Increasingly often, when mass shootings occur, bystanders are recording videos on their smartphones. Thanks to a new system, such footage could soon be used to determine the killer's whereabouts.
Developed by a team at Carnegie Mellon University, the technology is known as VERA. It requires video/audio from three or more smartphones that were recording the incident from different locations at the same time – this is likely to be the case when shootings occur at public events, such as the 2017 concert at the Mandalay Bay hotel in Las Vegas.
First of all, the system is able to determine where each phone was located within the environment – it does so based on the recorded images of known buildings and other structures. Next, it "listens" for two sounds within the audio track of each phone's footage.
The first of these sounds is the supersonic "crack" that occurs as the flying bullet breaks the sound barrier. The other is the muzzle blast that occurs as the cartridge explodes within the gun – although this sound is actually made before the supersonic crack happens, it reaches the phone's microphone second, due to the fact that it's only travelling at the speed of sound.
By analyzing the amount of time that elapsed between the recorded crack and blast, VERA is able to determine how far away the phone was from the gun. Then, by comparing the distances between all three phones' locations and the gun, it's also able to ascertain the direction that the gunshots came from.
Utilizing smartphone videos from the Mandalay Bay incident, the system was correctly able to determine the location of the gunman, based on just three gunshots that were recorded within the first minute of the massacre.
A similar system was previously developed at Vanderbilt University for military use, although it requires the phones to be equipped with special modules.
Source: Carnegie Mellon University via EurekAlert
