A US company that uses acoustic sensors and machine classification to identify and time-stamp “impulsive” noises has won a three-year contract with the city of Chicago to track gunshots across 100 square miles.
ShotSpotter says it allows police departments to respond faster to gunshot incidents, citing research that shows 80 percent of gunshot incidents in urban areas are not reported to police with a 911 call.
The $23 (£17.7) million contract comes as a global report by the University of Washington’s Institute for Health Metrics shows the US reported 37,200 gun deaths in 2016 alone; the second only to Brazil.
The company provides intelligent indoor and outdoor gunshot sensors that link to a cloud and subscription-based service for customers, with an API that supports integration with other customer systems like security video management.
Gunfire alerts are pushed to mobile, desktop and browser apps, SMS or email.
ShotSpotter now has both Chicago and New York City under contract to 2021.
“ShotSpotter has proven to be a key element of our gun violence reduction strategy and we rely on the company as a trusted technology provider to the city of Chicago and our law enforcement professionals,” said Eddie Johnson, Superintendent of the Chicago Police Department in a release shared Thursday.
ShotSpotter: How Does it Work?
The software filters out ambient background noise, such as traffic or wind, and looks for impulsive sounds characteristic of gunfire. If it detects such a “pulse” it analyses features from the waveform like sharpness, strength, duration and decay time.
The sensor then sends these features to the company’s cloud servers as part of a data packet that includes the location coordinates of the reporting sensor and the precise time-of-arrival and angle-of-arrival of the sound.
The company’s algorithms run against both such pulse features, the distance from the sound source, pattern matching and other heuristic methods to evaluate and classify the sound, with its machine classifier trained and validated against a large database of known gunfire and other “impulsive” community sounds.
“This contract represents a huge vote of confidence in ShotSpotter from the city of Chicago and we are proud to be a valued partner in helping them respond to gun violence across this great city,” said Ralph Clark, President and CEO of ShotSpotter.
NASDAQ-listed ShotSpotter has seen its share price nearly quadruple during calendar 2018, rising from $14.30 in early January to the $58 region this week.