JP4228924B2 - Wind noise reduction device - Google Patents

Description

  The present invention relates to a wind noise reduction device, and more particularly to a wind noise reduction device that reduces wind noise in a surround microphone.

In the prior art, a surround sound microphone equipped with a wind noise reduction circuit, that is, a wind noise reduction device using three microphones will be described with reference to FIG. It is compatible with 3 channels that can be processed.
The Rch (right channel) audio signal collected by the second microphone 111, the Cch (center channel) audio signal collected by the first microphone 110, and the third microphone 112 collected. Each of the audio signals of the Lch (left channel) is supplied to the corresponding ADCs 116, 117, 118 through the corresponding amplifiers 113, 114, 115.

Each of the ADCs 116, 117, and 118 converts an analog audio signal from each of the corresponding amplifiers 113, 114, and 115 into a digital signal.
The Rch digital audio signal R from the ADC 116 is supplied to the delay unit 120, the LPF 121, and the negative terminal of the arithmetic unit 119, and the Cch digital audio signal C from the ADC 117 is supplied to the delay unit 122 and the LPF 123. The Lch digital audio signal L supplied from the ADC 118 is supplied to the delay unit 124, the LPF 125, and the + side terminal of the computing unit 119.

The computing unit 119 subtracts the Rch digital audio signal R supplied to the − side terminal from the Lch digital audio signal L supplied to the + side terminal, and outputs the (LR) signal as the output signal to the LPF 221. And a wind sound level detection signal is generated through the amplifier 222, DET 223, and coefficient generation unit 224.
The wind sound level detection signal has a high level when the wind sound is high, and becomes zero when there is no wind sound.

  Further, in the LPF 121, the Rch digital audio signal (Rch wind sound signal) Rw limited to the wind sound band is supplied to the plus side terminal of the computing unit 130, one plus side terminal of the computing unit 126, and the computing unit 27. The Cch digital audio signal (Cch wind sound signal) Cw, which is supplied to one of the positive side terminals and limited to the wind noise band in the LPF 123, is added to the positive side terminal of the computing unit 131 and the other + side of the computing unit 126. The Lch digital audio signal (Lch wind sound signal) Lw supplied to the side terminal and one plus side terminal of the computing unit 128 and restricted to the wind noise band in the LPF 125 is the plus side terminal of the computing unit 129. The signal is input to the other + side terminal of the computing unit 128 and the other + side terminal of the computing unit 127.

  Further, an (Rw + Cw) signal that is an addition signal of the Rch wind sound signal Rw and the Cch wind sound signal Cw from the computing unit 126 is supplied to the − side terminal of the computing unit 129, and the + side terminal of the computing unit 129. Is subtracted from the wind sound signal Lw of the Lch supplied to, and supplied to the level variable amplifier 134 as an (Lw−Rw−Cw) signal.

  Similarly, an (Rw + Lw) signal that is an addition signal of the Rch wind sound signal Rw and the Lch wind sound signal Lw from the computing unit 127 is input to the − side terminal of the computing unit 131, and the + side of the computing unit 131. It is subtracted from the Cch wind sound signal Cw supplied to the terminal and supplied to the level variable amplifier 133 as a (Cw−Rw−Lw) signal.

  The (Lw + Cw) signal, which is an addition signal of the Lch wind sound signal Lw and the Cch wind sound signal Cw, from the computing unit 128 is input to the minus terminal of the computing unit 130 and the plus side terminal of the computing unit 130. Is subtracted from the wind sound signal Rw of Rch supplied to, and supplied to the level variable amplifier 132 as a (Rw−Lw−Cw) signal.

  Each of the level variable amplifiers 132, 133, and 134 is level-controlled by the wind sound level detection signal from the coefficient generation unit 224, and the output is large when the wind sound is loud, that is, the level of the wind sound level detection signal is large. On the contrary, when there is no wind noise, the wind noise level detection signal level is controlled to be zero and the output is controlled to zero.

  Further, the output signals from the level variable amplifiers 132, 133, and 134 are input to the negative side terminals of the arithmetic units 135, 136, and 137, respectively, and supplied to the positive side terminals from the corresponding delay units 120, 122, and 124, respectively. Are subtracted from each of the digital audio signals R, C, and L and output as Rch signals, Cch signals, and Lch signals from terminals 140, 141, and 142 corresponding to the output signals, and a wind sound level detection signal is output from a terminal 143. Is output from detection.

The operation of the circuit having such a configuration will be described next.
Here, the Lch sound signal is Ls, the wind sound signal is Lw, the Rch sound signal is Rs, the wind sound signal is Rw, the Cch sound signal is Cs, the wind sound signal is Cw, and the wind sound is maximum. At this time, the output / input ratio of the level variable amplifiers 132, 133, 134 is set to 0.5 times, and the output signals of the Rch signal, Cch signal, and Lch signal output from the output terminals 140, 141, 142 are set. If represented by Ra, Ca, and La, they can be represented by the following formulas (1), (2), and (3).
Ra = (Rs + Rw) −0.5 (Rw−Lw−Cw)
= Rs + 0.5 (Rw + Lw + Cw) (1) Formula Ca = (Cs + Cw) −0.5 (Cw−Rw−Lw)
= Cs + 0.5 (Rw + Lw + Cw) (2) Formula La = (Ls + Lw) −0.5 (Lw−Rw−Cw)
= Ls + 0.5 (Rw + Lw + Cw) (3) equation

In other words, when the wind noise is loud, each wind sound signal at each output becomes a (Rw + Lw + Cw) component and becomes a monaural signal obtained by adding the wind sound signals of all channels. Wind noise signals having no correlation can be greatly reduced by adding them together.
When there is no wind noise, Rw, Cw, and Lw become zero, and the respective audio signals Rs, Cs, and Ls are output.

The delay units 120, 122, and 124 compensate for the delays caused by the LPFs 121, 123, and 125, respectively, on the main line side. Raised.
The LPFs 121, 123, and 125 can extract most of the wind sound signals with the wind sound band as a pass band, and the LPF 221 extracts only the wind sound signals that hardly pass the extremely low frequency and contain almost no sound signal.

Thus, by providing an automatic wind noise reduction circuit for each audio channel, it is possible to reduce the wind noise signal for the audio of each audio channel, regardless of the number of audio channels. It is.
Japanese Patent Application No. 2002-238831 (pages 13-16)

  However, the wind noise reduction circuit described in the prior art is premised on a plurality of microphones having the same characteristics. For example, when the configuration includes a plurality of unidirectional microphones, wind noise is effectively reduced. For example, a combination of a unidirectional microphone and a bidirectional microphone has a problem that the effect cannot be exhibited.

  Therefore, there is a problem that must be solved for a wind noise reduction device that can reduce wind noise even for microphones having different characteristics, for example, a surround microphone that combines a unidirectional microphone and a bidirectional microphone.

  In order to solve the above problems, the wind noise reduction device of the present invention is configured as follows.

(1) The wind noise reduction device is a surround microphone including two first and second unidirectional microphones and one bidirectional microphone, and is obtained by the bidirectional microphone. A first subtracting means for subtracting a band frequency signal including a wind noise signal obtained by the second unidirectional microphone from a band frequency signal including a wind noise signal; Second subtracting means for subtracting a band frequency signal including the wind noise signal obtained by the second unidirectional microphone from a band frequency signal including the wind noise signal obtained by the directional microphone; A first rectifier that rectifies the subtracted signal obtained by the first subtractor by a predetermined amount attenuation; a second rectifier that rectifies the subtracted signal obtained by the second subtractor; The voltage obtained by the first rectifying means and the voltage obtained by the second rectifying means. Determining means for comparing the voltages and outputting the presence or absence of wind noise; and adding means for adding a signal of a band frequency including the wind noise signal obtained by the first and second unidirectional microphones; When the determination means determines that there is no wind noise, the signal of the addition component obtained by the addition means is switched to pass as it is, or when the determination means determines that there is wind noise, it is obtained by the addition means. Switching means for switching the added component signal to pass the signal further passed through the notch filter, and the added component signal obtained by the adding means switched by the switch means, or obtained by the adding means. A signal obtained by further passing a notch filter to the signal of the added component and including the audio signals from the first and second unidirectional microphones and the bidirectional microphone And mixing means for mixing the surround signal composed of a frequency of a signal, comprising comprises a.
(2) The wind noise reduction device according to (1), further comprising an attenuation unit that attenuates a signal switched by the switch unit and supplies the signal to the mixing unit.

(3) The wind noise reduction device is a surround microphone composed of two first and second unidirectional microphones and one bidirectional microphone, and is obtained by the bidirectional microphone. First subtracting means for subtracting a signal of a band frequency including a wind noise signal obtained by the second unidirectional microphone from a signal of a band frequency including a wind noise signal, the first unidirectional signal A second subtracting means for subtracting a band frequency signal including the wind noise signal obtained by the second unidirectional microphone from a band frequency signal including the wind noise signal obtained by the directional microphone; A first rectifier that rectifies the subtracted signal obtained by the first subtractor by a predetermined amount; a second rectifier that rectifies the subtracted signal obtained by the second subtractor; The voltage obtained by the first rectifying means and the voltage obtained by the second rectifying means Determining means for comparing the pressure and outputting the presence or absence of wind noise; and adding means for adding a signal of a band frequency including the wind noise signal obtained by the first and second unidirectional microphones; When the determination means determines that there is no wind noise, the signal of the addition component obtained by the addition means is switched to pass as it is, or when the determination means determines that there is wind noise, it is obtained by the addition means. Switching means for switching the added component signal to pass the signal that has passed through the high-pass filter, and the added component signal obtained by the adding means switched by the switch means, or obtained by the adding means. A signal obtained by further passing a high-pass filter to the signal of the added component, including audio signals from the first and second unidirectional microphones and the bidirectional microphone And mixing means for mixing the surround signal composed of a signal band frequency, comprise a.
(4) The wind noise reduction device according to (3), further comprising an attenuation unit that attenuates the signal switched by the switch unit to a predetermined attenuation level.

(5) The wind noise reduction device is a surround microphone including two first and second unidirectional microphones and one bidirectional microphone, and is obtained by the bidirectional microphone. First subtracting means for subtracting a signal of a band frequency including a wind noise signal obtained by the second unidirectional microphone from a signal of a band frequency including a wind noise signal, the first unidirectional signal A second subtracting means for subtracting a band frequency signal including the wind noise signal obtained by the second unidirectional microphone from a band frequency signal including the wind noise signal obtained by the directional microphone; A first rectifying means for attenuating the subtraction signal obtained by the first subtracting means through each of two types of attenuators having different attenuation amounts and rectifying each; and a subtracting signal obtained by the second subtracting means A second rectifying means for rectifying A determination means for comparing the voltage obtained by the rectifying means and the voltage obtained by the second rectifying means to output the strength of the wind and the presence / absence of the wind, and the first and second unidirectionalities. An adding means for adding a signal of a band frequency including a wind noise signal obtained by a microphone and a signal of an addition component obtained by the adding means are passed as they are when the determining means determines that there is no wind noise. Or when the determination means determines that there is weak wind noise, the addition component signal obtained by the addition means is switched to pass a signal that has passed through a notch filter, or strong by the determination means. Switch means for switching the addition component signal obtained by the addition means to pass a signal that has passed through a high-pass filter when it is determined that there is wind noise; and the switch The signal of the addition component obtained by the addition means, the signal of the addition component obtained by the addition means further passed through the notch filter, or the addition obtained by the addition means The signal obtained by further passing the component signal through the high-pass filter is mixed with the surround signal composed of the signal of the band frequency including the audio signal from the first and second unidirectional microphones and the bidirectional microphone. Mixing means.
(6) The wind noise reduction device according to (5), further comprising an attenuation unit that attenuates the signal switched by the switch unit to a predetermined attenuation level.

(7) The wind noise reduction device is a surround microphone composed of two first and second unidirectional microphones and one bidirectional microphone, and is obtained by the bidirectional microphone. First subtracting means for subtracting a signal of a band frequency including a wind noise signal obtained by the second unidirectional microphone from a signal of a band frequency including a wind noise signal, the first unidirectional signal A second subtracting means for subtracting a band frequency signal including the wind noise signal obtained by the second unidirectional microphone from a band frequency signal including the wind noise signal obtained by the directional microphone; A first rectifying means for attenuating the subtraction signal obtained by the first subtracting means through each of two types of attenuators having different attenuation amounts and rectifying each; and a subtracting signal obtained by the second subtracting means A second rectifying means for rectifying A determination means for comparing the voltage obtained by the rectifying means and the voltage obtained by the second rectifying means to output the strength of the wind and the presence / absence of the wind, and the first and second unidirectionalities. An adding means for adding a signal of a band frequency including a wind noise signal obtained by a microphone and a signal of an addition component obtained by the adding means are passed as they are when the determining means determines that there is no wind noise. Or when the determination means determines that there is weak wind noise, the addition component signal obtained by the addition means is switched to pass a signal that has passed through a notch filter, or strong by the determination means. When it is determined that there is wind noise, the switch that switches the addition component signal obtained by the addition means to pass the signal that has passed through the notch filter and high-pass filter. And an addition component signal obtained by the addition means, a signal obtained by further passing a notch filter to the addition component signal obtained by the addition means, or the addition means switched by the switch means. A signal obtained by passing the obtained addition component signal through a notch filter and a high-pass filter is composed of a signal having a band frequency including audio signals from the first and second unidirectional microphones and the bidirectional microphone. And a mixing means for mixing the generated surround signal.
(8) The wind noise reduction device according to (7), further comprising an attenuation unit that attenuates the signal switched by the switch unit to a predetermined attenuation level.

  As described above, according to the present invention, a voltage is generated by rectifying a signal obtained by subtracting a signal of a band frequency including a wind noise signal between two unidirectional microphones, and A signal that rectifies the signal obtained by subtracting the band frequency signal including the wind noise signal and the band frequency signal including the wind noise signal of any unidirectional microphone to generate a voltage, and determines the presence or absence of wind Of these, when it is determined that there is no wind, the signal added between the two unidirectional microphones is directly passed through and mixed with the surround signal. The signal added between the directional microphones is further passed through the notch filter to reduce the signal by narrowing it down to a narrow-band frequency signal of the wind-specific center frequency, and the signal is mixed with the surround signal. Was it, it is possible to play a wind noise reduction of in accordance with the wind noise.

  Next, embodiments of a wind noise reduction method and a wind noise reduction apparatus according to the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the wind noise reduction device according to the present invention has a configuration of two unidirectional microphones and one bidirectional microphone as a Sarand microphone.
A first amplifier 12 that receives an acoustic signal including wind noise from the first unidirectional microphone 11 and amplifies the signal so that the next-stage signal processing can be performed, and the sound amplified by the first amplifier 12 Among the signals, a first LPF 13 that passes a frequency band mainly including wind noise signals (200 Hz in the embodiment) and a frequency band mainly including human voice among the acoustic signals amplified by the first amplifier 12 are used. A first HPF 14 to pass;
A second amplifier 16 that receives an acoustic signal including wind noise from the bidirectional microphone 15 and amplifies the signal so that the next-stage signal processing can be performed, and wind of the acoustic signal amplified by the second amplifier 16. A second LPF 17 that passes a frequency band mainly including a noise signal (200 Hz in the embodiment), and a second LPF 17 that passes a frequency band mainly including human speech among the acoustic signals amplified by the second amplifier 16. HPF18
A third amplifier 20 that receives an acoustic signal including wind noise from the second unidirectional microphone 19 and amplifies the signal so that the signal processing of the next stage can be performed, and the acoustic amplified by the third amplifier 20 Among the signals, a third LPF 21 that passes a frequency band (200 Hz in the embodiment) mainly including a wind noise signal and a frequency band mainly including human voice among the acoustic signals amplified by the third amplifier 20 are used. A third HPF 22 to pass;
The signal in the frequency band including the sound that has passed through the first HPF 14 from the first unidirectional microphone 11 and the signal in the frequency band that includes the sound that has passed through the second HPF 18 from the bidirectional microphone 15 are added. A first computing unit 23, a frequency band signal including the sound that has passed through the second HPF 18, and a frequency band signal including the sound that has passed through the third HPF 22 from the second unidirectional microphone 19. , A second computing unit 24 for subtracting a signal in the frequency band including the voice that has passed through the first HPF 14 and a signal in the frequency band containing the voice of the second HPF 18, A fourth computing unit 26 that subtracts a signal in a frequency band including the sound that has passed through the second HPF 18 and a signal in a frequency band that includes the sound of the third HPF 22;
The wind noise removal circuit 31 adds the signal including the sound of the first unidirectional microphone 11 and the signal including the sound of the bidirectional microphone 15 added by the first arithmetic unit 23 to the wind sound removal circuit 31. A first mixer 27 for mixing the wind noise removal signal from which the components have been removed;
The wind noise removal circuit 31 adds the signal including the sound of the first unidirectional microphone 11 subtracted by the third arithmetic unit 25 and the signal including the sound of the bidirectional microphone 15 to the wind A second mixer 28 for mixing the wind noise removal signal from which the components have been removed;
The wind sound removal circuit 31 adds the signal including the sound of the bidirectional microphone 15 added by the second arithmetic unit 16 and the signal including the sound of the second unidirectional microphone 19 A third mixer 29 for mixing the wind noise removal signal from which the components have been removed;
The wind noise removal circuit 31 adds the signal including the sound of the bidirectional microphone 15 subtracted by the fourth computing unit 26 and the signal including the sound of the second unidirectional microphone 19 to the wind. A fourth mixer 30 for mixing the wind noise removal signal from which the components have been removed;
It comprises a wind noise removal circuit 31 that removes wind noise.
Here, the output of the first mixer 27 is FL (Front Left), the output of the second mixer 28 is FR (Front Rear), the output of the third mixer 29 is RL (Rear Left), the fourth The output of the mixer 30 is RR (Rear Right).

The wind noise removal circuit 31 mainly uses the signal from the second LPF 17 that has passed the frequency band mainly including the wind noise signal of the bidirectional microphone 15 and the wind noise signal of the second unidirectional microphone 19. A fifth computing unit 32 (first subtracting means) for subtracting the signal from the third LPF 21 that has passed the frequency band included in
A frequency mainly including the wind noise signal of the first unidirectional microphone 11 and the signal from the first LPF 13 that has passed the frequency band mainly including the wind noise signal of the first unidirectional microphone 11. A sixth computing unit 33 (second subtracting means) for subtracting the signal from the third LPF 21 that has passed through the band;
A frequency mainly including the wind noise signal of the first unidirectional microphone 11 and the signal from the first LPF 13 that has passed the frequency band mainly including the wind noise signal of the first unidirectional microphone 11. A seventh computing unit 34 (adding means) for adding the signal from the third LPF 21 that has passed through the band;
The attenuator having an attenuation of about 15 to 20 dB is attenuated by attenuating a signal obtained by subtracting the wind noise signal of the second unidirectional microphone 19 from the wind noise signal of the bidirectional microphone 15 obtained by the fifth arithmetic unit 32. (ATT) 35, a first full-wave rectifier 36 (first rectifying means) for full-wave rectifying the attenuated signal to obtain a predetermined voltage,
A signal obtained by subtracting the wind noise of the second unidirectional microphone 19 from the wind noise of the first unidirectional microphone 11 obtained by the sixth computing unit 33 is full-wave rectified to obtain a predetermined voltage. A second full-wave rectifier 37 (second rectifier);
A determination unit 38 (determination means) that compares the voltage signal obtained by the first full-wave rectifier 36 with the voltage signal obtained by the second full-wave rectifier 37;
The output signal of the seventh arithmetic unit 34 is connected to the first input terminal 39a, the output signal of the seventh arithmetic unit 34 is input to the second input terminal 39b, and the notch filter 40 having a center frequency of 200 Hz is passed through. A switch (SW) 39 (switch means) that connects the selected signals with the output signal of the determiner 38;
A 1/2 attenuator 41 (attenuating means) that is connected to the output terminal of the switch (SW) 39, attenuates the wind noise elimination signal, and attenuates the attenuation to about half of 15 to 20 dB;
Consists of
The wind noise removal signal obtained by removing the wind sound, which is the output signal of the ½ attenuator 41, is mixed with the surround signals of the fifth to eighth operators 27, 28, 29, and 30.

In the circuit having such a configuration, first, the acoustic signals from the first and second unidirectional microphones 11 and 19 and the bidirectional microphone 15 are amplified by the first to third amplifiers 12, 16 and 20. After that, the first to third HPFs 14, 18, and 22 and the first to third LPFs 13, 17, and 21 separate the bands.
Since the outputs of the first to third HPFs 14, 18 and 22 have a stereo feeling, they are input to an arithmetic circuit including the first to fourth arithmetic units 23, 24, 25 and 26 in the subsequent stage.
The outputs of the first to third LPFs 13, 17, and 21 include an audio signal and a wind noise signal, and the audio signal is correlated, but the wind noise signal is not correlated.
An addition signal between the first and second unidirectional microphones 11, 19, that is, a signal that inputs the output signal of the seventh arithmetic unit 34 as it is to the switch (SW) 39, and the seventh arithmetic unit 34 A signal obtained by further passing the output signal through the notch filter 40 is switched to a signal input to the switch (SW) 39. This switching is a full-wave rectification of the output signal of the sixth computing unit 33 obtained by subtracting the signal of the second LPF 17 of the bidirectional microphone 15 and the signal of the third LPF 21 of the second unidirectional microphone 19. The output of the fifth arithmetic unit 32 that subtracts the voltage obtained in this way, the output signal of the second LPF 17 of the bidirectional microphone 15 and the output signal of the third LPF 21 of the second unidirectional microphone 19. The signal is attenuated by the attenuator 35, and the determination unit 38 compares the full-wave rectified voltage.
In short, the determination by the determination unit 38 is the same as the voltage obtained from the signal obtained by subtracting the sound noise signal of the bi-directional microphone 15 and the second unidirectional microphone 19 and the first and the second having the same property. When it is determined that there is no wind noise signal by comparing the voltage obtained from the signal obtained by subtracting the sound noise signal with the two unidirectional microphones 11 and 19, the first and second single microphones 11 and 19 When a signal obtained by adding the sound noise signals of the directional microphones 11 and 19 by the seventh calculator 34 is selected and it is determined that there is a wind noise signal, the first and second unidirectional microphones 11 and 19 A wind noise removal signal is obtained by selecting a signal obtained by adding the sound noise signal to the seventh arithmetic unit 34 and further passing the signal through the notch filter 40.

  Since the wind noise signal of the bidirectional microphone 15 is larger than the wind noise signals of the first and second unidirectional microphones 11 and 19, the second LPF 17 of the bidirectional microphone 15 is not used as an audio signal. Used as a wind noise detection sensor.

The fifth arithmetic unit 32 subtracts the output signal of the second LPF 17 of the bidirectional microphone 15 and the output signal of the third LPF 21 of the second unidirectional microphone 19. If there is wind noise, the wind noise signal is uncorrelated and appears in the subtraction output. This is full-wave rectified by a first full-wave rectifier 36 through an attenuator (ATT) 35, converted into a DC voltage, and input to one terminal of a determiner 38.
The output signals of the first and third LPFs 13 and 21 of the first and second unidirectional microphones 11 and 19 having the same property are subtracted by the sixth arithmetic unit 33, and the second full-wave rectifier 37 performs direct current. The voltage is converted to a voltage and input to the other input terminal of the determination unit 38.

The determiner 38 is a comparator, and a voltage obtained from the wind noise signal of the bidirectional microphone 15 and the second unidirectional microphone 19 input from one input terminal and input from the other input terminal. By comparing the voltage obtained from the wind noise signals of the first and second unidirectional microphones 11 and 19, the generation of wind is detected, and the output terminal is made positive.
When the output terminal becomes positive, it is determined that there is a wind noise signal, and the switch (SW) 39 is controlled so that the second input terminal 39b and the output terminal are connected. Wind noise removal signal.

  When the output terminal is negative, it is determined that there is no wind noise signal, it is determined that no wind is generated, and the switch (SW) 39 is controlled to connect the first input terminal 39a and the output terminal. Then, the signal calculated by the seventh calculator 34 is selected as a wind noise removal signal.

  In this way, a voltage is generated by rectifying a signal obtained by subtracting the signal of the band frequency including the wind noise signal between the two first and second unidirectional microphones 11 and 19, and the bidirectionality is obtained. A voltage obtained by rectifying a signal obtained by subtracting the band frequency signal including the wind noise signal of the microphone 15 and the signal of the band frequency including the wind noise signal of any of the first or second unidirectional microphones 11 and 19 is rectified. When it is determined that there is no wind among the signals for determining the presence or absence of wind, these are added by the seventh arithmetic unit 34 between the two first and second unidirectional microphones 11 and 19. The signal is passed as it is and mixed with the surround signal. When it is determined that there is a wind, the signals are added by the seventh arithmetic unit 34 between the two first and second unidirectional microphones 11 and 19. The signal further passes through the notch filter 40 By narrowing down to a narrow-band frequency signal with a wind-specific center frequency, the signal is mixed with the surround signal, so that the wind noise can be reduced to match the wind noise. It becomes possible.

  Next, a wind noise reduction apparatus according to a second embodiment will be described with reference to the drawings.

  As shown in FIG. 2, the wind noise reduction apparatus of the second embodiment is the same as the circuit shown in the wind noise reduction apparatus of the first embodiment, and the only difference is that the wind noise removal circuit is different. The same parts are described with the same reference numerals, the description thereof is omitted, and only the wind noise removal circuit will be described.

The wind noise removal circuit 31A mainly uses the signal from the second LPF 17 that has passed the frequency band mainly including the wind noise signal of the bidirectional microphone 15 and the wind noise signal of the second unidirectional microphone 19. A fifth computing unit 32 (first subtracting means) for subtracting the signal from the third LPF 21 that has passed the frequency band included in
A frequency mainly including the wind noise signal of the first unidirectional microphone 11 and the signal from the first LPF 13 that has passed the frequency band mainly including the wind noise signal of the first unidirectional microphone 11. A sixth computing unit 33 (second subtracting means) for subtracting the signal from the third LPF 21 that has passed through the band;
A frequency mainly including the wind noise signal of the first unidirectional microphone 11 and the signal from the first LPF 13 that has passed the frequency band mainly including the wind noise signal of the first unidirectional microphone 11. A seventh computing unit 34 (adding means) for adding the signal from the third LPF 21 that has passed through the band;
The attenuator having an attenuation of about 15 to 20 dB is attenuated by attenuating a signal obtained by subtracting the wind noise signal of the second unidirectional microphone 19 from the wind noise signal of the bidirectional microphone 15 obtained by the fifth arithmetic unit 32. (ATT) 35, a first full-wave rectifier 36 (first rectifying means) for full-wave rectifying the attenuated signal to obtain a predetermined voltage,
A signal obtained by subtracting the wind noise of the second unidirectional microphone 19 from the wind noise of the first unidirectional microphone 11 obtained by the sixth computing unit 33 is full-wave rectified to obtain a predetermined voltage. A second full-wave rectifier 37 (second rectifier);
A determination unit 38 (determination means) that compares the voltage signal obtained by the first full-wave rectifier 36 with the voltage signal obtained by the second full-wave rectifier 37;
The output signal of the seventh arithmetic unit 34 is connected to the first input terminal 39a, the output signal of the seventh arithmetic unit 34 is input to the second input terminal 39b, and the signal passes through the high pass filter (HPF) 42. , And a switch (SW) 39 (switch means) that performs switching by an output signal of the determiner 38;
A 1/2 attenuator 41 (attenuating means) that is connected to the output terminal of the switch (SW) 39, attenuates the wind noise elimination signal, and attenuates the attenuation to about half of 15 to 20 dB;
Consists of
The wind noise removal signal obtained by removing the wind sound, which is the output signal of the 1/2 attenuator 41, is mixed with the signals of the fifth to eighth operators 27, 28, 29, and 30, and surrounds FL, FR, RL, and RR. The signal is obtained.

In the circuit having such a configuration, first, the acoustic signals from the first and second unidirectional microphones 11 and 19 and the bidirectional microphone 15 are amplified by the first to third amplifiers 12, 16 and 20. After that, the first to third HPFs 14, 18, and 22 and the first to third LPFs 13, 17, and 21 separate the bands.
Since the outputs of the first to third HPFs 14, 18 and 22 have a stereo feeling, they are input to an arithmetic circuit including the first to fourth arithmetic units 23, 24, 25 and 26 in the subsequent stage.
The outputs of the first to third LPFs 13, 17, and 21 include an audio signal and a wind noise signal, and the audio signal is correlated, but the wind noise signal is not correlated.
An addition signal between the first and second unidirectional microphones 11, 19, that is, a signal that inputs the output signal of the seventh arithmetic unit 34 as it is to the switch (SW) 39, and the seventh arithmetic unit 34 A signal obtained by passing the output signal through the notch filter 40 is input to the switch (SW) 39. In this switching, the output signal of the sixth arithmetic unit 33 obtained by subtracting the signal of the second LPF 17 of the bidirectional microphone 15 and the signal of the third LPF 21 of the second unidirectional microphone 19 is full-wave rectified. And the output signal of the fifth arithmetic unit 32 that subtracts the output signal of the second LPF 17 of the bidirectional microphone 15 and the output signal of the third LPF 21 of the second unidirectional microphone 19. Is attenuated by the attenuator 35 and is compared with a full-wave rectified voltage.

  The determination by the determination unit 38 is basically the same as the voltage obtained from the signal obtained by subtracting the sound noise signal of the bidirectional microphone 15 and the second unidirectional microphone 19 by the fifth calculator 32. The wind noise signal is obtained by comparing the voltage obtained from the signal obtained by subtracting the sound noise signal with the first and second unidirectional microphones 11 and 19 having the property by the sixth computing unit 33. When it is determined that there is no wind noise signal, a signal obtained by adding the sound noise signals of the first and second unidirectional microphones 11 and 19 to the seventh arithmetic unit 34 is selected. A signal obtained by adding the sound noise signals of the first and second unidirectional microphones 11 and 19 by the seventh calculator 34 and further passing the high-pass filter 42 is selected to obtain a wind noise removal signal. .

  Since the wind noise signal of the bidirectional microphone 15 is larger than the wind noise signals of the first and second unidirectional microphones 11 and 19, the second LPF 17 of the bidirectional microphone 15 is not used as an audio signal. Used as a wind noise detection sensor.

The fifth arithmetic unit 32 subtracts the output signal of the second LPF 17 of the bidirectional microphone 15 and the output signal of the third LPF 21 of the second unidirectional microphone 19. If there is wind noise, the wind noise signal is uncorrelated and appears in the subtraction output. This is full-wave rectified by a first full-wave rectifier 36 through an attenuator (ATT) 35, converted into a DC voltage, and input to one terminal of a determiner 38.
The output signals of the first and third LPFs 13 and 21 of the first and second unidirectional microphones 11 and 19 having the same property are subtracted by the sixth arithmetic unit 33, and the second full-wave rectifier 37 performs direct current. The voltage is converted to a voltage and input to the other input terminal of the determination unit 38.

The determiner 38 is a comparator, and a voltage obtained from the wind noise signal of the bidirectional microphone 15 and the second unidirectional microphone 19 input from one input terminal and input from the other input terminal. By comparing the voltage obtained from the wind noise signals of the first and second unidirectional microphones 11 and 19, the generation of wind is detected, and the output terminal is made positive.
When the output terminal becomes positive, it is determined that there is a wind noise signal, and the switch (SW) 39 is controlled so that the second input terminal 39b and the output terminal are connected, and the high-pass filter (HPF) 42 is passed. This signal becomes the wind noise elimination signal.

  When the output terminal is negative, it is determined that no wind is generated, and the switch (SW) 39 is controlled so that the first input terminal 39a and the output terminal are connected to each other. The signal calculated at 34 is selected as a wind noise removal signal.

  As described above, when it is determined that there is wind noise, the wind noise signals from the first and second unidirectional microphones 11 and 19 having the same property are passed through the high-pass filter (HPF) 42 and only in a predetermined band. The signal that has passed through is taken out as a wind noise elimination signal and mixed with the FL, FR, RL, and RR surround signals of the final channel to obtain a surround signal that does not significantly affect the stereo sense of wind noise reduction It can be done.

  Next, a wind noise reduction apparatus according to a third embodiment will be described with reference to the drawings.

  As shown in FIG. 3, the wind noise reducing device of the third embodiment is the same as the circuit shown in the wind noise reducing device of the first embodiment, and the only difference is that the wind noise removing circuit is different. The same parts are described with the same reference numerals, the description thereof is omitted, and only the wind noise removal circuit will be described.

The wind noise removal circuit 31B mainly uses the signal from the second LPF 17 that has passed the frequency band mainly including the wind noise signal of the bidirectional microphone 15 and the wind noise signal of the second unidirectional microphone 19. A fifth computing unit 32 (first subtracting means) for subtracting the signal from the third LPF 21 that has passed the frequency band included in
A frequency mainly including the wind noise signal of the first unidirectional microphone 11 and the signal from the first LPF 13 that has passed the frequency band mainly including the wind noise signal of the first unidirectional microphone 11. A sixth computing unit 33 (second subtracting means) for subtracting the signal from the third LPF 21 that has passed through the band;
A frequency mainly including the wind noise signal of the first unidirectional microphone 11 and the signal from the first LPF 13 that has passed the frequency band mainly including the wind noise signal of the first unidirectional microphone 11. A seventh computing unit 34 (adding means) for adding the signal from the third LPF 21 that has passed through the band;
A signal obtained by subtracting the wind noise signal of the second unidirectional microphone 19 from the wind noise signal of the bidirectional microphone 15 obtained by the fifth arithmetic unit 32 is attenuated, and the attenuation is about 6 dB. An attenuator (ATT) 35A when the signal is strong, a first-A full-wave rectifier 36A (first rectifier) that obtains a predetermined voltage by full-wave rectifying the attenuated signal,
A signal obtained by subtracting the wind noise signal of the second unidirectional microphone 19 from the wind noise signal of the bidirectional microphone 15 obtained by the fifth arithmetic unit 32 is attenuated, and the attenuation is about 3 dB. An attenuator (ATT) 35B when the signal is weak, a 1B full-wave rectifier 36B (first rectifier) that obtains a predetermined voltage by full-wave rectifying the attenuated signal,
A signal obtained by subtracting the wind noise of the second unidirectional microphone 19 from the wind noise of the first unidirectional microphone 11 obtained by the sixth computing unit 33, that is, the signal when there is no wind is the full wave. A second full-wave rectifier 37 (second rectifier) that rectifies and obtains a predetermined voltage;
Three signals of the voltage signal obtained by the 1A full-wave rectifier 36A, the voltage signal obtained by the 1B full-wave rectifier 36B, and the voltage signal obtained by the second full-wave rectifier 37 are obtained. In comparison, a determination unit 38 (determination means) that outputs a signal when the wind is strong, a signal when the wind is weak, and a signal when there is no wind to the output terminal;
The output signal of the seventh arithmetic unit 34 is connected to the first input terminal 39a, the output signal of the seventh arithmetic unit 34 is input to the second input terminal 39b, and the signal via the notch filter 40 is connected. ,
A switch for inputting the output signal of the seventh arithmetic unit 34 to the third input terminal 39b, connecting the signal through the high pass filter (HPF) 42, and controlling the switching of the three by the output signal of the determination unit 38 (SW) 39 (switch means);
A 1/2 attenuator 41 (attenuating means) that is connected to the output terminal of the switch (SW) 39, attenuates the wind noise elimination signal, and attenuates the attenuation to about half of 15 to 20 dB;
Consists of
The wind noise removal signal obtained by removing the wind sound, which is the output signal of the ½ attenuator 41, is mixed with the surround signals of the fifth to eighth operators 27, 28, 29, and 30.

In the circuit having such a configuration, first, the acoustic signals from the first and second unidirectional microphones 11 and 19 and the bidirectional microphone 15 are amplified by the first to third amplifiers 12, 16 and 20. After that, the first to third HPFs 14, 18, and 22 and the first to third LPFs 13, 17, and 21 separate the bands.
Since the outputs of the first to third HPFs 14, 18 and 22 have a stereo feeling, they are input to an arithmetic circuit including the first to fourth arithmetic units 23, 24, 25 and 26 in the subsequent stage.
The outputs of the first to third LPFs 13, 17, and 21 include an audio signal and a wind noise signal, and the audio signal is correlated, but the wind noise signal is not correlated.
The addition signal between the first and second unidirectional microphones 11 and 19, that is, a signal (the signal when there is no wind) that is input to the switch SW as it is as the output signal of the seventh computing unit 34, A signal obtained by passing the output signal of the computing unit 34 through the notch filter 40 (a signal when the wind is weak), and a signal obtained by passing the output signal of the seventh computing unit 34 through the high pass filter (HPF) 40B (when the wind is strong) The switch (SW) 39 is switched based on the signal of the output terminal from the determiner 38.

  The determination by the determination unit 38 is based on a voltage obtained by full-wave rectification of a signal when the first and second unidirectional microphones 11 and 19 are subtracted from each other (a signal when there is no wind), and a second unidirectional Subtracting the signal of the band frequency including the wind noise signal obtained by the directional microphone 19 and the bidirectional microphone 15, and the full-wave rectification of the signal obtained by attenuating the subtracted signal with the attenuator 35 </ b> B having a smaller attenuation (3 dB) And subtracting the band frequency signal including the wind noise signal obtained by the second unidirectional microphone 19 and the bi-directional microphone 15 and further subtracting the subtracted signal. By comparing the three voltages (the signal when the wind is strong) of the signal attenuated by the attenuator 35A having a large attenuation (6 dB), the current wind noise state is no wind, Can be judged to be weak or windy By outputting the signals, you can switch control the switch 39A in three stages.

  When it is determined that there is no wind, the signal obtained by adding the sound and noise signals of the first and second unidirectional microphones 11 and 19 by the seventh calculator 34 is passed as it is, and it is determined that the wind is weak. Sometimes, the signal obtained by adding the sound noise signals of the first and second unidirectional microphones 11 and 19 by the seventh computing unit 34 is further passed through the notch filter 40, and it is determined that the wind is strong. In this case, a signal obtained by adding the sound noise signals of the first and second unidirectional microphones 11 and 19 by the seventh arithmetic unit 34 is further passed through a high-pass filter (HPF) 40B.

  The signal thus switched is attenuated by the attenuator 41 and mixed with the surround signal by the first to fourth mixers 27, 28, 29, and 30 as a wind noise elimination signal.

  Next, a wind noise reduction method and a wind noise reduction apparatus according to a fourth embodiment will be described with reference to the drawings.

  The wind noise reduction apparatus that can embody the wind noise reduction method of the fourth embodiment is the same as the circuit shown in the wind noise reduction apparatus of the first embodiment as shown in FIG. Since the wind noise removal circuit is different, the same parts are described with the same reference numerals and the description thereof is omitted, and only the wind noise removal circuit is described.

The wind noise removal circuit 31C mainly uses the signal from the second LPF 17 that has passed the frequency band mainly including the wind noise signal of the bidirectional microphone 15 and the wind noise signal of the second unidirectional microphone 19. A fifth computing unit 32 (first subtracting means) for subtracting the signal from the third LPF 21 that has passed the frequency band included in
A frequency mainly including the wind noise signal of the first unidirectional microphone 11 and the signal from the first LPF 13 that has passed the frequency band mainly including the wind noise signal of the first unidirectional microphone 11. A sixth computing unit 33 (second subtracting means) for subtracting the signal from the third LPF 21 that has passed through the band;
A frequency mainly including the wind noise signal of the first unidirectional microphone 11 and the signal from the first LPF 13 that has passed the frequency band mainly including the wind noise signal of the first unidirectional microphone 11. A seventh computing unit 34 (adding means) for adding the signal from the third LPF 21 that has passed through the band;
A signal obtained by subtracting the wind noise signal of the second unidirectional microphone 19 from the wind noise signal of the bidirectional microphone 15 obtained by the fifth computing unit 32 is attenuated, and the attenuation is about 6 dB (the wind is strong). Attenuator (ATT) 35A, a 1A full-wave rectifier 36A (first rectifying means) for full-wave rectifying the attenuated signal to obtain a predetermined voltage,
A signal obtained by subtracting the wind noise signal of the second unidirectional microphone 19 from the wind noise signal of the bidirectional microphone 15 obtained by the fifth computing unit 32 is attenuated, and the attenuation is about 3 dB (the wind is weak). Attenuator (ATT) 35B, and a 1B full-wave rectifier 36B (first rectifier) that obtains a predetermined voltage by full-wave rectifying the attenuated signal;
A signal obtained by subtracting the wind noise of the second unidirectional microphone 19 from the wind noise of the first unidirectional microphone 11 obtained by the sixth computing unit 33 (when there is no wind) is full-wave rectified. A second full-wave rectifier 37 (second rectifier) for obtaining a predetermined voltage
Three signals are obtained: a voltage signal obtained by the 1A full-wave rectifier 36, a voltage signal obtained by the 1A full-wave rectifier 36, and a voltage signal obtained by the second full-wave rectifier 37. A determination unit 38 (determination means) that outputs a determination of no wind, weak wind, and strong wind to an output terminal;
The output signal of the seventh arithmetic unit 34 is connected to the first input terminal 39a, the output signal of the seventh arithmetic unit 34 is input to the second input terminal 39b, and the signal via the notch filter 40 is connected. ,
The output signal of the seventh arithmetic unit 34 is input to the third input terminal 39c, the signal through the notch filter 40 and the high-pass filter (HPF) 42 is connected, and the three switching is the output signal of the determiner 38. Switch (SW) 39 (switch means) controlled by
A 1/2 attenuator 41 (attenuating means) that is connected to the output terminal of the switch (SW) 39, attenuates the wind noise elimination signal, and attenuates the attenuation to about half of 15 to 20 dB;
Consists of
The wind noise removal signal from which the wind sound that is the output signal of the ½ attenuator 41 is removed is mixed with the surround signal by the fifth to eighth mixers 27, 28, 29, and 30.

In the circuit having such a configuration, first, the acoustic signals from the first and second unidirectional microphones 11 and 19 and the bidirectional microphone 15 are amplified by the first to third amplifiers 12, 16 and 20. After that, the first to third HPFs 14, 18, and 22 and the first to third LPFs 13, 17, and 21 separate the bands.
Since the outputs of the first to third HPFs 14, 18 and 22 have a stereo feeling, they are input to an arithmetic circuit including the first to fourth arithmetic units 23, 24, 25 and 26 in the subsequent stage.
The outputs of the first to third LPFs 13, 17, and 21 include an audio signal and a wind noise signal, and the audio signal is correlated, but the wind noise signal is not correlated.
Addition signal between the first and second unidirectional microphones 11 and 19, that is, a signal that passes the output signal of the seventh computing unit 34 as it is (when there is no wind), the output of the seventh computing unit 34 A signal obtained by further passing the signal through the notch filter 40 (when the wind is weak), and a signal allowing the output signal of the seventh computing unit 34 to further pass through the notch filter and the high pass filter (HPF) (when the wind is strong). The type is switched by a switch (SW) 39.
This switching is a full-wave rectification of the output signal of the sixth computing unit 33 obtained by subtracting the signal of the second LPF 17 of the bidirectional microphone 15 and the signal of the third LPF 21 of the second unidirectional microphone 19. The fifth voltage is obtained by subtracting the output signal of the second LPF 17 of the bidirectional microphone 15 and the output signal of the third LPF 21 of the second unidirectional microphone 19 from the obtained voltage (when there is no wind). The output signal of the computing unit 32 is attenuated by the attenuator 35A and full-wave rectified voltage (when wind is strong), the output signal of the second LPF 17 of the bidirectional microphone 15 and the first output of the second unidirectional microphone 19 The output signal of the fifth arithmetic unit 32 that subtracts the output signal of the third LPF 21 is attenuated by the attenuator 35B, and the determination unit 38 compares the full-wave rectified voltage (when the wind is weak).

  The determination by the determination unit 38 is a voltage obtained by full-wave rectification of a signal obtained by subtracting the first and second unidirectional microphones 11 and 19 by the sixth arithmetic unit 33 (signal when there is no wind). The signal of the band frequency including the wind noise signal obtained by the second unidirectional microphone 19 and the bidirectional microphone 15 is subtracted by the fifth computing unit 32, and the subtracted signal is further reduced in attenuation amount. A voltage obtained by full-wave rectification of the signal attenuated by the (3 dB) attenuator 35B (a signal when the wind is weak), and the wind noise signal obtained by the second unidirectional microphone 19 and the bidirectional microphone 15 are included. A signal obtained by subtracting the signal of the band frequency by the fifth computing unit, and a signal obtained by full-wave rectifying the signal obtained by attenuating the subtracted signal by the attenuator 35A having a larger attenuation (6 dB) (signal when the wind is strong). Current voltage No's state wind wind is weak, can determine that the wind is strong, by outputting the signal, you can switch control the switch 39A in three stages.

  When it is determined that there is no wind, the signal obtained by adding the sound and noise signals of the first and second unidirectional microphones 11 and 19 by the seventh calculator 34 is passed as it is, and it is determined that the wind is weak. Sometimes, when the signal obtained by adding the sound noise signals of the first and second unidirectional microphones by the seventh computing unit 34 is further passed through the notch filter 40 and it is determined that the wind is strong, The signal obtained by adding the sound noise signals of the first and second unidirectional microphones by the seventh calculator 34 is further passed through the notch filter 40 and the high-pass filter (HPF) 40B.

  The signal thus switched is attenuated by the attenuator 41 and mixed with the surround signal by the first to fourth mixers 27, 28, 29, and 30 as a wind noise elimination signal.

  In a surround microphone composed of two unidirectional microphones and one bidirectional microphone, a difference between a band frequency signal including a wind noise signal between the two unidirectional microphones, a bidirectional microphone and a single microphone. The difference between the signal of the global frequency including the wind noise signal and the unidirectional microphone is rectified, and the presence or absence of wind is detected by comparing the rectified voltage. The signal added between the two directional microphones is mixed with the surround signal including the audio signal as a wind removal signal and the signal added between the two unidirectional microphones is further passed through the notch filter. Provided is a wind sound suggestion device in which a wind noise signal included in an audio signal input to a microphone is reduced by being mixed with a surround signal including an audio signal as a wind removal signal.

1 is a block diagram of a wind noise reducing apparatus according to a first embodiment of the present invention. It is a block diagram of the wind noise reduction apparatus of 2nd Example based on this invention. It is a block diagram of the wind noise reduction device of the 3rd example concerning the present invention. It is a block diagram of the wind noise reduction apparatus of the 4th Example concerning the present invention. It is a block diagram of the wind noise reduction apparatus in a prior art.

Explanation of symbols

11; first unidirectional microphone, 12; first amplifier, 13; first LPF, 14; first HPF, 15; bi-directional microphone, 16; second amplifier, 17; LPF, 18; second HPF, 19; second unidirectional microphone, 20; third amplifier, 21; third LPF, 22; third HPF, 23; 24; second calculator 25; third calculator 26; fourth calculator 27; first mixer 28; second mixer 29; third mixer 30; 4th mixer, 31; Wind sound removal circuit, 31A; Wind sound removal circuit, 31B; Wind sound removal circuit, 32; 5th computing unit, 33; 6th computing unit, 34; 7th computing unit 35; Attenuator (ATT), 35A; Attenuator, 35B; Attenuator, 36; First full-wave rectifier, 36A; 36B; 1B full-wave rectifier 37; second full-wave rectifier 38; decision unit 39; switch (SW) 39a; first input terminal 39b; second input terminal 39c; Third input terminal, 40; notch filter, 40B; HPF, 41; attenuator, 42; high-pass filter.

Claims (8)

A surround microphone comprising two first and second unidirectional microphones and one bidirectional microphone,
A first subtraction for subtracting a signal having a band frequency including a wind noise signal obtained by the second unidirectional microphone from a signal having a band frequency including a wind noise signal obtained by the bidirectional microphone. Means,
A band frequency signal including the wind noise signal obtained by the second unidirectional microphone is subtracted from a band frequency signal including the wind noise signal obtained by the first unidirectional microphone. A second subtracting means;
First rectifying means for attenuating and subtracting a subtraction signal obtained by the first subtracting means by a predetermined amount;
Second rectification means for rectifying the subtraction signal obtained by the second subtraction means;
A determination unit that compares the voltage obtained by the first rectification unit with the voltage obtained by the second rectification unit and outputs the presence or absence of wind noise;
Adding means for adding signals of band frequencies including wind noise signals obtained by the first and second unidirectional microphones;
When the determination means determines that there is no wind noise, the signal of the addition component obtained by the addition means is switched to pass as it is, or when the determination means determines that there is wind noise, it is obtained by the addition means. Switch means for switching the signal of the added component to pass the signal further passing through the notch filter;
The signal of the addition component obtained by the addition means switched by the switch means, or the signal obtained by further passing the signal of the addition component obtained by the addition means through a notch filter, Mixing means for mixing into a surround signal composed of a signal of a band frequency including an audio signal from a unidirectional microphone and a bidirectional microphone;
A wind noise reduction device comprising:   The wind noise reduction apparatus according to claim 1, further comprising an attenuation unit that attenuates the signal switched by the switch unit and supplies the signal to the mixing unit. A surround microphone comprising two first and second unidirectional microphones and one bidirectional microphone,
A first subtraction for subtracting a signal having a band frequency including a wind noise signal obtained by the second unidirectional microphone from a signal having a band frequency including a wind noise signal obtained by the bidirectional microphone. means,
A band frequency signal including the wind noise signal obtained by the second unidirectional microphone is subtracted from a band frequency signal including the wind noise signal obtained by the first unidirectional microphone. A second subtracting means;
First rectifying means for attenuating and subtracting a subtraction signal obtained by the first subtracting means by a predetermined amount;
Second rectification means for rectifying the subtraction signal obtained by the second subtraction means;
A determination unit that compares the voltage obtained by the first rectification unit with the voltage obtained by the second rectification unit and outputs the presence or absence of wind noise;
Adding means for adding signals of band frequencies including wind noise signals obtained by the first and second unidirectional microphones;
When the determination means determines that there is no wind noise, the signal of the addition component obtained by the addition means is switched to pass as it is, or when the determination means determines that there is wind noise, it is obtained by the addition means. Switch means for switching the signal of the added component further to pass the signal that has passed through the high-pass filter;
The signal of the addition component obtained by the addition means switched by the switch means or the signal of the addition component obtained by the addition means further passed through a high-pass filter is sent to the first and second signals. Mixing means for mixing into a surround signal composed of a signal of a band frequency including an audio signal from a unidirectional microphone and a bidirectional microphone;
A wind noise reduction device comprising:   4. The wind noise reduction device according to claim 3, further comprising an attenuating unit that attenuates the signal switched by the switch unit and supplies the signal to the mixing unit. A surround microphone comprising two first and second unidirectional microphones and one bidirectional microphone,
A first subtraction for subtracting a signal having a band frequency including a wind noise signal obtained by the second unidirectional microphone from a signal having a band frequency including a wind noise signal obtained by the bidirectional microphone. means,
A band frequency signal including the wind noise signal obtained by the second unidirectional microphone is subtracted from a band frequency signal including the wind noise signal obtained by the first unidirectional microphone. A second subtracting means;
First rectification means for attenuating the subtraction signal obtained by the first subtraction means through each of two types of attenuators having different attenuation amounts and rectifying each;
Second rectification means for rectifying the subtraction signal obtained by the second subtraction means;
A determination means for comparing the voltage obtained by the first rectification means and the voltage obtained by the second rectification means and outputting the strength of the wind and the presence or absence of wind;
Adding means for adding signals of band frequencies including wind noise signals obtained by the first and second unidirectional microphones;
When the determination means determines that there is no wind noise, the addition component signal obtained by the addition means is switched to pass as it is, or when the determination means determines that there is weak wind noise, the addition means obtains it. The added component signal is further switched to pass the signal that has passed through the notch filter, or when the determination means determines that there is strong wind noise, the addition component signal obtained by the addition means is further passed through. Switch means for switching to pass the signal passed through the filter;
The signal of the addition component obtained by the addition means switched by the switch means, or the signal of the addition component obtained by the addition means further passed through a notch filter, or obtained by the addition means A signal obtained by further passing a high-pass filter through the addition component signal is mixed with a surround signal composed of a signal of a band frequency including audio signals from the first and second unidirectional microphones and the bidirectional microphone. Mixing means to
A wind noise reduction device comprising:   6. The wind noise reduction device according to claim 5, further comprising an attenuation unit that attenuates the signal switched by the switch unit and supplies the signal to the mixing unit. A surround microphone comprising two first and second unidirectional microphones and one bidirectional microphone,
A first subtraction for subtracting a signal having a band frequency including a wind noise signal obtained by the second unidirectional microphone from a signal having a band frequency including a wind noise signal obtained by the bidirectional microphone. means,
A band frequency signal including the wind noise signal obtained by the second unidirectional microphone is subtracted from a band frequency signal including the wind noise signal obtained by the first unidirectional microphone. A second subtracting means;
First rectification means for attenuating the subtraction signal obtained by the first subtraction means through each of two types of attenuators having different attenuation amounts and rectifying each;
Second rectification means for rectifying the subtraction signal obtained by the second subtraction means;
A determination means for comparing the voltage obtained by the first rectification means and the voltage obtained by the second rectification means and outputting the strength of the wind and the presence or absence of wind;
Adding means for adding signals of band frequencies including wind noise signals obtained by the first and second unidirectional microphones;
When the determination means determines that there is no wind noise, the addition component signal obtained by the addition means is switched to pass as it is, or when the determination means determines that there is weak wind noise, the addition means obtains it. The added component signal is further switched to pass the signal that has passed through the notch filter, or when the determination means determines that there is strong wind noise, the addition component signal obtained by the addition means is further notched. Switch means for switching to pass the signal that has passed through the filter and the high-pass filter;
The signal of the addition component obtained by the addition means switched by the switch means, or the signal of the addition component obtained by the addition means further passed through a notch filter, or obtained by the addition means A signal obtained by further passing a notch filter and a high-pass filter to the signal of the addition component, and comprising a band frequency signal including audio signals from the first and second unidirectional microphones and the bidirectional microphone. Mixing means for mixing into the signal;
A wind noise reduction device comprising:   The wind noise reduction device according to claim 7, further comprising an attenuation unit that attenuates the signal switched by the switch unit and supplies the signal to the mixing unit.

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