Through-wall Imaging Technology allows users to see through obstacles using Wi-Fi signals. A research team at Carnegie Mellon University has developed this technology based on a Wi-Fi router, enabling users to see through various types of walls. This technology can be utilized in emergency applications.
The system developed by the Carnegie Mellon University research team allows observation of people or moving objects in a room through Wi-Fi signals. (Photo: iStock)
Researchers have been exploring ways to “observe” individuals without using cameras or expensive LiDAR scanners for many years. In 2013, a research team at the Massachusetts Institute of Technology (MIT) discovered how to use mobile phone signals to see through walls. In 2018, another research team at MIT used Wi-Fi to detect people in a different room and represented their movements through stick figures. Currently, the researchers at Carnegie Mellon University are creating a system for through-wall imaging using Wi-Fi.
Researcher Jiaqi Geng and colleagues developed a method for detecting the three-dimensional shape and movement of a human body in a room using only a Wi-Fi router. The team utilized DensePose, a system that maps all pixels on the surface of a human body in an image. Essentially, this method records a coordinate system for each joint to describe human posture. They then designed a deep neural network to combine the phase and amplitude of Wi-Fi signals transmitted and received by the router with the coordinates on the human body.
This technology operates by transmitting low-power Wi-Fi signals through walls and reflecting around the room. This signal detects all objects in the room, excluding static objects. When the signal bounces back, the system uses the reflection from moving objects to create radar-like images. The system can be applied to drywall, wooden fences, and even concrete walls, although its range and accuracy depend on the type of wall. According to the research team, Wi-Fi signals could potentially replace traditional RGB cameras by overcoming obstacles such as poor lighting conditions that camera lenses often face.
The majority of households in developed countries have Wi-Fi at home, making this new technology useful for monitoring the health of the elderly or identifying suspicious behavior. The potential applications of this technology are vast, ranging from assisting law enforcement in raiding buildings to helping firefighters locate people in distress during a fire or in rescue operations.
