| 摘要 |
PROBLEM TO BE SOLVED: To prevent it that even required sound is reduced, on reducing noise in an acoustic device. SOLUTION: A noise detection section 302 detects a noise component signal from surrounding sound detected by a sound collecting microphone 301. The noise component signal is converted to an opposite phase signal in an opposite phase generation section 304, and mixed with an acoustic signal from the acoustic device itself in a mixing section 305, and radiated to space by a speaker 307. Noise is reduced by the noise component signal whose phase is inverted. In an acoustic pattern recognition section 101, it is determined whether there is an acoustic pattern stored in the acoustic pattern storing section 100 beforehand, as outside of an object of noise reduction. If there is, the corresponding acoustic signal component is made outside of a noise control object by subtracting the corresponding acoustic pattern from the noise signal, and thereby, the required sound is not suppressed. COPYRIGHT: (C)2008,JPO&INPIT
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