Audio signal processing apparatus, audio signal processing method, and audio signal processing program

• US 20070189551A1
• Filed: 01/25/2007
• Published: 08/16/2007
• Est. Priority Date: 01/26/2006
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Kimijima, Tadaaki
• Granted Patent: US 8,213,648 B2
• Time in Patent Office: Days
• US Class Current: 381/97
• CPC Class Codes: H04S 1/002 Non-adaptive circuits, e.g. manually adjustable or static, for enhancing the sound image or the spatial distribution control circuits for electronic adaptation of the sound field H04S7/30
• CPC Class Codes: H04S 2400/11 Positioning of individual sound objects, e.g. moving airplane, within a sound field H04S2420/13 takes precedence
• CPC Class Codes: H04S 5/005 of the pseudo five- or more-channel type, e.g. virtual surround
• CPC Class Codes: H04S 7/302 Electronic adaptation of stereophonic sound system to listener position or orientation H04S7/301 takes precedence

Abstract

An audio signal processing apparatus includes: a division section that divides at least two or more channel audio signals into components in a plurality of frequency bands; a phase difference calculation section that calculates a phase difference between the two or more channel audio signals at each the frequency band; a level ratio calculation section that calculates a level ratio between the two or more channel audio signals at each the frequency band; a sound image localization estimation section that estimates, based on the level ratio or the phase difference, sound image localization at each the frequency band; and a control section that controls the estimated sound image localization at each the frequency band by adjusting the level ratio or the phase difference.

Claims

1. An audio signal processing apparatus comprising:

division means for dividing at least two or more channel audio signals into components in a plurality of frequency bands;

phase difference calculation means for calculating a phase difference between said two or more channel audio signals at each said frequency band;

level ratio calculation means for calculating a level ratio between said two or more channel audio signals at each said frequency band;

sound image localization estimation means for estimating, based on said level ratio or said phase difference, sound image localization at each said frequency band; and

control means for controlling said estimated sound image localization at each said frequency band by adjusting said level ratio or said phase difference.

2. The audio signal processing apparatus according to claim 1, further comprising

zoom means for evenly enlarging or narrowing, by said control means, the sound image localization at each said frequency band.

3. The audio signal processing apparatus according to claim 1, further comprising

zoom means for unevenly enlarging or narrowing, by said control means, the sound image localization at each said frequency band.

4. The audio signal processing apparatus according to claim 3, wherein

said zoom means places each sound image localization of each sound image at each said frequency band at a predetermined angle with respect to a listener.

5. The audio signal processing apparatus according to claim 3, wherein

said zoom means enlarges a predetermined central area of each sound image localization at each said frequency band.

6. The audio signal processing apparatus according to claim 3, wherein

said zoom means narrows a predetermined central area of each sound image localization at each said frequency band.

7. The audio signal processing apparatus according to claim 1, wherein

said control means adjusts, in accordance with an operation of changing a zoom ratio of a video image being in synchronization with said audio signal, said level ratio or said phase difference.

8. The audio signal processing apparatus according to claim 1, wherein

said control means adjusts, in accordance with a relative position of a certain audio source image with respect to the center of a screen, said level ratio or said phase difference, said certain audio source image existing in a video image being in synchronization with said audio signal.

9. The audio signal processing apparatus according to claim 1, further including

multichannel conversion means for adjusting, using a plurality of gain values, different gains at each said frequency band to convert said two or more channel audio signals into multichannel audio signals whose number of channels is more than that of said two or more channel audio signals, wherein

said control means adjusts said level ratio or said phase difference of said multichannel audio signals.

10. An audio signal processing method comprising:

a division step of dividing at least two or more channel audio signals into components in a plurality of frequency bands;

a phase difference calculation step of calculating a phase difference between said two or more channel audio signals at each said frequency band;

a level ratio calculation step of calculating a level ratio between said two or more channel audio signals at each said frequency band;

a sound image localization estimation step of estimating, based on said level ratio or said phase difference, sound image localization at each said frequency band; and

a control step of controlling said estimated sound image localization at each said frequency band by adjusting said level ratio or said phase difference.

11. An audio signal processing program for causing an audio signal processing apparatus to execute:

a division step of dividing at least two or more channel audio signals into components in a plurality of frequency bands;

a phase difference calculation step of calculating a phase difference between said two or more channel audio signals at each said frequency band;

a level ratio calculation step of calculating a level ratio between said two or more channel audio signals at each said frequency band;

a sound image localization estimation step of estimating, based on said level ratio or said phase difference, sound image localization at each said frequency band; and

a control step of controlling said estimated sound image localization at each said frequency band by adjusting said level ratio or said phase difference.

12. An audio signal processing apparatus comprising:

a division section that divides at least two or more channel audio signals into components in a plurality of frequency bands;

a phase difference calculation section that calculates a phase difference between said two or more channel audio signals at each said frequency band;

a level ratio calculation section that calculates a level ratio between said two or more channel audio signals at each said frequency band;

a sound image localization estimation section that estimates, based on said level ratio or said phase difference, sound image localization at each said frequency band; and

a control section that controls said estimated sound image localization at each said frequency band by adjusting said level ratio or said phase difference.