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Overview

Patent number: 20170311078
Title: Dynamic low-frequency enhancement method and system based on equal loudness contour
Processing time: 0.8 seconds
Number of claims: 2 independent and 20 total
Claims for fees: 2 independent and 20 total (excluding canceled and including multiple dependencies)
Abstract: 131 words

Claim Tree

  • Claim 1
    • Claim 2
      • Claim 3
      • Claim 4
      • Claim 5
        • Claim 9
        • Claim 10
      • Claim 6
        • Claim 12
          • Claim 13
          • Claim 14
          • Claim 15
            • Claim 19
            • Claim 20
    • Claim 7
    • Claim 8
  • Claim 11
    • Claim 16
    • Claim 17
    • Claim 18

Numbering and Dependency Errors
Punctuation warnings.
 11. A dynamic low-frequency enhancement system based on equal loudness contour, wherein, the system comprises: an audio sampling module, a frequency-division processing module, a low-frequency band pass filter, a high-frequency band pass filter, an original-audio frequency band pass filter, an AGC module, a low-pass filtering enhancement module and a mixer; an input end, a low-frequency output end, a high-frequency output end and an original-audio frequency output end of the frequency-division processing module are respectively connected to the audio sampling module, the low-frequency band pass filter, the high-frequency band pass filter and the original-audio frequency band pass filter correspondingly; the low-frequency band pass filter is further connected to the mixer through the AGC module, the high-frequency band pass filter is directly connected to the mixer, and the original-audio frequency band pass filter is connected to the mixer through the low-pass filtering enhancement module; and superfluous "and"?
the audio sampling module is configured to collect an input audio signal;
the frequency-division processing module is configured to perform frequency-division processing on the input audio signal, extract a high-frequency signal and a low-frequency signal to transmit respectively through the low-frequency band pass filter and the high-frequency band pass filter, and reserve one path of original audio signal to transmit through the original-audio frequency band pass filter;
the AGC module is configured to perform dynamic gain processing on the low-frequency signal adopting an AGC algorithm; missing "and"?
the low-pass filtering enhancement module is configured to perform low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and
the mixer is configured to subject the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.
Claim has different type than parent.
Claim should depend from most recent independent claim.
12. The dynamic low-frequency enhancement system based on equal loudness contour according to claim 6, wherein, the AGC module comprises:
a sound pressure level detection unit configured to detect the sound pressure level of the low-frequency signal; and
a comparison unit which configured to determine the range which the sound pressure level falls in;
wherein the sound pressure level includes a noise domain, a general signal domain and an expected sound pressure domain.
Punctuation warnings.
 14. The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to perform gain amplification processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely an expected sound pressure domain or enters the expected sound pressure domain, when the sound pressure level is in the general signal domain, missing period?

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1.A dynamic low-frequency enhancement method based on equal loudness contour, wherein, the method comprises:
collecting an input audio signal;
performing frequency-division processing on the input audio signal, extracting a high-frequency signal and a low-frequency signal to transmit respectively, and reserving one path of original audio signal;
performing dynamic gain processing on the low-frequency signal adopting an Automatic Gain Control (AGC) algorithm, and performing low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and
subjecting the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.

2.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, performing dynamic gain processing on the low-frequency signal adopting an AGC algorithm specifically comprises:
detecting the sound pressure level of the low-frequency signal; and
determining the range which the sound pressure level falls in,
wherein the sound pressure level includes a noise domain, a general signal domain and an expected sound pressure domain.

3.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the noise domain, performing zero gain processing on the low-frequency signal.

4.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the general signal domain, performing gain amplification processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely an expected sound pressure domain or enters the expected sound pressure domain.

5.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the expected sound pressure domain, controlling the gain of the low-frequency signal by controlling a gain coefficient, thereby the sound pressure level of the low-frequency signal is kept in the expected sound pressure domain;
when the sound pressure level is greater than the expected sound pressure domain, performing negative gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal enters the expected sound pressure domain.

6.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

7.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

8.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, the low-frequency signal is a low-frequency band pure tone signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band pure tone signal with frequency greater than or equal to 1500 HZ in the input audio signal.

9.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 5, wherein, the expected sound pressure domain can be divided into two ranges, including: −56 dB to 12 dB and 12 dB to 24 dB; when the sound pressure level of the low-frequency signal is in the area of −56 dB to 12 dB, a gain coefficient greater than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely 12 dB; when the sound pressure level of the low-frequency signal is in the range of 12 dB to 24 dB, a gain coefficient less than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal is always kept in the expected sound pressure domain.

10.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 5, wherein, the low-frequency signal, the high-frequency signal and the original audio signal obtained after the frequency-division processing are correspondingly transmitted through three paths of different band pass filters, respectively.

11.A dynamic low-frequency enhancement system based on equal loudness contour, wherein, the system comprises: an audio sampling module, a frequency-division processing module, a low-frequency band pass filter, a high-frequency band pass filter, an original-audio frequency band pass filter, an AGC module, a low-pass filtering enhancement module and a mixer; an input end, a low-frequency output end, a high-frequency output end and an original-audio frequency output end of the frequency-division processing module are respectively connected to the audio sampling module, the low-frequency band pass filter, the high-frequency band pass filter and the original-audio frequency band pass filter correspondingly; the low-frequency band pass filter is further connected to the mixer through the AGC module, the high-frequency band pass filter is directly connected to the mixer, and the original-audio frequency band pass filter is connected to the mixer through the low-pass filtering enhancement module; and
the audio sampling module is configured to collect an input audio signal;
the frequency-division processing module is configured to perform frequency-division processing on the input audio signal, extract a high-frequency signal and a low-frequency signal to transmit respectively through the low-frequency band pass filter and the high-frequency band pass filter, and reserve one path of original audio signal to transmit through the original-audio frequency band pass filter;
the AGC module is configured to perform dynamic gain processing on the low-frequency signal adopting an AGC algorithm;
the low-pass filtering enhancement module is configured to perform low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and
the mixer is configured to subject the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.

12.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 6, wherein, the AGC module comprises:
a sound pressure level detection unit configured to detect the sound pressure level of the low-frequency signal; and
a comparison unit which configured to determine the range which the sound pressure level falls in;
wherein the sound pressure level includes a noise domain, a general signal domain and an expected sound pressure domain.

13.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to perform zero gain processing on the low-frequency signal, when the sound pressure level is in the noise domain.

14.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to perform gain amplification processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely an expected sound pressure domain or enters the expected sound pressure domain, when the sound pressure level is in the general signal domain,

15.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to control the gain of the low-frequency signal by controlling a gain coefficient, thereby the sound pressure level of the low-frequency signal is kept in the expected sound pressure domain, when the sound pressure level is in the expected sound pressure domain; and configured to perform negative gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal enters the expected sound pressure domain, when the sound pressure level is greater than the expected sound pressure domain.

16.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

17.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

18.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the low-frequency signal is a low-frequency band signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band signal with frequency greater than or equal to 1500 HZ in the input audio signal.

19.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 15, wherein, the expected sound pressure domain can be divided into two ranges, including: −56 dB to 12 dB and 12 dB to 24 dB; when the sound pressure level of the low-frequency signal is in the area of −56 dB to 12 dB, a gain coefficient greater than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely 12 dB; when the sound pressure level of the low-frequency signal is in the range of 12 dB to 24 dB, a gain coefficient less than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal is always kept in the expected sound pressure domain.

20.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 15, wherein, the low-frequency signal, the high-frequency signal and the original audio signal obtained after the frequency-division processing are correspondingly transmitted through three paths of different band pass filters, respectively.

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1.A dynamic low-frequency enhancement method based on equal loudness contour, wherein, the method comprises:
collecting an input audio signal;
performing frequency-division processing on the input audio signal, extracting a high-frequency signal and a low-frequency signal to transmit respectively, and reserving one path of original audio signal;
performing dynamic gain processing on the low-frequency signal adopting an Automatic Gain Control (AGC) algorithm, and performing low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and
subjecting the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.

2.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, performing dynamic gain processing on the low-frequency signal adopting an AGC algorithm specifically comprises:
detecting the sound pressure level of the low-frequency signal; and
determining the range which the sound pressure level falls in,
wherein the sound pressure level includes a noise domain, a general signal domain and an expected sound pressure domain.

3.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the noise domain, performing zero gain processing on the low-frequency signal.

4.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the general signal domain, performing gain amplification processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely an expected sound pressure domain or enters the expected sound pressure domain.

5.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the expected sound pressure domain, controlling the gain of the low-frequency signal by controlling a gain coefficient, thereby the sound pressure level of the low-frequency signal is kept in the expected sound pressure domain;
when the sound pressure level is greater than the expected sound pressure domain, performing negative gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal enters the expected sound pressure domain.

6.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

7.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

8.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, the low-frequency signal is a low-frequency band pure tone signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band pure tone signal with frequency greater than or equal to 1500 HZ in the input audio signal.

9.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 5, wherein, the expected sound pressure domain can be divided into two ranges, including: −56 dB to 12 dB and 12 dB to 24 dB; when the sound pressure level of the low-frequency signal is in the area of −56 dB to 12 dB, a gain coefficient greater than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely 12 dB; when the sound pressure level of the low-frequency signal is in the range of 12 dB to 24 dB, a gain coefficient less than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal is always kept in the expected sound pressure domain.

10.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 5, wherein, the low-frequency signal, the high-frequency signal and the original audio signal obtained after the frequency-division processing are correspondingly transmitted through three paths of different band pass filters, respectively.

11.A dynamic low-frequency enhancement system based on equal loudness contour, wherein, the system comprises: an audio sampling module, a frequency-division processing module, a low-frequency band pass filter, a high-frequency band pass filter, an original-audio frequency band pass filter, an AGC module, a low-pass filtering enhancement module and a mixer; an input end, a low-frequency output end, a high-frequency output end and an original-audio frequency output end of the frequency-division processing module are respectively connected to the audio sampling module, the low-frequency band pass filter, the high-frequency band pass filter and the original-audio frequency band pass filter correspondingly; the low-frequency band pass filter is further connected to the mixer through the AGC module, the high-frequency band pass filter is directly connected to the mixer, and the original-audio frequency band pass filter is connected to the mixer through the low-pass filtering enhancement module; and
the audio sampling module is configured to collect an input audio signal;
the frequency-division processing module is configured to perform frequency-division processing on the input audio signal, extract a high-frequency signal and a low-frequency signal to transmit respectively through the low-frequency band pass filter and the high-frequency band pass filter, and reserve one path of original audio signal to transmit through the original-audio frequency band pass filter;
the AGC module is configured to perform dynamic gain processing on the low-frequency signal adopting an AGC algorithm;
the low-pass filtering enhancement module is configured to perform low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and
the mixer is configured to subject the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.

12.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 6, wherein, the AGC module comprises:
a sound pressure level detection unit configured to detect the sound pressure level of the low-frequency signal; and
a comparison unit which configured to determine the range which the sound pressure level falls in;
wherein the sound pressure level includes a noise domain, a general signal domain and an expected sound pressure domain.

13.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to perform zero gain processing on the low-frequency signal, when the sound pressure level is in the noise domain.

14.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to perform gain amplification processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely an expected sound pressure domain or enters the expected sound pressure domain, when the sound pressure level is in the general signal domain,

15.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to control the gain of the low-frequency signal by controlling a gain coefficient, thereby the sound pressure level of the low-frequency signal is kept in the expected sound pressure domain, when the sound pressure level is in the expected sound pressure domain; and configured to perform negative gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal enters the expected sound pressure domain, when the sound pressure level is greater than the expected sound pressure domain.

16.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

17.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

18.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the low-frequency signal is a low-frequency band signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band signal with frequency greater than or equal to 1500 HZ in the input audio signal.

19.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 15, wherein, the expected sound pressure domain can be divided into two ranges, including: −56 dB to 12 dB and 12 dB to 24 dB; when the sound pressure level of the low-frequency signal is in the area of −56 dB to 12 dB, a gain coefficient greater than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely 12 dB; when the sound pressure level of the low-frequency signal is in the range of 12 dB to 24 dB, a gain coefficient less than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal is always kept in the expected sound pressure domain.

20.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 15, wherein, the low-frequency signal, the high-frequency signal and the original audio signal obtained after the frequency-division processing are correspondingly transmitted through three paths of different band pass filters, respectively.

1.A dynamic low-frequency enhancement method based on equal loudness contour, wherein, the method comprises:
collecting an input audio signal;
performing frequency-division processing on the input audio signal, extracting a high-frequency signal and a low-frequency signal to transmit respectively, and reserving one path of original audio signal;
performing dynamic gain processing on the low-frequency signal adopting an Automatic Gain Control (AGC) algorithm, and performing low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and
subjecting the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.

2.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, performing dynamic gain processing on the low-frequency signal adopting an AGC algorithm specifically comprises:
detecting the sound pressure level of the low-frequency signal; and
determining the range which the sound pressure level falls in,
wherein the sound pressure level includes a noise domain, a general signal domain and an expected sound pressure domain.

3.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the noise domain, performing zero gain processing on the low-frequency signal.

4.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the general signal domain, performing gain amplification processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely an expected sound pressure domain or enters the expected sound pressure domain.

5.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the expected sound pressure domain, controlling the gain of the low-frequency signal by controlling a gain coefficient, thereby the sound pressure level of the low-frequency signal is kept in the expected sound pressure domain;
when the sound pressure level is greater than the expected sound pressure domain, performing negative gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal enters the expected sound pressure domain.

6.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

7.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

8.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, the low-frequency signal is a low-frequency band pure tone signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band pure tone signal with frequency greater than or equal to 1500 HZ in the input audio signal.

9.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 5, wherein, the expected sound pressure domain can be divided into two ranges, including: −56 dB to 12 dB and 12 dB to 24 dB; when the sound pressure level of the low-frequency signal is in the area of −56 dB to 12 dB, a gain coefficient greater than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely 12 dB; when the sound pressure level of the low-frequency signal is in the range of 12 dB to 24 dB, a gain coefficient less than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal is always kept in the expected sound pressure domain.

10.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 5, wherein, the low-frequency signal, the high-frequency signal and the original audio signal obtained after the frequency-division processing are correspondingly transmitted through three paths of different band pass filters, respectively.

11.A dynamic low-frequency enhancement system based on equal loudness contour, wherein, the system comprises: an audio sampling module, a frequency-division processing module, a low-frequency band pass filter, a high-frequency band pass filter, an original-audio frequency band pass filter, an AGC module, a low-pass filtering enhancement module and a mixer; an input end, a low-frequency output end, a high-frequency output end and an original-audio frequency output end of the frequency-division processing module are respectively connected to the audio sampling module, the low-frequency band pass filter, the high-frequency band pass filter and the original-audio frequency band pass filter correspondingly; the low-frequency band pass filter is further connected to the mixer through the AGC module, the high-frequency band pass filter is directly connected to the mixer, and the original-audio frequency band pass filter is connected to the mixer through the low-pass filtering enhancement module; and
the audio sampling module is configured to collect an input audio signal;
the frequency-division processing module is configured to perform frequency-division processing on the input audio signal, extract a high-frequency signal and a low-frequency signal to transmit respectively through the low-frequency band pass filter and the high-frequency band pass filter, and reserve one path of original audio signal to transmit through the original-audio frequency band pass filter;
the AGC module is configured to perform dynamic gain processing on the low-frequency signal adopting an AGC algorithm;
the low-pass filtering enhancement module is configured to perform low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and
the mixer is configured to subject the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.

12.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 6, wherein, the AGC module comprises:
a sound pressure level detection unit configured to detect the sound pressure level of the low-frequency signal; and
a comparison unit which configured to determine the range which the sound pressure level falls in;
wherein the sound pressure level includes a noise domain, a general signal domain and an expected sound pressure domain.

13.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to perform zero gain processing on the low-frequency signal, when the sound pressure level is in the noise domain.

14.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to perform gain amplification processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely an expected sound pressure domain or enters the expected sound pressure domain, when the sound pressure level is in the general signal domain,

15.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to control the gain of the low-frequency signal by controlling a gain coefficient, thereby the sound pressure level of the low-frequency signal is kept in the expected sound pressure domain, when the sound pressure level is in the expected sound pressure domain; and configured to perform negative gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal enters the expected sound pressure domain, when the sound pressure level is greater than the expected sound pressure domain.

16.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

17.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

18.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the low-frequency signal is a low-frequency band signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band signal with frequency greater than or equal to 1500 HZ in the input audio signal.

19.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 15, wherein, the expected sound pressure domain can be divided into two ranges, including: −56 dB to 12 dB and 12 dB to 24 dB; when the sound pressure level of the low-frequency signal is in the area of −56 dB to 12 dB, a gain coefficient greater than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely 12 dB; when the sound pressure level of the low-frequency signal is in the range of 12 dB to 24 dB, a gain coefficient less than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal is always kept in the expected sound pressure domain.

20.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 15, wherein, the low-frequency signal, the high-frequency signal and the original audio signal obtained after the frequency-division processing are correspondingly transmitted through three paths of different band pass filters, respectively.

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1.A dynamic low-frequency enhancement method based on equal loudness contour, wherein, the method comprises:
collecting an input audio signal;
performing frequency-division processing on the input audio signal, extracting a high-frequency signal and a low-frequency signal to transmit respectively, and reserving one path of original audio signal;
performing dynamic gain processing on the low-frequency signal adopting an Automatic Gain Control (AGC) algorithm, and performing low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and
subjecting the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.

2.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, performing dynamic gain processing on the low-frequency signal adopting an AGC algorithm specifically comprises:
detecting the sound pressure level of the low-frequency signal; and
determining the range which the sound pressure level falls in,
wherein the sound pressure level includes a noise domain, a general signal domain and an expected sound pressure domain.

3.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the noise domain, performing zero gain processing on the low-frequency signal.

4.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the general signal domain, performing gain amplification processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely an expected sound pressure domain or enters the expected sound pressure domain.

5.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the expected sound pressure domain, controlling the gain of the low-frequency signal by controlling a gain coefficient, thereby the sound pressure level of the low-frequency signal is kept in the expected sound pressure domain;
when the sound pressure level is greater than the expected sound pressure domain, performing negative gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal enters the expected sound pressure domain.

6.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

7.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

8.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, the low-frequency signal is a low-frequency band pure tone signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band pure tone signal with frequency greater than or equal to 1500 HZ in the input audio signal.

9.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 5, wherein, the expected sound pressure domain can be divided into two ranges, including: −56 dB to 12 dB and 12 dB to 24 dB; when the sound pressure level of the low-frequency signal is in the area of −56 dB to 12 dB, a gain coefficient greater than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely 12 dB; when the sound pressure level of the low-frequency signal is in the range of 12 dB to 24 dB, a gain coefficient less than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal is always kept in the expected sound pressure domain.

10.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 5, wherein, the low-frequency signal, the high-frequency signal and the original audio signal obtained after the frequency-division processing are correspondingly transmitted through three paths of different band pass filters, respectively.

11.A dynamic low-frequency enhancement system based on equal loudness contour, wherein, the system comprises: an audio sampling module, a frequency-division processing module, a low-frequency band pass filter, a high-frequency band pass filter, an original-audio frequency band pass filter, an AGC module, a low-pass filtering enhancement module and a mixer; an input end, a low-frequency output end, a high-frequency output end and an original-audio frequency output end of the frequency-division processing module are respectively connected to the audio sampling module, the low-frequency band pass filter, the high-frequency band pass filter and the original-audio frequency band pass filter correspondingly; the low-frequency band pass filter is further connected to the mixer through the AGC module, the high-frequency band pass filter is directly connected to the mixer, and the original-audio frequency band pass filter is connected to the mixer through the low-pass filtering enhancement module; and
the audio sampling module is configured to collect an input audio signal;
the frequency-division processing module is configured to perform frequency-division processing on the input audio signal, extract a high-frequency signal and a low-frequency signal to transmit respectively through the low-frequency band pass filter and the high-frequency band pass filter, and reserve one path of original audio signal to transmit through the original-audio frequency band pass filter;
the AGC module is configured to perform dynamic gain processing on the low-frequency signal adopting an AGC algorithm;
the low-pass filtering enhancement module is configured to perform low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and
the mixer is configured to subject the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.

12.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 6, wherein, the AGC module comprises:
a sound pressure level detection unit configured to detect the sound pressure level of the low-frequency signal; and
a comparison unit which configured to determine the range which the sound pressure level falls in;
wherein the sound pressure level includes a noise domain, a general signal domain and an expected sound pressure domain.

13.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to perform zero gain processing on the low-frequency signal, when the sound pressure level is in the noise domain.

14.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to perform gain amplification processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely an expected sound pressure domain or enters the expected sound pressure domain, when the sound pressure level is in the general signal domain,

15.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to control the gain of the low-frequency signal by controlling a gain coefficient, thereby the sound pressure level of the low-frequency signal is kept in the expected sound pressure domain, when the sound pressure level is in the expected sound pressure domain; and configured to perform negative gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal enters the expected sound pressure domain, when the sound pressure level is greater than the expected sound pressure domain.

16.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

17.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

18.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the low-frequency signal is a low-frequency band signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band signal with frequency greater than or equal to 1500 HZ in the input audio signal.

19.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 15, wherein, the expected sound pressure domain can be divided into two ranges, including: −56 dB to 12 dB and 12 dB to 24 dB; when the sound pressure level of the low-frequency signal is in the area of −56 dB to 12 dB, a gain coefficient greater than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely 12 dB; when the sound pressure level of the low-frequency signal is in the range of 12 dB to 24 dB, a gain coefficient less than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal is always kept in the expected sound pressure domain.

20.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 15, wherein, the low-frequency signal, the high-frequency signal and the original audio signal obtained after the frequency-division processing are correspondingly transmitted through three paths of different band pass filters, respectively.

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CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of PCT/CN2015/087581 filed Aug. 20, 2015, which claims priority to CN 201510127703.5 filed Mar. 23, 2015, both of which are incorporated by reference.

TECHNICAL FIELD

[0002] The disclosure relates to the field of audio signal processing technologies, and in particular to a dynamic low-frequency enhancement method based on equal loudness contour and a dynamic low-frequency enhancement system based on equal loudness contour.

BACKGROUND

[0003] Audio stream output by earphone can be viewed as the superposition of many sine waves of different frequencies; low-frequency enhancement is to improve the sound pressure level of low-frequency components in the audio stream by filtering and other methods, so that the voice sounds more vigorous.

[0004] The low-frequency enhancement in existing technologies mainly adopts filter technologies, and combines different filters and other components to meet different requirements. However, adopting pure filter technologies to perform low-frequency enhancement has certain limitation: it is cumbersome to adjust voice volume (actually to amplify/reduce the amplitude of the waveform of an audio signal so as to change the sound pressure) in the normal use of earphone, it can be known from the description of an equal loudness contour that pure tones of different frequencies have different loudness at different sound pressure levels; therefore, in actual application, when low-frequency enhancement is performed on the audio stream output by an earphone, different gains need to be added to signals of different frequencies at different sound pressure levels, so that gains of signals of different frequencies in the output audio signal all meet the tendency of the equal loudness contour when voice volume is adjusted and an optimal low-frequency enhancement effect is achieved; however, this requirement cannot be met in static filter combination in existing technologies.

SUMMARY

[0005] The purpose of the embodiment of the disclosure is to provide a dynamic low-frequency enhancement system and method based on equal loudness contour so as to solve the above problem that different gains cannot be added to signals of different frequencies at different sound pressure levels in static filter combination.

[0006] The embodiment of the disclosure is realized as follows: a dynamic low-frequency enhancement method based on equal loudness contour includes:

[0011] In the dynamic low-frequency enhancement method based on equal loudness contour described in the embodiment of the disclosure, performing dynamic gain processing on the low-frequency signal adopting an AGC algorithm specifically includes:

[0015] In the dynamic low-frequency enhancement method based on equal loudness contour described in the embodiment of the disclosure, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

[0016] In the dynamic low-frequency enhancement method based on equal loudness contour described in the embodiment of the disclosure, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

[0017] In the dynamic low-frequency enhancement method based on equal loudness contour described in the embodiment of the disclosure, the low-frequency signal is a low-frequency band signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band signal with frequency greater than or equal to 1500 HZ in the input audio signal.

[0018] Another purpose of the embodiment of the disclosure is to provide a dynamic low-frequency enhancement system based on equal loudness contour, including: an audio sampling module, a frequency-division processing module, a low-frequency band pass filter, a high-frequency band pass filter, an original-audio frequency band pass filter, an AGC module, a low-pass filtering enhancement module and a mixer; an input end, a low-frequency output end, a high-frequency output end and an original-audio frequency output end of the frequency-division processing module are respectively connected to the audio sampling module, the low-frequency band pass filter, the high-frequency band pass filter and the original-audio frequency band pass filter correspondingly; the low-frequency band pass filter is further connected to the mixer through the AGC module, the high-frequency band pass filter is directly connected to the mixer, and the original-audio frequency band pass filter is connected to the mixer through the low-pass filtering enhancement module; wherein

[0024] In the dynamic low-frequency enhancement system based on equal loudness contour described in the embodiment of the disclosure, the AGC module includes:

[0028] In the dynamic low-frequency enhancement system based on equal loudness contour described in the embodiment of the disclosure, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

[0029] In the dynamic low-frequency enhancement system based on equal loudness contour described in the embodiment of the disclosure, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

[0030] In the dynamic low-frequency enhancement system based on equal loudness contour described in the embodiment of the disclosure, the low-frequency signal is a low-frequency band signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band signal with frequency greater than or equal to 1500 HZ in the input audio signal.

[0031] The dynamic low-frequency enhancement method and system based on equal loudness contour provided by the embodiment of the disclosure have benefits as follows:

[0032] The embodiment of the disclosure first performs frequency-division processing on an input audio signal after collecting the input audio signal, extracts a high-frequency signal and a low-frequency signal to transmit respectively, and reserves one path of original audio signal; then performs dynamic gain processing on the low-frequency signal adopting an AGC algorithm, and performs low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and finally subjects the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1. Thus, different gains can be added to signals of different frequencies at different sound pressure levels, so that gains of signals of different frequencies in the output audio signal all meet the tendency of a equal loudness contour when voice volume is adjusted, an optimal low-frequency enhancement effect can be achieved, and the stability of the low-frequency enhancement effect can be ensured.

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a flowchart of a dynamic low-frequency enhancement method based on equal loudness contour provided by the embodiment of the disclosure.

[0034] FIG. 2 is a specific flowchart of S 103 of the dynamic low-frequency enhancement method based on equal loudness contour provided by the embodiment of the disclosure.

[0035] FIG. 3 is a structure diagram of a dynamic low-frequency enhancement system based on equal loudness contour provided by the embodiment of the disclosure.

[0036] FIG. 4 is a structure diagram of an AGC module in the dynamic low-frequency enhancement system based on equal loudness contour provided by the embodiment of the disclosure.

CLAIMS

1.A dynamic low-frequency enhancement method based on equal loudness contour, wherein, the method comprises:
collecting an input audio signal;
performing frequency-division processing on the input audio signal, extracting a high-frequency signal and a low-frequency signal to transmit respectively, and reserving one path of original audio signal;
performing dynamic gain processing on the low-frequency signal adopting an Automatic Gain Control (AGC) algorithm, and performing low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and
subjecting the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.

2.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, performing dynamic gain processing on the low-frequency signal adopting an AGC algorithm specifically comprises:
detecting the sound pressure level of the low-frequency signal; and
determining the range which the sound pressure level falls in,
wherein the sound pressure level includes a noise domain, a general signal domain and an expected sound pressure domain.

3.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the noise domain, performing zero gain processing on the low-frequency signal.

4.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the general signal domain, performing gain amplification processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely an expected sound pressure domain or enters the expected sound pressure domain.

5.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, when the sound pressure level is in the expected sound pressure domain, controlling the gain of the low-frequency signal by controlling a gain coefficient, thereby the sound pressure level of the low-frequency signal is kept in the expected sound pressure domain;
when the sound pressure level is greater than the expected sound pressure domain, performing negative gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal enters the expected sound pressure domain.

6.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 2, wherein, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

7.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

8.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 1, wherein, the low-frequency signal is a low-frequency band pure tone signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band pure tone signal with frequency greater than or equal to 1500 HZ in the input audio signal.

9.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 5, wherein, the expected sound pressure domain can be divided into two ranges, including: −56 dB to 12 dB and 12 dB to 24 dB; when the sound pressure level of the low-frequency signal is in the area of −56 dB to 12 dB, a gain coefficient greater than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely 12 dB; when the sound pressure level of the low-frequency signal is in the range of 12 dB to 24 dB, a gain coefficient less than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal is always kept in the expected sound pressure domain.

10.The dynamic low-frequency enhancement method based on equal loudness contour according to claim 5, wherein, the low-frequency signal, the high-frequency signal and the original audio signal obtained after the frequency-division processing are correspondingly transmitted through three paths of different band pass filters, respectively.

11.A dynamic low-frequency enhancement system based on equal loudness contour, wherein, the system comprises: an audio sampling module, a frequency-division processing module, a low-frequency band pass filter, a high-frequency band pass filter, an original-audio frequency band pass filter, an AGC module, a low-pass filtering enhancement module and a mixer; an input end, a low-frequency output end, a high-frequency output end and an original-audio frequency output end of the frequency-division processing module are respectively connected to the audio sampling module, the low-frequency band pass filter, the high-frequency band pass filter and the original-audio frequency band pass filter correspondingly; the low-frequency band pass filter is further connected to the mixer through the AGC module, the high-frequency band pass filter is directly connected to the mixer, and the original-audio frequency band pass filter is connected to the mixer through the low-pass filtering enhancement module; and
the audio sampling module is configured to collect an input audio signal;
the frequency-division processing module is configured to perform frequency-division processing on the input audio signal, extract a high-frequency signal and a low-frequency signal to transmit respectively through the low-frequency band pass filter and the high-frequency band pass filter, and reserve one path of original audio signal to transmit through the original-audio frequency band pass filter;
the AGC module is configured to perform dynamic gain processing on the low-frequency signal adopting an AGC algorithm;
the low-pass filtering enhancement module is configured to perform low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and
the mixer is configured to subject the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.

12.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 6, wherein, the AGC module comprises:
a sound pressure level detection unit configured to detect the sound pressure level of the low-frequency signal; and
a comparison unit which configured to determine the range which the sound pressure level falls in;
wherein the sound pressure level includes a noise domain, a general signal domain and an expected sound pressure domain.

13.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to perform zero gain processing on the low-frequency signal, when the sound pressure level is in the noise domain.

14.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to perform gain amplification processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely an expected sound pressure domain or enters the expected sound pressure domain, when the sound pressure level is in the general signal domain,

15.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 12, wherein, the AGC module also comprises a gain adjustment unit configured to control the gain of the low-frequency signal by controlling a gain coefficient, thereby the sound pressure level of the low-frequency signal is kept in the expected sound pressure domain, when the sound pressure level is in the expected sound pressure domain; and configured to perform negative gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal enters the expected sound pressure domain, when the sound pressure level is greater than the expected sound pressure domain.

16.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the range of the sound pressure level of the noise domain is less than or equal to −80 dB, the range of the sound pressure level of the general signal domain is −80 dB to −56 dB, and the range of the sound pressure level of the expected sound pressure domain is −56 dB to −24 dB.

17.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the weight coefficients a, b, c of the high frequency signal, the processed low-frequency signal and the processed original audio signal all have a value of ⅓.

18.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 11, wherein, the low-frequency signal is a low-frequency band signal with frequency less than or equal to 130 HZ in the input audio signal, and the high-frequency signal is a high-frequency band signal with frequency greater than or equal to 1500 HZ in the input audio signal.

19.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 15, wherein, the expected sound pressure domain can be divided into two ranges, including: −56 dB to 12 dB and 12 dB to 24 dB; when the sound pressure level of the low-frequency signal is in the area of −56 dB to 12 dB, a gain coefficient greater than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal approaches infinitely 12 dB; when the sound pressure level of the low-frequency signal is in the range of 12 dB to 24 dB, a gain coefficient less than 1 is adopted to perform gain processing on the low-frequency signal, thereby the sound pressure level of the low-frequency signal is always kept in the expected sound pressure domain.

20.The dynamic low-frequency enhancement system based on equal loudness contour according to claim 15, wherein, the low-frequency signal, the high-frequency signal and the original audio signal obtained after the frequency-division processing are correspondingly transmitted through three paths of different band pass filters, respectively.

ABSTRACT

A method comprises: collecting an input audio signal; performing frequency-division processing on the input audio signal, extracting a high-frequency signal and a low-frequency signal to transmit respectively, and reserving one path of original audio signal; performing dynamic gain processing on the low-frequency signal adopting an Automatic Gain Control (AGC) algorithm, and performing low-pass filtering enhancement processing on the original audio signal adopting a static low-frequency enhancement algorithm; and subjecting the high-frequency signal, the processed low-frequency signal and the processed original audio signal to weighted summation to obtain a final output audio signal, the weight coefficients of the high frequency signal, the processed low-frequency signal and the processed original audio signal being a, b and c respectively, where the values of a, b and c range from 0 to 1, and a+b+c=1.