JPH05308696A - Wind noise sensor - Google Patents

Abstract

PURPOSE:To detect the presence or absence of wind and the velocity of the wind by providing with a bidirectional microphone and a discrimination section discriminating the wind velocity by receiving the output of the bidirectional microphone. CONSTITUTION:The wind noise sensor is provided with a wind noise sensor 40, two similar microphones 41 and 42 arranged nearby, a wind screen provided on the microphone 41, a wind noise increase/decrease means 43 consisting of projections generating turbulence, and a discrimination section 44 discriminating the wind intensity by receiving the output U41 of the microphone 41 and the output U42 of the microphone 42. In this case, sound wave little affects the wind noise increase/decrease means 43, but the wind makes the output U41 and the output U42 to be different by the wind noise increase/decrease means 43. Thus, the wind is detected without affected by the sound wave.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microphone device having a wind noise suppressing function for automatically cutting a low frequency range with a filter or changing directivity in accordance with wind strength. The present invention relates to a wind noise sensor used for detecting strength.

[0002]

2. Description of the Related Art When a microphone device is used in a windy place such as outdoors, wind noise caused by the wind is mixed in with the signal and the recording quality is deteriorated. Therefore, attempts have been made to detect wind and suppress wind noise of the microphone device by electrical processing. To effectively suppress wind noise,
Along with the suppression method, the wind noise detection method is important. Hereinafter, a conventional example of the wind noise sensor will be described.

As a first conventional example, there is an anemometer using a heat ray or a thermistor as a sensor. This utilizes the property that the electrical resistance of the sensor changes depending on the wind speed.
The response speed is proportional to the heat capacity of the sensor unit. But,
Since the heat capacity cannot be made so small, there is a problem that the response speed is generally slow. There is also a problem that the smaller the heat capacity, the higher the cost.

In order to solve the above problems, there is a microphone using a sensor.

For example, as a second conventional example, focusing on the fact that the energy of wind noise is concentrated in the low frequency range, 1
There is a method of detecting wind by using low-range energy and high-range energy of the output of each microphone (see, for example, JP-A-63-308499).

FIG. 7 is a block diagram showing the configuration of the second conventional example. In FIG. 7, 71 is a microphone and 72
Is a bass pass filter for extracting the bass component of the output X7 of the microphone 71, and 73 is the output X of the microphone 71.
7 is a treble band pass filter for extracting the treble band component, 74 is a first level detector for detecting the level of the output F71 of the bass band pass filter 72, and 75 is a treble band pass filter 73.
Second level detector for detecting the level of the output F72 of
Reference numeral 76 is a determination unit that compares the output L71 of the first level detector 74 and the output L72 of the second level detector 75 to determine the strength of the wind. The above is the wind noise of the portion 70 surrounded by the broken line. It constitutes a sensor. 77 is the output C7 of the determination unit 76.
Is a wind noise removing unit that removes wind noise from the output X7 of the microphone 71 and outputs the output Y7.

The operation of the wind noise sensor configured as described above will be described below with reference to FIG. The output X7 of the microphone 71 is a low-pass filter 72.
The bass range component F71 and the treble range component F72 are taken out by the treble range pass filter 73 and the treble range pass filter 73, respectively. The low range component F71 is set to the level L by the first level detector 74.
71, on the other hand, the level L72 of the treble range component F72 is detected by the first level detector 75. The determination unit 76 determines the level L71 of the low range and the level L72 of the high range.
And outputs the control signal C7 to the wind noise eliminator. Since the energy of wind noise is concentrated in the low sound range, the ratio of the low sound range level L71 to the high sound range level L72 changes depending on the wind strength, and the wind strength can be detected.

However, the above-mentioned configuration has a problem that the same operation as in the case of wind is performed even for a sound having a large bass energy.

Similarly, as a third conventional example, there is a method in which one microphone is used to detect the wind by comparing the low range energy and the total range energy of the output (for example, a special feature). (See Japanese Laid-Open Publication No. 63-309097).

FIG. 8 is a block diagram showing the configuration of the third conventional example. In FIG. 8, 81 is a microphone and 82
Is a bass pass filter for extracting the bass component of the output X8 of the microphone 81, and 83 is the output X of the microphone 81.
8 is a full range filter for extracting the full range components, 84 is a first level detector for detecting the level of the output F81 of the low range filter 82, and 85 is a full range filter 83.
A second level detector for detecting the level of the output F82 of
Reference numeral 86 is a determination unit that compares the output L81 of the first level detector 84 and the output L82 of the second level detector 85 to determine the strength of the wind. The above is the wind noise of the portion 80 surrounded by the broken line. It constitutes a sensor. 87 is an output C8 of the determination unit 86
Is a wind noise removing unit that removes wind noise from the output X8 of the microphone 81 and outputs the output Y8.

In the third conventional example, the treble band pass filter 73, which constitutes the second conventional example, is only replaced by the all-tone range filter 83. Therefore, the operation of the second conventional example is almost the same as that of the second conventional example.

There are the following methods for solving the problems of the above-mentioned second and third conventional examples.

The fourth conventional example focuses on the fact that a unidirectional microphone has a higher sensitivity in the low frequency range to the wind than an omnidirectional microphone, so that a unidirectional microphone output and an omnidirectional microphone output are provided. The wind is detected by comparing (for example, Japanese Patent Laid-Open No. 1-39192).
See JP-A-1-39193, JP-A-1-39194, and JP-A-1-39195).

FIG. 9 is a block diagram showing the configuration of the fourth conventional example. In FIG. 9, 91 is an omnidirectional microphone, 92 is a unidirectional microphone, 93 is a first low-pass filter that extracts the low-frequency component of the output X91 of the omnidirectional microphone 91, and 94 is a unidirectional microphone. A second low-pass filter for extracting the low-pass component of the output X92 of 92, and 95 for the first low-pass filter 93.
First level detector for detecting the level of the output F91 of
Reference numeral 96 denotes a second level detector for detecting the level of the output F92 of the second low pass filter 96, and reference numeral 97 denotes the output L91 of the first level detector 95 and the output L92 of the second level detector 96. The determination unit for comparing and determining the strength of the wind constitutes the wind noise sensor of the portion 90 surrounded by the broken line. 98 is controlled by the output C9 of the determination unit 97,
Wind noise is removed using output X91 of omnidirectional microphone 91 and output of unidirectional microphone 92, and output Y
This is a wind noise eliminator that outputs 9.

The operation of the wind noise sensor constructed as above will be described below. The on-axis frequency sensitivities of the omnidirectional microphone 91 and the unidirectional microphone 92 to the sound waves are set to be the same in advance. Therefore, since the unidirectional microphone 92 has a directivity, the output X9 of the unidirectional microphone 92 is irrelevant to the sound source at a normal distance regardless of the frequency.
2 is not at least greater than the output X91 of the omnidirectional microphone 91. On the other hand, the unidirectional microphone 92 has higher bass sensitivity than the omnidirectional microphone 91 with respect to the wind.
The output X92 of 2 is the output X9 of the omnidirectional microphone 91.
It becomes larger than 1. Therefore, there is no problem such as the second and third conventional examples that malfunctions with respect to a sound having a large bass energy.

[0016]

However, in the configuration of the fourth conventional example, since the relative sensitivity of the unidirectional microphone and the omnidirectional microphone to the wind is different, the presence or absence of the wind can be detected. It is difficult to detect the strength of the.

In view of the above problems, the present invention provides a wind noise sensor which has a fast response speed, is inexpensive, and can detect not only the presence or absence of the wind but also the strength of the wind without malfunction even with a sound source having an excessive bass range. Is provided.

[0018]

In order to achieve this object, a wind noise sensor of the present invention comprises a bidirectional microphone and a determination unit for receiving the output of the bidirectional microphone and determining the strength of the wind. It is equipped with and.

As another means, two microphones of the same type, which are arranged close to each other, a subtraction unit for subtracting the outputs of the two microphones, and an output of the subtraction unit are used to determine the wind strength. And a determination unit that does.

Further, as another means, two microphones of the same type, which are closely arranged, a wind noise increasing / decreasing means provided in one or both of the two microphones, and outputs of the two microphones are received. And a determination unit that determines the strength of the wind. Here, the determining unit subtracts the output of the two microphones, or
It is effective to judge the wind strength using relative values.

[0021]

According to the present invention, with the above-described structure, the response speed is fast, the cost is low, and the sound intensity of the wind as well as the presence or absence of the wind can be detected without malfunction even with the sound source having the excessive bass range.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A wind noise sensor according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of a wind noise sensor according to the first embodiment of the present invention. In FIG. 1, 10 is a wind noise sensor, 1 is a bidirectional microphone,
Reference numeral 2 is a determination unit that receives the output U1 of the bidirectional microphone 1 and determines the strength of the wind. C1 is an output of the determination unit 2 and is a control signal of the wind noise removal unit 3. X1 and Y1 are an input signal and an output signal to the wind noise eliminator 3, respectively.

The operation of the wind noise sensor constructed as above will be described below. The wind noise sensitivity of the bidirectional microphone 1 has a characteristic that it becomes higher by 6 dB / octave toward the bass range than the axial sound pressure sensitivity for plane wave sound waves. Further, as described above, the energy of wind noise is concentrated in the low sound range. Therefore,
Due to the characteristics of both of them, by monitoring the energy of the output U1 of the bidirectional microphone 1 particularly in the low frequency range, the influence of sound waves can be reduced and only the wind can be detected. Further, if the determination standard for the wind strength of the determination unit 2 is set in advance according to the wind strength, the wind strength can be determined. Then, the output C1 of the determination unit 2 can control the wind noise removal unit 3 according to the strength of the wind.

As described above, according to this embodiment, the response speed is increased by providing the bidirectional microphone and the determination unit for receiving the output of the bidirectional microphone and determining the strength of the wind. In addition, it is possible to detect not only the presence or absence of the wind but also the strength of the wind at a low price without causing a malfunction even with a sound source having an excessive bass range.

A second embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a block diagram showing the configuration of the wind noise sensor according to the second embodiment of the present invention. In FIG. 2, 20 is a wind noise sensor, 21 and 22 are two microphones of the same type that are closely arranged, 23 is a subtraction unit that subtracts the output U21 of the microphone 21 and the output U22 of the microphone 22, and 24 is a subtraction unit 23. Is a determination unit that determines the strength of the wind by receiving the output D2 of. C2 is the determination unit 24
Is a control signal of the wind noise removing unit 25. X2, Y
Reference numerals 2 are an input signal and an output signal to the wind noise removing unit 25, respectively.

The operation of the wind noise sensor constructed as above will be described below. First, with respect to the sound wave, the microphone 21 and the microphone 22 are arranged close to each other, and the output U21 of the microphone 21 and the output U22 of the microphone 22 are subtracted by the subtraction unit 23, so that the output D2 thereof is canceled and disappears. In particular, the canceling effect is great in the low sound range where the wavelength is longer than the distance between the microphones 21 and 22. Further, since the phases of the sound waves coming from the direction perpendicular to the line connecting the microphones 21 and 22 are the same, the output D2 is completely zero. On the other hand, microphone 2
The influence of the wind on 1 and the microphone 22 becomes almost uncorrelated, and the output D2 is usually increased by about 3 dB as compared with the case of one microphone.

As described above, according to the present embodiment, two microphones of the same type are arranged in proximity to each other, and the strength of the wind is determined by using the subtracted value of the outputs of the two microphones, thereby making a response. This makes it possible to detect not only the presence or absence of the wind but also the strength of the wind without causing malfunction even for a sound source with a high speed, low price, and excessive bass range.

In the second embodiment, it is preferable that the directional principal axes of the microphone 21 and the microphone 22 are oriented in the same direction. However, when the directional microphones are used, they need not be oriented in the same direction. There is also an advantage that the vibration noises are canceled by making the main axes in the same direction.

Furthermore, although the second embodiment has been described on the premise that the microphone 21 and the microphone 22 are newly provided, in the case of the microphone array 30 including a plurality of microphones as shown in FIG. It is also possible to share a part. In FIG. 3, reference numeral 31 is a directivity control unit.

FIG. 4 is a block diagram showing the structure of a wind noise sensor according to the third embodiment of the present invention. In FIG. 4, 40 is a wind noise sensor, 41 and 42 are two microphones of the same type that are closely arranged, and 43 is a windscreen provided on the microphone 41 or a wind noise increase / decrease made of a protrusion that generates turbulence. Means, 44 is a judgment unit for judging the strength of the wind by receiving the output U41 of the microphone 41 and the output U42 of the microphone 42. C4 is an output of the determination unit 44 and is a control signal of the wind noise removal unit 45. X
4 and Y4 are an input signal and an output signal to the wind noise removing unit 45, respectively.

The operation of the wind noise sensor constructed as above will be described below. First, since the wind noise increase / decrease unit 43 has almost no effect on sound waves, the same behavior as that of the second embodiment described above is performed. on the other hand,
For wind, the respective outputs U41 and U42 differ depending on the wind noise increasing / decreasing means 43. Therefore, the wind can be detected without being affected by the sound waves.

As described above, according to this embodiment, two microphones of the same type, which are closely arranged, the wind noise increasing / decreasing means provided on one or both of the two microphones, and the two microphones are provided. By including a determination unit that determines the strength of the wind by receiving the output of the microphone, the response speed is fast, the price is low, there is no malfunction even for sound sources with excessive bass range, and the presence or absence of wind The strength can be detected.

Also in the third embodiment, it is preferable that the directivity main axes of the microphone 21 and the microphone 22 are oriented in the same direction for the same reason as in the second embodiment.

Further, in the case of the microphone array as shown in FIG. 3, cost can be reduced by sharing a part of the microphones.

Further, in the third embodiment, the judging section 44 can be constructed by the construction shown in FIG. 5 or 6. In FIG. 5, 51 is a microphone output U41,
A subtraction unit for obtaining the subtraction value of U42, and 52 is an operation unit for receiving the output D5 of the subtraction unit 51 and calculating the wind strength. Further, in FIG. 6, reference numeral 61 designates microphone outputs U41, U
Reference numeral 42 is a level comparison unit for obtaining a relative value, and 62 is a calculation unit for receiving the output D6 of the level comparison unit 61 and calculating the wind strength. By configuring the determination unit 4 in this way, it is possible to effectively determine the wind strength.

[0037]

As described above, according to the present invention, the bidirectional microphone and the determining unit for receiving the output of the bidirectional microphone to determine the strength of the wind are provided or arranged close to each other. Two microphones of the same type and above 2
By including a subtraction unit that subtracts the output of each microphone, and a determination unit that receives the output of the subtraction unit and determines the wind strength, or two microphones of the same type that are arranged close to each other, and By providing the wind noise increasing / decreasing means provided on one or both of the microphones and the determination unit for determining the wind strength by receiving the outputs of the two microphones, the response speed is fast and the price is low. It is possible to provide a wind noise sensor that can detect not only the presence or absence of the wind but also the strength of the wind without malfunction even with a sound source having an excessive low-pitched sound range, and its practical effect is great.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a wind noise sensor according to a first embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a wind noise sensor according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a microphone and a microphone array of the wind noise sensor according to the second embodiment of the present invention.

FIG. 4 is a block diagram showing a configuration of a wind noise sensor according to a third embodiment of the present invention.

FIG. 5 is a block diagram showing a configuration example of a determination unit related to a wind noise sensor according to a third embodiment of the present invention.

FIG. 6 is a block diagram showing another configuration example of the determination unit related to the wind noise sensor according to the third embodiment of the present invention.

FIG. 7 is a block diagram showing the configuration of a wind noise sensor of a second conventional example.

FIG. 8 is a block diagram showing a configuration of a wind noise sensor of a third conventional example.

FIG. 9 is a block diagram showing a configuration of a wind noise sensor of a fourth conventional example.

[Explanation of symbols]

 1 Bidirectional microphone 2, 24, 44 Judgment unit 10, 20, 40 Wind noise sensor 21, 22, 41, 42 Microphone of the same type 23, 51 Subtraction unit 43 Wind noise increase / decrease unit 52, 62 Calculation unit 61 Level comparison unit

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Yuji Yamashina 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (5)

[Claims] 1. A wind noise sensor comprising: a bidirectional microphone; and a determination unit that receives the output of the bidirectional microphone and determines the strength of the wind. 2. A two microphones of the same type arranged in close proximity, a subtraction unit for subtracting the outputs of the two microphones, and a determination unit for receiving the output of the subtraction unit and determining the strength of the wind. A wind noise sensor characterized by being equipped. 3. Two microphones of the same type, which are arranged in close proximity to each other, wind noise increasing / decreasing means provided on one or both of the two microphones, and wind strength received from outputs of the two microphones. A wind noise sensor, comprising: a determination unit for determining. 4. The wind noise sensor according to claim 3, wherein the determination unit determines the strength of the wind by using a subtracted value of the outputs of the two microphones. 5. The wind noise sensor according to claim 3, wherein the determination unit determines the strength of the wind using the relative values of the outputs of the two microphones.