| 摘要 |
PROBLEM TO BE SOLVED: To provide a sound collection area control method and a voice input device which have improved separation accuracy between objective sound and noise. SOLUTION: A first space sound pressure gradient component is calculated by applying a space differential function based on a distance between a reference position O and an objective sound source, to a sound pressure signal at the reference position O based on sound pressure signals which are output from a pair of microphone M1 and M2, respectively. A second space sound pressure gradient component in which difference between the respective sound pressure signals of the microphones M1 and M2 is divided by a distance of X-axis direction component, is calculated, and a component of X-axis direction of the first space sound pressure gradient component is calculated. On the basis of difference between the component of X-axis direction of the first space sound pressure gradient component and the second space sound pressure gradient component, a space sound pressure gradient component of noise is estimated. A real time function is derived by applying an inverse function of the space differential function, to a result obtained by removing the space sound pressure gradient component of the noise from the first space sound pressure gradient component or the second space sound pressure gradient component, to extract the real time function as the objective sound. COPYRIGHT: (C)2011,JPO&INPIT
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