It’s a Virtual Wonder World with New Generation wireless stereo headphones
Microsoft’s algorithm to make the speaker to work
as a virtual headphone
In field of computers, the word "virtual"
has got more importance. From Virtual Memory to Virtual
PC, the word will remain as a popular word in computer’s
history. Another new word "Virtual Headphone"
is being added shortly. We see in this article, how...
Virtual Headphone is wireless
Today, there are many people who, often, make use
of computer for communication, especially for voice
communication and voice messaging. However, one has
to plug in a microphone separately, or need to have
a headphone plugged in to the computer in order to make
use of the feature. One needs to keep speaker volume
low, in order to get both input and output clearer especially,
in a shared office environment.
Sophisticated audio output
Researchers at Microsoft are working towards making
the audio output more sophisticated. It is learnt that,
a team led by software architect, one Mr. Ivan Tashev,
has recently began a work on an algorithm, which, in
theory, will be able to direct the waves of sound from
the speaker (which is, ideally, a built-in speaker in
computer monitor) into a person’s ears, effectively,
there by paving a way for creation of virtual headphones.
Tashev said that the algorithm could be effectively
used by a wide range of least expensive speakers which
are built into computer monitors.
Achieve a target focused sound
He says that, the primary aim of the algorithm will
be to achieve a target focused sound which makes the
person to hear, what the other one saying, while he
is on a computer aided audio conference call. The information
regarding location will be collected by hardware peripherals
and will be fed into speaker software, which in turn
makes the virtual headphone, to move with the user in
real time. A camera embedded in the computer monitor
will determine person’s exact position. Added
to this, there will be a set of four or five microphones
on or near the computer monitor can be programmed to
localize sound by measuring time differences between
arrival of sound wave at each speaker. Employing a camera
with a microphone can cause improvement in accuracy
and distance at which a person can roam while using
the speakers.
Beam forming technology
The idea is not new now. Military radar systems and
ultra-sound equipments have been made use of the technology
in the past. This technology was called as “beam
forming”. Beam forming is achieved when sound
waves from some speakers, causing micro seconds a delay
says Jiashu Chen, Technincal Manager at Finisar Corporation,
CA. This technology also used in ultrasound equipment,
which is used to take images of fetus in the uterus
and find cancerous tumors. The delayed sound waves combines
in such way that, in some part of space the sound is
cancelled out and in others, sound grows louder. Beam
forming systems are more technically challenging to
build than radar and ultrasound says Chen. As one need
to accommodate a wider range of frequencies, lower frequencies
require different hardware and software considerations
than higher frequencies. Signal processing technology
has improved in such a way that some commercial products
use beam forming. For example, Electronics giants Yamaha,
makes and sells home entertainment speakers, in which
the sound gets bounced off the walls to create virtual
speakers behind the listener’s head. But, the
problem with such speakers is it is too heavily priced.
Calibrate the entire sound system
The reason behind the beam forming becoming expensive
is the large amount of time; it takes to calibrate a
give real world system. Each speaker has got slight
variations in the sound it generates. However, focusing
the sound beam needs extreme precision in timing. The
slight variations in sound can cause large distortions.
Therefore, it is required to calibrate the entire sound
system to the shape of the room in which it is to be
installed.
Software will work with any speakers
It is learnt that, Microsoft wants to develop software
which is good and strong enough to work with any speakers,
which sets different minimum calibration levels for
the users. To make generic speaker to make of focused
sound, Tashev and his group said to have modified the
beam forming algorithm through a higher degree of research
and developmental activities. They designed a part of
signal processing algorithm which is said to be “filter”,
which can accommodate a wide range of manufacturing
tolerances. He further adds that he is trying to find
a happy medium among different tolerances so that the
resultant sound is comparable across the speakers which
require some fine tuning. The researchers are still
trying to find the best ways to implement the speaker
tolerances.
Where to point the beam
According to Tashev, this project is in its early
stages. He adds that, it is not sufficient to have a
good beam former. He says that the project should have
a good sound localizer such as a camera or specialized
microphone array which enables one to determine where
to point the beam. He points that, for the beam forming
algorithm to become successful, it is needed to take
into account, the sound reflections from walls and windows
within the office room or home.
The research work is going on in the field of image
processing techniques which uses cameras to identify
a person’s location for improving the focus of
microphone arrays. “Tracking is really another
hard problem” says Stan Birchfield, professor
at Clemson University. He presently works in the areas
of image processing. He feels that, no one has successfully
found a way to solve tracking problems in a basic environment,
such as an office. He added that, he is quite happy
to see Microsoft is trying to explore the area.
New Windows Media Player
Commercialization of the technology requires a complex
binding of many factors, which could not be possible
even after the research prototype, is made ready. Tashev
says that the reliability of algorithm needs to be tested
yet, with a number of speaker arrays. Microsoft can
work then only, to integrate the algorithm into its
popular Windows Media Player making sure that the drivers
for the same are included in the operating system. Then
only, they need to find companies who are interested
in manufacturing speakers for such applications.
Future will be without headsets
If these happen in planned manner, according to the
planned life cycle, then the result will be great. People
will no longer need headsets for private conversation
or video conference.
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