did i say that?? speech lab spring 2009 february 03, 09 1 montgomery college did i say that? did i...
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Did I say that?? Speech Lab Spring 2009
February 03, 09February 03, 0911
Montgomery Montgomery CollegeCollege
Did I Say That?Did I Say That?Automatic Keyword Spotting Using
Crosscorrelation
Uchechukwu Abanulo
In collaboration with Temple University Speech LabFunded by the US Air Force Research Lab, Rome, NY
Uche O. AbanuloPhysics, Engineering
And Geosciences
Did I say that?? Speech Lab Spring 2009
February 03, 09February 03, 0922
Montgomery Montgomery CollegeCollege
Presentation OutlinePresentation Outline
Uche O. AbanuloPhysics, Engineering
And Geosciences
• Research Goal• Applications of Research• Method• Preliminary Results
Did I say that?? Speech Lab Spring 2009
February 03, 09February 03, 0933
Montgomery Montgomery CollegeCollege
Research GoalResearch Goal
Applications
Method
Preliminary Results
Did I say that?? Speech Lab Spring 2009
February 03, 09February 03, 0944
Montgomery Montgomery CollegeCollege
Research Goal 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, 09February 03, 0955
Montgomery Montgomery CollegeCollege
System Specifications 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, 09February 03, 0966
Montgomery Montgomery CollegeCollege
IllustrationIllustration
Listening DeviceListening Device
Research Goal
Applications
Method
Preliminary Results
Did I say that?? Speech Lab Spring 2009
February 03, 09February 03, 0977
Montgomery Montgomery CollegeCollege
Research Goal
Applications
Method
Preliminary Results
Applications
Did I say that?? Speech Lab Spring 2009
February 03, 09February 03, 0988
Montgomery Montgomery CollegeCollege
Eliminate manual listening to terrorist or ‘enemy’ Eliminate manual listening to terrorist or ‘enemy’ conversationsconversations
Homeland SecurityHomeland 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, 09February 03, 0999
Montgomery Montgomery CollegeCollege
Commercial 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, 09February 03, 091010
Montgomery Montgomery CollegeCollege
Criminal Activity DetectionCriminal 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, 09February 03, 091111
Montgomery Montgomery CollegeCollege
MethodResearch Goal
Applications
Method
Preliminary Results
Did I say that?? Speech Lab Spring 2009
February 03, 09February 03, 091212
Montgomery Montgomery CollegeCollege
Cross correlationCross 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, 09February 03, 091313
Montgomery Montgomery CollegeCollege
Cross correlationCross correlation
Research Goal
Applications
Method
Preliminary Results
0 100 200 300 400 500 600 700 800 900 1000-5
0
5
Y
Illustration of Correlation
0 100 200 300 400 500 600 700 800 900 10000
0.5
1X
-1000 -800 -600 -400 -200 0 200 400 600 800 1000-1000
0
1000
XC
orr(y
)
-1000 -800 -600 -400 -200 0 200 400 600 800 10000
200
400
XC
orr(x
)
-1000 -800 -600 -400 -200 0 200 400 600 800 1000-50
0
50
Lag
XC
orr(x
,y)
Did I say that?? Speech Lab Spring 2009
February 03, 09February 03, 091414
Montgomery Montgomery CollegeCollege
ApproachApproach
Research Goal
Applications
Method
Preliminary Results
0 1 2 3 4 5 6
x 104
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
0.5
0 0.5 1 1.5 2 2.5 3 3.5 4
x 104
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
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.
xcorrxcorr
0 1 2 3 4
x 104
-20
0
20
Max power is not Max power is not around zero lag – not around zero lag – not position of keywordposition of keyword
2. Observe position of peak to see if it’s around the zero lag.
Yes: KeywordNo: Not keyword
3. Shift observed portion by a small amount and repeat process
If a portion is reached where If a portion is reached where the peak is close to the zero the peak is close to the zero
lag, then that’s where the lag, then that’s where the keyword is. keyword is.
If not, the utterance does not If not, the utterance does not contain the keyword.contain the keyword.
Did I say that?? Speech Lab Spring 2009
February 03, 09February 03, 091515
Montgomery Montgomery CollegeCollege
DemoResearch Goal
Applications
Method
Preliminary Results
Did I say that?? Speech Lab Spring 2009
February 03, 09February 03, 091616
Montgomery Montgomery CollegeCollege
ResultsResults
Research Goal
Applications
Method
Preliminary Results
0
10
20
30
40
50
60
70
80
Hits False Alarms
Did I say that?? Speech Lab Spring 2009
February 03, 09February 03, 091717
Montgomery Montgomery CollegeCollege
Uche O. AbanuloPhysics, Engineering
And Geosciences
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