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JP2010166516

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DESCRIPTION JP2010166516
The present invention provides an acoustic processing apparatus that performs emphasis
processing and appropriate volume control processing on an acoustic signal. A sound volume
control unit includes: an emphasizing unit emphasizing a component to be emphasized of an
acoustic signal relative to a component not to be emphasized; and a sound volume control unit
performing sound volume control processing on the sound signal The sound processing
apparatus 62 switches the content of the volume control processing according to the processing
content of the emphasizing unit 61. [Selected figure] Figure 3
Sound processing apparatus, electronic apparatus equipped with the same, and sound processing
method
[0001]
The present invention relates to an acoustic processing apparatus that performs emphasis
processing and volume control processing on an acoustic signal, an electronic apparatus (for
example, an imaging apparatus or an IC recorder) including the acoustic processing apparatus,
and an acoustic processing method.
[0002]
Conventionally, various types of sound processing apparatuses have been proposed in which
volume control is performed on a reproduction sound signal according to the noise level of a
reproduction place when sound is reproduced under a noise environment (for example, Patent
Document 1 and Patent Reference 2).
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1
[0003]
The voice input / output device and program proposed in Patent Document 1 perform the noise
cancellation process on the transmission signal, and perform the volume control process on the
reception signal according to the canceled noise level. A volume control process is performed on
the reception signal according to the noise level at the reproduction place of the signal.
[0004]
Further, the automatic volume control device proposed in Patent Document 2 separately detects
the noise level at the reproduction place of the sound by the noise detection microphone, and
according to the noise level, to the sound signal inputted from the sound signal input means In
contrast, volume control processing taking into consideration human auditory characteristics is
performed.
[0005]
[Patent Document 1] Japanese Patent Application Publication No. 20008-34928 (Paragraph
0030, FIG. 1) Japanese Patent Application Publication No. H9-116361 (Paragraph 0018, FIG. 1)
[0006]
In the voice input / output device and program proposed in Patent Document 1, the level of noise
included in the transmission signal is not related to the level of noise that may be included in the
reception signal, and the volume control process for the reception signal is performed. Although
the noise reduction processing is not performed and the transmission signal is subjected to the
constant amplification processing by the amplifier and the noise reduction processing by the
noise canceller, the volume control processing is not performed.
That is, Patent Document 1 does not disclose or suggest an acoustic processing apparatus that
performs enhancement processing and volume control processing on a certain acoustic signal.
[0007]
In the automatic volume control device proposed in Patent Document 2, the level of noise
detected by the noise detection microphone and the level of noise that may be included in the
audio signal input from the audio signal input means are irrelevant and Although volume control
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2
processing is applied to the sound signal input from the signal input means, noise reduction
processing is not performed.
That is, Patent Document 2 does not disclose or suggest an acoustic processing apparatus that
performs enhancement processing and volume control processing on a certain acoustic signal.
[0008]
Furthermore, the automatic volume control device proposed in Patent Document 2 requires a
dedicated noise detection microphone for detecting the noise level at the reproduction place of
the sound, so the size and cost of the device increase. It was
[0009]
On the other hand, in an audio processing apparatus that performs enhancement processing and
volume control processing on an audio signal, there is a possibility that the effect of the
enhancement processing is not sufficiently reflected on the output signal of the sound processing
apparatus due to inappropriate volume control processing.
For example, if the enhancement process is a noise reduction process that emphasizes the nonnoise component of the acoustic signal relative to the noise component, the reduced noise
component may be increased again by the volume control process.
[0010]
An object of the present invention is to provide an audio processing apparatus that performs
enhancement processing and appropriate volume control processing on an audio signal, an
electronic device including the same, and an audio processing method.
[0011]
In order to achieve the above object, a sound processing apparatus according to the present
invention includes an emphasizing unit and a volume control unit, and the emphasizing unit
should emphasize an input acoustic signal or an acoustic signal output from the volume control
unit. The component is emphasized relative to the component not to be emphasized, and / or a
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3
predetermined band component of the input sound signal or the sound signal output from the
volume control unit is subjected to signal restoration processing to generate a restoration signal
To emphasize a predetermined element (for example, the pitch of a human voice) included in the
input sound signal or the sound signal output from the sound volume control unit, and the sound
volume control unit responds to the processing content of the emphasis unit. The contents of the
volume control process are switched.
Specifically, the content of the volume control processing may be switched according to the
processing content of the enhancement unit so that the volume control unit does not lose the
effect of the enhancement processing in the enhancement unit.
[0012]
In the sound processing apparatus according to the present invention, the volume control unit
switches the content of the volume control processing according to the processing content of the
enhancement unit, so for example, the enhancement processing makes the non-noise component
of the sound signal a noise component. On the other hand, in the case of noise reduction
processing to be emphasized relatively, it is possible to suppress that the reduced noise
component becomes large again by the volume control processing.
Therefore, the sound processing apparatus according to the present invention can perform
emphasis processing and appropriate volume control processing on the sound signal.
[0013]
Incidentally, in the present specification, “the emphasis on the component to be emphasized
relative to the component not to be emphasized” refers to a process that emphasizes the
component to be emphasized and does not emphasize or suppress the component to be
emphasized. A process to suppress a component to be emphasized that is not to be emphasized
or suppressed with respect to a component to be emphasized, and a process to emphasize a
component to be emphasized and to suppress a component to be emphasized are applicable.
Further, in the present specification, “to not impair the effect of the emphasizing process in the
emphasizing unit” does not mean only the case where the effect of the emphasizing process in
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the emphasizing unit is maintained 100%, and The case where the effect loss of the emphasizing
process in the emphasizing unit is improved as compared to the case where the content of the
volume control process is not switched according to the processing content of the emphasizing
unit is also included.
[0014]
In addition, the content of the volume control process may be switched according to at least one
of the frequency band processed by the enhancement unit, the control amount, and the time, for
example, the volume control unit.
[0015]
In addition, according to the processing content of the emphasizing unit, the volume control unit
may, for example, at least one of a frequency band for performing volume control, a volume
control amount for each frequency band, and a variation of the volume control amount per unit
time. May be switched.
[0016]
Further, in order to achieve the above object, an electronic device according to the present
invention includes the sound processing device having any one of the above configurations, and
has an audio recording and / or reproducing function.
[0017]
Further, as an example of the electronic device, there is an imaging device provided with a
camera for capturing an image.
[0018]
In order to achieve the above object, a sound processing method according to the present
invention includes an emphasizing step and a volume control step, and in the emphasizing step,
an input sound signal or an acoustic signal obtained by executing the volume control step.
Component to be emphasized is relatively emphasized with respect to the component not to be
emphasized, and / or a predetermined band component of the input sound signal or the sound
signal obtained by executing the volume control step is subjected to signal restoration processing
Generating a restoration signal to emphasize a predetermined element (for example, the pitch of
a human voice) included in the input sound signal or the sound signal obtained by performing
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the sound volume control step; The content of the volume control processing is switched
according to the processing content in the emphasizing step.
Specifically, the content of the volume control process may be switched according to the process
content of the enhancement step so as not to impair the effect of the enhancement process of the
enhancement step.
In the present specification, “do not lose the effect of the emphasizing process in the
emphasizing step” does not mean only maintaining 100% of the effect of the emphasizing
process in the emphasizing step, but not the above It also includes the case where the effect loss
of the emphasizing process in the emphasizing step is improved as compared with the case
where the content of the volume control process is not switched according to the process content
in the emphasizing step.
[0019]
According to the sound processing apparatus and the electronic apparatus having the same of
the present invention, the volume control unit switches the content of the volume control
processing according to the processing content of the emphasizing unit. When the noise
reduction processing emphasizes the noise component relative to the noise component, it is
possible to suppress that the reduced noise component becomes large again by the volume
control processing.
Therefore, the sound processing apparatus according to the present invention and the electronic
apparatus equipped with the same can perform enhancement processing and appropriate volume
control processing on the sound signal.
Further, according to the sound processing method of the present invention, the contents of the
volume control process are switched according to the contents of the process in the emphasizing
step. For example, the process in the emphasizing step compares the non-noise component of the
sound signal with the noise component. In the case of the noise reduction processing to
emphasize relatively, the reduced noise component can be suppressed from becoming large
again by the volume control processing.
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Therefore, the sound processing method according to the present invention can perform
emphasis processing and appropriate volume control processing on the sound signal.
[0020]
These are block diagrams which show the example of 1 internal configuration of the imaging
device which concerns on this invention. FIG. 2 is a schematic external view of the imaging
device shown in FIG. 1 as viewed from the top of the device. These are figures which show the
basic composition of a sound processing part. These are block diagrams which show the
structure of 1st Example of an acoustic processing part. These are block diagrams which show
the structure of 2nd Example of an acoustic processing part. These are figures showing
underwater noise. These are figures showing about the transition time of the amplification
degree in volume control start and volume control end. These are block diagrams which show the
structure of 1st Example of a sound-collection environment determination part. These are figures
which show the frequency characteristic of the sound in air. These are figures which show the
frequency characteristic of the sound in water. These are figures which show the difference in
the frequency characteristic of the sound in air and water. These are block diagrams which show
the structure of 2nd Example of a sound-collection environment determination part. These are
block diagrams which show the structure of 3rd Example of a sound-collection environment
determination part. Is a schematic diagram of a stereo microphone. These are block diagrams
which show the structure of 4th Example of a sound-collection environment determination part.
These are block diagrams which show the structure of 5th Example of a sound-collection
environment determination part. These are block diagrams which show the structure of 3rd
Example of an acoustic processing part. These are figures which show the outline | summary of
sound volume control in 3rd Example of a sound processing part. These are block diagrams
which show the structure of 4th Example of an audio processing part. These are figures which
show the outline | summary of sound volume control in 4th Example of a sound processing part.
These are block diagrams which show the example of another internal configuration of the
imaging device based on this invention.
[0021]
Embodiments of the present invention will be described below with reference to the drawings.
Here, as an electronic device according to the present invention, an imaging device capable of
recording and reproducing an image signal as well as recording and reproducing an acoustic
signal will be described as an example.
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[0022]
<< Basic Configuration of Imaging Device >> First, the basic configuration of the imaging device
will be described with reference to FIG. FIG. 1 is a block diagram showing an example of the
internal configuration of an imaging device according to the present invention.
[0023]
The imaging device shown in FIG. 1 includes a solid-state imaging device (image sensor) 1 such
as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) sensor
that converts incident light into an electrical signal, and an optical image of an object. A lens unit
2 having a zoom lens for forming an image on the image sensor 1, a motor for changing a focal
distance of the zoom lens, ie, an optical zoom magnification, and a motor for focusing the zoom
lens on an object AFE (Analog Front End) 3 that converts an image signal that is an analog signal
into a digital signal, a stereo microphone 4 that independently converts an acoustic signal input
from the left and right of the front of the imaging device into an electrical signal, An image
processing unit 5 for performing various image processing such as gradation correction on an
image signal to be a digital signal; An acoustic processing unit 6 that converts an acoustic signal
that is an analog signal from the Ike 4 into a digital signal and performs acoustic correction
processing, an image signal output from the image processing unit 5 and an acoustic signal
output from the acoustic processing unit 6 A compression processing unit 7 which performs
compression encoding processing such as MPEG (Moving Picture Experts Group) compression
method on each of the signals, and a compression encoded signal compressed and encoded by
the compression processing unit 7 in an external memory such as an SD card 22, a driver unit 8
for recording in 22, a decompression processing unit 9 for decompressing and decoding a
compression encoded signal read from the external memory 22 by the driver unit 8, and an
image signal obtained by decoding by the decompression processing unit 9 are analog Based on
a video output circuit unit 10 for converting into a signal, a video output terminal 11 for
outputting the signal converted by the video output circuit unit 10, and a signal from the video
output circuit unit 10 A display unit 12 having an LCD (Liquid Crystal Display) or the like for
displaying an image, an acoustic output circuit unit 13 for converting an acoustic signal from the
extension processing unit 9 into an analog signal, and a signal converted by the acoustic output
circuit unit 13 The sound output terminal 14 for outputting the sound, the speaker unit 15 for
reproducing and outputting the sound based on the sound signal from the sound output circuit
unit 13, and the timing generator for outputting the timing control signal for matching the
operation timing of each block TG) 16, a CPU (Central Processing Unit) 17 for controlling the
drive operation of the entire imaging apparatus, a memory 18 for storing each program for each
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operation and for temporarily storing data at the time of program execution, a user And an
operation unit 19 to which an instruction from a computer is input, and a bus for exchanging
data between the CPU 17 and each block It comprises a line 20, a bus line 21 for exchanging
data between the memory 18 and each block.
The CPU 17 drives each motor in the lens unit 2 according to the image signal detected by the
image processing unit 5 to control the focus and the aperture.
[0024]
<< Basic Operation of Imaging Device >> Next, the basic operation at the time of moving image
shooting of the imaging device shown in FIG. 1 will be described with reference to FIG. First, the
imaging device photoelectrically converts light incident from the lens unit 2 in the image sensor
1 to obtain an image signal which is an electrical signal. Then, the image sensor 1 sequentially
outputs an image signal to the AFE 3 in a predetermined frame cycle (for example, 1/60 seconds)
in synchronization with the timing control signal input from the timing generator 16.
[0025]
Then, the image signal converted from the analog signal to the digital signal by the AFE 3 is input
to the image processing unit 5. The image processing unit 5 converts an input image signal into
an image signal composed of a luminance signal and a color difference signal, and performs
various image processing such as gradation correction and contour emphasis. Further, the
memory 18 operates as a frame memory, and temporarily holds an image signal when the image
processing unit 5 performs processing.
[0026]
At this time, based on the image signal input to the image processing unit 5, in the lens unit 2,
the positions of various lenses are adjusted to adjust the focus, or the aperture is adjusted to
adjust the exposure. Be done. The adjustment of the focus and the exposure may be automatically
performed based on a predetermined program so as to be optimal, or may be performed
manually based on a user's instruction.
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[0027]
On the other hand, an acoustic signal to be converted into an electrical signal in the stereo
microphone 4 is input to the acoustic processing unit 6. The sound processing unit 6 converts an
input sound signal into a digital signal and performs sound correction processing such as noise
removal and intensity control of the sound signal. Although the configuration of the sound
processing unit 6 will be described later, illustration of an A / D conversion unit for converting an
input sound signal into a digital signal is appropriately omitted.
[0028]
Then, both the image signal output from the image processing unit 5 and the acoustic signal
output from the acoustic processing unit 6 are input to the compression processing unit 7 and
compressed by the compression processing unit 7 according to a predetermined compression
method. At this time, the image signal and the sound signal are temporally associated with each
other so that the image and the sound do not deviate at the time of reproduction. Then, the
compressed image signal and sound signal are recorded in the external memory 22 through the
driver unit 8.
[0029]
Further, in the case of recording only the sound, the sound signal is compressed by the
compression processing unit 7 according to a predetermined compression method and is
recorded in the external memory 22.
[0030]
The compression encoded signal recorded in the external memory 22 is read out to the
decompression processing unit 9 in accordance with the output signal of the operation unit 19
based on the user's instruction.
The decompression processing unit 9 decompresses and decodes the compression encoded
signal to generate an image signal and an acoustic signal. Then, the image signal is output to the
video output circuit unit 10 and the audio signal is output to the audio output circuit unit 13.
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Then, in the video output circuit unit 10 and the sound output circuit unit 13, the image signal
and the sound signal are converted into a format reproducible by the display unit 12 and the
speaker unit 15 and output.
[0031]
Further, in the so-called preview mode in which the user confirms the image displayed on the
display unit 12 without recording the image signal, the compression processing unit 7 does not
perform the compression process, and the image processing unit 5 The image signal may be
output to the video output circuit unit 10 instead of the compression processing unit 7. Also,
when recording an image signal, the image signal may be output to the display unit 12 through
the video output circuit 10 in parallel with the operation of recording in the external memory 22
through the driver unit 8. .
[0032]
In the configuration shown in FIG. 1, the display unit 12 and the speaker unit 15 are mounted in
the imaging device, but the display unit 12 and the speaker unit 15 are separated from the
imaging device and terminals (video output) provided in the imaging device It may be configured
to be connected to the terminal 11 and the sound output terminal 14) using a cable or the like.
[0033]
<< Arrangement of Stereo Microphone >> Next, an arrangement example of the stereo
microphone 4 provided in the imaging device shown in FIG. 1 will be described with reference to
the drawings.
FIG. 2 is a schematic external view of the imaging device shown in FIG. 1 viewed from the top of
the device. The monitor unit 23 is provided with the display unit 12 and the right and left
microphones 4R and 4L constituting the stereo microphone 4, and the lens unit 2 is provided on
the front of the main body. The right side microphone 4R and the left side microphone 4L are
provided on the back of the display unit 12 with a microphone interval of about 2 cm.
[0034]
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<< Basic Configuration of Sound Processing Unit >> The basic configuration of the sound
processing unit 6 is shown in FIG. The sound processing unit 6 relatively emphasizes the
component to be emphasized of the input sound signal with respect to the component not to be
emphasized, and / or generates a restored signal by performing signal restoration processing on
a predetermined band component of the input sound signal The emphasizing unit 61
emphasizing a predetermined element included in the input sound signal, and the volume control
unit 62 which receives the output signal of the emphasizing unit 61 and performs volume control
processing on the input signal. The emphasizing unit 61 sends information on the emphasizing
process content of the emphasizing unit 61 to the volume control unit 62, and the volume
control unit 62 switches the contents of the volume control process according to the
emphasizing process content of the emphasizing unit 61.
[0035]
According to such a configuration, the volume control unit 62 switches the content of the volume
control process according to the content of the enhancement process of the enhancement unit
61, so that, for example, the enhancement process makes the non-noise component of the
acoustic signal relative to the noise component. In the case of the noise reduction processing that
emphasizes the noise, it is possible to suppress that the reduced noise component becomes large
again by the volume control processing. Therefore, the sound processing unit 6 can perform
enhancement processing and appropriate volume control processing on the sound signal. More
specifically, the sound processing unit 6 can perform the volume control process so as not to
impair the effect of the emphasizing process in the emphasizing unit 61. In addition, since the
sound processing unit 6 does not need to provide a dedicated noise detection microphone for
detecting a noise level as in Patent Document 2, the size and cost of the device do not increase.
[0036]
<< First Embodiment of Sound Processing Unit >> A first embodiment of the sound processing
unit 6 will be described with reference to FIG. FIG. 4 is a block diagram showing the
configuration of the sound processing unit 6 when the first embodiment of the sound processing
unit 6 is adopted. In the first embodiment of the sound processing unit 6, the sound processing
unit 6 performs a wind noise reduction process on a sound signal (Rch sound signal, Lch sound
signal) collected by the stereo microphone 4; An output signal of the wind noise reduction unit
611 is input, and a volume control unit 621 that performs volume control processing on the
input signal is provided.
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[0037]
The wind noise reduction unit 611 sends information related to the wind noise reduction
processing content (a band including wind noise, information such as a level difference before
and after the wind noise reduction processing) to the volume control unit 621. The volume
control unit 621 has an equalizer function, and switches the content of the volume control
processing (degree of volume control of each band) according to the wind noise reduction
processing content. For example, when wind noise is present at 200 Hz to 300 Hz, the content of
volume control is switched according to the level difference before and after the wind noise
reduction processing in the same band. If the level difference between before and after the wind
noise reduction processing in the same band is equal to or less than a predetermined value, since
the influence of the wind is small, the same volume control as normal is performed. On the other
hand, when the level difference between before and after the wind noise reduction processing in
the same band is larger than the predetermined value, since the influence of the wind is large, the
lifting width of the volume is made smaller than usual. Thereby, volume control can be
performed without impairing the effect of wind noise reduction processing.
[0038]
When wind noise reduction processing is set to OFF in various settings of the imaging apparatus
shown in FIG. 1, an acoustic signal collected by the stereo microphone 4 passes through the wind
noise reduction unit 611 and the volume is generated. It is input to the control unit 621.
[0039]
<Example of Wind Noise Reduction Unit> Three examples of the wind noise reduction unit 611
will be given below.
[0040]
The frequency band in which wind noise is present is relatively low, and wind noise is generally
concentrated in a band of about 300 Hz or less.
In the first embodiment of the wind noise reduction unit 611, such characteristics are used to
reduce wind noise centering on a low band signal.
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That is, for each of the input Rch audio signal and Lch audio signal, the audio signal is separated
into a low band component and a higher band component using a high pass filter (HPF) and a
low pass filter (LPF) to obtain a low band signal. Reduce (or cut) and then add the two again.
[0041]
In the second embodiment of the wind noise reduction unit 611, the presence or absence of wind
noise is determined using the feature that "the wind noise has no cross correlation between the
left and right channel signals". Specifically, cross-correlation is obtained between the input Rch
acoustic signal and Lch acoustic signal, and it is determined that the acoustic signal includes
wind noise if the correlation value representing the cross-correlation is less than or equal to a
certain threshold. Do. In addition to simply determining the presence or absence of wind noise,
the obtained correlation value may also be used as an index indicating the strength of wind noise.
For example, a method may be adopted in which the degree of reduction of the low band signal is
varied according to the correlation value (see, for example, JP-A-11-69480).
[0042]
In the third embodiment of the wind noise reduction unit 611, 300 Hz is treated as a boundary, a
frequency band smaller than 300 Hz is treated as a "low band", and processing for reducing wind
noise is performed on the low band. However, although the intensity is relatively small, wind
noise also exists in a frequency band of 300 Hz or more and close to the low band. Therefore, in
the third embodiment of the wind noise reduction unit 611, the frequency band of 300 Hz or
more is further divided into a middle band and a high band to be treated, and processing for
reducing wind noise is also performed on the middle band. . As a specific numerical example, a
frequency band of 300 Hz or more and smaller than 1.5 kHz is treated as a "middle band", and a
frequency band of 1.5 kHz or more is treated as a "high band".
[0043]
The low band includes the frequency band of wind noise and is highly affected by wind noise, but
the low band includes important elements of sound. In particular, with regard to human voice,
the pitch (pitch frequency) of the voice is about 90 to 160 Hz for males and 230 to 370 Hz for
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females, and a very important factor in determining the sound quality is included in the low band
There is. The pitch is the fundamental frequency of the signal due to vocal cord vibration. If the
components of the band including such important elements are simply reduced or cut,
components of signal components different from wind noise will be reduced or cut, resulting in
distorted sound. In the case of human voice, the voice becomes smaller and the voice color
changes.
[0044]
Therefore, in the third embodiment of the wind noise reduction unit 611, the process for
reducing wind noise is divided into two stages, and each process is applied to different bands.
One of the two stages of processing is signal restoration processing that restores a signal that
does not include wind noise, and the other processing is signal reduction processing that reduces
wind noise by reducing the signal level.
[0045]
Signal restoration applies to low band signals. The low band contains strong wind noise as well as
an important element of sound, so noise reduction is achieved by restoring a signal that does not
contain wind noise, rather than reducing the signal level. When the signal restoration processing
is performed, it is not necessary to reduce the signal level, so that distortion of sound is less
likely to occur.
[0046]
In signal restoration processing, harmonics of voice and musical instrument sound are utilized to
generate a restoration signal for the low band from the mid band signal of the original signal.
[0047]
Harmonicity is a property in which the frequency spectrum is composed of an overtone
structure, and most of speech and instrument sounds have this property.
That is, assuming that the frequency of the lowermost component in the frequency spectrum of a
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certain sound is f0, the frequency spectrum of that sound is f0 and its overtone components f0
× 2, f0 × 3, f0 × 4, The frequency components of... Are formed. In this case, the frequency
component of f0 is called a fundamental wave component, and the frequency components of f0
× 2, f0 × 3, f0 × 4,... Are second-order, third-order, fourth-order,. It is called a harmonic
component.
[0048]
For harmonic signals, it is known that the fundamental wave component or the low-order
harmonic component can be restored from the high-order harmonic component, and this
restoration is nonlinear such as square processing, full-wave rectification, half-wave rectification,
etc. It is known that the process can be used (for example, JP-A-8-130494, JP-A-8-278800, JP-A9-55778).
[0049]
Signal reduction processing is applied to mid band signals.
Although the effect of wind noise on the mid band is small, if the wind noise reduction process is
not performed on the mid band, processing to reduce wind noise is performed only on the low
band. Sound remains and the user feels uncomfortable. However, since the effect of wind noise is
small, distortion of sound due to signal reduction is assumed to be small, and even if attention is
focused on elements of sound, the middle band is a band where harmonics of pitch exist, so even
if signal reduction is performed Less susceptible to distortion than low band. Therefore, as
described above, the signal reduction process is applied to the middle band signal.
[0050]
Although signal restoration processing may be applied to the mid band, in order to restore a mid
band signal not including wind noise, harmonic components in the high band signal are required.
Since such harmonic components are weak, good recovery is difficult. Therefore, signal reduction
processing is suitable for mid band signals.
[0051]
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Either of the signal restoration processing and the signal reduction processing may be performed
first, or each may be performed in parallel. Further, each of the signal restoration processing and
the signal reduction processing can be performed on the time axis or on the frequency axis.
When the third embodiment of the wind noise reduction unit 611 is adopted, signal restoration is
performed according to the information regarding the frequency band subjected to the signal
restoration processing from the sound enhancement unit 611 and the frequency band subjected
to the signal reduction processing from the sound volume control unit 621. It is desirable to
perform volume control so that the volume of the signal obtained by the process is not
suppressed or amplified, and the volume of the signal obtained by the signal reduction is not
amplified or suppressed.
[0052]
In addition, a wind noise determination unit that determines the presence or absence and
strength of wind noise may be provided. The wind noise determination unit determines, for
example, the presence or absence and strength of the wind noise by obtaining cross-correlation
between the left and right channels, and the determination result is used for signal restoration
processing and / or signal reduction processing. One wind noise determination unit may be
shared by signal restoration processing and signal reduction processing, or two wind noise
determination units may be provided, and the wind noise determination unit may be
independently provided for each of the signal restoration processing and the signal reduction
processing. May be assigned. When the wind noise determination unit is independently assigned
to each of the signal restoration processing and the signal reduction processing, it is also possible
to mutually use each determination result.
[0053]
<< Second Embodiment of Sound Processing Unit >> A second embodiment of the sound
processing unit 6 will be described with reference to FIGS. 5 to 16. FIG. 5 is a block diagram
showing the configuration of the sound processing unit 6 when the second embodiment of the
sound processing unit 6 is adopted. In the second embodiment of the acoustic processing unit 6,
the acoustic processing unit 6 performs an underwater noise reduction process on the acoustic
signal collected by the stereo microphone 4 and an output signal of the underwater noise
reduction unit 612. A sound volume control unit 622 that performs sound volume control
processing on the input signal and a sound collection environment determination unit 63 that
determines whether the sound signal is collected in water is provided.
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[0054]
In the various settings of the imaging apparatus shown in FIG. 1, the underwater noise reduction
process is set to OFF, or the two sound signals input to the sound processing unit 6 are not
collected in water. If 63 is determined, the acoustic signal collected by the stereo microphone 4
passes through the underwater noise reduction unit 612 and is input to the volume control unit
622. On the other hand, if the underwater noise reduction is set to ON and the sound collection
environment determination unit 63 determines that the two sound signals input to the sound
processing unit 6 are collected in water, stereo is selected. The acoustic signal collected by the
microphone 4 is input to the underwater noise reduction unit 612.
[0055]
The volume control unit 622 has a function of automatically suppressing the volume when the
level of the input acoustic signal is larger than a predetermined value.
[0056]
Usually, the underwater noise is a self-generated drive noise (drive noise of a motor that changes
the optical zoom magnification in the lens unit 2) and rubbing noise in the casing of the imaging
device shown in FIG. As shown in FIG. 6, the noise is often impulse noise.
Therefore, as volume control when there is underwater noise, it is desirable to make the
transition time of the amplification degree at the volume suppression start and the volume
suppression termination shorter than usual. Therefore, the underwater noise reduction unit 612
sends information on the time in which the underwater noise exists to the volume control unit
622, and the volume control unit 622 starts the volume suppression when there is underwater
noise according to the information on the time in which the underwater noise exists. The change
amount per unit time of the volume control amount at the end of the volume suppression is made
larger than usual to make the transition time of the amplification degree at the volume
suppression start and the volume suppression end shorter than usual.
[0057]
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18
FIG. 7 is a diagram showing transition time of amplification degree at the volume suppression
start and the volume suppression termination. In the normal volume suppression setting, the
transition time of the amplification degree at the volume suppression start and the volume
suppression end is too long for underwater noise, so when underwater noise is processed in the
normal volume suppression setting, underwater noise with a large level is included. Immediately
after the signal level can not be suppressed, the signal level becomes small immediately after the
large level underwater noise disappears. On the other hand, when underwater noise is present as
in the case of the volume control unit 622, when the underwater noise is processed by switching
from the normal volume suppression setting to the volume suppression setting for underwater
noise, the impulse signal level changes. Appropriate volume control can be performed
accordingly. Thus, the effect of suppressing underwater noise can be further obtained by
shortening the transition time of the amplification degree at the volume suppression start and
the volume suppression termination when there is underwater noise as compared to normal.
[0058]
<Example of Underwater Noise Reduction Unit> The underwater noise reduction unit 612, for
example, reduces underwater noise (impulse noise) by a smoothing process. As smoothing
processing, a method using an addition average value can be used. The addition average value x
'[f] used in this method is obtained by adding the signal value x [i] of each frequency i (Hz)
included in a certain frequency width Fa (Hz) centered on the frequency f (Hz). Is calculated by
dividing the sum by Fa. Specifically, it is obtained by the calculation formula shown in the
following formula (1).
[0059]
[0060]
Then, when the obtained added average value x '[f] is smaller than the signal value x [f], the value
of the added average value x' [f] is adopted as the signal value at the frequency f.
On the other hand, when the addition average value x '[f] becomes larger than the signal value x
[f], the value of the signal value x [f] is adopted as it is.
08-05-2019
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[0061]
In addition, in Formula (1), when calculating x '[f], each value of Fa (pieces) of x [f- (Fa / 2) +1]-x
[f + (Fa / 2)] is totaled It is also possible to sum the respective values of x [f- (Fa / 2)] to x [f + (Fa
/ 2) -1]. In the above example, Fa is an even number, but if Fa is an odd number, x [f-(Fa / 2) +
1/2] to x [f + (Fa / 2)-1/2] It is also possible to calculate the addition average value x '[f] by
summing the respective values of f and dividing by Fa.
[0062]
Furthermore, it is possible to cope with not only the noise appearing on the frequency axis but
also the noise appearing in the time axis direction by performing the smoothing process. In this
case, it is possible to apply the process using the addition average value similar to the equation
(1) described above. However, in this case, the average value is taken in the time axis direction.
[0063]
The added average value x '[t] to be determined is obtained by adding the signal value x [k] of
each time k (sec) included in a certain time width Ta (sec) centered on time t (sec) It is obtained
by dividing by Ta. Specifically, it is obtained by the calculation formula shown in the following
formula (2).
[0064]
[0065]
As in the case of reducing the noise appearing in the frequency axis direction described above,
when the obtained added average value x '[t] is smaller than the signal value x [t], the added
average value as a signal value at time t Adopt the value of x '[t].
On the other hand, when the addition average value x '[t] becomes larger than the signal value x
08-05-2019
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[t], the value of the signal value x [t] is adopted as it is.
[0066]
In equation (2), when calculating x ′ [t], each value of Ta (pieces) of x [t− (Ta / 2) +1] to x [t +
(Ta / 2)] is summed. It is also possible to sum the respective values of x [t- (Ta / 2)] to x [t + (Ta /
2) -1]. Further, although the example described above is the case where Ta is an even number, if
Ta is an odd number, x [t-(Ta / 2) + 1/2] to x [t + (Ta / 2)-1/2] It is also possible to calculate the
addition average value x '[t] by summing the respective values of x and dividing by Ta.
[0067]
In addition, as an example of the smoothing processing performed in the frequency axis direction
and the time axis direction, although the case of using the addition average value is shown, the
present invention is not limited to this method, and any other smoothing method can be used.
The method of may be used.
[0068]
First Embodiment of Sound Collection Environment Determination Unit Next, a first embodiment
of the sound collection environment determination unit 63 will be described with reference to
FIG.
FIG. 8 is a block diagram showing the configuration of the sound collection environment
determination unit 63 when the first embodiment of the sound collection environment
determination unit 63 is adopted. In the first embodiment of the sound collection environment
determination unit 63, the sound collection environment determination unit 63 includes a
frequency characteristic determination unit 631.
[0069]
Here, FIG. 9 shows frequency characteristics when white noise is reproduced in the air and
collected in the air. Also, FIG. 10 shows frequency characteristics when white noise is reproduced
in the air and collected in water.
08-05-2019
21
[0070]
The frequency characteristic when sound is collected in air is substantially flat as shown in FIG.
On the other hand, in the frequency characteristic when sound is collected in water, generally, if
the signal level is large, the signal in the high frequency band is largely attenuated as shown in
FIG. This is because the sound transmitted is attenuated by reflection at two boundaries of air-inwater and in-water-in-a-box (in-air) of a sound collection device, and the sound of a wave newly
generated in water and the case This is because generally a low sound such as a newly generated
sound remains inside.
[0071]
As described above, when the imaging device is used underwater, the low-band sound, the midband sound, and the high-band sound, which can not occur when the imaging device is used in
the air Because there is a level difference, the determination is made using the level difference.
[0072]
The frequency characteristic determination unit 631 is a low band (for example, several tens (70)
Hz to 3 kHz), an intermediate band (for example, 6 kHz to 9 kHz), and a high band (for example,
12 kHz to 15 kHz) for acoustic signals. To calculate the average value of the signal level.
The specific numerical value of each band is not limited to the above example, and there is no
problem if the magnitude relationship between the bands is correct. Also, the low band and the
mid band may partially overlap, and the mid band and the high band may partially overlap.
[0073]
Low band signal level ratio to high band (low band / high band) R1, low band signal level ratio to
mid band (low band / mid band), which can be calculated from the average value of the signal
level in each band ) R2 and the signal level ratio of middle band to high band (mid band / high
band) R3 show time changes as shown in FIG. 11 when the microphone is inserted from the air
into the water and returned to the air again . Periods T1 and T3 in FIG. 11 are periods in which
08-05-2019
22
the microphone is in the air, and period T2 in FIG. 11 is a period in which the microphone is in
the water. The signal level ratio of the middle band to the high band (middle band / high band)
R3 is a substantially constant value regardless of whether in air or water. On the other hand, the
signal level ratio of the low band to the high band (low band / high band) R1 and the signal level
ratio of the low band to the middle band (low band / mid band) R2 are small values in air. In the
water, the receiving sensitivity changes, and the value is much larger than in the air.
[0074]
Taking advantage of this, the frequency characteristic determination unit 631 sets the signal
level ratio of low band to high band (low band / high band) R1 and the signal level ratio of low
band to middle band (low band / mid band) R2. Calculated from average value of signal level in
each band, signal level ratio of low band to high band (low band / high band) R1 and signal level
ratio of low band to middle band (low band / middle band) R2 are preset When it becomes larger
than the threshold value, it is determined that the acoustic signal input to the acoustic processing
unit 6 is collected in water. Although the determination accuracy is inferior, the average signal
level in the middle band and the low band signal level ratio to the middle band (low band /
middle band) R2 are not calculated, and the low band signal level ratio to the high band ( It is
determined that an acoustic signal input to the acoustic processing unit 6 is collected in water
when the low band / high band) R1 becomes larger than a preset threshold, or a signal in a high
band Average value of level and low band signal level ratio (low band / high band) R1 to high
band are not calculated, and low band signal level ratio to middle band (low band / mid band) R2
is equal to or greater than a preset threshold It is also possible to determine that the acoustic
signal input to the acoustic processing unit 6 has been collected in water when it becomes large.
[0075]
Even under water, sudden noises are generated by the sound of air bubbles and the sound of the
casing, and the signal levels in the middle and high bands increase momentarily, and the signal
level ratio of the low band to the high band (low The band / high band) R 1 and the low band
signal level ratio to the middle band (low band / mid band) R 2 may become instantaneously
small. Therefore, the low band signal level ratio (low band / high band) R1 for the high band used
for the determination by the frequency characteristic determination unit 631 and the low band
signal level ratio (low band / middle band) R2 for the middle band are constant. It is desirable to
use an averaged value over time.
08-05-2019
23
[0076]
Further, with regard to the threshold, it is desirable to provide a hysteresis characteristic, to set
the threshold high while it is determined to be in the air, and to set the threshold low while it is
determined to be underwater.
[0077]
Second Embodiment of Sound Collection Environment Determination Unit Next, a second
embodiment of the sound collection environment determination unit 63 will be described with
reference to FIG.
FIG. 12 is a block diagram showing the configuration of the sound collection environment
determination unit 63 when the second embodiment of the sound collection environment
determination unit 63 is adopted. In the second embodiment of the sound collection environment
determination unit 63, the sound collection environment determination unit 63 includes a
propagation characteristic determination unit 632. The propagation characteristic determination
unit 632 is configured to collect an environment in which the input acoustic signal is collected
based on the difference between the propagation characteristic of the acoustic signal collected in
the air and the propagation characteristic of the acoustic signal collected in the water. Determine
[0078]
The propagation characteristics of the acoustic signal used by the propagation characteristic
determining unit 632 for the determination include, for example, the difference in the speed of
sound. The speed of sound in air is about 344 m / s, and the speed of sound in water is about
1500 m / s. In this example, the sound collection environment is determined based on the
difference in sound speed. In addition, when the determination is performed as described above,
for example, it is possible to use a drive sound of a motor provided in the lens unit 2 for
changing the optical zoom magnification. The case where the determination is performed as
described above will be described below.
[0079]
The CPU 17 controls the drive of the motor for changing the optical zoom magnification in the
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24
lens unit 2 according to the output of the operation unit 19. Further, the CPU 17 performs time
management on the drive timing of the motor for changing the optical zoom magnification in the
lens unit 2 and provides the information to the propagation characteristic judgment unit 632.
The drive sound of the motor for changing the optical zoom magnification in the lens unit 2 is
collected by the stereo microphone 4 as the drive sound (self-generated drive sound) in the
imaging device shown in FIG. Then, in the propagation characteristic determination unit 632, the
time information on the drive timing of the motor for changing the optical zoom magnification in
the lens unit 2 provided from the CPU 17 and the self-generated drive sound collected by the
stereo microphone 4 (lens unit 2 The transmission speed of the self-generated drive sound is
measured based on the sound collection time of the drive sound of the motor that changes the
optical zoom magnification in the above. In the imaging device shown in FIG. 1, since the
transmission speed of the self-generated driving sound in air is obtained in advance, it is possible
to determine whether the sound is collected in air or collected in water.
[0080]
Third Embodiment of Sound Collection Environment Determination Unit Next, a third
embodiment of the sound collection environment determination unit 63 will be described with
reference to FIG. FIG. 13 is a block diagram showing the configuration of the sound collection
environment determination unit 63 when the third embodiment of the sound collection
environment determination unit 63 is adopted. In the third embodiment of the sound collection
environment determination unit 63, the sound collection environment determination unit 63
includes a propagation characteristic determination unit 633. The propagation characteristic
determination unit 633 determines the environment in which the input acoustic signal is
collected based on the difference in propagation characteristics of the acoustic signal in air and
in water. However, the propagation characteristic determination unit 633 performs
determination using a method different from that of the propagation characteristic determination
unit 632 of the second embodiment shown in FIG.
[0081]
The determination method of the propagation characteristic determination unit 633 will be
described with reference to FIG. As shown in FIG. 14, when the sound emitted by the sound
source (sound from the direction of arrow A) is collected by the stereo microphone, a path
difference d is generated between the left side microphone 4L and the right side microphone 4R.
Then, due to the path difference d, a difference in arrival time (a value obtained by dividing the
path difference d by the speed of sound) is generated. In addition, because the difference in
08-05-2019
25
arrival time is different, between the acoustic signal (Rch) input from the right side microphone
4R to the acoustic processing unit 6 and the acoustic signal (Lch) input from the left side
microphone 4L to the acoustic processing unit 6 Phase difference occurs.
[0082]
And, as described above, the speed of sound is different between the air and the water. Therefore,
the phase difference generated between the acoustic signal (Rch) and the acoustic signal (Lch)
differs depending on the acoustic signal collected in the air and the acoustic signal collected in
the water. Therefore, the propagation characteristic determination unit 633 determines whether
the acoustic signal input to the sound collection environment determination unit 63 is collected
in water, based on the difference in phase difference.
[0083]
Fourth Embodiment of Sound Collection Environment Determination Unit Next, a fourth
embodiment of the sound collection environment determination unit 63 will be described with
reference to FIG. FIG. 15 is a block diagram showing the configuration of the sound collection
environment determination unit 63 when the fourth embodiment of the sound collection
environment determination unit 63 is adopted. In the fourth embodiment of the sound collection
environment determination unit 63, the sound collection environment determination unit 63
includes a pressure determination unit 634.
[0084]
When the fourth embodiment of the sound collection environment determination unit 63 is
adopted, a pressure sensor is newly provided in the imaging device shown in FIG. The pressure
determination unit 634 receives the detection signal of the pressure sensor, and when the
pressure outside the imaging device is equal to or greater than a preset threshold, the imaging
device is used in water, and the sound input to the acoustic processing unit 6 When it is
determined that the signal is collected in water and the pressure outside the imaging device is
less than a preset threshold, the imaging device is used in the air and is input to the sound
processing unit 6 It is determined that the acoustic signal is collected in air.
08-05-2019
26
[0085]
<Fifth Embodiment of Sound Collection Environment Determination Unit> Next, a fifth
embodiment of the sound collection environment determination unit 63 will be described with
reference to FIG. FIG. 16 is a block diagram showing the configuration of the sound collection
environment determination unit 63 when the fifth embodiment of the sound collection
environment determination unit 63 is adopted. In the fifth embodiment of the sound collection
environment determination unit 63, the sound collection environment determination unit 63
includes an image determination unit 635.
[0086]
The video determination unit 635 analyzes the video signal input from the image processing unit
5 and determines whether the imaging device is used underwater. For example, the video
determination unit 635 inputs a video signal before white balance adjustment from the image
processing unit 5, analyzes the color distribution of the video signal before white balance
adjustment, and determines whether the imaging device is used underwater. judge.
[0087]
Note that the video determination unit 635 may not be provided in the sound processing unit 6
but in the image processing unit 5, and the sound collection environment determination unit 63
may input the determination result of the video determination unit 635.
[0088]
<< Third Embodiment of Sound Processing Unit >> A third embodiment of the sound processing
unit 6 will be described with reference to FIGS. 17 and 18.
FIG. 17 is a block diagram showing the configuration of the sound processing unit 6 in the case
where the third embodiment of the sound processing unit 6 is adopted. In the third embodiment
of the sound processing unit 6, the sound processing unit 6 performs directivity control
processing on the sound signal collected by the stereo microphone 4, and an output signal of the
directivity control unit 613. And a volume control unit 623 that performs volume control
processing on the input signal.
08-05-2019
27
[0089]
The directivity control process is a process of analyzing phase information of a stereo input
signal for each band and extracting only a signal of a specific phase.
[0090]
The directivity control unit 613 sends the phase information to the volume control unit 623.
The volume control unit 623 has an equalizer function, and according to the phase information
from the directivity control unit 613, the signal of the band extracted in the directivity control
process is not suppressed or amplified. The volume control is performed so as not to amplify the
volume of the signal of the band extracted in the process or to suppress the volume (see FIG. 18).
Thereby, volume control can be performed without impairing the effect of directivity control
processing. Further, the effect of directivity control can be further enhanced by amplifying the
volume of the signal of the band extracted in the directivity control process and suppressing the
signal of the band not extracted in the directivity control process.
[0091]
When directivity control processing is set to OFF in the various settings of the imaging apparatus
shown in FIG. 1, the sound signal collected by the stereo microphone 4 passes through the
directivity control unit 613 to obtain the volume. It is input to the control unit 623.
[0092]
<Example of directivity control unit> For example, directivity control in which directivity is given
in a direction within 30 ° to the left and right from the front direction of the imaging device will
be described.
[0093]
The directivity control unit 613 first samples the Rch acoustic signal input from the right side
microphone 4R (see FIG. 14) of the stereo microphone 4 at 48 kHz and converts it into a digital
signal, and then performs FFT (Fast Fourier Transform) every 2048 samples. ) Converts the Lch
acoustic signal input from the left side microphone 4L (see FIG. 14) of the stereo microphone 4
at 48 kHz and converts it into a digital signal, and converts it into a digital signal every 2048
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28
samples. The signal is converted to a signal SL [F] in the frequency domain by FFT processing.
[0094]
Next, the directivity control unit 613 compares the phase difference between the signal SR [F] in
the frequency domain and the signal SL [F] in the frequency domain, and determines the phase of
the sound reaching the right microphone 4R and the left microphone 4L. Information of relative
phase difference which is the difference with the phase of the reached sound is generated.
The relative phase difference comparing unit 662 obtains a relative phase difference every
2048/48000 Hz which is the resolution of the FFT units 61R and 61L.
[0095]
In order to uniquely determine the relative phase difference between the two acoustic signals
collected by the two microphones, it is necessary for the distance between the two microphones
to be an acoustic signal at a frequency equal to or less than a half wavelength.
Therefore, when the distance between two microphones is approximately 2 cm as shown in FIG.
2, the relative phase difference information generation unit 662 generates an acoustic signal in a
band of 8.5 kHz or less, assuming that the speed of sound in air is 340 m / s. The relative phase
difference information can be generated only for.
[0096]
Further, the directivity control unit 613 sets relative phase difference information from the
relative phase difference information generation unit 662 and the first threshold (for each of
2048/48000 [Hz], which is the resolution of the FFT units 661R and 661L (see below. 3) If the
relative phase difference information from the relative phase difference information generation
unit 662 is larger than the first threshold value (Δφ1 of the equation (3) shown below) in
comparison with Δφ1 of the equation, the signal SR in the frequency domain It is determined
that [F] and SL [F] are caused by a sound source (unwanted sound) having a sound source
direction angle θR or θL (see FIG. 14) larger than 30 °, and a sound source direction angle θR
08-05-2019
29
or θL is a sound source larger than 30 ° The frequency component determined to be due to
(unwanted sound) is reduced by -20 dB, and the relative phase difference information from the
relative phase difference information generation unit 662 is equal to or less than the first
threshold (Δφ1 in equation (3) shown below) In the frequency domain It is determined that SR
[F] and SL [F] are due to a sound source with a sound source direction angle θR or θL (see FIG.
14) within 30 °, and the sound source direction angle θR or θL is with a sound source within
30 ° A process is performed that does not reduce frequency components determined to be
present.
However, Freq in equation (1) is a frequency to be compared with relative phase difference
information. Δφ1 = 2π × (Freq × 20 × sin 30 ° / 340000) (3)
[0097]
However, while the speed of sound in air is approximately 344 m / s, the speed of sound in water
is approximately 1500 m / s. Therefore, also in the third embodiment of the sound processing
unit, the sound collection environment determination unit provided in the second embodiment of
the sound processing unit is provided, and the two sound signals input to the sound processing
unit 6 are collected in water If it is determined that the sound collection environment
determination unit determines that the sound collection environment has not been collected, it is
determined that the two sound signals input to the sound processing unit 6 are collected in water
using the above equation (3). If the determination unit makes a determination, it is preferable to
use the following (4) instead of the above (3). Δφ1 = 2π × (Freq × 20 × sin 30 ° /
1500000) (4)
[0098]
The volume control unit 623 may control the volume of the signal in the frequency domain
output from the directivity control unit 613, and then convert it into a signal in the time domain
by IFFT (Inverse Fast Fourier Transform) processing and output it. The signal may be output as it
is in the frequency domain.
[0099]
<< Fourth Embodiment of Sound Processing Unit >> A fourth embodiment of the sound
processing unit 6 will be described with reference to FIGS. 19 and 20. FIG.
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30
FIG. 19 is a block diagram showing the configuration of the sound processing unit 6 when the
fourth embodiment of the sound processing unit 6 is adopted. In the fourth embodiment of the
sound processing unit 6, the sound processing unit 6 inputs a voice emphasizing unit 614 that
performs voice emphasizing processing on the sound signal collected by the stereo microphone 4
and an output signal of the voice emphasizing unit 614, And a volume control unit 624 that
performs volume control processing on the input signal.
[0100]
The speech enhancement process is a process of increasing the signal level of the resonance
frequency of the voice called formant and reducing the other signal levels.
[0101]
The voice emphasizing unit 614 sends information on the formant frequency band to the volume
control unit 624.
The volume control unit 624 has an equalizer function, and according to the information on the
formant frequency band from the voice emphasizing unit 614, the signal of the formant
frequency band is not suppressed or amplified in volume, and the signal of the band other than
the formant frequency is The volume control is performed so as not to amplify the volume or to
suppress the volume (see FIG. 20). As a result, volume control can be performed without losing
the effect of the speech enhancement processing. In addition, by amplifying the volume of the
signal of the formant frequency band and suppressing the volume of the signal of the band that
is not the formant frequency, the effect of voice emphasis can be further enhanced.
[0102]
When the sound enhancement processing is set to off in the various settings of the imaging
apparatus shown in FIG. 1, the sound signal collected by the stereo microphone 4 passes through
the sound enhancement unit 614 and the volume control unit It is input to 624.
[0103]
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31
<< Modifications >> In the first to fourth embodiments of the sound processing unit described
above, the volume control unit is the enhancement unit (wind noise reduction unit, underwater
noise reduction unit, directivity control unit, or voice enhancement unit) However, the volume
control unit may be provided before the emphasizing unit.
In the configuration in which the volume control unit is at the front stage of the emphasizing
unit, the control information in the block at the rear stage is fed back to the volume control unit
at the front stage to perform volume control processing. Information on the emphasis processing
content of the emphasizing unit in the latter stage may be fed back to the volume control unit in
the former stage, and the volume control unit in the former stage may switch the content of the
volume control process according to the emphasizing processing content of the emphasizing unit
in the latter stage. However, in the configuration where the volume control unit precedes the
emphasizing unit, a time lag occurs in switching of the content of the volume control processing,
so it is preferable to have the volume control unit downstream of the emphasizing unit.
[0104]
Furthermore, the present invention may be implemented in a form in which some of the first to
fourth embodiments of the sound processing unit described above are combined. For example,
the directivity control unit may be provided downstream of the wind noise reduction processing
unit, and the volume control unit may be provided downstream of the directivity control unit.
[0105]
The imaging apparatus shown in FIG. 1 described above includes an acoustic processing unit that
performs enhancement processing and volume control processing on the acoustic signal when
recording the collected acoustic signal. However, the present invention is not limited to this, and
may include an audio processing unit that performs enhancement processing and volume control
processing on the acoustic signal when reproducing the collected acoustic signal.
[0106]
FIG. 21 shows an imaging apparatus including an acoustic processing unit that performs
enhancement processing and volume control processing on the acoustic signal when reproducing
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32
the collected acoustic signal. In FIG. 21, the same reference numerals as in FIG. 1 denote the
same parts in FIG.
[0107]
21 differs from the imaging device shown in FIG. 1 in that an acoustic processing unit 6a is
provided instead of the acoustic processing unit 6, and further, acoustic processing is performed
between the extension processing unit 9 and the acoustic output circuit unit 13. The point is that
the portion 6 b is provided.
[0108]
Unlike the sound processing unit 6, the sound processing unit 6a performs A / D conversion
processing but does not perform enhancement processing and volume control processing on the
sound signal.
[0109]
The sound processing unit 6 b has the same configuration as the sound processing unit 6 except
that the A / D conversion process is not performed.
The sound processing performed in the sound processing unit 6b is basically the same as the
sound processing performed in the sound processing unit 6, and thus the description thereof is
omitted here.
[0110]
The sound collection environment (the environment where the imaging device shown in FIG. 21
is placed at the time of sound collection) and the reproduction environment (the environment
where the imaging device shown in FIG. 21 is placed at the time of reproduction) may be
different. Therefore, the fourth embodiment of the sound collection environment judgment unit
described above is not adopted in the sound collection environment judgment unit of the sound
processing unit 6b.
[0111]
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33
In addition, since the electronic device according to the present invention only needs to be able
to record and / or reproduce an audio signal, a block relating to video is not particularly
necessary.
Therefore, the present invention can be applied to electronic devices other than the imaging
device, for example, an acoustic recording device, an acoustic reproducing device, an acoustic
recording and reproducing device (for example, an IC recorder), and the like.
[0112]
In addition, although it is desirable that the electronic device equipped with the sound collection
environment determination device has a waterproof structure, even if it is not a waterproof
structure, for example, it is housed in a waterproof housing and receives an acoustic signal
collected by an external hydrophone It is possible to adopt various usages.
[0113]
In addition, for example, the electronic device according to the present invention can be realized
by operating reproduction software including a program for causing a computer to function as
each unit of the sound processing unit 6b on a personal computer.
[0114]
Further, the present invention is not limited to the case described above, and the imaging device
and the sound processing units 6, 6a and 6b of FIGS. 1 and 21 can be realized by hardware or a
combination of hardware and software.
When the imaging apparatus and the sound processing units 6, 6a and 6b of FIGS. 1 and 21 are
configured using software, the block diagram for the portion realized by the software represents
a functional block diagram of the portion Do.
[0115]
Further, the present invention is not limited to the above case, and microphone arrays of other
channels (for example, microphones compatible with 5.1ch surround sound recording) may be
used instead of the stereo microphone 4.
08-05-2019
34
[0116]
Further, in the image pickup apparatus photographing of FIG. 1, a normal photographing mode
which is a photographing mode suitable for the image pickup apparatus in the air and an
underwater photographing mode which is a photographing mode suitable for the image pickup
apparatus in the water; It does not matter as a structure which a user can switch manually by
operation of the operation part 19. FIG.
Also in this case, the sound collection environment determination unit 63 may determine
whether the sound signal input to the sound processing unit 6 is collected in water or not. Either
of the photographing mode automatically set by the determination result of 63 and the
photographing mode manually set by the operation of the operation unit 19 may be prioritized.
In addition, it is desirable that change between the automatically set photographing mode and
the manually set photographing mode can be made by the operation of the operation unit 19.
[0117]
In addition, when it is determined in the image pickup device photographing in FIG. 21 that the
sound collection environment determination unit of the sound processing unit 6b collects sound
in water, the reproduction mode is suitable for reproduction of an acoustic signal collected in
water. In the underwater reproduction mode, when it is determined that the sound collection
environment determination unit of the sound processing unit 6b collects the sound in air, the
normal reproduction mode which is a reproduction mode suitable for reproduction of the sound
signal collected in the air However, instead of or in addition to this, the configuration may be
such that the user can manually switch between the underwater regeneration mode and the
normal regeneration mode by operating the operation unit 19.
As in the latter case, when the manual switching configuration is added, either of the
automatically set reproduction mode and the manually set reproduction mode by the operation
of the operation unit 19 may be prioritized. Note that it is desirable to be able to change which of
the automatically set reproduction mode and the manually set reproduction mode is prioritized
by the operation of the operation unit 19.
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[0118]
As mentioned above, although embodiment concerning this invention was described, the scope of
this invention is not limited to this, A various change can be added and implemented in the range
which does not deviate from the main point of invention.
[0119]
Reference Signs List 1 solid-state imaging device (image sensor) 2 lens unit 3 AFE 4 stereo
microphone 4L left microphone 4R right microphone 5 image processing unit 6, 6a, 6b acoustic
processing unit (an example of acoustic processing apparatus) 7 compression processing unit 8
driver unit 9 extension Processing unit 10 Video output circuit unit 11 Video output terminal 12
Display unit 13 Sound output circuit unit 14 Sound output terminal 15 Speaker unit 16 Timing
generator (TG) 17 CPU 18 Memory 19 Operation unit 20, 21 Bus line 22 External memory 23
Monitor unit 61 Emphasizing Unit 62 Volume Control Unit 63 Sound Collection Environment
Determination Unit 611 Wind Noise Reduction Unit 612 Underwater Noise Reduction Unit 613
Directivity Control Unit 614 Voice Enhancement Unit 621 -624 Volume Control Unit 631
Frequency Characteristic Determination Unit 632, 633 Propagation Characteristic Determination
Unit 634 Pressure judgment unit 635 The determination unit
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