Clicking noise detection in a digital audio signal
View Patent ↗In a method (M) to detect a noise signal (PS 1 , PS 2 , PS 3 ) in a digital audio signal (EAS), it is provided that the audio signal (EAS) is divided into successive signal sections (SAS), and the energy contents of successive signal sections (SAS) are determined, and the energy contents of a signal section (SAS) are evaluated in relation to an energy threshold (ET), and that the occurrence of at least one high-energy signal section having an energy content above the energy threshold (ET), and the occurrence of at least one signal section (SAS) preceding the at least one high-energy signal section and having an energy content below the energy threshold (ET), and the occurrence of at least one signal section (SAS) following the at least one high-energy signal section and having an energy content below the energy threshold (ET) are detected, and that a quantity of signal sections (SAS) that precede the at least one high-energy signal section and a quantity of high-energy signal sections and a quantity of signal sections (SAS) that follow the high-energy signal section are counted.
1. A method to detect at least one noise signal in a digital audio signal using at least one processor, the method comprising:
dividing the digital audio signal into a plurality of successive signal sections;
determining, by the at least one processor, an energy content for each of the plurality of successive signal sections;
comparing the energy content for each of the plurality of successive signal sections, to an energy threshold;
detecting, among the plurality of successive signal sections, at least one high-energy signal section having an energy content greater than the energy threshold, wherein the at least one high-energy signal section has at least one preceding signal section having an energy content less than the energy threshold and at least one following signal section having an energy content less than the energy threshold;
counting a first quantity of the at least one preceding signal section, a second quantity of the at least one high-energy signal section, and a third quantity of the at least one following signal section; and
determining if the at least one high-energy signal section represents the at least one noise signal based, at least in part, on the first quantity, the second quantity, and the third quantity.
2. The method of claim 1 , wherein the energy content for each of the plurality of successive signal sections is determined in accordance with the formula:
E
=
10
log
10
(
1
N
∑
k
=
1
N
S
k
2
)
;
wherein S k represents magnitudes of signal amplitudes within each of the plurality of successive signal sections, and N represents a total number of signal amplitudes within each of the plurality of successive signal sections.
3. The method of claim 1 , further comprising:
determining the energy threshold continuously from the digital audio signal based, at least in part, on a histogram method using the energy content calculated for each of the successive signal sections, a background level, and a ratio between a useful-signal level and a noise level of the digital audio signal.
4. The method of claim 1 , wherein a duration of each of the successive signal sections is between two milliseconds and ten milliseconds.
5. The method of claim 1 , wherein a duration of each of the successive signal sections is five milliseconds.
6. The method of claim 1 , wherein it is determined that the at least one high-energy signal section represents the at least one noise signal when the first quantity is equal to or greater than 9, the second quantity is between 3 and 7, and the third quantity is equal to or greater than 30.
7. The method of claim 1 , further comprising:
determining at least one additional high-energy signal section follows the at least one following signal section having an energy content less than the energy threshold;
wherein counting the second quantity comprises counting the at least one high-energy signal section and the at least one additional high-energy signal section.
8. An apparatus for detecting a noise signal in a digital audio signal the apparatus comprising:
a divider circuit configured to divide the digital audio signal into a plurality of signal sections;
a determination circuit configured to determine the energy content of the plurality of signal sections
an evaluation circuit configured to evaluate the energy content of each of the plurality of signal sections relative to an energy threshold; and
a detection circuit configured to detect, among the plurality of signal sections, the occurrence of:
at least one high-energy signal section having an energy content greater than the energy threshold,
at least one preceding signal section preceding the at least one high-energy signal section and having an energy content less than the energy threshold, and
at least one following signal section following the at least one high-energy signal section and having an energy content less than the energy threshold; and
a counting circuit configured to count a first quantity of preceding signal sections, a second quantity of high-energy signal sections, and a third quantity of following signal sections.
9. The apparatus of claim 8 , further comprising:
a supply circuit configured to supply an output audio signal, wherein the output audio signal comprises less noise than the digital audio signal.
10. The apparatus of claim 8 , wherein one or more of the divider circuit, the determination circuit, the evaluation circuit, the detection circuit, and the counting circuit are implemented by at least one programmed processor.
11. The apparatus of claim 9 , wherein the supply circuit is implemented by at least one programmed processor.
12. A computer-readable medium comprising a plurality of software code sections that, when executed by a computer, perform a method comprising:
dividing a digital audio signal into a plurality of signal sections;
comparing an energy content determined for each of the plurality of signal sections to an energy threshold;
detecting, among the plurality of signal sections, at least one high-energy signal section having an energy content greater than the energy threshold, wherein the at least one high-energy signal section has at least one preceding signal section having an energy content less than the energy threshold and at least one following signal section having an energy content less than the energy threshold;
counting a first quantity of the at least one preceding signal section, a second quantity of the at least one high-energy signal section, and a third quantity of the at least one following signal section; and
determining if the at least one high-energy signal section represents at least one noise signal based, at least in part, on the first quantity, the second quantity, and the third quantity.
13. The computer-readable medium of claim 12 , wherein the energy content for each of the plurality of signal sections is determined in accordance with the formula:
E
=
10
log
10
(
1
N
∑
k
=
1
N
S
k
2
)
;
wherein S k represents magnitudes of signal amplitudes within each of the plurality of signal sections, and N represents a total number of signal amplitudes within each of the plurality of signal sections.
14. The computer-readable medium of claim 12 , wherein the method further comprises:
determining the energy threshold continuously from the digital audio signal based, at least in part, on a histogram method using the energy content calculated for each of the signal sections, a background level, and a ratio between a useful-signal level and a noise level of the digital audio signal.
15. The computer-readable medium of claim 12 , wherein a duration of each of the signal sections is between two milliseconds and ten milliseconds.
16. The computer-readable medium of claim 12 , wherein a duration of each of the signal sections is five milliseconds.
17. The computer-readable medium of claim 12 , wherein it is determined that the at least one high-energy signal section represents the at least one noise signal when the first quantity is equal to or greater than 9, the second quantity is between 3 and 7, and the third quantity is equal to or greater than 30.
18. The computer-readable medium of claim 12 , wherein the method further comprises:
determining if at least one additional high-energy signal section is present following the at least one following signal section having an energy content less than the energy threshold;
wherein counting the second quantity comprises counting the at least one high-energy signal section and the at least one additional high-energy signal section, if present.