DIGITAL COMMUNICATION & SIGNAL PROCESSING DESIGN 18-551 GROUP 9
A SHOT IN THE DARK Acoustic Point-Source Localization of a Gunshot Acoustic point-source localization of a sound has numerous applications, from voice tracking to beam steering. Identifying the location of a gunshot is a useful tool for law enforcement. Having sensor systems installed in high-traffic areas can give early warning of a crime in progress and increase the available information at the scene of a crime.
Texas Instruments C67 DSK with attached Educational DSP DSK_AUDIO4 and DSK6XXXHPI daughter cards
The critical steps of an implementable solution are real-time source detection and accurate estimation of time delays between microphones. Gunshot Signal
Source Ds4
Real-Time Source Detection
Ds2
Ds1
Time Delay Estimation
Ds3
Microphone 4
Microphone 2 Microphone 3
Far Field Solution
Near Field Solution
Microphone 1
The system uses differential times of arrival between microphones to estimate a point-source postion
PC
Spatial Estimate of Acoustic Point-Source
3
2
1 distance (meters)
A point-source is sampled and filtered in real-time to detect a gunshot. Once a gunshot has been detected, signal data is sent to a two-stage localization algorithm. Time delay estimates between each microphone are first computed using a generalized cross-correlation algorithm. These estimates are then used to compute a near field solution, using the linear Gillette-Silverman algorithm, and a far field solution of the localization problem.
0
-1
-2 -3 -3
Pranay Jain
Arda Orhan
Oren Wright
-2
-1
0 distance (meters)
1
2
3
A PC interface displays microphone positions and both near field and far field solutions