JP4887968B2 - Audio conferencing equipment - Google Patents

Description

  The present invention relates to an audio conference apparatus used for a conversation or a conference between remote points.

  Conventionally, an audio conference apparatus has been proposed as an apparatus used for a conference between a plurality of points (see Non-Patent Document 1).

  The audio conference apparatus described in Non-Patent Document 1 includes a microphone array and a speaker array, and is small and can be used by being placed on a table in a conference room. During a conference using such an audio conference device, a conference participant may be unconsciously hitting the desk with a finger or a pen. When a conference participant hits the desk, vibration is generated and propagates to the audio conference device, and the vibration propagates to each microphone unit of the microphone array. In general, the microphone unit detects a change in sound pressure by vibration of the diaphragm. As described above, when vibration is transmitted from the desk to the microphone unit through the apparatus main body, the vibration causes the diaphragm to vibrate. For this reason, this vibration is detected as a change in sound pressure, and an audio signal including this vibration component is sent to the audio conference device at another point and emitted from the audio conference device speaker array at the other point. Since this sound is an annoying sound that has nothing to do with the conference, it gives a sense of discomfort and discomfort to the conference participants at other points.

As a configuration for preventing the occurrence of such a problem, the above-mentioned problem can be solved by applying a conventional technique (see Patent Document 1) that removes vibration using a signal from an angular velocity sensor to the audio conference apparatus. Is possible.
YAMAHA News Release Yamaha Teleconference System “Project Phone” “PJP-100H” / “PJP-100UH”, [online], March 10, 2006, Yamaha Corporation, [Search June 12, 2006], Internet <Http://www.yamaha.co.jp/news/2006/06031002.html> JP 2002-344787 A

  In the sound collecting device described in Patent Literature 1, the component of the detection signal caused by vibration output from the angular velocity sensor is subtracted from the audio signal and canceled, and only the audio signal is recorded.

  However, since the angular velocity sensor has high sensitivity in a high frequency region and low sensitivity in a low frequency region, there is a problem that the low region of the vibration component included in the audio signal cannot be completely removed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an audio conference device that can completely eliminate vibrations propagating from the outside.

  The present invention has the following configuration as means for solving the above problems.

(1) a microphone unit provided in the apparatus body;
A displacement sensor and an acceleration sensor for detecting vibration propagating from the outside to the apparatus body and outputting a vibration detection signal;
A synthesizing unit that synthesizes a region of the vibration detection signal output from the displacement sensor with a frequency lower than a predetermined frequency and a region of the vibration detection signal output from the acceleration sensor with a frequency equal to or higher than the predetermined frequency, and outputs a combined vibration detection signal;
A computing means for outputting a subtracted audio signal obtained by subtracting the synthesized vibration detection signal from the audio signal picked up by the microphone unit;
Communication means for transmitting the subtracted audio signal output by the arithmetic means to the counterpart device;
It is provided with.

  In general, a displacement sensor or an acceleration sensor is used for vibration detection, but the sensitivity of the displacement sensor is high in a low frequency region, and the sensitivity of the acceleration sensor is high in a high frequency region. In this configuration, the vibration that is generated when the conference participant strikes the table or the like on which the audio conference apparatus is placed and propagates to the microphone unit of the apparatus main body is detected by the displacement sensor and the acceleration sensor. And the area | region below the fixed frequency of the vibration detection signal which the displacement sensor output, and the area | region more than the fixed frequency of the vibration detection signal which the acceleration sensor output are synthesize | combined. Further, the synthesized vibration detection signal is subtracted from the audio signal collected by the microphone unit. Therefore, the voice conference device can detect the vibration propagating from the outside with high sensitivity in the entire band, and by subtracting the synthesized signal synthesized by the synthesizing means from the voice signal collected by the microphone unit, It is possible to completely remove the noise sound caused by the vibration, and it is possible to prevent the conference participants around the partner apparatus from feeling uncomfortable or uncomfortable.

  (2) Characteristic correction means for correcting the synthetic vibration detection signal based on the sound collection characteristic of the microphone unit and outputting the synthetic vibration detection signal to the arithmetic means is provided.

  In this configuration, the characteristic correcting unit corrects the combined vibration detection signal combined by the combining unit based on the sound collection characteristic of the microphone unit. Therefore, since the vibration detection characteristics of the displacement sensor and the acceleration sensor can be corrected to be the same as the vibration detection characteristics of the microphone unit, the sound based on the vibration propagated from the outside can be obtained from the sound collected by the microphone unit. It can be completely removed.

(3) first vibration detection signal delay means for delaying the vibration detection signal output by the displacement sensor;
Second vibration detection signal delay means for delaying the vibration detection signal output from the acceleration sensor;
Voice signal delay means for delaying a voice signal picked up by the microphone unit.

  In the audio conference apparatus, the positions at which the microphone unit, the displacement sensor, and the acceleration sensor are provided are different from each other, and therefore the timing at which each detects vibration propagating from the outside is also different. In this configuration, since the signals output from the microphone unit, the displacement sensor, and the acceleration sensor can be individually delayed, the amount of vibration propagated to the microphone unit is included by adjusting the delay amount of each signal. By removing the vibration component from the audio signal using the vibration detection signal detected and output by the displacement sensor and the acceleration sensor, only the audio signal can be sent to the counterpart device.

  (4) The displacement detection direction of the displacement sensor and the acceleration detection direction of the acceleration sensor are arranged in the same direction as the vibration direction of the diaphragm of the microphone unit.

  In this configuration, the vibration direction of the diaphragm of the microphone unit is the same as the displacement detection direction of the displacement sensor and the acceleration sensor. Therefore, when vibration propagates from the outside to the microphone unit via the device body, the displacement sensor and acceleration sensor also vibrate in the same direction, so that vibration transmitted to the microphone unit can be reliably detected and generated by vibration. This makes it possible to remove all the annoying sounds that occur.

  (5) The displacement sensor and the acceleration sensor are hermetically installed in the apparatus main body.

  In this configuration, the displacement sensor and the acceleration sensor are installed in a sealed state in the apparatus main body. As a result, since the voice uttered by the speaker is not directly transmitted to the displacement sensor or the acceleration sensor, the displacement sensor and the acceleration sensor are not affected by the voice uttered by the speaker. And the vibration component picked up by the microphone unit can be reliably removed from the audio signal.

  The voice conference apparatus of the present invention includes a displacement sensor that can detect a low frequency region of vibration with high sensitivity and an acceleration sensor that can detect high frequency region of vibration with high sensitivity, and detects the vibration output from the displacement sensor. A composite vibration detection signal is generated by synthesizing the region below the certain frequency of the signal and the region above the certain frequency of the vibration detection signal output from the acceleration sensor, and further, the combined vibration detection based on the sound collection characteristics of the microphone unit The corrected vibration detection signal is generated by correcting the signal. Then, the corrected vibration detection signal is subtracted from the audio signal output from the microphone unit. As a result, the microphone unit not only utters the voice uttered by the speaker, but also oscillates the vibration propagating from the outside to the main body of the apparatus. it can. Therefore, even if a conference participant hits the table on which the audio conference device is struck during a conference using the audio conference device of the present invention, vibrations caused by the vibration can be completely removed. Therefore, it is possible to prevent the conference participants in the vicinity of the counterpart device from being uncomfortable or uncomfortable.

  FIG. 1 is a characteristic diagram showing the relationship between the frequency and output of the displacement sensor, speed sensor, and acceleration sensor. In general, a displacement sensor, a speed sensor, or an acceleration sensor is used to detect vibration. As shown in FIG. 1, when the output of the speed sensor is constant with respect to the frequency, the output with respect to the frequency of the displacement sensor and the acceleration sensor generally has high sensitivity of the displacement sensor in a low frequency region, In high areas, the sensitivity of the acceleration sensor is high. From this, when a low frequency region is measured with a displacement sensor and a high frequency region is measured with an acceleration sensor, vibration can be detected with high sensitivity over the entire frequency band.

  Therefore, in the audio conference apparatus according to the present invention, as described above, a displacement sensor and an acceleration sensor are provided as vibration detecting means for detecting vibration propagating from the outside to the apparatus body, and these two vibration sensors are used in combination. Thus, it is intended to obtain good vibration detection sensitivity over the entire frequency band. That is, in the vibration propagated from the outside, a signal output from the displacement sensor is used to cancel a low frequency region. In addition, in the vibration propagated from the outside, a signal output from the acceleration sensor is used to cancel a high frequency region. Thereby, the audio signal (vibration component) due to vibration can be satisfactorily canceled over the entire frequency band from the audio signal output from the microphone unit.

  Here, as the displacement sensor, an electrostatic sensor, an electromagnetic sensor (eddy current sensor), an optical sensor, or the like is suitable. Moreover, as an acceleration sensor, a sensor of a piezoelectric type, a capacitance type, a piezoresistive type or the like is suitable.

  FIG. 2 is a conceptual diagram showing an arrangement form of a displacement sensor, an acceleration sensor, and a microphone unit provided in the audio conference apparatus of the present invention. FIG. 2 shows, as an example, a case where an electromagnetic sensor (proximity sensor) is used as the displacement sensor and a piezoelectric sensor is used as the acceleration sensor. As shown in FIG. 2, in the audio conference apparatus 1, a displacement sensor 16 and an acceleration sensor 21 are installed in the vicinity of the microphone unit 11. By arranging in this way, the vibration propagating to the microphone unit 11 can be reliably detected by the displacement sensor 16 and the acceleration sensor 21.

  Further, the displacement sensor 16 and the acceleration sensor 21 are arranged in a state of being sealed by the partition wall 14 so that sound does not propagate from the outside in the apparatus main body. Thereby, the displacement sensor 16 and the acceleration sensor 21 do not vibrate due to the voice uttered by the speaker, and can reliably detect only the vibration propagating from the outside.

  Furthermore, as shown in FIG. 2, in the audio conference apparatus 1, the direction in which the diaphragm 11 </ b> S of the microphone unit 11 vibrates and the direction in which the displacement sensor 16 and the acceleration sensor 21 detect or vibrate are the same direction. It is arranged to be. Thereby, the vibration transmitted from the outside and transmitted to the diaphragm 11 </ b> S of the microphone unit 11 can be reliably detected by the displacement sensor 16 and the acceleration sensor 21.

  In addition, as shown in FIG. 2, the displacement sensor 16 is mounted in the partition wall 14 of the apparatus main body via a vibration isolation member 15. Therefore, the vibration of the apparatus main body (housing 72) can be reliably detected without causing the displacement sensor itself to vibrate due to vibration propagating from the outside.

  Next, in the audio conference apparatus of the present invention, a configuration for removing the vibration component from the audio signal output from the microphone unit will be described based on a block diagram. FIG. 3 is a block diagram showing a vibration component removing circuit for removing a vibration component from an audio signal output from the microphone unit in the audio conference apparatus according to the present invention.

  The vibration component removing circuit 10 includes a delay 12, a displacement sensor 16, a characteristic correction circuit 17, a delay 18, a low-pass filter 19, an acceleration sensor 21, a characteristic correction circuit 22, a delay 23, a high-pass filter 24, a sensitivity correction filter 26, and a subtraction process. Part 27.

  In the audio conference apparatus 1, the timing for detecting the vibration propagating from the table or the like on which the audio conference apparatus 1 is mounted differs depending on where the microphone unit 11, the displacement sensor 16, and the acceleration sensor 21 are provided in the apparatus main body. Therefore, by providing the delay 12, the delay 18, and the delay 23 in the subsequent stage of the microphone unit 11, the displacement sensor 16, and the acceleration sensor 21, respectively, the timings of the signals that are output from the microphone unit 11, the displacement sensor 16, and the acceleration sensor 21, respectively. The vibration component can be removed from the audio signal output from the microphone unit.

  Here, the signal delay amounts of the delay 12, the delay 18, and the delay 23 are set in advance.

  The microphone unit 11 picks up the voice uttered by the speaker and converts the vibration propagated from the outside to the apparatus main body into a voice signal, and therefore outputs a voice signal including a vibration component. The audio signal including the vibration component is subjected to delay processing for a predetermined time in the delay 12 and is sent to the subtraction processing unit 27.

  The displacement sensor 16 and the acceleration sensor 21 detect vibration propagated from the outside to the apparatus main body, and output a vibration detection signal corresponding to the vibration. Here, as an example, the output of the displacement sensor 16 is larger than that of the acceleration sensor 21 at 300 Hz or less, and the output of the acceleration sensor 21 is larger than that of the displacement sensor 16 at 300 Hz or more. Therefore, the low-pass filter 19 is set to cut a signal of 300 Hz or higher so that vibration is removed using the output of the displacement sensor 16 at less than 300 Hz, and vibration is removed using the output of the acceleration sensor 21 at 300 Hz or higher. The high pass filter 24 is set so as to cut a signal of less than 300 Hz.

  The vibration detection signal corresponding to the vibration detected by the displacement sensor 16 is converted into linear data in the characteristic correction circuit 17, subjected to delay processing for a predetermined time in the delay 18, sent to the low-pass filter 19, and passed through the low-pass filter. From 19, a vibration detection signal of less than 300 Hz is sent to the sensitivity correction filter 26.

  The vibration detection signal corresponding to the vibration detected by the acceleration sensor 21 is converted into linear data in the characteristic correction circuit 22, subjected to delay processing for a predetermined time in the delay 23, sent to the high-pass filter 24, and sent to the high-pass filter From 24, a vibration detection signal of 300 Hz or higher is sent to the sensitivity correction filter 26.

  The sensitivity correction filter 26 has the microphone unit 11 so that the characteristics of the vibration detection signal detected by the displacement sensor 16 and the acceleration sensor 21 and the characteristics of the audio signal including the vibration component output by the microphone unit 11 are the same. Sensitivity characteristics (frequency characteristics) are preset. Therefore, in the sensitivity correction filter 26, the vibration detection signal of less than 300 Hz output from the low pass filter 19 and the vibration detection signal of 300 Hz or more output from the high pass filter 24 are combined, and the sensitivity characteristic as described above. (Frequency characteristics) is corrected. Then, the vibration detection signal is output to the subtraction processing unit 27.

  The subtraction processing unit 27 subtracts the vibration detection signal output from the sensitivity correction filter 26 from the audio signal including the vibration component output from the microphone unit 11 and subjected to delay processing by the delay 12. The subtraction processing unit 27 includes an amplifier (not shown), and performs subtraction processing after aligning the signal levels of the audio signal including the vibration component and the vibration detection signal. Then, the subtraction processing unit 27 outputs an audio signal from which the vibration component is removed.

  With such a configuration, the vibration propagated to the microphone unit 11 can be completely removed using the vibration detection signal detected by the displacement sensor 16 and the acceleration sensor 21.

  Next, an audio conference apparatus to which the vibration component removal circuit described with reference to FIG. 3 is applied will be described. FIG. 4 is an external view of the audio conference apparatus. FIG. 5 is a functional block diagram of the audio conference apparatus. FIG. 6 is a diagram illustrating a configuration of an audio conference apparatus during an audio conference.

  As shown in FIG. 4, the audio conference apparatuses 61 and 62 include a microphone array MA1 including microphone units MIC101 to MIC116 on the front side 72M of the casing 72, and microphone units MIC201 to MIC216 on the rear side 72U of the casing 72. The microphone array MA2 is provided. In addition, a speaker array SA1 including speaker units SP301 to SP312 is provided on the lower surface 72K of the casing 72.

  As shown in FIG. 5, the audio conference apparatuses 61 and 62 include an operation unit 74, a display unit 77, a control unit 110, an input / output connector 81, an input / output I / F (interface) 112, a sound emission directivity control unit 113, D / A converter 114 (114-1 to 114-12), sound emission amplifier 115 (115-1 to 115-12), speaker units SP301 to SP312 constituting speaker array SA1, and microphone arrays MA1 and MA2 are constituted. Microphone units MIC101 to MIC116 and microphone units MIC201 to MIC216, sound collecting amplifier 116 (116-1 to 116-32), A / D converter 117 (117-1 to 117-32), sound collecting beam generating unit 118, sound collecting A sound beam selection unit 119 and an echo cancellation unit 120 are provided.

  Further, as shown in FIG. 1, the audio conference apparatuses 61 and 62 include the vibration component removing circuit 10 therein, and as shown in FIG. 1, the displacement sensor 16 and the acceleration sensor 21 are The voice conference apparatuses 61 and 62 are hermetically sealed so as not to pick up the voice propagating from the outside.

  The control unit 110 of the audio conference apparatuses 61 and 62 converts the audio signal from the partner apparatus input from the input / output I / F 112 from a network format data to a general audio signal, and passes through the echo cancellation unit 120. While outputting to the sound emission directivity control part 113, the azimuth | direction data attached to the input audio | voice signal is acquired, and sound emission control with respect to the sound emission directivity control part 113 is performed.

  The sound emission directivity control unit 113 generates sound emission sound signals for the speaker units SP301 to SP312 according to the sound emission control contents. The sound output sound signal for the speaker units SP301 to SP312 is formed by performing signal control processing such as delay control and amplitude control on the input sound signal. The D / A converter 114 (114-1 to 114-12) converts the sound output sound signal in a digital format into an analog format, and the sound output amplifier 115 (115-1 to 115-12) amplifies the sound output sound signal. The speaker units SP301 to SP312 convert the sound emission sound signal into sound and emit the sound. Thereby, the voice of the conference person of the other party apparatus connected with the network is emitted to the conference person of the own apparatus.

  The microphone units MIC101 to MIC116 and the microphone units MIC201 to MIC216 collect ambient sounds including the utterances of the conference participants of their own devices and convert them into electrical signals, and generate collected audio signals.

  The sound collection beam generation unit 118 includes the vibration component removal circuit 10 described with reference to FIG. 3, and each microphone unit uses the vibration detection signals detected by the displacement sensor 16 and the acceleration sensor 21 as described above. The vibration components included in the audio signals picked up by the MICs 101 to MIC 116 and the microphone units MIC 201 to MIC 216 are removed. In addition, the sound collection beam generation unit 118 performs delay processing on the sound collection signals of the microphone units MIC101 to MIC116 and the microphone units MIC201 to MIC216, and the sound collection beam sound signals MB1 to MB8 having strong directivity in a predetermined direction. Is generated. The collected sound beam audio signals MB1 to MB8 are set so as to have strong directivity in different directions.

  As shown in FIG. 6, in the audio conference apparatus 61, MB1 is set to the direction Dir11, MB2 is set to the direction Dir12, MB3 is set to the direction Dir13, MB4 is set to the direction Dir14, MB5 is set to the direction Dir15, MB6 is set to the direction Dir16, and MB7 is set. In the direction Dir17, MB8 is set in the direction Dir18. As shown in FIG. 6, in the audio conference apparatus 62, MB1 is set to the direction Dir21, MB2 is set to the direction Dir22, MB3 is set to the direction Dir23, MB4 is set to the direction Dir24, MB5 is set to the direction Dir25, MB6 is set to the direction Dir26, MB7 is set in the direction Dir27, and MB8 is set in the direction Dir28.

  The collected sound beam selecting unit 119 compares the signal strengths of the collected sound beam sound signals MB1 to MB8, selects the collected sound beam sound signal having the highest intensity, and outputs it to the echo canceling unit 120 as the collected sound beam sound signal MB. To do. The sound collection beam selection unit 119 detects the direction Dir corresponding to the selected sound collection beam sound signal MB and supplies the detected direction to the control unit 110. The input / output I / F 112 converts the collected sound beam audio signal MB from the echo cancel unit 120 into an audio signal having a predetermined data length in a network format, and attaches the azimuth data and the collected sound time data obtained from the control unit 110. And output to the network 5.

  In this way, in the configuration shown in FIG. 6, the audio conference device 61 (62) removes the vibration component from the audio signal including the vibration component picked up by the microphone array MA1 or the microphone array MA2, and only the audio signal is audio conference. The data is transmitted to the device 62 (61) via the network 5. When receiving the audio signal, the audio conference device 62 (61) emits beamed audio from the speaker array SA1 to each speaker.

  Next, a second embodiment of the present invention will be described. FIG. 7 is a conceptual diagram showing an arrangement form of the first microphone unit and the second microphone unit provided in the audio conference apparatus according to the second embodiment of the present invention. FIG. 8 is a block diagram showing a vibration component removal circuit in the audio conference apparatus according to the second embodiment of the present invention.

  In the audio conference apparatus 2 according to the second embodiment of the present invention, the microphone unit 51 having the same sound collection characteristics as the microphone unit 11 that collects the voice of the speaker is used instead of the displacement sensor 16 and the acceleration sensor 21. Thus, similarly to the audio conference apparatus 1, even if vibration is propagated from the outside to the apparatus main body, it is possible to output an audio signal obtained by removing the vibration component from the audio signal.

  As shown in FIG. 7, in the audio conference apparatus 2, a microphone unit 51 is installed in the vicinity of the microphone unit 11. Thereby, the vibration propagating to the microphone unit 11 can be reliably detected by the microphone unit 51.

  The microphone unit 51 is arranged in a state of being sealed by a partition wall 54 so that sound does not propagate from the outside in the apparatus main body. Further, the inside of the partition wall is filled with a sound absorbing material 55, and the periphery of the microphone unit 51 is covered with the sound absorbing material 55. Thereby, the microphone unit 51 does not directly pick up the voice uttered by the speaker, and can reliably detect only the vibration propagating from the outside.

  Furthermore, in the audio conference apparatus 2, the direction in which the diaphragm 11S of the microphone unit 11 vibrates and the direction in which the diaphragm 51S of the microphone unit 51 vibrates are arranged in the same direction. Thereby, the vibration transmitted from the outside and transmitted to the diaphragm 11 </ b> S of the microphone unit 11 can be reliably detected by the microphone unit 51.

  Next, in the audio conference apparatus of the present invention, a configuration for removing the vibration component from the audio signal output from the microphone unit will be described based on a block diagram. FIG. 8 is a block diagram showing a vibration component removing circuit that removes a vibration component from the audio signal output from the microphone unit in the audio conference apparatus according to the present invention.

  The vibration component removal circuit 50 includes a delay 12, a microphone unit 51, a delay 52, and a subtraction processing unit 57.

  In the audio conference apparatus 1, the timing for detecting vibration propagating from a table or the like on which the audio conference apparatus 2 is mounted differs depending on where the microphone unit 51 is provided in the apparatus main body with respect to the microphone unit 11. Therefore, by providing the delay 12 and the delay 52 respectively after the microphone unit 11 and the microphone unit 51, the timing of the signal output from the microphone unit 11 and the microphone unit 51 is adjusted, and the audio signal output by the microphone unit 11 is output. Therefore, the vibration component can be removed.

  Here, it is assumed that the signal delay amounts of the delay 12 and the delay 52 are set in advance.

  The microphone unit 11 picks up the voice uttered by the speaker and converts the vibration propagated from the outside to the apparatus main body into a voice signal, and therefore outputs a voice signal including a vibration component. The audio signal including the vibration component is subjected to delay processing for a predetermined time in the delay 12 and sent to the subtraction processing unit 57.

  The microphone unit 51 detects a vibration propagated from the outside to the apparatus main body, and outputs a vibration detection signal corresponding to the vibration. The microphone unit 51 has the same sound collection characteristics as the microphone unit 11, and the vibration propagated from the outside to the apparatus main body is output as an audio signal including a vibration component, like the microphone unit 11.

  The audio signal including the vibration component output from the microphone unit 51 is subjected to delay processing for a predetermined time in the delay 52 and sent to the subtraction processing unit 57.

  The subtraction processing unit 57 subtracts the audio signal including only the vibration component output from the microphone unit 51 and delayed by the delay 52 from the audio signal including the vibration component output from the microphone unit 11 and delayed by the delay 12. An audio signal from which vibration components are removed is output.

  With such a configuration, the vibration propagated to the microphone unit 11 can be completely removed using an audio signal including only the vibration component output from the microphone unit 51.

  Also, in the audio conference apparatuses 61 and 62 shown in FIGS. 4 and 5, by providing the vibration component removal circuit 50 in the collected sound beam generation unit 118, the operation can be performed in the same manner as when the vibration component removal circuit 10 is provided. it can.

  As described above, the audio conference apparatus according to the present invention transmits vibration from the outside to the apparatus body and is transmitted to the microphone unit, and even if this vibration is converted into an audio signal, the displacement sensor and the acceleration sensor, or the second microphone unit. Since this vibration component can be reliably removed by detecting with high sensitivity, only the audio signal can be sent to the counterpart device.

It is a characteristic view which shows the relationship between the frequency and output of a displacement sensor, a speed sensor, and an acceleration sensor. It is a conceptual diagram which shows the arrangement | positioning form of the displacement sensor provided in the audio conference apparatus of this invention, an acceleration sensor, and a microphone unit. It is a block diagram which shows the vibration component removal circuit which removes a vibration component from the audio | voice signal which the microphone unit output in the audio conference apparatus of this invention. It is an external view of an audio conference apparatus. It is a functional block diagram of an audio conference apparatus. It is a figure which shows the structure of the audio conference apparatus at the time of an audio conference. It is a conceptual diagram which shows the arrangement | positioning form of the 1st microphone unit and 2nd microphone unit which are provided in the audio conference apparatus which concerns on 2nd Embodiment of this invention. It is a block diagram which shows the vibration component removal circuit in the audio conference apparatus based on 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,2- Voice conference apparatus 5-Network 10, 50- Vibration component removal circuit 11, 51- Microphone unit 12, 17, 22, 52- Delay 14, 54- Bulkhead 15- Anti-vibration member 16- Displacement sensor 18- Low pass Filter 21-Acceleration sensor 23-High pass filter 26-Sensitivity correction filter 27, 57-Subtraction processing unit 61, 62-Audio conferencing device

Claims (5)

A microphone unit provided in the apparatus body;
A displacement sensor and an acceleration sensor for detecting vibration propagating from the outside to the apparatus body and outputting a vibration detection signal;
A synthesizing unit that synthesizes a region of the vibration detection signal output from the displacement sensor with a frequency lower than a predetermined frequency and a region of the vibration detection signal output from the acceleration sensor with a frequency equal to or higher than the predetermined frequency, and outputs a combined vibration detection signal;
A computing means for outputting a subtracted audio signal obtained by subtracting the synthesized vibration detection signal from the audio signal picked up by the microphone unit;
Communication means for transmitting the subtracted audio signal output by the arithmetic means to the counterpart device;
An audio conference device.   The audio conference apparatus according to claim 1, further comprising a characteristic correcting unit that corrects the synthetic vibration detection signal based on a sound collection characteristic of the microphone unit and outputs the synthetic vibration detection signal to the arithmetic unit. First vibration detection signal delay means for delaying the vibration detection signal output by the displacement sensor;
Second vibration detection signal delay means for delaying the vibration detection signal output from the acceleration sensor;
The audio conference apparatus according to claim 1, further comprising: audio signal delay means for delaying an audio signal picked up by the microphone unit.   The audio conference apparatus according to claim 1, wherein a displacement detection direction of the displacement sensor and an acceleration detection direction of the acceleration sensor are arranged in the same direction as a vibration direction of a diaphragm of the microphone unit.   The audio conference apparatus according to claim 1, wherein the displacement sensor and the acceleration sensor are hermetically installed in the apparatus main body.

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