Did I say that?? Speech Lab Spring 2009 February 03, 09 1 Montgomery College Did I Say That? Did I Say That? Automatic Keyword Spotting Using Crosscorrelation Uchechukwu Abanulo In collaboration with Temple University Speech Lab Funded by the US Air Force Research Lab, Rome, NY Uche O. Abanulo Physics, Engineering And Geosciences

Did I say that?? Speech Lab Spring 2009 February 03, 09 2 Montgomery College Presentation Outline Uche O. Abanulo Physics, Engineering And Geosciences Research Goal Applications of Research Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, 09 3 Montgomery College Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, 09 4 Montgomery College Research Goal Keyword or Key-phrase detection – –Did the speaker say __________? Keyword or Key-phrase Identification – –What portion of the utterance contains ___________? Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, 09 5 Montgomery College System Specifications Speaker independence Minimum utterance length – 2 seconds Noise/Interference Robustness Confidence Level Outputs Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, 09 6 Montgomery College Illustration Listening Device Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, 09 7 Montgomery College Research Goal Applications Method Preliminary Results Applications

Did I say that?? Speech Lab Spring 2009 February 03, 09 8 Montgomery College Eliminate manual listening to terrorist or ‘enemy’ conversations Homeland Security Automatically detect when targeted persons or groups utter certain flag words Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, 09 9 Montgomery College Commercial Automatically search through speeches of important personnel for certain words or phrases Automated response systems Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, Montgomery College Criminal Activity Detection Monitoring inmate conversations Detection of use of unpermitted words Automatic searches for flag words Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, Montgomery College Method Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, Montgomery College Cross correlation Measure of similarity between two signals Two signals compared by –Sliding one signal by a certain time lag –Multiplying both the overlapping regions –Repeating the process and adding the products until there is no more overlap If both signals are exactly the same, there’s a maximum peak at the time = 0, and the rest of the correlation signals tapers of to zero Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, Montgomery College Cross correlation Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, Montgomery College Approach Research Goal Applications Method Preliminary Results 1. Let the length of the keyword or phrase be n. The cross correlation of the keyword and the first n samples of the utterance is computed. xcorr Max power is not around zero lag – not position of keyword 2. Observe position of peak to see if it’s around the zero lag. Yes: Keyword No: Not keyword 3. Shift observed portion by a small amount and repeat process If a portion is reached where the peak is close to the zero lag, then that’s where the keyword is. If not, the utterance does not contain the keyword.

Did I say that?? Speech Lab Spring 2009 February 03, Montgomery College Demo Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, Montgomery College Results Research Goal Applications Method Preliminary Results

Did I say that?? Speech Lab Spring 2009 February 03, Montgomery College Uche O. Abanulo Physics, Engineering And Geosciences