Meeting support system

Abstract

To provide a conference support system for clearly transmitting the voices of conference participants even when the conference participants wear masks or when a transparent partition is set up on a conference desk.SOLUTION: A conference support system includes microphones 30 and 30' for converting input audio signals into electrical signals, a first filter for passing only electrical signals corresponding to components of a first frequency or more out of the electrical signals converted by the microphones, a second filter for passing only electrical signals corresponding to components of a second frequency or more out of the electrical signals converted by the microphones, a setting unit 35 for setting either the first filter or the second filter, an amplifier for amplifying the electric signals that have passed through the filter set by the setting unit, a speaker 60 for reproducing the electric signals amplified by the amplifier, and a paraboloid 17 which is formed on a part of a ceiling 10 and reflects voices reproduced by the speaker.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] To provide a conference support system that can transmit the voices of conference participants clearly only to them in a meeting space or the like, without leaking the conversations of conference participants to nearby people, even when the conference participants are wearing masks or transparent partitions are installed on conference desks. [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 installation of open desks and the introduction of free addresses are being promoted, which make it easier for workers to approach each other and have conversations. Here, an open desk 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 tasks.

[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 different spaces are mixed together like this, there was an issue that conversations in meeting spaces or open desks could 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] Currently, due to the novel coronavirus (COVID-19) pandemic, measures to prevent infection have become commonplace, such as wearing masks during meetings and installing transparent partitions such as acrylic panels in meeting spaces. However, this has resulted in problems such as not being able to clearly hear conversations.

[0009] When meeting participants wear masks or transparent partitions are installed on meeting desks, it becomes more difficult to transmit sound. However, the above application does not specify the frequency characteristics of the speakers and other devices used to play back sound, and there is no description of how sound recorded by a microphone should be amplified and played back to transmit it to the speaker and meeting participants.

[0010] 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]

[0011] The present invention solves the above-mentioned problems, and the conference support system of the present invention supports a conference by collecting speech by conference participants, playing the collected speech through a speaker and presenting it to the conference participants, and is characterized in having a microphone that converts an input audio signal into an electrical signal, a first filter that passes only electrical signals corresponding to components of a first frequency or higher from the electrical signals converted by the microphone, a second filter that passes only electrical signals corresponding to components of a second frequency or higher from the electrical signals converted by the microphone, a setting unit that sets either the first filter or the second filter, an amplifier that amplifies the electrical signal that has passed through the filter set by the setting unit, a speaker that plays the electrical signal amplified by the amplifier, and a parabolic surface formed on a part of the ceiling that reflects the sound played by the speaker.

[0012] In addition, the conference support system of the present invention supports a conference by collecting speech by conference participants, playing the collected speech through a speaker and presenting it to the conference participants, and is characterized in having a microphone that converts an input audio signal into an electrical signal, an amplifier that amplifies the electrical signal converted by the microphone, a first tweeter that reproduces only an electrical signal corresponding to a first frequency or higher component from the electrical signal amplified by the amplifier, a second tweeter that reproduces only an electrical signal corresponding to a second frequency or higher component from the electrical signal amplified by the amplifier, a setting unit that sets either the first tweeter or the second tweeter, and a parabolic surface formed on a part of the ceiling that reflects the sound reproduced by the tweeter set by the setting unit.

[0013] In addition, the conference support system of the present invention supports the conference by collecting speech by conference participants and playing the collected speech through a speaker to present it to the conference participants, and is characterized in having a microphone that converts an input audio signal into an electrical signal, an equalizer that adjusts the amount of amplification for each frequency band of the electrical signal converted by the microphone, a setting unit that sets the equalizer to either increase the amount of amplification of a frequency band equal to or higher than a first frequency, or increase the amount of amplification of a frequency band equal to or higher than a second frequency, an amplifier that amplifies the electrical signal that has passed through the equalizer, a speaker that plays the electrical signal amplified by the amplifier, and a parabolic surface formed on a part of the ceiling that reflects the sound played by the speaker.

[0014] In addition, the conference support system according to the present invention is characterized in that the first frequency is 1 kHz.

[0015] In addition, the conference support system according to the present invention is characterized in that the second frequency is a lower limit frequency of a 1 / 3 octave band having a center frequency of 2.5 kHz.

[0016] The conference support system according to the present invention is characterized in that a sound insulating panel is disposed below the speaker. Effect of the Invention

[0017] The conference support system according to the present invention uses a filter to emphasize consonants when playing back, so that voices can be transmitted clearly to conference participants even if they are wearing masks. Furthermore, in the conference support system according to the present invention, the setting unit sets either a first filter that is suitable when a partition is installed, or a second filter that is suitable when a partition is not installed, so that such a conference support system according to the present invention can transmit voices clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

[0018] In addition, in the conference support system of the present invention, either the first tweeter or the second tweeter is set by the setting unit depending on the installation status of the partition, so that voice can be transmitted clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

[0019] In addition, in the conference support system of the present invention, the setting unit appropriately adjusts the amount of amplification for each frequency band in the equalizer depending on the installation status of the partition, so that voice can be clearly transmitted to conference participants regardless of whether a transparent partition is installed on the conference desk.

[0020] 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.

[0021] 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. [Brief description of the drawings]

[0022] [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] 11 is a diagram showing frequency dependence of the amount of attenuation of sound when the sound is diffracted at the end of the partition 100. FIG. [Figure 4] 2 is a diagram illustrating the geometric arrangement of a speaker 60 and a ceiling in the conference support system 1. FIG. [Diagram 5] 1 is a diagram illustrating reflected sound from a parabolic ceiling portion 17 of the conference support system 1. FIG. [Figure 6]FIG. 1 is a block diagram of a conference support system 1 according to a second embodiment of the present invention. [Figure 7] FIG. 11 is a block diagram of a conference support system 1 according to a third embodiment of the present invention. [Figure 8] FIG. 1 is a diagram illustrating an overview of a conference support system 1 according to a fourth embodiment of the present invention. [Figure 9] 11 is a diagram illustrating a case where a sound reflecting object is placed within the sound presentation range. FIG. [Figure 10] FIG. 11 is a diagram illustrating an overview of a conference support system 1 according to a fifth 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 fifth embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] 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 a meeting space provided in the vicinity of, for example, a large desk in a free address style where work is carried out or an open desk.

[0024] In addition, it is expected that employees will work at the large desks and open desks in the free address style mentioned above, while meetings will take place in meeting spaces where meeting participants can speak.

[0025] In this specification, an "office worker" is defined as someone who performs desk work such as paperwork and computer input work and who generally does not speak, and is distinguished from a conference participant who takes part in a conference in the meeting space and speaks.

[0026] The conference support system 1 according to the present invention aims to present appropriate audio to the conference participants while preventing the contents of the conversation between the participants in the meeting space from being heard by other workers at nearby large desks or open desks as much as possible. To achieve this, the conference support system 1 according to the present invention collects the voices of the conference participants (speakers) and plays back the collected voices through a speaker to present them to the conference participants, thereby supporting the conference.

[0027] In the conference support system 1 of the present invention, attention is paid to the characteristics of voice and hearing, and the characteristics of voice attenuation due to masks and partitions, and the frequency characteristics of the voice played from the speaker 60 are specified, thereby enabling the voice to be transmitted clearly to the conference participants.

[0028] 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.

[0029] In the conference support system 1 of the present invention, when the collected speech 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.

[0030] 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 with two participants at a desk 25 placed on a floor surface 20. It is assumed that in the vicinity of this desk 25, workers are working at the aforementioned large free-address type desk or an open desk (neither of which are shown in the figure), or the like.

[0031] It is assumed that the conference participants will wear masks 110 as a measure against infection. In addition to the infection countermeasure using masks 110, in some cases partitions 100 are provided on desks 25 to separate conference participants from each other. Note that such partitions 100 may or may not be installed, but the state of sound propagation differs greatly depending on whether or not the partitions are installed. Therefore, in the conference support system 1 according to the present invention, the system settings are changed depending on whether the partitions are installed or not.

[0032] In the following, the present embodiment will be described on the assumption that a partition 100 is provided on the desk 25. In addition, in the present embodiment, a single partition 100 is provided between two conference participants, and the two conference participants are separated into two spaces, but the number of partitions provided and the number of spaces separated by the partitions are not limited to this. In addition, as a method of installing microphones, a microphone may be provided for each space separated by a partition to collect the voices of the conference participants for each space, or a microphone may be suspended below the speaker 60 to collect the voices of the conference participants.

[0033] In this embodiment, microphones 30, 30' are installed in each space above desk 25, and these microphones 30, 30' pick up the sounds of the respective conference participants. When an audio signal resulting from the speech is input, the microphones 30, 30' convert this into an electrical signal.

[0034] The electrical signals converted by the microphones 30, 30' are input to an audio processor 40. In this audio processor 40, the electrical signals are converted into signals suitable for playback by a speaker 60. FIG. 2 is a block diagram of the audio processor 40 of the conference support system 1 according to an embodiment of the present invention. The audio processor 40 in FIG. 2 is one example, and various other embodiments are possible. In the subsequent stage of the audio processor 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.

[0035] In FIG. 2, the electrical signals converted by the microphones 30 and 30 ′ are input to either a first filter 47 or a second filter 48 in the audio processing unit 40 .

[0036] The first filter 47 is a high-pass filter that passes only electrical signals corresponding to components of a first frequency (1 kHz) or higher among the electrical signals converted by the microphones 30 and 30'. The second filter 48 is a high-pass filter that passes only electrical signals corresponding to components of a second frequency (the lower limit frequency (approximately 2.23 kHz) of a 1 / 3 octave band with a center frequency of 2.5 kHz) or higher among the electrical signals converted by the microphones 30 and 30'.

[0037] The setting section 35 sets whether the electrical signals from the microphones 30 and 30 ′ are to be passed through the first filter 47 or the second filter 48 .

[0038] When the electrical signals from the microphones 30, 30′ are to pass through the first filter 47, the setting unit 35 turns on the first switch 37 and turns off the second switch 38. When the partition 100 is provided on the desk 25, the setting is made to pass the electrical signals from the microphones 30, 30′ through the first filter 47.

[0039] When the electrical signals from the microphones 30, 30' are to pass through the second filter 48, the setting unit 35 turns off the first switch 37 and turns on the second switch 38. When the partition 100 is not provided on the desk 25, the setting is made to pass the electrical signals from the microphones 30, 30' through the second filter 48.

[0040] The setting in the setting unit 35 may be performed manually by a person determining whether or not the partition 100 is present on the desk 25, or it may be performed automatically, for example by acquiring an image of the desk 25 and determining whether or not the partition 100 is present on the desk 25 through image analysis or the like.

[0041] Next, the reason why the setting unit 35 selectively sets either the first filter 47 that passes only electrical signals corresponding to components equal to or greater than a first frequency (1 kHz) or the second filter 48 that passes only electrical signals corresponding to components equal to or greater than a second frequency (the lower limit frequency of a 1 / 3 octave band with a center frequency of 2.5 kHz) will be described below.

[0042] Most syllables in Japanese are composed of consonants and vowels, each of which has different frequency characteristics. According to Reference 1, consonants have components mainly in the high frequency band (1k to 6kHz) compared to vowels. And according to Reference 2, consonants are said to play an important role in conveying speech clearly in Japanese conversation.

[0043] On the other hand, according to Reference 3, when a speaker wears a mask made of commonly used nonwoven fabric or cloth, there is a significant attenuation of the components of the voice contained in the 1 / 3 octave band with a center frequency of 2.5 kHz or the 1 / 3 octave band with a center frequency of 3.15 kHz or higher. The main components of consonants, which play an important role in the clarity of conversation, are contained in these bands, and the attenuation of these bands makes it difficult to transmit conversational voices clearly.

[0044] In addition, when partition 100 is placed between the speaker and the other conference participants, the propagation path of the voice that would reach the conference participants directly from the speaker if partition 100 were not present is now composed of a path that reaches the conference participants by diffracting at the end of partition 100, and a path that reaches the speaker's side of partition 100, passes through partition 100, and is re-radiated from the opposite side.

[0045] Among these, in the path where sound diffracts at the end of the partition 100, the sound is attenuated due to the diffraction effect, but the amount of attenuation is generally greater as the frequency is higher. Also, in the path where sound penetrates the partition 100, the sound is attenuated as it penetrates the partition 100 made of a plate or film material, but the amount of attenuation is generally greater as the frequency is higher.

[0046] Therefore, when partition 100 is placed between the speaker and other conference participants, the high frequency components of the voice are attenuated more than when there is no partition 100. As described above, the main components of consonants are in a higher frequency range (1 kHz to 6 kHz) compared to vowels, and attenuation of this range makes it difficult to clearly transmit conversational voices.

[0047] Figure 3 shows an example of the attenuation of sound when diffracted at the edge of the partition 100, predicted using the formula shown in Reference 4. The values ​​on the vertical axis represent the attenuation based on the case where there is no partition. The prediction conditions are as follows: The distance between the speaker and other meeting participants should be 2m, and their heads should be at the same height. The partition 100 is installed in the center between the two people, and its width extends 0.75 m on both sides in a direction perpendicular to the line connecting the two people. Also, its height is 1 m above the head position of both people. The sound propagation path is assumed to be a path that diffracts at the top and both sides of the partition 100. In other words, the bottom end of the partition 100 is in contact with the desk 25, and sound does not propagate along the path that diffracts at the bottom end. The calculation result is a combination of the calculation results for each path. The path of sound that passes through the partition 100 is not taken into consideration here. For example, if we assume that the partition 100 is made of a 4 mm thick acrylic plate, which is thick enough to be self-supporting, then under the above conditions, at frequencies of 500 Hz or higher, the sound that passes through the partition 100 is sufficiently small compared to the sound that is diffracted at the edge of the partition 100.

[0048] 3, it can be seen that at 1 kHz, the attenuation due to diffraction is 13 dB or more, and the degree of attenuation increases as the frequency increases. As mentioned above, the path through the partition 100 is not considered here, but the tendency remains the same even if this is taken into consideration.

[0049] In view of the above, the conference support system 1 according to the present invention is a system that amplifies and plays back the speaker's voice so that the conversation voice can be clearly transmitted to other conference participants. However, instead of amplifying all frequency components of the voice, the system amplifies and reproduces the voice by emphasizing only the above-mentioned reproduction frequency band, which plays an important role in the clarity of voice transmission and contains many consonant components that are easily attenuated by the mask 110 or partition 100.

[0050] Therefore, when the partition 100 is installed, the reproduction frequency band is set to 1 kHz or more, and in the conference support system 1 according to the present invention, the first filter 47 cuts frequencies below the first frequency (1 kHz) and reproduces the sound from the speaker 60. This has the advantage that the clarity of the conversation voice can be efficiently improved and the occurrence of howling can be suppressed compared to the case where all frequency components of the sound are amplified.

[0051] From the viewpoint of suppressing feedback, it is desirable for the reproduction frequency band to be as narrow as possible, and therefore, under the condition where only the mask 110 is worn and the partition 100 is not installed, the reproduction frequency band is set to be equal to or higher than the lower limit frequency (approximately 2.23 kHz) of the 1 / 3 octave band with a center frequency of 2.5 kHz, based on the results shown in Reference 3. That is, in the conference support system 1 according to the present invention, when the partition 100 is not present, the second filter 48 cuts off frequencies below the second frequency (the lower limit frequency (approximately 2.23 kHz) of the 1 / 3 octave band with a center frequency of 2.5 kHz).

[0052] Similarly, according to Reference 1, the frequency band containing the main components of consonants is 1 kHz to 6 kHz. Therefore, the reproduction frequency band of speaker 60 may be set to be equal to or higher than the lower limit frequency (or 1 kHz) of the 1 / 3 octave band with a center frequency of 2.5 kHz and equal to or lower than 6 kHz. In other words, instead of second filter 48, which is a high-pass filter, it is also possible to use a band-pass filter with a pass band of 1 kHz to 6 kHz.

[0053] In the present invention, the playback frequency band is basically 1 kHz or more, and also includes a band of 6 kHz or more. The reason is that, although it is weaker than the band from 1 kHz to 6 kHz, the band of 6 kHz or more also contains consonant components. In addition, even if the energy of consonants is minute, they affect the clarity of conversation (Reference 2), so the playback frequency band includes 6 kHz or more, even though it does not contain the main components.

[0054] The amount of attenuation of conversational voices by mask 110 is shown in, for example, Reference 3. Furthermore, if the material and dimensions constituting partition 100 and the installation conditions are known, the amount of attenuation of voice in the path diffracted at the end of partition 100 and the path passing through partition 100 can be predicted for each frequency using known formulas and charts. In this case, if a device capable of adjusting the amount of amplification for each frequency band, such as a graphic equalizer, is used as the device constituting the present invention, it is effective to set the amount of amplification for each frequency band belonging to the playback frequency band to be equal to or greater than the above-mentioned amount of attenuation.

[0055] Returning to Fig. 2, the output from either the first filter 47 or the second filter 48 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 components such as an input knob, an input slider, etc. for adjusting the volume are appropriately provided on the desk 25.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] 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 presented to a limited area (a meeting space where desks 25 are arranged) even when a general speaker is used. Figure 4 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.

[0060] 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 a coordinate system (x, y) is defined with the position F of the speaker 60 (not shown in FIG. 4) as the origin.

[0061] 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 F of the paraboloid ceiling portion 17.

[0062] 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.

[0063] The playback sound presenting 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 also installed so as to be located at the focal point F of the paraboloid of the ceiling 10.

[0064] In the above-mentioned relationship, when speaker 60 is placed at F, as shown in FIG. 5, sound reflected from parabolic ceiling portion 17 travels vertically downward toward floor surface 20.

[0065] 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.

[0066] 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 is then reflected 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 of presentation 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.

[0067] 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.

[0068] 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.

[0069] 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 presented only directly below the parabolic ceiling portion 17.

[0070] In this way, by appropriately setting the directional range of the parabolic ceiling portion 17 and the speaker 60 so as to cover the meeting space, the sound recorded by the microphones 30, 30' is reliably transmitted only to the conference participants who are conversing in the meeting space.

[0071] 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.

[0072] 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.

[0073] 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.

[0074] The microphones 30, 30' used in the conference support system 1 according to the present invention are preferably installed on the desk 25. However, it is also possible to use lapel microphones worn by the conference participants who will be having a conversation.

[0075] According to the conference support system 1 of the present invention configured as described above, it is possible to prevent conversations in a meeting space, etc. from being heard by other nearby workers, thereby preventing a decrease in the productivity of the other workers, without having to take measures such as surrounding the meeting space with a dividing partition.

[0076] The conference support system 1 according to the present invention can transmit voices clearly to conference participants even if they are wearing masks by emphasizing consonants when playing back using either the first filter 47 or the second filter 48. Furthermore, in the conference support system 1 according to the present invention, the setting unit sets either the first filter suitable for when the partition 100 is installed or the second filter suitable for when the partition 100 is not installed, so that such a conference support system according to the present invention can transmit voices clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

[0077] Furthermore, according to the conference support system 1 of the present invention, by providing a high-pass filter 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.

[0078] 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.

[0079] 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.

[0080] 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.

[0081] In addition, the speaker can be effectively fed back his / her own voice, which can effectively guide the speaker to reduce the volume of his / her voice, thereby reducing the degree to which conversation voice leaks into adjacent spaces.

[0082] 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.

[0083] 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.

[0084] The above-mentioned effects can be obtained without increasing the amplification factor of the sound reproduced by the speaker 60. In other words, the degree to which the reproduced sound leaks to the surroundings can be suppressed, and the above-mentioned effects can be obtained even with an amplification factor that does not cause howling. On the other hand, when the howling frequency is outside the reproduction frequency band, it is possible to sufficiently increase the amplification factor.

[0085] Furthermore, even if the howling frequency is within the playback frequency band, the diffraction effect of the shielding plate and the sound absorption effect of the sound-absorbing material are strong in the high frequency range, so by combining it with physical methods such as the shielding plate described in Patent Document 2, howling can be effectively suppressed and the amplification rate can be sufficiently increased.

[0086] 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.

[0087] 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 F, 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.

[0088] 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, such as in a Web conference.

[0089] Next, another embodiment of the present invention will be described. In the previous embodiment, the high-pass filter of either the first filter 47 or the second filter 48 passes only the electrical signal corresponding to a component of a predetermined frequency or higher among the electrical signals output from the microphones 30, 30', and reproduces the signal from the speaker 60.

[0090] On the other hand, in the second embodiment, such a high-pass filter is not used, and the speaker 60 is replaced with a tweeter to reproduce components above a predetermined frequency. The other configurations are the same as those of the first embodiment. FIG. 6 is a block diagram of such a conference support system 1 according to the second embodiment of the present invention. As in the previous embodiment, the second embodiment is also configured so that the sound reproduced by the tweeter is reflected by a parabolic ceiling portion 17 formed on a part of the ceiling.

[0091] In this specification, the first 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, and the second tweeter 68 is defined as a speaker that reproduces sound components of the lower limit frequency of a 1 / 3 octave band of a center frequency of 2.5 kHz or more and does not reproduce sound components of less than the lower limit frequency of a 1 / 3 octave band of a center frequency of 2.5 kHz.

[0092] The setting unit 35 in the second embodiment sets whether the electrical signals from the microphones 30, 30' are to be reproduced by the first tweeter 67 or the second tweeter 68. When reproducing sound by the first tweeter 67, the setting unit 35 turns on the first switch 37 and turns off the second switch 38. When reproducing sound by the second tweeter 68, the setting unit 35 turns off the first switch 37 and turns on the second switch 38.

[0093] Moreover, the setting unit 35 in the second embodiment has a function of setting whether the tweeter to be arranged at the focal point F is the first tweeter 67 or the second tweeter 68. In order to realize this function, it is preferable that the setting unit 35 has a driving unit 69 such as an actuator (not shown). The setting unit 35 operates such a driving unit 69 to position either the first tweeter 67 or the second tweeter 68 at the focal point F. Of course, the tweeter to be arranged at the focal point F may be manually set.

[0094] The settings in the setting unit 35 as described above may be performed manually by a person determining whether or not the partition 100 is present on the desk 25, or may be performed automatically, for example, by acquiring an image of the desk 25 and determining whether or not the partition 100 is present on the desk 25 through image analysis or the like.

[0095] In the conference support system 1 according to the second embodiment, the conversation voice recorded by the microphones 30, 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. When the partition 100 is provided on the desk 25, the setting unit 35 sets the voice to be reproduced by the first tweeter 67, and when the partition 100 is not provided on the desk 25, the setting unit 35 sets the voice to be reproduced by the second tweeter 68. That is, in the second embodiment, the system amplifies and reproduces the above-mentioned reproduction frequency band by the first tweeter 67 and the second tweeter 68, so that the voice is reproduced by emphasizing only the frequency band containing many consonant components. According to the second embodiment, the same effects as those of the previous embodiment can be enjoyed.

[0096] In the conference support system 1 of the second embodiment, either the first tweeter 67 or the second tweeter 68 is set by the setting unit 35 depending on the installation status of the partition, so that voice can be clearly transmitted to conference participants regardless of whether a transparent partition 100 is installed on the conference desk 25 or not.

[0097] Next, another embodiment of the present invention will be described. FIG. 7 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 has an equalizer 49 that adjusts the amount of amplification for each frequency band of the electrical signals converted by the microphones 30, 30', and the level of the electrical signals passing through the equalizer 49 is adjusted by the volume adjustment unit 41 and amplified by the amplifier 50. The electrical signals amplified by the amplifier 50 are input to the speaker 60 where they are reproduced.

[0098] The setting unit 35 according to the third embodiment sets the equalizer 49 to either increase the amount of amplification of a frequency band equal to or greater than a first frequency (1 kHz) or to increase the amount of amplification of a frequency band equal to or greater than a second frequency (the lower limit frequency of a 1 / 3 octave band with a center frequency of 2.5 kHz). In the former case, it is preferable to decrease the amount of amplification of a frequency band below the first frequency (1 kHz), and in the latter case, to decrease the amount of amplification of a frequency band below the second frequency (the lower limit frequency of a 1 / 3 octave band with a center frequency of 2.5 kHz).

[0099] In this manner, in the conference support system 1 of the third embodiment, when a partition 100 is provided on the desk 25, the equalizer 49 is adjusted by the setting unit 35 so that audio with the frequency band above the first frequency (1 kHz) emphasized is reproduced from the speaker 60. Furthermore, when the partition 100 is not provided on the desk 25, the equalizer 49 is adjusted by the setting unit 35 so that sound in which the frequency band equal to or higher than the second frequency (the lower limit frequency of the 1 / 3 octave band with a center frequency of 2.5 kHz) is emphasized is reproduced from the speaker 60. The setting in the setting unit 35 can be either manual or automatic, as in the embodiments described so far.

[0100] The conference support system 1 according to the third embodiment can also provide the same effects as those of the previous embodiments.

[0101] In the conference support system 1 of the third embodiment, the setting unit 35 appropriately adjusts the amount of amplification for each frequency band in the equalizer 49 depending on the installation status of the partition 100, so that voice can be clearly transmitted to conference participants regardless of whether a transparent partition 100 is installed on the conference desk 25 or not.

[0102] Next, another embodiment of the present invention will be described. In the embodiment described so far, since the microphone 30 is present within the range of sound presentation by 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.

[0103] Therefore, in the fourth embodiment, a configuration for suppressing such feedback is adopted.

[0104] 8 is a diagram illustrating an overview of a conference support system 1 according to a fourth embodiment of the present invention. The conference support system 1 according to the fourth embodiment can be arbitrarily combined with any of the first to fourth embodiments described above.

[0105] FIG. 8 shows four configurations for suppressing howling: a sound-proofing plate 70 provided below the speaker 60; cover bodies 80, 80' provided above the microphones 30, 30'; microphone stands 27, 27' shaped like a truncated cone or a truncated pyramid on which the microphones 30, 30' are placed; and sound-absorbing material 90 laid on the desk 25.

[0106] In this embodiment, in order to suppress howling, each of the configurations may be used alone or in any combination.

[0107] 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 microphones 30, 30' overlap each other in a plan view.

[0108] In addition, by providing the cover bodies 80, 80' above the microphones 30, 30', the microphones 30, 30' are prevented from picking up sound from above the microphones 30, 30', and sound is mainly collected from the speech of the conference participants.

[0109] In addition, the shape of the microphone stands 27, 27' on which the microphones 30, 30' are placed is a truncated cone or a truncated pyramid, and by reflecting sound from the ceiling side approximately to the side, it is possible to prevent the microphones 30, 30' from picking up sound reflected by the desk 25 from below.

[0110] Furthermore, the sound absorbing material 90 laid on the desk 25 absorbs sound incident from above, thereby preventing the microphones 30, 30' from picking up sound reflected by the desk 25 from below.

[0111] In the above configuration, among the conversational voices recorded by the microphones 30, 30', basically, components of 1 kHz or more or the lower limit frequency of the 1 / 3 octave band with a center frequency of 2.5 kHz or more are amplified and reproduced from the speaker 60 (or tweeter) installed at the focus of the parabolic ceiling part 17. Furthermore, in the conference support system 1 according to the fourth 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 voice. Furthermore, according to the fourth embodiment, the same effects as those of the previous embodiment can be enjoyed.

[0112] Next, a fifth embodiment of the present invention will be described. The conference support system 1 according to the fifth embodiment can be used in any combination with any of the first to fourth embodiments described above.

[0113] 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 presented within a limited area covered by the parabolic ceiling portion 17.

[0114] In such a conference support system 1 according to the present invention, if a partition 100 is placed in the range where sound is presented (the area below the parabolic ceiling portion 17 in a plan view) as shown in Fig. 9, there is a problem that sound reflected by the parabolic ceiling portion 17 is reflected or scattered by the partition 100, and the sound propagates outside the range covered by the parabolic ceiling portion 17 where the sound is intended to be presented. Here, the configuration of the electrical system such as the microphones 30, 30' is omitted in Fig. 9. Other examples of sound reflecting objects on the desk 25 include, for example, a display, a personal computer, a bookshelf, and a desk lamp.

[0115] 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 from parabolic ceiling portion 17 returns in the direction of parabolic ceiling portion 17 and does not propagate outside the range in which the sound is desired to be presented, and therefore it is not considered a sound reflector here.

[0116] In order to solve the above problems, in the conference support system 1 according to the fifth embodiment, a sound insulating plate 70 is arranged flush with the horizontal plane including 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 fifth embodiment of the present invention. Fig. 10 does not show the configuration of the electrical system of the microphones 30, 30', etc.

[0117] 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 this vibration source and thereby serves as a vibrating section which essentially serves as a sound source.

[0118] 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.

[0119] 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.

[0120] The installation range of the sound insulation board 70 is set to a range that overlaps with or exceeds the sound reflecting objects in a planar positional relationship, so that the sound reflecting objects are included in the range of the sound insulation board 70. However, the range of the sound insulation board 70 is set to a range narrower than the parabolic ceiling portion 17 in a planar view, and does not overlap with the conference participants to whom the sound is to be presented.

[0121] The material and structure of the sound-proofing board 70 need only have a certain degree of sound-proofing performance against the frequency components of the sound to be presented (for example, an acoustic transmission loss of 10 dB or more is desirable). In the embodiment shown in Fig. 10, the shape of the sound-proofing board 70 is circular in a plan view, but the planar shape of the sound-proofing board 70 is not particularly limited to this, and the sound-proofing board 70 can be rectangular, polygonal, irregular, etc. in a plan view.

[0122] 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.

[0123] In the conference support system 1 according to the fifth 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.

[0124] 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.

[0125] As shown in FIG. 11(A), when the upper surface of the sound-proofing plate 70 is placed 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 the parabolic ceiling portion 17 covers and that is intended to present.

[0126] 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 fifth 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.

[0127] In the conference support system 1 according to the fifth 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.

[0128] 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).

[0129] 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 the sound does not propagate outside the range that is desired to be presented and is 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.

[0130] Next, a speaker 60 that can be used in the conference support system 1 according to the fifth 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 (electrical system not shown), 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 presented.

[0131] By installing the sound insulation board 70 of the conference support system 1 according to the fifth embodiment, as shown in Fig. 14 (electrical system not shown), there is an effect that the leakage of sound to the side or below the speaker 60 can be reduced in a frequency band whose wavelength is smaller than the size of the sound insulation board 70. This makes it possible to more reliably present sound within a range covered by the parabolic ceiling portion 17.

[0132] By using the sound-proofing plate 70 as in the fifth 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.

[0133] In the above configuration, of the conversational voices recorded by the microphones 30, 30', basically, components of frequencies above 1 kHz or above the lower limit frequency of a 1 / 3 octave band with a center frequency of 2.5 kHz 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 of the fifth 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 reproduced sound from being reflected or scattered by a reflecting object such as the partition 100 located below the parabolic ceiling, and thus the sound from propagating beyond the range where it is originally intended to be presented.

[0134] Furthermore, in the conference support system 1 according to the fifth 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.

[0135] Moreover, according to the fifth embodiment, it is possible to obtain the same effects as those of the previous embodiments.

[0136] As described above, the conference support system of the present invention can prevent conversations in a meeting space, etc. from being heard by other nearby workers, thereby reducing the productivity of those other workers, without the need to take measures such as surrounding the meeting space with a dividing partition.

[0137] The conference support system 1 according to the present invention uses either the first filter or the second filter to emphasize consonants when playing back, so that voices can be transmitted clearly to conference participants even if they are wearing masks. Furthermore, in the conference support system according to the present invention, the setting unit sets either the first filter, which is suitable when a partition is installed, or the second filter, which is suitable when a partition is not installed, so that such a conference support system according to the present invention can transmit voices clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

[0138] In addition, in the conference support system of the present invention, either the first tweeter or the second tweeter is set by the setting unit depending on the installation status of the partition, so that voice can be transmitted clearly to conference participants regardless of whether a transparent partition is installed on the conference desk.

[0139] In addition, in the conference support system of the present invention, the setting unit appropriately adjusts the amount of amplification for each frequency band in the equalizer depending on the installation status of the partition, so that voice can be clearly transmitted to conference participants regardless of whether a transparent partition is installed on the conference desk.

[0140] 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.

[0141] In addition, according to the conference support system of the present invention, by providing the above-mentioned filters and tweeters, it is possible to increase the amplification rate of the sound reproduced from the speaker, thereby sufficiently increasing the volume of the conversation sound transmitted to the speaker and conference participants.

[0142] 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.

[0143] In addition, according to the conference support system of the present invention, when the howling frequency is outside the playback frequency band, it is possible to sufficiently increase the amplification factor, which also improves audio transmissibility to conference participants.

[0144] In addition, according to the conference support system of the present invention, it is possible to reliably transmit sound only to conference participants within the area covered by the parabolic surface on the ceiling, while guiding speakers to reduce their speaking volume.

[0145] In addition, the speaker can be effectively fed back his / her own voice, which can effectively guide the speaker to reduce the volume of his / her voice, thereby reducing the degree to which conversation voice leaks into adjacent spaces.

[0146] 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.

[0147] Furthermore, according to the conference support system 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.

[0148] The above-mentioned effects can be obtained without increasing the amplification factor of the sound reproduced by the speaker. In other words, the degree to which the reproduced sound leaks to the surroundings can be suppressed, and the above-mentioned effects can be obtained even with an amplification factor that does not cause howling. On the other hand, if the howling frequency is outside the reproduction frequency band, it is possible to sufficiently increase the amplification factor.

[0149] Furthermore, even if the howling frequency is within the playback frequency band, the diffraction effect of the shielding plate and the sound absorption effect of the sound-absorbing material are strong in the high frequency range, so by combining it with physical methods such as the shielding plate described in Patent Document 2, howling can be effectively suppressed and the amplification rate can be sufficiently increased.

[0150] In addition, in the conference support system according to the present invention, if a microphone installed on a desk is used, there is no need for a wearable device such as an intercom, and the above-mentioned effects can be obtained without compromising convenience. Wearing an intercom or the like not only reduces convenience, but also causes discomfort for workers who are not accustomed to it, which can lead to a decrease in the efficiency of the meeting.

[0151] In addition, in the conference support system according to the present invention, a general speaker can be used as the speaker installed at the focal point F, 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.

[0152] Furthermore, the conference support system according to the present invention is effective not only when actually conducting face-to-face conversations, but also when conducting conversations with remote parties, such as in Web conferences. Reference 1: Acoustics Science Series 21: Children's Voices, edited by the Acoustical Society of Japan, Corona Publishing, 2019 Reference 2: Architectural and Environmental Acoustics, 3rd Edition, Junichi Maekawa, Masayuki Morimoto, Kimihiro Sakagami, Kyoritsu Shuppan, 2011 Reference 3: “Acoustic effects of medical, cloth, and transparent face masks on speech signals,” RM Corey, U. Jones, and AC Singer, J. Acoust. Soc. Am., Vol. 148, 2371, 2020. (https: / / doi.org / 10.1121 / 10.0002279) Reference 4: “Prediction model of road traffic noise “ASJ RTN-Model 2018””, Road Traffic Noise Research Committee of the Acoustical Society of Japan, Journal of the Acoustical Society of Japan, Vol. 75, No. 4, pp. 188-250, 2019. [Explanation of symbols]

[0153] 1. Meeting support system 10. Ceiling 15...General ceiling section 17 Parabolic ceiling 20. Floor surface 25...Desk 27, 27' Microphone stand 30, 30'...Microphone 35. Setting section 37 First switch 38 Second switch 40...Audio processing unit 41...Adjustment section 43 Low-pass filter 44 Variable Gain Amplifier 45···Open / close switch 47 First filter 48 Second filter 49. Equalizer 50 Amps 60···Speaker 61... Enclosure 62 Magnet coil section 65 Cone section 67···1st tweeter 68···Second tweeter 69 Drive unit 70 Soundproofing board 80, 80'···Cover body 90 Sound absorbing material 100···Partition 110... Mask

Claims

1. A conference support system that supports a conference by collecting speech from conference participants, playing the collected speech through a speaker, and presenting the speech to the conference participants, A microphone that converts an input audio signal into an electrical signal; a first filter that passes only an electrical signal corresponding to a component having a first frequency or higher among the electrical signals converted by the microphone; a second filter that passes only an electrical signal corresponding to a component having a second frequency or higher among the electrical signals converted by the microphone; A setting unit that sets either the first filter or the second filter; an amplifier that amplifies the electrical signal that has passed through the filter set by the setting unit; 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.

2. A conference support system that supports a conference by collecting speech from conference participants, playing the collected speech through a speaker, and presenting the speech to the conference participants, A microphone that converts an input audio signal into an electrical signal; an amplifier for amplifying the electrical signal converted by the microphone; a first tweeter that reproduces only an electrical signal corresponding to a component having a first frequency or higher among the electrical signals amplified by the amplifier; a second tweeter that reproduces only an electrical signal corresponding to a component having a second frequency or higher among the electrical signals amplified by the amplifier; A setting unit that sets either the first tweeter or the second tweeter; a parabolic surface formed on a part of a ceiling that reflects sound reproduced by the tweeter set by the setting unit.

3. A conference support system that supports a conference by collecting speech from conference participants, playing the collected speech through a speaker, and presenting the speech to the conference participants, A microphone that converts an input audio signal into an electrical signal; an equalizer that adjusts the amount of amplification for each frequency band of the electrical signal converted by the microphone; a setting unit that sets whether to increase an amount of amplification of a frequency band equal to or higher than a first frequency or to increase an amount of amplification of a frequency band equal to or higher than a second frequency by the equalizer; an amplifier that amplifies the electrical signal that has passed through the equalizer; 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.

4. 4. The conference support system according to claim 1, wherein the first frequency is 1 kHz.

5. 4. The conference support system according to claim 1, wherein the second frequency is a lower limit frequency of a 1 / 3 octave band having a center frequency of 2.5 kHz.

6. 6. The conference support system according to claim 1, further comprising a sound insulating panel disposed below said speaker.

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