The Self-Deconvolution Data
Restoration
Algorithm, or SeDDaRA, was developed to
quickly
and effectively remove degradations such as focus and motion from
digital images. However, there is no reason to suspect that this
technology cannot
be applied to one-dimensional signals as well. In fact, our gallery shows several
examples of signal processing.
On this
page, we will demonstrate our progress to apply the technology towards
recorded acoustic waves, or sound, to remove some artifacts of sound
recording and reproduction. These experiments are ongoing, and the
results here do
not represent the full potential of the technique. A research paper is
currently
being drafted and expected to be submitted in June.
The
sound files
on this page are *.wav files and should be read easily by most media
players.
Note:
A research paper has been submitted on the restoration of
audio-frequency
signals using SeDDaRA. See research for
details.
A
frequency response is imposed on any recording of acoustic waves by the
recording medium. In other words, a microphone will alter the way a
sound wave sounds because it is difficult to match the response of a
microphone to that of the human ear. Better microphones, of course,
produce better reproductions. The same can be said for playback.
Speakers do not exactly reproduce the
sound wave as we first perceived it. The SeDDaRA process can be used to
diminish this behavior by correctly the frequency spectrum imposed on
the
wave by the reproduction system.
Here are
two
sound clips that were recorded decades ago on equipment that is not
known to us. The sound was no doubt recorded as an analogue signal, and
someone
in cyberspace had converted them to digital files. We put the clips
through
our process and produced more 'lifelike' representations.
The
following clip is from John F. Kennedy's famous Inaugural speech on
January 20, 1961.
The following clip is much older.
This is from a speech by Theodore Roosevelt on August 12, 1912.
White Noise
In any
acoustic reproduction system, noise created from electronic
amplification can be introduced. We simulated this problem by adding
white noise to sound files,
and then attempted to restore the sound files using SeDDaRA. Now,
SeDDaRA
operates like a selective frequency filter, so noise that has the
frequency
characteristics similar to those in the signal will not be removed.
The
following sound file is a clip from a bassoon quartet. Noise was adding
random number to each point in the data file. The waveform 'Dx-bassoon
quartet' is the restoration. The noise is significantly reduced, but
not totally eliminated.
The next
sound wave is of a synthesized flute playing a scale. As before, noise
was added using a random number generator. The sound file was restored
and is
at the link marked 'Dx-flute'.
We are very encouraged by our recent results! Potentially this
technology
will provide such devices as hearing aids, sound systems, and
telephones
with the ability to not only enhance their reproduction, but also
diminish
the artifacts produced by the instrument that recorded the sound, and
the
surrounding environment. Exciting stuff!
