Washington, Dec 7 (PTI) Scientists have devised a way tosee through walls without any advance knowledge of thematerial they are made of.
Besides having applications in the realm of security, theapproach could lead to inexpensive devices to helpconstruction workers easily locate conduits, pipes and wires.
"Most technologies that can see through walls use a broadrange of frequencies, which makes them expensive," saidDaniel Marks, associate research professor at Duke Universityin the US.
"They also do not have very good resolution. So whilethey might be fine for seeing a person moving on the otherside of a wall, they are terrible for finding thin conduitsor wires," said Marks.
Current approaches also typically rely on knowing whatmaterial the wall is made out of before trying to see throughit.
This allows the software to predict how the wall willaffect the scanning waves so that it can separate the echoesand distortions from the solid objects being sought.
Since walls are generally flat and uniform in alldirections, they distort waves in a symmetrical fashion.
The new technology described in the journal Optica usesthis symmetry to its advantage.
"We wrote an algorithm that separates the data into parts- one that shows circular symmetry and another that doesnot," said Okan Yurduseven, a postdoctoral researcher atDuke.
"The data that does not have any symmetry is what we aretrying to see," said Yurduseven.
The technique uses only a single frequency to scanbecause it cuts down on the number of interference patternscreated by the wall and single-frequency emitters are muchless expensive than broadband emitters.
Sticking to a narrow range also means that a futuredevice would be easy to avoid interfering with microwavefrequencies dedicated to other technologies, such as Wifi,cellular phone service and Bluetooth, researchers said.
They built a prototype device to see how well it wouldwork.
In their laboratory, the researchers constructed a coupleof different kinds of walls and then placed objects behindthem that a worker might want to find, like studs, electricalconduits, wires and junction boxes.
Looking at the raw data after scanning through gypsumplasterboard, it is difficult to make out anything other thana metal junction box, which is four inches wide and twoinches thick.
However, after analysing the data and removing thesymmetrical patterns, the pictures clear considerably, andeach individual component is easily recognised.
"We envision combining this technique with a machinevision system that someone could move over a wall to see whatis inside," said Marks.
"We think the technology has the price point andsensitivity to make an impact on the market," he said. PTISARSAR.
This is unedited, unformatted feed from the Press Trust of India wire.