IR-Blocking Eyewear and Retroreflective Clothing: Attacking the Sensor Instead of the Model
Much biometric capture uses near-infrared — 3D face mapping, iris scanning, night CCTV illuminators. Reflectacles (Scott Urban, 2015) absorb most near-IR at 780–1400 nm so eyes vanish on IR cameras while looking like ordinary sunglasses; Japan's Privacy Visor instead uses IR LEDs to blind cameras. Retroreflective fabric returns flash straight to the lens, overexposing the wearer — but needs a light source co-located with the camera, so it does nothing against ambient-light video.
Attacking the sensor rather than the model is the more durable half of counter-surveillance, because physics cannot be retrained. It is also the narrower half — each technique defeats one specific capture mode. ## Infrared-blocking eyewear A large proportion of biometric capture relies on **near-infrared** rather than visible light: 3D face-mapping systems (of the kind used for phone face unlock), iris scanners, and the infrared illuminators on night-capable CCTV. **Reflectacles**, developed by Scott Urban and sold since 2015, are glasses whose lenses absorb or reflect the great majority of near-infrared in roughly the 780–1400 nm band. To a human they look like ordinary sunglasses. To an infrared camera the wearer's eyes disappear into black, or the head becomes a halo of reflected light — defeating IR face-mapping and iris capture and degrading night CCTV. Japan's **Privacy Visor**, developed at the National Institute of Informatics by Isao Echizen, took the opposite approach: near-infrared **LEDs** mounted on eyewear, invisible to humans, that overwhelm the camera with glare. The limitation is precise: these work against systems that use infrared. They do nothing against ordinary daylight video, and IR-LED approaches fail against cameras with infrared-cut filters. ## Retroreflective and anti-flash clothing **Retroreflective** materials return light directly toward its source rather than scattering it. A fabric with this property — the ISHU anti-paparazzi scarf being the best-known commercial example — returns a camera flash straight into the lens, blowing out the exposure so the wearer appears as an overexposed white blob. The limitation is that it needs a light source **co-located with the camera**. It works against flash photography and against IR-illuminated night cameras. It does nothing against ordinary ambient-light video, which is most video. Infrared LED hats and caps use the same logic in the other direction: bright IR LEDs, invisible to human eyes, create glare that obscures the face on IR-sensitive cameras. They fail in daylight and against IR-cut-filtered sensors. ## Why this layer is more robust but not sufficient Nothing here depends on what model runs downstream, so none of it expires when a system is retrained — a real advantage over Adversarial Fashion: Clothing and Makeup That Attack Computer Vision. But each technique covers one modality. Comprehensive coverage would require defeating visible-light video, infrared, thermal imaging, gait analysis and device-signal tracking simultaneously, and no wearable does that. See Anti-Camera Technology: What Actually Works and What Is Still Fiction.