Signal enhancement for gunshot DOA estimation with median filters

Borzino, A. M. C. R.; Apolinario, J.A.; Campos, Marcello L. R. de; Biscainho, Luiz W. P.

doi:10.1109/lascas.2015.7250439

Cited by 6 publications

(8 citation statements)

References 12 publications

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“…When signals of interest are approximately stationary, such as tiny voice snippets, whistles, or white noise, methods based on noise correlation matrix estimation, such as Wiener Filtering [36], are used. For impulsive signals, as in the case of gunshot signals, median filtering is an alternative option [5]. In this work, we evaluate the performance of these methods in the task of DoA estimation.…”

Section: Doa Estimation and Shooter Localizationmentioning

confidence: 99%

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Gunshot Airborne Surveillance with Rotary Wing UAV-Embedded Microphone Array

Serrenho

Apolinario

Ramos

et al. 2019

Sensors

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Unmanned aerial vehicles (UAV) are growing in popularity, and recent technological advances are fostering the development of new applications for these devices. This paper discusses the use of aerial drones as a platform for deploying a gunshot surveillance system based on an array of microphones. Notwithstanding the difficulties associated with the inherent additive noise from the rotating propellers, this application brings an important advantage: the possibility of estimating the shooter position solely based on the muzzle blast sound, with the support of a digital map of the terrain. This work focuses on direction-of-arrival (DoA) estimation methods applied to audio signals obtained from a microphone array aboard a flying drone. We investigate preprocessing and different DoA estimation techniques in order to obtain the setup that performs better for the application at hand. We use a combination of simulated and actual gunshot signals recorded using a microphone array mounted on a UAV. One of the key insights resulting from the field recordings is the importance of drone positioning, whereby all gunshots recorded in a region outside a cone open from the gun muzzle presented a hit rate close to 96%. Based on experimental results, we claim that reliable bearing estimates can be achieved using a microphone array mounted on a drone.

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Section: Doa Estimation and Shooter Localizationmentioning

confidence: 99%

“…The successful use of microphone arrays to tackle the direction-of-arrival (DoA) estimation problem even with low signal-to-noise ratio (SNR) can be seen in Reference [5]. In this paper, median filtering is used to enhance the collected acoustic gunshot signals.…”

Section: Introductionmentioning

confidence: 99%

Gunshot Airborne Surveillance with Rotary Wing UAV-Embedded Microphone Array

Serrenho

Apolinario

Ramos

et al. 2019

Sensors

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“…There are a myriad of methods that can be employed in signal enhancement (SE) applied to gunshot signals. For instance, adaptive filtering, spectral subtraction, and median filtering [16], [17], [18]. As one of the main goals in this paper is to estimate DoA from noisy signals, it is natural to consider signal enhancement as a way to improve estimations.…”

Section: B Signal Enhancementmentioning

confidence: 99%

“…Borzino [18] proposed the use of median filtering (MF) to enhance gunshot signals. Median filtering has been used to enhance harmonic parts of music by removing undesired impulsive signals.…”

Section: B Signal Enhancementmentioning

confidence: 99%

Investigating the potential of UAV for gunshot DoA estimation and shooter localization

Fernandes¹,

Borzino²,

Ramos³

et al. 2016

Anais De XXXIV Simpósio Brasileiro De Telecomunicações

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This paper presents an approach to obtain stationary shooter localization in a Cartesian plane using a moving array of microphones. A single array is embedded in an unmanned aerial vehicle (UAV), a quadcopter, to explore benefits provided by its intrinsic mobility. We propose a model which is based on geometrical acoustics and that assumes the gunshot signals as being buried in strong noise generated by propellers. Generalized cross correlation algorithms are used to estimate the Direction of Arrival (DoA) of the impulsive gunshot signals and, finally, bearings-only target motion analysis techniques are applied to estimate potential shooters localization from the noisy DoAs.

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“…However, the use of drones in this application brings a new complication by worsening the SNR of the signals of interest caused mainly by the noise from the propellers. Therefore, the use of signal enhancement techniques such as adaptive filtering, spectral subtraction, and median filtering [5], [6], [7], [8], may be needed to improve the SNR prior to applying the algorithms for DoA estimation. A preliminary discussion on this issue has been presented in [4].…”

Section: Introductionmentioning

confidence: 99%

Bearings-only aerial shooter localization using a microphone array mounted on a drone

Fernandes

Apolinario

Ramos

2017

2017 IEEE 8th Latin American Symposium on Circuits &Amp; Systems (LASCAS)

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Estimating the direction of arrival (DoA) of an audio signal from an aerial platform gives way to estimating the source localization. This paper addresses the problem of airborne shooter localization using a microphone array mounted on a drone. In this scenario, the noise of the propellers poses a great level of difficulty in estimating the DoA of the gunshot signals owing to low levels of SNR. This, combined with the fact that a moving drone records multiple gunshots at different positions, have discouraged the use of drones for shooter localization. Based on real gunshot signals recorded at a shooting site, we explore the advantages and limitations of using a drone for the task of audio surveillance and gunshot detection and localization.

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Signal enhancement for gunshot DOA estimation with median filters

Cited by 6 publications

References 12 publications

Gunshot Airborne Surveillance with Rotary Wing UAV-Embedded Microphone Array

Gunshot Airborne Surveillance with Rotary Wing UAV-Embedded Microphone Array

Investigating the potential of UAV for gunshot DoA estimation and shooter localization

Bearings-only aerial shooter localization using a microphone array mounted on a drone

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