Signal enhancement for gunshot DOA estimation with median filters

The estimation of the direction of arrival (DOA) of gunshot sounds when the distance between firing and recording sites becomes large, as in a sniper scenario, tends to be degraded by low signal-to-noise ratio. Motivated by its ability to segregate harmonic and percussive parts in music processing, median filtering is used in this work to reduce noise level of gunshot signals prior to the operation of DOA estimation algorithms. Practical experiments with gunshot signals acquired by a microphone array indicate that the proposed pre-processing procedure leads to better results than spectral subtraction.