Scientists from MIT now can identify letters printed on stacks of paper up to nine sheets thick. This could happen due to a novel technology that uses x-ray vision technology. Through this, scientists are now able to read closed books. This innovation causes office machines that can scan reams of paper at once. It could also help researchers to scan ancient books that are too fragile to open.
The device uses terahertz radiation. Terahertz radiation is the band of electromagnetic radiation between microwaves and infrared light. For example, terahertz rays can differentiate between the ink and blank paper in a way that X-rays cannot. They can also scan across depths to yield higher-resolution images than ultrasound can accomplish.
Although, This new system depends on how different chemicals absorb different frequencies of terahertz radiation to varying degrees. In such way, it can tell the difference between papers that has ink on it versus paper that does not.
Scientists used a terahertz camera to scan a stack of card-size sheets of paper. Each sheet was 300-micron-thick in size. Each had a single letter about 0.3 inches wide written on only one side in pencil or ink.
So scientists develop an algorithm interpret the frequently distorted or incomplete images from the camera as individual letters.
Scientists said, “In experiments, the prototype correctly read the nine letters T, H, Z, L, A, B, C, C and G from the front to the back of a nine-page stack.”
Barmak Heshmat, an electrical engineer at MIT, said, “The system we used was not necessarily a top-of-the-line system. If the system was improved further, we will have a chance of reading even deeper.”
“The Metropolitan Museum in New York showed huge interest in this. Because they want to look into some antique books that they don’t even want to touch,” he added.
This new system feats the fact that air and paper each bend light to a different degree. Additionally, those pages of a book trap air pocket between them. Theses pockets are only about 20 microns deep. That means they have an only one-fifth size of the average width of a human hair.
Scientists said, “this is enough for the device to differentiate the signals from different pages of a book.”
Heshmat said, “It could be used in future scanners that scan through large amounts of documents without having to mechanically separate the pages. It could be useful for libraries, banks, and others. Such a future scanner wouldn’t use terahertz waves, but perhaps infrared light.”
“It might even be possible for spies to use this technology to peer through envelopes. Still, it could be possible to use ink that is not visible in the frequency ranges used. Other potential industrial applications may include analyzing any materials organized in thin layers. For example, layers of paint or coatings on machine parts or pharmaceuticals,” he continued.