Re: Sound recognition (not voice) - recording instances and duration of

[Marc_F_Hult <MFHult@xxxxxxxxxxxxxxxxxxxxx>]

On 13 Jul 2006 04:05:29 -0700, "BondyBoy" <bondyboy@xxxxxxxxx> wrote in
message  <1152788729.378017.309970@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>:

>I am trying to automate the recording of when, and how long for a
>certain audio "Alarm" goes off. This alarm is located about 30 feet
>from our house and the alarm can be going off for anywhere from 2 mins
>to 30+ mins.
>
>I need to use my PC (which is on 24-7) and its microphone (which i can
>point towards the source of the sound) to take a note of when and for
>how long the alarm sound is operating. I was thinking of using some
>speech recognition program for this but am unsure if this would work
>for the "Wa Wa Wa" of an alarm and not speech as is intended in these
>applications.
>
>I'm a VB programmer by trade so probably would be able to build
>something to do this if I just knew where to begin. . .
>
>it would be sort of like a motion dector security system but being
>triggered by a specific sound instead of motion on a camera (the sound
>in question is on a very short repeating loop)
>
>does anyone have some usefull pointers on how something like this could
>be achieved?

The ca. 1999 Savoy Cyberhouse home automation software that I use has a
function module called "Listen" that can be trained to detect and respond
via rule sets to arbitrary environmental sounds such as alarm, clothes
dryer, furnace blower, etc for which it is trained. Alas, the software was
years ahead of its time and is no longer available.

There are many other efforts past and ongoing for both arbitrary sounds
and specifically alarm sounds using a variety of techniques.

"Incorporating Contextual Audio for an Actively
Anxious Smart Home" Simon Moncrieft et al
http://www.computing.edu.au/~svetha/papers/papers2005/conferences/moncrieff_ISSNIP_2005_373-378.pdf

The term "active anxiously" captures much.

"Detecting Alarm Sounds" D.P. Ellis
http://www.ee.columbia.edu/crac/papers/ellis.pdf

This is what you are trying to do, but please read what I write below on
the importance of a high-quality signal (close by, directional
microphone).

Here's SOLAR (Sound Object Localization and Retrieval in Complex Audio
Environments) the purpose of which is to " to detect and identify sound
objects, such as car horns or dog barks, in audio " that includes C source
code and some instructions.

http://www.cs.cmu.edu/~dhoiem/projects/solar/

source code;
http://www.cs.cmu.edu/~dhoiem/projects/solar/solar_src.zip

I used to use something called "Audio Signal v 1.1"

In general, needed steps are:

A#1) Signal acquisition. Both for monitoring and obtaining an initial
example so that you can "train" the software. A highly directional and
very close by microphone is key to success in your "from the wild"
scenario.  This in itself might be the major challenge. I can't emphasize
this enough. Most folks greatly underestimate the importance of microphone
placement. Whatever you were planning to do can probably be improved -- do
so!

2) Signal conditioning. If it is an alarm, it will have one or two
frequencies that predominate. It might help to set up two parametric
equalizers with a narrow ("notch') bandpass (one per stereo channel?) to
reject everything except the frequency/ies of interest. An alarm warble
tone may have two principal frequencies. You may want to remix to mono or
leave separate so as to be able to logically AND the recognition. But
sometimes the characteristic signal will be in the overtones and
distortion (or a combination of the fundamentals and overtones), so this
may be counterproductive. Depends in large part on how much background and
extraneous noise there is  (See A#1 above).

3)Training. You will want an example of he sound captured with the same
equipment a you plan to use for monitoring with which to train the
software.

5) Recording. Easily done these days directly to a digital file.

6) Detection. This is where the software is used. As previously remarked
by others, this can be assisted by manual review/inspection of the sound
file.

Good luck!  (And let us know what you work out.)

... Marc
Marc_F_Hult
www.ECOntrol.org