JP2011114465A - Voice processing apparatus and electronic camera - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a voice processing apparatus for improving the accuracy for reducing noise included in a desired voice signal. <P>SOLUTION: The voice processing apparatus (11) includes: a first microphone (111) in which a sound collecting direction is turned to the outside of a device for performing recording; and a noise processing part (120) for outputting a signal obtained by excluding a noise signal from a voice signal on the basis of the voice signals output from a second microphone (112) provided near the first microphone (111), wherein a sound collecting direction is turned to the inside of the device, and from the first microphone (111), and the noise signal output from the second microphone (112) and showing operation sound that occurs inside the device. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a sound processing device for removing noise and an electronic camera including the sound processing device.

  Conventionally, electronic cameras have been aimed at capturing still images, and moving image shooting has been an additional function. In recent years, high-performance imaging devices and signal processing circuits included in electronic cameras have made it possible to shoot moving images even with single-lens reflex type electronic cameras. However, single-lens reflex electronic cameras generate operating noise (noise) due to the drive mechanism used for the zoom function, autofocus function, camera shake correction function, etc. of the interchangeable lens (lens barrel), and when shooting movies Those noises were sometimes recorded.

As a noise countermeasure, it is possible to stop the zoom function, autofocus function, camera shake prevention function, etc. during movie shooting so as not to generate noise from the drive mechanism, but the function of the lens barrel is limited. This narrows the range of expression of shooting.
Therefore, Patent Document 1 includes two microphones, a voice recording microphone (hereinafter referred to as a microphone) and a noise detection microphone, and detects noise generated by the drive mechanism by the noise recording microphone, and the voice recording microphone. There has been proposed an electronic camera that reduces noise by subtracting a signal indicated by noise from the audio signal detected by the above method.

JP 2005-244613 A

  However, in the electronic camera of Patent Document 1, since the sound recording microphone and the noise recording microphone are arranged at different positions in the electronic camera, there is a phase difference in the sound detected from each microphone. Even if the noise signal detected by the noise recording microphone is subtracted from the audio signal detected by the voice recording microphone, there is a problem that the noise generated by the drive mechanism due to the phase difference cannot be reduced accurately.

  The present invention has been made to solve the above problems, and an object of the present invention is to provide an audio processing apparatus that improves the accuracy of reducing noise contained in an audio signal.

In order to solve the above problem, the present invention has the following solution. In addition, in order to make an understanding easy, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this.
(1) The present invention. A first microphone (111) whose sound collection direction is directed to the outside of the device (1) for recording, and a first microphone (111) provided near the first microphone (111) and directed to the inside of the device. Based on the sound signal output from the two microphones (112) and the first microphone (111) and the noise signal indicating the operation sound generated from the second microphone (112) and generated in the device. And a noise processing unit (120) that outputs a signal obtained by removing the noise signal from the audio signal.

(2) Further, the present invention is the speech processing apparatus (11) according to the above invention, wherein the noise processing unit (120) multiplies a predetermined noise coefficient and the noise signal, and a multiplication result Is subtracted from the audio signal and output.

  (3) Moreover, this invention is an electronic camera (1), Comprising: The audio | voice processing apparatus (11) of Claim 1 or Claim 2 is provided, The sound collection direction of the said 1st microphone (111) is the said It is directed to the outside of the electronic camera (1), and the sound collection direction of the second microphone (112) is directed to the inside of the electronic camera (1).

  (4) Further, the present invention is the electronic camera (1) according to the above invention, wherein the first and second microphones (111, 112) absorb vibration generated in the electronic camera (1). It is fixed to the electronic camera (1) via a vibration member (114).

  (5) Moreover, this invention is an electronic camera (1) as described in the said invention, Comprising: The said noise coefficient is matched with the said noise process part (120) for every lens-barrel (20) to which it is attached. A noise coefficient table (124) is provided, and a signal obtained by removing the noise signal from the audio signal is output using the noise coefficient corresponding to the attached lens barrel (20).

  (6) Moreover, this invention is an electronic camera (1) as described in the said invention, Comprising: According to the operation member (13) which outputs an operation signal, and the said operation signal which the said operation member (13) outputs A control unit (14) that outputs a driving signal for driving the driving unit (21) of the lens barrel (20), and the noise processing unit (120) includes the control unit (14). A signal obtained by removing the noise signal from the audio signal is output based on the audio signal and the noise signal in accordance with the timing of outputting the drive signal.

  According to the present invention, it is possible to improve the accuracy of reducing noise included in the detected audio signal.

It is a schematic block diagram which shows the structure of the electronic camera 1 by this embodiment. It is a schematic block diagram which shows the structure of the audio processing apparatus 11 in this embodiment. It is a figure which shows an example of calculation of the noise coefficient in the same embodiment. In the embodiment, it is a figure which shows an example of a process of the noise process part 120. FIG.

  Hereinafter, an audio processing apparatus and an electronic camera according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic block diagram showing the structure of the electronic camera 1 according to the present embodiment. As shown in FIG. 1A, the electronic camera 1 includes a camera body 10 and a lens barrel 20.

  The lens barrel 20 includes a drive unit 21 for a zoom function, an autofocus function, and a camera shake prevention function, and an optical lens 22. The drive unit 21 is, for example, a vibration wave motor, and is driven according to a drive signal input from the control unit 14 to move the optical lens 22 in the optical axis direction L and a direction perpendicular to the optical axis direction L. . Zooming, autofocusing, and camera shake prevention are performed by the drive unit 21 moving the optical lens 22. The lens barrel 20 normally includes a plurality of lens groups. Here, for simplification, one lens 22 is illustrated, and the case where the lens barrel 20 includes the optical lens 22 will be described.

The camera body 10 includes a sound processing device 11, an operation member 13, a control unit 14, an image sensor 15, and a memory 16.
The audio processing device 11 includes a microphone unit 110 and a noise processing unit 120. Further, the audio processing device 11 outputs an audio output signal in which noise included in the audio detected by the microphone unit 110 is reduced to the control unit 14 in the moving image mode for capturing a moving image. Here, the noise is a sound generated inside the electronic camera 1, for example, an operating sound of the drive unit 21.

  The operation member 13 includes a mode selection button for selecting a still image mode for capturing a still image and a moving image mode, a zoom selection button for selecting the zoom magnification of the lens barrel 20, and the like according to an operation from the user. The signal is output to the control unit 14. Here, the operation signal includes information indicating which one of the still image mode and the moving image mode is selected, information indicating the zoom magnification, and the like.

The control unit 14 outputs a drive signal to the drive unit 21 and the sound processing device 11 included in the lens barrel 20 according to the operation signal input from the operation member 13. Further, the control unit 14 outputs an output instruction signal to the audio processing device 11 when imaging in the moving image mode. This output instruction signal includes an instruction to cause the control unit 14 to output an audio output signal from the audio processing device 11.
Here, in the drive signal, function information indicating which of the zoom function, autofocus function, and camera shake prevention function the drive unit 21 operates and a drive indicating the drive amount of the drive unit 21 corresponding to the function. Information.

Further, in the moving image mode, the control unit 14 stores the sound output signal output from the sound processing device 11 and the moving image data output from the image sensor 15 in the memory 16 together.
The image sensor 15 photoelectrically converts a subject image formed through the optical lens 22 by a light receiving element and outputs image data indicating the subject image. The memory 16 stores captured moving image data and an audio output signal.

  FIG. 1B is a schematic diagram illustrating the configuration of the microphone unit 110. The microphone unit 110 is fixed to the camera body 10. In addition, the microphone unit 110 is fixed by contacting and fixing the external recording microphone (first microphone) 111, the noise detection microphone (second microphone) 112, the external recording microphone 111, and the noise detection microphone 112. A member 113 and a vibration damping member 114 that fixes the fixing member 113 to the camera body 10 are provided.

  The external recording microphone 111 is arranged so that the sound collection direction 111 a faces the outside of the electronic camera 1 and is exposed through the opening 10 a provided in the camera body 10 while being fixed to the camera body 10. The sound collection direction of the external recording microphone 111 is directed to the outside of the electronic camera 1 through the opening 10a. The noise detection microphone 112 is arranged so that the sound collection direction 112 a faces the inside of the electronic camera 1, and mainly detects sound generated inside the electronic camera 1. In this way, the sound collection direction 111a of the external recording microphone 111 and the sound collection direction 112a of the noise detection microphone 112 are arranged in opposite directions.

  Note that the external recording microphone 111 and the noise detection microphone 112 preferably have the same frequency characteristics. As a result, the output characteristics with respect to the noise generated inside the electronic camera 1 detected by the two microphones become the same, so that the effect of the subtraction processing performed by the audio processing device 11 described later can be made constant regardless of the frequency. And the accuracy of noise reduction can be improved.

The fixing member 113 is brought into contact with the external recording microphone 111 and the noise detection microphone 112 without any gap, and the two microphones are fixed in close contact with each other. The fixing member 113 is formed of hard plastic, metal, or the like so that vibration transmitted from the camera body 10 to the microphone unit 110 is similarly transmitted to the external recording microphone 111 and the noise detection microphone 112. And the noise detecting microphone 112.
In order to bring the external recording microphone 111 and the noise detection microphone 112 into close contact, the external recording microphone 111 and the noise detection microphone 112 may be fastened and fixed by a fixing member 113, or the external recording microphone 111 may be fixed. The noise detecting microphone 112 and the fixing member 113 may be bonded and fixed.

The vibration damping member 114 is made of a vibration damping material that converts vibration energy into heat energy and absorbs it, for example, a known vibration damping material (for example, butyl rubber, sponge, etc.) that uses rubber-based or resin-based viscoelasticity. The vibration transmitted from the camera body 10 to the fixing member 113 is reduced, and the vibration transmitted to the external recording microphone 111 and the noise detection microphone 112 is attenuated.
In FIG. 1B, the microphone unit 110 is fixed via the vibration damping member 114. However, the present invention is not limited to this, and a recess is provided in the camera body 10, and the microphone unit 110 is inserted into the recess. Alternatively, the camera body 10 may be provided with a holding portion, and the microphone portion 110 may be attached to the holding portion. In that case, a damping member 114 is interposed between the recessed portion or the sandwiching portion and the fixing member 113.

FIG. 2 is a schematic block diagram showing the configuration of the speech processing apparatus 11 in the same embodiment. As illustrated, the audio processing device 11 includes a microphone unit 110 and a noise processing unit 120. Moreover, the microphone unit 110 includes an external recording microphone 111 and a noise detection microphone 112 as shown in FIG.
The noise processing unit 120 includes an amplification unit 121 connected to the external recording microphone 111, a 122 connected to the noise detection microphone 112, a signal synthesis unit 123 connected to each of the amplification units 121 and 122, and a noise coefficient. Is stored in advance.

As for the noise coefficient, an operation sound (noise) generated by the drive unit 21 due to operations such as a zoom function, an autofocus function, and a camera shake prevention function of the electronic camera 1 is detected by the external recording microphone 111 and the noise detection microphone 112. It shows the ratio of the volume of sound.
FIG. 3 is a diagram illustrating an example of calculation of a noise coefficient in the embodiment. For example, the noise coefficient causes the external recording microphone 111 and the noise detection microphone 112 to detect noise generated by the driving unit 21 in an environment where sound other than noise generated by the driving unit 21 such as a soundproof room does not occur. At this time, the peak signal values of the audio signal output from the external recording microphone 111 and the noise signal output from the noise detection microphone 112 are measured, and the ratio of the peak peak values is used as the noise coefficient.

As shown in FIG. 3, in a situation where no external sound is detected, the peak peak value of the audio signal detected during the drive unit test drive period in which the drive unit 21 generates the operating sound is A, and the peak peak value of the noise signal If B is B, the noise coefficient is expressed by the following equation (1).
(Noise coefficient) = A / B (1)
The noise coefficient is calculated in advance for each zoom function, autofocus function, camera shake prevention function, and driving amount of each function.

The noise coefficient table 124 stores in advance the noise coefficient calculated as described above in association with the function and the driving amount.
When the electronic camera 1 can be removed and replaced, the noise coefficient table 124 includes a zoom function, an autofocus function, a camera shake prevention function, and a function for each lens barrel that can be attached. The noise coefficient associated with the driving amount is stored in advance.

  Returning to FIG. 2, as shown in FIG. 1B, the external recording microphone 111 is directed mainly toward the camera body 10 through the opening 10a provided in the camera body 10 so that the sound collection direction 111a is directed to the outside. A sound outside the body 10 is detected, and a sound signal indicating the detected sound is output to the amplifying unit 121. The noise detection microphone 112 has a sound collection direction 112a directed toward the inside of the camera body 10, and mainly detects a sound inside the camera body 10, particularly an operation sound of the drive unit 21, and a noise indicating the detected operation sound. The signal is output to the amplification unit 122.

  The audio signal amplified by the amplification unit 121 and the noise signal amplified by the amplification unit 122 are input to the signal synthesis unit 123, and the output instruction signal and the drive signal are input from the control unit 14. Further, when an output instruction signal is input from the control unit 14, the signal synthesis unit 123 outputs an audio output signal to the control unit 14. At this time, when the drive signal is not input from the control unit 14, the signal synthesis unit 123 outputs the amplified audio signal as an audio output signal to the control unit 14.

When a drive signal is input from the control unit 14, the signal synthesis unit 123 reads out the noise coefficient associated with the function information and the drive amount information included in the input drive signal from the noise coefficient table 124. , Multiplying the read noise coefficient by the amplified noise signal, subtracting the multiplication result from the amplified audio signal, and performing a synthesis process to reduce noise contained in the audio signal, and showing the result of the synthesis process An audio output signal is output to the control unit 14.
With the above-described configuration, the audio processing device 11 synthesizes the audio signal output from the external recording microphone 111 and the noise signal output from the noise detection microphone 112, thereby operating the drive unit 21 included in the audio signal. Sound (noise) is reduced and output to the control unit 14.

FIG. 4 is a diagram illustrating an example of processing of the noise processing unit 120 in the embodiment.
FIG. 4A is an example of a waveform diagram showing an amplified audio signal, FIG. 4B is an example of a waveform diagram showing an amplified noise signal, and FIG. 4C is a signal synthesis unit 123. It is an example of the waveform diagram of the audio | voice output signal which outputs. The signal synthesizer 123 detects a drive unit drive period in which the drive unit 21 generates an operating sound based on the input drive signal. The signal synthesizer 123 reads a noise coefficient corresponding to the input drive signal from the noise coefficient table 124, multiplies the read noise coefficient by the noise signal, and subtracts the multiplication result from the audio signal in the interval. As a result, the signal synthesis unit 123 performs a synthesis process for reducing noise components included in the audio signal, and outputs the synthesis result as an audio output signal.
In addition, the voice synthesizer 123 outputs the input voice signal as a voice output signal in a period other than the drive part drive period in which the drive signal is not input.

  In the electronic camera 1 configured as described above, the external recording microphone 111 and the noise detection microphone 112 are fixed by the fixing member 113 with the sound collection directions 111a and 112a being in opposite directions to each other. Each microphone can detect sound at substantially the same position, and a phase difference can be prevented from occurring in the signal output from each microphone. Thereby, the signal synthesis unit 123 can synthesize the audio signal detected by the external recording microphone 111 with the noise signal detected by the noise detection microphone 112 and the noise signal detected by the noise detection microphone 112, thereby reducing noise. It is possible to improve accuracy.

Further, since the external recording microphone 111 and the noise detection microphone 112 are fixed in contact with each other, vibration transmitted from the camera body 10 to the microphone unit 110 is similarly transmitted to the external recording microphone 111 and the noise detection microphone 112. Therefore, the same change can be applied to the signals output by the two microphones, and the noise caused by the vibration can be reduced efficiently.
In addition, since the external recording microphone 111 and the noise detection microphone 112 can detect voice and noise without phase difference, the signal synthesis unit 123 subtracts the result of multiplying the noise signal by the noise coefficient from the voice signal. The noise contained in the audio signal can be reduced without using complicated arithmetic processing.

  Further, the sound collection direction 111 a of the external recording microphone 111 is directed to the outside of the camera body 10 through the opening 10 a provided in the camera body 10, and the sound collection direction 112 a of the noise detection microphone 112 is directed to the inside of the camera body 10. As described above, the external recording microphone 111 can detect the sound outside the electronic camera 1, and the noise detection microphone 112 can detect the operating sound (noise) of the drive unit 21 inside the electronic camera 1, The noise included in the audio signal output from the external recording microphone 111 can be reduced, and the noise detection microphone 112 can output a noise signal reflecting the characteristics of the noise. The noise contained in the audio signal can be efficiently reduced based on the above.

In addition, since the microphone unit 110 is fixed to the camera body 10 via the vibration damping member 114, the vibration generated by the operation of the drive unit 21 transmitted to the microphone unit 110 via the camera body 10 can be reduced. In addition, noise included in the audio signal output from the external recording microphone 111 can be reduced.
In addition, since the noise coefficient corresponding to each lens barrel to be attached is stored in the noise coefficient table 124, the noise processing unit 120 can be used when the electronic camera 1 uses a different lens barrel. The sound signal and the noise signal can be synthesized using a noise coefficient corresponding to the operation sound and vibration of the drive unit included in the lens barrel, and noise included in the sound signal can be efficiently reduced.

  Further, since the signal synthesis unit 123 synthesizes the noise signal and the audio signal in accordance with the timing at which the drive signal for driving the drive unit 21 is output, when the drive unit 21 does not generate an operating sound. The synthesis of the noise signal and the audio signal can be avoided, and the processing amount performed by the noise processing unit 120 can be reduced.

In the present embodiment, the control unit 14 is configured to output a drive signal to the audio processing device 11 and cause the audio processing device 11 to read out the noise coefficient from the noise coefficient table 124. The drive signal may be encoded, and the noise coefficient may be read from the noise coefficient table 124 using the code.
In addition, the audio processing device 11 may include a signal synthesis unit 123 and an amplification unit that amplifies the audio output signal to be output. In the drive unit drive period, when the noise is reduced and the audio signal detected from the outside of the electronic camera 1 is somewhat reduced, the audio output signal is amplified by the amplification unit provided at the subsequent stage of the signal synthesis unit 123. Thus, it is possible to prevent the output level of the audio output signal in the drive unit driving period from becoming lower than the signals before and after the section.

  The above voice processing apparatus may have a computer system inside. In this case, the synthesis process performed by the signal synthesis unit described above is stored in a computer-readable recording medium in the form of a program, and the above process is performed by the computer reading and executing this program. Become. Here, the computer-readable recording medium means a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like. Alternatively, the computer program may be distributed to the computer via a communication line, and the computer that has received the distribution may execute the program.

  DESCRIPTION OF SYMBOLS 1 ... Electronic camera, 10 ... Camera body, 11 ... Audio | voice processing apparatus, 13 ... Operation member, 14 ... Control part, 20 ... Lens barrel, 21 ... Drive part, 111 ... External recording microphone, 112 ... Noise detection microphone , 114 ... Damping member, 120 ... Noise processing unit, 124 ... Noise coefficient table

Claims (6)

A first microphone whose sound collection direction is directed to the outside of the recording device;
A second microphone provided in the vicinity of the first microphone and having a sound collection direction directed to the inside of the device; an audio signal output from the first microphone; and an output of the device from the second microphone. An audio processing apparatus comprising: a noise processing unit that outputs a signal obtained by removing the noise signal from the audio signal based on a noise signal indicating an operation sound generated inside. The speech processing apparatus according to claim 1,
The noise processing unit multiplies a predetermined noise coefficient and the noise signal, and subtracts the multiplication result from the audio signal and outputs the result. An electronic camera,
The audio processing device according to claim 2,
An electronic camera, wherein the sound collection direction of the first microphone faces the outside of the electronic camera, and the sound collection direction of the second microphone faces the inside of the electronic camera. The electronic camera according to claim 3,
The electronic camera, wherein the first and second microphones are fixed to the electronic camera via a damping member that absorbs vibration generated in the electronic camera. An electronic camera according to claim 3 or claim 4, wherein
The noise processing unit includes a noise coefficient table in which the noise coefficient is associated with each attached lens barrel, and the noise signal is generated from the audio signal using the noise coefficient corresponding to the attached lens barrel. An electronic camera that outputs signals excluding The electronic camera according to claim 5,
An operation member for outputting an operation signal;
A control unit that outputs a drive signal for driving a drive unit included in the lens barrel in response to the operation signal output by the operation member;
With
The noise processing unit outputs a signal obtained by removing the noise signal from the audio signal based on the audio signal and the noise signal in accordance with a timing at which the control unit outputs the drive signal. Electronic camera.

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