Researchers hide data in passport photos

Technology would step up passport security

LONDON, England (Reuters) -- Passport photographs in the future could be more than just a pretty picture if a new computer technique developed by Israeli scientists catches on.

Researchers at Ben-Gurion University have devised a way to hide information such as a fingerprint or a signature in color images which could improve passport security or be used to create invisible product bar codes or designs.

"The documents can be faxed, scanned and reprinted without the hidden data disappearing," New Scientist magazine said on Wednesday.

Joseph Rosen and a team of scientists created an algorithm that converts a fingerprint or signature into a series of numbers which are used to shift the dots that make up a color picture.

"Each dot can be displaced slightly without noticeably altering the final appearance of the image," the magazine said.

Connect the dots

Several images can be concealed in a single picture. Each image and the picture are scanned into a computer which does the work. The hidden images or fingerprints cannot be revealed until the picture is scanned again.

The computer reconstructs the fingerprint by measuring the displacement of the dots in the picture.

The magazine said that if the algorithm is distributed to passport checkpoints the picture can be unscrambled to reveal the fingerprint or signature and checked against the person holding the passport.

The researchers are now working on a hand-held device which could make unscrambling the hidden information easier.

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