Experimental Performance Analysis of Sound Source Detection with SRP PHAT- β   Anand Ramamurthy, Harikrishnan Unnikrishn...
Sound Source Detection <ul><li>Objective : </li></ul><ul><ul><li>To detect and locate a sound source within a space of int...
Objective <ul><li>Detection analysis with experimental data to compare the impact of various implementations of whitening ...
Steered Response Power <ul><li>Robust algorithm </li></ul><ul><li>Especially in the presence of multiple interfering sourc...
<ul><li>Signals received at each microphone aligned together by adding appropriate delay. </li></ul><ul><li>Coherent power...
SRCP ∑ Compute  Coherent Power (x,y,z) Uniquely defines (x,y,z)
SRCP … <ul><li>Power estimates get corrupted by noises </li></ul><ul><ul><li>Interfering sources and ambient noise (Uncorr...
PHAT <ul><li>Phase Transform  </li></ul><ul><ul><li>Spectral whitening </li></ul></ul><ul><li>Lower frequencies have highe...
PHAT
SRCP – PHAT  <ul><li>Works well with broad band signals </li></ul>
PHAT -  β <ul><li>Speech is a combination of narrow and wideband signal. </li></ul><ul><li>β   -  Controls the extend of w...
Experimental Setup Speakers (sound source) Office Wall Microphones Field of View
Test  Signals Used <ul><li>Broad band :  400Hz – 5600 Hz colored noise </li></ul><ul><li>Narrowband :  400Hz – 600 Hz colo...
Results
ROC <ul><li>Receiver Operation Characteristics </li></ul><ul><li>True Detection vs False Alarm </li></ul><ul><li>Area unde...
Narrow band Broad band Low reverb. High reverb.
Conclusion <ul><li>PHAT –  β   out performs conventional PHAT in varied operating conditions </li></ul><ul><li>β   ranging...
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My Conferecence Publication

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  • I am Harikrishnan from University of Kentucky. I would like to present the work done by us on Sound Source detection technique, called Steered Response Power using phase transform.
  • My Conferecence Publication

    1. 1. Experimental Performance Analysis of Sound Source Detection with SRP PHAT- β Anand Ramamurthy, Harikrishnan Unnikrishnan, Kevin. D. Donohue Center For Visualization & Virtual Environments Funded in part by NSF EPSCoR Program UNIVERSITY OF KENTUCKY College of Engineering Department of Electrical and Computer Engineering
    2. 2. Sound Source Detection <ul><li>Objective : </li></ul><ul><ul><li>To detect and locate a sound source within a space of interest. </li></ul></ul><ul><li>Approach </li></ul><ul><ul><li>Using spatially distributed microphone array. </li></ul></ul><ul><li>Application </li></ul><ul><ul><li>Speech recognition </li></ul></ul><ul><ul><li>Teleconferencing </li></ul></ul><ul><ul><li>Security surveillance </li></ul></ul>
    3. 3. Objective <ul><li>Detection analysis with experimental data to compare the impact of various implementations of whitening process to enhance sound source detection. </li></ul>
    4. 4. Steered Response Power <ul><li>Robust algorithm </li></ul><ul><li>Especially in the presence of multiple interfering sources </li></ul><ul><li>Each point defined by a unique set of delays to the microphone array </li></ul>z
    5. 5. <ul><li>Signals received at each microphone aligned together by adding appropriate delay. </li></ul><ul><li>Coherent power is computed </li></ul><ul><li>Power estimate used for detection and localization. </li></ul>Steered Response Coherent Power
    6. 6. SRCP ∑ Compute Coherent Power (x,y,z) Uniquely defines (x,y,z)
    7. 7. SRCP … <ul><li>Power estimates get corrupted by noises </li></ul><ul><ul><li>Interfering sources and ambient noise (Uncorrelated) </li></ul></ul><ul><ul><li>Reverberations (Highly Correlated) </li></ul></ul>Coherent Summation Incoherent Summation
    8. 8. PHAT <ul><li>Phase Transform </li></ul><ul><ul><li>Spectral whitening </li></ul></ul><ul><li>Lower frequencies have higher contribution to signal power. </li></ul><ul><li>Higher frequencies also contains significant information (phase). </li></ul><ul><li>SRCP- PHAT is a measure of coherence and not the signal magnitude. </li></ul>
    9. 9. PHAT
    10. 10. SRCP – PHAT <ul><li>Works well with broad band signals </li></ul>
    11. 11. PHAT - β <ul><li>Speech is a combination of narrow and wideband signal. </li></ul><ul><li>β - Controls the extend of whitening </li></ul><ul><li>0 ≤ β ≤ 1 </li></ul><ul><li>This work aims to find the ideal value for β </li></ul>
    12. 12. Experimental Setup Speakers (sound source) Office Wall Microphones Field of View
    13. 13. Test Signals Used <ul><li>Broad band : 400Hz – 5600 Hz colored noise </li></ul><ul><li>Narrowband : 400Hz – 600 Hz colored noise </li></ul><ul><li>Sampling frequency of 16 kHz </li></ul>
    14. 14. Results
    15. 15. ROC <ul><li>Receiver Operation Characteristics </li></ul><ul><li>True Detection vs False Alarm </li></ul><ul><li>Area under the curve gives an Indication of decision making capability </li></ul><ul><li>Used in Biomedical, RADAR applications </li></ul>
    16. 16. Narrow band Broad band Low reverb. High reverb.
    17. 17. Conclusion <ul><li>PHAT – β out performs conventional PHAT in varied operating conditions </li></ul><ul><li>β ranging from 0.65 – 0.7 would give superior performance for speech signal </li></ul><ul><li>The results are in close agreement with the previous simulation studies. </li></ul><ul><ul><li>- Done by Kevin D. Donhue, J. Hannemann and H.G. Dietz </li></ul></ul>Signal type Low reverb. High Reverb. Narrow band 0.4 – 0.75 0.2 – 0.7 Broadband 0.65 – 0.9 0.6 – 1

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