Meeting support system

Abstract

To provide an indication as to how to amplify and reproduce in a conference support system to properly communicate to speakers and conference participants.SOLUTION: A conference support system 1 for collecting voices of conference participants, reproducing the collected voices with speakers, and emitting the voices to the conference participants, thereby supporting the conference, includes a microphone 30 for converting input audio signals into electric signals, a filter (high-pass filter 42) for passing only electric signals corresponding to components of a predetermined frequency or higher out of the electric signals converted by the microphone 30, an amplifier 50 for amplifying the electrical signals passing through the filter (high-pass filter 42), a speaker 60 for reproducing the electrical signals amplified by the amplifier 50, and a paraboloid which is formed at a part of the ceiling and reflects voices reproduced by the speaker 60.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a conference support system that prevents a conversation in a meeting space or the like from being heard by other nearby workers, resulting in a decrease in the productivity of the other workers. [Background technology]

[0002] In recent workplaces, spaces for holding meetings and other such purposes (meeting spaces) are often located close to spaces where individuals work (work spaces).

[0003] In addition, in order to encourage collaboration, the establishment of open work spaces and the introduction of free addresses are being promoted, which are more likely to lead to accidental approach and conversation between workers. Here, an open work space is a large desk that can seat several people, and is a space that each worker can use freely to carry out their work or duties.

[0004] For example, Patent Document 1 (JP Patent Publication No. 2010-4962) discloses a furniture system that is mainly composed of large free-address desks that can be used by multiple workers facing each other.

[0005] Additionally, workplaces are often planned with a mix of different spaces to make it easier to transition from individual work to conversations and meetings.

[0006] However, in workplaces where a variety of such spaces are mixed together, there is an issue that conversations in meeting spaces or open work spaces can be heard by other workers nearby, reducing their productivity.

[0007] Therefore, the inventor proposed a conference support system in the application of Patent Document 2 (Patent Application No. 2020-86764) that collects the speech of conference participants, plays the collected speech on a speaker, and presents it to the conference participants to support the conference, in which a parabolic surface is provided on a part of the ceiling, and the sound played on the speaker is reflected by the parabolic surface. In addition, in the application, since there is a loop such as microphone → amplifier → speaker (→ parabolic ceiling surface) → microphone, and howling suppression measures are necessary, a method for suppressing howling by an electroacoustic device was proposed in the second embodiment of the application. [Patent Document 1] JP 2010-4962 A [Patent Document 2] Patent application No. 2020-86764 Summary of the Invention [Problem to be solved by the invention]

[0008] However, the above application had the problem that it did not specifically specify the frequency characteristics of the speakers and other devices used to play back audio, and did not describe how audio recorded by a microphone should be amplified and played back to be transmitted to the speaker and conference participants.

[0009] In addition, although the application proposed measures to suppress feedback, at present, even if feedback is suppressed using the above-mentioned electroacoustic device, the effect is insufficient, and the amplification rate of the sound reproduced from the speaker cannot be increased, resulting in an insufficient volume of the conversation sound transmitted to the speaker and conference participants. [Means for solving the problem]

[0010] The present invention solves the above-mentioned problems, and provides a conference support system that supports a conference by collecting voices of conference participants, reproducing the collected voices through a speaker and outputting them to the conference participants, the conference support system comprising: a microphone that converts an input voice signal into an electrical signal; a filter that passes only an electrical signal corresponding to a component of a predetermined frequency or higher out of the electrical signals converted by the microphone; an amplifier that amplifies the electrical signal that has passed through the filter; a speaker that reproduces the electrical signal amplified by the amplifier; and a parabolic surface formed on a part of a ceiling that reflects the sound reproduced by the speaker. The predetermined frequency of the component corresponding to the electrical signal to be passed by the filter is 1 kHz or more, and a sound insulating plate is provided that is flush with a horizontal plane including the top end of a structure including a housing of the speaker. It is characterized by:

[0011] A conference support system according to the present invention collects voices of conference participants, reproduces the collected voices by a speaker, and outputs the collected voices to the conference participants to support the conference. The conference support system includes a microphone that converts an input voice signal into an electrical signal, an amplifier that amplifies the electrical signal converted by the microphone, a tweeter that reproduces only an electrical signal corresponding to a component of a predetermined frequency or higher from the electrical signal amplified by the amplifier, and a parabolic surface formed on a part of a ceiling that reflects the sound reproduced by the tweeter. The predetermined frequency of the component corresponding to the electrical signal reproduced by the tweeter is 1 kHz or more, and a sound insulating plate is provided that is flush with a horizontal plane including the top end of a structure including the housing of the speaker. It is characterized by:

[0012] A conference support system according to the present invention collects voices of conference participants, reproduces the collected voices by a speaker, and outputs the collected voices to the conference participants to support the conference. The conference support system includes a microphone that converts an input voice signal into an electrical signal, a filter that passes only an electrical signal that corresponds to a component having a predetermined frequency or higher out of the electrical signals converted by the microphone, an amplifier that amplifies the electrical signal that has passed through the filter, a tweeter that reproduces only an electrical signal that corresponds to a component having a predetermined frequency or higher out of the electrical signals amplified by the amplifier, and a parabolic surface formed on a part of a ceiling that reflects the sound reproduced by the tweeter. The predetermined frequency of the component corresponding to the electric signal to be passed by the filter is 1 kHz or more, the predetermined frequency of the component corresponding to the electric signal to be reproduced by the tweeter is 1 kHz or more, and a sound insulating plate is disposed flush with a horizontal plane including the top end of a structure including a housing of the speaker. It is characterized by: Effect of the Invention

[0016] The conference support system of the present invention has a filter that passes only electrical signals corresponding to components of a predetermined frequency or higher out of the electrical signals converted by the microphone. Therefore, with this conference support system of the present invention, it is possible to provide guidelines on how to amplify and play back the audio recorded by the microphone so that it can be properly transmitted to the speaker and conference participants.

[0017] In addition, according to the conference support system of the present invention, it is possible to increase the amplification rate of the audio reproduced from the speaker by using the above-mentioned filter, thereby sufficiently increasing the volume of the conversation voice transmitted to the speaker and conference participants.

[0018] In addition, the conference support system of the present invention has a tweeter that reproduces only the electrical signal corresponding to components of a predetermined frequency or higher from the electrical signal amplified by the amplifier. Therefore, with this conference support system of the present invention, it is possible to provide guidelines on how to amplify and reproduce the audio recorded by the microphone so that it can be appropriately transmitted to the speaker and conference participants.

[0019] In addition, according to the conference support system of the present invention, it is possible to increase the amplification rate of the sound reproduced from the tweeter as described above, thereby sufficiently increasing the volume of the conversation sound transmitted to the speaker and conference participants. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 is a diagram illustrating an overview of a conference support system 1 according to an embodiment of the present invention. [Diagram 2] 2 is a block diagram of a voice processing unit 40 of the conference support system 1 according to the embodiment of the present invention. [Diagram 3] 2 is a diagram illustrating the geometric arrangement of a speaker 60 and a ceiling in the conference support system 1. FIG. [Figure 4] 1 is a diagram illustrating reflected sound from a parabolic ceiling portion 17 of the conference support system 1. FIG. [Diagram 5] FIG. 1 is a block diagram of a conference support system 1 according to a second embodiment of the present invention. [Figure 6] FIG. 11 is a block diagram of a conference support system 1 according to a third embodiment of the present invention. [Figure 7] FIG. 11 is a block diagram of a voice processing unit 40 of the conference support system 1 according to a fourth embodiment of the present invention. [Figure 8] FIG. 11 is a diagram illustrating an overview of a conference support system 1 according to a fifth embodiment of the present invention. [Figure 9] 1 is a diagram for explaining a case where a reflecting object R is placed within a sound emission range. [Figure 10] FIG. 13 is a diagram illustrating an overview of a conference support system 1 according to a sixth embodiment of the present invention. [Figure 11] 13 is a diagram for explaining the difference in propagation path based on the height of the focal point F and the height of the sound insulating plate 70. FIG. [Figure 12] 1 is a schematic diagram of sound propagation paths when the upper surface of a sound-proofing plate 70 is flat and parallel to a floor surface 20. FIG. [Figure 13] FIG. 1 is a diagram illustrating a problem caused by a small speaker 60 aligned at a focal point F. [Figure 14] 13A to 13C are diagrams illustrating effects of the conference support system 1 according to the sixth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. A meeting support system 1 according to the present invention is assumed to be applied to, for example, a meeting space provided near a large desk in a free address style where work is carried out, or an open office space.

[0022] In addition, it is expected that workers will work at the large desks in the free address style and in the open office space, while meetings will take place in the meeting space and participants will be able to speak.

[0023] In this specification, an "office worker" is defined as a person who performs desk work such as paperwork and computer input work and who does not generally use audio, and is distinguished from a conference participant who takes part in a conference in the meeting space and speaks.

[0024] The conference support system 1 according to the present invention aims to output appropriate audio to the conference participants while preventing the content of the conversation between the participants in the meeting space from being heard as much as possible by other workers at nearby large desks or in the open office space. To achieve this, the conference support system 1 according to the present invention collects the audio of the conference participants (the speakers), plays the collected audio through a speaker, and outputs it to the conference participants to support the conference.

[0025] Speech is composed of vowels and consonants, the former mainly consisting of low frequency components and the latter of high frequency components. It is known that in the hearing sense, low frequency components mask high frequency components, and this masking also works when perceiving speech. Such masking is one of the causes of poor speech audibility.

[0026] In the conference support system 1 of the present invention, when the collected voice of a speaker is played back through a speaker for the conference participants, attention is paid to the characteristics of the voice and hearing, and the frequency of the voice played back from the speaker is specified, thereby suppressing a decrease in clarity of the played back sound and solving the problem.

[0027] 1 is a diagram for explaining an overview of a conference support system 1 according to an embodiment of the present invention. The diagram shows a situation in which a conference is being held between two participants at a desk 25 placed on a floor surface 20. It is assumed that workers are working near this desk 25 at the aforementioned large free address type desk or in an open office space (neither of which are shown in the figure).

[0028] A microphone 30 is installed on the desk 25, and collects the voices of the conference participants by this microphone 30. When an audio signal is input to the microphone 30, the microphone 30 converts the audio signal into an electrical signal.

[0029] The electrical signal converted by the microphone 30 is input to the audio processing unit 40. In this audio processing unit 40, the electrical signal is converted into an appropriate signal for reproduction by the speaker 60. FIG. 2 is a block diagram of the audio processing unit 40 of the conference support system 1 according to an embodiment of the present invention. The audio processing unit 40 in FIG. 2 is one example, and various other aspects are possible. In the audio processing unit 40 in FIG. 2, the level of the electrical signal is adjusted by a volume adjustment unit 41, and the electrical signal is amplified by an amplifier 50.

[0030] 2, the electrical signal converted by the microphone 30 is input to a high-pass filter 42 in the audio processing unit 40. This high-pass filter 42 is a filter that passes only electrical signals corresponding to components of a predetermined frequency or higher out of the electrical signals output from the microphone 30. The predetermined frequency of the components corresponding to the electrical signals passed by the high-pass filter 42 is preferably 1 kHz.

[0031] Most syllables in Japanese are composed of consonants and vowels, each of which has a different frequency characteristic. In Japanese conversation, consonants are said to play an important role in transmitting speech clearly. In this embodiment, the low-frequency components that compose vowels are cut by the high-pass filter 42, and consonants that are composed of high-frequency components are emphasized, thereby improving the audibility of speech.

[0032] In the present invention, of the conversational voice recorded by the microphone 30, basically, components of 1 kHz or more (reproduction frequency band) are amplified and reproduced from a speaker 60 installed at the focus of the parabolic ceiling portion 17.

[0033] That is, in the present invention, by providing a system that amplifies and reproduces the above-mentioned reproduction frequency band, sound is reproduced by emphasizing only the frequency band that contains many consonant components.

[0034] Consonants have components mainly in a high frequency band (1 kHz to 6 kHz) compared to vowels, and the frequency band containing the main components of consonants is set to 1 kHz to 6 kHz. Therefore, in the conference support system 1 according to the present invention, the playback frequency band may be set to 1 kHz or more and 6 kHz or less. In this case, instead of the high-pass filter 42, a band-pass filter with a pass band of 1 kHz to 6 kHz may be used.

[0035] However, in the conference support system 1 according to the present invention, the playback frequency band is basically 1 kHz or more, and more preferably includes a band of 6 kHz or more. This is because, although the consonant components are weaker than the band of 1 kHz to 6 kHz, the frequency band of 6 kHz or more also includes consonant components. Also, even if the energy of consonants is minute, they affect the clarity of conversation, so it is more preferable to include 6 kHz or more in the playback frequency band, even if it does not include the main components.

[0036] The output from the high-pass filter 42 is input to the volume adjustment unit 41. The volume adjustment unit 41 adjusts the volume of the sound reproduced by the speaker 60. This volume adjustment unit 41 may be configured to operate automatically or manually. In the latter case, it is preferable that an input knob, an input slider, and other components for adjusting the volume are appropriately provided on the desk 25.

[0037] The electrical signal amplified by the amplifier 50 of the sound processing unit 40 is input to the speaker 60, and sound is reproduced by the speaker 60. The speaker 60 is installed so that its directivity faces upward, and sound is emitted from the speaker 60 towards the ceiling 10.

[0038] The ceiling 10 has a general ceiling portion 15 having a horizontal surface, and a parabolic ceiling portion 17 having a concave parabolic surface formed in a part of the general ceiling portion 15. The conference support system 1 according to the present invention is laid out so that the parabolic ceiling portion 17 is disposed above the desk 25. Moreover, it is preferable that the area of ​​the parabolic ceiling portion 17 is large enough to include at least the conference participants seated around the desk 25 in a plan view.

[0039] In this embodiment, the parabolic ceiling portion 17 is provided as part of the ceiling 10, but a structure equivalent to the parabolic ceiling portion 17 may be provided separately from the ceiling 10. For example, a parasol-like structure equivalent to the parabolic ceiling portion 17, independent of the general ceiling portion 15 in the ceiling 10, may be provided on the ceiling 10.

[0040] The parabolic ceiling portion 17 as described above reflects the sound reproduced by the speaker 60 vertically downward. In the conference support system 1 according to the present invention, the ceiling structure is devised so that sound is emitted to a limited range (a meeting space where desks 25 are arranged) even when a general speaker is used. Figure 3 is a diagram explaining the geometric arrangement of the speaker 60 and the ceiling in the conference support system 1, and is a schematic diagram showing a cross section of the ceiling 10 and floor surface 20 of a building.

[0041] The ceiling 10 is composed of a general ceiling portion 15 that is parallel to a general floor surface 20, and a parabolic ceiling portion 17 that is formed on a part of the ceiling 10. Here, the x-axis is the horizontal direction, the y-axis is the vertical direction, and coordinates (x, y) are defined with the position F of the speaker 60 (not shown in FIG. 3) as the origin.

[0042] In the coordinate system defined above, the parabolic ceiling portion 17 is defined as y=-x 2 4L+L around the y-axis. In this case, the origin (0,0) of the xy coordinate system coincides with the focal point of the paraboloid ceiling portion 17.

[0043] Furthermore, if the directivity range of speaker 60 (not shown in FIG. 1) is φ, then it is preferable that the cone defined by φ is contained within parabolic ceiling portion 17.

[0044] The sound reproduction means in the conference support system 1 according to the present invention is composed of the parabolic ceiling portion 17 having a shape forming a part of a paraboloid as described above, and a speaker 60 installed with its direction facing upward below the parabolic ceiling portion 17. The speaker 60 is installed so as to be located at the focal point F of the paraboloid of the ceiling 10.

[0045] In the above-mentioned relationship, when speaker 60 is placed at F, as shown in FIG. 4, sound reflected by parabolic ceiling portion 17 travels vertically downward toward floor surface 20.

[0046] In the conference support system 1 according to the present invention, it is preferable that the range in which the ceiling surface forms a paraboloid is the range in which the sound radiated from the speaker 60 is incident, that is, the range that can cover the directivity range of the speaker 60.

[0047] Sound emitted from speaker 60 installed at focus F of the paraboloid that constitutes parabolic ceiling portion 17 enters parabolic ceiling portion 17, which forms part of the paraboloid, and then reflects vertically downward toward desks 25 around which the conference participants are seated. In conference support system 1 according to the present invention, the sound emitted from the speaker can be kept within the desired range without using an expensive speaker system such as a parametric speaker or flat panel speaker. In this way, conference support system 1 according to the present invention can be realized at low cost using general speakers.

[0048] The inventors have already proposed the mechanism for supporting voice transmission using the parabolic ceiling portion 17 and the speaker 60 in Japanese Patent Application No. 2017-160105 (see Japanese Patent Application Laid-Open No. 2019-39166). This proposal had the effect of providing sound information such as background music and announcements to only a limited area in art galleries, museums, etc.

[0049] On the other hand, in the conference support system 1 according to the present invention, it can be considered that conference participants can objectively judge their own voice volume by listening to their own voice reproduced by the speaker 60 and reflected by the parabolic ceiling portion 17. Therefore, the conference participants can control and suppress their own voice volume by themselves. This makes it possible for the conference support system 1 to suppress conversations at a volume that can be heard by workers nearby the meeting space. Such an effect is not necessarily easily derived from the previous proposal.

[0050] Now, if the parabolic ceiling portion 17 is wider than the main directivity range of the speaker 60, the reproduced sound from the speaker 60 will not propagate to the surroundings, but will be emitted only directly below the parabolic ceiling portion 17.

[0051] In this way, by appropriately setting the directional range of the parabolic ceiling portion 17 and the speaker 60 to cover the meeting space, the sound recorded by the microphone 30 is reliably transmitted only to the conference participants who are conversing in the meeting space.

[0052] A feature of the voice transmission support by the conference support system 1 according to the present invention is that the speaker's own conversation voice is amplified and transmitted not only to the conversation partner but also to the speaker himself at the same time.

[0053] By using the conference support system 1 according to the present invention, the speaker can feel that his / her voice is heard loudly and that the person he / she is speaking with can be sure that his / her voice is being heard, so it is expected that the speaker will naturally adjust the volume of his / her voice to be lower. In this way, if the speaker's volume is lowered, the conversation sound propagating from the meeting space to the surrounding area is reduced, and the decrease in the work efficiency of other nearby workers and the degree of interference with other conversations can be reduced.

[0054] In this way, it is possible to guide the speaker to reduce the volume of their conversation while reliably transmitting sound to the conference participants who are conversing only in the meeting space covered by the parabolic ceiling section 17. As a result, it is possible to reduce the decrease in the work efficiency of other nearby workers and the degree of interference with other conversations.

[0055] The microphone 30 used in the conference support system 1 according to the present invention is preferably installed on the desk 25. However, it is also possible to use a lapel microphone worn by each of the conference participants who will be having a conversation.

[0056] According to the conference support system 1 of the present invention configured as described above, it is possible to prevent a decrease in the productivity of other workers due to conversations in a meeting space being heard by other workers nearby, without taking measures such as surrounding the meeting space with a partition.

[0057] Furthermore, the conference support system 1 of the present invention has a high-pass filter 42 that passes only the electrical signal converted by the microphone 30 that corresponds to components of a predetermined frequency or higher. Therefore, with the conference support system 1 of the present invention, it is possible to provide an indication of how to amplify and play back the audio recorded by the microphone 30 so that it can be appropriately transmitted to the speaker and conference participants.

[0058] Furthermore, according to the conference support system 1 of the present invention, by providing the high-pass filter 42 as described above, it becomes possible to increase the amplification rate of the sound reproduced from the speaker 60, and the volume of the conversation sound transmitted to the speaker and conference participants can be sufficiently increased.

[0059] Conversely, because the reproduction based on the reproduction frequency band makes the conversation voice clear, the effect of being able to transmit the voice appropriately to the conference participants can be obtained without increasing the amplification factor of the reproduced voice. In other words, even with an amplification factor that does not cause howling, the voice can be transmitted appropriately to the conference participants.

[0060] In addition, according to the conference support system 1 of the present invention, when the howling frequency is outside the playback frequency band, it is possible to sufficiently increase the amplification factor, which can also improve the audio transmissibility to the conference participants.

[0061] In addition, according to the conference support system 1 of the present invention, it is possible to reliably transmit sound only to conference participants within the range covered by the parabolic surface on the ceiling, while guiding speakers to reduce their speaking volume.

[0062] This makes it possible to reduce the amount of conversation sound propagating to adjacent spaces, which in turn reduces the degree of decline in the work efficiency of other workers in adjacent spaces, reduces the degree of interference with other conversations taking place in adjacent spaces, and reduces the feeling of noise in the entire workplace.

[0063] Furthermore, according to the conference support system 1 of the present invention, when a highly confidential conversation is held in a meeting space, it is possible to prevent the contents of the conversation from being leaked to those around.

[0064] In addition, in the conference support system 1 according to the present invention, if a microphone installed on a desk is used, a wearable device such as an intercom is not required, and the above-mentioned effects can be obtained without compromising convenience. Wearing an intercom or the like not only reduces convenience, but also can lead to a decrease in meeting efficiency due to discomfort for workers who are not accustomed to it.

[0065] In addition, in the conference support system 1 according to the present invention, a general speaker can be used as the speaker installed at the focal point, and the above-mentioned effects can be realized at low cost. Parametric speakers and flat panel speakers exist as speaker systems with narrow directional characteristics for playing back conversation sounds in a limited range, but they have problems with cost and sound quality.

[0066] Furthermore, the conference support system 1 according to the present invention is effective not only when actually having a face-to-face conversation, but also when having a conversation with a remote party in a Web conference or the like.

[0067] Next, another embodiment of the present invention will be described. In the previous embodiment, the high-pass filter 42 passes only the electric signal corresponding to the component of a predetermined frequency or more among the electric signals output from the microphone 30, and reproduces it from the speaker 60. On the other hand, in the second embodiment, such a filter is not used, and the speaker 60 is replaced with a tweeter 67 to reproduce the component of the predetermined frequency or more. The other configurations are the same as those of the first embodiment. FIG. 5 is a block diagram of the conference support system 1 according to the second embodiment of the present invention. As in the previous embodiment, in the second embodiment, the sound reproduced by the tweeter 67 is configured to be reflected by a parabolic ceiling portion 17 formed on a part of the ceiling.

[0068] In this specification, the tweeter 67 is defined as a speaker that reproduces sound components of 1 kHz or more and does not reproduce sound components of less than 1 kHz. In other words, the frequency of the sound components corresponding to the electrical signal reproduced by the tweeter 67 in Fig. 5 is 1 kHz or more, and electrical signals corresponding to sounds of lower frequencies are not reproduced.

[0069] In the conference support system 1 according to the second embodiment, the conversation voice recorded by the microphone 30 has its level of the electric signal adjusted by the volume adjustment unit 41, and the electric signal is amplified by the amplifier 50. Then, of the conversation voice, basically only components of 1 kHz or more (reproduction frequency band) are reproduced by the tweeter 67 installed at the focus of the parabolic ceiling portion 17. That is, in the second embodiment, the system amplifies and reproduces the above reproduction frequency band by the tweeter 67, so that the voice is reproduced by emphasizing only the frequency band containing many consonant components. According to the second embodiment, it is possible to enjoy the same effects as the previous embodiment.

[0070] Next, another embodiment of the present invention will be described. FIG. 6 is a block diagram of a conference support system 1 according to a third embodiment of the present invention. In the conference support system 1 according to the third embodiment, The audio processing unit 40 employs a high-pass filter 42 that passes only electrical signals corresponding to sound components of 1 kHz or higher. The electrical signal that passes through the high-pass filter 42 has its level adjusted by a volume adjustment unit 41, and is amplified by an amplifier 50. The electrical signal amplified by the amplifier 50 is input to a tweeter 67 that reproduces sound components of 1 kHz or higher.

[0071] In this manner, in the conference support system 1 according to the third embodiment, both the high-pass filter 42 and the tweeter 67 are used, and this embodiment can also provide the same effects as the previous embodiments.

[0072] Next, another embodiment of the present invention will be described. In the embodiments described so far, a high-pass filter and tweeter are used to reproduce only electrical signals corresponding to sound components above a predetermined frequency (preferably 1 kHz or higher). In contrast, in the fourth embodiment, sounds below a predetermined frequency are cut as necessary, and components above 1 kHz (reproduction frequency band) are reflected by the parabolic ceiling portion 17 to be heard by the conference participants. Figure 7 is a block diagram of the audio processing portion 40 of the conference support system 1 according to the fourth embodiment of the present invention.

[0073] 7, the electrical signal converted by the microphone 30 is input to a high-pass filter 42, which passes only the electrical signal corresponding to components of a predetermined frequency or higher out of the electrical signal output from the microphone 30. The electrical signal converted by the microphone 30 is also input to a low-pass filter 43, which passes only the electrical signal corresponding to components of a predetermined frequency or lower out of the electrical signal output from the microphone 30.

[0074] A variable gain amplifier 44 is provided on the line on which the high-pass filter 42 is provided, and is set so as to obtain a gain at least greater than 1. On the other hand, an open / close switch 45 is provided on the line on which the low-pass filter 43 is provided, and this open / close switch 45 is provided near the desk 25 where it can be operated by the conference participants. The gain in the variable gain amplifier 44 is also configured so that it can be changed by an adjustment unit (not shown). It is preferable that the adjustment unit is also provided near the desk 25 and configured so that it can be operated and adjusted by the conference participants.

[0075] The line output from high-pass filter 42 and the line output from low-pass filter 43 are added together and input to volume adjustment unit 41. The level of the electrical signal is adjusted by volume adjustment unit 41, and the electrical signal is amplified by amplifier 50. The electrical signal amplified by amplifier 50 is input to speaker 60, and sound is reproduced from speaker 60 toward parabolic ceiling portion 17, as in the embodiments described so far.

[0076] The line on the low-pass filter 43 side is provided with an open / close switch 45, but even if the open / close switch 45 on the line on the low-pass filter 43 side is closed, the line on the high-pass filter 42 side is provided with a variable gain amplifier 44, so that the level of the electrical signal input to the volume adjustment unit 41 by adding the two is higher on the line on the high-pass filter 42 side. Therefore, the components of the sound reproduced by the speaker 60 are configured to emphasize components above a predetermined frequency (for example, 1 kHz or higher). As a result, in the conference support system 1 according to the fourth embodiment, a sound is reproduced in which a frequency band containing many consonant components is basically emphasized, making it easy to hear the sound.

[0077] On the other hand, in order to further improve the audibility of the conference participants, the open / close switch 45 can be opened to completely block sound components below a predetermined frequency. When the open / close switch 45 of the line on the low-pass filter 43 side is opened, the only electrical signal input to the volume adjustment unit 41 is the output from the line on the high-pass filter 42 side. As a result, the conference support system 1 according to the fourth embodiment can achieve the same effects as the previous embodiment.

[0078] Next, another embodiment of the present invention will be described. In the embodiments described so far, since the microphone 30 is present within the sound emission range (presentation range) of the speaker 60 and the parabolic ceiling portion 17, howling is expected to occur due to a loop such as sound input to the microphone 30 → amplification by the amplifier 50 → playback from the speaker 60 → sound input to the microphone 30. Therefore, in the fifth embodiment, a configuration for suppressing such howling is adopted.

[0079] 8 is a diagram illustrating an overview of a conference support system 1 according to a fifth embodiment of the present invention. The conference support system 1 according to the fifth embodiment can be arbitrarily combined with any of the first to fourth embodiments described above.

[0080] FIG. 8 shows four configurations for suppressing howling: a soundproofing plate 70 provided below the speaker 60, a cover body 80 provided above the microphone 30, a microphone stand 27 shaped like a truncated cone or a truncated pyramid for placing the microphone 30, and sound-absorbing material 90 laid on the desk 25.

[0081] In this embodiment, in order to suppress howling, each of the configurations may be used alone or in any combination.

[0082] The sound-proofing plate 70 is provided to prevent the sound reflected by the parabolic ceiling portion 17 from being picked up again by the microphone 30. It is preferable that the sound-proofing plate 70 and the microphone 30 are arranged so as to overlap each other in a plan view.

[0083] In addition, by providing the cover body 80 above the microphone 30, the microphone 30 is prevented from picking up sound from above the microphone 30, and the microphone 30 mainly picks up sound from the conference participants.

[0084] In addition, the shape of the microphone stand 27 on which the microphone 30 is placed is a truncated cone or a truncated pyramid, and by reflecting sound from the ceiling side approximately to the side, it prevents the microphone 30 from picking up sound reflected by the desk 25 from below.

[0085] In addition, the sound absorbing material 90 laid on the desk 25 absorbs sound incident from above, thereby preventing the microphone 30 from picking up sound reflected by the desk 25 from below.

[0086] In the above configuration, of the conversational voices recorded by the microphone 30, basically the components of 1 kHz or more (reproduction frequency band) are amplified and reproduced from the speaker 60 installed at the focus of the parabolic ceiling portion 17. Furthermore, in the conference support system 1 according to the fifth embodiment, the above-mentioned physical howling suppression measures are taken, and even if the howling frequency is within the reproduction frequency band, the diffraction effect of the sound insulation plate 70 or the sound absorption effect of the cover body 80 and the sound absorbing material 90 is high in the high frequency range, so that it is possible to sufficiently increase the amplification rate and improve the audibility of the voices. Furthermore, according to the fifth embodiment, the same effects as those of the previous embodiments can be enjoyed.

[0087] Next, a sixth embodiment of the present invention will be described. The conference support system 1 according to the sixth embodiment can be used in any combination with any of the first to fourth embodiments described above.

[0088] The conference support system 1 of the present invention is characterized in that sound emitted from a speaker 60 installed facing upward at the focus F of the parabolic ceiling portion 17 is reflected vertically downward by the parabolic ceiling portion 17 and is emitted within a limited area covered by the parabolic ceiling portion 17.

[0089] In such a conference support system 1 according to the present invention, if reflective objects R are placed in the range where sound is emitted (the area below the parabolic ceiling portion 17 in a plan view) as shown in Fig. 9, the sound reflected by the parabolic ceiling portion 17 will be reflected or scattered by these reflective objects R, causing the sound to propagate outside the range covered by the parabolic ceiling portion 17 from which the sound is intended to be emitted. Here, the configuration of the microphone 30 and the like is omitted in Fig. 9. Examples of the reflective object R include a display, a personal computer, a bookshelf, and a desk lamp.

[0090] In addition, as for desk 25, the upper surface of the tabletop is usually flat and parallel to floor surface 20, so sound reflected from the upper surface of the tabletop after being reflected by parabolic ceiling portion 17 returns in the direction of parabolic ceiling portion 17 and does not propagate outside the range where it is desired to emit sound, and therefore is not considered a reflecting object R here.

[0091] In order to solve the above problems, in the conference support system 1 according to the sixth embodiment, a sound insulating panel 70 is arranged flush with the horizontal plane that includes the uppermost end of the configuration including the housing 61 of the speaker 60. Fig. 10 is a diagram for explaining an overview of the conference support system 1 according to the sixth embodiment of the present invention.

[0092] The speaker 60 is composed of a magnet coil section 62 which serves as a vibration source, and a cone section 65 which is vibrated by the vibration source and thus serves as a vibration section which is essentially a sound source. However, the layout is such that the horizontal plane including the uppermost end of the cone portion 65 is flush with the upper surface of the sound insulating plate 70. The reason for such a layout will be described later.

[0093] Generally, the speaker 60 is not used by itself, but is used in a state where it is housed in a housing 61 such as an enclosure. The upper surface of the sound insulation plate 70 is laid out so as to be flush with the horizontal plane including the uppermost end of such housing 61. The reason for such a layout will be described later.

[0094] Note that housing 61 does not include a metal mesh or the like that is placed in front of cone portion 65 of speaker 60 to protect the cone portion 65. This is because such protective materials such as metal mesh are considered to be acoustically transparent. Housing 61 also does not include minute protrusions such as screws or bolts.

[0095] The installation range of the sound insulation board 70 is set to a range that overlaps with or exceeds the reflecting object R in a positional relationship in a plan view, so that the reflecting object R is included in the range of the sound insulation board 70. However, the range of the sound insulation board 70 is set to be narrower than the parabolic ceiling portion 17 in a plan view, and does not overlap with the conference participants, who are the targets from which sound is desired to be emitted.

[0096] The material and structure of the sound insulation board 70 need only have a certain degree of sound insulation performance (for example, an acoustic transmission loss of 10 dB or more is desirable) against the frequency components of the sound to be emitted. In addition, in the embodiment shown in Fig. 10, the shape of the sound insulation board 70 is circular in a plan view, but the planar shape of the sound insulation board 70 is not particularly limited to this, and the sound insulation board 70 can be rectangular, polygonal, irregular, etc. in a plan view.

[0097] Furthermore, at least the upper surface of the cross-sectional shape of the sound insulation board 70 is flat and parallel to the floor surface 20. However, this is based on the premise that the general ceiling portion 15 is parallel to the floor surface 20 and the parabolic ceiling portion 17 is installed so that the sound radiated from the speaker 60 is reflected perpendicularly to the floor surface 20.

[0098] In the conference support system 1 according to the sixth embodiment, the layout is such that a sound-proof panel 70 is arranged flush with the horizontal plane that includes the top end of the configuration including the housing 61 of the speaker 60. This is for the following reasons.

[0099] Figure 11 is a diagram explaining the difference in propagation paths based on the height of the focal point F and the height of the sound-proofing plate 70, where Figure 11(A) is a schematic diagram of the sound propagation path when the sound-proofing plate 70 is installed below the focal point, and Figure 11(B) is a schematic diagram of the sound propagation path when the top surface of the sound-proofing plate 70 is installed at the same height as the focal point.

[0100] As shown in FIG. 11(A), when the upper surface of the sound-proofing plate 70 is installed below the speaker 60, i.e., the focal point F, the sound that has traveled downward from the speaker is reflected by the upper surface of the sound-proofing plate 70 and then enters the parabolic ceiling portion 17. At this time, the direction of incidence coincides with the direction of incidence of the sound radiated from the virtual image F' of the focal point, which is located symmetrically to the focal point with the upper surface of the sound-proofing plate 70 as the symmetrical plane. For this reason, the reflection direction of the sound that has entered the parabolic ceiling portion 17 is not perpendicular downward to the floor surface 20, and the sound propagates outside the range that is covered by the parabolic ceiling portion 17 and from which it is desired to emit sound.

[0101] On the other hand, as shown in Fig. 11(B), if the upper surface of the soundproofing plate 70 is set at the same height as the uppermost end of the housing 61 in which the speaker 60 is housed, the virtual image of the focal point exists at the same position as the real image (original focal point), and such a problem does not occur. For this reason, in the conference support system 1 according to the sixth embodiment, the upper surface side of the soundproofing plate 70 is set at the same height as the uppermost end of the housing 61 of the speaker 60. Note that setting it in this manner is essentially equivalent to arranging the soundproofing plate 70 whose upper surface is flush with the horizontal plane that includes the uppermost end of the housing 61 in which the speaker 60 is housed.

[0102] In the conference support system 1 according to the sixth embodiment, the reason why the upper surface of the sound-proof board 70 is flat and parallel to the floor surface 20 (i.e., the horizontal plane) is as follows: Fig. 12 is a schematic diagram of a sound propagation path when the upper surface of the sound-proof board 70 is flat and parallel to the floor surface 20.

[0103] Sound (1) emitted from speaker 60 installed at focal point F enters parabolic ceiling portion 17 and is then reflected vertically downward (2). The sound reflected vertically downward from parabolic ceiling portion 17 enters the upper surface of sound insulation board 70, and if the upper surface of sound insulation board 70 is flat and parallel to the floor surface, the sound that enters the upper surface of sound insulation board 70 is reflected vertically upward (3) and then reflected again from parabolic ceiling portion 17 toward focal point F (4).

[0104] Thereafter, the sound is repeatedly reflected from focal point F of speaker 60 → parabolic ceiling portion 17 → upper surface of sound-proofing board 70 → parabolic ceiling portion 17 → focal point F of speaker 60 → ..., and does not propagate outside the desired range of sound emission covered by parabolic ceiling portion 17. For this reason, the upper surface of sound-proofing board 70 is made flat and parallel to floor surface 20.

[0105] Next, a speaker 60 that can be used in the conference support system 1 according to the sixth embodiment of the present invention will be described. According to the technology proposed in the present invention, it is required to install the speaker 60 at the focal point F of the parabolic ceiling portion 17, and in order to install the speaker 60 accurately at the focal position, it is preferable that the speaker 60 is small. However, a small speaker 60 generally has a wide directivity range over a wide frequency band, and as shown in FIG. 13, there is a problem that sound that has bent over from the speaker vibration portion to the side or downward does not enter the parabolic ceiling portion 17, but instead propagates directly outside the range where the sound is intended to be emitted.

[0106] By installing the sound-proofing board 70 of the conference support system 1 according to the sixth embodiment, as shown in Fig. 14, it is possible to obtain an effect of reducing the leakage of sound to the side or below the speaker 60 in a frequency band in which the wavelength is smaller than the size of the sound-proofing board 70. This makes it possible to more reliably emit sound within a range covered by the parabolic ceiling portion 17.

[0107] By using the sound-proofing plate 70 as in the sixth embodiment, it is not necessary to custom-make a speaker with a small speaker unit attached to a large housing in order to obtain the above-mentioned effects. The above-mentioned effects can be obtained by configuring a system using small speakers that are generally available on the market.

[0108] In the above configuration, of the conversational voices recorded by the microphone 30, basically the components of 1 kHz or more (reproduction frequency band) are amplified and reproduced from the speaker 60 installed at the focus of the parabolic ceiling portion 17. Furthermore, according to the conference support system 1 according to the sixth embodiment configured as described above, it is possible to prevent the sound reflected by the parabolic ceiling portion 17 from propagating to the area below the sound insulation plate 70 in a plan view. As a result, it is possible to prevent the sound from propagating beyond the range where it is originally intended to be emitted by being reflected or scattered by a reflecting object R such as a display located below the parabolic ceiling.

[0109] Furthermore, in the conference support system 1 of the sixth embodiment, even if the howling frequency is within the playback frequency band, the diffraction effect of the sound-proofing panel 70 is high in the high frequency range, so that it is possible to sufficiently increase the amplification rate and improve the audibility of the voice.

[0110] Moreover, according to the fifth embodiment, it is possible to obtain the same effects as those of the previous embodiments.

[0111] As described above, the conference support system of the present invention makes it possible to provide guidelines on how to amplify and play back audio recorded by a microphone so that it can be appropriately conveyed to the speaker and conference participants.

[0112] Furthermore, according to the conference support system of the present invention, it is possible to increase the amplification rate of the sound reproduced from the speaker, thereby making it possible to sufficiently increase the volume of the conversation sound transmitted to the speaker and conference participants.

[0113] In addition, according to the present invention, it is possible to prevent sound from propagating beyond the desired range, which results in more reliable provision of sound information such as background music and announcements within the range covered by the parabolic ceiling portion 17.

[0114] Furthermore, according to the present invention, it is possible to more reliably reduce the propagation of conversational voices to adjacent spaces by guiding the speaker to suppress the volume of their conversation while reliably transmitting the voice only to the conference participants who are having a conversation within the range covered by the parabolic ceiling section 17. As a result, it is possible to more reliably reduce the degree of decrease in the work efficiency of other workers working in adjacent spaces, reduce the degree of interference with other conversations taking place in adjacent spaces, and reduce the sense of noise in the entire workplace.

[0115] Furthermore, according to the present invention, when a highly confidential conversation is held in a meeting space, it is possible to more reliably prevent the contents of the conversation from being leaked to those around. [Explanation of symbols]

[0116] 1. Meeting support system 10. Ceiling 15...General ceiling section 17 Parabolic ceiling 20. Floor surface 25...Desk 27 Microphone stand 30. Microphone 40...Audio processing unit 41...Adjustment section 42 High-pass filter 43 Low-pass filter 44 Variable Gain Amplifier 45···Open / close switch 50 Amps 60···Speaker 61... Enclosure 62 Magnet coil section 65 Cone section 67 Tweeter 70 Soundproofing board 80 Cover body 90 Sound absorbing material R... Reflective object

Claims

1. A conference support system that collects audio from conference participants, plays the collected audio through a speaker, and outputs the audio to the conference participants to support the conference, A microphone that converts an input audio signal into an electrical signal; a filter that passes only an electrical signal corresponding to a component having a predetermined frequency or higher among the electrical signals converted by the microphone; an amplifier that amplifies the electrical signal that has passed through the filter; a speaker that reproduces the electrical signal amplified by the amplifier; A parabolic surface formed on a part of a ceiling that reflects the sound reproduced by the speaker; the predetermined frequency of the component corresponding to the electrical signal to be passed by the filter is 1 kHz or more; A conference support system comprising: a soundproofing panel that is flush with a horizontal plane that includes the top end of a structure including the housing of the speaker.

2. A conference support system that collects audio from conference participants, plays the collected audio through a speaker, and outputs the audio to the conference participants to support the conference, A microphone that converts an input audio signal into an electrical signal; an amplifier for amplifying the electrical signal converted by the microphone; a tweeter that reproduces only an electrical signal corresponding to a component having a predetermined frequency or higher among the electrical signals amplified by the amplifier; A parabolic surface formed on a part of a ceiling that reflects the sound reproduced by the tweeter; the predetermined frequency of the component corresponding to the electrical signal reproduced by the tweeter is 1 kHz or more; A conference support system comprising: a soundproofing panel that is flush with a horizontal plane that includes the top end of a structure including the housing of the speaker.

3. A conference support system that collects audio from conference participants, plays the collected audio through a speaker, and outputs the audio to the conference participants to support the conference, A microphone that converts an input audio signal into an electrical signal; a filter that passes only an electrical signal corresponding to a component having a predetermined frequency or higher among the electrical signals converted by the microphone; an amplifier that amplifies the electrical signal that has passed through the filter; a tweeter that reproduces only an electrical signal corresponding to a component having a predetermined frequency or higher among the electrical signals amplified by the amplifier; A parabolic surface formed on a part of a ceiling that reflects the sound reproduced by the tweeter; the predetermined frequency of the component corresponding to the electrical signal to be passed by the filter is 1 kHz or more; the predetermined frequency of the component corresponding to the electrical signal reproduced by the tweeter is 1 kHz or more; A conference support system comprising: a soundproofing panel that is flush with a horizontal plane that includes the top end of a structure including the housing of the speaker.

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