Sound-field correction device, sound-field correction method, and sound-field correction program

1. A sound-field correction device, comprising:

a target calculating unit configured to calculate, based on a predetermined sound signal, a target amplitude characteristic targeted for sound-field correction by a parametric equalizer and a plurality of auxiliary target amplitude characteristics having amplitude characteristics approximately equal to or gentler than the target amplitude characteristic;

a correction amplitude characteristic calculating unit configured to calculate a correction amplitude characteristic for correcting sound-field based on the calculated target amplitude characteristic and the calculated plurality of auxiliary target amplitude characteristics by

selecting a frequency band for respective auxiliary target amplitude characteristics based on an amplitude characteristic of the respective auxiliary target amplitude characteristic,

calculating a correction parameter for the respective auxiliary target amplitude characteristics based on an amplitude characteristic of the respective auxiliary target amplitude characteristics within the selected frequency band, and

selecting a correction parameter closest to the target amplitude characteristic from among the calculated correction parameters for the respective auxiliary target amplitude characteristics; and

a setting unit configured to set the parametric equalizer based on the calculated correction amplitude characteristic.

2. The sound-field correction device according to claim 1 , wherein:

the target calculating unit is configured to calculate an amplitude characteristic of the sound signal based on the sound signal, to subject the calculated amplitude characteristic to an averaging process in a first resolution, and to calculate the target amplitude characteristic based on the amplitude characteristic subjected to the averaging process; and

the target calculating unit is configured to calculate the amplitude characteristic of the sound signal based on the sound signal, to subject the calculated amplitude characteristic to an averaging process in a resolution approximately equal to the first resolution or in a plurality of types of resolutions which are rougher than the first resolution and are different from each other, and to calculate the plurality of auxiliary target amplitude characteristics based on the amplitude characteristics subjected to the averaging process in the plurality of types of resolutions different from each other.

3. The sound-field correction device according to claim 1 , wherein:

the correction amplitude characteristic calculating unit is configured to divide each of the auxiliary target amplitude characteristics into a plurality of groups in a frequency domain based on a predetermined condition, to calculate priority of each of the divided groups, and to select a group having highest calculated priority for each of the auxiliary target amplitude characteristics;

the correction amplitude characteristic calculating unit is configured to calculate a parameter of the parametric equalizer of a correction candidate for each of the auxiliary target amplitude characteristics based on the selected group in the frequency domain, and to obtain the parameter of the parametric equalizer of a correction target based on the calculated parameter of each of the auxiliary target amplitude characteristics; and

the setting unit is configured to set the parametric equalizer based on the parameter of the parametric equalizer of the correction target.

4. The sound-field correction device according to claim 3 ,

wherein the correction amplitude characteristic calculating unit is configured to calculate an amplitude characteristic of the correction candidate for each of the auxiliary target amplitude characteristics based on the parameter of the parametric equalizer of the correction candidate, and to obtain, as the parameter of the parametric equalizer of the correction target, the parameter of one of amplitude characteristics of the calculated respective correction candidates having a smallest difference with respect to the target amplitude characteristic.

5. The sound-field correction device according to claim 3 , wherein:

when the parameter of the parametric equalizer of the correction target is obtained, the correction amplitude characteristic calculating unit calculates, as a new target amplitude characteristic, a difference between the target amplitude characteristic and one of the amplitude characteristics of the correction candidates calculated for the respective auxiliary target amplitude characteristics having a smallest difference with respect to the target amplitude characteristic, and calculates, as a new plurality of auxiliary target amplitude characteristics, differences between the amplitude characteristic of the correction target and the respective auxiliary target amplitude characteristics; and

when a number of obtained parametric equalizers of the correction target does not reach a predetermined number, the correction amplitude characteristic calculating unit further obtains the parameter of the parametric equalizer of the correction target based on the new target amplitude characteristic and the new plurality of auxiliary target amplitude characteristic.

6. The sound-field correction device according to claim 3 , wherein the parameter includes a center frequency, a gain and a frequency band width.

7. A sound-field correction method, comprising:

calculating, based on a predetermined sound signal, a target amplitude characteristic targeted for sound-field correction by a parametric equalizer and a plurality of auxiliary target amplitude characteristics having amplitude characteristics approximately equal to or gentler than the target amplitude characteristic;

calculating a correction amplitude characteristic for correcting sound-field based on the calculated target amplitude characteristic and the calculated plurality of auxiliary target amplitude characteristics by

selecting a frequency band for respective auxiliary target amplitude characteristics based on an amplitude characteristic of the respective auxiliary target amplitude characteristics;

calculating a correction parameter for the respective auxiliary target amplitude characteristics based on an amplitude characteristic of the respective auxiliary target amplitude characteristics within the selected frequency band, and

selecting a correction parameter closest to the target amplitude characteristic from among the calculated correction parameters for the respective auxiliary target amplitude characteristics; and

setting the parametric equalizer based on the calculated correction amplitude characteristic.

8. The sound-field correction method according to claim 7 , wherein the calculating the target amplitude characteristic comprises:

calculating an amplitude characteristic of the sound signal based on the sound signal, subjecting the calculated amplitude characteristic to an averaging process in a first resolution, and calculating the target amplitude characteristic based on the amplitude characteristic subjected to the averaging process; and

calculating the amplitude characteristic of the sound signal based on the sound signal, subjecting the calculated amplitude characteristic to an averaging process in a resolution approximately equal to the first resolution or in a plurality of types of resolutions which are rougher than the first resolution and are different from each other, and calculating the plurality of auxiliary target amplitude characteristics based on the amplitude characteristics subjected to the averaging process in the plurality of types of resolutions different from each other.

9. The sound-field correction method according to claim 7 , wherein the calculating the correction amplitude characteristic comprises:

dividing each of the auxiliary target amplitude characteristics into a plurality of groups in a frequency domain based on a predetermined condition, calculating priority of each of the divided groups, and selecting a group having highest calculated priority for each of the auxiliary target amplitude characteristics; and

calculating a parameter of the parametric equalizer of a correction candidate for each of the auxiliary target amplitude characteristics based on the selected group in the frequency domain, and obtaining the parameter of the parametric equalizer of a correction target based on the calculated parameter of each of the auxiliary target amplitude characteristics, and

wherein the setting the parametric equalizer comprises setting the parametric equalizer based on the parameter of the parametric equalizer of the correction target.

10. The sound-field correction device according to claim 9 ,

wherein the calculating the correction amplitude characteristic comprises calculating an amplitude characteristic of the correction candidate for each of the auxiliary target amplitude characteristics based on the parameter of the parametric equalizer of the correction candidate, and obtaining, as the parameter of the parametric equalizer of the correction target, the parameter of one of amplitude characteristics of the calculated respective correction candidates having a smallest difference with respect to the target amplitude characteristic.

11. The sound-field correction device according to claim 9 , wherein the calculating the correction amplitude characteristic comprises:

when the parameter of the parametric equalizer of the correction target is obtained, calculating, as a new target amplitude characteristic, a difference between the target amplitude characteristic and one of the amplitude characteristics of the correction candidates calculated for the respective auxiliary target amplitude characteristics having a smallest difference with respect to the target amplitude characteristic, and calculating, as a new plurality of auxiliary target amplitude characteristics, differences between the amplitude characteristic of the correction target and the respective auxiliary target amplitude characteristics; and

when a number of obtained parametric equalizers of the correction target does not reach a predetermined number, further obtaining the parameter of the parametric equalizer of the correction target based on the new target amplitude characteristic and the new plurality of auxiliary target amplitude characteristic.

12. The sound-field correction method according to claim 9 , wherein the parameter includes a center frequency, a gain and a frequency band width.

13. A non-transitory computer readable medium having computer readable instruction stored thereon, which, when executed by a processor of a sound-field correction device, configures the processor to perform:

calculating, based on a predetermined sound signal, a target amplitude characteristic targeted for sound-field correction by a parametric equalizer and a plurality of auxiliary target amplitude characteristics having amplitude characteristics approximately equal to or gentler than the target amplitude characteristic;

calculating a correction amplitude characteristic for correcting sound-field based on the calculated target amplitude characteristic and the calculated plurality of auxiliary target amplitude characteristics by

selecting a frequency band for respective auxiliary target amplitude characteristics based on an amplitude characteristic of the respective auxiliary target amplitude characteristics,

calculating a correction parameter for the respective auxiliary target amplitude characteristics based on an amplitude characteristic of the respective auxiliary target amplitude characteristics within the selected frequency band, and

selecting a correction parameter closest to the target amplitude characteristic from among the calculated correction parameters for the respective auxiliary target amplitude characteristics; and

setting the parametric equalizer based on the calculated correction amplitude characteristic.