JP5340127B2 - Audio signal processing apparatus and control method of audio signal processing apparatus - 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 imaging devices include a microphone for collecting external sound and generating a sound signal. However, when wind hits the surface or the like, noise that is annoying to the user may occur. It was. Such noise generated by the influence of wind around the device is generally called wind noise.

  In order to solve such a problem, a technique of attenuating a low frequency component that is greatly affected by wind noise by a high-pass filter that attenuates, for example, a low-frequency component of 1 kHz or less of audio 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 the past, when wind noise was included in frequencies that could not be attenuated, it was difficult to completely reduce wind noise, and wind noise components with unstable volume (level) remained in the audio signal. There was a case. For this reason, in Patent Document 1, if wind noise with unstable volume remains in an audio signal, the ALC repeatedly amplifies and attenuates the audio signal. For example, a sound that should be at a constant volume such as a human voice is unacceptable. There was a problem that the sound became stable. When such an audio signal is reproduced, the volume of the voice such as the voice of the person who originally wants to hear becomes unstable and difficult to hear.

  Therefore, the present invention reduces the instability of the ALC output sound by slowing the change rate of the ALC gain when the level of wind noise (air volume, wind speed, wind pressure) is high. An object is to provide a signal processing device.

  Even when the air volume level is high, the wind speed is high, or the wind pressure is high, there is a high possibility that the level of wind noise included in the audio signal will be high.

Audio processing apparatus of the present invention, in order to achieve the above object, an audio signal processing apparatus including a sound collection unit, according to the wind effects of the device around included in the audio signal obtained by said sound collecting means Detecting means for detecting a level of a noise component; and adjusting means for amplifying the audio signal with an amplification factor corresponding to the level of the audio signal, wherein the adjusting means increases the amplification factor when the level of the audio signal increases. the lowered, and the level of the audio signal that a low increase the amplification factor, the adjustment means, when increasing the gain, the more when the higher level of said noise component detected by said detecting means, said amplifier The rate change rate is slow.

  According to the present invention, the instability of output sound can be reduced by slowing the rate of change of the ALC gain when the wind noise level is high. As a result, when the wind noise level is high, it is possible to obtain an audio signal in which the audio level such as a human voice is less likely to become unstable.

It is a block diagram of the imaging device of a present Example. 3 is a block diagram of a voice input unit 102. FIG. It is a figure which shows the amplification factor corresponding to an amplitude level. It is a figure which shows the detection result of the amplitude level of an audio | voice.

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

  As an audio signal processing device capable of processing an audio signal, an imaging device will be described as an example.

  FIG. 1 is a block diagram illustrating the configuration of the imaging apparatus 100 according to the first embodiment.

  In FIG. 1, an imaging unit 101 converts an optical image of a subject captured by a photographing lens into an image signal by an imaging element, performs analog-digital conversion, image adjustment processing, and the like, and generates image data. The audio input unit 102 collects audio around the imaging device 100 by a plurality of microphones built in or connected via audio terminals, and performs analog-digital conversion, audio processing, and the like to generate audio data. The microphone converts voice vibration into a voice signal. The memory 103 temporarily stores the image data obtained by the imaging unit 101 and the audio data obtained by the audio input unit 102. The display control unit 104 displays a video related to the image data obtained by the imaging unit 101, an operation screen of the imaging device 100, a menu screen, and the like on the display unit 105 or an external display via a video terminal (not shown). . The encoding processing unit 106 reads out image data and audio data temporarily stored in the memory 103, performs predetermined encoding, and generates compressed image data, compressed audio data, and the like. The recording / reproducing unit 107 records the compressed image data, the compressed audio data, and the like generated by the encoding processing unit 106 on the recording medium 108, or the compressed image data, the compressed audio data recorded on the recording medium 108, Read various data and programs. Here, the recording medium 108 includes all types of recording media such as a magnetic disk, an optical disk, and a semiconductor memory as long as compressed image data, compressed audio data, and the like can be recorded.

  The control unit 109 can control each block of the imaging apparatus 100 by transmitting a control signal to each block of the imaging apparatus 100, and includes a CPU, a memory, and the like for performing various controls. The operation unit 110 includes buttons, a dial, and the like, and transmits an instruction signal to the control unit 109 according to a user operation. The audio output unit 111 outputs the compressed audio data reproduced by the recording / reproducing unit 107 and the audio data output by the control unit 109 to the speaker 112, the audio terminal, and the like. The external output unit 113 outputs the compressed video data and the compressed audio data reproduced by the recording / reproducing unit 107 to an external device. The data bus 114 supplies various data such as audio data and image data and various control signals to each block of the imaging apparatus 100.

  Here, the normal operation of the imaging apparatus 100 of the present embodiment will be described.

  The imaging apparatus 100 according to the present embodiment supplies power to each block of the imaging apparatus from a power supply unit (not illustrated) in response to an instruction to turn on the power by operating the operation unit 110 by the user. .

  When the power is supplied, the control unit 109 checks, for example, which mode the mode selector switch of the operation unit 110 is in, for example, a shooting mode, a reproduction mode, or the like by an instruction signal from the operation unit 110. In the moving image recording mode, the image data obtained by the imaging unit 101 and the audio data obtained by the audio input unit 102 are stored as one file. In the reproduction mode, the compressed image data recorded on the recording medium 108 is reproduced by the recording / reproducing unit 107 and displayed on the display unit 105.

  In the moving image recording mode, first, the control unit 109 transmits a control signal to each block of the imaging apparatus 100 so as to shift to the shooting standby state, and performs the following operation.

  The imaging unit 101 converts an optical image of a subject captured by a photographing lens into an image signal by an imaging element, performs analog-digital conversion, image adjustment processing, and the like, and generates image data. Then, the obtained image data is transmitted to the display processing unit 104 and displayed on the display unit 105. The user prepares for shooting while viewing the screen displayed in this way.

  The audio input unit 102 digitally converts analog audio signals obtained by a plurality of microphones and processes the obtained digital audio signals to generate multi-channel audio data. Then, the obtained audio data is transmitted to the audio output unit 111 and is output as audio from the connected speaker 112 or an unillustrated earphone. The user can also adjust the manual volume to determine the recording volume while listening to the sound output in this way.

  Next, when a shooting start instruction signal is transmitted to the control unit 109 by the user operating the recording button of the operation unit 110, the control unit 109 transmits a shooting start instruction signal to each block of the imaging apparatus 100. Then, the following operation is performed.

  The imaging unit 101 converts an optical image of a subject captured by a photographing lens into an image signal by an imaging element, performs analog-digital conversion, image adjustment processing, and the like, and generates image data. Then, the obtained image data is transmitted to the display processing unit 104 and displayed on the display unit 105. Further, the obtained image data is transmitted to the memory 103.

  The audio input unit 102 digitally converts analog audio signals obtained by a plurality of microphones and processes the obtained digital audio signals to generate multi-channel audio data. Then, the obtained audio data is transmitted to the memory 103.

  The encoding processing unit 106 reads out image data and audio data temporarily stored in the memory 103, performs predetermined encoding, and generates compressed image data, compressed audio data, and the like.

  Then, the control unit 109 synthesizes these compressed image data and compressed audio data, forms a data stream, and outputs the data stream to the recording / reproducing unit 107.

  The recording / playback unit 107 writes the data stream to the recording medium 108 as one moving image file under the management of a file system such as UDF or FAT.

  The above operation is continued during shooting.

  When the user operates the recording button of the operation unit 110 and a shooting end instruction signal is transmitted to the control unit 109, the control unit 109 transmits a shooting end instruction signal to each block of the imaging apparatus 100. The following operations are performed.

  The imaging unit 101 and the audio input unit 102 stop generating image data and audio data, respectively.

  The encoding processing unit 106 reads the remaining image data and audio data stored in the memory, performs predetermined encoding, and stops the operation when generation of compressed image data, compressed audio data, and the like is completed.

  Then, the control unit 109 synthesizes these last compressed image data and compressed audio data, forms a data stream, and outputs the data stream to the recording / reproducing unit 107.

  The recording / playback unit 107 writes the data stream to the recording medium 108 as one moving image file under the management of a file system such as UDF or FAT. When the supply of the data stream is stopped, the moving image file is completed and the recording operation is stopped.

  When the recording operation stops, the control unit 109 transmits a control signal to each block of the imaging apparatus 100 so as to shift to the shooting standby state, and returns to the shooting standby state.

  Next, in the playback mode, the control unit 109 transmits a control signal to each block of the imaging apparatus 100 so as to shift to the playback state, and performs the following operation.

  The recording / playback unit 107 reads a moving image file composed of compressed image data and compressed audio data recorded on the recording medium 108, and sends the read compressed image data and compressed audio data to the encoding processing unit 106. The encoding processing unit 106 decodes the compressed image data and the compressed audio data and transmits them to the display control unit 104 and the audio output unit 111, respectively. The display control unit 104 causes the display unit 105 to display the decoded image data. The audio output unit 111 outputs the decoded audio data from an external speaker built in or attached.

  As described above, the image pickup apparatus of the present embodiment records and reproduces images and sounds.

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

  In FIG. 2, a microphone unit 201 collects sound and converts sound vibration into an electric signal to obtain a sound signal. As described above, even if the microphone unit 201 is built in the image capturing apparatus, the sound input terminal of the image capturing apparatus An external microphone unit connected to may be used. In this embodiment, an example in which the microphone unit 201 includes two microphone elements will be described, but any number of microphone elements may be used. The AD converter 202 converts the audio signal obtained by the microphone unit 201 from an analog signal to a digital signal. The stereo conversion unit 203 converts the audio signal obtained by the microphone unit 201 into stereo audio data. Since a method for generating a stereo audio signal from two audio signals uses an existing technique, the description thereof is omitted in this embodiment. The wind noise reduction unit 204 reduces noise (wind noise) of low frequency components (for example, a frequency of about 2 kHz or less) generated due to the influence of wind around the apparatus. The auto level controllers (hereinafter, ALC) 205L and 205R have a function of keeping the level of the input audio signal at an appropriate level. In the ALC 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 uses the fact that the two audio signals obtained by the microphone unit have a low correlation in the low frequency component (for example, 1 kHz or less) with respect to noise generated by the influence of wind. Wind noise is removed. 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). In general, it is known that wind noise is output from a plurality of microphones as an uncorrelated voice signal. Therefore, the value of the difference signal is small when the wind noise level around the apparatus is small, and the value of the difference signal is large when the wind noise level around the apparatus is large. In the present embodiment, whether the level of wind noise (noise component) is large or small is detected 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, the level of the wind noise is large (the volume of air is large, the wind speed is fast, the wind pressure is large), and if the value of the difference signal is small, the level of the wind noise is Is output as air volume information indicating that the air volume is small (the air volume is low, the wind speed is slow, and the wind pressure is low).

  In this embodiment, if the value of the difference signal is extremely small in a situation where the wind is not blowing, the air volume information indicating the wind noise level may not be output. In the present embodiment, an example of outputting a two-stage signal indicating whether the level of wind noise is large or small will be described.

  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. If the value of the air volume information detected by the air volume detector 207 indicates that the level of wind noise is high, the HPF 208 sets the cutoff frequency of the low-frequency component to be attenuated to 2 kHz, for example. Further, if the value of the air volume information indicates that the level of wind noise is small, the cutoff frequency is set to 500 Hz. Or, if the value of the airflow information indicates that the level of wind noise is high, increase the attenuation of the low frequency component, and if the value of the airflow information indicates that the level of wind noise is low, the low frequency component The amount of attenuation may be reduced. 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 noise (wind noise) caused by wind around the apparatus.

  Here, the ALC 205L / 205R will be further described.

  In the ALC 205L / 205R of this 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. A similar circuit is provided for the Rch.

  First, the operation when the wind noise level is almost zero will be described.

  The Lch audio signal input to the ALC 205 is delayed by several ms by the delay unit 212, and the amplitude of the audio signal is amplified or attenuated by the amplitude control unit 213. As for the amplification factor in the amplitude control unit 213, the amplitude detection unit 214 detects the amplitude of the audio signal input to the ALC 205, and transmits a detection result corresponding to the detected value to the amplification factor setting unit 215. Set by.

  The amplitude detection unit 214 (audio level detection unit) of this embodiment detects the audio level for each sample of the audio signal (digital signal). If the level of m samples is higher than the level of m−1 samples as the detection result, the operation of outputting the level of m samples as the detection result is repeated. On the other hand, if the level of n samples is lower than the level of m−1 samples, the value obtained by subtracting a predetermined value A from the level of m−1 samples is set to the level of n samples and is output as a detection result. Is repeated. In other words, the amplitude detection unit 214 of the present embodiment outputs a level that follows the audio level of the audio signal as a detection result until the peak of the audio signal is changed. Then, after the peak of the audio signal, a value obtained by continuing to subtract the predetermined value A until the previous detection result becomes larger than the level of the audio signal is output as the detection result. (Where n is an integer of 1 or more).

  The amplification factor setting unit 215 sets the amplification factor of the audio signal in the amplitude adjustment unit 213 according to the detection result output from the amplitude detection unit 214. The relationship between the detection result of the amplitude detection unit 214 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 FIG. 3, the horizontal axis represents the detection result of the amplitude detection unit 214 that is input, and the vertical axis represents the amplification factor. As can be seen from FIG. 3, when the level of the detection result of the amplitude detection unit 214 is Y or more and X or less, the amplification factor Gnor is set in the amplitude adjustment unit 213 to amplify the audio signal. Further, when the detection result level becomes X or more, the amplification factor is gradually decreased from Gnor according to the detection result level, and when the detection result level becomes a predetermined high value or more, the amplification factor is set to Glim. Set to. Further, when the detection result level becomes Y or less, the amplification factor is gradually increased from Gnor according to the detection result level, and when the detection result level becomes a predetermined low value or less, the amplification factor is set to Grec. . Here, Grec> Gnor> Glim. That is, as described above, when the detection result level output from the amplitude detection unit 214 is low, the amplification factor of the audio signal is increased, and when the detection result level is high, the amplification factor is decreased. . In the present embodiment, the example in which the relationship between the detection result of the amplitude detection unit 214 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. However, for example, a relationship that linearly responds to the level of the detection result may be used. For example, the relationship may be such that the amplification factor gradually increases as the detection result level decreases from the detection result level at which Glim is set to the detection result level at which Grec is set. In this embodiment, when the level of the detection result becomes Y or less, the amplification factor is gradually increased from Gnor to Grec. However, it may not be increased.

  The ALC 205 is designed to prevent the sound level from becoming excessively high and the sound reproducibility from being lost. Therefore, when the audio signal continues to increase, the amplitude detection unit 214 is configured as described above so that the amplification factor according to the level of the input audio signal is immediately reflected. That is, the level following the audio signal is output as a detection result until the peak of the audio signal is changed. By doing so, the amplification factor setting unit 215 sets the amplification factor according to the level of the input audio signal until the peak of the audio signal is reached.

  In addition, the ALC 205 gradually increases the amplification factor when the sound level decreases. This is because if the amplification factor changes following the sound level, the sound level becomes constant, but the inflection is lost, making it difficult to hear. Therefore, after the peak of the audio signal, the amplitude detection unit 214 outputs a value obtained by continuously pulling the predetermined value A until the previous detection result becomes larger than the level of the audio signal. By doing so, the amplification factor setting unit 215 sets the amplification factor according to the level of the detection result of the amplitude detection unit 214 after the peak of the audio signal. That is, since the detection result is a value obtained by continuously pulling the predetermined value A, if the detection result is X or more, the amplification factor gradually increases to Gnor, and when the detection result becomes Y or less. , The amplification factor gradually increases from Gnor.

  With such a configuration, for example, it takes about 0.4 seconds to return from the state where Glim is set by the amplification factor setting unit 215 to Gnor.

  Next, the operation of the ALC 205 when wind noise occurs in the imaging apparatus of the present embodiment will be described.

  In the image pickup apparatus of the present embodiment, the rate of change of the amplification factor after the peak of the audio signal is made gentler when the wind noise level is large than when the wind noise is small. For example, when the wind noise level is high, it takes about 2.0 seconds to return from the state where Glim is set by the amplification factor setting unit 215 to Gnor. When the wind noise level is low, for example, it takes about 1.2 seconds to return from the state where Glim is set by the amplification factor setting unit 215 to Gnor.

  In this way, when the wind noise level is high, it is possible to prevent the amplification factor from becoming unstable due to the wind noise.

  A specific operation will be described below.

  The delay unit 212 and the amplitude adjustment unit 213 operate in the same manner as when the wind noise level is almost zero. The amplitude detection unit 214 operates in the same manner as when the wind noise level is almost zero, but operates partially differently. The same is true in that the level following the audio signal is output as a detection result until the peak of the audio signal is changed. However, when the wind noise level is low, after the peak of the audio signal, a value obtained by continuing to pull the predetermined value B until the previous detection result becomes larger than the level of the audio signal is output as the detection result. When the wind noise level is high, after the peak of the audio signal, a value obtained by continuing to subtract the predetermined value C until the previous detection result becomes larger than the level of the audio signal is output as the detection result. However, A> B> C.

  By doing so, when the wind noise level is high after the peak of the audio signal, the time for the detection result level to be lowered is delayed compared to when the wind noise level is low. This is shown in FIG. In FIG. 4, the horizontal axis represents time, and the vertical axis represents the audio level (detection result level). In FIG. 4, the broken line indicates the absolute value of the input audio signal. FIG. 4A shows the value of the detection result output from the amplitude detection unit 214 when the wind noise level is low (when B is subtracted), and 401 is the detection level of the detection result. FIG. 4B shows the detection result value output from the amplitude detection unit 214 when the wind noise level is high (when C is subtracted), and 402 is the detection level of the detection result.

  As can be seen from 401 and 402, when the wind noise level is high, the time during which the detection result value decreases is longer than when the wind noise level is low. Then, the amplification factor setting unit 215 sets the amplification factor according to the correspondence shown in FIG. 3 in the amplitude adjustment unit 213 according to the detection result.

  According to the control as described above, in the imaging apparatus of the present embodiment, when the wind noise level is high, the rate at which the amplification factor changes is slower (the fluctuation is gradual) than when the wind noise level is low. . Therefore, when the wind noise level is high, it is possible to prevent the amplification factor from fluctuating unstable due to the increase or decrease in the wind noise level, and to set a stable amplification factor. That is, when the level of wind noise is high, it is possible to obtain a voice signal in which the level of voice such as a human voice is less likely to become unstable.

  In the present embodiment, the amplitude detection unit 214 adjusts the value subtracted from the level of the audio signal, so that when the wind noise level is high, the rate at which the amplification factor changes is slower than when the wind noise level is low. (Slow fluctuations). However, the level of the audio signal may be multiplied by a predetermined value smaller than 1, and the value to be multiplied may be adjusted. In this case, the amplitude detection unit 214 outputs a level following the audio signal as a detection result until the peak of the audio signal is obtained. When the wind noise level is low, after the peak of the audio signal, the detection result is a value obtained by continuously multiplying the predetermined value D (D <1) until the previous detection result becomes larger than the audio signal level. Output sequentially. Also, when the wind noise level is high, after the peak of the audio signal, a value continuously multiplied by a predetermined value E (D <E <1) is detected until the previous detection result becomes larger than the audio signal level. Output as a result.

  Further, the amplitude detection unit 214 may output the level of the audio signal as it is to the amplification factor setting unit 215 as a detection result. In this case, when the amplification factor is increased, the amplification factor setting unit 215 sets the rate of change of the amplification factor to be slower when the wind noise level is high than when the wind noise level is low.

  In this embodiment, the wind noise level is detected based on the difference signal between the two audio signals, but the low frequency components of the two audio signals may be simply compared. Further, information related to wind 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. This utilizes the fact that the wind noise level is high when the wind pressure is high, the wind speed is fast, and the air volume is large.

  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 this embodiment, the case where the sound is 2ch has been described. However, the same can be applied to the case where 5.1ch sound is generated with two or more microphones. If the method is other than detecting the difference signal between the two audio signals, the variation of the amplification factor is moderated according to the air volume (wind speed, wind pressure).

Claims (16)

An audio signal processing apparatus including a sound collecting unit,
Detecting means for detecting the level of the noise component due to the wind effects of the device around included in the audio signal obtained by said sound collecting means,
Adjusting means for amplifying the audio signal at an amplification factor according to the level of the audio signal;
It said adjusting means lowers the amplification factor level is high in the audio signal, increasing the amplification factor and the level of the audio signal that a low,
The adjustment means, when increasing the amplification factor, slows the rate of change of the amplification factor as the level of the noise component detected by the detection means is higher. It said adjusting means, chromatic and audio level detecting means for outputting a detection result detected a level of the audio signal, and a determination means for determining the amplification factor according to the detection result output by the audio level detector And
The audio level detecting means, wherein when the level of the audio signal may turn low, as at higher levels of the noise component detected by said detection means, to ensure that the rate of change in the detection result is slow the audio signal processing apparatus according to claim 1, wherein the. The detecting device, the audio signal processing apparatus according to claim 1 or 2, wherein the detecting the level of the noise component based on the audio signal obtained by a plurality of said sound collecting means. Said adjusting means determines a voice level detecting means for outputting a detection result by detecting the level of the audio signal at least one sample per, the amplification factor in accordance with a detection result output by the audio level detector Determining means,
The audio level detecting unit, when the audio signal level may turn low, n-1-th sample of the output to continue (n as a result of detection of a value obtained by subtracting from the detection result of the predetermined value n samples An integer greater than or equal to 1),
The audio level detecting means, the smaller the higher the level of said noise component detected by the detecting means, the audio signal according to any one of claims 1 to 3, characterized in that to reduce the predetermined value Processing equipment. 5. The audio signal processing apparatus according to claim 4 , wherein the audio level detection unit increases the predetermined value as the level of the noise component detected by the detection unit is lower. Said adjusting means determines a voice level detecting means for outputting a detection result by detecting the level of the audio signal at least one sample per, the amplification factor in accordance with a detection result output by the audio level detector Determining means,
When the level of the audio signal decreases, the audio level detection means continues to output a value obtained by multiplying the detection result of the (n-1) th sample by a predetermined value smaller than 1 as the detection result of n samples (however, n Is an integer of 1 or more),
The audio level detecting means, the smaller the higher the level of said noise component detected by the detecting means, the audio signal according to any one of claims 1 to 3, characterized in that to increase the predetermined value Processing equipment. The audio signal processing apparatus according to claim 6 , wherein the audio level detection unit decreases the predetermined value as the level of the noise component detected by the detection unit is lower. The audio signal processing apparatus according to claim 1, wherein the audio signal processing apparatus is a mobile phone. A method for controlling an audio signal processing device including sound collection means,
A detection step of detecting a level of a noise component due to an influence of wind around the device included in the sound signal obtained by the sound collecting means;
An adjustment step of amplifying the audio signal at an amplification factor according to the level of the audio signal,
In the adjustment step, when the level of the audio signal becomes high, the amplification factor is lowered, and when the level of the audio signal becomes low, the amplification factor is raised,
In the adjustment step, when the amplification factor is increased, the rate of change of the amplification factor is decreased as the level of the noise component detected by the detection unit is higher. Method. The adjustment step includes
An audio level detection step of detecting the level of the audio signal and outputting a detection result;
Determining the amplification factor according to the detection result of the audio level detection step,
In the sound level detection step, when the level of the sound signal becomes low, the change rate of the detection result becomes slower as the level of the noise component detected by the detection means becomes higher. The method for controlling an audio signal processing device according to claim 9, wherein the method is a control method. 11. The method of controlling an audio signal processing apparatus according to claim 9, wherein in the detecting step, the level of the noise component is detected based on audio signals obtained by a plurality of the sound collecting means. The adjustment step includes
An audio level detection step of detecting the level of the audio signal at least for each sample and outputting a detection result;
Determining the amplification factor according to the detection result of the audio level detection step,
In the audio level detection step, when the level of the audio signal becomes low, a value obtained by subtracting a predetermined value from the detection result of the (n-1) th sample is continuously output as the detection result of n samples (where n is 1). An integer greater than or equal to)
The audio signal according to any one of claims 9 to 11, wherein the audio level detection step decreases the predetermined value as the level of the noise component detected in the detection step is higher. A method for controlling a processing apparatus. 13. The method of controlling an audio signal processing device according to claim 12, wherein in the audio level detection step, the predetermined value is increased as the level of the noise component detected in the detection step is lower. The adjustment step includes
An audio level detection step of detecting the level of the audio signal at least for each sample and outputting a detection result;
Determining the amplification factor according to the detection result output by the audio level detection step,
In the audio level detection step, when the level of the audio signal decreases, a value obtained by multiplying the detection result of the (n−1) th sample by a predetermined value smaller than 1 is continuously output as the detection result of n samples (however, n Is an integer of 1 or more),
12. The audio signal according to claim 9, wherein the audio level detection step increases the predetermined value as the level of the noise component detected in the detection step is higher. A method for controlling a processing apparatus. 15. The method of controlling an audio signal processing device according to claim 14, wherein the audio level detection step decreases the predetermined value as the level of the noise component detected by the detection means is lower. 16. The method of controlling an audio signal processing device according to claim 9, wherein the audio signal processing device is a mobile phone.

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