Wi-Fi Radiation Passes Through Many Materials: Allows German Researchers To Create 3D Holographic Map Of House

Microwave radiation has a longer wavelength when compared to the visible spectrum, resulting in Wi-Fi radiation signals passing through a lot of materials. In the case of walls, it appears transparent similar to glass. Using that principle, researchers at the Technological University of Munich created a holographic map of a building’s interior by using microwave radiation of Wi-Fi signals when it bounces off objects and people.

Philipp Holl, an undergraduate student of the university, explains that each device acts like a light bulb of a different color and lights up its environment. By using the stray Wi-Fi radiation from gadgets such as phones or routers, the group generated a three-dimensional picture of the surroundings, Holl says, according to Digital Trends.

Holl adds that their team is the first to use Wi-Fi radiation to obtain a full 3D picture. There were past projects that used the stray Wi-Fi radiation for motion detection or coarse 2D imaging. He says the technique has many uses.

Tapping stray Wi-Fi radiation could be used for search and rescue to look for people buried by tremors or avalanches. In a smart factory, it could be utilized for centimeter-precise indoor tracking of tagged tools or objects. The scans could be used to have better precision tracking with simpler setups.

Ars Technica points out that stray Wi-Fi radiation is better that laser light in creating holograms because lasers are bad at seeing through walls. In holography, light is scattered from an object which encodes the 3D structure in the recording process. Besides capturing a fraction of the scattered light, holography records how bright the light is.

Elaborate laser technology is needed for optical holograms, but by using stray Wi-Fi radiation, it would only need a fixed and a movable antenna, Dr. Friedmann Reinhard, also from the university, says. He and Holl discuss their findings in the current issue of Physical Review Letters, a scientific journal, Science Daily reports.