JP2008164747

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DESCRIPTION JP2008164747
To perform tuning of a voice acquisition unit of a voice recognition robot efficiently. A voice
recognition robot 100 performs tuning on a microphone array 180 functioning as a voice
acquisition unit, a speaker 170 functioning as a voice output unit, a robot arm 160 on which the
speaker 170 is mounted, and the microphone array 180. It has a tuning unit to do. The tuning
unit has a tuning control unit that causes the speaker 170 to output a reference sound at the
time of tuning, and a tuning execution unit that executes tuning using a response of the sound
acquisition unit to the reference sound. [Selected figure] Figure 1
Speech recognition robot
[0001]
The present invention relates to a voice recognition robot, and more particularly to a voice
recognition robot having a function of tuning its voice acquisition unit.
[0002]
Robots are expanding their scope to offices and homes regardless of where industrial or
production activities occur.
In the field of industrial activities and production activities, we substitute or support various
difficult industries, and emulate the movement mechanism and emotional expression of relatively
intelligent walking animals such as people and pets in the home, Co-exist with humans. Many of
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these robots do not operate only in a predetermined pattern as in conventional robots, but are
so-called autonomous ones that analyze situations and act. As an example of an autonomous
robot, there is a voice recognition robot that has a voice recognition function, analyzes voice
instructions, and performs the instructed operation.
[0003]
Usually, in the environment where the voice recognition robot is placed, other voices (noises) are
mixed in addition to the voice of the instruction. In order to prevent the malfunction of the voice
recognition robot, it is necessary to receive the voice of the instruction correctly, and various
attempts have been made for that.
[0004]
Patent Document 1 discloses a technique for making it easier to receive a target voice than noise.
According to this technique, when a voice instruction is given, the voice recognition robot
estimates the sound source direction of the voice command, moves to the estimated sound
source direction, and approaches the sound source, thereby making the voice of the voice
command another voice. It is made to be able to receive sound stronger than.
[0005]
Further, Patent Document 2 discloses a technology of diagnosing by a robot itself whether or not
a part for acquiring a voice (hereinafter referred to as a voice acquisition unit) is operating
properly. Specifically, in the vicinity of a voice acquisition unit, for example, a microphone,
contact sound or striking sound is generated using both left and right robot arms, and it is
confirmed whether or not the microphone can collect sound. If the check result is NG, the robot
arm performs a gesture such as swinging a neck while pointing at the microphone to notify the
user that there is a problem with the microphone. JP, 2006-181651, A JP, 2002-144260, A
[0006]
The technology disclosed in Patent Document 1 is premised on the voice acquisition unit
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operating correctly. Whether or not the voice acquisition unit is operating correctly can be
represented, for example, by whether or not it is an ideal directivity pattern as designed. The
tuning for the voice acquisition unit to be an ideal directivity pattern is usually performed by an
engineer.
[0007]
Further, although the technology disclosed in Patent Document 2 can notify the user that there is
a problem, tuning for solving the problem is also left to the user or engineer.
[0008]
At the development stage of the speech recognition robot, the number of units is small, so the
engineer does not burden the tuning of the speech acquisition part so much, but in the mass
production stage, automation is required due to factors such as man-hours and costs.
[0009]
In addition, even after the voice recognition robot reaches the user, tuning of the voice
acquisition unit is necessary.
If the engineer visits the use site every time the tuning is performed, the user is burdened with
money and time.
Automatic tuning of the voice acquisition unit of the voice recognition robot is desired also by
the user.
[0010]
The tuning of the voice acquisition unit such as a microphone requires a reference sound source
for outputting a reference voice. It is no exaggeration to say that it is possible to automate tuning
depending on whether or not there is an effective provision method of the reference sound
source. Here, a method of setting a reference sound source at a predetermined place and moving
the voice recognition robot to a position close to the reference sound source at the time of tuning
will be considered. If a tuning function is implemented on the main body of the voice recognition
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robot, automatic tuning of the voice acquisition unit becomes possible if the voice recognition
robot moves close to the reference sound source. However, this method has a problem that the
number of processes increases at the production stage because the movement of the robot is
accompanied, which is not efficient. In addition, a place for installing a reference sound source is
also required.
[0011]
In tuning after passing to the user, installation and maintenance of the reference sound source in
the actual use environment is also a burden on the user.
[0012]
The present invention has been made in view of the above circumstances, and realizes the
automatic tuning of the voice acquisition unit of the voice recognition robot efficiently and
conveniently.
[0013]
A voice recognition robot according to the present invention includes a voice acquisition unit, a
voice output unit, a mounting unit on which the voice output unit is mounted, and a tuning unit
that performs tuning on the voice acquisition unit.
The tuning unit has a tuning control unit that causes the voice output unit to output a reference
voice when performing tuning, and a tuning execution unit that performs tuning using a
response of the voice acquisition unit to the reference voice.
According to the present invention, since the voice recognition robot is provided with the voice
output unit and the tuning unit, at the time of tuning, the tuning unit causes the voice output unit
to output the reference voice, and the response of the voice acquisition unit to the reference
voice Can be tuned using Therefore, there is no need to secure the installation place of the
reference sound source or move the voice recognition robot for tuning, which is convenient and
efficient.
[0014]
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The present invention can be applied to a speech recognition robot in which the speech
acquisition unit is a microphone array including a plurality of microphones. In this case, the
tuning execution unit executes calibration for eliminating variations in sensitivity characteristics
of the plurality of microphones.
[0015]
The mounting unit in the voice recognition robot according to the present invention includes a
displacement unit configured such that the voice output unit mounted thereto can displace the
relative position with respect to the voice acquisition unit, and the tuning control unit outputs the
voice to the voice acquisition unit It is preferable to cause the voice output unit to output a
reference voice after displacing the displacement unit so that the relative positional relationship
between the units becomes a predetermined positional relationship. With such a configuration,
for example, the audio output unit can be moved to a position suitable for tuning of the audio
acquisition unit.
[0016]
Moreover, as this displacement part, it is preferable to comprise with the robot arm provided
with one or more joints, and the drive part which drives this robot arm. The voice recognition
robot usually has a robot arm, and if the voice output unit is attached thereto, there is no need to
separately provide a mechanism for attaching the voice output unit.
[0017]
In addition, the tuning control unit causes the displacement unit to be displaced a plurality of
times so that the relative positional relationship between the voice acquisition unit and the voice
output unit respectively becomes a plurality of different predetermined positional relationships.
The reference voice is output to the voice output unit each time the relative positional
relationship of the voice output unit becomes a predetermined positional relationship, and the
tuning execution unit performs tuning each time the voice reference unit is output from the voice
output unit. It is preferable to combine the results of multiple tunings. According to such a
configuration, a better tuning effect can be obtained particularly when the sound acquisition unit
is a microphone array.
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[0018]
Furthermore, it is preferable that the tuning control unit causes the voice output unit to
sequentially output a plurality of reference voices having mutually different frequencies, and the
tuning execution unit executes tuning for each frequency of the reference voice. Since the
characteristics such as the sensitivity of the voice acquisition unit may differ depending on the
frequency of the received voice signal, if the tuning is performed for each frequency with such a
configuration, the tuning accuracy can be enhanced.
[0019]
In addition, what expressed the apparatus mentioned above as a method, a system, or a program
is also within the scope of the present invention.
[0020]
According to the technique of the present invention, automatic tuning of the voice acquisition
unit of the voice recognition robot can be realized efficiently and conveniently.
[0021]
Hereinafter, embodiments of the present invention will be described with reference to the
drawings.
FIG. 1 shows a speech recognition robot 100 according to an embodiment of the present
invention.
As shown, the voice recognition robot 100 includes a head 110, a body (hereinafter referred to
as a main body), a wheel 150, and a robot arm 160. The body 120 is provided with a microphone
array 180. At the tip of the robot arm 160, a speaker 170 for outputting sound is provided.
[0022]
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The head 110 is equipped with, for example, a CCD camera that functions as the eye of the
voice recognition robot 100. The wheels 150 move the voice recognition robot 100 by rotating.
The robot arm 160 comprises a shoulder joint. The main body 120 incorporates a drive unit for
driving the robot arm 160, and the robot arm 160 can be rotated by the drive of the drive unit.
Further, the operation of these functional blocks is controlled by a control unit (not shown)
incorporated in the main body 120. Hereinafter, this control unit will be referred to as a normal
control unit in order to distinguish it from the tuning control unit described later.
[0023]
The microphone array 180 functions as the "ear" of the speech recognition robot 100, that is, as
a speech acquisition unit, and acquires speech signals.
[0024]
The main body 120 also includes a tuning unit for tuning the microphone array 180.
In the following description and illustration, reference numeral 130 is given to this tuning unit.
[0025]
FIG. 2 shows the microphone array 180 and the tuning unit 130. As illustrated, the microphone
array 180 includes a voice input unit 182 formed by arranging a plurality of (three in the
illustrated example) microphones 182a, 182b, and 182c, and a microphone array processing unit
184. The microphone array processing unit 184 is obtained by an AD converter 186 that obtains
a digital audio signal by performing analog-to-digital (AD) conversion on an audio signal input by
each microphone of the audio input unit 182, and an AD converter 186. Correction unit 188 that
respectively corrects the digital sound signal of each microphone, and a frequency conversion
unit 190 that converts the frequency by performing FFT conversion on the digital sound signal of
each microphone corrected by the correction unit 188 A voice enhancement unit 192 that
performs voice enhancement processing on the digital voice signal of each microphone whose
frequency has been converted, and noise that is obtained by performing noise estimation using
the digital voice signal of each microphone whose frequency is converted Noise estimation unit 1
from signals obtained by estimation unit 194 and speech enhancement unit 192 With obtaining
the desired audio signal by subtracting the noise signal estimated by 4, it comprises a feature
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amount obtaining unit 196 outputs the extracted feature amount for speech recognition from the
target speech signal. Note that the feature amount obtained by the feature amount obtaining unit
196 is input to a voice recognition processing unit (not shown) provided in the main body 120 of
the voice recognition robot 100, whereby voice recognition processing is performed. The result
of the speech recognition process is output to the above-described normal control unit provided
in the main body 120 of the speech recognition robot 100, and the normal control unit performs
an operation corresponding thereto to one or more corresponding functional blocks of the
speech recognition robot 100 Let me do it.
[0026]
The speech emphasizing unit 192 mainly performs DS (Delay-and-Sum) processing. Since the
voice input unit 182 includes a plurality of microphones, the timing at which the voice signal
from the sound source reaches the microphones differs among the microphones. This will be
described using the schematic diagram of FIG.
[0027]
As shown in FIG. 3, the three microphones 20a, 20b and 20c are arranged at an interval d. The
angle between the sound source 10 and each microphone is θ. In the case of the drawing, the
timing at which the voices reach the respective microphones differs by L / sound speed (L:
interval d × sin θ) in the drawing. Therefore, the voice signals acquired by the three
microphones are out of phase, and it is necessary to match the phase with them.
[0028]
In the DS processing by the voice emphasizing unit 192, the phases of the voice signals obtained
earlier are made to be the same by sequentially delaying the voice signals acquired earlier
according to the timing deviation of the voice signals obtained from the microphones of the voice
input unit 182. The respective audio signals after being added are added. Since the DS processing
by the voice emphasizing unit 192 determines the amount to delay the voice signal obtained by
each microphone based on the estimated position of the sound source, the directional noise is
removed, and the target voice is obtained. Have an emphasizing effect.
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[0029]
The noise estimation unit 194 mainly performs NBF (Null-Beam-Former) processing. This NBF
processing emphasizes signals in directions other than the direction of the target voice to form a
blind spot in the target voice direction. The noise estimation unit 194 obtains diffusive noise.
[0030]
Then, the feature amount acquiring unit 196 subtracts the noise signal acquired by the noise
estimating unit 194 from the speech signal acquired by the speech emphasizing unit 192,
thereby removing the diffusive noise to obtain the target speech.
[0031]
FIG. 4 shows an example of an ideal directivity pattern of a microphone array.
The frequency in the figure corresponds to θ in FIG. In order to obtain the target voice signal
correctly and to improve the accuracy of voice recognition, the microphone array is designed to
have this ideal directivity pattern as much as possible.
[0032]
By the way, there is always an error in the sensitivity of the microphone. It is known that
inexpensive microphones currently on the market usually have a sensitivity error of 2 decibels
(dB) or more. Therefore, even if the same microphones constitute a microphone array, variations
in sensitivity can not be avoided among the microphones.
[0033]
Variations in sensitivity among the microphones particularly affect the noise estimation process.
If the accuracy of the noise estimation process decreases, distortion occurs in the directivity
pattern of the microphone array, and the accuracy of speech recognition also decreases.
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[0034]
The correction unit 186 is for eliminating variations in sensitivity characteristics of the
microphones of the audio input unit 182, and corrects the audio signal from each of the
microphones with a correction filter set for each microphone. In addition, since the reception
characteristics of each microphone may change due to the passage of time, the change of the
environment in which the voice recognition robot 100 is placed, etc., it is necessary to tune the
microphone array 180 from time to time.
[0035]
The tuning unit 130 is for tuning the microphone array 180. At the time of tuning, audio signals
acquired by the microphones of the audio input unit 182 are input to the tuning unit 130, and
the tuning unit 130 uses them to set correction filters for the respective microphones and
supplies them to the correction unit 188.
[0036]
FIG. 5 shows the tuning unit 130. The tuning unit 130 has a tuning control unit 135 and a tuning
execution unit 140. The tuning control unit 135 performs a process of determining whether to
perform tuning on the microphone array 180 and a process of controlling the robot arm 160 and
the speaker 170 of the voice recognition robot 100 when it is determined to be "do". Do. Note
that each element described in the figure as a functional block that performs various processes of
the tuning unit 130 can be configured by a CPU, a memory, and other LSIs in terms of hardware,
and in terms of software, a memory It is realized by the program etc. which were loaded to.
Therefore, it is understood by those skilled in the art that these functional blocks can be realized
in various forms by hardware only, software only, or a combination thereof, and is not limited to
any of them.
[0037]
The determination as to whether or not to perform the tuning is performed based on whether or
not there is a possibility that the variation pattern of the sound receiving characteristic of each
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microphone of the voice input unit 182 in the microphone array 180 has changed. For example,
when predetermined time, such as 24 hours, has passed since the last tuning, when the result of
performing sound environment clustering indicates that the environmental sound has changed,
the wheel 150 is moved by the above-described normal control unit of the voice recognition
robot 100 If it is determined that there is control to be performed, it is determined that tuning is
required. Of course, the conditions for this determination are not limited to those described here.
[0038]
The tuning control unit 135 controls the operation of the robot arm 160 and the speaker 170
when it is determined that tuning is to be performed . First, control of the robot arm 160 will
be described. Control of the robot arm 160 is performed through control of a drive unit (not
shown) incorporated in the main body 120, and in the following description, is used in the same
sense as control of the robot arm 160 and control of the drive unit. The robot arm 160 is
controlled by the tuning control unit 135 at the time of tuning, and is controlled by the normal
control unit at the time of normal operation other than the tuning.
[0039]
FIG. 6 is a top view of the speech recognition robot 100. As shown in FIG. For the sake of clarity,
only the main body 120 and the robot arm 160 (including the speaker 170 attached thereto) are
illustrated, and the head 110 and the wheel 150 are omitted. The tuning control unit 135 is an
angle formed by the voice input unit 182 and the robot arm 160 in the microphone array 180
provided in the main body 120, more precisely, an angle α formed by the arrangement direction
of each microphone of the voice input unit 182 and the robot arm 160. The robot arm 160 is
rotated so as to have a predetermined value. The speaker 170 mounted on the tip of the robot
arm 160 changes its voice output direction and the direction formed by the voice input unit 182
as the robot arm 160 rotates. That is, by rotating the robot arm 160, the tuning control unit 135
sets the angle θ shown in the schematic view of FIG. 3 to a value corresponding to the
predetermined value of the angle α.
[0040]
After the robot arm 160 rotates, the tuning control unit 135 causes the speaker 170 attached to
the robot arm 160 to output a reference sound. In this embodiment, a TSP (Time-Stretched-Pulse)
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signal is used as the reference speech.
[0041]
When each microphone of the voice input unit 182 receives a TSP signal from the speaker 170,
it outputs a response signal (hereinafter referred to as a TSP response signal). These TSP
response signals are input to the tuning execution unit 140 of the tuning unit 130.
[0042]
The tuning execution unit 140 time-reverses the TSP signal to obtain a TSP time-reversal signal,
and convolutes the TSP time-reversal signal into the TSP response signal of each microphone. By
this, an impulse response signal of each microphone is obtained.
[0043]
As described above, the correction unit 188 is for eliminating variations in sensitivity of the
microphones of the voice input unit 182, and performs correction using a correction filter for
each microphone. The tuning execution unit 140 sets these correction filters so that the
sensitivities of the microphones become uniform.
[0044]
In the present embodiment, the tuning execution unit 140 sets correction filters of other
microphones so as to have the same sensitivity as that of the reference microphone in the audio
input unit 182. Specifically, the power spectrum of the microphone is calculated from the
impulse response signal of the target microphone, and the correction filter A of this microphone
is determined according to the following equation (1).
[0045]
A = P / P0 (1) where A: correction filter P: power spectrum of the target microphone P0: power
spectrum of the reference microphone It is to be noted that which one of the microphones
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included in the voice input unit 182 is used as the reference microphone It is left to the designer.
[0046]
Furthermore, in the actual use environment, the speech recognition robot 100 considers that it is
necessary to receive speech signals from sound sources in various directions, and in the present
embodiment, the tuning unit 130 determines at a plurality of different angles α. Tune.
Specifically, for one microphone, a correction filter A is obtained for each angle α, and these
correction filters A are integrated to obtain an integrated correction filter.
[0047]
The tuning execution unit 140 obtains integrated correction filters for microphones other than
the reference microphone and outputs the integrated correction filter to the correction unit 188.
The correction unit 188 updates the correction filters of these microphones to the respective
integrated correction filters output from the tuning execution unit 140.
[0048]
In addition, since it is preferable to set a correction filter for each frequency of the audio signal in
order to obtain a better correction effect, in the present embodiment, a plurality of tuning control
units 135 have different frequencies (bins) at the time of tuning. TSP signals are sequentially
output to the speaker 170. The tuning execution unit 140 obtains the correction filter A for each
frequency (bin) for each microphone other than the reference microphone and supplies the
correction filter A with the correction filter A.
[0049]
FIG. 7 is a flow chart showing the flow of processing of the tuning unit 130 in the speech
recognition robot 100 of the present embodiment. In the standby state, the tuning control unit
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135 in the tuning unit 130 determines whether to perform tuning (S10). If it is determined that
"does not execute" (S10: No), while the standby state of the tuning unit 130 continues (S20), if it
is determined as "execute" (S10: Yes), the tuning control unit 135 The robot arm 160 of the
recognition robot 100 is rotated (S30), and after rotation of the robot arm 160, the speaker 170
is caused to output a TSP signal (S40).
[0050]
The tuning executing unit 140 executes tuning (S50). Specifically, the tuning execution unit 140
obtains the correction filter A of each microphone other than the reference microphone using the
TSP response signal of each microphone to the TSP signal and the time inverted signal of the TSP
signal. Then, the tuning control unit 135 further rotates the robot arm 160 to change the angle
α, and causes the speaker 170 to output a TSP signal of the same frequency. For the changed
angle α, the tuning execution unit 140 obtains the correction filter A again for each microphone
other than the reference microphone. The change of the angle α, the output of the TSP signal,
and the calculation of the correction filter A are repeated a plurality of times, and for each
microphone, the same number of correction filters A as the number of the angles α are obtained.
The tuning execution unit 140 integrates the correction filter A for each microphone other than
the reference microphone to obtain an integrated correction filter, and outputs the integrated
correction filter to the correction unit 188.
[0051]
When the processing for obtaining the integrated correction filter for one frequency (bin) ends,
the tuning control unit 135 causes the speaker 170 to output TSP signals of different frequencies
(bin), and the tuning execution unit 140 operates on the frequency (bin). The above processing
for obtaining the integrated correction filter is performed.
[0052]
Thus, from the tuning execution unit 140 to the correction unit 188, the integrated correction
filter of the correction filter A obtained for the plurality of angles α for each frequency (bin) of
each microphone other than the reference microphone is provided.
[0053]
The voice recognition robot 100 of the present embodiment has a tuning function, and the
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speaker 170 is mounted on the robot arm 160, and can output a reference voice for tuning
according to the control of the tuning control unit 135.
Therefore, when performing tuning, there is no need to move the robot to the installation place
of the reference sound source, man-hours and cost can be suppressed in the production site, and
convenience is provided to the user in actual use.
Furthermore, there is an advantage that the installation place of the reference sound source for
tuning is not required.
[0054]
Further, in the present embodiment, the speaker 170 is attached to the robot arm 160 of the
voice recognition robot 100. In general, a robot arm is provided in a robot, and by using the
robot arm as a mounting unit of the voice output unit, the configuration of the voice recognition
robot can be simplified.
[0055]
Furthermore, since the robot arm is a displacement unit capable of displacing the audio output
unit (speaker) attached thereto relative to the microphone array, when the robot arm is rotated, it
is fixed to the audio output unit and the robot It is possible to change the relative positional
relationship with the acquired voice acquisition unit. By this, the position of the audio output unit
can be easily changed at the time of tuning so as to be a suitable relative position suitable for
tuning. Further, as in the case of the voice recognition robot 100, it is convenient when the voice
acquisition unit needs to perform tuning for each different relative position.
[0056]
Furthermore, since the reach of the robot arm is mechanically fixed normally, there is little
movement error when changing the relative position of the audio output unit and the audio
acquisition unit by rotating it. As a result, it is possible to reduce an error in the relative position
of the voice acquisition unit and the voice acquisition unit.
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[0057]
The present invention has been described above based on the embodiments. The embodiment is
an exemplification, and various changes, additions, and decreases may be made without
departing from the spirit of the present invention. Those skilled in the art will understand that
variations to which these changes, additions, and decreases are added are also within the scope
of the present invention.
[0058]
For example, in the voice recognition robot 100 according to the embodiment described above,
the speaker 170 functioning as a voice output unit is provided on only one robot arm, but the
voice output units may be provided on both robot arms.
[0059]
Further, although the speech recognition robot 100 has a speech acquisition unit which is a
microphone array, the present invention can be applied to a speech recognition robot having any
kind of speech acquisition unit that requires a reference speech at the time of tuning.
[0060]
Further, the tuning unit 130 in the voice recognition robot 100 sets the angle α as a relative
position between the speaker 170 and the voice input unit 182, and changes it at the time of
tuning.
The relative position between the voice acquisition unit and the voice input unit may include the
distance between the voice acquisition unit and the voice input unit without being limited to the
angle formed by them.
Therefore, the angle and the distance may be changed, and tuning may be performed for each
angle and for each distance, and the results may be integrated. The change of the distance may
be realized, for example, by using a robot arm that is not only rotatable but also expandable and
contractable by extending and retracting the robot arm at the time of tuning.
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[0061]
Further, in the present embodiment, a robot arm having a shoulder joint is used as an example,
but if the relative positional relationship between the sound output unit and the sound
acquisition unit attached thereto can be displaced, only the shoulder joint is Alternatively, for
example, a robot arm including one or more of a shoulder joint, an elbow joint, and an arm joint
may be used.
[0062]
It is a figure showing a speech recognition robot concerning an embodiment of the invention.
It is a figure which shows the microphone array and tuning part in the speech recognition robot
shown in FIG. It is a figure for demonstrating the process of the audio ¦ voice emphasis part in
the microphone array shown in FIG. It is a figure which shows the example of the ideal directivity
pattern of the microphone array shown in FIG. It is a figure which shows the detail of a tuning
part. It is a figure for demonstrating the tuning control part in the tuning part shown in FIG. It is
a flowchart which shows the flow of a process of the tuning part shown in FIG.
Explanation of sign
[0063]
DESCRIPTION OF SYMBOLS 10 sound source 20a microphone 20b microphone 20c microphone
100 voice recognition robot 110 head 120 main body 130 tuning unit 135 tuning control unit
140 channeling execution unit 150 wheel 160 robot arm 170 speaker 180 microphone array
182 voice input unit 184 microphone array processing unit 186 AD conversion Unit 188
Correction unit 190 Frequency conversion unit 192 Speech enhancement unit 194 Noise
estimation unit 196 Feature quantity acquisition unit
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