The city of Chicago has tested gunshot detection technology for the last few years, previous posts on this can be found here and here. The CPD tested systems from ShotSpotter, PSI (their SECURES technology was acquired by ShotSpotter in April 2009), and Safety Dynamics. According to an article in the Sun-Times in Oct 2009, the city conducted three separate tests of gunshot sensors between 2003 and 2007 in the West Side’s Harrison Police District. Only on one occasion did the detection system send a warning prior to a person calling 911 to report the shooting. As a result, the city felt the gunshot detection systems were too expensive at a cost of $200,000 a square mile.
This mixed success concurs with a similar study on the effectiveness of SECURES gunshot detection system (not ShotSpotter) released in 2008 (based on data from 2005-6).
Despite the lackluster results, the city is going forward with installing the technology in the Loop. It will cover all two square miles. The technology will allow for real time updates on shooters, while distributing this information remotely. The cost is expected to be around $400,000.
rshah Chicago, Gunshot Detection
[From ShotSpotter Hits the Suburbs as the Police Fight Gun Violence - NYTimes.com]
An article on ShotSpotter mentioned an independent study on gunshot detection.
In 2008, Peter Scharf, a criminologist at Tulane University in New Orleans, conducted a study for the National Institute of Justice about an early competitor of ShotSpotter, called Secures, in two Virginia cities. He found the system frequently sent the police on wild goose chases by reporting false positives, had an inconclusive effect on response time and, crucially, had little impact on arrest rates.
The report is very well done. Some of the interesting findings include how the gunshot detection system was negatively affected by radio frequency interference and fireworks/bottle rockets.
The report also discusses the tradeoffs between false positive and false negative error (an unavoidable part of these systems). The report found that “2/3 of SECURES®-related dispatches were “but-for false alarms” – both not a confirmed gunshot and no call corresponding call for service.
rshah Gunshot Detection
[From San Francisco Chronicle, S.F. board panel imperils crime-watching gear]
A 3-2 vote in San Francisco is cutting $360,000 that Mayor Newsom sought for installations and repairs of the anti-crime devices, i.e., cameras and gunshot sensors. The cut was motivated by the lack of evidence that the cameras and sensors were effective. This decision could still be reversed and it doesn’t affect all the camera/gunshot systems in the city.
The anecdotal evidence seems to show that gunshot systems are useful. Its unfortunate that there isn’t hard data to support the use of gunshot systems. I am afraid that these useful systems will be muddied by the less effective surveillance cameras.
rshah Gunshot Detection, Other Cities
[From City picks gunshot detection system - NJ.com]
Newark has chosen Shotspotter for a gunshot detection system over competing systems from Safety Dynamics (SENTRI) and Planning Systems (SECURES).
Gunshot detectors will be mounted on structures over a 7-square-mile area. When triggered, Shotspotter sensors will provide police with the location, number of shooters, and number of shots fired. . . . Shotspotter’s Gunshot Location System has also been installed in 27 cities around the country, including Washington, D.C., and East Orange. Newark’s neighboring municipality first introduced gunshot detectors made by Planning Systems Inc. in 2005, and deployed a Shotspotter system in 2006, according to Detective Andrew DiElmo of the East Orange Police Department. Both systems are in operation in East Orange.
Gunshot detectors are viewed as a “useful tool” for investigative purposes, and the East Orange police also considers it a crime deterrent, DiElmo said. However, there have been issues about gunshots that go undetected by sensors. “Does it work 100 percent of the time? No,” said DiElmo. “We have had incidents where the sensors haven’t alerted us.”
rshah Gunshot Detection, Other Cities
From SecurityInfoWatch.com:
A good article on the state of gunshot detection technology. It notes that 16 cities have installed ShotSpotter. A study in 1999 found the detection system to be accurate 80 percent of the time within 25 feet.
It also highlights some “success stories”:
Less headline-grabbing are the cases seen in Minneapolis since installing ShotSpotter last month. Police have netted three felons, two semiautomatic guns, and recovered one stolen car. It also provided additional information in three shooting cases. “It’s just a better compass. It still takes good cops, persistent investigation, and good police skills,” says Lt. Gregory Reinhardt, spokesman for the Minneapolis police department. “It’s just pointing us in a better direction.”
However, Lt. Reinhardt admits that none of the arrested felons and confiscated items were necessarily involved in the original shooting. In one case, police arrived to find a car speeding off. Police pursued, then apprehended a suspect – a convicted felon – who tried to flee. In the car was a loaded semiautomatic pistol. In two other cases, police arrived to find people loitering. On each occasion they took names and found a person wanted on a warrant. “It’s sort of hard to fathom that the purpose of the thing is to put police in a place where they can pick up people who are wanted on other warrants,” says Mr. Yohnka.
A final interesting point concerns data security:
Data security will be one of the first questions. The entire system uses encryption, from sensor to server to dispatcher, says James Beldock, president of ShotSpotter. The server stores a record of each gunshot report that includes the time, the sensor readings, and calibration data.
rshah Gunshot Detection
From Washingtonpost.com:
An article on the ShotSpotter gunshot detection technology being in in Washington DC. Its funded by the FBI as a test case to see if gunshot detection technology can help reduce shootings.
A few notes:
1. You get an immediate response by police with ShotSpotter, unlike with video cameras that are often not constantly monitored by police.
2. It appears police officers trust and believe in the technology. As a result, they are responding to gunshots more often. This shows how technology can mobilize manpower.
3. Cost – the rollout of 48 cameras costs hundreds of thousands and it would cost millions to wire the entire city.
4. It doesn’t say if there are any other possible uses of the gunshot detection systems.
rshah Gunshot Detection, Other Cities
From The Enquirer:
A nice article on what Cincinnati is doing to roll out a 100 camera network with gunshot detection and a fiber optic grid. Its going to cost millions and take a while. Hopefully it will work better than their previous attempt:
The city bought 40 surveillance cameras in 2003 as part of a pilot program in six neighborhoods that never really took off. The cameras were never useful, in part because they ran over the public Internet and were very slow, often producing “video” that was so slow that it looked more like single-frame still shots. Those cameras are no longer used.
They also have a nice pdf of how gunshot detection works. And according to Jose Cordero, director of police in East Orange, the gunshot technology helps reduce gun crime:
Jose Cordero . . . said his department bought a system in 2005 and heavily publicized the new technology in the media, particularly the neighborhoods where cameras were installed. The result is that gun crime in those areas is down 85 percent, he said.
rshah Gunshot Detection
A story on gunshot detection camera system (SENTRI) is in Government Technology. It covers the basics on how the system works and its creators. The best nugget comes out of the discussion on the chicago deployment and notes that it is currently in a pilot state.
“Pilot stage is really a technical term,” said Bryan Baker, chief executive officer of Safety Dynamics, which produces the gun recognition technology. “When they define something as a pilot, that means there’s still a certain confidentiality about information. Once it gets reclassified as production and not pilot, then all the information becomes nonconfidential.”
So maybe once its out of pilot state, the rest of us will get more data on how well these systems are operating. The article also suggests what the next step maybe in these systems:
Several companies are creating a video analysis component that would recognize a shooting scene — the position someone would be in when holding a gun, someone lying on the ground or a group of people running. “They can digitize what somebody holding a gun would look like,” Baker said. “Then they can lock in and follow him. When you put all these things together, it can be successful in protecting parameters. You make it increasingly difficult for an intruder to escape notice.”
rshah Gunshot Detection
From CNET News.com:
Another gun shot detection system, called Redowl from iRobot, however this one is designed to be mobile (it works with the Packbot). Some quotes from the article:
the company announced a prototype system designed to pinpoint incoming rounds from rifles and mortars, and also to provide surveillance and targeting capabilities. The remote-controlled gear, named Redowl (short for “robot enhanced detection outpost with lasers), is designed to work with iRobot’s PackBot combat device.
Redowl features a laser pointer and illuminator, an acoustic localizer and classifier, a thermal imager, GPS (Global Positioning System), an infrared and daylight camera, and two wide-angle cameras. iRobot, which also makes the Roomba household vacuum robot, developed the Redowl system in conjunction with the Photonics Center at Boston University.
In field tests, the PackBot-Redowl combination had a success rate of 94 percent in locating the source of rounds fired from 9mm pistols, and M-16 and AK-rifles, at a range of more than 100 meters, the company said.
rshah Gunshot Detection, Vendors
From Northwest Indiana News:
After a successful pilot program, Chicago officials have installed 30 of the devices alongside video surveillance cameras in high-crime neighborhoods, with 12 more on the way, and dozens more to follow, Baker said.
In Los Angeles County, the sheriff’s department plans to deploy 20 units in a pilot test, and officials in Tijuana, Mexico, recently bought 353 units, Baker said. Police in Philadelphia and San Francisco are close to launching test programs of their own, and New Orleans and Atlanta have also made inquiries.
SENTRI is the brainchild of Safety Dynamics and Dr. Theodore Berger, director of the Center for Neural Engineering at the University of Southern California in Los Angeles. Each SENTRI contains a library of acoustical patterns, or “sound signatures,” which Berger developed over several years.
Four microphones in the system differentiate gunshots from other noises like traffic and construction by measuring the unique decibel level of a bullet being shot out of a gun, and comparing the sound to its library. That way, a gunshot would activate the system, but a siren or a car backfiring would not, Baker said.
Adding the SENTRI to an existing surveillance camera is not cheap. The system costs between $4,000 and $10,000 per unit, but in Chicago they and the accompanying cameras are paid for with forfeiture money.
rshah Chicago, Gunshot Detection
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