Barcodes and QR codes feel like they’re everywhere nowadays, but they don’t have to be. Scientists at MIT have developed an invisible tagging system called BrightMarker, which embeds fluorescent tags into objects that can be viewed and tracked through an infrared camera.
Thrust into mainstream use thanks to the pandemic, QR codes can be pretty handy for jumping straight to a website from the real world by just scanning that little black and white box. They’re still commonly found on event posters to buy tickets, restaurant tables to view a digital menu, or linking to more info in museums and art galleries. But as innocuous as they may seem, they can be replaced with codes that link to scams or viruses. And one could make a case for them just being ugly and taking up room on an object.
That’s where MIT’s new BrightMarker comes in. The system essentially works the same way, but hides the code inside the object being tracked, so it can’t be tampered with – or even seen. But if you pass an infrared camera over it, suddenly the tag appears, along with the information it encodes.
In its current form, BrightMarker needs to be embedded directly into a 3D-printed object from the model stage. Using a software plugin, a BrightMarker tag is placed into the digital model and exported as an STL file. Then, using fluorescent filaments in the printer, an object with a hidden tag can be printed. They don’t change an object’s shape, function or appearance, the team says.
The fluorescent material those tags are made from emit light at near-infrared wavelengths, so they’ll show up in high contrast when viewed through infrared cameras. The team developed small hardware accessories that could be attached to smartphones or VR/AR headsets to detect the tags.
The team previously created InfraredTags, which functioned in a similar way. But they could only be used on black objects, and were harder to track because they didn’t stand out as much against background wavelengths of light. The new design works with multiple colors and has higher contrast for clearer views of the codes.
So what could you use this system for? The team says BrightMarkers could be used to track the history of an object, verification of authenticity, movements during shipping, or other uses that barcodes or QR codes currently fulfill.
But they could also be used for motion tracking systems in VR by, for example, embedding tags into wearables so a headset can monitor the location of a user’s hands and match them to their virtual character. Security-wise, they could also watch out for objects “moving” when they’re not supposed to (ie, being stolen). For privacy’s sake, extra filters can hide the surroundings and only see the tags.
They do, however, have their limitations. The main issue is that they can only track objects that are specially 3D-printed with the fluorescent tags embedded right inside, which limits their use cases. There’s also the nagging feeling that they’re more of a solution searching for a problem.
The research is due to be presented at UIST 2023 (PDF). The team demonstrates the tech in the video below.
Source: MIT
