| US 7,580,832 B2 | ||
| Apparatus and method for robust classification of audio signals, and method for establishing and operating an audio-signal database, as well as computer program | ||
| Eric Allamanche, Nuremberg (Germany); Juergen Herre, Buckenhof (Germany); Oliver Hellmuth, Erlangen (Germany); Thorsten Kastner, Stockheim/Reitsch (Germany); and Markus Cremer, Ilmenau (Germany) | ||
| Assigned to M2ANY GmbH, Garching (Germany) | ||
| Filed on Aug. 31, 2004, as Appl. No. 10/931,635. | ||
| Claims priority of application No. 10 2004 036 154 (DE), filed on Jul. 26, 2004. | ||
| Prior Publication US 2006/0020958 A1, Jan. 26, 2006 | ||
| Int. Cl. G10L 19/02 (2006.01); H03M 1/18 (2006.01) | ||
| U.S. Cl. 704—205 [704/230; 704/500; 341/200; 375/240.03; 375/243] | 32 Claims |
| 22. A method for producing a fingerprint signal from an audio signal, comprising:
calculating energy values for frequency bands of segments of the audio signal which are successive in time, an energy value
for a frequency band depending on an energy of the audio signal in the frequency band, so as to obtain a sequence of vectors
of energy values from the audio signal, a vector component being an energy value in a frequency band;
scaling the energy values to obtain a sequence of scaled vectors wherein scaling comprises taking the logarithm of the energy
values; and
suppressing, downstream with respect to taking the logarithm, a steady component, using a high-pass filtering operation;
temporally low-pass filtering the sequence of scaled vectors to obtain a filtered sequence which represents the fingerprint
signal, or from which the fingerprint signal may be derived; and
quantizing the filtered sequence or a signal based thereon so as to derive the fingerprint signal from the filtered sequence
or from the signal based thereon, wherein a width of a quantization level for a high energy value is larger than a width of
a quantization level for a small energy value.
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