What was the research project for the InfraredTags about?
Mustafa Doğa Doğan: Imagine you are at a store browsing different items — you’d like to get further information about the products you’re considering, the unit price, recipes, calorie information, or cheaper alternatives. Even though barcodes like QR codes are really cheap to manufacture and could be used to label items, they are typically visually distracting and not as durable as other tags like RFID, so they can easily become unreadable over time.
Thus, in the last decade, researchers have investigated several ways to insert tags that are imperceptible to the naked eye. However, prior research prototypes need either custom fabrication hardware or expensive/large detection tools to achieve invisible tags.
This is why we developed InfraredTags, a method to embed markers and barcodes in the geometry of the 3D printed object that does not require complex fabrication or high-cost imaging equipment. We accomplish this by using off-the-shelf fused deposition modeling (FDM) 3D printers and a commercially available infrared (IR) transmitting filament for fabrication, and a low-cost, off-the-shelf near-infrared camera for detection.
How are the tags brought into the product?
Doğa Doğan: The main geometry of the object is 3D printed using the IR-transmitting filament, while the tag itself is created by leaving air gaps for the bits. Because the main geometry is semitransparent in the IR region, the near-infrared camera can see through it and capture the air gaps, that means the marker, which shows up at a different intensity in the image. The contrast in the image can be further improved by dual-material 3D printing the bits from an infrared-opaque filament instead of leaving them as air gaps. Our method can embed 2D tags, such as QR codes and ArUco markers, and can embed multiple tags within the object, which allows for scanning from multiple angles while tolerating partial occlusion.