From: rick@cs.arizona.edu (Rick Schlichting)
Newsgroups: comp.research.japan
Subject: Kahaner Report: Visit to NHK Sci & Technical Research Lab, Aug 1992
Date: 26 Aug 92 21:46:00 GMT


  [Dr. David Kahaner is a numerical analyst on sabbatical to the 
   Office of Naval Research-Asia (ONR Asia) in Tokyo from NIST.  The 
   following is the professional opinion of David Kahaner and in no 
   way has the blessing of the US Government or any agency of it.  All 
   information is dated and of limited life time.  This disclaimer should 
   be noted on ANY attribution.]

  [Copies of previous reports written by Kahaner can be obtained using
   anonymous FTP from host cs.arizona.edu, directory japan/kahaner.reports.]

To: Distribution
From: 
 David K. Kahaner
 US Office of Naval Research Asia
 (From outside US):  23-17, 7-chome, Roppongi, Minato-ku, Tokyo 106 Japan
 (From within  US):  Unit 45002, APO AP 96337-0007
  Tel: +81 3 3401-8924, Fax: +81 3 3403-9670
  Email: kahaner@cs.titech.ac.jp
Re: Visit to NHK Science & Technical Research Lab, Aug 1992
24 August 1992
This file is named "nhk.92"

ABSTRACT. Visit to NHK Science & Technical Research Lab, Aug 1992


In an earlier report, ["3d-2-92.1", 21 Feb 1992], I explained the
general themes of NHK's (Japan Broadcasting Corporation) research
directions, and also described a few of the specific research projects
that I saw during a visit in early 1992. Recently I was able to re-visit
the NHK Science and Technical Research Labs to have a look at some other
projects. (The visit was in the company of Dr.S.Yamamoto, the ONR Asia
Office Director, and he has collaborated with me in the current report.)

Without trying to repeat the overview material given earlier, we note
that NHK is the Japanese public broadcasting organization. The S&T
Research Labs are the NHK's main research arm. It was established in
1930 and currently has 330 staff (270 scientists) and an annual budget
of 7Billion Yen (a little more than $50Million US).  This represents
slightly more than 2% of NHK's total employees and about 1.5% of its
total budget.  (Laboratory sizes have to be judged by Japanese
standards--this is considered a large laboratory here, perhaps
comparable to an organization of twice its size in the West.) The
research themes of the Labs cover a wide range of broadcast technology
from basic research in audio-visual science, materials and solid-state
physics to the development of broadcast equipment and systems.
Activities are in three major research goals, "new broadcast services",
"improving existing broadcast services", and "basic technology to
support future broadcasting". A large part of NHK's activities are
related to direct satellite broadcasting (DSB) and Hi-Vision (HDTV of
Japan). DSB began 24 hour service in June 1989 on two channels.  
Currently there are eight hours per day of Hi-Vision DSB programming.  
DSB means that individual users can purchase a small antenna dish--
approximately 15 inches in diameter for as little as $150US, and receive 
satellite programming on their home TVs.  The Japanese BS-3b satellite 
has a traveling wave tube (TWT) permitting about 120watts of power 
output, permitting these small diameter antennas.  Such dishes are 
extremely numerous in Japan; they are commonly attached to balcony 
railings and window ledges as well as on rooftops.  Related to this there 
is a great deal of antenna research at NHK, for example shaped onboard 
antennas, as well as flat-panel and auto-tracking antennas for receivers.  

A very large amount of Hi-Vision TV is being made available (in Japan) 
from the Barcelona Olympics. Special Hi-Vision cameras feed to
compatible VTRs which, after coding, feed via satellite and ground link
to Japan.  Signals are eventually routed to one of the broadcast
satellites (BS-3b) from which signals can be received by the small home
dishes (BS-antennas) mentioned above. A special BS tuner is required
(available on many home TVs here in Japan and not expensive), and also a
Hi-Vision decoder (MUSE), which is expensive.  After decoding the
signals can be displayed on a Hi-Vision TV.  A 36 inch diameter
Hi-Vision monitor costs about $20,000US; the decoder is about another
$10,000US. Panasonic, Hitachi, Toshiba, Sharp, Sony, NEC, JVC, Pioneer,
Mitsubishi, Sanyo, and other vendors have such products. The price is
still far too high for ordinary users but a substantial number of
systems are in commercial use for demonstrating products, in museums,
etc. Prices are expected to drop rapidly and the large volume of
programming will certainly pique home viewers interest.  Personally, I
can attest to the extraordinary impact of the Olympic events, when
viewed on a large screen in this high definition format.

Direct Broadcast Satellites are widely accessed here, even for non-HDTV.  
NHK is looking for new services making use of DSB. One such could be 
broadcasting high definition still pictures and sound, for potential use 
in pictorial and photographic art programs and detailed information 
programs for catalogs, etc. Various standards groups are working toward a 
standardized high efficiency picture coding scheme for such still 
pictures. The current approach to picture coding is by use of the 
discrete cosine transform (DCT). By adjusting the coding parameters both 
good picture quality as well audio can be transmitted through the data 
channel of existing satellite TV broadcasts.  An uncompressed high 
definition still picture is about 4Mbytes. Based on the capacity of the
data channel of a broadcast satellite, it would take about 90 seconds to
transmit the original picture and some stereo sound, but by using the
DCT and alittle picture quality degradation, this can be reduced to 1-5
seconds (depending on the image).  Since both still video and audio can
be put onto a DAT (digital audio tape) this is seen as a nice "package"
service.  This is an interesting application making use of what is
currently unused capacity in existing satellites.

The Japanese Hi-Vision system is an analog system, whereas plans in the
US are for an all digital HDTV system. The latter is claimed to be much
more flexible and is thought to represent more advanced technology.
Neither Yamamoto nor I are experts in any significant aspects of TV
broadcasting, but we were curious about this state of affairs and asked
our NHK hosts for their views. 

     Masaki Hayashi
     Video Engineering and Data Processing Research Division
     NHK S&T Research Labs
     1-10-11 Kinuta, Setagaya-ku
     Tokyo 157 Japan
      Tel: +81 3-5494-2311; Fax: +81 3-5494-2309
and
     Tetsuo Mitsuhashi
     Senior Research Scientist
     Visual Science Research Division
       (same address)
      Tel: +81 3-5494-2362; Fax: +81 3-5494-2371
      Email: MITSUHASH@STRL.NHK.OR.JP

Their opinion was that yes, digital high definition TV was the clear
future direction, and there was plenty of work in progress at NHK along
those lines. But many technical problems remained to be solved,
including a very serious one of digitally reducing the amount of data 
that was generated at the source, and they are not expecting a 
significant infiltration of digital receivers until next century (10-15 
years was the estimate from our hosts, before analog HDTV is replaced by 
a digital system). In the meantime they feel that while there are many 
technical issues that are unique to digital TV, there are others that 
overlap with analog technology, and the Japanese are working to address 
these right now.  Furthermore, problems of infrastructure, programming, 
culture, etc., will not be so different between the two technologies and 
and experience gained now will be useful for the future too. In other 
words these scientists did not seem concerned about being "jumped" by 
Western technology as they follow their own course.  

During this visit we had the opportunity to see four specific research
projects. These are described below.

SUPER-HARP (ULTRA-HIGH SENSITIVE CAMERA TUBE)

In 1987 NHK and Hitachi announced that an experimental camera tube had
exhibited high sensitivity with a quantum efficiency greater than one,
because of a multiplicative effect resulting from a high target electric
field of 240Volts. This was about 10 times as sensitive as conventional
camera tubes and gave a burst of life to research in camera tubes, which
many believed would soon be replaced by solid state imaging devices such
as CCDs. Very recently NHK and Hitachi have improved the sensitivity by
another factor of ten, resulting in what they have called the Super-HARP
tube (High-gain Avalanche Rushing amophormous Photoconductor). The 18mm
tube has a target size of 6 mu-meter (three times that of the original
HARP), necessitating a corresponding increase in the imposed electric
field (to about 640V) to maintain an electric field of the order of 10^8
V/meter required to produce the multiplicative effect.

In addition to increasing sensitivity the delay lag has also been
reduced by about two thirds. This is the time lag in the field after
incident light has been turned off; viewers observe this as streaks that
remain on the TV image when a bright light source is moving. NHK
scientists believe that the lag can be decreased even further. 

The current Super-HARP tube has a resolution of more than 800 TV lines
and is limited by the size of the electron beam. In other words if
electron optics for HDTV were used, resolution could be increased
further. 

We were shown a live demonstration of this new camera in a side by side
comparison with a traditional SATICON color camera both viewing the same
indoor scene. In the latter case, the TV image was almost totally black
while the new camera image was clear, sharp and brilliantly colored.

In addition, we saw a video made with the new camera of various
astronomical events such as nebula and aurora. Applications to
underwater and other dark scenes were also mentioned and are obvious.
In a related application we also were shown a beautiful video taken by a
HDTV (ordinary) HARP camera from the top of Moana Loa during the recent
solar eclipse. Striking details of solar prominence were clearly
visible.


AUTOSTEREOSCOPIC 3D TELEVISION DISPLAY

In the report referenced earlier we also briefly discussed this device.
NHK scientists, along with most other researchers in this field within
Japan, believe that any future 3D TV display must be a "glassless"
system in order to be accepted by home viewers. Several projects are
inexorably moving forward in this direction. Lenticular screens are well
known from 3D "post cards". These screens consist of an array of half
cylindrical lenses. In the TV application, stripe images from 3D TV
cameras are displayed behind the screen to match the screen's pitch and
3D images are then visible from different viewing points. There are a
great many complex aspects to this approach. NHK has been working on
flat-panel display devices because of their ease of optical alignment
and a 12inch PDP (plasma display panel) has been developed for viewing
images from four cameras. In addition a 9inch EL (electroluminescent)
display with input from five cameras has been built. A large, 40inch LCD
projection TV display has also been built for viewing images from two
cameras.

Finally, there is a 50inch rear projection TV display. This is a joint
project of NHK, Sanyo, and Toppan Printing, with Toppan building a new
"hollow" lenticular screen combining sections of glass and air. NHK
claims that the combination of different refractive indices shorten the
focal length for incident light, resulting in increased light
transmission and reduced screen thickness leading to a weight reduction
of about two thirds. When I saw this system in January 1992, four
cameras were used to supply images. Thus viewers effectively had four
views, which put together, generated an interesting but not spectacular
image. Since then, the number of cameras have been doubled to eight. The
camera lenses are essentially touching so there is not much room for
further improvement here without major optical changes. The resulting
image is also much improved in its 3D quality, while remaining bright
and highly viewable. Seating position is still constrained both as to
distance from the screen and lateral movement but the additional cameras
made the image more interesting to me and reduced the need to shift my
head as much as before. The 50inch screen has an HDTV aspect ratio
(16:9) and the LCD panel has 1440x1024 pixels with three colors. It is
adequately bright to watch under normal room lighting.

LIGHTWEIGHT NEARLY-HDTV CAMERA

HDTV cameras are very expensive. In addition, their size, weight, and
battery drain make them less convenient to use than conventional TV
cameras. One interesting experiment that NHK scientists are engaged in
is to see what compromises can be accepted in visual quality that lead
to significant reductions in size and cost. The most interesting of
these is a 2/3inch (detector) camera with 3.9million pixels total within
the detector, but not evenly divided among the three primary colors.
Instead 2.6million pixels are used to detect green, the remainder for
the other colors.  (This choice was based on experiments with human
visual sensitivity.) The resulting camera is almost the same size as a
standard professional TV camera, and much smaller than a conventional
HDTV camera.  We were shown live indoor pictures from the new camera,
and these were (to us) as good as HDTV images, and clearly superior to
standard images. NHK claims that much smaller batteries can be used, and
that the light weight and small size translate directly into cost
savings. They expect that these cameras can be priced at half of a
conventional HDTV camera. They also explained that these cameras are in
use at the Olympics in Barcelona for their first significant field test.

DESKTOP PROGRAM PRODUCTION

This is a clever synthesis of multimedia technologies to produce an 
integrated working environment for TV program production. Maintained on 
some databases are computer graphics images of various "sets" as well as
components such as tables, bookcases, etc. On separate video disks are
moving images of "actors". In the case of the current system the latter
are real video, although they could easily be animated. The user of such
a system can create a virtual studio set using real-time computer
graphics to access, process, synthesize, and edit all the audio and
video. On an attached workstation, not only the time-coded VTR tapes but
also other attributes such as virtual camera position, object shape,
lighting, etc., can be managed. A usual TV editing system can manipulate
audio and video, NHK's can make changes in these other attributes as
well.  The current system was shown to us with two 2D actors, and one 3D
actor. The most interesting aspect of this work was that it operates in
real time.  To do this, NHK has built a video-rate processing system for
NTSC signals (called Picot) composed of several processors connected in
parallel to allow fast image generation, motion adaptive correction,
geometrical transformations, video synthesis, etc., by software.
Unfortunately all the hardware was disassembled during our visit and we
were only shown a video of a typical editing session. But NHK is
currently developing a higher speed processor for Hi-Vision signals. The
software is written in C on a standard multi-media workstation. The
project involved nine scientists over three months for the software
aspects, and work over more than five years for the hardware
development.

A related activity, which we did not see but were told about is called 
Synthevision. This processes background stills and motion pictures 
digitally, and allows them to be synchronized to the panning, tilting,
zooming, and focusing of a live camera. Backgrounds can be generated by
computer graphics to eliminate studio sets. NHK notes that as
backgrounds can be changed electronically, the operational costs of
studios can be reduced. There is also experimentation of "pseudo" 3D by
using multi-layered images at different depths and synchronized to a
camera dolly's movement.

I would like to thank Mr. Hayashi and Mr. Tetsuhashi as well as numerous 
othe NHK scientists for their assistance during our visit and also in the 
drafting of this report.

----------------------------END OF REPORT------------------------------