Inspired by DNA testing techniques, researchers have developed a way of identifying pirated movies.
Dr Alex Bronstein of Tel Aviv University says he has created a unique identifier for video. His system uses an invisible set of grids applied over the film, corrsponding to different elements of the image in each frame. This effectively turns the footage into a series of numbers comparable to a DNA fingerprint.
The tool can then scan the content of websites where pirated films may be present, pinpointing subsequent mutations of the original.
When scenes are altered, colors changed, or a film is bootlegged using a camera at the movie theatre, the film can be tracked and traced on the internet, explains Dr Bronstein.
"If a DNA test can identify and catch criminals, we thought that a similar code might be applicable to video. If the code were copied and changed, we'd catch it," says Bronstein.
The technique works by identifying features of the film that remain basically unchanged by typical color and resolution manipulations, or
by geometric transformations. It's effective even with border changes, says Bronstein, or when commercials are added or scenes edited out.
The researchers have set their sights on popular video-sharing web sites like YouTube. YouTube, they point out, automates the detection of copyright infringement to some degree, but only works when the video hasn't been altered.
Bronstein says his method could save production companies thousands of man-hours by detecting the presence of pirated videos even when
they've been altered.