التفاصيل البيبلوغرافية
| العنوان: |
NOISE REDUCING DEVICE AND NOISE DETERMINING METHOD |
| Document Number: |
20100260353 |
| تاريخ النشر: |
October 14, 2010 |
| Appl. No: |
12/718508 |
| Application Filed: |
March 05, 2010 |
| مستخلص: |
A noise reducing device includes: a sound-signal input unit that inputs a sound signal; a time-to-frequency converting unit that converts the input sound signal obtained by being input by the sound-signal input unit into a frequency signal; a patterning unit that calculates, for each of divided frequencies of the frequency signal, an nth order polynomial (n is a natural number) as a polynomial for interpolating sampling points and acquires a coefficient pattern including a set of values of coefficients of respective orders of the polynomial; a matching-data storing unit that stores, in association with the divided frequencies, matching data indicating a matching range as a range of a coefficient pattern regarded as noise; and a noise determining unit that determines, on the basis of a result obtained by comparing the coefficient pattern acquired by the patterning unit and the matching range indicated by the matching data, at least presence or absence of noise occurrence at a divided frequency corresponding to data of the compared coefficient pattern. |
| Inventors: |
OZAWA, Kazuhiko (Kanagawa, JP) |
| Assignees: |
Sony Corporation (Tokyo, JP) |
| Claim: |
1. A noise reducing device comprising: a sound-signal input unit that inputs a sound signal; a time-to-frequency converting unit that converts the input sound signal obtained by being input by the sound-signal input unit into a frequency signal; a patterning unit that calculates, for each of divided frequencies of the frequency signal, an nth order polynomial (n is a natural number) as a polynomial for interpolating sampling points and acquires a coefficient pattern including a set of values of coefficients of respective orders of the polynomial; a matching-data storing unit that stores, in association with the divided frequencies, matching data indicating a matching range as a range of a coefficient pattern regarded as noise; and a noise determining unit that determines, on the basis of a result obtained by comparing the coefficient pattern acquired by the patterning unit and the matching range indicated by the matching data, at least presence or absence of noise occurrence at a divided frequency corresponding to data of the compared coefficient pattern. |
| Claim: |
2. A noise reducing device according to claim 1, wherein the patterning unit executes, concerning the polynomial, normalization corresponding to a time direction such that an x coordinate value at an extreme value of the polynomial is 0. |
| Claim: |
3. A noise reducing device according to claim 2, wherein the patterning unit executes, concerning the polynomial, normalization corresponding to an amplitude direction such that a y coordinate value as an extreme value of the polynomial is an integer value. |
| Claim: |
4. A noise reducing device according to any one of claims 1 to 3, wherein the noise determining unit calculates, according to determination that noise is present, on a curve of the polynomial, a first tangent passing an x coordinate having a value smaller than an x coordinate at an extreme value and a second tangent passing an x coordinate having a value larger than the x coordinate at the extreme value, sets, as a noise occurrence start point, time corresponding to an x coordinate value at the time when the first tangent crosses a y coordinate value set as a threshold, and sets, as a noise occurrence end point, time corresponding to an x coordinate value at the time when the second tangent crosses the y coordinate value set as the threshold. |
| Claim: |
5. A noise reducing device according to any one of claims 1 to 4, further comprising a peak determining unit that determines, from the frequency signal, a sampling point at which amplitude of the frequency signal is at a peak, wherein the polynomial calculating unit calculates the polynomial for a divided frequency at which the sampling point is determined as having the peak by the peak determining unit. |
| Claim: |
6. A noise reducing device according to claim 5, wherein the peak determining unit maps absolute amplitudes of the sampling points as the frequency signal in a two-dimensional direction including a frequency axis and a time axis and determines the sampling point at the peak on the basis of a distribution state of the mapped absolute amplitudes. |
| Claim: |
7. A noise reducing device according to any one of claims 1 to 6, wherein the matching-data storing unit stores the matching data in association with a divided frequency corresponding to only a frequency band in which noise is determined as occurring. |
| Claim: |
8. A noise reducing device according to any one of claims 1 to 7, further comprising: a noise-removing filter unit that sets a pass band characteristic for interrupting only a divided frequency at which noise is determined as present by the noise determining unit and allows the input sound signal to pass to thereby output a sound signal from which noise is removed; an interpolation-signal generation unit that generates an interpolation signal including only a band component of the divided frequency at which noise is determined as present by the noise determining unit; and a combining unit that outputs a sound signal obtained by combining the sound signal from which noise is removed and the interpolation signal. |
| Claim: |
9. A noise reducing device according to any one of claims 1 to 8, wherein the interpolation-signal generating unit includes: an original-interpolation-signal generating unit that extracts, from the input sound signal, a pre-sound signal in a section before a noise occurrence period, which is recognized on a determination result of the noise determining unit, on a time axis and a post-sound signal in a section after the noise occurrence period on the time axis and connects the post-sound signal behind the pre-sound signal to thereby generate an original interpolation signal having time width corresponding to the noise occurrence period; and an interpolation filter unit that sets a pass band characteristic for allowing only a divided frequency at which noise is determined as present by the noise determining unit to pass to thereby generate the interpolation signal. |
| Claim: |
10. A noise reducing device according to claim 9, wherein the original-interpolation-signal generating unit extracts the pre-sound signal in time width from a start point of a noise occurrence period recognized on the basis of a determination result of the noise determining unit to a peak point when amplitude is at a peak in the noise occurrence period and extracts the post-sound signal in time width from the peak point to an end point of the noise occurrence period recognized on the basis of the determination result of the noise determining unit. |
| Claim: |
11. A noise reducing device according to any one of claims 1 to 8, wherein the interpolation-signal generating unit includes an interpolation filter that extracts, from the input sound signal, a pre-sound signal having time width for a noise occurrence period in a section before the noise occurrence period, which is recognized on the basis of a determination result of the noise determining unit, on a time axis or a post-sound signal having the time width for the noise occurrence period in a section after the noise occurrence period on the time axis and sets the pre-sound signal and the post-sound signal as an original interpolation signal, sets a pass band characteristic for allowing only a divided frequency at which noise is determined as present by the noise determining unit to pass, and allows the original interpolation signal to pass to thereby generate the interpolation signal. |
| Claim: |
12. A noise reducing device according to claim 8, wherein the interpolation-signal generating unit includes: an interpolation-signal-source generating unit that generates an interpolation signal source as a sound signal not based on the input of the input sound signal; and an interpolation filter unit that sets a pass band characteristic for allowing only a divided frequency at which noise is determined as present by the noise determining unit to pass and allows a sound signal as the interpolation signal source to pass to thereby generate the interpolation signal. |
| Claim: |
13. A noise reducing device according to any one of claims 1 to 12, further comprising a correlation-degree calculating unit that calculates a correlation degree between a pattern of the frequency signal and a pattern of a frequency signal treated as noise, wherein the noise determining unit determines at least presence or absence of the noise occurrence on the basis of a result obtained by comparing the coefficient pattern data acquired by patterning unit and the matching range indicated by the matching data and the correlation degree. |
| Claim: |
14. A noise reducing device according to any one of claims 1 to 13, further comprising a switching unit that receives input of a sound signal output from a combining unit and the input sound signal, outputs the sound signal output from the combining unit in a noise occurrence period recognized on the basis of a determination result of the noise determining unit, and outputs the input sound signal in a noise non-occurrence period recognized on the basis of a determination result of the noise determining unit. |
| Claim: |
15. A noise reducing device according to claim 14, wherein the switching unit executes cross-fade processing such that, in a start period in the noise occurrence period, a level of the sound signal output from the combining unit is gradually increased and a level of the input sound signal is gradually attenuated and, in an end period in the noise occurrence period, the level of the sound signal output from the combining unit is gradually attenuated and the level of the input sound signal is gradually increased. |
| Claim: |
16. A noise determining method comprising the steps of: inputting a sound signal; converting the input sound signal obtained by being input in the inputting step into a frequency signal; calculating, for each of divided frequencies of the frequency signal, an nth order polynomial (n is a natural number) as a polynomial for interpolating sampling points and acquiring a coefficient pattern including a set of values of coefficients of respective orders of the polynomial; storing, in association with the divided frequencies, matching data indicating a matching range as a range of a coefficient pattern regarded as noise; and determining, on the basis of a result obtained by comparing the coefficient pattern acquired in the patterning step and the matching range indicated by the matching data, at least presence or absence of noise occurrence at a divided frequency corresponding to data of the compared coefficient pattern. |
| Current U.S. Class: |
381/943 |
| Current International Class: |
04 |
| رقم الانضمام: |
edspap.20100260353 |
| قاعدة البيانات: |
USPTO Patent Applications |