Sound Localization Matlab, Please Help!

On 17 Feb, 22:15, Glen Herrmannsfeldt <g...@ugcs.caltech.edu> wrote:
> Tim Wescott wrote:
>
> (snip)
>
> > I can think of
> > four likely possibilities of what may happen: one, he or she is waiting
> > for your questions, ready to give you guidance (not answers, mind --
> > guidance); two, he or she is severely overworked, and can't help (in
> > which case you picked the wrong school, and we'll try to help); three, he
> > or she isn't interested in doing his/her job and _won't_ help (in which
> > case you or your school picked the wrong prof, and you may be able to
> > switch); finally, you're being too needy, and your prof is trying to push
> > you out of your comfort zone so you'll succeed in the real world (this
> > can be hard to tell from three from inside your own head -- ask your
> > friends, and review my comment about the word "thesis").
>
> There is also five:
>
> Prof doesn't know, but would find the answer useful in his research.
> (I will guess that women wouldn't try this.) &#4294967295;When they get the answer,
> it will end up in a published paper with his name on it.
>
> I have heard that this happens much more often that it should.

I suppose that's how the world works these days: Professor runs
deparmtent (presumably) overseeing work; PhD student runs day-to-day
tutoring and supervising of students; students to hands-on work.
The prof needs his name on the paper to reap the financial rewards
when inventories are counted at end-of-year. The others want their
names on the paper because they did the work.

Where I used to work, all three persons got their name on the
paper as co-authors. No one had any problems with that. The
problems occur when somebody are left out.

Rune

Thank you for all your responses. In fact, the situation is that my
supervisor is the head of my department, and has no time to meet me, and as
such, I am lost! Your responses have allowed me to revise my original post,
and I have realised that the problem wasn't that clear. I have only two
microphones, and yes, I am in control of the sound. What I am trying to
implement is a sound intensity probe.

Since my original post, I have made some advances. I have done some
recordings in a field, so no errors occur. The microphones are held in a
constant position whilst recording. In each recording, the angle of arrival
of the sound is different (i.e. I have moved the sound source to a
different location on a circle of the same radius.) When I analyse the
data, I've plotted a graph of the phase versus the frequency. The resulting
graph is somewhat of a cut-saw image, such as:

/|/|/|

Excuse the crudeness of this diagram, it was the best I could do from the
characters on the keyboard! The slope of this graph should give me some
information about the sound location, and I should be able to
experimentally determine the angle of arrival, and the distance from the
two mics.

I have used the fuction tfestimate in MATLAB, and the angle of the Tf for
the phase. I am somewhat confused as to how to work out the distance and
angle, could someone please clear it up!

staplep wrote:
> Thank you for all your responses. In fact, the situation is that my
> supervisor is the head of my department, and has no time to meet me, and as
> such, I am lost! Your responses have allowed me to revise my original post,
> and I have realised that the problem wasn't that clear. I have only two
> microphones, and yes, I am in control of the sound. What I am trying to
> implement is a sound intensity probe.
> 
> Since my original post, I have made some advances. I have done some
> recordings in a field, so no errors occur. The microphones are held in a
> constant position whilst recording. In each recording, the angle of arrival
> of the sound is different (i.e. I have moved the sound source to a
> different location on a circle of the same radius.) When I analyse the
> data, I've plotted a graph of the phase versus the frequency. The resulting
> graph is somewhat of a cut-saw image, such as:
> 
> /|/|/|
> 
> Excuse the crudeness of this diagram, it was the best I could do from the
> characters on the keyboard! The slope of this graph should give me some
> information about the sound location, and I should be able to
> experimentally determine the angle of arrival, and the distance from the
> two mics.
> 
> I have used the fuction tfestimate in MATLAB, and the angle of the Tf for
> the phase. I am somewhat confused as to how to work out the distance and
> angle, could someone please clear it up!

The phase illustration is typical of wraparound, the calculated phase 
being confines to "principal value", while the real phase can accumulate 
forever.

Jerry
-- 
Engineering is the art of making what you want from things you can get.
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