JP4903665B2 - Howling prevention device, howling prevention program, and recording medium recording this program - Google Patents

Description

The present invention is a howling prevention method applied to an electroacoustic conversion reproduction device, and amplifies an acoustic input signal such as a hearing aid, a loudspeaker, or a karaoke device and outputs the amplified signal from a speaker or an earphone, that is, a microphone speaker (earphone) The present invention relates to a method, an apparatus, a program, and a recording medium for preventing howling of an apparatus system arranged in the vicinity.

In recent years, hearing aids have been reduced in size and increased in output, and a microphone part for inputting sound and an earphone part for outputting sound are arranged very close to each other. Similarly, in a loudspeaker, a high output speaker may be placed close to the microphone.

However, in these devices in which a speaker or an earphone is disposed close to the microphone, a part of the output signal from the speaker or the earphone is fed back to the microphone. At this time, the sound output signal is attenuated before reaching the microphone, but if the amount of amplification (G) of the device is larger than this amount of attenuation (L), feedback is repeated and the signal level increases infinitely. It will cause howling. The howling phenomenon not only produces unpleasant sounds, but also causes problems such as overuse of speakers and earphones and consumption of unnecessary power.

In order to prevent this howling, whether or not howling has occurred and the frequency at which howling has occurred are automatically estimated, and the frequency component is canceled by an antiphase signal, or near that frequency. Various methods such as a method of selectively reducing the amplification factor (Japanese Patent Laid-Open No. 6-22397), a method of modulating the phase of a signal, and a method of changing a delay time have been proposed (Japanese Patent Laid-Open No. 2000-341707; Kaihei 3-263999, JP 9-168195).

JP-A-6-22397

JP2000-341707

JP 3-263999

JP 9-168195 A

However, in the conventional system, it is extremely difficult to reliably and automatically estimate the presence or absence of howling and the frequency at which howling occurs, and the desired quality and volume cannot be obtained by a method of selectively reducing the amplification factor of a specific frequency. Phase modulation and frequency modulation prevent constant howling, but change the sound quality, and oscillation and cancellation are repeated alternately, resulting in annoying sound quality and further reducing the sound pressure to prevent howling. May result in an uncomfortable playback sound.

In view of the above-described problems, an object of the present invention is to provide a howling prevention device capable of preventing the occurrence of howling and reproducing sound without a sense of incongruity.

In order to solve the above-mentioned problems, the present inventors have taken the following measures as a result of intensive studies. That is, the specific frequency part extracting means for extracting the sound signal of the specific frequency part of the input sound signal, dividing the extracted sound signal into three or more frequency components, and calculating the average value of the sound pressure of each frequency component Sound pressure average value calculating means, sound pressure difference calculating means for calculating the difference between the sound pressure of each frequency component described above and the average value of the calculated sound pressure, whether the sound pressure difference is equal to or greater than a reference value during a reference time A judgment means for judging whether or not, when the judgment means judges that the sound pressure difference is equal to or greater than a reference value, the sound pressure in a frequency band in which the difference from the average value of the frequency is equal to or greater than the reference value is used as the average sound pressure. A sound pressure adjusting means for lowering may be provided.

The specific frequency may be 1000 Hz to 4000 Hz, and the reference value may be 10 dB. The reference time may be 0.05 seconds to 0.5 seconds.

  Next, other cases will be described. Specific frequency portion extraction means for extracting an acoustic signal of a specific frequency portion of the input acoustic signal, dividing the extracted acoustic signal into three or more frequency components, and calculating the peak value of the sound pressure of each frequency component described above Peak value calculating means, sound pressure average value calculating means for calculating the average value of the sound pressure of each frequency component, peak value sound pressure average value calculating means for calculating the average value of each of the aforementioned peak value sound pressures, Peak value sound pressure difference calculating means for calculating the difference between the peak value sound pressure of the frequency component and the average value of the calculated peak value sound pressure, whether the above peak value sound pressure difference is equal to or greater than the reference value during the reference time The sound pressure in the frequency band in which the difference from the sound pressure peak average value of the frequency is equal to or greater than the reference value when the peak sound pressure difference is determined to be greater than or equal to the reference value by the determination means. Sound pressure adjustment to lower the average sound pressure It is sufficient to provide a stage.

The specific frequency may be 1000 Hz to 4000 Hz, and the reference value may be 10 dB. The reference time may be 0.05 seconds to 0.5 seconds.

Still another method will be described. Specific frequency portion extraction means for extracting an acoustic signal of a specific frequency portion of the input acoustic signal, dividing the extracted acoustic signal into three or more frequency components, and calculating the average value of the sound pressure of each frequency component described above Sound pressure average value calculation means, sound pressure difference calculation means for calculating the difference between the sound pressure of each frequency component described above and the average value of the calculated sound pressure, and whether or not the sound pressure difference is greater than a reference value. Judgment means for judging, providing a howling frequency band excluded sound pressure average value calculating means for calculating the average value of the sound pressure of each frequency band excluding the sound pressure of the frequency band in which the sound pressure difference is determined to be equal to or greater than a reference value, When the sound pressure difference is determined to be greater than or equal to the reference value by the determining means, the sound pressure in the frequency band in which the difference from the average value of the frequency is equal to or greater than the reference value for the reference time is the sounding frequency band excluded sound pressure average. Calculated by the value calculating means The sound pressure adjusting means for reducing the cowling frequency band excluding sound pressure average neon pressure may if provided.

The specific frequency may be 1000 Hz to 4000 Hz, and the reference value may be 10 dB. The reference time may be 0.05 seconds to 0.5 seconds.

Still another case will be described. Specific frequency portion extraction means for extracting an acoustic signal of a specific frequency portion of the input acoustic signal, dividing the extracted acoustic signal into three or more frequency components, and calculating the peak value of the sound pressure of each frequency component described above Peak value calculating means, sound pressure average value calculating means for calculating the average value of the sound pressure of each frequency component, peak value sound pressure average value calculating means for calculating the average value of each peak value sound pressure, The peak value sound pressure difference calculating means for calculating the difference between the peak value sound pressure of each frequency component and the average value of the calculated peak value sound pressure, whether the aforementioned peak value sound pressure difference is equal to or greater than the reference value during the reference time Judgment means for judging whether or not, howling frequency band excluded sound pressure average calculation for calculating the average value of the sound pressure of each frequency band excluding the sound pressure of the frequency band in which the above-mentioned peak value sound pressure difference is determined to be greater than or equal to the reference value Means for determining When the peak sound pressure difference is determined to be greater than or equal to the reference value, the sound pressure in the frequency band in which the difference from the peak sound pressure average value of the frequency is greater than or equal to the reference value is calculated by the howling frequency band excluded sound pressure average value calculation means. It is only necessary to provide sound pressure adjusting means for reducing the calculated howling frequency band excluded sound pressure to the average sound pressure value.

The specific frequency may be 1000 Hz to 4000 Hz, and the reference value may be 10 dB. The reference time may be 0.05 seconds to 0.5 seconds.

In each of the above methods, the program may be described in a program language readable by a computer, and may be configured by a computer-readable recording medium.

As described above, according to the present invention, particularly howling that is highly likely to be performed by a hearing aid or the like is taken out and analyzed to discriminate and detect howling from human voices and other sounds, and to prevent conventional howling. Without compressing the sound pressure that makes the original voice feel uncomfortable with the part of the howling frequency as shown in FIG. By setting the sound pressure of the howling portion to the average value of the sound pressure of the sound pressure frequency portion including the howling portion, it is possible to reproduce howling-preventing sound without a sense of incompatibility.

This is because a person's conversational sound pressure rarely continues, and by separating time, it becomes possible to distinguish a person's voice and howling. In particular, in a hearing aid or the like, the howling frequency is generated from 1000 Hz to 4000 Hz. Therefore, it is possible to efficiently use the apparatus by omitting monitoring of other frequency portions and observing only this portion (1000 Hz to 4000 Hz).

  This will be specifically described below with reference to the drawings.

FIG. 1 is a schematic block diagram showing a first embodiment of the present invention. The input sound is converted from analog to digital by 101 AD conversion means, and a frequency extraction and division means for extracting a frequency band from 1000 Hz to 4000 Hz at 102 and further dividing it into 10 parts. Then, the calculation of the average value of the sound pressures of the respective portions divided into 10 is performed by the respective frequency sound pressure average calculating means portions of 103. Then, the calculation result is registered in the data storage unit 104. Next, at 105, the difference between the sound pressures in each region and the average value of the sound pressures is calculated to determine whether the sound pressure difference in this part is 10 dB or more and this state continues for 0.3 seconds or more, and the sound pressure difference is continuously 10 dB or more. When it is 0.3 seconds or more, it is determined that howling.

A schematic diagram of this state is shown in FIG. 3. Here, it is the input signal 301 that has caused howling, and each of 10 of A, B, C, D, E, F, G, H, I, J is shown. Divide into parts and calculate the average value of sound pressure. The calculation result is 302 lines, and the respective sound pressure differences are calculated. Here, the area B calculates the difference 303 between 301 and 302, and similarly calculates the difference 304 between 301 and 302 in the area F. is doing.

Next, if there is a portion determined to be howling by the howling unit sound pressure setting means 106, the sound pressure average value data of the data storage unit 104 is read as the sound pressure of the frequency portion, and the read sound pressure is read as the frequency portion. Set as the sound pressure. Then, the sound pressure is set to the sound pressure average value only in this howling frequency portion, and the other portion may be converted from analog to digital by the AD conversion means 107 and output.

FIG. 2 shows the flow at that time. In 201, the frequency portion from 1000 Hz to 4000 Hz is extracted from the input signal, and then in 1000, the portion from 1000 Hz to 4000 Hz is divided into 10. The average value of the sound pressure of each part divided into 10 in 203 is calculated, and the difference between the sound pressure of each part and the average value is calculated in 204. In 205, it is determined whether the sound pressure difference between each part and the average value is 10 dB or more and this state continues for 0.3 seconds or more.

If the sound pressure difference between each part and the average value is 10 dB or more and this state continues for 0.3 seconds or more, the corresponding frequency is determined as a howling frequency in 206, and the sound pressure in the corresponding frequency (howling frequency) is averaged in 207. Set to.

FIG. 4 is a schematic block diagram showing a second embodiment of the present invention. The input voice is converted from analog to digital by an AD conversion means 401, a frequency extraction and division means for extracting a frequency band from 1000 Hz to 4000 Hz at 402 and further dividing it into 10 parts. Then, the peak value of each sound pressure of each part divided into 10 is detected, and the average value of the peak sound pressure is calculated in each frequency peak sound pressure average calculating means part 403. The calculation result is registered in the data storage unit 404. Next, at 405, the difference between the peak sound pressure of each region and the average value of the peak sound pressure is calculated to determine whether the sound pressure difference in this portion is 10 dB or more and this state continues for 0.3 seconds or more, and the sound pressure difference is 10 dB. When it is continuously 0.3 seconds or more, it is determined that howling.

A schematic diagram of this state is shown in FIG. 6. Here, it is an input signal 601 that causes howling, and each of 10 of A, B, C, D, E, F, G, H, I, and J is shown. Dividing into parts, the peak sound pressure of each part is detected as a, b, c, d, e, f, g, h, i, j, and the average value of the peak sound pressure is calculated. The calculation result is a line of 602, and each sound pressure difference is calculated. Here, the region B calculates the difference 603 between b and 602, and similarly calculates the difference 604 between f and 602 in the region F. is doing.

Next, at 406, the average value of the sound pressure at each frequency is calculated, and the result is registered in the data storage means 407. Next, if there is a portion determined to be howling by the howling unit sound pressure setting means 408, the sound pressure at the frequency portion is read out as the sound pressure average value data of the data storage unit 407, and the read sound pressure is read as the frequency portion. Set as the sound pressure. Then, the sound pressure is set to the sound pressure average value only in this howling frequency portion, and the other portion may be digital-analog converted and output from the input digital signal by the 409 DA conversion means.

FIG. 5 shows the flow at that time. In 501, the frequency portion from 1000 Hz to 4000 Hz is extracted from the input signal, and in 502, the portion from 1000 Hz to 4000 Hz is divided into 10. In 503, the peak sound pressure of each part is calculated. In 504, the average value of the peak sound pressure of each part divided into 10 is calculated. In 505, the difference between the sound pressure of each part and the average value is calculated. In 506, it is determined whether the sound pressure difference between each part and the average value is 10 dB or more and this state continues for 0.3 seconds or more.

If the sound pressure difference between each part and the average value is 10 dB or more and this state continues for 0.3 seconds or more, the corresponding frequency is determined as the howling frequency in 507, the average value of the sound pressure in each part is calculated in 508, and in 509 The sound pressure at the frequency (howling frequency) part is set to an average value.

FIG. 7 is a schematic block diagram showing a third embodiment of the present invention. The input voice is converted from analog to digital by the AD conversion means 701, the frequency band 1000Hz to 4000Hz is extracted in the portion 702, and further divided into 10 portions. Then, the calculation of the average value of the sound pressures of the respective parts divided into 10 is performed by the respective frequency sound pressure average calculating means parts 703. The calculation result is registered in the data storage unit 704. Next, in 705, the difference between the sound pressures in each region and the average value of the sound pressures is calculated to determine whether the sound pressure difference in this part is 10 dB or more and this state continues for 0.3 seconds or more, and the sound pressure difference is continuously 10 dB or more. When it is 0.3 seconds or more, it is determined that howling.

A schematic diagram of this state is shown in FIG. 9. Here, it is an input signal 901 that has caused howling, and each of A, B, C, D, E, F, G, H, I, and J is shown in FIG. Divide into parts and calculate the average value of sound pressure. The calculation result is a line of 902, and the respective sound pressure differences are calculated. Here, the area B calculates the difference 903 between 901 and 902, and similarly calculates the difference 904 between 901 and 902 in the area F. is doing.

Next, in 705, the average value of the sound pressures of the respective frequency parts of the nine frequency parts excluding the howling frequency part is calculated, and the result is registered in the data storage means 707. Next, if there is a portion determined as howling by the howling unit sound pressure setting means 708, the sound pressure average value data of the data storage unit 707 is read as the sound pressure of the frequency portion, and the read sound pressure is read as the frequency portion. Set as the sound pressure. Then, the sound pressure is set to the sound pressure average value obtained by omitting the howling frequency portion only in this howling frequency portion, and the other portion may be digital-analog converted by the 709 DA conversion means and output.

FIG. 8 shows the flow at that time. At 801, the frequency portion from 1000 Hz to 4000 Hz is extracted from the input signal, and then the portion from 1000 Hz to 4000 Hz is divided into 10 at 802. In 803, the frequency is divided into 10, and the average value of each frequency portion is calculated. In 805, it is determined whether the sound pressure difference between each part and the average value is 10 dB or more and this state continues for 0.3 seconds or more.

If the sound pressure difference between each part and the average value is 10 dB or more and this state continues for 0.3 seconds or more, the corresponding frequency is determined as the howling frequency in 806, and the average value excluding the howling frequency is calculated in 807. In 808, the sound pressure of the corresponding frequency (howling frequency) is set to an average value excluding the howling frequency.

FIG. 10 is a schematic block diagram showing a fourth embodiment of the present invention. The input voice is converted from analog to digital by 1001 AD conversion means, the frequency band 1000 Hz to 4000 Hz is extracted at 1002 part, and further divided into 10 parts. Then, the peak sound pressure of each part divided into 10 is calculated, and the average value of the peak sound pressure is calculated in each frequency peak sound pressure average calculating means part 1003. The calculation result is registered in the data storage unit 1004. Next, at 1005, the difference between the peak sound pressure of each region and the average value of the peak sound pressure is calculated to determine whether the sound pressure difference in this portion is 10 dB or more and this state continues for 0.3 seconds or more, and the sound pressure difference is 10 dB. When it is continuously 0.3 seconds or more, it is determined that howling.

A schematic diagram of this state is shown in FIG. 12. Here, it is an input signal 1201 that causes howling, and each of 10 of A, B, C, D, E, F, G, H, I, and J is shown. Dividing into parts, the peak sound pressure of each part is detected as a, b, c, d, e, f, g, h, i, j, and the average value of the peak sound pressure is calculated. The calculation result is a line of 1202, and each sound pressure difference is calculated. Here, the region B calculates the difference 1203 between b and 1202, and similarly calculates the difference 1204 between f and 1202 in the region F. is doing.

Next, in 1005, the average value of the sound pressures of the respective frequency parts of the nine frequency parts excluding the howling frequency part is calculated, and the result is registered in the data storage means 1007. Next, if there is a portion determined as howling by the howling unit sound pressure setting unit 1008, the sound pressure average value data of the data storage unit 1007 is read as the sound pressure of the frequency portion, and the read sound pressure is read as the frequency portion. Set as the sound pressure. Then, the sound pressure of only the howling frequency part is set to the sound pressure average value excluding the howling frequency part, and the other part may be digital-analog converted by a DA converter means 1009 and output as it is.

FIG. 11 shows the flow at that time. In 1101, the frequency portion from 1000 Hz to 4000 Hz is extracted from the input signal, and then in 1102, the portion from 1000 Hz to 4000 Hz is divided into 10. In 1103, the peak sound pressure of each part is calculated. In 1104, the average value of the peak sound pressure of each part divided into 10 is calculated. In 1105, the difference between the sound pressure of each part and the average value is calculated. In 1106, it is determined whether the sound pressure difference between each part and the average value is 10 dB or more and this state continues for 0.3 seconds or more.

If the sound pressure difference between each part and the average value is 10 dB or more and this state continues for 0.3 seconds or more, the corresponding frequency is determined as the howling frequency in 1107, and the average value of the sound pressures in each part excluding the howling frequency part is obtained in 1108. In operation 1109, the sound pressure of the corresponding frequency (howling frequency) is set to an average value.

Schematic block diagram of the first embodiment Flow of the first embodiment Schematic diagram of the first embodiment Schematic block diagram of the second embodiment Flow of the second embodiment Schematic diagram of the second embodiment Schematic block diagram of the third embodiment Flow of the third embodiment Schematic diagram of the third embodiment Schematic block diagram of the fourth embodiment Flow of the fourth embodiment Schematic diagram of the fourth embodiment

Claims (10)

Specific frequency portion extraction means for extracting an acoustic signal of a specific frequency portion of the input acoustic signal, a sound for dividing the extracted acoustic signal into three or more frequency components and calculating an average value of sound pressures of the respective frequency components Pressure average value calculating means, sound pressure difference calculating means for calculating the difference between the sound pressure of each frequency component and the calculated average value of the sound pressure, determining means for determining whether the sound pressure difference is greater than or equal to a reference value, Provided is a howling frequency band excluded sound pressure average value calculating means for calculating an average value of sound pressures in each frequency band excluding sound pressure in a frequency band in which the sound pressure difference is determined to be equal to or greater than a reference value, and the sound pressure difference is determined by the determining means. The howling obtained by calculating the sound pressure in the frequency band in which the difference from the average value of the frequency is equal to or greater than the reference value during the reference time when the sound frequency is determined to be equal to or greater than the reference value by the howling frequency band excluded sound pressure average value calculating means Frequency band exclusion Prevention device of howling, characterized in that it has a sound pressure adjusting means for reducing the sound pressure average neon pressure. 2. The howling prevention apparatus according to claim 1, wherein the specific frequency is 1000 Hz to 4000 Hz . 2. The howling prevention apparatus according to claim 1 , wherein the reference value is 10 dB . 2. The howling prevention apparatus according to claim 1, wherein the reference time is 0.05 seconds to 0.5 seconds . Specific frequency portion extraction means for extracting an acoustic signal of a specific frequency portion of the input acoustic signal, a peak for dividing the extracted acoustic signal into three or more frequency components, and calculating a peak value of sound pressure of each frequency component Value calculating means, sound pressure average value calculating means for calculating the average value of the sound pressure of each frequency component, peak value sound pressure average value calculating means for calculating the average value of each peak value sound pressure, Peak value sound pressure difference calculating means for calculating the difference between the peak value sound pressure and the average value of the calculated peak value sound pressure, and determining means for determining whether the peak value sound pressure difference is equal to or greater than a reference value during a reference time. A sounding frequency band excluded sound pressure average value calculating means for calculating an average value of sound pressures in each frequency band excluding a sound pressure in a frequency band in which the peak value sound pressure difference is determined to be equal to or greater than a reference value; peak value of the sound pressure by The howling There computed by the frequency of the peak value the sound pressure average value and the sound pressure howling frequency band excluding noise of a frequency band difference is greater than or equal to the reference value of the pressure average value calculating means when it is determined that the reference value or more A sounding prevention device comprising a sound pressure adjusting means for reducing the frequency band excluded sound pressure to an average sound pressure . 6. The howling prevention apparatus according to claim 5, wherein the specific frequency is 1000 Hz to 4000 Hz . 6. The howling prevention apparatus according to claim 5 , wherein the reference value is 10 dB . 6. The howling prevention apparatus according to claim 5, wherein the reference time is 0.05 seconds to 0.5 seconds . Computer is described by a readable programming language, howling prevention program for executing a device for preventing howling according to any one of claims the first to 8 wherein the computer. A recording medium comprising a computer-readable recording medium, wherein the howling prevention program according to claim 9 is recorded on the recording medium.

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