Signal processing apparatus and signal processing method to reduce external noise
[Object] To provide a signal processing apparatus which can allow a user to listen to sound assumed by a designer while a difference among individuals is taken into account. [Solution] Provided is a signal processing apparatus including: a characteristics difference calculating unit configured to calculate a difference between reproduction target characteristics of a first sound signal and characteristics of a second sound signal obtained by collecting, at a microphone provided inside a headphone, sound output from a driver which outputs the sound based on a third sound signal obtained by performing signal processing on the first sound signal; and a sound signal processing unit configured to select a parameter to be used at the signal processing based on the difference calculated by the characteristics difference calculating unit, and perform signal processing on the first sound signal.
1. A signal processing apparatus, comprising:
a characteristics difference calculating unit configured to calculate a difference between reproduction target characteristics of a first sound signal and characteristics of a second sound signal,
wherein the second sound signal is obtained by collection of, by a microphone inside a headphone, sound output from a driver of the headphone,
wherein the driver outputs the sound based on a third sound signal, and
wherein the third sound signal is obtained by execution of a first signal processing on the first sound signal; and
a sound signal processing unit configured to:
select a first parameter for a first filter configured to adjust sound quality of the first sound signal and a second parameter for a second filter configured to execute noise reduction processing of the second sound signal,
wherein the first parameter and the second parameter are selected based on the difference calculated by the characteristics difference calculating unit, and
wherein the first filter is different from the second filter; and
execute a second signal processing on the first sound signal,
wherein the difference between the reproduction target characteristics of the first sound signal and the characteristics of the second sound signal is based on a difference in physical characteristics of wearers of the headphone.
2. The signal processing apparatus according to claim 1 ,
wherein the sound signal processing unit is further configured to select the first parameter from parameters of the first filter set in advance.
3. The signal processing apparatus according to claim 1 ,
wherein the sound signal processing unit is further configured to select the second parameter from parameters of the second filter set in advance.
4. The signal processing apparatus according to claim 1 ,
wherein the noise reduction processing is feedback type noise reduction processing.
5. The signal processing apparatus according to claim 1 ,
wherein the noise reduction processing is feedforward type noise reduction processing.
6. The signal processing apparatus according to claim 1 ,
wherein the noise reduction processing is combination of feedback type noise reduction processing and feedforward type noise reduction processing.
7. The signal processing apparatus according to claim 1 ,
wherein the characteristics difference calculating unit is further configured to calculate the difference between the reproduction target characteristics and the characteristics of the second sound signal by comparison of frequency characteristics of the first sound signal with frequency characteristics of the second sound signal.
8. The signal processing apparatus according to claim 1 ,
wherein the characteristics difference calculating unit is further configured to calculate the difference between the reproduction target characteristics and the characteristics of the second sound signal at a determined interval.
9. The signal processing apparatus according to claim 1 ,
wherein the characteristics difference calculating unit is further configured to calculate the difference between the reproduction target characteristics and the characteristics of the second sound signal based on a time of detection that the headphone is worn.
10. The signal processing apparatus according to claim 1 ,
wherein the difference between the reproduction target characteristics and the characteristics of the second sound signal is based on variation in a sealing level, and
wherein the sealing level indicates a space between a head of each of the wearers and a housing of the headphone.
11. A signal processing method, comprising:
calculating a difference between reproduction target characteristics of a first sound signal and characteristics of a second sound signal,
wherein the second sound signal is obtained by collecting, by a microphone inside a headphone, sound output from a driver of the headphone,
wherein the driver outputs the sound based on a third sound signal, and
wherein the third sound signal is obtained by a signal processing on the first sound signal; and
selecting a first parameter for a first filter configured to adjust sound quality of the first sound signal and a second parameter for a second filter configured to execute noise reduction processing of the second sound signal,
wherein the first parameter and the second parameter are selected based on the calculated difference,
wherein the first filter is different from the second filter, and
wherein the difference between the reproduction target characteristics of the first sound signal and the characteristics of the second sound signal is based on a difference in physical characteristics of wearers of the headphone.
12. A non-transitory computer-readable storage medium having stored thereon, computer-executable instructions, which when executed by a computer, cause the computer to execute operations, the operations comprising:
calculating a difference between reproduction target characteristics of a first sound signal and characteristics of a second sound signal,
wherein the second sound signal is obtained by collecting, by a microphone inside a headphone, sound output from a driver of the headphone,
wherein the driver outputs the sound based on a third sound signal, and
wherein the third sound signal is obtained by a signal processing on the first sound signal; and
selecting a first parameter for a first filter configured to adjust sound quality of the first sound signal and a second parameter for a second filter configured to execute noise reduction processing of the second sound signal,
wherein the first parameter and the second parameter are selected based on the calculated difference,
wherein the first filter is different from the second filter, and
wherein the difference between the reproduction target characteristics of the first sound signal and the characteristics of the second sound signal is based on a difference in physical characteristics of wearers of the headphone.
13. The signal processing apparatus according to claim 1 , wherein the physical characteristics include at least one of a shape of head, a size of ear or a length of hair of each of the wearers.
14. The signal processing apparatus according to claim 13 , wherein the difference between the reproduction target characteristics of the first sound signal and the characteristics of the second sound signal is further based on a volume of air inside the headphone, and wherein the volume of air varies based on the physical characteristics of the wearers.