It analyses key facial features and generates a mathematical representation of these features. It then compares them against the mathematical representation of known faces in a database, generating possible matches.
South Wales Police uses Facial Recognition Technology in the following cases:
Live Facial Recognition (LFR) compares a live camera feed of faces against a predetermined watchlist to find a possible match that generates an alert.
Retrospective Facial Recognition (RFR) is a post event use of facial recognition technology, which compares still images of faces of unknown subjects against a reference image database in order to identify them.
Operator Initiated Facial Recognition (OIFR) is a mobile phone use of FRT technology, which compares a photograph of a person’s face taken on a mobile phone to the predetermined watchlist to assist an officer to identify a subject.
Whenever we use Facial Recognition Technology, we recognise there is an ongoing need to balance privacy and protection concerns, in addition to considering its legal and ethical implications.
South Wales Police is testing its facial recognition algorithms with the Metropolitan Police Service and the National Physical Laboratory (NPL). Thanks to previous testing by the National Institute of Standards and Technology (NIST) we know that our Live Facial Recognition (LFR) system uses a high performing algorithm but we want to have an ongoing understanding of the performance of the technology we use, and to identify any impact on relevant characteristics, in particular race and sex.
This testing will further enable us to understand more about the algorithm's accuracy and if any biases have been detected. The data for these tests needs to be collected in a realistic operational policing environment and therefore this data will be collected whilst a number of LFR deployments are happening. The results of this testing will help inform SWP how we use facial recognition technology legally and fairly in order to prevent and detect crime, safeguard national security and keep our public safe..
What will the testing involve?
The testing will run alongside an authorised LFR operational deployment. Volunteers of all ages and backgrounds will walk past the facial recognition system along with members of the public.
After the testing is complete, the data from the volunteers and the CCTV footage will be kept SWP for a longer period than we would normally hold it for. This retention period is currently set at three years and is then subject to review.
This is so that after the deployments are completed, scientific and technology experts at the NPL can review the data and produce a report on how the algorithms have performed and how we may wish to use the new facial recognition algorithms in the future. We will make these findings public.
The data that has been collected may also be made available to the UK law enforcement community and its partners. The Metropolitan Police Service are also going to be undertaking similar testing with the NPL as part of this study.
Live Facial Recognition (LFR) compares a live camera feed of faces against a predetermined watchlist in real-time. It is used to locate persons of interest by generating an alert when a possible match is found.
How is Facial Recognition Technology used?
South Wales Police currently utilises NEC’s NeoFace facial recognition technology.
Before using LFR, a watchlist of offenders is created, that are wanted by the police and courts. The watchlist also includes people who may pose a risk of harm to themselves or others.
LFR cameras target an area and the images are streamed to the live facial recognition technology. The images are compared against the images in the watchlist. When the technology finds a possible match an alert is generated.
An officer then compares the camera image to the person they see and decides whether to speak to the person.
We will always explain why we have chosen to speak with someone, and give them an informational leaflet with contact details if they have further questions. Persons who are not included on a watchlist cannot be identified.
We will delete the images with alerts immediately after using them or within 24 hours. The images and biometric data of those who don’t cause an alert are automatically and immediately deleted. We record the CCTV footage that is used by the LFR technology and we keep it for 31 days.
Retrospective Facial Recognition (RFR) technology compares still images of faces of unknown people against a reference image database in order to identify them after an event.
How Retrospective Facial Recognition works
South Wales Police currently utilises NEC’s NeoFace facial recognition technology.
RFR is utilised post event as part of a criminal investigation. Images are typically supplied from CCTV, mobile phone footage or social media. These images are then compared against our custody images.
The reference database that is utilised by South Wales Police are custody images from South Wales and Gwent Police. These contain in excess of 600,000 images.
After a search is made, the technology reorders the reference image database from the most likely to the least likely possible match.
An operator will typically review the top 200 possible matches to decide whether a match has been made. If the operator determines a match has been made, they will inform the investigating officer. The investigating officer will review the match and add the person to the investigation as a suspect.
When is Retrospective Facial Recognition used?
RFR technology is used to assist with the investigation of a criminal offence in order to efficiently and effectively identify a suspect. When a suspect of a crime remains unknown, RFR will be used.
What is the Operator Initiated Facial Recognition (OIFR)?
The OIFR App is a mobile phone App of Facial Recognition technology. It compares a photograph of a person’s face taken on a mobile phone with facial images contained in a predetermined watchlist(s) in order to assist an officer to identify a subject.
How does the Operator Initiated Facial Recognition (OIFR) App work?
An image will be captured on an officer’s mobile phone and compared against a watchlist(s) selected by the officer. The watchlist available to the officer includes custody images held by South Wales and Gwent Police and missing persons from the South Wales Police area.
After a search is made, the technology reorders the chosen watchlist(s) from the most to least likely possible match. The six most likely possible matches are returned to the officer’s mobile phone. The officer will review the top six possible matches and decide whether a match has been made. If a match has been made it will then be possible to carry out further checks for the subject against police systems.
We will always explain to the person when we use the OIFR App and inform them how they can contact us to ask further questions.
Persons who are not included on a watchlist cannot be identified. The image, captured on the mobile device, and biometric data are automatically and immediately deleted after a search is carried out.
When is the Facial Recognition (OIFR) App used?
The OIFR App will not be used to replace traditional means of identification, such as having a conversation with the individual who gives their name or provides identification documents which are checked against police systems to identify a subject.
Wherever possible, the OIFR App will only be used after an interaction has occurred between the officer and the subject.
The OIFR App does not replace the existing RFR process but instead is used as an ‘on-street’ intelligence tool to assist the officers in identifying an unknown person.
Use of the OIFR App will only occur when the identity of a subject is not known and when there are reasonable grounds for its use.
Reasons for using Facial Recognition (OIFR) App: -
The subject is unable to provide their details because they are deceased, unconscious, have mental health or age barriers or incapable due to drink or drugs.
The subject has refused to provide their details
It is reasonably suspected that the subject has provided false details.
AND when one of the following grounds apply. When the subject is:-
Reported as a missing person
Suspected that they have committed an offence, wanted by the courts, subject to bail conditions or a court order.