Posted on :
14 Jun 2010 11:55 am
Seeing Through Walls
Engineers Develop Technology To See Through Walls
Computer scientists and engineers have developed a new technology for the purpose of seeing through walls. The new technological gadget boasts visual penetration through wood, plaster, brick and reinforced concrete. The device uses sound waves at a particular frequency and a series of algorithms in the computer software to capture images through a wall or door and create 3D images. The military and law enforcement agencies hope to incorporate the device into their projects.
X-ray vision is no longer just for sci-fi movies and superheroes. Now, superhuman powers are closer to real life than you might think. Engineers have developed a new device, called the Xaver that can see straight through walls.
"It’s designed to find people through walls and tell you where they are and how many there are," says engineer Robert Judd. The device can see through plaster, brick, even reinforced concrete. It quickly identifies who or what is in a room and what’s happening behind the walls. The device sends out radio waves through a wall or door. The waves then bounce off objects in a room and bounce back to the device which creates an image of objects in a room -- moving flashes of light represent people or furniture in a room.
"It’s not like opening a curtain and looking through a window, it’s shadows, it’s reflections that look like a cloud for instance."
The military and law enforcement agencies have orders in for the new technology. And seeing what’s behind closed doors could help rescue teams save lives.
"A fireman doesn’t have a lot of time ý he can go in and not waste time searching parts of the building where no one is, or he can go immediately to someone in a room where’s he’s found a life," says aerospace engineer John Reingruber.
And believe it or not, the wireless signals the technology emits are less energy than a standard cell phone.
BACKGROUND: New technology that will be used by law enforcement and the military can look through walls. It is available now, and is being tested by a handful of police departments, before it could move into widespread use.
HOW IT WORKS: The Xaver800 technology provides ’Through the Wall’ vision, allowing the user to rapidly and reliably observe one or more people in a room and monitor their movements, while positioned outside the room’s walls. The system uses sound waves at a particular frequency -- ultra-wide radio waves, which pass through wood and concrete -- to capture images, much like ultrasound imaging captures the image of a fetus through the mother’s skin. Sensors detect the reflected waves. That mechanical motion is translated into electrical signals. Then the computer software algorithms process the signals and create a 3-D image of the people or objects concealed by solid barriers made of cement, plaster, brick, concrete and wood. The system operates on very low power signals; the total energy transmitted is less than that emitted by a standard cellphone.
WHAT ARE RADIO WAVES? Like visible light, radio waves are a part of the electromagnetic spectrum, only with much longer wavelengths. They can be as long as a football field, or as short as a football. This wide range makes them ideal for transmitting information, because different frequencies can be assigned to specific devices. We use radio waves not just in AM, FM, and police and fire department radios, but also in television, radar, cellphones, baby monitors, TV remote controls, and garage door openers, to name just a few. Each type of device has its own frequency range to avoid overlap with others.
SOUND SCIENCE: Sound waves are pressure waves: the result of a vibrating object that creates a disturbance in the surrounding air. The vibrations disturb the molecules that make up the air. The air molecules push closer together as the object moves one way -- an effect known as compression -- and then create a space between themselves and the vibrating object as it moves the other way, called rarefaction. The motion disturbs the neighboring molecules in turn, creating an outward ripple effect, much like a stone cast in a quiet pond will cause waves to ripple outward from the spot where the stone hit. So sound waves travel in repeating patterns of compressions and rarefactions. The distance between compressions determines the wavelength. Objects that vibrate very quickly create short wavelengths because there is very little space between the compressions, creating a high-pitched sound. Objects that vibrate very slowly create long wavelengths because the compressions are spaced further apart. This creates a low-pitched sound. Frequency measures how many crests, or compressions, occur within one second. A sound wave’s amplitude, or range of movement, determines its volume.