JP5645373B2 - Audio processing apparatus and audio processing method - Google Patents

Description

  The present invention relates to an audio signal processing apparatus, and more particularly to an apparatus that can reduce wind noise (window noise) included in an acquired audio signal.

  2. Description of the Related Art Conventionally, as an apparatus that processes an audio signal, an imaging apparatus that records an image signal and an audio signal is known. These image pickup apparatuses include a microphone for collecting external sound and generating a sound signal. However, when wind strikes the periphery of the image pickup apparatus, noise (wind noise) that is annoying to the user is generated. There was a thing.

  In order to solve such a problem, a technique of attenuating a low frequency component having a large influence of wind noise by using a low-pass filter that attenuates, for example, a low frequency component of 100 kHz or less of a voice input from a microphone has been proposed. For example, as in the technique of Patent Document 1, after reducing wind noise, an audio level is adjusted by an auto level controller (hereinafter ALC). The ALC amplifies the audio signal when the audio level is low, and attenuates the audio signal when the audio level is high.

JP 05-328480 A

  However, in reality, when the wind noise component is included in a frequency that cannot be attenuated, it is difficult to completely eliminate the wind noise, and the noise component may remain in the audio signal. For this reason, when the level of sound other than wind noise is low, the sound signal containing wind noise is amplified, making it difficult to hear.

  Therefore, the present invention provides an audio signal processing device that can reduce the possibility of amplifying wind noise components included in an audio signal by limiting the upper limit value of the ALC amplification factor when the air volume is large. The purpose is to provide. Here, when the air volume is large, it is when there are many wind noise components included in the audio signal.

  In order to achieve the above object, the sound processing apparatus of the present invention has a plurality of sound collecting means and a processing means for processing sound signals obtained by the plurality of sound collecting means. Amplifying the sound signal obtained by the sound collecting means with an amplification factor corresponding to the level of the sound signal obtained by the sound collecting means and not larger than a predetermined gain; The predetermined amplification factor is reduced as the magnitude of noise caused by wind included in the audio signal obtained by the means increases.

  According to the present invention, it is possible to reduce the possibility that the wind noise component included in the audio signal is amplified when the air volume is large, and to obtain the audio signal in which the wind noise component that is unpleasant to the user is not amplified. be able to.

1 is a block diagram of an imaging apparatus according to Embodiments 1 and 2. FIG. 3 is a block diagram of a voice input unit 102 according to Embodiment 1. FIG. It is a figure which shows the relationship between the amplitude level of the audio | voice signal of Example 1, 2 and the amplification factor with respect to an audio | voice signal. 6 is a block diagram of a voice input unit 102 according to Embodiment 2. FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  An imaging apparatus capable of processing and recording an audio signal will be described.

  FIG. 1 is a block diagram illustrating the configuration of the imaging apparatus according to the first embodiment.

  In FIG. 1, reference numeral 100 denotes an imaging apparatus main body. Reference numeral 101 denotes an imaging unit that captures a subject image and obtains an image signal. An audio input unit 102 collects audio around the imaging apparatus 100 with a microphone, performs analog-digital conversion, wind noise removal processing (to be described later), amplitude control (level control) of an audio signal, and the like, and generates an audio signal It is. Reference numeral 103 denotes a memory for temporarily storing the image signal obtained by the imaging unit 101 and the audio signal obtained by the audio input unit 102. Reference numeral 104 denotes a display control unit that causes the display unit 105 to display a video related to an image signal obtained by the imaging unit 101, an operation screen of the imaging device 100, a menu screen, and the like. Reference numeral 106 denotes an encoding processing unit that reads out image signals and audio signals temporarily stored in the memory 103 and performs predetermined encoding to generate compressed image signals, compressed audio signals, and the like. 107 records the compressed image signal, the compressed audio signal, and the like generated by the encoding processing unit 106 on the recording medium 108, or the compressed image signal, the compressed audio signal, various data recorded on the recording medium 108, A recording / reproducing unit that reads a program. Reference numeral 109 denotes a control unit for controlling each block of the imaging apparatus 100. Reference numeral 110 denotes an operation unit for inputting an instruction from the user. Reference numeral 111 denotes an audio output unit that outputs a compressed audio signal reproduced by the recording / reproducing unit 107 and an audio signal output from the control unit 109. Reference numeral 112 denotes a speaker that outputs the audio signal output from the audio output unit 111 as audio. Reference numeral 113 denotes an external output unit for outputting video or audio reproduced by the recording / reproducing unit 107 to an external device. A data bus 114 supplies various data such as audio signals and image signals and control signals to each block of the imaging apparatus 100.

  Here, the operation at the time of moving image shooting of the imaging apparatus 100 of the present embodiment will be described.

  In response to the operation of the power switch of the operation unit 110, the imaging apparatus 100 shifts to a shooting standby state. In this state, when the user operates the shooting start button of the operation unit 110, the control unit 109 transmits a shooting start signal to the imaging unit 101, the audio input unit 102, the encoding processing unit 106, the recording / playback unit 107, and the like. To start.

  When shooting starts, the imaging unit 101 obtains an image signal by converting the optical image of the subject captured by the shooting lens into an electrical signal by the imaging element. The control unit 109 temporarily stores the image signal obtained by the imaging unit 101 in the memory 103, and the encoding processing unit 106 encodes the image signal stored in the memory to generate a compressed image signal.

  On the other hand, the voice input unit 102 collects surrounding sounds with a microphone, performs wind noise removal processing described later, amplitude control (level control) of the voice signal, and the like to obtain a voice signal. The control unit 109 temporarily stores the audio signal obtained by the audio input unit 102 in the memory 103. The encoding processing unit 106 encodes the audio signal stored in the memory and generates a compressed audio signal.

  Then, the control unit 109 synthesizes the compressed image signal and the compressed audio signal to form a data stream, and outputs the data stream to the recording / reproducing unit 107. Based on an instruction from the control unit 109, the recording / playback unit 107 writes the data stream as one moving image file on the recording medium 108 under the management of a file system such as UDF or FAT. During shooting, an image signal obtained by the imaging unit 101 is transmitted to the display control unit 104 and displayed on the display unit 105 as necessary.

  Here, when the user operates the shooting end button of the operation unit 110, the control unit 109 transmits a shooting end signal to the imaging unit 101, the audio input unit 102, the encoding processing unit 106, the recording / playback unit 107, and the like. Terminate. When the imaging end signal is received, the imaging unit 101 and the audio input unit 102 stop generating the image signal and the audio signal. The recording / playback unit records the compressed image signal from the start to the end of shooting and the compressed image signal as one file on the recording medium 108 and then ends the recording operation.

  Then, the control unit 109 shifts the imaging device 100 to the shooting standby state again.

  In the present embodiment, when such moving image shooting is performed, the audio input unit 102 performs various processes when obtaining an audio signal.

  Therefore, an operation performed during moving image shooting in the voice input unit 102 will be described with reference to FIG.

  In FIG. 2, reference numeral 201 denotes a microphone unit that collects ambient sounds, converts them into electrical signals, and obtains audio signals. Reference numeral 202 denotes an A / D converter that converts an audio signal obtained by the microphone unit 201 from an analog signal to a digital signal. Reference numeral 203 denotes a stereo conversion unit 203 that converts an audio signal obtained by the microphone unit into a stereo signal. 204 is a wind noise removing unit for reducing noise (wind noise) caused by wind of a low frequency component (for example, a variable frequency of 20 Hz to 200 Hz or less) generated when wind is blowing around. It is. 205L / 205R is an auto level controller (hereinafter, ALC) for keeping the level of the audio signal at an appropriate level. In 205L / 205R, the amplification factor for the audio signal is increased when the level of the input audio signal is low, and the amplification factor is decreased when the level of the audio signal is high.

  The wind noise removing unit 204 indicates that the two audio signals obtained by the microphone unit have almost no phase difference in normal sound, and that there is a phase difference in low frequency components (for example, 100 Hz or less) particularly in wind noise. The wind noise is removed by using it. For this purpose, processing is performed on stereo audio Lch and Rch audio obtained by the stereo conversion unit 203.

  Specifically, first, the subtractor 206 outputs an Lch-Rch signal (difference signal). When there is no wind noise, the value of the difference signal is small, and when there is a lot of wind noise, the absolute value of the difference signal is large. In the present embodiment, the air volume detector 207 detects the air volume (wind intensity, wind speed, wind pressure, or the amount and magnitude of noise caused by wind) based on the value of the difference signal. . In the air volume detection unit 207, if the absolute value of the difference signal is large, a signal indicating that the air volume is large (the noise due to the wind is large or large), and if the difference signal value is small, the air volume is small (the noise due to the wind is small or small). ) The signal shown is output as air volume information. This utilizes the property that the phase difference between two audio signals becomes large in the low frequency component (for example, 100 Hz or less) when there is wind noise. Further, in a situation where no wind is blowing, if the value of the difference signal is extremely small, the air volume information is not output. In this embodiment, for the sake of explanation, a case where the air volume is large (the noise due to the wind is large or large), the air volume is small (the noise due to the wind is small or small), and the case where there is no air volume will be described. However, as a matter of course, three or more types of airflow information values may be output according to the absolute value of the difference signal output by the subtracting unit 206.

  Subsequently, the signal is input to a high-pass filter (HPF) 208 for attenuating the low-frequency component of the difference signal output by the subtracting unit 206, and a signal obtained by attenuating the low-frequency component signal of the difference signal is output. The HPF 208 sets the cutoff frequency of the low frequency component to be attenuated to, for example, 200 Hz if the value of the air volume information detected by the air volume detecting unit 207 is large, and sets the cutoff frequency to 20 Hz if the value of the air volume information is small. Or, if the value of the air volume information is large, the attenuation amount of the low frequency component is increased, and if the value of the air volume information is small, the attenuation amount of the low frequency component is decreased. That is, the HPF 208 is configured to change the attenuation characteristic according to the value of the air volume information. As a matter of course, the HPF 208 may be configured by other filters such as a band pass filter instead of the high pass filter.

  The adder 209 adds or subtracts the signal obtained by attenuating the low-frequency component of the difference signal thus obtained with the Lch + Rch signal (sum signal), thereby obtaining Lch and Rch audio. it can.

  Specifically, the addition unit 210 adds the signal obtained by attenuating the low-frequency component of the difference signal and the sum signal, thereby reducing the Lch component having a phase difference between Lch and Rch in the low-frequency component. Audio signals are generated. Then, the subtracting unit 211 subtracts a signal obtained by attenuating the low frequency component of the difference signal from the sum signal, whereby an Rch audio signal in which a component having a different phase between Lch and Rch is reduced in the low frequency component. Generated. With this process, it is possible to generate Lch and Rch audio signals with reduced wind-induced noise (wind noise).

  Here, the ALC 205L will be further described.

  In the ALC 205L of the present embodiment, the amplification factor for the audio signal is increased when the level of the input audio signal is low, and the amplification factor is decreased when the level of the audio signal is high. Here, the Lch audio signal will be described, but the same processing is performed for the Rch audio signal.

  First, the operation when no wind noise occurs will be described.

  The Lch audio signal input to the ALC 205L is delayed for several ms by the delay unit 212, and the amplitude of the audio signal is amplified by the amplitude control unit 213. The amplification factor in the amplitude control unit 213 is determined according to the amplitude of the audio signal input to the ALC 205. For this purpose, the amplitude detection unit 214 detects the amplitude of the audio signal input to the ALC 205, and the amplification factor setting unit 215 amplifies the audio signal in the amplitude adjustment unit 213 according to the detected amplitude. Set the rate. The relationship between the amplitude level of the detected audio signal in the amplification factor setting unit 215 and the amplification factor of the audio signal in the amplitude adjustment unit 213 is as shown in FIG.

  In the amplification factor setting unit 215, when the amplitude of the audio signal detected by the amplitude detection unit 214 is larger than the threshold value X, the amplification factor of the audio signal is decreased, and the larger the amplitude of the audio signal is, the larger the audio signal amplitude is. Reduce the amplification factor. Specifically, the amplification factor of the audio signal is set to a value between the normal value Gnor and a smaller Glim (Gnor> Glim). When the amplitude of the audio signal is smaller than the threshold Y, the amplification factor of the audio signal is increased, and the amplification factor is increased as the amplitude of the audio signal is smaller (where X> Y). Specifically, the amplification factor of the audio signal is set to a value between the normal value Gnor and a larger Grec (Grec> Gnor). However, the amplification factor is an amplification factor that does not become larger than Grec. When the amplitude of the audio signal is other than that, the amplification factor of the audio signal is fixed to the normal value Gnor.

  With this configuration, the input audio signal is maintained at an appropriate level by the amplitude adjustment unit 213.

  Up to this point, the operation of the ALC 205 has been described when no wind noise is generated. Next, the operation when wind noise occurs will be described. In this embodiment, when the air volume information is received, the amplification factor setting unit 215 is controlled, and the ALC 205 is controlled so that the audio signal is not excessively amplified.

  The amplitude adjusting unit 213 of the present embodiment normally amplifies the audio signal when the level of the input audio signal is a predetermined value. However, when the air volume information is output by the air volume detector 207 (when the air volume is detected), the upper limit of the amplification factor is lowered. For example, as shown in FIG. 3B, when the value of the air volume information is small, the maximum value of the amplification factor in the amplitude adjustment unit 213 is set to GrecA smaller than Grec. That is, the gain is changed to a point where the amplification factor does not become larger than GrecA. Further, when the value of the air volume information is large, the maximum value of the amplification factor in the amplitude adjustment unit 213 is set to GrecB that is smaller than GrecA. That is, the gain is changed so that the amplification factor does not become larger than GrecB. Here, Grec> GrecA> GrecB.

  As described above, the amplification factor setting unit 215 sets the maximum value of the amplification factor in the amplitude adjustment unit 213 between Grec and Gnor according to the air volume. That is, control is performed so that the maximum value of the amplification factor in the amplitude adjustment unit 213 is brought closer to the normal value Gnor as the air volume is larger, and closer to Grec as the air volume is smaller.

  As described above, in this embodiment, when the wind is detected, the maximum value of the amplification factor in the amplitude adjustment unit 213 is reduced. More specifically, when the air volume is large, the maximum value of the amplification factor in the amplitude adjusting unit 213 is reduced more than when the air volume is small. In the present embodiment, the case where the air volume is small and the air volume is large has been described. However, even if the air volume information indicates other air volumes, the maximum value of the amplification factor is decreased as the air volume value increases. do it.

  By adopting such a configuration, the image pickup apparatus of the present embodiment can lower the maximum value of the amplification factor of the audio signal as the air volume increases. By doing so, it is possible to reduce the possibility of amplifying the wind noise component included in the audio signal when the air volume is large, and to obtain the audio signal that is not amplified by the user's annoying wind noise component Can do.

  Further, as in this embodiment, in the case of a method of reducing wind noise using the phase difference between audio signals input from two microphones, an audio signal having no phase difference (in-phase) is input. Wind noise may not be reduced. In this case, in particular, a configuration in which the maximum value of the amplification factor is made smaller as the airflow value is larger as in the present embodiment, so that it is possible to obtain an audio signal in which the annoying wind noise component is not amplified for the user. it can.

  In the present embodiment, the amplification factor setting unit 215 is controlled to reduce the maximum value of the amplification factor in the amplitude adjustment unit 213. However, for example, by changing the detection level in the amplitude detection unit 214 in accordance with the air volume, it is possible to control so as to reduce the maximum value of the amplification factor in the amplitude adjustment unit 213. That is, when the amplitude level detected by the amplitude detector 214 is Y or less, a predetermined amount of value is added to the detected amplitude level if wind is detected. Then, since the amplification factor setting unit 215 detects that the audio signal has a level equal to or higher than the detected amplitude level, the amplification factor in the amplitude adjustment unit 213 is controlled to be close to Gnor. Further, when the air volume is large, the value added to the detected amplitude level is increased compared to when the air volume is small. By doing in this way, it can also be controlled to reduce the maximum value of the amplification factor in the amplitude adjustment unit 213.

  In the present embodiment, the air volume is detected based on the difference signal between the two audio signals. However, the low frequency components of the two audio signals may be simply compared. Alternatively, the air volume may be detected using a unit capable of detecting air displacement such as a wind pressure sensor, an anemometer, or a device using a laser and a camera.

  In this embodiment, the image pickup apparatus has been described. However, the sound processing to the sound input unit 102 according to this embodiment may be any apparatus that records or inputs external sound and outputs the sound. Even a simple device can be applied. For example, you may apply to an IC recorder, a mobile telephone, etc.

  In the first embodiment, the case where the sound is 2ch has been described, but in the second embodiment, the processing of the sound input unit 102 at the time of moving image shooting in 5.1ch will be described with reference to FIG.

  In the present embodiment, blocks having the same functions as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The sound input unit 102 of the image pickup apparatus of the present embodiment includes a microphone unit 201A / 201B, an A / D conversion unit 202A / 202B, and a wind noise removal unit 204A / 204B in order to generate 5.1ch sound. . Then, the four audio signals output from the wind noise removing unit 204A / 204B are input to the 5.1ch processing unit 401. The 5.1ch processing unit 401 adds a calculation to the four input audio signals to generate a 5.1ch sound and inputs it to the ALC 205.

  On the other hand, the outputs of the air volume information 1 and the air volume information 2 detected by the respective wind noise removing sections 204 are input to the air volume comparing section 402, respectively. The air volume comparison unit 402 detects the larger value of the air volume information 1 and the air volume information 2 and inputs the detected value to the ALC 205. Also in the present embodiment, the air volume information can output three or more types of values according to the air volume.

  As in the first embodiment, the ALC 205 controls the amplification factor setting unit 215 in accordance with the input airflow value (the larger one of the airflow information 1 and the airflow information 2). It is controlled not to be amplified.

  When the wind is detected, the maximum value of the amplification factor in the amplitude adjustment unit 213 is reduced. More specifically, when the air volume is large, the maximum value of the amplification factor in the amplitude adjusting unit 213 is more greatly reduced than when the air volume is small.

  By adopting such a configuration, the image pickup apparatus of the present embodiment can lower the maximum value of the amplification factor of the audio signal as the air volume increases. By doing so, it is possible to reduce the possibility of amplifying the wind noise component included in the audio signal when the air volume is large, and to obtain the audio signal that is not amplified by the user's annoying wind noise component Can do.

  In the present embodiment, the amplification factor setting unit 215 is controlled to reduce the maximum value of the amplification factor in the amplitude adjustment unit 213. However, for example, by changing the detection level in the amplitude detection unit 214 in accordance with the air volume, it is possible to control so as to reduce the maximum value of the amplification factor in the amplitude adjustment unit 213. That is, when the amplitude level detected by the amplitude detector 214 is Y or less, a predetermined amount of value is added to the detected amplitude level if wind is detected. Then, since the amplification factor setting unit 215 detects that the audio signal has a level equal to or higher than the detected amplitude level, the amplification factor in the amplitude adjustment unit 213 is controlled to be close to Gnor. Further, when the air volume is large, the value added to the detected amplitude level is increased compared to when the air volume is small. By doing in this way, it can also be controlled to reduce the maximum value of the amplification factor in the amplitude adjustment unit 213.

  In the present embodiment, the air volume is detected based on the difference signal between the two audio signals. However, the low frequency components of the two audio signals may be simply compared. Alternatively, the air volume may be detected using a unit capable of detecting air displacement such as a wind pressure sensor, an anemometer, or a device using a laser and a camera.

  In the present embodiment, the case of generating 5.1ch sound has been described. However, the present invention is not limited to this configuration, and the present embodiment is applicable to the audio processing of the present embodiment even when generating multi-sound. is there.

  In the present embodiment, the case where the air volume information 1 and the air volume information 2 are input to the air volume comparison unit 402 has been described. However, two or more airflow information may be output, and in that case, the airflow information indicating that the airflow is the largest may be input to the ALC 205.

  In this embodiment, the image pickup apparatus has been described. However, the sound processing to the sound input unit 102 according to this embodiment may be any apparatus that records or inputs external sound and outputs the sound. Even a simple device can be applied. For example, you may apply to an IC recorder, a mobile telephone, etc.

Claims (35)

A plurality of sound collecting means;
Processing means for processing audio signals obtained by the plurality of sound collecting means,
The processing means amplifies the audio signal obtained by the sound collecting means with an amplification factor that is in accordance with the level of the audio signal obtained by the sound collecting means and that is not greater than a predetermined amplification factor. The sound processing apparatus is characterized in that the predetermined amplification factor is decreased as the magnitude of wind noise included in the sound signal obtained by the sound collecting means increases.   The audio processing apparatus according to claim 1, wherein the processing unit generates a multi-channel audio signal based on the audio signals obtained by the plurality of sound collecting units.   The sound processing apparatus according to claim 1, wherein the processing means detects the magnitude of noise caused by wind contained in the sound signals obtained by the plurality of sound collecting means.   The sound processing apparatus according to claim 3, wherein the processing means detects the magnitude of noise caused by wind based on the difference component of the sound signals obtained by the plurality of sound collecting means.   5. The audio processing apparatus according to claim 1, wherein the processing unit reduces noise caused by wind included in the audio signals obtained by the plurality of sound collecting units.   The processing means has an amplification factor according to the level of the sound signal obtained by the sound collecting means after reducing noise caused by wind contained in the sound signals obtained by the plurality of sound collecting means, and The audio processing apparatus according to claim 5, wherein amplification is performed at an amplification factor that is not greater than the predetermined amplification factor. The processing means detects the magnitude of noise caused by wind based on the sound signal obtained by the first sound collecting means and the sound signal obtained by the second sound collecting means, and the third sound collecting means. Detecting the magnitude of noise caused by wind based on the voice signal obtained by the means and the voice signal obtained by the fourth sound collecting means;
The processing means includes a magnitude of wind noise detected based on the sound signal obtained by the first sound collecting means and the sound signal obtained by the second sound collecting means, and third sound collecting means. The predetermined amplification factor is changed based on the larger one of the magnitude of the noise caused by the wind detected based on the voice signal obtained by the above and the voice signal obtained by the fourth sound collecting means. The sound processing apparatus according to claim 1, wherein   8. The audio processing apparatus according to claim 7, wherein a 5-channel or 6-channel audio signal is generated based on the audio signals obtained by the first to fourth sound collecting means. A plurality of sound collecting means;
Processing means for processing audio signals obtained by the plurality of sound collecting means;
The processing means has an amplification factor according to the level of the audio signal obtained by the sound collecting means, and the amplification factor does not become larger than a predetermined amplification factor for the audio signals obtained by the plurality of sound collecting means. The sound processing apparatus, wherein the predetermined amplification factor is changed to be smaller as the difference component between the sound signals obtained by the plurality of sound collecting means is larger.   The audio processing apparatus according to claim 9, wherein the processing unit generates a multi-channel audio signal based on the audio signals obtained by the plurality of sound collecting units.   The sound processing apparatus according to claim 9 or 10, wherein the processing means reduces noise caused by wind included in the sound signals obtained by the plurality of sound collecting means.   12. The processing means according to claim 11, wherein after the noise due to wind included in the audio signals obtained by the plurality of sound collecting means is reduced, the processing means amplifies with an amplification factor that is not greater than the predetermined amplification factor. The speech processing apparatus according to the description.   The processing means includes a difference component between the sound signal obtained by the first sound collecting means and the sound signal obtained by the second sound collecting means, the sound signal obtained by the third sound collecting means, and the first sound signal. The predetermined amplification factor is changed based on the larger value of the difference components from the audio signal obtained by the sound collecting means of No. 4 according to any one of claims 9 to 12. The speech processing apparatus according to the description.   14. The audio processing apparatus according to claim 13, wherein a 5-channel or 6-channel audio signal is generated based on the audio signals obtained by the first to fourth sound collecting means.   The audio processing apparatus according to claim 2, wherein the processing unit amplifies the audio signals of the plurality of channels with an amplification factor that does not become larger than the predetermined amplification factor.   The audio processing apparatus according to claim 2 or 10, wherein the predetermined amplification factor is an amplification factor when an audio level of the audio signals of the plurality of channels is smaller than a predetermined level.   11. The audio processing apparatus according to claim 2, wherein the processing unit compresses the audio signals of the plurality of channels. An acquisition means for acquiring video data;
18. The sound processing apparatus according to claim 1, further comprising recording means for recording on a recording medium together with sound data indicating the sound signal obtained by the processing means. The audio signal obtained by multiple sound collecting means, a gain corresponding to the level of the audio signal obtained by the sound collection unit, and the speech processing of amplifying an amplification factor which is not greater than a predetermined amplification factor A method,
The larger size of the wind noise included in the audio signal obtained by the prior SL sound collector unit, the audio processing method and changes reduce the predetermined amplification factor. An audio processing method for amplifying an audio signal obtained by a plurality of sound collecting means with an amplification factor corresponding to the level of the audio signal obtained by the sound collecting means and not exceeding a predetermined amplification factor Because
The audio processing method, wherein the predetermined amplification factor is changed to be smaller as the difference component of the audio signals obtained by the plurality of sound collecting means is larger.   21. The sound processing method according to claim 19, wherein noise caused by wind included in sound signals obtained by the plurality of sound collecting means is reduced.   The amplification factor according to the level of the audio signal obtained by the sound collecting unit after reducing noise caused by wind included in the audio signal obtained by the plurality of sound collecting units, and the predetermined amplification factor The audio processing method according to claim 21, wherein amplification is performed at an amplification factor that does not become larger.   23. The amplification factor according to any one of claims 19 to 22, wherein the predetermined amplification factor is an amplification factor when an audio level of an audio signal obtained by the plurality of sound collecting means is smaller than a predetermined level. The voice processing method described. A plurality of sound collecting means;
Processing means for processing audio signals obtained by the plurality of sound collecting means,
The processing means amplifies the audio signal obtained by the sound collecting means with an amplification factor that is in accordance with the level of the audio signal obtained by the sound collecting means and that is not greater than a predetermined amplification factor. And the predetermined amplification factor is increased as the magnitude of noise caused by wind contained in the audio signal obtained by the sound collecting means is reduced. 25. The audio processing apparatus according to claim 24, wherein the processing unit generates a multi-channel audio signal based on the audio signals obtained by the plurality of sound collecting units. 26. The sound processing apparatus according to claim 24, wherein the processing means detects the magnitude of noise caused by wind included in the sound signals obtained by the plurality of sound collecting means. 27. The audio processing apparatus according to claim 26, wherein the processing means detects the magnitude of noise caused by wind based on a difference component of the audio signals obtained by the plurality of sound collecting means. The sound processing apparatus according to any one of claims 24 to 27, wherein the processing means reduces noise caused by wind included in the sound signals obtained by the plurality of sound collecting means. The processing means has an amplification factor according to the level of the sound signal obtained by the sound collecting means after reducing noise caused by wind contained in the sound signals obtained by the plurality of sound collecting means, and 29. The audio processing apparatus according to claim 28, wherein amplification is performed at an amplification factor that is not greater than the predetermined amplification factor. An audio processing method for amplifying an audio signal obtained by a plurality of sound collecting means with an amplification factor corresponding to the level of the audio signal obtained by the sound collecting means and not exceeding a predetermined amplification factor Because
The audio processing method according to claim 1, wherein the predetermined amplification factor is increased as the magnitude of noise caused by wind included in the audio signal obtained by the sound collecting means is smaller. A plurality of sound collecting means;
Processing means for processing audio signals obtained by the plurality of sound collecting means;
The processing means has an amplification factor according to the level of the audio signal obtained by the sound collecting means, and the amplification factor does not become larger than a predetermined amplification factor for the audio signals obtained by the plurality of sound collecting means. The sound processing apparatus, wherein the predetermined amplification factor is increased as the difference component of the sound signals obtained by the plurality of sound collecting means is smaller. 32. The audio processing apparatus according to claim 31, wherein the processing unit generates a multi-channel audio signal based on the audio signals obtained by the plurality of sound collecting units. The sound processing apparatus according to claim 31 or 32, wherein the processing means reduces noise caused by wind included in the sound signals obtained by the plurality of sound collecting means. 34. The processing unit according to claim 33, wherein after the noise due to wind included in the audio signals obtained by the plurality of sound collecting units is reduced, the processing unit amplifies the signal with an amplification factor that is not greater than the predetermined amplification factor. The speech processing apparatus according to the description. An audio processing method for amplifying an audio signal obtained by a plurality of sound collecting means with an amplification factor corresponding to the level of the audio signal obtained by the sound collecting means and not exceeding a predetermined amplification factor Because
The audio processing method, wherein the predetermined amplification factor is increased as the difference component of the audio signals obtained by the plurality of sound collecting means is smaller.

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