An astonishing new technology has been developed by scientists, including one of Indian origin that can read pages of a closed book, says a study published in the journal Nature Communications.
Researchers from Massachusetts Institute of Technology (MIT), including Ramesh Raskar, tested the technology on a sample of papers, each with one letter printed on it. The system was able to correctly identify the letters on the top nine sheets.
About the technology:
- The researchers from US's MIT and Georgia Institute of Technology (Georgia Tech) developed the algorithm that acquires images from individual sheets in stacks of paper, and interprets the often distorted or incomplete images as individual letters
- Terahertz radiation, the band of electromagnetic radiation between microwaves and infrared light is used by the system. It has several advantages over other types of waves that can penetrate surfaces, such as X-rays or sound waves
- Its frequency profiles can separate between ink and blank paper and has much better depth resolution than ultrasound
- The system develops the fact that tiny air pockets are trapped between the pages of a book about 20 micrometres deep
- The gap in refractive index between the air and paper means that the boundary between the two will reflect terahertz radiation back to a detector
- The new system consists of a standard terahertz camera that emits ultra-short bursts of radiation and the camera's built-in sensor detects their reflections
- From the reflection's time of arrival, the algorithm can measure the distance to the individual pages of the book
- Currently, the algorithm can correctly deduce the distance from the camera to the top 20 pages in a stack, but past a depth of nine pages, the energy of the reflected signal is so low that the differences between frequency signatures are swamped by noise
- "Terahertz imaging is still a relatively young technology, and researchers are constantly working to improve both the accuracy of detectors and the power of the radiation sources so that deeper penetration could be made possible," researchers said
View of the Scientist:
A research scientist at MIT, Barmak Heshmat said, "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."
The system could examine any materials organised in thin layers, such as coatings on machine parts or pharmaceuticals, he said
"A lot of websites have these letter certifications (captchas) to make sure you are not a robot, and this algorithm can get through a lot of them," said Heshmat.