/2D movie screen digital brightness meter directly displayed with fL reading (or digital brightness meter with cd/m2 reading resistant to infrared and radio frequency interference not exceeding 2°), tripod, digital color temperature meter, THX Blue filter glasses, Super HiVi CAST and DVE-HD Blu-ray Disc.
Second, the optical index of the projection system
Curtain center brightness
The GB/T 21048-2007 national standard measures the brightness of the movie screen center. The tripod is used to erect the brightness meter at a height of 1.0 m from the center of the seating area of ​​the auditorium.
Guangfa Jizi [2004] No. 1036 "Temporary Technical Requirements for Film Digital Screening" requires that the brightness meter should be placed in the center of the audience of the audience in the measurement, and the distance from the screen is 1.5 to 3.5 times. Within the range, the height from the ground on the longitudinal centerline of the auditorium is 1.1m.
Previously, 2D private cinema screen center brightness was not tested separately, usually with color sensors and CalMAN or HCFR software for additional results after color adjustment.
However, for 3D private theaters, if the 3D glasses are placed in front of the chroma sensor to measure the brightness, there will be a large error, because the 3D glasses are not easy to fix in front of the chroma sensor; the second is the home 3D projector. Most active shutter glasses that use infrared transmission sync signals are attached to the front of the screen together with the chrominance sensor to measure the error that is often not received by the sync signal. Third, the high gain screen causes errors due to the different angles of the reflected light from the screen.
Therefore, the requirements of the specification clause 4.1.2 for the brightness measurement point of the screen center refer to the test method of the cinema. The measurement is carried out with a tripod to mount the brightness meter in the center of the theater room, and the distance from the screen is 2.0 to 3.5 times. Within the high length range, the height from the ground on the longitudinal centerline of the AV room is 1.0m~1.1m.
When measuring, first open the device under test and all test instruments, and warm up for not less than 20 minutes.
In the sixth paragraph of the Super HiVi CAST Blu-ray Disc video test image, there is no difference between the projector's brightness output limit state of 107% ultra-white and 100% pure white, and 100% pure white and 95% white.
Point the brightness meter at the center of the screen, observe the screen through the brightness meter viewfinder or eyepiece and adjust the focal length of the brightness meter objective to clear. Continue reading for 3 seconds to 5 seconds. Read the measured value. This value is the 2D screen center brightness.
Turn the projector or Blu-ray player 2D to 3D function, play the above test image to see the left and right screen overlap on the screen, use the active shutter 3D glasses to turn on the power, and put on the 3D glasses to confirm the overlap of the screen and have a three-dimensional sense, then Hold the 3D glasses in front of the brightness meter for 3 seconds to 5 seconds. The left and right lenses are measured separately. At least 2 pairs of 3D glasses are measured. The measured values ​​are read and averaged. The average value is the 3D screen center brightness.
2. Reflective color temperature of the screen
The GB/T 21048-2007 national standard measures the reflective color temperature of the movie screen by placing the color temperature meter at 1.0m directly in front of the screen and facing the screen.
Guangfa Jizi [2004] No. 1036 "Temporary Technical Requirements for Film Digital Screening" requires that the measurement point of CIE chromaticity coordinates be close to the screen.
Specification Clause 4. 2. 1 The requirement for the screen color temperature measurement point is to place the color temperature meter 0.3m in front of the screen and face the screen.
When measuring, adjust the brightness of the center of the screen to the range specified in the specification 3.3.1.
Play the 30 IRE~80 IRE grayscale window image and 100 IRE white window image of the DVE test disc.
Turn on the color temperature meter power switch, put the measurement mode in the color temperature measurement state, place the color temperature meter 0.3m in front of the screen and face the screen. Maintain this state for more than 3 seconds. Press the measurement data lock button to record 30 IRE respectively. ~80 IRE grayscale, 100 IRE white color temperature measurement data.
The reflective color temperature of the screen when passing through the 3D glasses when the device is operating in the 3D mode is measured.
The reflective color temperature of the screen 2D and 3D modes of the projection device is measured.
3. Screen reflective black level
In the eighth paragraph of the Super HiVi CAST Blu-ray Disc video test image, when the black level is correct, there is no difference between the super black and the 0% pure black in the middle of the image, and 0% pure black and 1% black are different.
Visual observation of the screen reflection black level when the projection device is operated through the 3D mode through the 3D glasses.
It must be observed by not less than 3 inspectors.
4. Reflective shades of the screen
Play the 14th paragraph of the Super HiVi CAST Blu-ray Disc video test image, and insert the THX blue filter glasses with the naked eye. When the color tone is correct, the cyan and magenta squares should be mixed into one whole picture. And can't see the difference.
Visual observation of the reflective color of the screen when the projection device is working in 3D mode through the 3D glasses. Before the observation, the inspector must wear the THX blue filter glasses and then wear the 3D glasses.
It must be observed by not less than 3 inspectors.
5. Screen reflective color (color saturation)
Play the 16th blue + gray square image of the Super HiVi CAST Blu-ray Disc video test image, wear the THX blue filter glasses and observe with the naked eye. When the color (color saturation) is correct, the blue and gray squares should be Mixed into a whole picture without seeing the difference.
Visual observation of the reflective color saturation of the screen when the projection device is working in 3D mode through the 3D glasses. Before the observation, the inspector must wear the THX blue filter glasses and then wear the 3D glasses.
It must be observed by not less than 3 inspectors.
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