| 摘要 |
A stealth mode technique records information onto the sound track of a camcorder without the knowledge of the user. Infrasound is continuously generated by an array of audio sources placed in a geographical position that potentially encompasses the location of the recording device. A database stores the known characteristics of all audio sources. Once the recorded media is released to the public, a post analysis using a processing unit can decompose the recording back into a set of reconstructed audio sounds. An analysis can be performed to determine which audio sounds match the reconstructed audio sounds so that an estimate of the set of parameters associated with the sound track can be obtained. The set of parameters includes the geographical location and local time of the recording. The geographic location provides the opportunity to capture the terrorists and free the hostages.
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