8K: Plenty of Pixels For Everybody!November 2nd, 2009
By Peter Putman of Roam Consulting.
During the SMPTE Fall Tech Expo last week in Hollywood, I chaired a session on trends in display technologies. One of the four papers in my session discussed the ongoing efforts by NHK to develop an 8K camera-to-screen system, in conjunction with Canon, Astro, and Fuji, while another paper detailed a companion 8K LCoS projection system, developed by JVC.
The 8K camera system, which was shown at NAB back in April, is of interest because it uses a mastering and acquisition design philosophy, i.e. all video production in the future would rely on 8K cameras and reference displays, with downconversion to 4K and 2K an integral part of the system.
NHK’s Ultra-High Definition TV (UHDTV) employs red, blue, and dual green-channel sensors, with the G1 and G2 sensors offset from each other to pick up additional detail. The camera delivers images with 33 megapixels of resolution and can transport a 22.2 surround sound mix. That’s a tremendous data payload, and it requires 16 HD-SDI connections over optical fiber just to move the 7680×4320 frames (59.94p frame rate) from point to point.
The NHK format converter, developed by Astro, delivers real-time downconversion to 3840×2160 and 1920×1080 formats in three ways. The first is a straightforward downconvert to 4K or 2K from each master 8K video frame. The second process divides the image into quadrants and delivers any quadrant as "cut-out" 4K content, while the third process extracts any of 16 screen areas for 2K imaging, also as "cut outs."
4K and 2K format downconversions aren’t just limited to specific image sections. The Astro format converter can also pan across any part of the screen and extract 4K and 2K sections as needed, including zooming and cropping any part of the full frame 8K images.
The pan/tilt/zoom functions are also lined to a robotic camera control system, as shown in a demo tape of a soccer match. While the main 8K scenes were being captured, a smaller 2K "tile" moved about the screen, grabbing and extracting real-time footage of activity around the goal and at midfield.
Canon’s custom zoom lens developed for this camera has a zoom ratio of 10x and can resolve 250 line pairs per millimeter, with a minimum focal distance of 2 meters, or 50 millimeter in macro mode. A companion wide-angle lens also offers the same resolving power and has a 100-degree field of view, with minimum focal distance of 0.4 meters.
JVC’s companion 8K D-ILA projector uses three brand new 1.7" VA LCoS panels, each with a pixel pitch of just 4.8 µm and resolution of 8192 x 3420 pixels. Switching transistors have gotten smaller, undergoing a 30% reduction in size. JVC has also come up with a smaller capacitor design to fit in the boundary between the reflective electrode and each transistor, and the gap between pixels has been reduced to 0.24 µm. All of these developments have increased the aperture ratio to 93% while boosting peak (sequential) contrast to 20,000:1.
A new optical engine was designed for the 8K system, employing a 3 kW xenon lamp and wire grid dichroic filters, similar to those employed in JVC’s home theater projectors. According to JVC, this has resulted in a luminous efficiency of 3.3 lumens/watt, with ANSI contrast specified at 400:1 and ANSI brightness specified at 10,000 lumens.
All-new optics are also part of the package, with a 40mm prime lens providing a projection throw ratio of 1:1 to screens ranging in size from 8.3 feet to 42 feet. The data transfer rate of 72 GB/s required a custom fiber optic interface using 16 HD-SDI channels, with 12 bits per pixel sampling and a 60p frame rate. The transport format conforms to SMPTE-2036 and allows for a scalable, layered 8K/4K/2K structure.
Although JVC and NHK didn’t touch on 3D during their papers, this 8K platform should easily be extensible to 3D acquisition and display. The D-ILA panels have an LC twist time of 4.5 ms, and interlaced or segmented left eye/right eye sequencing could easily be employed for 4K effective resolution, using the standard 60p frame rate. (No word on support for faster frame rates, such as 120 Hz for full 8K 3D - but that’s wishful thinking for now!)
Neither the camera system nor the projector has been commercialized just yet - they’re still in the prototype stage. But the images they produce are mind-blowing and a fascinating glimpse into the future of video beyond HDTV…a time that’s much closer than you think.