| 摘要 |
A digital signature generation device (1) for generating signatures from an audio signal (received electrically or acoustically), the device comprising: a signal energy analyser (12) arranged to determine the energy level at each of one or more particular frequencies in a sampled data segment of the audio signal; an event detector (13) arranged to detect the occurrence of a predetermined event in the energy level (peak energy, rate of change of energy) of each of the particular frequency of the sampled data segment; and a signature generator (14) arranged to extract event data identifying a set of predetermined events detected by the event detector, the event data forming a digital signature for the sampled data segment. A device for identifying two signal as matching is also disclosed. The device may be used in TV/RADIO audience measurement systems.
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