In this note, gunshot detection solutions provider ShotSpotter speaks to asmag.com on how their technology works and how it has helped make cities safer from guns.
In this note, gunshot detection solutions provider
ShotSpotter speaks to asmag.com on how their technology works and how it has helped make cities safer from guns.
Gun violence is a serious issue in many countries. One example is the U.S., where citizens’ right to “keep and bear arms shall not be infringed” under the US Constitution 2nd Amendment (even though there’s prerequisite: “A well-regulated militia being necessary to the security of a free state”). Inevitably, this has led to endless gun-related tragedies in the U.S. According to Amnesty International, in 2017, some 39,773 died from gunshot injuries in America, an average of nearly 109 people each day.
That said, fast response to gun-related incidents has become critical for law enforcement in
metropolises. Yet they have encountered various challenges in this regard. “It is important to understand one of the key challenges facing police departments battling the gun violence epidemic today: According to the Brookings Institution
, over 80 percent of gunfire incidents are not reported to police through the traditional 9-1-1 system. Meaning, gunshot wound victims may not receive life-saving help, gun crime cases go unsolved, and law enforcement’s inability to respond to crimes can lead to normalized violence and community distrust,” said a spokesperson with ShotSpotter.
This is where ShotSpotter’s solution can come in handy. “ShotSpotter fills that data gap by alerting police of virtually all gunfire within the ShotSpotter coverage area within 60 seconds. This enables a fast, precise police response to help save the lives of gunshot wound victims and capture critical evidence at the scene,” the spokesperson explained.
How it works
ShotSpotter works by way of an array of acoustic sensors in designated coverage areas as determined by police departments based on historical gunfire and homicide data. On average, there are 20 sensors per square mile. Sensors are typically placed on taller structures – such as the tops of buildings and light poles – to maximize their range and avoid ambient street noise.
“ShotSpotter acoustic sensors are in many ways similar to a cell phone in that they are equipped with a small low power ARM processor, microphones and cellular radio. The signal from the sensor is analyzed in real-time to identify the loud, impulsive sounds – pops, booms and bangs – that are likely to be gunfire. These data are sent to the ShotSpotter cloud over a cellular wireless connection using a secure, private APN provisioned from one of the major cellular network providers,” the spokesperson said.
A certain amount of intelligence is used to make this work. “ShotSpotter uses a patented system of sensors and machine learning to detect, locate and classify gunfire. The sensors detect sounds, which are then located using a machine classification process called ‘multilateration.’ Multilateration is a straightforward mathematical computation to determine the time of the event, along with the longitude and latitude,” the spokesperson said.
“ShotSpotter then pulls the audio to create an image mosaic that represents the sound characteristics of the event along with various details about the incident, including the set of sensors that detected it. The resulting image mosaic, which is patented by ShotSpotter, is reviewed by a machine learning algorithm called ResNet, a third-party, open-source machine learning program for image classification. ResNet has been trained by ShotSpotter to determine the likelihood that an event is a gunshot,” he added. “This classification is then used as input by our highly trained human reviewers at ShotSpotter’s 24x7 Incident Review Center who listen to the sounds from the various sensors that detected the incident and analyze the sound waveforms. Our human reviewers make the final decision on whether or not an incident is published to the police as gunfire.”
According to the spokesperson, over the last two years ShotSpotter has maintained a 97 percent accuracy rate for real-time detections, including a 0.5 percent false positive rate aggregated across all customers. The technology can be integrated directly with multiple non-ShotSpotter technology platforms such as
PTZ cameras and even
drones, which can be automatically dispatched to the gun crime scene for reconnaissance before real officers arrive on the scene. ShotSpotter is not currently physically embedded with other devices such as IP cameras.
The solution has helped law enforcement throughout the U.S. fight crime and reduce gun violence. For example, Greenville, North Carolina and West Palm Beach, Florida, among others, both experienced reductions in gun violence injuries and homicides after ShotSpotter was deployed. The spokesperson also cited the following case study:
“In October 2021, former Oakland Police Captain, Ersie Joyner, was shot while pumping gas. Joyner endured 22 gunshot wounds, and in the critical moments while he laid on the ground at the gas station bleeding out, not a single onlooker called 9-1-1 for help. First responders were notified of the shooting by a ShotSpotter alert. Joyner said in a recent interview that ‘I tell people all the time there are five things that kept me alive and have me here right now today and those five things in this particular order are: God, ShotSpotter, the Oakland Police Department, Highland [Hospital] staff, and love and prayers.’”
‘Deserve rapid police response’
ShotSpotter’s customers include law enforcement agencies and campus and corporate security. The company mainly does business in the U.S. but also serves customers in the Caribbean and South Africa.
“All residents who live in communities experiencing persistent gunfire deserve rapid police response. Unfortunately, many communities outside of the United States are also experiencing an increase in gunfire incidents. Right now, ShotSpotter’s gunshot detection technology is being used in the Caribbean and South Africa as well, and we have plans to expand into Central and South America,” the spokesperson said.