How can I use MATLAB to perform a least squares estimation?

[oregonianish]

Specifically, I am working with six digitized audio signals input via an array of microphones in order to find the location of a speaker within a room based upon time delay of arrival. I have been pointed in the direction of using a cross-correlation function in order to determine phase differences between the signals arriving at each microphone. From there, I must determine the distance from each microphone to the audio source in order to pinpoint the source's coordinates, or at least an angle to which a camera must point to capture video of the source. Any help would be greatly appreciated.

Danny

 

[joe3]

Hi,
Use xcorr (Signal processing toolbox). Read the help (or doc).

Joe
The new BSTeX- Equation viewer for Matlab7

http://www.geocities.com/bstex2001

 

[MikeyP]

I'm not sure how the thread title relates to your post, but you can simply use the matlab backslash operator "\" to perform least squares operations.

M

--
Dr Michael F Platten

 

[GregLocock]

He's probably going to get a least squares estimate of the source location.

Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[oregonianish]

That's right. I would like to use least squares estimation to determine the approximate source location. Please excuse my vague post.

Danny

 

[oregonianish]

From the time delays I obtain using the "xcorr" fucntion I will find range differences for each pair of microphones. A range difference is found by multiplying the time delay by the speed of sound. The range difference represents the difference between the distance from the source to the first microphone of a pair and the distance from the source to the second microphone of the same pair. With the fifteen range differences, based upon fifteen possible pairs for six microphones, and the predefined locations of each of the microphones, I would like an algorithm to perform a least squares estimation of the location of the sound source.

I do not know how to proceed from the point of having obtained the range differences. Any help with the implementation of a least squares estimation would be greatly appreciated.