JP4929703B2 - Sound emission and collection device - Google Patents

Abstract

It is possible to provide a sound emission and collection device having a compact configuration and capable of suppressing sound coming from a speaker to a microphone and improving the S/N ratio. In the sound emission and collection device, a plurality of speakers (11) have a sound emission surface arranged at the side surface of a case (1) so that a sound can be emitted in all the circumferential direction of the sound emission and collection device. Each of the microphones (12) is arranged with the sound collection direction set in the center direction of the case (1). The microphone (12) and the speaker (11) have directivities opposing to each other. Accordingly, it is possible to minimize the sound coming from the speaker (11) to the microphone (12). Moreover, since the speaker (11) and the microphone (12) are arranged on coaxial circumferences, it is possible to obtain a compact configuration.

Description

  The present invention relates to a sound emission and collection device that is integrally provided with a speaker and a microphone, and more particularly, to a sound emission and collection device that suppresses the sound that circulates from the speaker to the microphone while having a compact configuration.

  In order to conduct a voice conference (communication conference) in a remote place, a voice conference device that is integrally provided with a speaker and a microphone has become widespread. The audio conference apparatus transmits the sound collected by the microphone to the connection destination and emits the sound received from the connection destination from the speaker. When a conference is held among a plurality of people, such an audio conference apparatus is often installed at the center of a conference participant (the center of a conference desk or the like). Therefore, it is desired that such an audio conference apparatus be miniaturized. For example, as shown in Patent Document 1, a miniaturized audio conference apparatus that omits a speaker box has been proposed.

In addition, since the audio conference apparatus includes a speaker and a microphone in the same space, if the audio received from the connection destination is emitted from the speaker, the audio is collected by the microphone and transmitted to the connection destination. Noise such as echo is generated. Therefore, as shown in Patent Document 2, an audio conference apparatus having an echo canceller function has been proposed in which a microphone is accommodated at the tip of a cylindrical elastic body and acoustic coupling between the speaker and the microphone is suppressed. Yes.
JP-A-8-204803 JP-A-8-298696

  According to the configuration of Patent Document 1, although the configuration is compact, the speaker and the microphone are close to each other, and the wraparound volume is increased. On the other hand, according to the configuration of Patent Document 2, wraparound sound can be suppressed by the echo canceller function. Moreover, in patent document 2, it is the structure which suppresses the acoustic coupling inside a housing | casing with an elastic body.

  However, even if the acoustic coupling inside the housing can be suppressed, there is still a problem that the speaker and the microphone are close to each other due to the compact configuration, and the sound emitted from the speaker tends to wrap around the microphone. It was. In this case, a processing burden is imposed on the echo canceller function.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sound emitting and collecting apparatus that has a compact configuration and suppresses sound that circulates from a speaker to a microphone and has an improved S / N ratio.

The sound emission and collection device of the present invention includes a plurality of directional microphones arranged toward the center on a first circumference centered on one axis, and a second circle centered on the axis. A plurality of speakers arranged on the circumference in a direction opposite to the center;
Directional microphones with neighboring speaker, the sound collection direction of the sound output direction and the directional microphone of the speaker becomes opposite direction, the directional microphones farthest speaker together, sound direction and the directivity of the speaker It is characterized in that the sound collecting direction of the directional microphone is the same.

  In the present invention, a plurality of microphones and speakers are respectively installed on a circumference around the same axis. The directivity of the microphone and the speaker is installed in opposite directions. Therefore, it is possible to suppress the sound that goes around from the speaker to the microphone. Since both the speaker and the microphone are installed on the circumference with the same axis as the center, the structure is compact.

The present invention is further characterized in that the first circumference has a smaller diameter than the second circumference.

  The present invention further includes a casing in which the plurality of directional microphones and the plurality of speakers are arranged, the plurality of microphones being arranged on an upper surface of the casing, and the plurality of speakers in the casing It is arrange | positioned at the side surface side of this.

  The present invention further includes signal processing means for estimating the sound source direction based on the level of the audio signal collected by each microphone and outputting the audio signal collected by the microphone facing the sound source direction to the subsequent stage. It is characterized by that.

  In the present invention, a signal having the highest sound pressure level among the sound signals collected by each microphone is selectively output. Thereby, the S / N ratio can be further improved.

  In the present invention, the signal processing means further estimates a sound source direction by adding audio signals collected by a plurality of adjacent microphones, and adds a signal obtained by adding the audio signals collected by the plurality of adjacent microphones. It is characterized by being output to.

  In this invention, in each microphone, the audio signal collected from the adjacent microphone is added. Further, a signal having the highest sound pressure level is selectively output among these added audio signals. Thereby, the S / N ratio can be further improved.

  According to the present invention, a plurality of microphones and speakers are installed on the circumference of a concentric circle in a direction in which the sound collection direction and the sound emission direction are opposite to each other. , The S / N ratio can be improved.

  With reference to the drawings, a sound emission and collection device according to an embodiment of the present invention will be described. FIG. 1 is a top view of a sound emission and collection device according to this embodiment, and FIG. 2A is a cross-sectional view taken along line AA in FIG. In FIG. 1, the right side of the drawing is the X direction, the left side is the -X direction, the upper side is the Y direction, and the lower side is the -Y direction. In FIG. 2A, the right side of the drawing is the X direction, the left side is the -X direction, the upper side is the Z direction, and the lower side is the -Z direction.

  This sound emission and collection device is composed of a cylindrical housing 1, and a plurality (four in this example) of speakers 11A to 11D arranged concentrically on the outermost peripheral portion of the housing 1; A plurality of (eight in this example) microphones 12 </ b> A to 12 </ b> H arranged at equal intervals on a concentric circle are provided inside the housing 1. The microphones 12A to 12H are connected to the front-end amplifiers 13A to 13H (see FIG. 3), and output audio signals based on the collected sounds. The speakers 11A to 11D are connected to the amplifiers 19A to 19D (see FIG. 3), and emit sound based on the input sound signals.

  The casing 1 has a compact cylindrical shape with a diameter of a cross-sectional circle of about 30 cm as viewed from above, and has a height that allows the sound emitting surface of the speaker 11 to be arranged on the side surface of the cylinder (for example, about 10 cm).

  Each speaker 11 uses a cone-type speaker unit, a horn-type speaker unit, or the like, but may have other types. Each microphone 12 is a directional microphone having strong sensitivity in a predetermined direction. As the microphone 12, a dynamic microphone unit, a condenser microphone unit, or the like is used, but other types may be used.

  Each speaker 11 is installed on the side surface of the housing 1 such that the sound emission direction is outside the housing 1, and the four speakers 11 emit sound in different directions. For example, as illustrated in FIG. 2, the speaker 11 </ b> B emits sound in the X direction, and the speaker 11 </ b> D emits sound in the −X direction. Therefore, each speaker 11 can emit sound in the entire circumferential direction (X, -X, Y, -Y directions) of the sound emission and collection device.

  Each microphone 12 has a sound collection direction (a direction having strong sensitivity) in a central direction when viewed from the top surface of the housing 1 (for example, the sound collection direction of the microphone 12C is the -X direction and the sound collection direction of the microphone 12G is the X direction). It is installed in the upper surface of the housing | casing 1 so that it may become. The sound collection direction of each microphone 12 is the central direction of the housing 1, but since the plurality of microphones 12 are installed facing each other, the respective microphones 12 are arranged in the entire circumferential direction (eight directions) of the sound emission and collection device. ) Can be picked up.

  The sound emission direction and sound collection direction of the adjacent speaker 11 and microphone 12 (for example, the speaker 11B and microphone 12C) are substantially opposite directions. Further, the speaker 11 and the microphone 12 (for example, the speaker 11B and the microphone 12G) whose sound emission and sound collection directions are the same direction are arranged at positions farthest from each other in the housing 1. Accordingly, the sound that circulates from the speaker 11 to the microphone 12 becomes extremely small, and is smaller than that of a general sound emitting and collecting device (for example, when the speaker emitting surface is on the upper side of the housing and the microphone sound collecting surface is on the outer side of the housing). / N ratio is improved.

  Next, the configuration of the signal processing system of the sound emission and collection device will be described in detail with reference to FIG. FIG. 3 is a block diagram showing the configuration of the sound emission and collection device. The sound emission and collection device is connected to the above-described speaker 11A to speaker 11D, microphone 12A to microphone 12H, front-end amplifier 13A to amplifier 13H connected to each microphone 12A to microphone 12H, and each amplifier 13A to amplifier 13H. A / D converter 14A to A / D converter 14H, a microphone signal processing circuit 15 to which each A / D converter 14A to A / D converter 14H is connected, and an echo canceller 16 connected to the microphone signal processing circuit 15 The input / output interface 17 connected to the echo canceller 16, the D / A converters 18A to 18D connected to the echo canceller 16, and the D / A converters 18A to 18D connected to the D / A converters 18D. An amplifier 19 for supplying audio signals to the speakers 11A to 11D It has a, and - amplifier 19D.

  The audio signals output from the microphones 12A to 12H are amplified by the front-end amplifiers 13A to 13H, and digitally converted by the A / D converters 14A to 14H. The microphone signal processing circuit 15 selects and outputs the signal having the highest sound pressure level among the digital signals output from the A / D converters 14A to 14H.

  FIG. 4 shows a detailed block diagram of the microphone signal processing circuit 15. The microphone signal processing circuit 15 includes adders 151A to 151H, a select / mixing circuit 152, and a maximum signal strength detection circuit 153. Digital signals A to H are input to the adders 151A to 151H from the A / D converters 14A to 14H, respectively. Further, each adder 151 receives a signal adjacent to the signal input to each adder 151 (a microphone corresponding to each adder and a signal output from an adjacent microphone are adjacent). For example, a digital signal A and a digital signal B are input to the adder 151A, and a digital signal B and a digital signal C are input to the adder 151B. Each adder 151 adds the input digital signals and outputs the result. By adding the signals of adjacent microphones, the signal in the front direction of the microphone is strengthened, and the signals in the other directions are weakened, so that the directivity of the microphone is improved.

  Each of the added digital signals is compared with the sound pressure level in the maximum signal intensity detection circuit 153. The maximum signal intensity detection circuit 153 compares the sound pressure levels of the respective digital signals, and as a result, selects the digital signal having the highest sound pressure level and sets it in the select / mixing circuit 152. The select / mixing circuit 152 selects only the set digital signal and outputs it to the echo canceller 16. Further, the maximum signal strength detection circuit 153 may select a plurality of digital signals in order from the digital signal having the highest sound pressure level and set the selected signal in the select / mixing circuit 152. In this case, the select / mixing circuit 152 mixes a plurality of set digital signals and outputs them to the echo canceller 16.

  A signal with the highest sound pressure level or a signal in which a plurality of signals are mixed in order from the signal with the highest sound pressure level is output, and other signals with lower levels are not output. improves. In the above configuration, the signals of the adjacent microphones 12 are added and output. However, the signals collected by the microphones 12 may be output individually, or two or more adjacent signals may be added. May be output.

  The output signal of the microphone signal processing circuit 15 is input to the echo canceller 16. The output signal of the echo canceller 16 is transmitted to another device via the input / output interface 17. The input / output interface 17 has a LAN terminal, an analog audio terminal, a digital audio terminal, and the like, and transmits the signal to a device connected to these terminals. When outputting to the LAN terminal, it is transmitted as audio information to a remote device connected via the network. Further, the input / output interface 17 outputs audio information (received signal) received from another device to the echo canceller 16. The echo canceller 16 estimates a sneak component from the speaker 11 to the microphone 12 and subtracts the estimated sneak component from the output signal of the microphone signal processing circuit 15.

  FIG. 5 shows a detailed block diagram of the echo canceller 16. The echo canceller 16 includes an adaptive filter 161 and an adder 162. The adaptive filter 161 includes a digital filter such as an FIR filter. The adaptive filter 161 estimates the transfer function of the acoustic transfer system (the acoustic propagation path from the speaker 11 to the microphone 12), and calculates the filter coefficient of the FIR filter so as to simulate the estimated transfer function. The adaptive filter 161 generates a simulation signal of a wraparound component from the speaker 11 to the microphone 12 with the estimated filter coefficient. This simulated signal is subtracted from the output signal of the microphone signal processing circuit 15 in the adder 162. Therefore, the output signal of the adder 162 is a signal obtained by removing the wraparound component from the sound collection signal of the microphone 12.

  The estimation of the transfer function and the calculation of the filter coefficient are performed using an adaptive algorithm based on the signal supplied to the speaker 11 using the residual signal, which is the signal output from the adder 162, as a reference signal. The adaptive algorithm is an algorithm that calculates filter coefficients so that the residual signal is as small as possible.

  As a result, a signal simulating the sneak signal of the acoustic transmission system (audio signal from the speaker 11 to the microphone 12) is generated in the adaptive filter 161, and only the sneak signal is obtained by subtracting the simulated signal from the collected sound signal in the adder 162. Can be efficiently attenuated. Thereby, the echo canceller 16 can prevent an echo generated by the sneak signal. When this sound emitting and collecting device is used as a loudspeaker that emits sound collected by the microphone 12 from the speaker 11 via the input / output interface 17, the echo canceller 16 performs howling caused by a loop phenomenon of a wraparound signal. It can also be prevented.

  An output signal (received signal from another device) of the echo canceller 16 is output to each of the D / A converter 18A to D / A converter 18D and converted into an analog audio signal. These analog audio signals are amplified by the amplifiers 19A to 19D and emitted from the speakers 11A to 11D.

  The configuration of the microphone signal processing circuit 15 is not limited to the above example. FIG. 6 shows a configuration of an application example of the microphone signal processing circuit 15. In this example, signals A to H are input to delays 154A to 154H, delays 155A to 155H, and delays 156A to 156H, respectively. Output signals of delays 154A to 154H are input to adders 157A to 157H, respectively. Further, the output signals of the delays 155A to 155H are input to the adders 157A to 157H while being shifted to the adjacent adders 157. That is, the output signal of the delay 155B is to the adder 157A, the output signal of the delay 155C is to the adder 157B, the output signal of the delay 155D is to the adder 157C, and so on. The output signal and the output signal of the adjacent microphone 12 are added.

  Further, the output signals of the delays 156A to 156H are further shifted by one stage to the adders 157A to 157H. That is, the output signal of the delay 156C is to the adder 157A, the output signal of the delay 156D is to the adder 157B, the output signal of the delay 156E is to the adder 157C, and so on. The output signal and the output signal of the microphones 12 on both sides are added.

  Each of the delays 154, 155, and 156 gives a delay time to the input audio signal so that the three signals added in the adder 157 have the same phase. Therefore, the sound collected by the microphones 12 is added in the same phase to the sound collected signals of the two adjacent microphones 12 in the corresponding adders 157, respectively. Since the signals are added in the same phase, the signal in a specific direction is strengthened, and the S / N ratio is improved and the directivity is improved. Of course, the number of signals to be added is not limited to three as described above, and the S / N ratio in a predetermined direction can be improved by adding or subtracting a plurality of signals.

  The structure of the sound emission and collection device of the present invention and the number of speakers 11 and microphones 12 are not limited to the examples shown in FIG. 1 and FIG.

(Modification of the housing 1)
For example, as illustrated in FIG. 2B, a dome-shaped (hemispherical) cover 122 having a bulge in the Z direction may be attached to the upper surface of the housing 1. The cover 122 has a size that covers all of the plurality of microphones 12 installed on the upper surface of the housing 1. The cover 122 is made of a punched mesh steel plate and does not interfere with the sound collection of the microphone 12 installed on the upper surface of the housing 1.

  Even in the state shown in FIG. 2B, the sound emission direction and sound collection direction of the adjacent speaker 11 and microphone 12 (for example, the speaker 11B and microphone 12C) are substantially opposite directions. Further, the speaker 11 and the microphone 12 (for example, the speaker 11B and the microphone 12G) whose sound emission and sound collection directions are the same direction are arranged at positions farthest from each other in the housing 1. Therefore, also in the example of FIG. 2B, the sound that circulates from the speaker 11 to the microphone 12 becomes extremely small, and the S / N ratio is improved.

(Other Example 1)
FIG. 7 shows the structure of a sound emission and collection device in another example. FIG. 7 is a top view and a cross-sectional view showing another example of the sound emission and collection device. FIG. 2A is a top view of the sound emission and collection device, and FIG. 2B is a cross-sectional view taken along the line A-A in FIG. In FIG. 3A, the right side of the drawing is the X direction, the left side is the -X direction, the upper side is the Y direction, and the lower side is the -Y direction. In FIG. 4B, the right side of the drawing is the X direction, the left side is the -X direction, the upper side is the Z direction, and the lower side is the -Z direction. In addition, about the component which is common in the sound emission and collection apparatus shown in FIG. 1 and FIG. 2, the same code | symbol is attached | subjected and the description is abbreviate | omitted.

  The sound emission and collection device in this example includes a cylindrical housing 2, and a plurality (four in this example) of speakers 11A to 11D arranged concentrically on the outermost peripheral portion of the housing 2 at equal intervals. And a plurality (eight in this example) of microphones 12 </ b> A to 12 </ b> H arranged on the upper surface of the housing 2 at equal intervals on a concentric circle.

  The casing 2 has a compact columnar shape with a diameter of a cross-sectional circle of about 30 cm viewed from the top surface, and has a height that allows the sound emitting surface of the speaker 11 to be disposed on the side surface of the column (for example, about 10 cm). The housing 2 has a trapezoidal bulge in the Z direction near the center of the upper surface. The microphone 12 is installed in the upper part of this bulging surface. The bulging surface has a flat central portion so as not to disturb the sound collection of the microphone 12.

  Each speaker 11 is installed such that the sound emission direction is outside the housing 2. Each microphone 12 is installed such that the sound collection direction is the center direction when viewed from the top surface of the housing 2 (for example, the sound collection direction of the microphone 12C is the -X direction and the sound collection direction of the microphone 12G is the X direction). . Since each microphone 12 is installed so as to ride on the upper surface of the housing 2, sound inside the housing 2 (sound emitted by the speaker 11 in the housing 2) is not collected.

  Each speaker 11 and each microphone 12 are installed at different heights, but the sound emission direction and sound collection direction of the adjacent speaker 11 and microphone 12 (for example, speaker 11B and microphone 12C) are substantially opposite directions. . Further, the speaker 11 and the microphone 12 (for example, the speaker 11B and the microphone 12G) whose sound emission and sound collection directions are the same direction are arranged at positions farthest from each other in the housing 2. Therefore, also in this example, the sound that circulates from the speaker 11 to the microphone 12 becomes extremely small, and the S / N ratio compared to a general sound emitting and collecting device (for example, the speaker emitting surface is on the upper side and the microphone sound collecting surface is on the outer side). Will improve.

(Other Example 2)
Further, the sound emission and collection device may have a structure as shown in FIG. FIG. 8 is a top view and a cross-sectional view showing another example of the sound emission and collection device. FIG. 2A is a top view of the sound emission and collection device, and FIG. 2B is a cross-sectional view taken along the line A-A in FIG. In FIG. 3A, the right side of the drawing is the X direction, the left side is the -X direction, the upper side is the Y direction, and the lower side is the -Y direction. In FIG. 4B, the right side of the drawing is the X direction, the left side is the -X direction, the upper side is the Z direction, and the lower side is the -Z direction. In this example as well, components common to the sound emitting and collecting apparatus shown in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

  The sound emission and collection device in the example of the figure is composed of a casing 3 having a structure in which a plurality of cylindrical casings (upper casing 3A and lower casing 3B) are vertically stacked. A plurality of microphones 12A to 12H arranged concentrically on the upper surface of the outermost peripheral part, and a plurality of speakers 11A to 11D arranged concentrically on the outermost peripheral part of the lower housing 3B. It is equipped with.

  The upper housing 3A and the lower housing 3B are joined such that the center of the bottom surface is on the same axis, and the upper housing 3A has a larger volume than the lower housing 3B, and the upper housing 3A The side surface is the outer peripheral side, and the side surface of the lower housing 3B is the inner peripheral side.

  Each speaker 11 is installed such that the sound emission direction is outside the housing 3. Each microphone 12 is installed such that the sound collection direction is the center direction when viewed from the top surface of the housing 3 (for example, the sound collection direction of the microphone 12C is the -X direction and the sound collection direction of the microphone 12G is the X direction). . Since each microphone 12 is installed so as to ride on the upper surface of the housing 3, sound inside the housing 3 (sound emitted by the speaker 11 in the housing 3) is not collected.

  Thus, even when each speaker 11 is arranged on the inner circumference of the concentric circle and each microphone 12 is arranged on the outer circumference side when viewed from the upper side of the housing, the adjacent speakers 11 and microphones 12 (for example, the speaker 11B and the microphone 12C) are released. The sound direction and the sound collection direction are substantially opposite directions. Further, the speaker 11 and the microphone 12 (for example, the speaker 11B and the microphone 12G) whose sound emission and sound collection directions are the same are arranged at positions farthest from each other in the housing 3. Therefore, also in the example of FIG. 8, the sound that circulates from the speaker 11 to the microphone 12 becomes extremely small, and the S / N ratio is improved.

(Other Example 3)
FIG. 9 is a top view and a cross-sectional view showing still another example of the sound emission and collection device. FIG. 2A is a top view of the sound emission and collection device, and FIG. 2B is a cross-sectional view taken along the line A-A in FIG. In FIG. 3A, the right side of the drawing is the X direction, the left side is the -X direction, the upper side is the Y direction, and the lower side is the -Y direction. In FIG. 4B, the right side of the drawing is the X direction, the left side is the -X direction, the upper side is the Z direction, and the lower side is the -Z direction. In this example as well, components common to the sound emitting and collecting apparatus shown in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

  The sound emission and collection device in this example is composed of a substantially cylindrical housing 4, and a plurality of (four in this example) speakers 11 </ b> A to 11 </ b> A arranged at equal intervals on the outermost peripheral portion of the housing 4. 11D and a plurality (eight in this example) of microphones 12A to 12H arranged concentrically on the inside of the housing 1.

  The casing 4 has a compact columnar shape with a diameter of a cross-sectional circle of about 30 cm as viewed from above, and has a height that allows the sound emitting surface of the speaker 11 to be disposed on the side surface of the column (for example, about 10 cm).

  Each speaker 11 is installed on each side so that the sound emission direction is outside the housing 4. Each microphone 12 is installed such that the sound collection direction is the center direction when viewed from the top surface of the housing 4 (for example, the sound collection direction of the microphone 12C is the -X direction and the sound collection direction of the microphone 12G is the X direction). . The housing 4 has a hemispherical recess in the vicinity of the center of the upper surface in the housing inner direction (−Z direction), and a plurality of holes are formed in a part of the recessed surface. Sealed boxes 121A to 121H are installed in the holes, and microphones 12A to 12H are embedded in the boxes 121A to 121H, respectively. The hole becomes the opening surface of the box 121, and the sound collecting surface of the microphone 12 is directed to the opening surface of the box 121. The box 121 is an elastic body such as rubber and blocks the propagation of sound emitted from the speaker 11 in the housing 4. The sound collecting direction of each microphone 12 is the central direction of the housing 4. However, since the plurality of microphones 12 are installed facing each other, the respective microphones 12 are arranged in the entire circumferential direction (eight directions) of the sound emitting and collecting device. ) Can be picked up.

  Each speaker 11 and each microphone 12 are installed at substantially the same height. Therefore, the sound emission direction and the sound collection direction of the adjacent speaker 11 and microphone 12 (for example, the speaker 11B and microphone 12C) are opposite directions. Further, the speaker 11 and the microphone 12 (for example, the speaker 11B and the microphone 12G) whose sound emission and sound collection directions are the same are arranged at positions farthest from each other in the housing 4. Accordingly, the sound that circulates from the speaker 11 to the microphone 12 becomes extremely small, and is smaller than that of a general sound emitting and collecting device (for example, when the speaker emitting surface is on the upper side of the housing and the microphone sound collecting surface is on the outer side of the housing). / N ratio is improved.

(Other Example 4)
FIG. 10 is a top view and a cross-sectional view showing still another example of the sound emission and collection device. FIG. 2A is a top view of the sound emission and collection device, and FIG. 2B is a cross-sectional view taken along the line A-A in FIG. In FIG. 3A, the right side of the drawing is the X direction, the left side is the -X direction, the upper side is the Y direction, and the lower side is the -Y direction. In FIG. 4B, the right side of the drawing is the X direction, the left side is the -X direction, the upper side is the Z direction, and the lower side is the -Z direction. In this example as well, components common to the sound emitting and collecting apparatus shown in FIGS. 1 and 2 are denoted by the same reference numerals, and description thereof is omitted.

  The sound emission and collection device in this example includes a substantially rectangular parallelepiped housing 5, a speaker 11 </ b> A installed on the Y side surface of the housing 5, a speaker 11 </ b> B installed on the X side surface, and a speaker 11 </ b> C installed on the −Y side surface. , -X It has the speaker 11D installed in the side surface. Also, a microphone 12B installed in the direction of X, Y45 degrees inside the housing 5, a microphone 12D installed in the direction of X, -Y45 degrees, a microphone 12F installed in the directions of -X, -Y45 degrees,- A microphone 12H installed in directions of X and Y 45 degrees is provided.

  The housing 5 has a square cross-sectional shape with a side length of about 30 cm when viewed from above, and has a height that allows the sound emitting surface of the speaker 11 to be disposed on the side of the rectangular parallelepiped (for example, about 10 cm).

  Each speaker 11 is installed on each side so that the sound emission direction is outside the housing 5. Each microphone 12 has a sound collection direction as viewed from the top surface of the housing 3 (for example, the sound collection direction of the microphone 12B is -X, -Y45 degrees, and the sound collection direction of the microphone 12H is X, -Y45 degrees). Direction). The housing 5 has a hemispherical recess in the vicinity of the center of the upper surface in the housing interior direction (−Z direction), and a part of the recessed surface is exposed to the inside (by a punch mesh or the like), and the sound collection of the microphone 12 is performed. The surface is peeking. Further, the microphones 12B to 12H are fitted in sealed boxes 121B to 121H installed inside the casing of the exposed surface, respectively. The box 121 is an elastic body such as rubber and blocks the propagation of sound emitted from the speaker 11 in the housing 5.

  Also in the sound emitting and collecting apparatus in this example, as shown in FIG. 2B, the microphones 12B to 12H may be installed on the upper surface of the housing 5 and a hemispherical cover may be attached.

  Thus, the shape of the housing is not limited to a cylinder, and may be a rectangular parallelepiped shape. The number of microphones and speakers is not limited to the above example. Furthermore, in the sound emitting and collecting apparatus shown in FIG. 10, an example in which the number of microphones is four is shown, but a plurality of microphones can be virtually installed. FIG. 11 is a block diagram showing a configuration of the microphone signal processing circuit 15 of the sound emission and collection device in FIG. The signals B to H output from the microphones 12B to 12H are input to the select / mixing circuit 152, but each signal is branched and input to a plurality of delays 158. For example, the signal B is branched and input to the delay 158B1 and the delay 158B2. Similarly, the signal D is branched and input to the delays 158D1 and 158D2, the signal F is branched and input to the delays 158F1 and 158F2, and the signal H is branched and input to the delays 158H1 and 158H2.

  Output signals of the delay 158B2 and the delay 158D1 are input to the adder 159C. Similarly, the output signals of delay 158D2 and delay 158F1 are input to adder 159E, the output signals of delay 158F2 and delay 158H1 are input to adder 159G, and the output signals of delay 158H2 and delay 158B1 are adders 159A. Is input.

  In each adder 159, the two signals of the adjacent microphones 12 are added after being given a delay time in the delay 158, so that the output signal of each adder 159 is stored at a position between the microphones 12. Corresponds to the sound that was heard For example, when the delay time of the signal B in the delay 158B1 is equal to the delay time of the signal H in the delay 158H2, the signal A added by the adder 159A is output between the microphone 12B and the microphone 12H as shown in FIG. This is the same as the sound collected by the microphones installed at the same distance. That is, the signal A shown in FIG. 11 represents the output signal of the virtual microphone 32A of FIG. Similarly, the signal C shown in FIG. 11 represents the output signal of the virtual microphone 32C, the signal E represents the output signal of the virtual microphone 32E, and the signal G represents the output signal of the virtual microphone 32G. Therefore, in this example, four microphones 12 can pick up sounds in eight directions.

Top view of sound emission and collection device AA sectional view of FIG. 1 and AA sectional view of a modification of the housing 1 Block diagram of sound emission and collection equipment Detailed block diagram of microphone signal processing circuit Detailed block diagram of echo canceller Detailed block diagram of application example of microphone signal processing circuit The top view of A sound emission and collection apparatus in other Example 1, and AA sectional drawing The top view of A sound emission and collection apparatus in other Example 2, and AA sectional drawing The top view of A sound emission and collection apparatus in other Example 3, and AA sectional drawing The top view of A sound emission and collection apparatus in other Example 4, and AA sectional drawing Block diagram of microphone signal processing circuit Illustration showing the concept of a virtual microphone

Explanation of symbols

1-housing 11-speaker 12-microphone 13-amplifier 14-A / D converter 15-microphone signal processing circuit 16-echo canceller 17-input / output interface 18-D / A converter 19-amplifier

Claims (5)

A plurality of directional microphones arranged toward the center on a first circumference centered on one axis;
A plurality of speakers disposed on a second circumference centered on the axis and in a direction opposite to the center;
With
Directional microphones with neighboring speaker, the sound collection direction of the sound output direction and the directional microphone of the speaker becomes opposite direction, the directional microphones farthest speaker together, sound direction and the directivity of the speaker A sound emission and collection device in which the sound collection direction of the directional microphone is the same.   2. The sound emission and collection device according to claim 1, wherein the first circumference has a diameter smaller than that of the second circumference. A housing for arranging the plurality of directional microphones and the plurality of speakers;
The plurality of microphones are arranged on an upper surface of the housing,
The sound emission and collection device according to claim 1, wherein the plurality of speakers are arranged on a side surface side of the housing.   2. A signal processing means for estimating a sound source direction based on a level of a sound signal picked up by each microphone, and outputting a sound signal picked up by a microphone facing the sound source direction to a subsequent stage. The sound emission and collection device according to claim 2 or claim 3.   5. The signal processing means adds a sound signal picked up by a plurality of adjacent microphones to estimate a sound source direction, and outputs a signal obtained by adding the sound signals picked up by a plurality of adjacent microphones to a subsequent stage. The sound emission and collection device described in 1.

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