DESCRIPTION JPH1132396

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DESCRIPTION JPH1132396
[0001]
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a
car navigation sound reproducing apparatus, and more particularly to a car navigation sound
reproducing apparatus for guiding a driver to a destination by voice.
[0002]
2. Description of the Related Art The principle of unnecessary sound suppression will be
described with reference to FIG. Active noise control technology for suppressing and removing
unwanted noise such as noise has been developed and put to practical use. To explain the
principle of this unnecessary sound suppression and removal technology with reference to FIG.
They are simultaneously generated through the circuit 41 and the speaker 42, and both sounds
are synthesized to cancel out unnecessary sounds. That is, FIG. 2 shows that the unnecessary
sound + n (t) is observed at the control point 43. When the unnecessary sound + n (t) is observed
at the control point 43, the sound of the opposite phase which becomes -n (t) is generated at the
control point 43 and the unnecessary sound can be canceled out by combining the both. As
described above, in order to cancel and remove the unnecessary sound, the antiphase sound
generation circuit 41 generates an acoustic signal −n (t) / h based on the observation result of
the unnecessary sound + n (t) by the observation microphone 431 and The unnecessary sound
source 40 is supplied. Here, h represents the sound transfer characteristic between the sound
source and the control point.
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[0003]
An active noise control headphone can be mentioned as an application example of the active
noise control technology mentioned above. When the listener wears this headphone, the listener
hears the sound from which all the extraneous sound around it has been removed. That is, all the
sounds other than the sound by the electric signal supplied to the headphones are to be removed.
In this case, there is a problem that even if there is an extraneous sound that is undesirable to be
eliminated in the extraneous sound, it is eliminated including this.
[0004]
From the above, when canceling out unwanted sounds, it is possible to selectively suppress only
specific acoustic components while leaving necessary acoustic components, and to limit the
suppression range of reproduced sound to other listeners. It is required not to affect the For
example, this corresponds to the case where the reproduction sound of the audio device and the
instruction sound of the route of the car navigation device are used in combination in the interior
of the car. The driver is requested to clearly listen to the instruction voice by leaving the
instruction voice of the route and suppressing the reproduction sound emitted from the audio
device. In order to satisfy the above-mentioned requirements, the conventional car navigation
apparatus adopts a configuration for reducing or blocking the volume of the reproduced sound
of the audio apparatus when giving a voice instruction of the route. According to this, the
suppression range of the reproduction sound of the audio device is continued over the entire car
cabin, and the reproduction sound of the audio device is interrupted every time the voice
instruction of the route is given, with the passenger other than the driver. And there is a problem
that it can not be heard. It is desirable that the reproduced sound of the audio device is not
suppressed at the passenger position.
[0005]
SUMMARY OF THE INVENTION When using an audio device and a car navigation device in
combination, the present invention provides the driver with a reproduction sound emitted from
the audio device during voice instruction of a route by the car navigation device. SUMMARY OF
THE INVENTION The present invention provides a car navigation sound reproducing apparatus
which solves the above-mentioned problem which does not suppress to the passenger while
suppressing.
[0006]
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An electric signal output from an audio unit 31 is input and has one or more first speakers 11 for
emitting sound, and the electric signal output from the audio unit 31 is processed. In a car
navigation sound reproducing apparatus having an adaptive filter and one or more second
speakers 12 for emitting an audio signal upon receiving an electrical signal for generating a
voice instruction, the adaptive filter is an audio signal near the driver. The car navigation sound
reproducing apparatus is configured to sequentially estimate the antiphase signal of the
component of the sound radiated from the first speaker 11 of the above, and add this to the
electric signal that generates the voice instruction.
[0007]
In the above car navigation sound reproducing apparatus, the car navigation sound reproducing
apparatus is configured to include the intermittent unit 23 that intermittently controls the
reverse phase signal according to the presence or absence of the voice instruction.
[0008]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT In suppressing audio sound when
audio sound and voice instructions for directions are simultaneously emitted, the present
invention is an anti-phase signal of a component of the sound signal in the vicinity of the driver
which is derived from the audio sound. An adaptive filter is provided to estimate.
And the speaker which inputs an antiphase signal and generates a sound is installed in the
driver's vicinity.
In addition, it has an interrupting portion for interrupting the reverse phase signal according to
the presence or absence of the voice instruction of the route.
[0009]
An embodiment of the present invention will be described with reference to FIG.
In FIG. 1, the unnecessary sound to be suppressed is an audio sound of one system and one
channel, and one audio speaker is used as an unnecessary sound source. 11 is an audio speaker,
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12 is a speaker near the driver, 13 is a microphone, 14 is an inverse filter, 15 is a subtraction
unit, 16 is a delay unit, 21 is an adaptive filter, 22 is a subtraction unit, 23 is an intermittent unit,
24 is addition Reference numeral 25 denotes a delay unit, 26 denotes a variable filter, 31
denotes an audio unit, and 32 denotes a car navigation unit. Among these, the microphone 13,
inverse filter 14, subtractor 15, delay unit 16, adaptive filter 21, subtractor 22, delay unit 25,
and variable filter 26 are reverse phase sound estimation units for estimating antiphase sound of
audio sound. Configured. Although one audio speaker 11 is used in FIG. 1, a plurality of audio
speakers 11 can be used.
[0010]
In the above car navigation sound reproducing apparatus, the flow of the sound signal indicated
by the solid line arrow will be described. The acoustic signal generated from the audio unit 31 is
input to the audio speaker 11, the variable filter 26, and the delay unit 25. Also, the acoustic
signal input to the delay unit 25 is input to the adaptive filter 21. Here, the audio speaker 11
generates and radiates audio sound, and the acoustic signal input to the variable filter 26 is
subjected to a convolution operation with the filter coefficient estimated in the adaptive filter 21
and output to the intermittent unit 23. The acoustic signal that has passed through the
intermittent unit 23 is supplied to the addition unit 24 and is added to the audio instruction
audio signal output from the car navigation unit 32. The acoustic signal obtained by the addition
is output to the inverse filter 14 and the delay unit 16. The output of the reverse filter 14 is
supplied to the driver vicinity speaker 12 for voice instruction. The inverse filter 14 sets the
coefficient that acts on the acoustic signal input to the driver vicinity speaker 12 as the inverse
characteristic of the sound transmission characteristic from the driver vicinity speaker 12 to the
microphone 13. The subtraction unit 15 subtracts the output supplied from the acoustic signal
observed and recorded by the microphone 13 through the delay unit 16 and outputs the result.
The delay unit 16 synchronizes the acoustic signal recorded by the microphone 13 and the
output supplied from the addition unit 24. Accordingly, the audio sound from the audio speaker
11 in the microphone 13 is estimated as the output from the subtraction unit 15. The subtracting
unit 22 subtracts the output of the adaptive filter 21 from the output of the subtracting unit 15
to generate an error signal for operating the adaptive filter 21. That is, the output of the
subtraction unit 15 serves as a reference signal, and the adaptive filter 21 estimates the value of
the acoustic transfer characteristic from the audio speaker 11 to the microphone 13 as a
coefficient acting on the acoustic signal. Here, the delay time of the delay unit 25 is made equal
to the delay time of the delay unit 16. Therefore, an antiphase sound to the audio sound from the
audio speaker 11 is estimated at the position of the microphone 13 as the output of the adaptive
filter 21. Therefore, the audio sound is suppressed at the position of the microphone 13 and the
voice instruction remains.
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[0011]
If the microphone 13 is placed at a position near the driver, the driver can be given an audio
sound suppression effect. Further, since the output for suppressing the audio sound emitted from
the driver vicinity speaker 12 may be weak, the effect of suppressing the audio sound is hardly
exerted on the passenger. This satisfies the requirement of not suppressing the audio sound at
the time of voice instruction to other occupants.
[0012]
In the above-described car navigation sound reproduction apparatus, the driver proximity
speaker 12, the microphone 13, the inverse filter 14, the subtraction unit 15, the delay unit 16,
the adaptive filter 21, the subtraction unit 22, the connection unit 23, the addition unit 24, the
delay unit 25, Two sets of variable filters 26 can be configured. Then, the audio signal input from
the audio unit 31 and the car navigation unit 32 is made common, and the operation of the
adaptive filter 21 is made independent. Also, the microphones 13 are installed near the driver's
ears. Thereby, the suppression effect of the audio sound in each driver's ear is improved. That is,
as the microphone 13 is placed closer to the driver, the suppression effect becomes more
remarkable, and the antiphase sound output for audio sound suppression can be further
weakened. Thus, the effects of audio sound suppression can be minimized for the passenger.
Furthermore, when the voice instruction is issued, the interruption unit 23 allows the passage of
an antiphase signal with the audio sound obtained by passing through the variable filter 26. On
the other hand, when there is no voice instruction, the reverse phase signal is cut off. In this case,
no sound is generated from the driver vicinity speaker 12, so the audio sound is not suppressed
at the driver position.
[0013]
As described above, in the car navigation sound reproducing apparatus of the present invention,
the first speaker and the second speaker are used, the audio sound is reproduced by the speaker
11, and the audio instruction is reproduced by the speaker 12. And the adaptive filter 21 which
estimates the antiphase signal of the component by the audio sound in driver | operator position
P sequentially is comprised. The speaker 12 generates a sound by inputting a signal indicating an
audio sound obtained by convolution of the filter coefficients estimated by the adaptive filter 21
and a signal instructing voice. In this case, the speaker 12 is preferably brought close to the
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driver position P.
[0014]
As an error signal for operating the adaptive filter 21, an input signal to the speaker 12 in which
the transfer characteristic between the speaker 12 and the microphone 13 is corrected from the
electric signal recorded by the microphone 13 in the vicinity of the driver position P Use the
signal from which the output electrical signal of has been subtracted. Here, the difference signal
of the input signal to the speaker 12 in which the transfer characteristic between the speaker 12
and the microphone 13 is corrected from the electric signal recorded in the vicinity of the driver
position P is derived from the speaker 11 in the vicinity of the driver position P It corresponds to
the component. Therefore, the component derived from the speaker 11 in the vicinity of the
driver position P as the output of the adaptive filter 21, that is, the contribution due to the audio
sound is estimated. Therefore, the filter coefficient estimated by the adaptive filter 21 is a value
obtained by exchanging the acoustic transfer characteristic between the speaker 11 and the
driver position P in the positive and negative directions. Since the adaptive operation of the
adaptive filter 21 is sequential, the audio sound is suppressed even if the acoustic transfer
characteristic between the speaker 11 and the driver position P fluctuates. However, the voice
instruction remains unsuppressed. Further, when the speaker 12 is installed close to the driver
position P, the output by the antiphase signal necessary for suppression may be weak. Therefore,
the influence of the suppression on the sound field is limited to the vicinity of the driver position
P, and the influence of the suppression hardly affects the passenger.
[0015]
The intermittent unit 23 intermittently controls the supply of the antiphase signal to the speaker
12 according to the presence or absence of the voice instruction. During voice instruction, the
antiphase signal is passed to the speaker 12. On the other hand, when there is no voice
instruction, the reverse phase signal is cut off. In this case, the audio sound is not suppressed at
the driver's position since the sound that cancels the audio sound is not emitted from the speaker
12.
[0016]
As described above, the car navigation sound reproducing apparatus according to the present
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invention sequentially estimates the antiphase signals of the components derived from the audio
sound in the vicinity of the driver position. As a result, since the component derived from the
audio sound is suppressed in the vicinity of the driver position, the driver can be made to clearly
listen to the voice instruction.
[0017]
The output may be weak if a speaker for generating a sound that generates an audio signal and
an anti-phase signal of a component derived from the audio sound is disposed close to the driver
position. Therefore, the influence of the audio sound suppression on the sound field can be
minimized except near the driver. Further, by intermittently controlling the reverse phase signal
of the component derived from the audio sound according to the presence or absence of the
audio instruction, the suppression of the audio sound in the vicinity of the driver position can be
limited to only during the audio instruction. Accordingly, the passenger can continuously listen to
the audio sound without being interrupted by the activation and cancellation of the suppression,
and the driver can listen to the audio sound when there is no voice instruction.
[0018]
Brief description of the drawings
[0019]
1 is a diagram for explaining an embodiment.
[0020]
2 is a diagram for explaining the principle of unnecessary noise suppression removal technology.
[0021]
Explanation of sign
[0022]
REFERENCE SIGNS LIST 11 audio speaker 12 driver proximity speaker 13 microphone 14
inverse filter 15 subtraction unit 16 delay unit 21 adaptive filter 22 subtraction unit 23
intermittent unit 24 addition unit 25 delay unit 26 variable filter 31 audio unit 32 car navigation
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unit
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