Jump forward a decade, and researchers at Germany’s Technical University of Munich have come up with a similar method of creating a holographic map of the inside of buildings using the microwave radiation of Wi-Fi signals as they bounce off people and objects.
“Our work uses the stray radiation from devices like routers or phones to generate a three-dimensional picture of the surroundings,” Philipp Holl, an undergraduate student who worked on the project, told Digital Trends. “Basically, each device acts as a light bulb of different color and lights up its environment. Due to the longer wavelength of microwave radiation compared to the visible spectrum, the Wi-Fi signals can pass through many materials, making walls appear transparent, almost like glass.”
While there have been previous projects that used stray Wi-Fi radiation for motion detection, or even coarse 2D imaging, Holl said that the team at the Technical University of Munich are the first to use it to obtain a full three-dimensional picture.
“This technique could be used for centimeter-precise indoor tracking of tagged objects or tools in a smart factory,” he continued. “It could also be used to create 3D scans of buildings or structures. Imagine, for example, a drone or a truck carrying an array of antennas to quickly map out a large area. Such scans could be used to improve tracking precision with simpler setups or to find optimal locations for placing transmitting devices like routers to maximize signal coverage.”
A similar setup may also be utilized as a search and rescue tool for finding people buried by avalanches or earthquakes. All that would be needed to find them would be for a trapped person to have their phone switched on.
At present, the team has performed scans of easy-to-see structures, such as the aluminum cross pictured above, as a way of testing this technology. Now, they want to further put it through its paces by creating holographic images of real buildings to find out which materials are easy to see through, and which might cause problems.
In other words, keep watching this space. And we mean that both literally and figuratively.
