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Research Areas

OUTLINE
1.1 Super Hi-Vision research
1.1.1 Super Hi-Vision format
1.1.2 Super Hi-Vision equipment
1.1.3 Super Hi-Vision satellite transmission
1.1.4 Super Hi-Vision optical time-division multiplexed transmission
1.1.5 SHV coding

1.2 Three-dimensional television research
1.2.1 Integral 3D television
1.2.2 Capture and reproduction of 3D images

1.3 High-presence audio systems research
1.3.1 3D Audio
Contents

1.1.1

Super Hi-Vision format




Super Hi-Vision (SHV) is currently being developed based on the specifications shown in Table 1, but we are also studying optimizations of parameters such as the number of pixels, the frame rate and colorimetry (chromaticity coordinates for the three primary colors and standard white). SHV video is standardized in Recommendation ITU-R BT.1769, "Expanded Large Screen Digital Imagery (LSDI)", and SMPTE 2036-1, "Ultra High Definition Television (UHDTV)", but parameters other than the number of pixels (7680 pixels by 4320 rows) are the same as the values for Hi-Vision (HDTV).

Table 1. Super Hi-Vision specifications
Number of pixels
7680 X 4320
Aspect ratio
16:9
Design viewing distance
(H is screen height)
0.75H
Field-of-view at the design
viewing distance (horizontal plane)
100°
Frame rate
60 Hz progressive scan
Colorimetry
ITU-R recommendation BT.1361
Audio system
22.2ch

During FY2009, we focused our research on colorimetry and the frame rate so that the results of research would be reflected in values for each parameter.

Colorimetry

We selected the following three principal requirements for the colorimetry parameters and studied colorimetry systems that would satisfy them.

(1) It must encompass the color gamut of existing systems, including Hi-Vision, and include real surface colors to the largest extent possible.
(2) All colors handled by the colorimetry system must be monitorable on a display that is practical to implement.
(3) The number of primary colors used should be balanced with the cost of a television system.

From these conditions, we settled on a colorimetry system providing a wide color gamut with three primary colors at chromaticity coordinates for R, G, and B equivalent to monochromatic light with wavelengths of 635 nm, 532 nm, and 467 nm, respectively (Figure 1). This configuration encompasses over 99.9% of the real surface color database (Pointer colors).


Frame rate

We conducted a study of flicker, which is the primary factor in deciding the frame rate for SHV video.

Figure 1. Chromaticity coordinates for the three primary colors in the colorimetry system chosen for SHV (Table) and comparison with existing systems (Pointer colors shown in color)


We determined the critical fusion frequency (CFF) for perception of flicker using the viewing angle and the illumination duty ratio of the display as parameters and adjusting the frequency. Figure 2a shows the relationship between duty ratio and CFF. As the duty ratio increases from 30% to 90%, the CFF drops from 80 Hz to 65 Hz. This shows that for hold-type displays, there is a trade-off between flicker and motion blur. Figure 2b shows the relationship between field of view angle and CFF. CFF increases as the FOV angle increases, , and this is consistent with the perceptual characteristic that sensitivity to flicker is higher in peripheral vision than in central vision. For a FOV of 30 degrees, suited to the design viewing distances of Hi-Vision, CFF exceeds the field rate slightly about 65 Hz, but at 100 degrees which is the intended FOV for SHV, it exceeds 80 Hz. This result suggests that the field rate for SHV will need to be set higher than the current 60 Hz.

Figure 2a. Relation between display duty cycle and CFF Figure 2b. Relation between display field-of-view angle and CFF

We also continued to our standardization efforts on SHV (UHDTV) at ARIB, ITU-R and SMPTE. We want to promote awareness of SHV as a next-generation broadcast standard and have proposed the colorimetry system described above to ITU-R after deliberations at ARIB. At SMPTE, we revised the UHDTV video standard (SMPTE 2036-1), by adding frame rates of 24, 24/1.001, 25, 30, and 30/1.001 fps.






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