Search-and-rescue teams and emergency services actively use drones during operations. Drones conduct reconnaissance, collect terrain data, deliver medicines and essential supplies to the affected areas. They can better reach and cover inaccessible and larger areas than rescuers on the ground or other types of vehicles.
Rescuers also equip drones with thermal imagers and night vision devices to search for people during disasters, such as earthquakes or shipwrecks, when every minute counts to find survivors.
Survivors typically plead for help by producing impulsive sounds, such as screams. Therefore, a team of engineers from Germany’s Fraunhofer FKIE institute has built a drone prototype designed to find people by detecting human screams and listening for other signs of distress. It’s actually something they set out to create to make it easier for first responders to find survivors following a natural disaster.
To create their drone, the engineers first recorded screams, knocks, and other sounds made by people in distress. They then analyzed the audio frequencies on the recordings, identified common markers, and trained the drone’s artificial intelligence algorithm to recognize them.
The team has developed an accurate acoustic system for filtering environmental and UAV noise in order to get positive detections on human screams or other impulsive sounds. It uses a particular type of microphone array, called Crow’s Nest Array, combined with advanced signal processing techniques to provide accurate locations of the specific sounds produced by missing people. The system components are minimized in quantity, weight, and size for the purpose of being mounted on a drone.
The Fraunhofer FKIE team conducted several successful open field tests in which their drone managed to estimate a victim’s location within a few seconds of picking up sound. As a next step, they plan to add a higher frequency microphone to a prototype to make it more precise at detecting sounds at farther away distances.
Researchers envision the listening drones saving lives by hearing sounds of survivors that may be buried under rubble from an earthquake or in a collapsed building.