Sound Source Localization

Sound Source LocalizationUnder the supervision of Josef Strm BartunekBy Srikanth Varanasi(931015-3318)Addula SriKrishna Reddy(931218-4832)1 out of 15Sound Source LocalizationProcess of determining the location of the sourceHuman Hearing mechanism has a capability to locate a sound precisely.This works even with a single ear.To implement this artificially we require an array of microphonesThis process can be accomplished in a number of ways.One of them is to find the location of sound source based on Time Difference on Arrival(TDOA).2 out of 15Localization ProblemLocation of the source of sound - not knownEstimate the location of the source based on the time delays estimated. 3 out of 15(0,0)(0,d)(0,2d)(0,3d)X-AxisY-AxisSound SourceReference micat (x,y)Sound Source Localization Environment that considered Difference in distance between ref mic and mic 3 w.r.t. sourceAlgorithms ImplementedSteepest Descent AlgorithmWn+1 = Wn - (n)here (n) = E{|e(n)|2}, e(n) is the error function.Least Mean Squares AlgorithmWn+1 = Wn - (e(n) x*(n))4 out of 15ResultsAssumed a system with one source and 7 mics including ref. mic for sound source localization.Assumed source location at (10,7).Assumed distance between mics is d = 3 metres.Theoretically calculated delays between reference mic and ith mic are [-0.0067;-0.0120;-0.0149;-0.0143;-0.0105;-0.0045].Delays estimated from the phase of impulse response of the system are [-0.0068;-0.0121;-0.0149;-0.0144;-0.0105;-0.0046].The Estimated Location of source is (10.0022, 6.9364).5 out of 15Results

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Flow Chart10 out of 1511 out of 15Flow ChartObservationsThe Steepest Descent algorithm using Squared Error Function in terms of samples converges faster than the one using Squared Error Function in terms of distance.For Higher sampling frequencies the Steepest Descent algorithm using Squared Error Function in terms of samples doesn't converge.12 out of 15ConclusionsThe estimated delays in both time and samples are accurate and compare well to the theoretical values.The impulse responses estimated using LMS are similar to the filters used for delaying the reference signal.The unwrapped phase plots of the impulse responses are approximately linear.The estimated location of sound source is accurate and within the contour of the squared error function. 13 out of 1513Scope For Furture Work14 out of 15This approach can be converted in to a 3D model for estimating the location of a sound source.This approach can be extended for localizing a moving source in real time applications.ReferencesMonson H. Hayes, Statistical Signal Processing And Modelling, John Wiley & Sons, April 11th 1996.15 out of 15