JP2024118157A - Audio capture device - Google Patents

Abstract

To provide a sound acquisition device which can input the vibration sound of a vehicle with high coherence and diffusive noise to a noise microphone in order to enhance the effect of reducing the diffusive noise mixed in an utterance microphone.SOLUTION: An utterance microphone 12 is installed in an OHC 708 that is arranged on a passenger compartment 71 side with respect to a vehicle frame 701 and is fixed to the vehicle frame 701. A noise microphone 20 is installed in the vehicle frame 701 in a manner to be covered by the OHC 708. Since each microphone 12, 20 is installed in this way, it is easy for the noise microphone 20 to acquire the vibration sound 70b of the vehicle 70 and it is possible to install the noise microphone 20 in the vicinity of the utterance microphone 12. Therefore, it is possible to input the vibration sound 70b of the vehicle 70 with high coherence and diffusive noise mixed in the utterance microphone 12 into the noise microphone 20.SELECTED DRAWING: Figure 2

Description

The present invention relates to a voice acquisition device for a voice recognition system.

As an example of this type of voice capture device, the noise reduction circuit described in Patent Document 1 has been known. The noise reduction circuit described in Patent Document 1 uses an adaptive filter to remove noise.

Specifically, the noise reduction circuit of Patent Document 1 includes a voice capture microphone that captures the voice of the speaker inside the vehicle cabin, a noise capture microphone installed inside the vehicle cabin, and a vibration sensor installed outside the vehicle cabin that captures vehicle vibrations that are the source of diffuse noise.

The noise reduction circuit estimates the diffuse noise in the vehicle cabin based on the signal acquired by the noise capture microphone (in other words, the noise microphone) and the signal acquired by the vibration sensor. The noise reduction circuit then reduces noise by subtracting the signal indicating the estimated diffuse noise from the signal acquired by the sound capture microphone (in other words, the speech microphone).

Japanese Patent Application Publication No. 6-83387

When using a voice recognition system in a vehicle interior environment, noise present in the vehicle interior reduces the voice recognition rate. Possible noises in the vehicle interior include, for example, driving noise, wind noise from the air conditioner, and voices emitted by other people (i.e., other people's voices). These noises are input to the speaking microphone along with the voice of the speaker (in other words, the speaker), and are a factor that significantly reduces the voice recognition rate of the voice recognition system.

In response to this, one method for preventing a decrease in voice recognition rate due to noise in the vehicle cabin is acoustic signal processing using a microphone array with multiple microphones. A microphone array system that performs this type of acoustic signal processing performs signal processing on acoustic signals input from multiple microphones, and by reducing only the noise, it outputs the speaker's voice (i.e., the target voice) with emphasis.

In detail, microphone array systems reduce noise by utilizing the time difference in arrival of acoustic signals from multiple channels. Therefore, for highly directional noise (i.e., directional noise) such as the wind noise of an air conditioner or the voices of other people, a noise reduction effect from microphone array systems can be expected. On the other hand, for low-directional noise (i.e., diffuse noise) such as running noise and wind noise caused by the vibration of the entire vehicle, the information required to separate the target voice from the diffuse noise, such as the time difference in arrival of acoustic signals from multiple channels, becomes unclear. Therefore, for diffuse noise, the noise reduction effect from microphone array systems is lower compared to directional noise.

It is therefore conceivable to use the noise reduction circuit of Patent Document 1 to reduce diffuse noise through adaptive filter processing. Here, in order to enhance the effect of reducing diffuse noise through adaptive filter processing, it is necessary to obtain a signal that does not contain the target sound and has high coherence with the diffuse noise mixed into the speech microphone using the noise microphone and use this as the input signal for the adaptive filter. Furthermore, since there are many early reflections, reverberations, and many sound propagation paths within the vehicle cabin, it is necessary to reduce the distance between the speech microphone and the noise microphone in order to increase the above-mentioned coherence.

However, Patent Document 1 does not specify the installation position of each microphone. Therefore, if a speech microphone and a noise microphone are provided as described in Patent Document 1 and the distance between the two microphones is large, the coherence will be low and the effect of reducing diffuse noise will be small. The inventors' detailed study led to the above findings.

In view of the above, the present invention aims to provide a voice acquisition device that can input vehicle vibration noise, which has high coherence with diffuse noise, into a noise microphone in order to enhance the effect of reducing diffuse noise mixed into a speech microphone.

In order to achieve the above object, the voice acquisition device according to claim 1 comprises:
A speech capture device (10) for a speech recognition system, comprising:
a speech microphone (12) for acquiring a voice (73a) of a speaker (72) in a vehicle cabin (71);
The noise microphone (20) is arranged to acquire vibration noise (70b) of a vehicle (70) and is arranged so as to make it difficult to acquire the voice of a speaker and to acquire vibration noise more easily than a speech microphone,
The microphone for speaking is disposed on the vehicle cabin side with respect to a vehicle frame (701) that has a plurality of frame components (702, 702a) and is configured by connecting the plurality of frame components to each other and surrounds the vehicle cabin;
The noise microphone is installed on the nearest frame component (702a), which is the frame component among the multiple frame components that is closest to the speech microphone, or on a part (38, 40) that is fixed to the vehicle cabin side of the nearest frame component.

In this way, the noise microphone can be placed in a position where it is easy for the noise microphone to pick up the vehicle vibration sound and where it is close to the speech microphone. This makes it possible to input the vehicle vibration sound, which has high coherence with the diffuse noise that is mixed into the speech microphone, into the noise microphone.

In addition, in each section of the application documents, each element may be given a reference symbol in parentheses. In this case, the reference symbol merely indicates an example of the correspondence between the element and the specific configuration described in the embodiment described below. Therefore, the present invention is not limited in any way by the description of the reference symbol.

1 is a schematic diagram illustrating a location where a voice capture device is installed in a vehicle and its surroundings in a first embodiment. FIG. 1 is a cross-sectional view showing a schematic configuration of a voice acquisition device according to a first embodiment. FIG. 2 is a block diagram showing an electrical system of the voice acquisition device according to the first embodiment. 4 is a view taken along the arrow IV in FIG. 2, and is a schematic diagram showing an electric board, a speech microphone, and a noise microphone. FIG. 3 is a diagram corresponding to a comparative example to be compared with the first embodiment, in which the sound absorbing material and its surrounding area are extracted from FIG. 2 . FIG. 10 is a diagram showing a sound absorbing material provided in a voice capture device and its surrounding area in a second embodiment, and corresponds to FIG. 5 . FIG. 11 is a cross-sectional view showing a schematic configuration of a voice capture device according to a third embodiment, the cross-sectional view corresponding to FIG. 2 . FIG. 11 is a perspective view showing a schematic view of a sound absorbing material provided in a voice capture device according to a third embodiment. FIG. 11 is a cross-sectional view showing a schematic configuration of a voice capture device according to a fourth embodiment, the cross-sectional view corresponding to FIG. 2 . FIG. 13 is a cross-sectional view showing a schematic configuration of a voice capture device according to a fifth embodiment, the cross-sectional view corresponding to FIG. 2 . 11 is a view taken along the arrow XI direction in FIG. 10 in the fifth embodiment, and is a schematic diagram showing an electric board, a speech microphone, and a noise microphone. FIG. 12 is a cross-sectional view showing the XII-XII section of FIG. 11.

Each embodiment will be described below with reference to the drawings. Note that in the following embodiments, parts that are the same or equivalent to each other are given the same reference numerals in the drawings.

First Embodiment
As shown in FIGS. 1 to 3, the voice acquisition device 10 of the present embodiment is used in a voice recognition system 77 mounted on a vehicle 70. The voice recognition system 77 is a system that acquires a voice 73a of a predetermined speaker 72 and recognizes the voice 73a. The voice recognition system 77 has a voice acquisition device 10 and a voice recognition engine 78. The voice acquisition device 10 acquires the voice 73a of a speaker 72, for example, a driver, seated at a predetermined position in a vehicle interior 71, and outputs a sound signal obtained by reducing noise from the acquired sound to the voice recognition engine 78. Therefore, the voice acquisition device 10 of the present embodiment may be referred to as a noise reduction device that reduces noise from an acquired sound in which the voice 73a of the speaker 72 and noise are mixed.

The voice recognition engine 78 is a type of electronic control device, and is configured as an in-vehicle microcomputer equipped with a CPU, RAM, ROM, non-volatile rewritable memory, etc. (not shown). That is, the voice recognition engine 78 reads and executes a computer program stored in a ROM or non-volatile rewritable memory, which is a non-transient physical recording medium. By executing this computer program, a method corresponding to the computer program is performed. Note that the electric circuit unit 30 described below also has a configuration as such an electronic control device.

The voice recognition engine 78 recognizes the voice information indicated by the voice 73a of the speaker 72 based on the voice signal acquired from the voice acquisition device 10. The voice recognition engine 78 then outputs a control signal corresponding to the recognized voice information to an external in-vehicle device, such as a navigation device or an air conditioning device.

Note that the double-ended arrows in FIG. 1 and FIG. 4, which will be described later, each indicate the orientation of the vehicle 70 on which the voice capture device 10 is mounted. That is, in FIG. 1, the vehicle longitudinal direction D1, which is the front-rear direction of the vehicle 70, and the vehicle vertical direction D2, which is the up-down direction of the vehicle 70, are indicated by double-ended arrows, and in FIG. 4, which will be described later, the vehicle lateral direction D3, which is the left-right direction of the vehicle 70 (in other words, the vehicle width direction D3), is indicated by a double-ended arrow. These directions D1, D2, and D3 intersect with each other, or strictly speaking, are perpendicular to each other.

In the description of this embodiment, the front side in the vehicle longitudinal direction D1 is also referred to as the front side in the vehicle direction, and the rear side in the vehicle longitudinal direction D1 is also referred to as the rear side in the vehicle direction. The upper side in the vehicle vertical direction D2 is also referred to as the upper side in the vehicle direction, and the lower side in the vehicle vertical direction D2 is also referred to as the lower side in the vehicle direction. The left side in the vehicle lateral direction D3 is also referred to as the left side in the vehicle direction, and the right side in the vehicle lateral direction D3 is also referred to as the right side in the vehicle direction.

As shown in Figures 1 and 2, the vehicle 70 of this embodiment is, for example, a passenger car, and includes a vehicle frame 701, an outer panel 705, interior materials 707, and an overhead console 708. The vehicle frame 701 forms the framework of the vehicle 70 and surrounds the passenger compartment 71. The vehicle frame 701 has frame components 702, which are multiple structural members, and is constructed by connecting the multiple frame components 702 to each other. For example, the frame components 702 are connected to each other by welding, bolting, or the like. In the explanation of this embodiment, the overhead console 708 may be abbreviated to OHC 708.

The outer panel 705 forms the outer shell of the vehicle 70, and is made of, for example, metal or resin plate material. The outer panel 705 is disposed on the opposite side of the vehicle frame 701 from the vehicle interior 71 side (i.e., the side opposite the vehicle interior). Therefore, the outer panel 705 faces the vehicle exterior space 70a, which is the space outside the vehicle. The outer panel 705 is disposed with a gap between it and the vehicle frame 701, and is fixed to the vehicle frame 701 by being partially connected to the vehicle frame 701. Methods for fixing the outer panel 705 to the vehicle frame 701 include, for example, welding, bolting, and adhesive bonding.

The interior material 707 is made of, for example, a resin plate material, and is disposed on the passenger compartment 71 side of the vehicle frame 701. Therefore, the interior material 707 faces the passenger compartment 71. In other words, the interior material 707 is disposed so as to separate the vehicle frame 701 from the passenger compartment 71. The interior material 707 is also disposed with a gap between it and the vehicle frame 701, and is fixed to the vehicle frame 701 by being partially connected to the vehicle frame 701. Methods for fixing the interior material 707 to the vehicle frame 701 include, for example, snap fitting, adhesion, screwing, etc.

The OHC708 is an interior product that is installed in the ceiling between the driver's seat and the passenger seat and is mainly responsible for the interior lighting function. Depending on the vehicle model in which it is installed, the OHC708 may also have functions such as a storage compartment, opening and closing the sunroof, an emergency call button, and a hands-free phone switch.
The OHC 708 is made of, for example, resin. The OHC 708 is disposed on the passenger compartment side of the vehicle frame 701, and is fixed to the vehicle frame 701 by screws, snap fitting, or the like. For example, the OHC 708 is located on the upper side of the passenger compartment 71 in the vehicle direction, and is fitted into a hole 707a formed in an interior material 707. The passenger compartment 71 side of the OHC 708 is exposed to the passenger compartment 71.

As shown in Figures 2 to 4, the voice capture device 10 includes multiple speech microphones 12, an electrical board 16, a noise microphone 20, sound absorbing material 24, and an electrical circuit section 30. Note that the OHC 708 and sound absorbing material 24 are omitted from Figure 4.

The speech microphone 12 and the noise microphone 20 each convert the captured sound into an electrical signal and output the electrical signal to the electrical circuit section 30 configured on the electrical board 16. For example, both the speech microphone 12 and the noise microphone 20 are omnidirectional microphones.

The noise microphone 20 is positioned away from the electrical board 16, so the noise microphone 20 is electrically connected to the electrical board 16 via an electric wire 17. The electrical signals output from the microphones 12 and 20, which are analog signals, are converted, for example, into digital signals and then input to the electrical circuit section 30.

Each of the multiple speech microphones 12 is a microphone that captures the voice 73a of a speaker 72 in the vehicle cabin 71 (in other words, the speaker voice 73a). That is, the target sound that the speech microphone 12 captures is the speaker voice 73a. Specifically, in addition to the speaker voice 73a, indoor noise 73b, which is noise within the vehicle cabin 71, is also input to the speech microphone 12, so it can be said that the speech microphone 12 captures primary sound 73 that includes the speaker voice 73a and the indoor noise 73b. The multiple speech microphones 12 as a whole constitute a microphone array.

Indoor noise 73b is composed of diffuse noise and directional noise that is more directional than the diffuse noise. Diffuse noise is noise with low directionality, such as running noise and wind noise that are generated by the vibration of the entire vehicle 70. Directional noise is noise with high directionality, such as the voices of people other than the speaker 72 and the wind noise of the air conditioning system.

Specifically, the vibration noise 70b of the vehicle 70 generated from the vibration 701a of the vehicle frame 701 is the main source of the above-mentioned diffuse noise. In other words, the main component of the diffuse noise contained in the interior noise 73b is the vibration noise 70b of the vehicle 70. The vibration noise 70b of the vehicle 70 penetrates into the passenger compartment 71, for example, from the opposite side of the passenger compartment through the interior material 707.

The electric board 16 is a flat printed circuit board made of a resin plate material as a base material, and multiple circuit patterns are formed on the electric board 16. The electric board 16 is fixed to the OHC 708 by screwing or the like. In other words, the electric board 16 is fixed to the vehicle frame 701 via the OHC 708. Therefore, the electric board 16 is disposed on the passenger compartment 71 side with a gap from the vehicle frame 701. In this embodiment, the OHC 708 functions as a support for the electric board 16 and the components mounted on the electric board 16.

In detail, the electric board 16 is fixed via an OHC 708 to the nearest frame component 702a, which is the frame component closest to the speech microphone 12 among all the frame components 702 of the vehicle frame 701. The electric board 16 is then positioned on the passenger compartment 71 side with a gap between it and the nearest frame component 702a.

The electric board 16 has one surface 161 that is provided on one side of the normal direction Dsb of the electric board 16 (i.e., the board normal direction Dsb) and faces away from the vehicle cabin, and another surface 162 that is provided on the other side of the board normal direction Dsb and faces the vehicle cabin 71. That is, the one surface 161 of the electric board 16 faces the vehicle frame 701. The one surface 161 of the electric board 16 faces the vehicle frame 701 with a gap therebetween. That is, the vehicle frame 701 has a frame facing portion 701b that faces the one surface 161 of the electric board 16 in the board normal direction Dsb as a part of the vehicle frame 701. In this embodiment, the frame facing portion 701b is a part of the nearest frame component 702a.

In other words, the substrate normal direction Dsb is the normal direction of one surface 161 and the normal direction of the other surface 162. Furthermore, one side of the substrate normal direction Dsb may be referred to as the anti-cabin side of the substrate normal direction Dsb, and the other side of the substrate normal direction Dsb may be referred to as the cab 71 side of the substrate normal direction Dsb.

On one surface 161 of the electric board 16, a plurality of speech microphones 12 are arranged side by side at intervals. The plurality of speech microphones 12 are mounted on one surface 161 of the electric board 16. In other words, since the plurality of speech microphones 12 are fixed to the OHC 708 via the electric board 16 as described above, it can be said that the plurality of speech microphones 12 are installed on the OHC 708. Here, "the plurality of speech microphones 12 are installed on the OHC 708" means, in other words, that the plurality of speech microphones 12 are arranged close to the OHC 708 and fixed to the OHC 708.

The multiple speech microphones 12 mounted on the electrical board 16 in this manner are arranged on the vehicle interior 71 side at intervals relative to the vehicle frame 701.

The electric board 16 is also formed with a plurality of audio sound holes 16a penetrating the electric board 16. Each of the plurality of audio sound holes 16a is a hole for guiding the primary sound 73 from inside the vehicle interior 71 to the speech microphone 12. Therefore, the plurality of audio sound holes 16a are provided in one-to-one correspondence with each of the plurality of speech microphones 12. For example, in this embodiment, eight speech microphones 12 are provided, and therefore eight audio sound holes 16a are formed in the electric board 16.

Each of the multiple sound holes 16a has one end 16b provided on one side of the substrate normal direction Dsb and the other end 16c provided on the other side of the substrate normal direction Dsb. Each of the multiple sound holes 16a is arranged so as to overlap the other side of the substrate normal direction Dsb with respect to the speech microphone 12. Therefore, one end 16b of the sound hole 16a opens toward the speech microphone 12, and the other end 16c of the sound hole 16a opens toward the opposite side of the vehicle frame 701 and is open to the vehicle interior 71. Since the sound holes 16a are provided in this manner, the primary sound 73 is transmitted from inside the vehicle interior 71 to each of the multiple speech microphones 12 through the sound holes 16a.

The noise microphone 20 is a microphone that picks up the vibration sound 70b of the vehicle 70. Note that most of the captured noise picked up by the noise microphone 20 is the vibration sound 70b of the vehicle 70, but the noise picked up by the noise microphone 20 also contains some sounds other than the vibration sound 70b of the vehicle 70, such as the speaker's voice 73a.

The noise microphone 20 is disposed on the passenger compartment 71 side of the vehicle frame 701 so as to easily pick up the vibration sound 70b of the vehicle 70, and is fixed to the vehicle frame 701 by screwing, gluing, or the like while in contact with the vehicle frame 701. Since the noise microphone 20 is fixed to the vehicle frame 701 in this way, in other words, the noise microphone 20 is installed on the vehicle frame 701. Here, "the noise microphone 20 is installed on the vehicle frame 701" means, in other words, that the noise microphone 20 is disposed close to the vehicle frame 701 and is fixed to the vehicle frame 701.

In terms of its position relative to the OHC 708, the noise microphone 20 is disposed inside the OHC 708. In other words, the noise microphone 20 is installed on the vehicle frame 701 so as to be covered by the OHC 708.

The distance between the noise microphone 20 and the vehicle frame 701 is shorter than the distance between each of the speech microphones 12 and the vehicle frame 701. In terms of the positional relationship between the noise microphone 20 and the interior material 707, the noise microphone 20 is provided on the opposite side of the interior material 707 from the vehicle cabin (in other words, on the vehicle frame 701 side).

Furthermore, when focusing on the multiple frame components 702, the noise microphone 20 is installed on the closest frame component 702a among all the frame components 702 that the vehicle frame 701 has.

From another perspective, the noise microphone 20 is disposed away from the surface 161 of the electric board 16, between the surface 161 and the frame facing portion 701b of the vehicle frame 701, and is installed on the frame facing portion 701b. In other words, the noise microphone 20 is fixed to the frame facing portion 701b.

The sound-absorbing material 24 significantly attenuates the sound that passes through the sound-absorbing material 24. The sound-absorbing material 24 is made of a material with sound-absorbing properties, such as sponge or urethane foam. The sound-absorbing material 24 is disposed on the passenger compartment 71 side of the vehicle frame 701, and is fixed to the vehicle frame 701 by adhesive or the like.

An internal space 24a is formed inside the sound-absorbing material 24, and the internal space 24a is open only on the vehicle frame 701 side, and all parts other than the opening on the vehicle frame 701 side are covered with the sound-absorbing material 24. The opening on the vehicle frame 701 side of the internal space 24a is blocked by the vehicle frame 701. The noise microphone 20 is disposed in the internal space 24a of the sound-absorbing material 24 and is covered by the sound-absorbing material 24. That is, the noise microphone 20 is disposed in the internal space 24a of the sound-absorbing material 24, which is the space surrounded by the vehicle frame 701 and the sound-absorbing material 24. Therefore, the noise microphone 20 is disposed so that it is less likely to pick up the speaker's voice 73a and more likely to pick up the vibration sound 70b of the vehicle 70 compared to all of the speech microphones 12.

The sound absorbing material 24 has an inner wall surface 24b that faces the internal space 24a of the sound absorbing material 24 and surrounds the internal space 24a. The inner wall surface 24b of the sound absorbing material 24 is formed so as not to include parallel surfaces that are parallel to each other on either side of the internal space 24a. Specifically, the inner wall surface 24b of this embodiment does not include flat portions and has a corrugated uneven structure, so that it is formed so as not to include the above-mentioned parallel surfaces. The unevenness of the inner wall surface 24b prevents standing waves from occurring, and the sound is reflected multiple times and absorbed by the sound absorbing material 24.

The electric circuit section 30 shown in FIG. 3 is composed of one or more electric components such as ICs and resistors mounted on the electric board 16. This electric circuit section 30 performs signal processing to obtain an audio signal in which indoor noise 73b has been reduced from the primary audio 73. From a functional perspective, the electric circuit section 30 has a plurality of first noise reduction sections 31 for obtaining an audio signal in which diffuse noise has been reduced, and a second noise reduction section 32 for obtaining an audio signal in which directional noise has been reduced.

The multiple first noise reduction units 31 are provided in one-to-one correspondence with each of the multiple speech microphones 12. For example, in this embodiment, eight speech microphones 12 are provided, and therefore the electrical circuit unit 30 has eight first noise reduction units 31. One speech microphone 12 and one first noise reduction unit 31 constitute one channel, and therefore eight channels are provided in this embodiment.

Specifically, a primary audio signal S1v indicating a primary audio 73 is input to each of the multiple first noise reduction units 31 from the speech microphone 12 corresponding to that first noise reduction unit 31. In addition, an acquired noise signal Sn indicating acquired noise that is acquired by the noise microphone 20 and includes the vibration sound 70b of the vehicle 70 is input from the noise microphone 20 to each of the multiple first noise reduction units 31.

Then, each of the multiple first noise reduction units 31 obtains a secondary sound signal S2v indicating a secondary sound in which diffuse noise has been reduced compared to the primary sound 73 based on the primary sound signal S1v and the acquired noise signal Sn. This secondary sound signal S2v is output from each of the multiple first noise reduction units 31 to the second noise reduction unit 32. In the secondary sound indicated by the secondary sound signal S2v, diffuse noise is reduced compared to the primary sound 73, so that the secondary sound is a sound in which the speaker's voice 73a is relatively more prominent than the primary sound 73. In other words, the secondary sound indicated by the secondary sound signal S2v is a sound in which the speaker's voice 73a is more prominent than the primary sound 73 due to the diffuse noise being reduced compared to the primary sound 73.

Each of the multiple first noise reduction units 31 has a variable FIR filter 311, an adder 312, and an adaptive algorithm execution unit 313 to obtain a secondary audio signal S2v. The "FIR" in the description of the "variable FIR filter 311" is an abbreviation for "Finite Impulse Response."

The variable FIR filter 311 adjusts the sound pressure and phase in the acquired noise signal Sn and outputs the adjusted sound signal. The adjusted sound signal from the variable FIR filter 311 and the primary sound signal S1v from the speech microphone 12 are input to the adder 312. The adder 312 then inverts the adjusted sound signal from the variable FIR filter 311 and adds the inverted sound signal to the primary sound signal S1v. This added sound signal is the secondary sound signal S2v, and the secondary sound signal S2v is output from the adder 312 to the adaptive algorithm execution unit 313 and the second noise reduction unit 32, respectively.

The adaptive algorithm execution unit 313 processes the secondary audio signal S2v output from the adder 312 using a predetermined adaptive algorithm, and automatically updates the filter coefficients of the variable FIR filter 311. This update of the filter coefficients enables the variable FIR filter 311 to output a sound signal in which the speaker's voice 73a has been effectively removed from the noise acquired by the noise microphone 20. Note that the adaptive algorithm executed by the adaptive algorithm execution unit 313 may be, for example, an LMS algorithm or an RLS algorithm. "LMS" stands for "Least mean square" and "RLS" stands for "Recursive least square".

The second noise reduction unit 32 receives the secondary audio signal S2v from each adder 312 of the multiple first noise reduction units 31. The second noise reduction unit 32 obtains a tertiary audio signal S3v representing a tertiary audio in which directional noise has been reduced compared to the secondary audio, based on the multiple secondary audio signals S2v. This tertiary audio signal S3v is output from the second noise reduction unit 32 to the voice recognition engine 78. The tertiary audio represented by the tertiary audio signal S3v is a sound in which both directional noise and diffuse noise have been reduced compared to the primary audio 73, so that the speaker's voice 73a is relatively more prominent than the secondary audio. In other words, the tertiary audio represented by the tertiary audio signal S3v is a sound in which the speaker's voice 73a is more prominent than the secondary audio due to the directional noise being reduced compared to the secondary audio.

For example, the second noise reduction unit 32 performs microphone array signal processing to reduce directional noise by utilizing the arrival time difference of multiple channel acoustic signals (specifically, multiple secondary audio signals S2v), thereby obtaining a tertiary audio signal S3v. For example, the delay and sum method or blind source separation is used as the microphone array signal processing.

In this way, the tertiary voice signal S3v, in which the noise is reduced and the speaker's voice 73a is emphasized, is input from the electrical circuit section 30 to the voice recognition engine 78, so that the voice recognition engine 78 can increase the voice recognition rate of the speaker's voice 73a.

As described above, according to this embodiment, as shown in FIG. 2, the speech microphone 12 is installed on the OHC 708 that is disposed on the passenger compartment 71 side of the vehicle frame 701 and fixed to the vehicle frame 701. The noise microphone 20 is installed on the vehicle frame 701 so as to be covered by the OHC 708.

In other words, the speech microphone 12 is placed on the vehicle interior 71 side of the vehicle frame 701. The noise microphone 20 is installed on the closest frame component 702a among the multiple frame components 702 that make up the vehicle frame 701.

Furthermore, from another perspective, the speech microphone 12 is mounted on the electric board 16, and the electric board 16 has a surface 161 that faces the frame facing portion 701b, which is part of the nearest frame component 702a. The noise microphone 20 is located away from the surface 161 of the electric board 16, between that surface 161 and the frame facing portion 701b, and is installed on the frame facing portion 701b.

Since the microphones 12, 20 are installed in this manner, the noise microphone 20 can be installed in a position where it is easy for the noise microphone 20 to pick up the vibration sound 70b of the vehicle 70 and where it is close to the speech microphone 12. Furthermore, the noise microphone 20 can be installed in a position close to the speech microphone 12, within the constraint that the noise microphone 20 must be able to pick up the vibration sound 70b of the vehicle 70.

Therefore, it is possible to input the vibration sound 70b of the vehicle 70, which has a high coherence with the diffuse noise mixed into the speech microphone 12, to the noise microphone 20. By using the vibration sound 70b of the vehicle 70 acquired by the noise microphone 20, the amount of reduction in diffuse noise in the first noise reduction unit 31 can be increased. In other words, the effect of reducing the diffuse noise mixed into the speech microphone 12 can be improved.

(1) In addition, according to this embodiment, the sound-absorbing material 24 is disposed on the vehicle interior 71 side with respect to the vehicle frame 701. The sound-absorbing material 24 forms an internal space 24a inside the sound-absorbing material 24, the internal space 24a being open on the vehicle frame 701 side. The noise microphone 20 is disposed in the internal space 24a of the sound-absorbing material 24 and is surrounded by the sound-absorbing material 24.

Therefore, compared to a case where, for example, the sound-absorbing material 24 is not provided, it is possible to prevent the speaker's voice 73a from being mixed into the noise acquired by the noise microphone 20. Furthermore, the amount of diffuse noise reduction in the first noise reduction unit 31 can be increased. As a result, the speaker's voice 73a can be made to stand out in the secondary sound represented by the secondary sound signal S2v output from the first noise reduction unit 31, and ultimately the speech recognition rate of the speaker's voice 73a in the speech recognition engine 78 can be improved.

The noise reduction circuit of Patent Document 1 mentioned above is provided with a vibration sensor in addition to the noise capture microphone. In contrast, in this embodiment, the sound absorbing material 24 prevents the speaker's voice 73a from being mixed into the noise captured by the noise microphone 20, making it possible to eliminate the need for a sensor equivalent to the vibration sensor of Patent Document 1. This makes it possible to reduce the cost of the voice capture device 10, for example.

(2) Furthermore, according to this embodiment, the sound absorbing material 24 has an inner wall surface 24b that faces the internal space 24a of the sound absorbing material 24 and surrounds the internal space 24a. The inner wall surface 24b of the sound absorbing material 24 is formed so as not to include parallel surfaces that are parallel to each other across the internal space 24a.

Now, consider the comparative example in Figure 5. The sound absorbing material 25 in the comparative example in Figure 5 corresponds to the sound absorbing material 24 in the first embodiment. The internal space 25a of the sound absorbing material 25 in the comparative example corresponds to the internal space 24a of the sound absorbing material 24 in the first embodiment, and the inner wall surface 25b of the sound absorbing material 25 in the comparative example corresponds to the inner wall surface 24b of the sound absorbing material 24 in the first embodiment. In the comparative example in Figure 5, the sound absorbing material 25 is different from that in the first embodiment, and everything other than the sound absorbing material 25 is the same as in the first embodiment.

In the comparative example of FIG. 5, the inner wall surface 25b of the sound absorbing material 25 includes parallel surfaces that are parallel to each other across the internal space 25a. For example, the inner wall surface 25b includes parallel surfaces that are parallel to the wall surface of the vehicle frame 701 that faces the internal space 25a. Therefore, sound is repeatedly reflected at the parallel surfaces as shown by arrows A1 and A2, generating standing waves in the sound absorbing material 25. As a result, in the comparative example of FIG. 5, the frequency characteristics of the noise picked up by the noise microphone 20 change, and the noise reduction effect of the first noise reduction unit 31 (see FIG. 3) is reduced.

In contrast, as described above, the inner wall surface 24b of the sound-absorbing material 24 in this embodiment is formed so as not to include parallel surfaces that are parallel to each other across the internal space 24a, so that the sound-absorbing material 24 is less likely to generate standing waves. This prevents the frequency characteristics of the noise picked up by the noise microphone 20 from changing due to the generation of standing waves within the sound-absorbing material 24, and makes it possible to prevent a decrease in the noise reduction effect caused by the generation of standing waves by the sound-absorbing material 24.

(3) Also, according to this embodiment, as shown in Figures 2 and 3, each of the multiple first noise reduction units 31 obtains a secondary sound signal S2v indicating a secondary sound in which diffuse noise has been reduced compared to the primary sound 73, based on the primary sound signal S1v and the acquired noise signal Sn. Then, the second noise reduction unit 32 obtains a tertiary sound signal S3v indicating a tertiary sound in which directional noise has been reduced compared to the secondary sound, based on each of the secondary sound signals S2v obtained by the multiple first noise reduction units 31.

Therefore, the tertiary voice signal S3v input to the voice recognition engine 78 is a signal in which the speaker voice 73a stands out because both directional noise and diffuse noise are reduced compared to the primary voice 73. As a result, the voice recognition rate of the speaker voice 73a in the voice recognition engine 78 can be improved.

In addition, according to this embodiment, as shown in FIG. 2, the noise microphone 20 is disposed on the vehicle interior 71 side relative to the vehicle frame 701, and is disposed on the opposite side of the vehicle interior (in other words, the vehicle frame 701 side) relative to the interior material 707. Therefore, the speaker's voice 73a heading toward the noise microphone 20 is absorbed by the interior material 707, so that the interior material 707 can prevent the speaker's voice 73a from being mixed into the noise acquired by the noise microphone 20. As a result, the amount of noise reduction in the first noise reduction unit 31 is increased.

Second Embodiment
Next, a second embodiment will be described. In this embodiment, differences from the first embodiment will be mainly described. Also, parts that are the same as or equivalent to the above-mentioned embodiment will be omitted or simplified. This also applies to the following embodiments.

As shown in FIG. 6, in this embodiment, as in the first embodiment, the inner wall surface 24b of the sound absorbing material 24 is formed so as not to include parallel surfaces that are parallel to each other across the internal space 24a. However, in this embodiment, the shape of the inner wall surface 24b of the sound absorbing material 24 is different from that in the first embodiment.

Specifically, in a cross section perpendicular to the inner wall surface 24b of the sound-absorbing material 24 (i.e., the cross section in FIG. 6), the inner wall surface 24b is configured by connecting multiple flat sections so that the internal space 24a of the sound-absorbing material 24 has a triangular shape.

Except for what has been described above, this embodiment is similar to the first embodiment. Furthermore, in this embodiment, the same effects as those of the first embodiment can be obtained from the configuration common to the first embodiment described above.

Third Embodiment
Next, a third embodiment will be described, focusing mainly on the differences from the first embodiment.

As shown in Figures 7 and 8, in this embodiment, the shape of the sound-absorbing material 24 is different from that in the first embodiment.

Specifically, the sound absorbing material 24 is formed so as to completely surround the noise microphone 20 when viewed in a direction along the normal direction of the installation surface 701c of the vehicle frame 701 on which the noise microphone 20 is installed (for example, when viewed in the direction indicated by the arrow A3). In this respect, the present embodiment is similar to the first embodiment.

However, in this embodiment, unlike the first embodiment, the sound absorbing material 24 has a shape in which the internal space 24a of the sound absorbing material 24 is open to the side opposite the vehicle frame 701 (i.e., the vehicle interior 71 side). Therefore, when the sound absorbing material 24 of this embodiment is viewed alone, the sound absorbing material 24 has a cylindrical shape, and the internal space 24a of the sound absorbing material 24 is open at both ends of the cylindrical shape.

The electric board 16 is arranged to cover an opening 24c on the vehicle interior 71 side of the internal space 24a of the sound-absorbing material 24 at a distance from the opening 24c. The opening 24c of the sound-absorbing material 24 is located closer to the vehicle frame 701 than the interior material 707.

Therefore, the path of the speaker's voice 73a through the opening 24c of the sound absorbing material 24 to the noise microphone 20 is blocked to some extent by the electric board 16 and the interior material 707. Therefore, in this embodiment as in the first embodiment, the noise microphone 20 is positioned so that it is less likely to pick up the speaker's voice 73a and more likely to pick up the vibration noise 70b of the vehicle 70 compared to all of the speech microphones 12. Note that in this embodiment, since the sound absorbing material 24 is in contact with the OHC 708 on the passenger compartment 71 side, the opening 24c of the sound absorbing material 24 on the passenger compartment 71 side is blocked by the OHC 708.

(1) As described above, according to this embodiment, the sound-absorbing material 24 is formed so as to surround the noise microphone 20 when viewed in a direction along the normal direction of the installation surface 701c of the vehicle frame 701. The sound-absorbing material 24 is shaped so that the internal space 24a of the sound-absorbing material 24 is open to the side opposite the vehicle frame 701 (i.e., the vehicle interior 71 side).

The sound absorbing material 24 therefore gives the noise microphone 20 a directivity towards the speech microphone 12. Therefore, compared to when the interior space 24a on the vehicle interior 71 side is blocked by the sound absorbing material 24, the noise microphone 20 can pick up sounds with higher coherence than the diffuse noise picked up by the speech microphone 12. As a result, the amount of noise reduction in the first noise reduction unit 31 can be increased.

Except for what has been described above, this embodiment is similar to the first embodiment. Furthermore, in this embodiment, the same effects as those of the first embodiment can be obtained from the configuration common to the first embodiment described above.

Note that this embodiment is a modified version of the first embodiment, but it is also possible to combine this embodiment with the second embodiment described above.

Fourth Embodiment
Next, a fourth embodiment will be described. In this embodiment, differences from the first embodiment will be mainly described.

As shown in FIG. 9, the voice capture device 10 of this embodiment includes a vibration-proof material 36, a noise microphone case 37, and a noise microphone board 38. The vibration-proof material 36, the noise microphone case 37, and the noise microphone board 38 are disposed inside the OHC 708 and are covered by the OHC 708. Note that the voice capture device 10 of this embodiment does not include a sound-absorbing material 24 (see FIG. 2).

The vibration-proofing material 36 is made of an elastic material such as rubber or urethane foam, which easily absorbs vibrations. The vibration-proofing material 36 is disposed on the passenger compartment 71 side of the vehicle frame 701 and is fixed to the vehicle frame 701 while in contact with the vehicle frame 701. The vibration-proofing material 36 is formed, for example, in a plate shape that extends along the surface of the vehicle frame 701 with which the vibration-proofing material 36 comes into contact.

The noise microphone case 37 is a housing made of resin or metal, and houses the noise microphone 20 and the noise microphone board 38. The noise microphone case 37 is disposed on the vehicle interior 71 side of the vehicle frame 701. The noise microphone case 37 is fixed to the vehicle frame 701, for example, by screws, with vibration-proof material 36 sandwiched between the noise microphone case 37 and the vehicle frame 701. In other words, the noise microphone case 37 is not in direct contact with the vehicle frame 701, but is fixed to the vehicle frame 701 via the vibration-proof material 36.

The noise microphone case 37 also has multiple case through holes 37a that connect the inside and outside of the noise microphone case 37.

The noise microphone board 38 is a flat printed circuit board made of a resin plate as a base material, and multiple circuit patterns are formed on the noise microphone board 38. Although the electric wire 17 (see FIG. 2) is not shown in FIG. 9, the noise microphone board 38 is electrically connected to the electric board 16 by the electric wire 17.

The noise microphone 20 is mounted on the noise microphone board 38, which is fixed to the noise microphone case 37. Therefore, the noise microphone 20 is fixed to the vehicle frame 701 via the noise microphone board 38, the noise microphone case 37, and the vibration-isolating material 36.

In this embodiment, the noise microphone 20 is also disposed close to the nearest frame component 702a and is fixed to the nearest frame component 702a, so it can be said that the noise microphone 20 is installed on the nearest frame component 702a. Furthermore, since the noise microphone 20 is mounted on the noise microphone board 38, it can also be said that it is installed on the noise microphone board 38, which is a component fixed on the vehicle interior 71 side of the nearest frame component 702a.

The noise microphone board 38 is also formed with a board through hole 38a that penetrates the noise microphone board 38. One end of the board through hole 38a faces the noise microphone 20, and the other end of the board through hole 38a faces the inner wall surface of the noise microphone case 37 in which multiple case through holes 37a are formed.

Therefore, the vibration noise 70b (see FIG. 2) of the vehicle 70 travels from the vehicle frame 701 through the multiple case through-holes 37a and the board through-hole 38a as indicated by arrows B1 and B2, and reaches the noise microphone 20.

In this embodiment, the multiple case through holes 37a are provided on the vehicle interior 71 side of the noise microphone case 37, but the electric board 16 is arranged to cover all of the multiple case through holes 37a at intervals. The multiple case through holes 37a are located closer to the vehicle frame 701 than the interior material 707.

Therefore, the path of the speaker's voice 73a through the case through-hole 37a to the noise microphone 20 is blocked to some extent by the electric board 16 and the interior material 707. Therefore, in this embodiment, as in the first embodiment, the noise microphone 20 is positioned so that it is less likely to pick up the speaker's voice 73a and more likely to pick up the vibration noise 70b of the vehicle 70 compared to all of the speech microphones 12.

(1) As described above, according to this embodiment, the noise microphone 20 is fixed to the vehicle frame 701 via the vibration-isolating material 36. Therefore, the noise microphone 20 can be arranged close to the vehicle frame 701. Furthermore, compared to a case where the noise microphone 20 is, for example, directly attached to the vehicle frame 701, the vibration-isolating material 36 can suppress the noise microphone 20 from vibrating in accordance with the vibration 701a (see FIG. 2) of the vehicle frame 701. Therefore, it is possible to prevent the frequency characteristics of the noise acquired by the noise microphone 20 from changing due to the vibration of the noise microphone 20.

Except for what has been described above, this embodiment is similar to the first embodiment. Furthermore, in this embodiment, the same effects as those of the first embodiment can be obtained from the configuration common to the first embodiment described above.

Fifth Embodiment
Next, a fifth embodiment will be described. In this embodiment, differences from the first embodiment will be mainly described.

As shown in Figs. 10 to 12, in addition to the multiple speech microphones 12, a noise microphone 20 is also mounted on the electric board 16. The voice acquisition device 10 has a microphone support member 40 that includes the electric board 16. In these respects, this embodiment differs from the first embodiment. Note that in this embodiment, the voice acquisition device 10 does not have the sound-absorbing material 24 in Fig. 2, but the inner wall of the case of the noise microphone 20 may have a sound-absorbing material.

Specifically, in this embodiment, a plurality of speech microphones 12 are mounted on one surface 161 of the electric board 16. In addition, a noise microphone 20 is also mounted on one surface 161 of the electric board 16. For example, the noise microphone 20 is disposed apart from each of the plurality of speech microphones 12 on one surface 161 of the electric board 16. In this embodiment, since the noise microphone 20 is mounted on the electric board 16, the electric wire 17 shown in FIG. 2 is not necessary.

The microphone support member 40 has an electric board 16, a first laminate plate 41, and a second laminate plate 42. The first laminate plate 41 and the second laminate plate 42 are, for example, resin plates, and are formed in the shape of flat plates having a thickness in the same direction as the thickness direction of the electric board 16. The electric board 16, the first laminate plate 41, and the second laminate plate 42 are fixed to each other, for example, by gluing or screwing, so as to be integrally configured.

The microphone support member 40 is fixed to the OHC 708 by screwing or the like. That is, the microphone support member 40 is fixed to the vehicle frame 701 via the OHC 708. Therefore, the microphone support member 40 is disposed on the passenger compartment 71 side with a gap from the vehicle frame 701. This microphone support member 40 is configured as a microphone board for supporting each microphone 12, 20 on the vehicle frame 701.

In this embodiment, the noise microphone 20 is also disposed close to the nearest frame component 702a and fixed to the nearest frame component 702a, so it can be said that the noise microphone 20 is installed on the nearest frame component 702a. Furthermore, since the noise microphone 20 is mounted on the electric board 16, it can also be said that it is installed on the electric board 16, which is a component fixed on the vehicle interior 71 side of the nearest frame component 702a. And, as described above, the microphone support member 40 has the electric board 16, so it can also be said that the noise microphone 20 is installed on the microphone support member 40, which is a component fixed on the vehicle interior 71 side of the nearest frame component 702a.

The first laminate 41 is laminated on the other side 162 of the electric board 16, for example in close contact with the other side 162 of the electric board 16. The second laminate 42 is laminated on the other side 162 of the electric board 16 with the first laminate 41 sandwiched therebetween, for example in close contact with the first laminate 41.

The microphone support member 40 is also formed with a plurality of voice sound holes 40a and noise sound holes 40e. This allows the microphone support member 40 to function as an acoustic tube. That is, the microphone support member 40 as an acoustic tube guides the speaker's voice 73a from inside the vehicle compartment 71 to the plurality of speech microphones 12 through the respective voice sound holes 40a. At the same time, the microphone support member 40 guides the vibration sound 70b of the vehicle 70 from the vehicle frame 701 side to the noise microphone 20 through the noise sound holes 40e.

Each of the multiple sound holes 40a for audio in the microphone support member 40 is formed as a through hole that penetrates the microphone support member 40 in the substrate normal direction Dsb. That is, the sound holes 40a for audio penetrate the electric substrate 16, the first laminate plate 41, and the second laminate plate 42 in a straight line. The sound holes 40a for audio in this embodiment include the sound holes 16a for audio in the first embodiment (see FIG. 2).

Each of the multiple audio sound holes 40a is a hole for guiding the primary sound 73 from inside the vehicle interior 71 to the speech microphone 12. Therefore, the multiple audio sound holes 40a are provided in one-to-one correspondence with each of the multiple speech microphones 12. For example, in this embodiment, eight speech microphones 12 are provided, so eight audio sound holes 40a are formed in the microphone support member 40.

Each of the multiple sound holes 40a has one end 40b provided on one side of the substrate normal direction Dsb and the other end 40c provided on the other side of the substrate normal direction Dsb. Each of the multiple sound holes 40a is arranged so as to overlap the other side of the substrate normal direction Dsb with respect to the speech microphone 12. Therefore, one end 40b of the sound hole 40a opens toward the speech microphone 12, and the other end 40c of the sound hole 40a opens toward the opposite side of the vehicle frame 701 and is open to the vehicle interior 71. Since the sound holes 40a are provided in this manner, the primary sound 73 is transmitted from inside the vehicle interior 71 to each of the multiple speech microphones 12 through the sound holes 40a.

The noise sound hole 40e of the microphone support member 40 is a hole for guiding the vibration sound 70b of the vehicle 70 from the vehicle frame 701 side of the electric board 16 to the noise microphone 20. This noise sound hole 40e is formed by bending in the microphone support member 40. The noise sound hole 40e has one end 40f and the other end 40g formed on one surface 161 of the electric board 16. One end 40f of this noise sound hole 40e opens toward the noise microphone 20, and the other end 40g of the noise sound hole 40e opens toward the vehicle frame 701 side. In detail, the other end 40g of the noise sound hole 40e is not blocked and is open toward the vehicle frame 701 side. Since the noise sound hole 40e is provided in this way, the vibration sound 70b of the vehicle 70 is transmitted, for example, from the vehicle frame 701 to the noise microphone 20 through the noise sound hole 40e.

Specifically, the noise sound hole 40e is composed of a first board through hole 40h including one end 40f of the noise sound hole 40e, a second board through hole 40i including the other end 40g of the noise sound hole 40e, and a connecting hole 40j. The first board through hole 40h penetrates the electric board 16 at a position facing the noise microphone 20 on one surface 161 of the electric board 16. The second board through hole 40i penetrates the electric board 16 at a position away from both the multiple speech microphones 12 and the noise microphone 20. The connecting hole 40j penetrates the first laminated plate 41 and connects the first board through hole 40h and the second board through hole 40i. Furthermore, the connecting hole 40j on the passenger compartment 71 side (i.e., the opposite side to the vehicle frame 701 side) is blocked by the second laminated plate 42.

By configuring the microphone support member 40 in this manner, in the same way as in the first embodiment, in this embodiment, the noise microphone 20 is positioned so that it is less likely to pick up the speaker's voice 73a and more likely to pick up the vibration noise 70b of the vehicle 70 compared to all of the speech microphones 12.

(1) As described above, according to this embodiment, the microphone support member 40 includes an electric board 16 on which the speech microphone 12 and the noise microphone 20 are mounted. One end 40b of the voice sound hole 40a opens toward the speech microphone 12, and the other end 40c of the voice sound hole 40a opens toward the side opposite the vehicle frame 701. On the other hand, one end 40f of the noise sound hole 40e opens toward the noise microphone 20, and the other end 40g of the noise sound hole 40e opens toward the vehicle frame 701.

Therefore, the noise microphone 20 and the speech microphone 12 can be arranged on one electric board 16 so that the noise microphone 20 is less likely to pick up the speaker's voice 73a and is more likely to pick up the vibration noise 70b of the vehicle 70 compared to all of the speech microphones 12. By having the noise microphone 20 and the speech microphone 12 on a common electric board 16 in this way, it is possible to form a short signal transmission path between each microphone 12, 20 and the electric circuit section 30 configured on the electric board 16.

In other words, if the output signal of the noise microphone 20 is an analog signal, degradation of the signal quality can be prevented. Also, if the output signal of the noise microphone 20 is a digital signal, deterioration of EMC performance can be prevented. "EMC" is an abbreviation for "Electromagnetic Compatibility."

In addition, by mounting all microphones 12, 20 on a common electrical board 16, it is possible to reduce the amount of installation work required to install the voice capture device 10 on the vehicle 70.

(2) According to this embodiment, the noise microphone 20 is mounted on one surface 161 of the electric board 16 together with the multiple speech microphones 12. The noise sound hole 40e of the microphone support member 40 is composed of a first board through hole 40h, a second board through hole 40i, and a connecting hole 40j. The first board through hole 40h penetrates the electric board 16 at a position on the one surface 161 of the electric board 16 facing the noise microphone 20, and the second board through hole 40i penetrates the electric board 16 at a position away from all the microphones 12, 20. The connecting hole 40j penetrates the first laminated plate 41 and connects the first board through hole 40h and the second board through hole 40i, and the side of the connecting hole 40j opposite the vehicle frame 701 side is blocked by the second laminated plate 42.

With this configuration, the microphones 12, 20 are positioned so that the noise microphone 20 is less likely to pick up the speaker's voice 73a and more likely to pick up the vibration noise 70b of the vehicle 70 compared to all of the speech microphones 12. While realizing this arrangement of the microphones 12, 20, all of the microphones 12, 20 can be mounted on one side of the electric board 16. This makes it possible to reduce the mounting costs of mounting the microphones 12, 20 on the electric board 16, compared to when, for example, multiple microphones 12, 20 are mounted separately on one side 161 and the other side 162 of the electric board 16.

Except for what has been described above, this embodiment is similar to the first embodiment. Furthermore, in this embodiment, the same effects as those of the first embodiment can be obtained from the configuration common to the first embodiment described above.

This embodiment is a modification based on the first embodiment, but it is also possible to combine this embodiment with the fourth embodiment described above. In a modification combining the fourth embodiment with this embodiment, for example, the OHC 708 is fixed to the vehicle frame 701 with the vibration-proof material 36 (see FIG. 9) sandwiched between the OHC 708 and the vehicle frame 701.

Other Embodiments
(1) In the above-described embodiments, both the speech microphone 12 and the noise microphone 20 shown in Fig. 2 and the like are omnidirectional microphones, but this is just one example. For example, the speech microphone 12 may be a directional microphone, and the noise microphone 20 may also be a directional microphone.

For example, in the fifth embodiment, the speech microphone 12 shown in Figures 10 and 12 may have a directivity with the highest sensitivity toward one end 40b of the sound hole 40a for voice. And in the fifth embodiment, the noise microphone 20 may have a directivity with the highest sensitivity toward one end 40f of the noise sound hole 40e.

(2) In each of the above-described embodiments, as shown in Figs. 2 and 4, eight speech microphones 12 are provided, but there is no limit to the number of speech microphones 12 as long as there are multiple microphones. Furthermore, if there is no need to reduce directional noise, one speech microphone 12 may be sufficient.

(3) In each of the above-described embodiments, as shown in FIG. 3, the voice acquisition device 10 includes an electric circuit unit 30, but this is only one example. For example, the voice acquisition device 10 may not include the electric circuit unit 30, and an electronic control device equivalent to the electric circuit unit 30 may be provided separately from the voice acquisition device 10.

(4) In each of the above-described embodiments, the speech microphone 12 is attached to the OHC 708, as shown in FIG. 2, but this is just one example. As long as the speaker's voice 73a is input to the speech microphone 12 satisfactorily, the speech microphone 12 may be attached to a location other than the OHC 708, such as the instrument panel, headliner, center console, center cluster, or roof panel.

(5) The present invention is not limited to the above-described embodiments, but can be implemented in various modified forms. Furthermore, the above-described embodiments are not unrelated to each other, and can be combined as appropriate, except in cases where the combination is clearly impossible.

In addition, in each of the above embodiments, it goes without saying that the elements constituting the embodiment are not necessarily essential, except when it is specifically stated that they are essential or when it is clearly considered essential in principle. In addition, in each of the above embodiments, when the numbers, values, amounts, ranges, etc. of the components of the embodiment are mentioned, they are not limited to the specific numbers, except when it is specifically stated that they are essential or when it is clearly limited to a specific number in principle. In addition, in each of the above embodiments, when the material, shape, positional relationship, etc. of the components are mentioned, they are not limited to the material, shape, positional relationship, etc., except when it is specifically stated that they are essential or when it is clearly limited to a specific material, shape, positional relationship, etc. in principle.

(Features of the present invention)
[Claim 1]
A speech capture device (10) for a speech recognition system, comprising:
a speech microphone (12) for acquiring a voice (73a) of a speaker (72) in a vehicle cabin (71);
a noise microphone (20) for acquiring vibration noise (70b) of a vehicle (70), the noise microphone (20) being disposed so as to make it more difficult to acquire the voice of the speaker and to make it easier to acquire the vibration noise as compared with the speech microphone;
the speech microphone has a plurality of frame components (702, 702a) which are connected to each other, and is disposed on the vehicle cabin side with respect to a vehicle frame (701) surrounding the vehicle cabin;
The noise microphone is installed in a nearest frame component (702a), which is the frame component among the multiple frame components that is closest to the speech microphone, or in a part (38, 40) that is fixed to the vehicle cabin side of the nearest frame component, in a voice acquisition device.
[Claim 2]
The speech microphone is installed on a support (708) that is disposed on the vehicle cabin side with respect to the vehicle frame and is fixed to the vehicle frame;
The voice capturing device according to claim 1 , wherein the noise microphone is mounted on the vehicle frame so as to be covered by the support body.
[Claim 3]
3. The voice acquisition device according to claim 1, wherein the noise microphone is fixed to the vehicle frame via a vibration isolator (36).
[Claim 4]
a sound absorbing material (24) disposed on the vehicle cabin side relative to the vehicle frame;
The sound absorbing material forms an internal space (24a) inside the sound absorbing material, the internal space (24a) being open on the vehicle frame side,
4. The voice capture device according to claim 1, wherein the noise microphone is disposed in the interior space and surrounded by the sound absorbing material.
[Claim 5]
The voice acquisition device according to claim 4 , wherein an inner wall surface (24 b) that faces the internal space of the sound-absorbing material and surrounds the internal space is formed so as not to include parallel surfaces that are parallel to each other across the internal space.
[Claim 6]
the sound absorbing material is formed so as to surround the noise microphone when viewed in a direction along a normal direction of an installation surface (701c) of the vehicle frame on which the noise microphone is installed,
The sound acquisition device according to claim 4 , wherein the sound absorbing material has an internal space that opens to a side opposite to the vehicle frame side.
[Claim 7]
an electric board (16) on which the speech microphone is mounted, which is disposed on the vehicle interior side with a gap between the electric board and the nearest frame component and fixed to the nearest frame component;
The electric board has one surface (161) facing a frame facing portion (701b) which is a part of the nearest frame component,
The voice acquisition device according to claim 1 , wherein the noise microphone is disposed away from the one surface of the electric board between the one surface and the frame facing portion and is installed on the frame facing portion.
[Claim 8]
a microphone support member (40) including an electric board (16) on which the speech microphone and the noise microphone are mounted, the microphone support member (40) being disposed on the vehicle cabin side with respect to the vehicle frame and fixed to the vehicle frame;
The microphone support member is formed with a sound hole (40a) for voice and a sound hole (40e) for noise,
One end (40b) of the sound hole for voice opens toward the microphone for speaking,
The other end (40c) of the sound hole for sound opens toward the opposite side to the vehicle frame side,
One end of the noise sound hole (40f) opens toward the noise microphone,
The voice capture device according to claim 1 or 2, wherein the other end (40g) of the noise sound hole opens toward the vehicle frame.
[Claim 9]
the microphone support member (40) includes an electric board (16) on which the speech microphone and the noise microphone are mounted and which has one surface (161) facing the vehicle frame and another surface (162) opposite to the one surface, a first laminate plate (41) laminated on the other surface side of the electric board, and a second laminate plate (42) laminated on the other surface side of the electric board with the first laminate plate sandwiched therebetween, the microphone support member (40) being disposed on the passenger compartment side of the vehicle frame and fixed to the vehicle frame,
The microphone support member is formed with a sound hole (40a) for voice and a sound hole (40e) for noise,
The sound hole for voice is formed as a through hole penetrating the microphone support member in a normal direction (Dsb) of the one surface,
One end (40b) of the sound hole for voice opens toward the microphone for speaking,
The other end (40c) of the sound hole for sound opens toward the opposite side to the vehicle frame side,
the noise sound hole is composed of a first board through hole (40h) that penetrates the electric board at a position facing the noise microphone on the one surface, a second board through hole (40i) that penetrates the electric board at a position away from the speech microphone and the noise microphone, and a connecting hole (40j) that penetrates the first laminate and connects the first board through hole and the second board through hole,
The voice acquisition device according to claim 1 , wherein the connecting hole is closed at a side opposite to the vehicle frame by the second laminate plate.
[Claim 10]
A plurality of first noise reduction units (31);
A second noise reduction unit (32),
A plurality of microphones for speech are provided, and a primary sound (73) including the voice of the speaker is acquired;
the first noise reduction units are provided corresponding to the plurality of speech microphones, respectively, and obtain a secondary sound signal (S2v) indicative of a secondary sound in which the voice of the speaker is accentuated by reducing diffuse noise compared to the primary sound, based on a primary sound signal (S1v) indicative of the primary sound obtained from the speech microphone and an acquired noise signal (Sn) indicative of noise including the vibration sound obtained by the noise microphone;
The voice acquisition device described in any one of claims 1 to 9, wherein the second noise reduction unit obtains a tertiary voice signal (S3v) indicating a tertiary voice in which the voice of the speaker is highlighted by reducing directional noise, which is more directional than the diffuse noise, compared to the secondary voice, based on each of the secondary voice signals obtained by the multiple first noise reduction units.

10 Voice acquisition device 12 Speech microphone 20 Noise microphone 70 Vehicle 70b Vibration sound 72 Speaker 71 Vehicle interior 73a Speaker voice (speaker's voice)
701 Vehicle frame 708 OHC (support)

Claims (10)

A speech capture device (10) for a speech recognition system, comprising:
a speech microphone (12) for acquiring a voice (73a) of a speaker (72) in a vehicle cabin (71);
a noise microphone (20) for acquiring vibration noise (70b) of a vehicle (70), the noise microphone (20) being disposed so as to make it difficult to acquire the voice of the speaker and to make it easier to acquire the vibration noise as compared with the speech microphone;
the speech microphone has a plurality of frame components (702, 702a) which are connected to each other, and is disposed on the vehicle cabin side with respect to a vehicle frame (701) which surrounds the vehicle cabin;
The noise microphone is installed in a nearest frame component (702a), which is the frame component among the multiple frame components that is closest to the speech microphone, or in a part (38, 40) fixed to the vehicle cabin side of the nearest frame component, in a voice acquisition device. The speech microphone is installed on a support (708) that is disposed on the vehicle cabin side with respect to the vehicle frame and is fixed to the vehicle frame;
The voice capturing device according to claim 1 , wherein the noise microphone is mounted on the vehicle frame so as to be covered by the support body. The voice acquisition device according to claim 1, wherein the noise microphone is fixed to the vehicle frame via a vibration-isolating material (36). a sound absorbing material (24) disposed on the vehicle cabin side relative to the vehicle frame;
The sound absorbing material forms an internal space (24a) inside the sound absorbing material, the internal space (24a) being open on the vehicle frame side,
The sound capturing device of claim 1 , wherein the noise microphone is disposed in the interior space and surrounded by the sound absorbing material. The voice acquisition device according to claim 4, wherein the inner wall surface (24b) that faces the internal space of the sound absorbing material and surrounds the internal space is formed so as not to include parallel surfaces that are parallel to each other across the internal space. the sound absorbing material is formed so as to surround the noise microphone when viewed in a direction along a normal direction of an installation surface (701c) of the vehicle frame on which the noise microphone is installed,
The sound acquisition device according to claim 4 , wherein the sound absorbing material has an internal space that opens to a side opposite to the vehicle frame side. an electric board (16) on which the speech microphone is mounted, which is disposed on the vehicle interior side with a gap between the electric board and the nearest frame component and fixed to the nearest frame component;
The electric board has one surface (161) facing a frame facing portion (701b) which is a part of the nearest frame component,
The voice acquisition device according to claim 1 , wherein the noise microphone is disposed apart from the one surface of the electric board between the one surface and the frame facing portion, and is installed on the frame facing portion. a microphone support member (40) including an electric board (16) on which the speech microphone and the noise microphone are mounted, the microphone support member (40) being disposed on the vehicle cabin side with respect to the vehicle frame and fixed to the vehicle frame;
The microphone support member is formed with a sound hole (40a) for voice and a sound hole (40e) for noise,
One end (40b) of the sound hole for voice opens toward the microphone for speaking,
The other end (40c) of the sound hole for sound opens toward the opposite side to the vehicle frame side,
One end of the noise sound hole (40f) opens toward the noise microphone,
The voice capturing device according to claim 1 , wherein the other end (40 g) of the noise sound hole opens toward the vehicle frame. the microphone support member (40) includes an electric board (16) on which the speech microphone and the noise microphone are mounted and which has one surface (161) facing the vehicle frame and another surface (162) opposite to the one surface, a first laminate plate (41) laminated on the other surface side of the electric board, and a second laminate plate (42) laminated on the other surface side of the electric board with the first laminate plate sandwiched therebetween, the microphone support member (40) being disposed on the passenger compartment side of the vehicle frame and fixed to the vehicle frame,
The microphone support member is formed with a sound hole (40a) for voice and a sound hole (40e) for noise,
The sound hole for voice is formed as a through hole penetrating the microphone support member in a normal direction (Dsb) of the one surface,
One end (40b) of the sound hole for voice opens toward the microphone for speaking,
The other end (40c) of the sound hole for sound opens toward the opposite side to the vehicle frame side,
the noise sound hole is composed of a first board through hole (40h) that penetrates the electric board at a position facing the noise microphone on the one surface, a second board through hole (40i) that penetrates the electric board at a position away from the speech microphone and the noise microphone, and a connecting hole (40j) that penetrates the first laminate and connects the first board through hole and the second board through hole,
The voice acquisition device according to claim 1 , wherein the connecting hole is closed at a side opposite to the vehicle frame by the second laminate plate. A plurality of first noise reduction units (31);
A second noise reduction unit (32),
A plurality of microphones for speech are provided, and a primary sound (73) including the voice of the speaker is acquired;
the first noise reduction units are provided corresponding to the plurality of speech microphones, respectively, and obtain a secondary sound signal (S2v) indicative of a secondary sound in which the voice of the speaker is accentuated by reducing diffuse noise compared to the primary sound, based on a primary sound signal (S1v) indicative of the primary sound obtained from the speech microphone and an acquired noise signal (Sn) indicative of noise including the vibration sound obtained by the noise microphone;
The voice acquisition device described in any one of claims 1 to 9, wherein the second noise reduction unit obtains a tertiary voice signal (S3v) indicating a tertiary voice in which the voice of the speaker is highlighted by reducing directional noise, which is more directional than the diffuse noise, compared to the secondary voice, based on each of the secondary voice signals obtained by the multiple first noise reduction units.

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