AI has many potential roles in law enforcement that can improve security and safety for all. One example can be seen with security-scanning systems currently being installed in some prisons to prevent the smuggling of contraband and other prohibited and potentially dangerous items. They combine safe millimetre-wave scanners, which are already widely used for passenger security checks at airports, with new AI models that are specially trained to detect threats that are relevant to the prison environment.
A Proven Technology with More to Offer
Advanced millimetre-wave scanners have quickly become a familiar sight for air travellers and have changed the security check-in experience, reducing false alarms as well as improving detection of suspicious items. The technology inside is harmless to the human body, as well as preserving privacy, and scanning is fast and informal.
The team behind the Rohde & Schwarz QPS (Quick Personnel Security) scanners has discovered the potential of millimeter wave scanning – vigilance, speed, privacy and safety – for use in prisons. To help tailor the solution to meet the specific needs of this environment, they reached out to a prison operator willing to help with development and testing.
Safe, Smart, Private
Scanning with millimetre waves can detect hidden objects concealed under and within clothing. While able to penetrate clothing, the waves are reflected by the skin and are harmless to body tissue. They can detect many different types of materials including metals and non-metals such as liquids and powders, so they can help detect forbidden items. In the past, prison staff would need to carry out a full body pat down which are invasive and pose a security risk to staff that may be more vulnerable whilst they carry out the search. By using a scanner, there is no contact required and the natural arms down pose required for scanning that makes airport checks so natural and easy, can work well in prisons too as it is unchallenging and can help to keep the mood calm.
R&S QPS scanners contain an array of millimetre-wave transmitters and receivers that are activated in a sequence. This enables the system to be quiet, fast, and ultra-reliable.
The reflected waves, picked up by the receivers, are handled with powerful digital signal processing to produce a coherent dataset. Within this data lies the evidence of any unusual items. These could be inoffensive objects such as credit cards, memory cards, or papers, or they may be threats such as firearms and knives.
Objects that are not contraband, such as buttons or zippers, will not confuse the R&S QPS scanner. While the millimetre wave scanner detects everything, the algorithm takes care of distinguishing, understanding, and assessing that these are not threats. Here’s where the specially trained AI makes the difference, spotting the digital footprints among the mass of “normal” background data.
If anything is discovered, the system pinpoints its location on the body using a generic avatar image displayed on-screen. Security staff can then carry out a targeted search. This all happens without creating any facial or body images of the person being scanned, ensuring privacy at all times.
Training for New Threats
As the threats encountered in prisons are different to those expected at an airport, the AI algorithms developed to safeguard air travel needed retraining to meet the specific needs of prison operators. Security staff are always on the lookout for weapons like improvised plastic stabbing implements, as well as items that ordinary members of the public can carry quite legitimately. Drugs are another obvious target and, in prison, are often transported in small syringes or vials that can be difficult to find or dissolved in liquids to avoid detection. Others include specialized gadgets, like ultra-miniature Bluetooth cell-phones that are the size of a fingertip yet provide full communication functionality, and would also avoid detection with traditional methods. Security checks are also needed at multiple locations to prevent visitors from smuggling prohibited items and substances from outside, as well as preventing the distribution or movement of items between different areas within the prison.
Training the AI involves conducting large numbers of scans of people without contraband and then doing the same recordings of people with contraband, to drive the machine-learning process. Items are hidden in locations across the entire body. When testing confirms the required accuracy has been achieved, with extremely high detection rates and minimal false alerts, the training is complete and the model can be duplicated and deployed to as many systems as are needed.
As part of this process, teaming up with the prison network operator provided invaluable expertise for testing the newly retrained models. The algorithms, test criteria, and methodology used are, of course, closely guarded secrets. It’s enough to say that the algorithms were designed and tested with every possible threat and every conceivable smuggling technique in mind.
R&S QPS201 scanners are being installed throughout the prison, at visitor entrances and at sensitive or strategic locations such as restricted areas, to prevent illegal activities: from drug dealing and prohibited communications to intimidation and violence. In addition, the scanners of several prisons can be networked using an R&S QPS server to combine and compare their statistics and use the results to identify possible outliers.
Keeping the Pace of Progress
As security threats are always evolving, it’s important to keep improving and expanding the detection capabilities. Rohde & Schwarz is therefore committed to regularly providing comprehensive software updates. As the algorithms run on powerful processors at the heart of R&S QPS systems, continuous improvement unleashes more of the potential from these resources. By providing this assurance, Rohde & Schwarz has been awarded the DrugDetect Program for Prisons in Europe.
The R&S QPS201, enhanced with AI specially optimized for prison authorities, is now in action and helping maintain a safe environment for staff and prisoners. It is considered proportionate and understood as respecting privacy. It provides both protection and enforcement.
