SIGNAL PROCESSING DEVICE AND SIGNAL PROCESSING METHOD

• US 20090279709A1
• Filed: 04/29/2009
• Published: 11/12/2009
• Est. Priority Date: 05/08/2008
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: Asada, Kohei, Itabashi, Tetsunori, Ozawa, Noriyuki
• Granted Patent: US 8,107,637 B2
• Time in Patent Office: Days
• US Class Current: 381/71.100
• CPC Class Codes: G10K 11/17825 Error signals
• CPC Class Codes: G10K 11/17833 by using a self-diagnostic function or a malfunction prevention function, e.g. detecting abnormal output levels
• CPC Class Codes: G10K 11/17854 the filter being an adaptive filter
• CPC Class Codes: G10K 11/17873 using a reference signal without an error signal, e.g. pure feedforward
• CPC Class Codes: G10K 11/17875 using an error signal without a reference signal, e.g. pure feedback
• CPC Class Codes: G10K 11/17881 the reference signal being an acoustic signal, e.g. recorded with a microphone
• CPC Class Codes: G10K 11/17885 additionally using a desired external signal, e.g. pass-through audio such as music or speech
• CPC Class Codes: G10K 2210/1081 Earphones, e.g. for telephones, ear protectors or headsets
• CPC Class Codes: G10K 2210/3028 Filtering, e.g. Kalman filters or special analogue or digital filters

Abstract

A signal processing device includes: a filter processing unit configured to execute noise reduction operations by subjecting sound-collected signals from a sound-collecting unit to filtering processing based on preset filter properties and providing with signal properties for noise reduction; a noise-unreduced signal obtaining unit configured to obtain noise-unreduced signals obtained in a state where noise reduction operations by the filter processing unit are stopped; and a filter property selecting unit configured to obtain a difference between the noise-unreduced signals and noise-reduced signals obtained at the time of executing noise reduction operations with preset filter properties set to the filter processing unit as a candidate filter property, thereby obtaining a noise reduction effect indicator regarding the candidate filter property, and selecting filter properties to be set to the filter processing unit based on the noise reduction effect indicator.

Claims

1. A signal processing device comprising:

filter processing means configured to execute noise reduction operations by subjecting sound-collected signals from sound-collecting means to filtering processing based on preset filter properties and providing with signal properties for noise reduction;

noise-unreduced signal obtaining means configured to obtain noise-unreduced signals obtained in a state where noise reduction operations by said filter processing means are stopped; and

filter property selecting means configured to obtain a difference between said noise-unreduced signals and noise-reduced signals obtained at a time of executing noise reduction operations with the preset filter properties set to said filter processing means as a candidate filter property, thereby obtaining a noise reduction effect indicator regarding said candidate filter property, and selecting filter properties to be set to said filter processing means based on said noise reduction effect indicator.

2. The signal processing device according to claim 1, further comprising:

storage means configured to store information of the filter property selected by said filter property selecting means.

3. The signal processing device according to claim 2, further comprising:

setting means configured to set a filter property, corresponding to stored information in said storage means, to said filter processing means.

4. The signal processing device according to claim 3, wherein said filter property selecting means calculate the difference in amplitude component for each predetermined frequency point, as a difference between said noise- unreduced signals and said noise-reduced signals.

5. The signal processing device according to claim 4, wherein said filter property selecting means sequentially perform calculation of the difference in amplitude component for each predetermined frequency point between said noise-unreduced signals and said noise-reduced signals, each time said noise reduction signals regarding one candidate filter property are obtained.

6. The signal processing device according to claim 5, wherein said filter property selecting means calculate the total value of the differences in amplitude component for each predetermined frequency point between said noise- unreduced signals and said noise-reduced signals, as said noise reduction effect indicator, and select a candidate filter property with the greatest total value as the filter property to be set to said filter processing means.

7. The signal processing device according to claim 5, wherein said filter property selecting means calculate the total value of the differences in amplitude component for each predetermined frequency point between said noise-unreduced signals and said noise-reduced signals, as said noise reduction effect indicator, and select a candidate filter property of which the total value satisfies conditions based on a predetermined stipulated value, as the filter property to be set to said filter processing means.

8. The signal processing device according to claim 5, wherein said filter property selecting means take the value of the difference in amplitude component for each predetermined frequency point, calculated regarding said noise-unreduced signals and said noise-reduced signals, as said noise reduction effect indicator, and select a candidate filter property of which the noise reduction effect indicator at each frequency point satisfies conditions based on predetermined stipulated values for each frequency point, as the filter property to be set to said filter processing means.

9. The signal processing device according to claim 5, wherein said filter property selecting means cancel filter property selection operations in the event that at least one value of difference in amplitude component for each predetermined frequency point, calculated regarding said noise-unreduced signals and said noise-reduced signals, does not satisfy a predetermined value set beforehand.

10. The signal processing device according to claim 1, wherein said sound-collecting means are provided on an inner side of a housing unit worn on an ear of a listener;

and wherein said noise-unreduced signal obtaining means obtain sound-collected signals from said sound- collecting means, at the time of noise reduction operations by said filter processing being having been stopped, as said noise-unreduced signals.

11. The signal processing device according to claim 1, further comprising:

input means configured to input other sound-collected signals obtained from other sound-collected means, provided on an outer side of a housing unit worn on an ear of a listener, separate from said sound-collected means provided on the inner side of said housing unit;

wherein said noise-unreduced signal obtaining means obtain input signals from said input means, at the time of noise reduction operations by said filter processing being having been stopped, as said noise-unreduced signals.

12. The signal processing device according to claim 11, further comprising:

adding means configured to add listening audio signals to the noise-reduced signals obtained by said filter processing means;

wherein said input means are used in common for input of said other sound-collected signals from said other sound-collecting means, and input of said listening audio signals.

13. A signal processing method comprising steps of:

obtaining noise-unreduced signals in a state where noise reduction operations by filter processing means, which execute the noise reduction operations by subjecting sound-collected signals from sound-collecting means to filtering processing based on preset filter properties and providing with signal properties for noise reduction, are stopped; and

obtaining a difference between said noise-unreduced signals and noise-reduced signals obtained at a time of executing noise reduction operations with the preset filter properties set to said filter processing means as a candidate filter property, thereby obtaining a noise reduction effect indicator regarding said candidate filter property, and selecting filter properties to be set to said filter processing means based on said noise reduction effect indicator.

14. A signal processing device comprising:

a filter processing unit configured to execute noise reduction operations by subjecting sound-collected signals from a sound-collecting unit to filtering processing based on preset filter properties and providing with signal properties for noise reduction;

a noise-unreduced signal obtaining unit configured to obtain noise-unreduced signals obtained in a state where noise reduction operations by said filter processing unit are stopped; and

a filter property selecting unit configured to obtain a difference between said noise-unreduced signals and noise-reduced signals obtained at a time of executing noise reduction operations with the preset filter properties set to said filter processing unit as a candidate filter property, thereby obtaining a noise reduction effect indicator regarding said candidate filter property, and selecting filter properties to be set to said filter processing unit based on said noise reduction effect indicator.

15. A signal processing method comprising the steps of:

obtaining noise-unreduced signals in a state where noise reduction operations by a filter processing unit, which executes the noise reduction operations by subjecting sound-collected signals from a sound-collecting unit to filtering processing based on preset filter properties and providing with signal properties for noise reduction, are stopped; and

obtaining a difference between said noise-unreduced signals and noise-reduced signals obtained at a time of executing the noise reduction operations with the preset filter properties set to said filter processing unit as a candidate filter property, thereby obtaining a noise reduction effect indicator regarding said candidate filter property, and selecting filter properties to be set to said filter processing unit based on said noise reduction effect indicator.