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EXTRACTS DESIRED CONTENT FROM VIDEO DATABASES
At the present time, it's difficult and time consuming to
search through video databases for specific content because
video graphics involve much more data than still pictures.
However, a prototype search engine developed by engineers at
Mitsubishi Electric Corp. in Japan is expected to make the
task much easier.
The engineers used advanced MPEG7 video compression
technology to develop a search engine that enables data to be
handled like graphic elements. Users can search for specific
scenes by inputting a rough sketch of what they are looking
for. The system then uses the input to search for scenes with
similar images in a MPEG7 database on magnetic disk.
The experimental search engine has been able to locate a
desired scene almost instantly, although its success to date
is due partly to the fact that the system currently contains
only limited data. The engineers plan to add more data through
which to search, plus a function that narrows down conditions
for the search and enhances the system's accuracy.
For information: Mitsubishi Electric Corp., Mitsubishi
Denki Bldg., 2-3 Marunouchi, 2-chome, Chiyoda-ku, Tokyo 100,
Japan, telephone: 011-81-3-3218-2111.
BROADBAND, INFRARED COMMUNICATION SYSTEM
A new link design is the key to a reliable, broadband,
wireless, local area network (LAN) built by engineers at Penn
State's Center for Information and Communications Technology
Line-of-sight or point-to-point infrared signal
transmissions, which are used in TV remote controls, are very
efficient at low power levels but require alignment between
the transmitter and the receiver. If blocked, the signals
cannot get through.
Non-line-of-sight transmission systems use a broad diffuse
beam and don't require alignment for transmissions, but they
suffer from low power efficiency and low broadband and error
Penn State's new link design incorporates a multi-beam
transmitter with a narrow field-of-view receiver. To form an
indoor LAN for a group of computers, each computer is equipped
with a low power infrared source and a holographic beam
splitter. The low power beam is separated into several narrow
beams, which strike the ceiling and walls and form an
invisible grid throughout the room. These beams are reflected
at each of the strike points and used to send or receive
information. The narrow field-of-view receivers filter out
noise and provide continued coverage, even if some of the
transmitter beams are blocked.
The system has a bit-error rate of only one error per
billion bits in 99 percent of the coverage area at bit rates
up to a few hundred megabits per second and uses transmitted
power levels below one watt.
For information: Mohsen Kavehrad, Penn State, 0229
Electrical Engineering East, University Park, PA 16802,
telephone: (814) 865-7179.