New handheld device helps detect hidden injuries on darker skin, offering hope for better prosecutions in abuse and violence cases
It’s about the size of an iPad. But police say it might change how justice is served—especially for those whose injuries are often invisible to the eye.
The Metropolitan Police has begun deploying a new device that uses advanced imaging to detect bruising on victims of assault, particularly those with darker skin, where injuries can go unnoticed by standard methods. The move, backed by early results from a pilot program in South London, is being hailed by frontline officers and victim advocates alike as a potential turning point in the fight against underreported violence—especially against women and children.
The device, which relies on cross-polarisation technology, sharpens the contrast in photographs and cuts glare, making injuries stand out clearly even when bruises appear faint in natural light. It’s the first time this imaging technology has been adapted into a portable tool for field officers.
Justice that Sees Everyone
For decades, people with darker skin have had to fight twice—first to survive the violence, and then to prove it happened.
Bruising, especially on Black and South Asian victims, often doesn’t show up clearly on photographs taken under standard conditions. That lack of visible evidence can make or break a prosecution, particularly in domestic violence cases where testimony is already hard to come by.
“This is a big deal. Finally, we’re seeing investment in tools that account for racial disparities in healthcare and justice,” said Sarah Ashiru, a solicitor specializing in victim advocacy in London. “For years, women of colour have reported being dismissed, told their injuries weren’t visible enough. This technology might not solve everything, but it’s a leap forward.”
During the Met’s pilot program earlier this year, the device was used in 33 separate incidents. Police say it directly contributed to charges being brought in nearly half of those cases. Other investigations are ongoing.
One officer involved in the pilot said it made an immediate difference. “The images I was able to capture really highlighted the injuries caused to a young child. Without the tool, you’d barely notice anything. But through this lens, you saw the full extent of the bruising.”
The Tech Behind the Black Frame
The device may look like a tablet, but it’s been engineered for a very specific job.
Cross-polarisation—a technique more common in lab research or forensic photography—uses filters to block light reflecting off the skin’s surface. That glare reduction helps expose subdermal injuries that otherwise blend in. Bruises that haven’t darkened yet—or that are barely visible due to melanin—can suddenly appear clear and sharp.
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Size of device: About 11 inches wide, similar to an iPad Pro
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Weight: Under 1 kg
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Image output: High-contrast, glare-reduced, suitable for evidence submission
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Time to scan: Instant capture with automated enhancement algorithms
Officers said the biggest advantage wasn’t just how well it worked—but how fast. “You don’t have to drag someone to a hospital for scans anymore,” said another officer involved in the trial. “You literally hold it up, and you get what you need.”
A Boost for Convictions, But Questions Remain
The Met says the device will now be deployed across custody suites and frontline patrols, particularly in high-risk boroughs where assault reporting is frequent.
The hope is that clearer images will lead to more robust case files, better CPS support, and ultimately, higher conviction rates.
But some experts are urging caution. “Technology is only part of the puzzle,” said Dr. Leanne Duncombe, a criminologist at the University of Leeds. “Without trauma-informed policing, better victim support services, and faster court processing, we risk placing too much faith in tools, not systems.”
Still, she admitted, the data looks promising. A 45% charge rate from the trial, she noted, “is not insignificant.”
Here’s a quick comparison of typical evidence outcomes with and without enhanced bruise imaging:
| Metric | Without Tech | With Tech (Pilot Avg) |
|---|---|---|
| Charges Filed | ~22% | 45% |
| Image Usability for CPS | Low | High |
| Time to Capture Usable Photo | ~15 mins | <1 min |
| Victim Satisfaction Reported | Unknown | Increased (Anecdotal) |
Frontline Officers Say It Changes Everything
Constables and custody staff alike have praised the ease of use and emotional impact of having visual proof when comforting victims.
“Sometimes the bruise isn’t the only thing hidden,” said one Met officer in Croydon. “Victims feel like they’re not believed. When you show them what the camera picked up—they tear up. It’s validating.”
Another officer described a recent assault case involving an elderly man where the device revealed blunt force trauma on his back that wasn’t visible during the initial assessment. That evidence later became central to charges filed against his carer.
Not every case ends in prosecution. But officers say this tool helps victims feel heard—something that’s long been missing from the system.
A Focus on Women, But Impact Could Be Broader
The Met has placed a special emphasis on how this device could help combat violence against women and girls—a national policing priority. But its applications reach far wider.
From elder abuse and hate crimes to injuries suffered in police custody, having clearer visual documentation helps build stronger, fairer cases.
And for communities that have historically distrusted the police, it’s a small but powerful gesture.
“This isn’t just about seeing bruises,” said Ashiru. “It’s about seeing people who’ve been ignored.”
