Spanish researchers have developed a process to distinguish the original CD copies with a single laser beam.
The experiment conducted by academics Spanish just to be published in the distinguished American Journal of Physics. Members of the optical research department at the University of Granada have discovered a technique to distinguish an original CD a copy. The process has been patented. And could well be integrated into the next player or video game consoles can play movies or music.
To distinguish an original from a fake, scholars are based on differences in the diffraction of light from a laser beam depending on the CD - burned or pressed - (see images below).
Masters product number in the industry obtained by pressing. "[...] The information is stored in the hollow and full that are followed in a groove. The 0 and 1 of binary data are represented in the form of a code: the passage of a hollow full or full to a low indicates 1, while the lack of change means 0 " .
After CDs and DVDs, Blu-ray
The information stored on CD-R (recordable) are obtained by burning some points on the surface of the disc in order to modify the optical properties. This helps to distinguish 0 of 1.
The light projected onto the two types of surfaces (hard pressed and burned disc) did not think the same way. A laser placed at 1 meter of an original CD returns a luminous halo concentric (see picture below), while on a copy, light rays produced two parallel horizontal.
This allows researchers to distinguish the original (pressed) copies (engraved). The experiment was repeated on a hundred CDs references and different brands with the same results, demonstrating the reliability of the method.
The authors of this experience hope that "this technique was tested on DVD [...] may be developed for the detection of pirated discs edge as the
Blu-ray."
The surface of a CD original (factory pressed).
The surface of a copy.
The diffraction of light differs depending on the type of support: On CD (left) or CD pressed (right).
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