Technology Detects Audio Tape Tampering

Scientists at the National Institute of Standards and Technology have developed a real-time magnetic imaging system that can detect whether an audiotape has been tampered with quicker and more accurately than currently possible.

The technology revolves around 64 customized magnetic sensors augmented to an ordinary cassette player, all linked to a computer programmed to convert magnetic data into displayable graphics.

The sensors detect and map magnetic fields on tapes during playing. Original cassettes produce non-interrupted, predictable patterns while erasure and overdubbing produce smudges in the image.

Copies can be detected because they lack the original markings specific to various types of tape players.
Abstracted by the National Law Enforcement and Corrections Technology Center(NLECTC) from the United Press International (10/27/04) .