MIT researchers are developing a camera system that can read closed books.
A prototype was recently able to correctly identify letters on the top nine sheets of stacked papers.
Dreamed up by MIT Media Lab research scientist Barmak Heshmat, the technique uses terahertz radiation -- the band of electromagnetic radiation between microwaves and infrared light -- to distinguish between ink and blank paper, and gauge distance to individual pages.
"So much work has gone into terahertz technology to get the sources and detectors working, with big promises for imagining new and exciting things," Laura Waller, associate professor of electrical engineering and computer science at the University of California at Berkeley, said in a statement.
"This work is one of the first to use these new tools along with advances in computational imaging to get at pictures of things we could never see with optical technologies" she continued. "Now we can judge a book through its cover!"
The technology could eventually be used to scan antique tomes too delicate for human touch, or any materials organized in thin layers, like coatings on machine parts or pharmaceuticals.
"The Metropolitan Museum in New York showed a lot of interest in this, because they want to, for example, look into some antique books that they don't even want to touch," Heshmat said.
In partnership with the Georgia Institute of Technology, MIT developed the algorithms that acquire images from individual sheets in a stack of papers. Georgia Tech scientists, meanwhile, built the other key ingredient: a method for interpreting distorted or incomplete images as individual letters.
"It's actually kind of scary," Heshmat said of GT's letter-interpretation algorithm. "A lot of websites have those [captchas] to make sure you're not a robot, and this algorithm can get through a lot of them."