contents.m

基于声源的方向定位程序

Time Delay Localization
-----------------------

This directory has files for doing time-delay localization.  In
time-delay localization, a source emits a sound (or some other type of
signal), which is received at a number of microphones (or other sensors).  

The sound arrives at the microphones at slightly different times.  For
any two microphones, the delay between the arrival times at the
microphones determines a curve -- a hyperbola -- on which the sound
source must lie.  With three or more microphones, the intersecting
hyperbolas determine the sound source location.

Since there is error in the measurement of the time delays, there will
be error in the measured location.  Multiple time-delay measurements
allow the position of the sound source to be pinpointed with higher
accuracy.

To make this localization method work, you need to know

  - the locations of the microphones (the array),
  - the speed of sound (assumed to be uniform over the whole area), and
  - either (1) the time delays between pairs of microphones, or (2) the
    arrival times of the sound signal at the different microphones
    (from which the time delays are computed)
    

The M-files of interest are

enterDelays.m	lets you enter the time delays between microphones
fileDelays.m	reads the time delays from a file instead of from the keyboard
locateDelays.m	given the time delays, computes and plots best-fitting location

enterTimes.m	lets you enter the times the signal arrived at each microphone
fileTimes.m	reads arrival times from a file instead of from the keyboard
locateTimes.m	given arrival times, computes and plots best-fitting location

test.m		example run of the code (uses testarray4 and testpos12)
locAccuracy.m	plots the relative accuracy of locations for a given array


Auxiliary functions are

timesToDelays.m		auxiliary function for enterTimes; calculates delays
checkScale.m		controls entering times in seconds or milliseconds
bestFit.m		actually computes the best-fit location
CalcDeltaTimes.m	auxiliary fn to bestFit; calculates arrival times
CalcDeltaJacobian.m	axuiliary fn to bestFit; computes guess-location error
dist.m			Euclidean distance function
showResults.m		plots microphones, hyperbolae, and best-fit location
plotPhones.m		auxiliary function to showResults; plots
PlotHyperbola.m		plots a hyperbola
PlotHyperbolas.m	plots several hyperbolae
Spiesberger.m		closed-form solution for 3-phone case