Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Holographic analysis of Wi-Fi data generates 3D images of the vicinity

04.05.2017

Scientists at the Technical University of Munich (TUM) have developed a holographic imaging process that depicts the radiation of a Wi-Fi transmitter to generate three-dimensional images of the surrounding environment. Industrial facility operators could use this to track objects as they move through the production hall.

Just like peering through a window, holograms project a seemingly three-dimensional image. While optical holograms require elaborate laser technology, generating holograms with the microwave radiation of a Wi-Fi transmitter requires merely one fixed and one movable antenna, as Dr. Friedenmann Reinhard and Philipp Holl report in the current issue of the renowned scientific journal Physical Review Letters.


A cross made of aluminum foil between the viewer and the WLAN-router can easily be reconstructed from the WLAN-hologram as can be seen in the inserted picture

Image: Friedemann Reinhard/Philipp Holl / TUM

“Using this technology, we can generate a three-dimensional image of the space around the Wi-Fi transmitter, as if our eyes could see microwave radiation,” says Friedemann Reinhard, director of the Emmy Noether Research Group for Quantum Sensors at the Walter Schottky Institute of the TU Munich.

The researchers envision fields of deployment especially in the domain of industry 4.0 – automated industrial facilities, in which localizing parts and devices is often difficult.

Wi-Fi penetrates walls

Processes that allow the localization of microwave radiation, even through walls, or in which changes in a signal pattern signify the presence of a person already exist. The novelty is that an entire space can be imaged via holographic processing of Wi-Fi or cell phone signals.

“Of course, this raises privacy questions. After all, to a certain degree even encrypted signals transmit an image of their surroundings to the outside world,” says the project leader, Friedemann Reinhard. “However, it is rather unlikely that this process will be used for the view into foreign bedrooms in the near future. For that, you would need to go around the building with a large antenna, which would hardly go unnoticed. There are simpler ways available.”

Centimeter-scale precision

Hitherto, generating images from microwave radiation required special-purpose transmitters with large bandwidths. Using holographic data processing, the very small bandwidths of typical household Wi-Fi transmitters operating in the 2.4 and 5 gigahertz bands were sufficient for the researchers. Even Bluetooth and cell phone signals can be used. The wavelengths of these devices correspond to a spatial resolution of a few centimeters.

“Instead of a using a movable antenna, which measures the image point by point, one can use a larger number of antennas to obtain a video-like image frequency,” says Philipp Holl, who executed the experiments. “Future Wi-Fi frequencies, like the proposed 60 gigahertz IEEE 802.11 standard will allow resolutions down to the millimeter range.”

Looking to the future

Well-known optical methods for image processing can also be deployed in Wi-Fi holography: One example is the dark-field methodology used in microscopy, which improves the recognition of weakly diffracting structures. A further process is white-light holography in which the researchers use the remaining small bandwidth of the Wi-Fi transmitter to eliminated noise from scattered radiation.

The concept of treating microwave holograms like optical images allows the microwave image to be combined with camera images. The additional information extracted from the microwave images can be embedded into the camera image of a smart phone, for example to trace a radio tag attached to a lost item.

But the scientists are just at the beginning of the technological development. For example, research on the transparency of specific materials is lacking. This knowledge would facilitate the development of paint or wall paper translucent to microwaves for privacy protection, while transparent materials could be deployed in factory halls to allow parts to be tracked.

The researchers hope that further advancement of the technology may aid in the recovery of victims buried under an avalanche or a collapsed building. While conventional methods only allow point localization of victims, holographic signal processing could provide a spatial representation of destroyed structures, allowing first responders to navigate around heavy objects and use cavities in the rubble to systematically elucidate the easiest approach to quickly reach victims.

The research was funded by the Emmy Noether Program of the German Research Foundation (DFB) and the TUM Junior Fellow Fund.

Publication:

Philipp M. Holl and Friedemann Reinhard: Holography of Wi-fi Radiation.
Physical Review Letters, 05.04.2017 – DOI: 10.1103/PhysRevLett.118.183901
https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.118.183901

Contact:

Dr. Friedemann Reinhard
Technical University of Munich
Walter Schottky Institute, E24
Am Coulombwall 4, 85748 Garching, Germany
Tel.: +49 89 289 12777
e-mail: friedemann.reinhard@wsi.tum.de
Web: http://go.tum.de/354019

Weitere Informationen:

https://www.tum.de/en/about-tum/news/press-releases/detail/article/33897/ Link to the press release
http://www.sciencemag.org/news/2017/04/stray-wi-fi-signals-could-let-spies-see-i... „Science“ news post about the publication
https://mediatum.ub.tum.de/1359938 Images

Dr. Ulrich Marsch | Technische Universität München

More articles from Information Technology:

nachricht Controlling robots with brainwaves and hand gestures
20.06.2018 | Massachusetts Institute of Technology, CSAIL

nachricht Innovative autonomous system for identifying schools of fish
20.06.2018 | IMDEA Networks Institute

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>