A blog post by ASTRIAL.
The evolution of audio surveillance systems has become increasingly pivotal in the modern era, with a limited yet diverse range of solutions available in the market, each equipped with unique features and capabilities. Acoustic information has emerged as a crucial tool in the prevention of criminal offenses. Through the utilization of analytics software, real-time audio data can be processed, enabling the detection of abnormal activities, behaviors, or incidents. The integration of audio data significantly enhances surveillance solutions, providing essential functionalities, particularly in scenarios where traditional video surveillance systems encounter limitations, such as hidden areas and low-light conditions.
Currently, operational audio systems utilize microphones and electronics to precisely detect suspicious sound events. Unlike radar or cameras, microphones do not require specific alignment, as they can effectively capture sound from all directions. Moreover, microphones do not necessitate a direct line of sight to the sound source, making them capable of capturing audible signals even when generated behind obstacles like buildings.
Configurable audio analytics software can trigger automatic alerts or actions when a microphone detects specific sounds such as screaming, glass breaking, or gunshots. This feature allows for early warnings, and accompanied by geolocation information, can facilitate swift reactions and interventions.
Recently, commercially available acoustic gunshot detection systems have been heavily promoted. However, concerns have been raised regarding their high annual costs, advertised efficiency, and reliability (Hansen & Boril, 2021). Limited independent technology validation studies are publicly accessible, leading to uncertainty about the actual performance of these systems. Controversy arises from a perceived gap between the materials advertised by manufacturers and the practical performance observed in real-world deployments. This underscores the need for transparency and accuracy of the information provided by vendors promoting acoustic audio detection technology.
Copyright: ASTRIAL GmbH
Developments within APPRAISE
In the APPRAISE project, the audio detection system is based on a novel design that locates a sound source using a microphone array and localisation algorithm. This system, with a given input of microphone location and directions of microphone arrays and their angles on the 360-degree coordinate system, processes identified sound location values in the form of alerts. These alerts seamlessly integrate with command-and-control systems, as well as information management systems. The approach to recognizing gunshots within the APPRAISE framework, replicating real-world conditions for soft target protection, has proven to be robust and efficient during deployment tests and beyond.
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The outdoor gunshot detection system developed and validated within the APPRAISE project by ASTRIAL GmbH demonstrates significant advancements in the field, offering several advantages:
- Operational Effectiveness in Noisy Environments:
- The system has undergone training, testing, and successful validation in real-world deployed APPRAISE field solutions.
- It has proven to be fully operational in noisy environments with high background noise, showcasing effective performance in both gunshot detection and localization.
- Customizability and Integration:
- Easily customizable provides real-time alerting and positioning information, facilitating immediate response on the location of detected abnormal activities or sounds to law enforcement agencies.
- Smoothly integrates with any command-and-control system and critical infrastructure information management system and allows for installation in a "plug and play" mode.
- Cost-Effective Monitoring:
- Each microphone array monitors a radius of up to 500 meters, efficiently covering the exterior of a given infrastructure against abnormal sounds.
- The system's cost is significantly lower than current market prices, making it a cost-effective solution with the potential for wide market penetration.
- High Precision Sound Source Localization:
- The sound source localization has been validated for increased accuracy and precision, advancing the state-of-the-art in this domain.
- Provides users with high-quality actionable intelligence for better decision-making.
- Expandability and Upgradability:
- The system is designed to be expandable and upgradable to address various types of abnormal sound events based on user needs.
- Accommodates changes or additions without requiring modifications to the existing installation.
- Comparable Performance to Military Systems:
- Achieves over 80% abnormal event detection performance, comparable to high-end and costly military systems.
In summary, the ASTRIAL-developed outdoor gunshot detection system within APPRAISE showcases notable advancements in terms of affordability, accessibility, adaptability, and performance, making it a valuable asset for enhancing security in various environments.
References
Hansen, J.H.L. & Boril, H., Convention Paper 10540, Gunshot Detection Systems: Methods, Challenges, and Can they be Trusted?, 151st Convention 2021 October.