JP7129589B2 - SOUND COLLECTION DEVICE AND IMAGING DEVICE USING THE SAME - Google Patents

Description

The present disclosure relates to a sound collection device that collects sound and an imaging device using the same.

2. Description of the Related Art Conventionally, there is known a sound processing device having an automatic level control (ALC) function for controlling the volume of an input sound to an appropriate level (see, for example, Patent Document 1).

The microphone device of Patent Literature 1 has a mechanical section inside a device housing that generates noise during operation. This microphone device reduces the mixing of internally generated noise when capturing external sounds. The microphone device includes a main microphone, a noise reference microphone, adaptive filter means, signal subtraction means, signal level comparison means, and filter coefficient update control means. The main microphone picks up external sounds coming from outside the device housing. A noise reference microphone is provided inside the instrument housing. The adaptive filter means inputs the detection signal of the noise reference microphone and generates a control sound signal using the updated filter coefficients. A signal subtraction means subtracts the control sound signal of the adaptive filter means from the output signal of the main microphone. A signal level comparison means compares the levels of the output signal of the main microphone and the detection signal of the noise reference microphone. The filter coefficient update control means inputs the comparison result of the signal level comparison means, the subtraction result of the signal subtraction means, and the detection signal of the noise reference microphone. The filter coefficients of the adaptive filter means are updated so that the subtraction result of the subtraction means is minimized.

According to this microphone device, the signal from the noise reference microphone is applied to the adaptive filter means to generate the control sound signal, and the control sound signal cancels the noise. As a result, it is possible to reduce the mixing of internal noise when collecting the external sound.

JP-A-2000-4494

An object of the present disclosure is to reduce noise included in an audio signal when collecting audio from the outside of an electronic device to generate an audio signal, even if the exterior surface has a porous shape.

The present disclosure includes a housing having a porous exterior surface provided with a plurality of holes, a housing disposed inside the housing, and receiving sound pressure from the outside of the housing through the plurality of holes, a primary microphone that produces a first audio signal; a reference microphone that is positioned within the enclosure and proximate to the primary microphone and produces a second audio signal; a first support member provided in the housing for supporting the main microphone; a second support member provided in the interior of the housing for supporting the reference microphone; a first shielding member that shields the interior from the inside; a second shielding member that shields the exterior of the housing from the interior of the reference microphone; and the interior of the housing from the interior of the reference microphone. and a third shielding member that shields.

Further, the present disclosure includes an imaging unit configured to capture an image of a subject and generate an image signal, the sound collection device configured to generate a third audio signal based on the first audio signal and the second audio signal, and the and a control section for recording an image signal on a predetermined recording medium together with the audio signal.

According to the sound collecting device of the present disclosure, even when the external surface of the electronic device is porous, noise included in the sound signal can be reduced when sound from the outside of the electronic device is collected and the sound signal is generated.

FIG. 1 is a diagram showing the configuration of an imaging device of the present disclosure. FIG. 2A is a front view of the imaging device of the present disclosure, showing the position of the punching metal plate. FIG. 2B is a top view of the imaging device of the present disclosure, showing the position of the punching metal plate. FIG. 3 is a perspective view showing the configuration of the main microphone of the present disclosure. FIG. 4 is a diagram schematically showing a cross section of the main microphone along line 4-4 in FIG. FIG. 5 is a diagram illustrating the arrangement of primary and reference microphones of the present disclosure. FIG. 6A is a schematic diagram showing a cross section of the sponge C133 in the imaging device of the present disclosure. FIG. 6B is a schematic diagram showing a cross section of the sponge D134 in the imaging device of the present disclosure. FIG. 7 is a diagram illustrating a configuration relating to a noise suppression function in the digital image/sound processing unit. FIG. 8 shows noise level measurements for various reference microphone arrangements. FIG. 9 is a diagram showing the positions of the main microphone and the reference microphone in the imaging device of the modification. FIG. 10 is a diagram showing a list of first to third shielding members in Embodiment 1 and Modifications.

(Background of invention, etc.)
In Japanese Patent Application No. 2016-243909, the present inventors have found that the camera is suitable for a dust-proof and drip-proof digital camera, and can reduce noise contained in an audio signal when capturing audio from the outside of an electronic device and generating an audio signal. I'm proposing a sound system.

In general, when it is desired to improve the sound quality, it is preferable that the external surface of the electronic device (sound pickup device) has sufficient paths for the sound to reach the main microphone. Therefore, it is desirable that the exterior surface of the electronic device is made of a perforated member, such as a punching metal plate, rather than a member having small holes locally provided at positions facing the main microphone. If the exterior surface is a perforated member such as a punching metal plate, or if the punching metal plate forms an inclined surface rather than a horizontal surface, a reference microphone that captures noise is placed near the main microphone and A microphone is required to cut off sound pressure from the outside of the electronic device. An object of the present disclosure is to reduce noise included in an audio signal when capturing audio from the outside of an electronic device and generating the audio signal, even if the exterior surface has a porous shape.

Hereinafter, embodiments will be described in detail with reference to the drawings as appropriate. However, more detailed description than necessary may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially the same configurations may be omitted. This is to avoid unnecessary verbosity in the following description and to facilitate understanding by those skilled in the art.

It is noted that the inventors provide the accompanying drawings and the following description for a full understanding of the present disclosure by those skilled in the art and are not intended to limit the claimed subject matter thereby. do not have.

(Embodiment 1)
Embodiment 1 will be described below with reference to the drawings.

In Embodiment 1, a digital camera capable of outputting an audio signal is taken as an example of an imaging apparatus. The sound pickup device is built into the digital camera and integrated. As the resolution of digital cameras increases, captured images are more susceptible to camera shake. Therefore, it is desirable to equip a digital camera with a high-performance camera shake correction mechanism, but the drive of the camera shake correction mechanism tends to generate noise. That is, a high-resolution digital camera has a problem that noise is more likely to occur inside the digital camera. Also, in general, when it is desired to improve sound quality, it is desirable that there are many paths for sound to reach the main microphone. In other words, the exterior surface of the digital camera is preferably a perforated exterior surface such as a punching metal plate rather than an exterior surface that locally has small holes as sound paths. However, if the exterior surface is a perforated member such as a punching metal plate, it is practically impossible to hold the main microphone and the reference microphone in the exterior member (casing). In other words, since it is difficult to mold a member having a porous shape by injection molding, it is difficult to integrally mold a recess or the like (supporting member) for fixing the microphone with the housing. In addition, if the punching metal plate has a sloped or curved surface instead of a horizontal surface, it becomes more difficult to mount the microphone so as to hold it in the exterior member (housing).

Therefore, in the first embodiment, even if the main microphone and the reference microphone cannot be mounted in the exterior member, the reference microphone can be arranged near the main microphone, and the sound pressure from the outside can be applied to the reference microphone. To easily realize a blocking configuration.

[1-1. Constitution]
[1-1-1. overall structure]
FIG. 1 is a diagram showing the configuration of a digital camera 100, which is an embodiment of an imaging device equipped with a sound pickup device according to the present disclosure. The digital camera 100 captures an image of a subject, generates image data (still image, moving image), and records it on a recording medium. A digital camera 100 is composed of a camera body 102 and an interchangeable lens 301 attached to the camera body 102 . The digital camera 100 is capable of inputting sound while shooting a moving image, and recording the sound data together with the image data on a recording medium.

[1-1-2. Configuration of Interchangeable Lens]
Interchangeable lens 301 has an optical system including focus lens 310 , correction lens 318 and zoom lens 312 . The interchangeable lens 301 further includes a lens controller 320, a lens mount 330, a focus lens driver 311, a zoom lens driver 313, an aperture 316, an aperture driver 317, an operation ring 315, an OIS (Optical Image Stabilizer) driver 319, a DRAM ( Dynamic Random Access Memory) 321, flash memory 322, and the like.

A lens controller 320 controls the operation of the entire interchangeable lens 301 . The lens controller 320 can control the zoom lens driving section 313 so as to receive the user's operation of the operation ring 315 and drive the zoom lens 312 . The lens controller 320 can control the focus lens driver 311, the OIS driver 319, and the diaphragm driver 317 to drive the focus lens 310, the correction lens 318, and the diaphragm 316, respectively.

The OIS drive unit 319 has a drive mechanism including, for example, a magnet and a flat coil. The OIS driving unit 319 controls the driving mechanism based on the detection signal of the gyro sensor that detects the blurring of the interchangeable lens 301 , and adjusts the correction lens 318 in a plane perpendicular to the optical axis of the optical system according to the blurring of the interchangeable lens 301 . shift the This reduces the influence of camera shake in the captured image.

The lens controller 320 is connected to a DRAM 321 and a flash memory 322, and can write information to and read information from these memories as needed. Lens controller 320 may also communicate with controller 130 via lens mount 330 . Note that the lens controller 320 may be configured by a hardwired electronic circuit, or may be configured by a microcomputer using a program.

The lens mount 330 is connected to the body mount 340 of the camera body 102 to mechanically and electrically connect the interchangeable lens 301 and the camera body 102 . When the interchangeable lens 301 and the camera body 102 are connected, the lens controller 320 and the controller 130 are ready for communication. Body mount 340 can transmit signals received from lens controller 320 via lens mount 330 to controller 130 of camera body 102 .

[1-1-3. Configuration of camera body]
The camera body 102 includes a CCD (Charge Coupled Device) image sensor 143 and an AFE (Analog Front End) 144 . An exterior member (housing) of the camera body 102 includes a case 105 shown in FIG. 2A and punching metal plates 119a, 119b, and 119c shown in FIG. 2B.

A CCD image sensor 143 captures a subject image formed through the interchangeable lens 301 and generates image information. Note that other types of image sensors (for example, complementary metal oxide semiconductor (CMOS) image sensors) may be used as the image sensor.

The AFE 144 performs noise suppression by correlated double sampling on image information read from the CCD image sensor 143, amplifies the input range width of an analog/digital (A/D) converter by an analog gain controller, and performs A/D conversion. A/D conversion is performed by the device.

Camera body 102 further includes audio input section 111 and analog audio processing section 115 . The audio input unit 111 includes two main microphones (main microphone 111R, main microphone 111L) for separately picking up main sounds (sounds to be recorded) from left and right directions. In the first embodiment, an example of the first direction is the left direction, and an example of the second direction is the right direction. The first main microphone is the main microphone 111R, and the second main microphone is the main microphone 111L.

Furthermore, the audio input unit 111 includes a reference microphone 111N that acquires noise information inside the camera body 102 . That is, the reference microphone 111N inputs at least one of noise due to vibration of the camera body 102 and various noises generated inside the camera body 102 . Information acquired by the reference microphone 111N is used to generate a signal (noise component) for suppressing noise contained in the main speech.

Each microphone (primary microphone 111R, primary microphone 111L, and reference microphone 111N) converts an audio signal into an electrical signal (analog audio signal). An analog audio signal from each microphone (primary microphone 111 R, primary microphone 111 L, and reference microphone 111 N) is input to analog audio processing section 115 .

The analog audio processor 115 applies predetermined signal processing to the analog audio signal. The analog audio processing unit 115 converts the processed analog audio signal into a digital audio signal using an A/D converter, and outputs the digital audio signal to the digital image/audio processing unit 120 . Analog audio processing unit 115 is an example of an audio signal processing device. The analog audio processing unit 115 is composed of electronic circuits including analog circuits, and is composed of one or more semiconductor integrated circuits. The analog audio processing unit 115 has an automatic level control (ALC) function. The automatic level control function is a function that automatically adjusts the gain so that the level of the output digital audio signal does not exceed a predetermined upper threshold regardless of the level of the input analog audio signal.

The digital image/sound processing unit 120 performs various types of processing on the image information output from the AFE 144 and the sound signal output from the analog sound processing unit 115 . For example, the digital image/sound processing unit 120 performs gamma correction, white balance correction, flaw correction, encoding processing, and the like on image information according to instructions from the controller 130 . Further, the digital image/sound processing unit 120 performs various processes on the sound signal according to instructions from the controller 130 . The digital image/sound processing unit 120 may be implemented by a hardwired electronic circuit, or may be implemented by a microcomputer that executes a program. The digital image/sound processing unit 120 may be realized as one semiconductor chip integrally with the controller 130 or the like. For example, the digital image/sound processing unit 120 can be configured by a CPU (Central Processing Unit), FPGA (Field-Programmable Gate Array), ASIC (Application Specific Integrated Circuit), or DSP (Digital Signal Processor).

The digital image/sound processing unit 120 performs arithmetic processing on the sound signal output from the sound input unit 111, and performs directivity synthesis processing and noise suppression processing. A circuit that implements the digital image/audio processor 120 may be integrated in one or more semiconductor integrated circuits.

The display unit 190 is arranged on the back surface of the digital camera 100 . The display unit 190 can be composed of a liquid crystal display or an organic EL (Electro Luminescence) display. The display unit 190 displays an image based on the image information processed by the digital image/sound processing unit 120 .

The controller 130 centrally controls the operation of the entire digital camera 100 . The controller 130 may be implemented by a hardwired electronic circuit, or may be implemented by a microcomputer that executes a program. Also, the controller 130 may be realized as one semiconductor chip integrally with the digital image/sound processing unit 120 and the like. Also, the ROM (Read Only Memory) 170 does not need to exist outside the controller 130 (as a separate entity from the controller 130), and may be incorporated inside the controller 130. FIG. For example, the controller 130 can be configured with a CPU, FPGA, ASIC, DSP, or the like.

The ROM 170 stores programs related to automatic focus (AF) control, automatic exposure (AE) control, strobe light emission control, etc., which are to be executed by the controller 130, as well as operations of the entire digital camera 100. Stores programs for general control. ROM 170 stores various conditions and settings for digital camera 100 . In addition, in Embodiment 1, the ROM 170 is a flash ROM.

A RAM (Random Access Memory) 150 functions as a work memory for the digital image/sound processing unit 120 and the controller 130 . The RAM 150 can be realized by SDRAM (Synchronous Dynamic Random Access Memory), flash memory, or the like. The RAM 150 also functions as an internal memory for recording image information, audio signals, and the like.

The external storage medium 160 is a memory device internally provided with a non-volatile storage element such as a flash memory. The external storage medium 160 is detachable from the camera body 102 . The external storage medium 160 records image and audio data processed by the digital image/audio processor 120 under the control of the controller 130 .

The operation unit 180 is a general term for operation interfaces such as operation buttons and operation dials arranged on the exterior of the digital camera 100 . The operation unit 180 accepts user's operations. For example, the operation unit 180 includes a release button, a power switch, a mode dial provided on the top surface of the digital camera 100, a center button and a cross button provided on the back surface of the digital camera 100, a touch panel, and the like. Upon receiving an operation by the user, operation unit 180 notifies controller 130 of signals instructing various operations.

Further, the camera body 102 shifts the CCD 143 according to the blurring of the camera body 102, thereby reducing the influence of camera shake in the captured image. As a configuration for realizing this function, the camera body 102 includes a BIS (Body Image Stabilizer) driving section 181 that moves the CCD 143 based on the shake of the camera body 102 . The BIS drive unit 181 includes, for example, a drive mechanism composed of magnets and flat coils. The BIS driving unit 181 controls the driving mechanism based on signals from the gyro sensor and the position sensor to shift the CCD 143 in a plane perpendicular to the optical axis so as to cancel out the blurring of the camera body 102 .

[1-1-4. Microphone configuration]
Primary microphone 111R, primary microphone 111L, and reference microphone 111N are located inside camera body 102 shown in FIG. 2A. The positions and detailed arrangements of the primary microphone 111R, primary microphone 111L, and reference microphone 111N in the camera body 102 will be described later.

The configuration of the main microphone 111R will be described below. The configuration of the main microphone 111L and the reference microphone 111N is the same as that of the main microphone 111R, so the description thereof will be omitted.

The shape of the main microphone 111R is cylindrical, as shown in FIG. As shown in FIG. 4, the main microphone 111R includes a case 401, a diaphragm 402, a diaphragm ring 403, a spacer 404, a back plate 405, an electrode 406, an insulator 407, and a printed circuit board 408. , and an FET (Field Effect Transistor) 409 .

The case 401 forms part of the exterior of the main microphone 111R. A sound hole 410 is formed on the surface of the case 401 opposite to the printed circuit board 408 . The material of the case 401 is metal. The material of the case 401 is particularly SUS (Steel Use Stainless), aluminum, or the like.

The vibrating membrane 402 has a disk shape. The vibrating membrane 402 is formed by coating the surface of a thin film made of polymer material such as polyethylene terephthalate (PET) with a thickness of several microns to several tens of microns with a metal such as gold or nickel by sputtering or vapor deposition. . The vibrating membrane 402 is arranged inside the case 401 . A vibrating membrane 402 is adhered to a ring-shaped vibrating membrane ring 403 and is taut like a drum membrane. The material of the vibrating membrane ring 403 is metal such as SUS or brass. The vibrating membrane 402 and the vibrating membrane ring 403 are at the same potential as the case 401 due to contact with the case 401 .

The shape of the spacer 404 is ring-shaped. The thickness of the spacer 404 is about several microns to several tens of microns. The material of spacer 404 is an insulating material such as polyimide.

The shape of the back electrode plate 405 is a disc shape. The back electrode plate 405 is a plate obtained by coating a base material made of metal such as SUS or brass with an electret material such as FEP (tetrafluoroethylene-hexafluoropropylene copolymer). An electret material is a polymeric material that retains electric charge semipermanently. Thereby, the back plate 405 retains the charge. The back plate 405 has several holes for air passage. The back plate 405 faces the vibrating membrane 402 via the spacer 404 . That is, the distance between the back plate 405 and the vibrating membrane 402 is approximately the same as the thickness of the spacer 404 .

The shape of the electrode 406 is, for example, a pipe shape, that is, a cylindrical shape. The electrode 406 is arranged between the back plate 405 and the printed circuit board 408 . Electrode 406 electrically connects back plate 405 and printed circuit board 408 .

The shape of insulator 407 is, for example, a pipe shape. An insulator 407 is arranged between the back plate 405 and the electrode 406 and the case 401 . The insulator 407 prevents the back plate 405 and the electrode 406 from conducting with the case 401 .

The printed circuit board 408 forms part of the exterior of the main microphone 111R. The printed circuit board 408 is electrically connected to the back plate 405 via the electrodes 406 . Chip parts such as the FET 409 are surface-mounted on the printed circuit board 408 . A terminal (138 in FIG. 5) is provided on the outside of the printed circuit board 408, that is, on the lower surface on the page of FIG. The electrical output of the main microphone 111R can be taken out from this terminal.

One end of the case 401 is crimped around the lower side of the printed circuit board 408 . That is, one end of the case 401 is sealed so that there is no gap between the printed circuit board 408 and the case 401 . One end of the case 401 electrically connects the case 401 and the printed circuit board 408 .

The operations of the main microphone 111R, the main microphone 111L, and the reference microphone 111N will be described below.

Here, the sound is compressional waves of air and pressure fluctuations of air. When sound passes through sound hole 410 and reaches vibrating membrane 402, vibrating membrane 402 receives pressure. The vibrating film 402 is displaced according to the pressure. That is, the distance d between the diaphragm 402 and the back plate 405 changes. Let the amount of change be Δd. Also, let S be the area of the vibrating film 402 . Furthermore, let Q be the amount of charge held by the back plate 405 . The vibrating membrane 402 and the back plate 405 facing each other form a capacitor. Assuming that the capacitance of the capacitor is C and the dielectric constant is ε, the following formula 1 holds.

Further, if the potential between the vibrating membrane 402 and the back electrode plate 405 is V, the following Equation 2 holds according to Coulomb's law.

From the above formulas 1 and 2, the following formula 3 is established.

The potential change ΔV when the vibration film 402 is displaced by sound and the distance between the vibration film 402 and the back plate 405 changes by Δd is expressed by the following Equation 4.

Equation 4 indicates that the displacement of vibrating membrane 402 due to sound can be extracted as a change in potential.

Note that the capacitance C of the capacitor formed by the vibrating membrane 402 and the back plate 405 is several pF to ten and several pF, and the impedance is high. Therefore, FET 409 mounted on printed circuit board 408 is used to transform this impedance.

[1-1-5. Placement of microphones]
2A and 2B are diagrams showing positions of punching metal plates 119a, 119b, and 119c in the digital camera 100. FIG. The punching metal plates 119a, 119b, and 119c are metal plates formed by pressing a plate-like metal material that has been punched (perforated). Each of the punching metal plates 119a, 119b and 119c is provided with a large number of sound holes 114 of 20 or more. In Embodiment 1, the number of sound holes is around 100 each. Each of these sound holes 114 has a diameter of 0.3 mm or more and 1.0 mm or less. Therefore, the digital camera 100 of Embodiment 1 is more suitable for a digital camera that is not dustproof and splashproof. Note that the punched metal plates 119a, 119b, and 119c may be replaced with metal sheets formed by pressing a sheet-shaped metal material subjected to punching (perforation), or formed metal mesh. The punching metal plates 119a, 119b, and 119c are fitted so as to cover the case 105 made of resin. In Embodiment 1, the punching metal plates 119a, 119b, 119c and the case 105 constitute a housing having a porous exterior surface. The punching metal plates 119a, 119b, and 119c are curved and arranged obliquely with respect to the horizontal direction (horizontal direction on the paper surface of FIG. 2A) during normal photographing.

As shown in FIG. 2B, the main microphone 111R is arranged below the punching metal plate 119a. A main microphone 111L is arranged below the punching metal plate 119b. The area of the punching metal plate 119a is larger than the area of the diaphragm 402 of the main microphone 111R. Therefore, the punching metal plate 119a is arranged not only on the area facing the main microphone 111R but also on its outer periphery. Here, in the case of a dust-proof and drip-proof digital camera, the number of sound holes in the housing is one or more and less than ten for one main microphone, and the sound holes are localized only above the main microphone. is generally placed in On the other hand, the punching metal plate 119a of Embodiment 1 has a large number of sound holes 114 uniformly in the area facing the main microphone 111R and the area around the periphery thereof. Similarly, the punching metal plate 119b has sound holes 114 uniformly in the area facing the main microphone 111L and the area around the periphery thereof. Although the punching metal plate 119c is also arranged above the reference microphone 111N in FIGS. 2A and 2B, the punching metal plate 119c may not be arranged above the reference microphone 111N. That is, the upper portion of the reference microphone 111N may be sealed with the case 105. FIG.

The main microphone 111R, the main microphone 111L, and the reference microphone 111N are arranged inside the camera body 102, that is, inside the case 105, in an area above the camera body 102. FIG. The area where the main microphone 111R is arranged is within the area facing the punching metal plate 119a, and within the area 112R indicated by the dotted line. The area where the main microphone 111L is arranged is within the area facing the punching metal plate 119b and within the area 112L. The region where the reference microphone 111N is arranged is within the region facing the punching metal plate 119c and within the region 112N.

The main microphone 111L and the main microphone 111R are arranged side by side with a predetermined distance (for example, about 15 mm) in the longitudinal direction of the camera body 102 . The longitudinal direction of the camera body 102 is the horizontal direction on the paper surface of FIG. 2A.

The reference microphone 111N is arranged near the main microphone 111R and the main microphone 111L. Also, the reference microphone 111N is arranged at a position such that the distances from the main microphone 111R and the main microphone 111L are equal. As a result, noise suppression processing can be performed on the main audio signals of the left and right channels using one reference microphone 111N. Specifically, the reference microphone 111N is placed at a distance of 5 mm or more and 50 mm or less (for example, 10 mm) from each of the main microphones 111R and 111L.

FIG. 5 is a diagram for explaining the arrangement configuration inside the camera body 102 of the main microphone 111R and the reference microphone 111N. FIG. 5 schematically shows a cross section along line 5-5 in FIG. 2B. Although only the main microphone 111R is shown in FIG. 5, the main microphone 111L is also arranged in the same manner as the main microphone 111R. In the first embodiment, the main microphone 111R and the main microphone 111L are arranged such that the surface having the sound hole 410 faces outward (upward in the plane of FIG. 5) of the case 401 shown in FIG. (downward on the paper surface of FIG. 5). In the reference microphone 111N, the surface of the case 401 having the sound hole 410 faces the inside (the lower side on the page of FIG. 5), and the printed circuit board 408 faces the outside of the camera body 102 (the upper side on the page of FIG. 5). are arranged as follows. The fact that the direction of the reference microphone 111N and the directions of the main microphones 111R and 111L are opposite to each other means that the sound pickup directions of the reference microphone 111N and the main microphones 111R and 111L, that is, the respective vibrating membranes 402 Indicates that the direction in which the sound pressure is received is opposite.

Further, as shown in FIG. 5, a resin case 116 is arranged inside the case 105 . Furthermore, sponge A 131, sponge B 132, sponge C 133, and sponge D 134 are arranged inside the case 105 so as to fill the gaps between the case 105, the resin case 116, the main microphones 111R, 111L, and the reference microphone 111N. .

The main microphone 111R is arranged on a resin case 116 and a sponge A131 provided on the resin case 116. As shown in FIG. A space between the upper surface of the main microphone 111R and the back surface of the case 105 (the surface facing the inside of the digital camera) is filled with a sponge C133. The sponge C133 can pass sound pressure from the outside of the case 105 . The outer peripheral surface of the main microphone 111R (the side surface of the case 401 that is perpendicular to the diaphragm 402) is surrounded by a sponge B132. The sponge B132 is provided with a cylindrical hole so that the cylindrical main microphone 111R can be fitted therein.

A reference microphone 111N is placed in a recess formed by a resin case 116 with a rubber member 113 interposed therebetween.

Here, the shape of the rubber member 113 is a cylindrical shape having end faces. An end face of the rubber member 113 has an opening 113H. However, this opening 113H may not be provided. One end of the rubber member 113 opposite to the end face is open, and the reference microphone 111N is inserted through this open end. In Embodiment 1, the end surface of rubber member 113 is arranged so as to be positioned below the plane of FIG. Therefore, the lower surface of the reference microphone 111N is covered with the end face of the rubber member 113. FIG. Also, the side surface of the reference microphone 111N is covered with the side surface of the rubber member 113 . The reference microphone 111N is press-fitted into the concave portion of the resin case 116 and fixed inside the camera body 102 by elastically deforming the rubber member 113 (especially the rib of the rubber member 113). This makes it difficult for the sound pressure entering from between the resin case 116 and the reference microphone 111N to reach the diaphragm 402 of the reference microphone 111N. Here, as a method of fixing the reference microphone 111N to the resin case 116, instead of the rubber member 113, the rubber member 113 is filled with adhesive or clay to block the sound pressure from entering between the resin case 116 and the reference microphone 111N. You may

Furthermore, the space between the upper surface of the reference microphone 111N and the back surface of the case 105 is filled with a sponge D134. The sponge D134 can block sound pressure from outside the case 105 .

Here, in Embodiment 1, sponge A 131, sponge B 132, sponge C 133, and sponge D 134 were used as filling members for filling the gaps inside case 105. good too. The sponge A 131, sponge B 132, sponge C 133, and sponge D 134 are roughly classified into two types according to the cell structure. One is a sponge having an open cell structure represented by urethane foam as shown in FIG. In other words, the open-cell sponge (an example of the filling member) has many sound pressure transmission paths penetrating from one end to the other end. In Embodiment 1, a sponge having an open cell structure is used as the sponge C133. The other is a general-purpose PE (polyethylene) foam as shown in FIG. 6B or a closed-cell sponge represented by a rubber sponge. Since each cell 118 of the sponge having the closed cell structure is an independent cell 118, there are extremely few transmission paths for sound pressure compared to the sponge having the open cell structure, and virtually no sound passes through. A closed-cell structure is used for sponge A131, sponge B132, and sponge D134. However, Sponge A 131 and Sponge B 132 may use an open cell structure. Further, it is desirable to use a closed cell structure for the sponge D134 as much as possible, but it is also possible to use an open cell structure.

As described above, by arranging the sponges A131 to D134, the resin case 116, and the rubber member 113 with respect to the main microphones 111R and 111L and the reference microphone 111N, in the first embodiment, the resin case 116, the sponge A131, sponge B132, and sponge C133 correspond to the first support member of the present disclosure. Also, the resin case 116, the rubber member 113, and the sponge D134 correspond to the second support member of the present disclosure. Furthermore, the sponge C133 also corresponds to the first filling member of the present disclosure. Furthermore, the sponge A131 and sponge B132 also correspond to the second filling member of the present disclosure.

Furthermore, the transmission path of sound pressure from the outside and inside of the digital camera 100 to the vibrating membranes 402 of the main microphones 111R and 111L will be described below. Sound pressure due to sound (air vibration) from the outside of the digital camera 100 passes through the plurality of sound holes 114 of the punching metal plate 119a, the plurality of bubbles 118 of the sponge C133, and the sound holes 410 of the main microphone 111R. , is transmitted to the diaphragm 402 of the main microphone 111R. Similarly, sound pressure due to sound from the outside of the digital camera 100 passes through the plurality of sound holes 114 of the punching metal plate 119b, the plurality of bubbles 118 of the sponge C133, and the sound holes 410 of the main microphone 111L. It is transmitted to the diaphragm 402 of the microphone 111L.

In the first embodiment, as shown in FIG. 5, the vibration membrane 402 of the main microphone 111R and the internal space located on the center side of the case 105 are the printed circuit board 408 of the main microphone 111R, the sponge A 131, and the sponge B 132. It is cut off with the resin case 116 . Similarly, the inside of the main microphone 111L and the inside of the case 105 positioned at the center side are separated by the resin case 116, the sponge A 131, the sponge B 132, and the printed circuit board 408 of the main microphone 111L. That is, the sound pressure due to the sound inside case 105 is difficult to be transmitted to diaphragm 402 of main microphones 111R and 111L by resin case 116, sponge A131, sponge B132, and printed circuit board 408. FIG.

Next, the sound pressure transmission path from the outside and inside of the digital camera 100 to the diaphragm 402 of the reference microphone 111N will be described. In Embodiment 1, sound pressure from the outside of digital camera 100 passes through sound hole 114 of punching metal plate 119c, and is transmitted through sponge D134, rubber member 113, resin case 116, and printed circuit board 408 of reference microphone 111N. It's getting harder. Note that in the area 112N where the reference microphone 111N is arranged, it is not always necessary to provide the sound hole 114 in the punching metal plate 119c in the case 105. may be shielded by the case 105 .

The inside of the reference microphone 111N and the inside of the case 105 located on the central side are separated by the resin case 116 and the rubber member 113. As shown in FIG.

As described above, in Embodiment 1, as summarized in the list of FIG. It corresponds to the first shielding member. Also, the sponge D134, the rubber member 113, the resin case 116, and the printed circuit board 408 of the reference microphone 111N correspond to the second shielding member of the present disclosure. Furthermore, the resin case 116 and the rubber member 113 correspond to the third shielding member of the present disclosure.

Each terminal 138 of the printed circuit board 408 of the main microphones 111R and 111L and the printed circuit board 408 of the reference microphone 111N is connected to a PCB (Printed Circuit Board) 135 via an FPC (Flexible Printed Circuits) 136 passing through the hole 116H. It is connected.

[1-2. Operation of sound collecting device]
Noise suppression processing for an audio signal in the digital image/audio processing unit 120 of the digital camera 100 will be described. The digital image/sound processing unit 120 executes noise suppression processing based on the signal input from the reference microphone 111N.

The main microphones 111R and 111L receive the main sound from the outside of the digital camera 100 and convert it into an electric signal (hereinafter referred to as "main sound signal") as a first sound signal. The reference microphone 111N receives noise inside the digital camera 100 and converts it into an electrical signal (hereinafter referred to as "noise signal") as a second audio signal.

The analog audio processing unit 115 receives main audio signals from the main microphones 111R and 111L, receives noise signals from the reference microphone 111N, performs predetermined processing, and outputs the signals to the digital image/audio processing unit 120. The digital image and audio processor 120 filters the noise signal to generate a noise component and subtracts the noise component from the main audio signal. As a result, the digital image/audio processor 120 generates an audio signal in which noise is suppressed.

FIG. 7 is a diagram showing a main configuration for implementing noise suppression processing on an audio signal in the digital image/audio processing unit 120. As shown in FIG. For convenience of explanation, FIG. 7 shows a configuration for an audio signal from one of the two left and right main microphones 111R and 111L (main microphone 111L). That is, the digital image/sound processing unit 120 has the configuration shown in FIG. 7 for each channel. The configuration and operation related to noise suppression for an audio signal from the microphone of one channel (main microphone 111L) will be described below, but the same applies to the microphone of the other channel (main microphone 111R).

The digital image/sound processing unit 120 includes an adaptive filter 117a, a coefficient setting unit 117b, and a subtractor 117c.

The coefficient setting unit 117b sets the filter coefficients of the adaptive filter 117a according to noise signals and the like. The adaptive filter 117a filters the output signal (noise signal) from the reference microphone 111N according to the filter coefficient set by the coefficient setting unit 117b, and filters the noise signal included in the audio signal (main audio signal) picked up by the main microphone 111L. generates a noise component that is estimated to be The subtractor 117c subtracts the noise component output from the adaptive filter 117a from the audio signal (main audio signal) picked up by the main microphone 111L. This produces a noise-suppressed speech signal.

In FIG. 7, the transfer function relating to the noise suppression function in the digital image/sound processing unit 120 is defined as follows. Let S(ω, t) be the main speech signal input by the main microphones 111R and 111L, and N(ω, t) be the noise signal input by the reference microphone 111N. The noise signal includes signals due to various noises generated within the camera body 102 . For example, the noise indicated by the noise signal includes the driving sound of the driving mechanism when the BIS driving section 181 drives the CCD 143 .

Let H _SM (ω, t) be the transfer function for the main audio signal S(ω, t) in the main microphones 111R and 111L. Let H _NM (ω, t) be the transfer function for the noise signal N(ω, t) in the main microphones 111R and 111L. Let H _NR (ω, t) be the transfer function for the noise signal N(ω, t) at the reference microphone 111N. When defined in this way, the output signal M(ω, t) of the main microphones 111R and 111L and the output signal R(ω, t) of the reference microphone 111N are given by the following equations (5) and (6), respectively. can get.

M(ω, t)=H _SM (ω, t) S(ω, t)+H _NM (ω, t) N(ω, t) (Formula 5)
_R (ω,t)=HNR(ω,t)N(ω,t) (Equation 6)
Here, it is assumed that the signal component for the main audio signal contained in the output signal R(ω,t) of the reference microphone 111N is negligibly small.

In the output signal M(ω,t) of the main microphones 111R and 111L, the noise component is H _NM (ω,t)·N(ω,t). Therefore, by estimating H _NM (ω, t)·N(ω, t) and subtracting this noise component from the output signal M(ω, t), a noise-suppressed speech signal can be obtained.

Therefore, in the digital image/sound processing unit 120, the coefficient setting unit 117b converts the output signal M(ω,t) of the main microphones 111R and 111L and the output signal R(ω,t) of the reference microphone 111N into The noise component is estimated by comparing them, and the filter coefficient of the adaptive filter 117a is set according to the estimated noise component (H _ENM (ω, t)·N(ω, t)). The adaptive filter 117a generates and outputs a noise component (H _ENM (ω, t)·N(ω, t)) from the output signal R(ω, t). The subtractor 117c subtracts the output signal (H _ENM (ω, t)·N(ω, t)) of the adaptive filter 117a from the output signal M(ω, t). As a result, the noise-suppressed audio signal is output from the analog audio processing unit 115 .

[1-3. Experimental result]
FIG. 8 shows noise level measurements for various reference microphone 111N arrangements. The horizontal axis of FIG. 8 indicates the frequency (Hz) of the audio signal picked up by the sound pickup device, and the vertical axis indicates the level (dB) of the audio signal.

In FIG. 8, the thick curve S indicates the waveform of the audio signal picked up by the main microphones 111R and 111L when the digital image/sound processing unit 120 does not perform the above-described noise suppression processing.

In FIG. 8, the curve indicated by the solid line (Embodiment 1) is output from the sound collecting device in which the main microphone 111R (main microphone 111L) and the reference microphone 111N are arranged as shown in FIG. A waveform of an audio signal is shown.

In FIG. 8, a curve (modification) indicated by a dashed line indicates a waveform of an audio signal output from a sound pickup device in which the main microphone 111R (main microphone 111L) and the reference microphone 111N are arranged as shown in FIG.

In the modification, the following changes are made to the arrangement configuration of the first embodiment of the primary microphone 111R (primary microphone 111L) and the reference microphone 111N shown in FIG. Specifically, first, as shown in FIG. 9, the primary microphone 111R (primary microphone 111L) and the reference microphone 111N are arranged in the same direction. In other words, the main microphone 111R (main microphone 111L) and the reference microphone 111N are arranged so that their printed circuit boards 408 face the inner side of the digital camera 100 (lower side on the page of FIG. 9) than their respective vibrating membranes 402. ing. In the modified example, sponges E131A and F132A are used instead of the rubber member 113 of FIG. 5 to fix the reference microphone 111N between the resin case 116 and the sponge D134. That is, in the modified example, the reference microphone 111N is arranged on the resin case 116 via the sponge E131A, and the bottom surface of the reference microphone 111N is covered with the sponge E131A. The sponge F132A is provided with a cylindrical hole so that the cylindrical reference microphone 111N can be fitted therein. Therefore, the sponge F132A is arranged so as to cover the outer peripheral surface of the reference microphone 111N (the side surface of the case 401 perpendicular to the vibrating membrane 402). The sponge E131A is the same material as the sponge A131. The sponge F132A is the same material as the sponge B132. Additionally, in a modified example, a tape 137 is attached so as to close the sound hole 410 on the top of the reference microphone 111N. In summary, as shown in the list of FIG. 10, in the modified example, similar to the first embodiment, the resin case 116, the sponge A 131, the sponge B 132, and the printed circuit board 408 of the main microphone 111R (main microphone 111L) corresponds to the first shielding member of the present disclosure. Moreover, in the modified example, unlike the first embodiment, the sponge D134 and the tape 137 correspond to the second shielding member of the present disclosure. Also, in the modified example, partly different from the first embodiment, the resin case 116, the sponge E131A, the sponge F132A, and the printed circuit board 408 of the reference microphone 111N correspond to the third shielding member of the present disclosure.

Note that, in the modified example, as in the first embodiment, the sponge A131, the sponge B132, the sponge C133, and the resin case 116 correspond to the first supporting member of the present disclosure. Further, in the modified example, partly different from the first embodiment, the sponge D134, the sponge E131A, the sponge F132A, and the resin case 116 correspond to the second support member of the present disclosure. Furthermore, in the modified example, as in the first embodiment, the sponge C133 corresponds to the first filling member of the present disclosure. Also in the modified example, as in the first embodiment, the sponge A131 and the sponge B132 correspond to the second filling member of the present disclosure.

From the results shown in FIG. 8, it can be seen that the noise suppression effect is higher in the first embodiment and the modified example than when noise processing is not performed. Further, when the first embodiment and the modified example are compared, it can be seen that the noise suppression effect is higher in the first embodiment. With the configuration of the modified example, it is considered that part of the sound pressure input from the outside is transmitted to the vibrating membrane 402 via the sponge D134 and the tape 137, which are the second shielding members. In other words, the second shielding member for blocking the transmission of sound pressure is relatively thicker than a thin member such as an adhesive tape, such as at least one of the resin case 116 and the printed circuit board 408, and transmits sound. It is considered more effective to use a member that combines a member without a path (hole) and the sponge D134.

[1-4. effects, etc.]
A digital camera 100 (an example of an imaging device) according to Embodiment 1 includes a sound pickup device. The sound collecting device includes a case 105 (housing) having an exterior surface in the form of perforations (plurality of sound holes 114) of a punching metal plate 119, and a case 105 disposed inside the case 105, through which the case A main microphone 111R and a main microphone 111L that receive sound pressure from the outside of the case 105 and generate a first audio signal, and a second and a first support member (resin case 116, sponge A 131, sponge B 132, and sponge C 133) provided inside the case 105 and supporting the main microphone 111R and the main microphone 111L. , a second support member (a resin case 116 and a rubber member 113) provided inside the case 105 to support the reference microphone 111N, and a second support member (resin case 116 and rubber member 113) that isolates the inside of the case 105 from the insides of the main microphones 111R and 111L. 1 shielding member (resin case 116, sponge A131, sponge B132, and printed circuit board 408) and a second shielding member (sponge D134, printed circuit board 408, rubber member 113 and resin case 116), and a third shielding member (resin case 116 and rubber member 113) that isolates the inside of the case 105 from the inside of the reference microphone 111N.

In Embodiment 1, by arranging the first shielding member, the second shielding member, and the third shielding member, the external main sound picked up by the digital camera 100 is generated inside the digital camera 100. noise can be efficiently reduced.

Further, in the first embodiment, even if the main microphones 111R, 111L and the reference microphone 111N cannot be mounted in the case 105, the reference microphone 111N can be arranged near the main microphones 111R, 111L and On the other hand, it is possible to easily implement a configuration that blocks the sound pressure from the outside. Therefore, it is possible to suppress the noise generated inside the digital camera 100 from being mixed into the audio signal output from the sound collecting device. For example, in Embodiment 1, resin case 116 and sponges A131 to C133, which are also filling members, are combined as a first support member, and resin case 116 and rubber member 113 are used as a second support member. By using the main microphones 111R and 111L and the reference microphone 111N, the main microphones 111R and 111L and the reference microphone 111N can be easily arranged in the vicinity even when a housing having a porous exterior surface is used. Also, by changing the material of the sponge C133 and the material of the sponges A131, B132 and D134, the sponges A131, B132 and D134 can be used as part of the shielding member.

Further, in Embodiment 1, the perforated metal plates 119a to 119c are used as the casing (a part of the casing) having the porous outer surface, so that the porous shape can be easily formed. Furthermore, since the punching metal plates 119a to 119c are made of metal, they are sturdy and have an electric shielding effect.

Further, in Embodiment 1, the sponges A131, B132, and C133 are used as the first filling member or the second filling member so that even if the back surface of the housing is inclined or curved, the shape of the back surface can be followed. It can be easily molded with a straight die. Also, by combining a plurality of sponges (for example, sponge A131, sponge B132, and sponge C133), the filling member can be easily constructed even if it has a complicated shape. Further, by using porous sponges A 131, B 132, and D 134 having lower rigidity than the resin case 116 and the printed circuit board 408 as a part of the first shielding member or the second shielding member, wind pressure can be absorbed, Mixing of noise can be further suppressed.

Further, in Embodiment 1, the exterior surface (for example, punching metal 119a, punching metal 119b, or punching metal 119c) is a sloped or curved surface. Since Embodiment 1 has the first support member and the second support member, the main microphone and the reference microphone can be easily arranged near each other even if the surface of the exterior is inclined or curved.

In the first embodiment, the first support member and the second support member are separate members that are separable from the parts (punching metals 119a to 119c) having the exterior surface of the housing (case 105). be. Therefore, the main microphones 111R and 111L and the reference microphone 111N can be easily arranged in the vicinity even if the surface of the exterior is inclined or curved.

In the first embodiment, the first support member includes a member (resin case 116) whose shape is fixed, a member (for example, a sponge C133 as a first filling member and a second support member) that is deformable in the compression direction. It is configured by combining a sponge A 131 and a sponge B 132) as filling members. As a result, the main microphones 111R and 111L and the reference microphone 111N can be easily arranged in a desired layout even inside a housing having a porous exterior surface. Furthermore, even if the exterior surface of the case 105 of the digital camera 100 is inclined or curved, the main microphones 111R and 111L and the reference microphone 111N can be easily arranged in a desired layout.

The primary microphones 111R and 111L of Embodiment 1 include a first primary microphone (for example, primary microphone 111R) that inputs sound from a first direction, and a primary microphone that inputs sound from a second direction different from the first direction. and a second primary microphone (eg, primary microphone 111L). As a result, in the first embodiment, it is possible to collect sounds from more directions.

The distance between the reference microphone 111N and the first main microphone (for example the main microphone 111R) in the first embodiment is equal to the distance between the reference microphone 111N and the second main microphone (for example the main microphone 111L). Thus, in Embodiment 1, noise components can be suppressed for audio signals from any of the main microphones 111R and 111L.

Further, in Embodiment 1, as shown in FIG. 5, at least part of the second shielding member is the exterior (printed circuit board 408) of the reference microphone 111N, and at least part of the third shielding member is the resin case. 116. This configuration is effective when the directions of the main microphones 111R and 111L and the reference microphone 111N are to be reversed, or when the rubber member 113 having the opening 113H is to be used.

Further, in Embodiment 1, a first filling member (sponge C133) that fills the space between the front surfaces of the main microphones 111R and 111L and the rear surface of the case 105 and passes sound pressure from the outside of the case 105 is provided. have. As a result, sound pressure from the outside can be transmitted to the vibrating membranes 402 of the main microphones 111R and 111L.

Further, in Embodiment 1, at least a part of the first shielding member is a part of the first supporting member, and is a second filling member (sponge A 131 and Sponge B132). As a result, noise generated inside the digital camera 100 can be blocked, and the main microphones 111R and 111L can be easily arranged inside the digital camera 100. FIG.

The sound collecting apparatus of Embodiment 1 further includes an audio processor that obtains noise components based on the audio signal from the reference microphone 111N and subtracts the noise components from the main audio signals from the main microphones 111R and 111L. . As a result, the noise component can be suppressed by the sound pickup device itself.

(Other embodiments)
As described above, Embodiment 1 has been described as an example of the technology disclosed in the present application. However, the technology in the present disclosure is not limited to this, and can be applied to embodiments in which modifications, replacements, additions, omissions, etc. are made as appropriate. Also, it is possible to combine the constituent elements described in the first embodiment to form a new embodiment.

In Embodiment 1 described above, as shown in FIGS. 2A and 2B, the reference microphone 111N is arranged on the front side (object side) of the camera relative to the main microphones 111R and 111L. may be placed closer to the back side of the camera than the primary microphones 111R and 111L. Also, the main microphone 111R, the main microphone 111L, and the reference microphone 111N are arranged above the digital camera 100 (an example of the electronic device), but the positions of these microphones are not limited to this. For example, the primary microphone 111R, the primary microphone 111L, and the reference microphone 111N may be arranged on at least one of the side and front of the digital camera 100. FIG.

Further, in the above embodiment, the reference microphone 111N is fixed to the concave portion of the resin case 116 via the rubber member 113, but it may be fixed to the resin case 116 by other means. For example, the reference microphone 111N may be directly fixed to the resin case 116 using an adhesive.

In the above embodiment, noise suppression processing for suppressing noise in the main speech signals generated by the main microphones 111R and 111L using the noise signal generated by the reference microphone 111N is described with reference to FIG. However, the noise suppression processing is not limited to this, and various known techniques can be applied.

In Embodiment 1, a punching metal plate, a wire mesh, or the like was given as an example of a housing (a part of the housing) having a porous exterior surface. It may be a member that has

Further, in Embodiment 1, the first support member is composed of the resin case 116, the sponge A131, the sponge B132, and the sponge C133, but this configuration is merely an example. For example, the resin case 116 may be changed to a metallic case. Also, for example, the sponge A 131 and the sponge B 132 may be an integrated sponge or an integrated rubber or the like. Alternatively, the sponge A131 or sponge B132 may be further divided into a plurality of parts. In any case, by combining a member whose shape is fixed like the resin case 116 and a member that is freely deformable in the direction of compression like the sponges A131 to C133, even if the internal space of the housing has a complicated shape. The main microphones 111R and 111L can be easily fixed. However, even when the first support member is composed only of a member with a fixed shape, such as the resin case 116, it is possible to obtain a noise suppression effect by disposing the first shielding member separately.

Further, in Embodiment 1, the second support member is composed of the resin case 116 and the rubber member 113, but this configuration is merely an example. For example, as in the modification of FIG. 9, the resin case 116, the sponge D134, the sponge E131A, and the sponge F132A may be used as the second support members. Further, the sponge E131A and sponge F132A, or the sponge F132A and sponge D134 may each be an integrated sponge or an integrated rubber or the like. Alternatively, sponge D134 to sponge F132A may be further divided into a plurality of parts. In any case, by combining a member whose shape is fixed like the resin case 116 and a member that is freely deformable in the compression direction like sponges D134 to F132A, even if the internal space of the housing has a complicated shape. The reference microphone 111N can be easily fixed.

In the above embodiment, an example in which the sound pickup device of the present disclosure is applied to an interchangeable lens type digital camera is described, but the sound pickup device of the present disclosure is applied to a digital camera in which a lens and a body are integrated. can also

In the above embodiments, the digital camera is assumed to be a digital camera that is not dust-proof and splash-proof. may

In the above embodiment, an example in which the sound collecting device of the present disclosure is applied to a digital camera has been described, but the configuration of the sound collecting device of the present disclosure can also be applied to other electronic devices. For example, the configuration of the sound collecting device of the present disclosure can also be applied to other electronic devices that input sound (video cameras, IC (Integrated Circuit) recorders, etc.). The configuration of the sound collecting device of the present disclosure is particularly useful for electronic equipment that has a noise source inside the electronic equipment.

As described above, the embodiment has been described as an example of the technique of the present disclosure. To that end, the accompanying drawings and detailed description are provided.

Therefore, among the components described in the attached drawings and detailed description, there are not only components essential for solving the problem, but also components not essential for solving the problem in order to illustrate the above technology. can also be included. Therefore, the inclusion of non-essential elements in the accompanying drawings or the detailed description should not be interpreted as essential.

In addition, the above-described embodiments are intended to illustrate the technology of the present disclosure, and various modifications, replacements, additions, omissions, etc. can be made within the scope of the claims or equivalents thereof.

The sound collecting device of the present disclosure can generate a noise-suppressed audio signal by removing the noise component from the input audio signal, and converts the audio into an electric signal and inputs it. An electronic device (video camera, IC recorder, etc.) ), and is particularly useful for electronic devices that have internal noise sources.

100 digital camera (imaging device)
102 camera body 105 case (enclosure)
111 audio input section 111R, 111L main microphone 111N reference microphone 112R, 112L, 112N area 113 rubber member (fixing member)
113H opening 114 sound hole 115 analog sound processing unit 116 resin case 117a adaptive filter 117b coefficient setting unit 117c subtractor 118 bubble 119a, 119b, 119c punching metal plate 120 digital image/sound processing unit 130 controller 131 sponge A
132 Sponge B
131A Sponge E
132A Sponge F
133 Sponge C
134 Sponge D
137 tape 138 terminal 143 CCD image sensor 160 external storage medium 180 operation unit 181 BIS driving unit 301 interchangeable lens 319 OIS driving unit 401 case (exterior)
402 diaphragm 403 diaphragm ring 404 spacer 405 back plate 406 electrode 407 insulator 408 printed circuit board (exterior)
409 FETs
410 tone hole

Claims (2)

a housing having a porous exterior surface provided with a plurality of holes;
a main microphone that is arranged inside the housing, receives sound pressure from outside the housing through the plurality of holes, and generates a first audio signal;
a reference microphone positioned within the interior of the enclosure and proximate to the primary microphone for producing a second audio signal;
a first support member provided inside the housing and supporting the main microphone;
a second support member provided inside the housing and supporting the reference microphone;
a first shielding member that shields the interior of the housing in which the noise source is arranged from the interior of the main microphone;
a second shielding member that shields the exterior of the housing from the interior of the reference microphone;
a third shielding member that shields the interior of the housing in which the noise source is arranged and the interior of the reference microphone;
The first shielding member and the third shielding member do not have a communicating portion that transmits noise from the noise source,
The main microphone and the reference microphone are
a case including a surface in which a sound hole is formed; an opening on the other surface; a diaphragm arranged inside the case; a diaphragm arranged inside the case so as to face the diaphragm; including an electrode plate that forms a capacitor together with the membrane, and a printed circuit board that seals the opening,
the surface of the main microphone on which the sound holes are formed faces the exterior surface, and the surface of the reference microphone on which the sound holes are formed faces the interior of the housing;
At least part of the second shielding member is the printed circuit board of the reference microphone, and at least part of the third shielding member is the second support member. The sound collecting device according to claim 1 , wherein an imaging unit that captures an image of a subject and generates an image signal; and a third audio signal that is generated based on the first audio signal and the second audio signal; and a control unit that records the image signal together with the third audio signal on a predetermined recording medium.

Images