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UK Police Say 92 Percent False Positive Facial Recognition Is No Big Deal (arstechnica.com)
An anonymous reader quotes a report from Ars Technica: A British police agency is defending its use of facial recognition technology at the June 2017 Champions League soccer final in Cardiff, Wales -- among several other instances -- saying that despite the system having a 92-percent false positive rate, "no one" has ever been arrested due to such an error. New data about the South Wales Police's use of the technology obtained by Wired UK and The Guardian through a public records request shows that of the 2,470 alerts from the facial recognition system, 2,297 were false positives. In other words, nine out of 10 times, the system erroneously flagged someone as being suspicious or worthy of arrest.
In a public statement, the SWP said that it has arrested "over 450" people as a result of its facial recognition efforts over the last nine months. "Of course, no facial recognition system is 100 percent accurate under all conditions. Technical issues are normal to all face recognition systems, which means false positives will continue to be a common problem for the foreseeable future," the police wrote. "However, since we introduced the facial recognition technology, no individual has been arrested where a false positive alert has led to an intervention and no members of the public have complained." The agency added that it is "very cognizant of concerns about privacy, and we have built in checks and balances into our methodology to make sure our approach is justified and balanced."
In a public statement, the SWP said that it has arrested "over 450" people as a result of its facial recognition efforts over the last nine months. "Of course, no facial recognition system is 100 percent accurate under all conditions. Technical issues are normal to all face recognition systems, which means false positives will continue to be a common problem for the foreseeable future," the police wrote. "However, since we introduced the facial recognition technology, no individual has been arrested where a false positive alert has led to an intervention and no members of the public have complained." The agency added that it is "very cognizant of concerns about privacy, and we have built in checks and balances into our methodology to make sure our approach is justified and balanced."
despite the system having a 92-percent false positive rate, "no one" has ever been arrested due to such an error
I may have concerns about the civil liberty impact of broad-net surveillance systems in general, but the algorithmic deficiencies of this particular system are portrayed incorrectly in this article. I.e., the front-end of the system (the facial recognition system) has a 92% false positive rate, but together with the post-processing in the back-end, the total system has a false-positive rate of 0%. This is similar to saying that the object detection failure probabilities for a ADAS system need to be viewed in the context of the entire system, and it's the performance of the total system that is significant.
Rate of 8% successful, meaning almost 1 in 10 people are correctly identified. Not that bad.
Indeed. If you are looking for a suspect in a city of a million people, and this system flags 10 people, and upon double checking you find that one of the ten is the suspect, then that is pretty darn good.
The false positive rate, by itself, tells you nothing about the usefulness of a test.
Catching criminals is a side effect. The main purpose is to create justification to investigate anyone they want.