Sound pickup device and sound pickup method
A sound pickup method includes splitting a sound pickup signal of a microphone of which sound pickup in a predetermined range is blocked by an acoustic obstacle, into a plurality of sound pickup signals and subjecting at least one sound pickup signal among the plurality of sound pickup signals to band limitation processing, and comparing characteristic amounts of the plurality of sound pickup signals including the sound pickup signal after being subjected to the band limitation processing and controlling a gain of the microphone in accordance with a result of comparing the characteristic amounts.
1. A sound pickup device comprising:
a microphone;
an acoustic obstacle that blocks sound pickup in a predetermined direction range with respect to the microphone;
a signal processor that splits a sound pickup signal of the microphone into a first sound pickup signal and a second sound pickup signal, and outputs a first output signal and a second output signal, wherein the signal processor:
filters the first sound pickup signal to limit a low frequency range of the first sound pickup signal to output the first output signal; and
applies all-band pass processing to the second sound pickup signal to output the second output signal; and
a gain controller that compares between a characteristic amount of the first output signal and a characteristic amount of the second output signal, and controls a gain of the sound pickup signal from the microphone in accordance with a result of the comparing.
2. The sound pickup device according to claim 1 , wherein the characteristic amount of the first output signal and the characteristic amount of the second output signal are changed by the acoustic obstacle when each of the first sound pickup signal and the second sound pickup signal includes sound of a sound source not included in the predetermined direction range.
3. The sound pickup device according to claim 1 , wherein the characteristic amount of the first output signal and the characteristic amount of the second output signal include a signal level.
4. The sound pickup device according to claim 1 , wherein the characteristic amount of the first output signal and the characteristic amount of the second output signal include variance of rise time in a different frequency.
5. The sound pickup device according to claim 1 , wherein the gain controller reduces an output level with respect to an input level, when a difference or a ratio between the characteristic amount of the first sound output signal and the characteristic amount of the second output signal is increased to more than or equal to a predetermined value.
6. The sound pickup device according to claim 1 , wherein the gain controller changes an output level with respect to an input level in accordance with a change in a difference or a ratio between the characteristic amount of the first output signal and the characteristic amount of the second output signal.
7. The sound pickup device according to claim 1 , wherein the acoustic obstacle comprises a housing with a cylindrical shape.
8. The sound pickup device according to claim 1 , wherein the acoustic obstacle comprises a housing with a rectangular parallelepiped shape.
9. The sound pickup device according to claim 1 , wherein the predetermined direction range is a predetermined angle range with respect to a horizontal direction of an installation surface on which the sound pickup device is disposed.
10. The sound pickup device according to claim 9 , wherein the predetermined direction range is an angle range of 16 degrees or less with respect to the horizontal direction.
11. The sound pickup device according to claim 1 , further comprising a sound-absorbing material disposed near the acoustic obstacle.
12. A sound pickup method comprising:
processing a sound pickup signal of a microphone of which sound pickup in a predetermined direction range is blocked by an acoustic obstacle, by splitting the sound pickup signal into a first sound pickup signal and a second sound pickup signal, and outputting a first output signal and a second output signal, wherein the processing of the sound pickup signal:
filters the first sound pickup signal to limit a low frequency range of the first sound pickup signal to output the first output signal; and
applies all-band pass processing to the second sound pickup signal to output the second output signal; and
comparing between a characteristic amount of the first output signal and a characteristic amount of the second output signal, and controlling a gain of the sound pickup signal from the microphone in accordance with a result of the comparing.
13. The sound pickup method according to claim 12 , wherein the characteristic amount of the first output signal and the characteristic amount of the second output signal are changed by the acoustic obstacle when each of the first sound pickup signal and the second pickup signal includes sound of a sound source not included in the predetermined direction range.
14. The sound pickup method according to claim 12 , wherein the characteristic amount of the first output signal and the characteristic amount of the second output signal include a signal level.
15. The sound pickup method according to claim 12 , wherein the characteristic amount of the first output signal and the characteristic amount of the second output signal include variance of rise time in a different frequency.
16. The sound pickup method according to claim 12 , wherein the predetermined direction range is a predetermined angle range with respect to a horizontal direction of an installation surface on which a sound pickup device is disposed.