"Super Hi-Vision" Shows Progress in Recent Lab Tests

There’s high-definition television as we know it, and then there’s super, or “ultra” HD imaging that few of us have experienced. Japanese broadcast/research organization NHK’s groundbreaking new 33-million pixel imager fits in the latter category.
New prototype imager Conventional imager
Optical format 2.5 inch 1.25 inch
Light receptor surface size 29.8mm horizontally, 16.4mm vertically 16.6mm horizontally, 9.2mm vertically
Effective # of pixels – horizontal 7680 3840
Effective # of pixels – vertical 4320 2160
Pixel size 3.8 µm square 4.2 µm square
Signal output Differential (LVDS) Single-end (LVCMOS)
Signal output number 12-bit 16ch-parallel 10-bit 16ch-parallel
Scanning scheme Progressive scanning Progressive scanning
Specification comparison between new prototype imager and conventional imager (8M-pixel). Source: NHK
NHK is one of the pioneers of today’s HDTV technology (as it has been since its days working with the original Hi-Vision analog HD format). Now, its research engineers have developed a CMOS sensor capable of delivering 8K by 4K video resolution (7680 x 4320 pixels) for what’s called “Super Hi-Vision” (SHV).

At a recent public demonstration in NHK’s lab, the new history-making 2.5-inch sensor was shown. NHK has shown SHV images before-but those were made with a camera jointly developed with Micron Technology using a four-imager pickup system with a diagonal offset pitch of half a pixel. However, a single, SHV sensor has been the holy grail of researchers.

NHK worked with a U.S. joint venture company to develop the new image sensor and fabricate a prototype. During the recent demo, the engineers used the sensor to capture monochrome moving images with a 12-bit gray scale and progressive scanning. The size of the pixel was designed as large as possible for requirements such as sensitivity and dynamic range.

The broadcaster has used Super Hi-Vision cameras that employ four 8-megapixel CMOS sensors, jointly developed with Micron Technology Inc., to produce 8k x 4k video. The next-generation 3.8-by-3.8-micron pixel in the latest version is almost the same size as the ones used in the eight-megapixel image sensor.

NHK said its future work on the project includes enhancing the resolution of the imaging and display system and improving tonal reproduction. Also planned is a color camera using multiple SHV image sensors.

The project is part of a next-generation HDTV system that’s targeted for sale in 2009. To accompany the SHV video system, NHK is also working on a 22.2 channel surround sound system.