Sound field control apparatus

Abstract

To realize a sound field control system that solves an occlusion problem and applies proper sound field control to a plurality of local sound fields even when a sound wave advancing direction is any direction.SOLUTION: In the sound field control system 1000, a plurality of local sound fields are decomposed into one global internal sound field and one global external sound field and optimized, and the decomposed and optimized global internal sound field and global external sound field can be simultaneously reproduced by using the internal-sound-field speaker array and the external-sound-field speaker array. Therefore, in the sound field control system 1000, it is possible to solve the occlusion problem and perform appropriate sound field control on a plurality of local sound fields regardless of the sound wave traveling direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a multi-sound field control technology that simultaneously realizes different sound fields in multiple different areas. [Background technology]

[0002] In recent years, technologies for multi-sound field control have been developed. Multi-sound field control is a control method for simultaneously realizing multiple different sound fields (local sound fields), including sound fields in silent regions, in multiple locations using a speaker array. It can be broadly divided into sound pressure control methods (see, for example, Non-Patent Document 1) and mode control methods (see, for example, Non-Patent Documents 2 and 3).

[0003] Both the sound pressure control method and the modal control method are methods for reproducing wavefronts in all directions in a local sound field, and therefore the speaker array is arranged to surround all local sound fields, such as a circle (for example, the speaker array is arranged in a circle so as to surround all local sound fields (see, for example, Figure 25 (a diagram schematically showing speaker arrays Spk_int.1 to Spk_int.16 arranged in a circle so as to surround all local sound fields))). In the sound pressure control method, the sound pressure at multiple points within multiple local sound fields is controlled by drive signals (signals for driving each speaker) calculated using the inverse matrix of the transfer function between the control point and each speaker. On the other hand, in the modal control method, multiple local sound fields are converted into a cylindrical-spherical harmonic spectrum (or spherical harmonic spectrum) of a single global incoming sound field by inverse calculation of a Bessel function or the shift theorem of spherical harmonic functions, and sound field control using the modal control method is realized by executing a modal control type sound field control method. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] M. Poletti, "An investigation of 2D multizone surround sound systems," in Proc. 125th Conv. Audio Eng. Soc., Oct. 2008. [Non-patent document 2] YJ Wu and TD Abhayapala, "Spatial multizone sound field reproduction: Theory and design," IEEE Trans. Audio, Speech, Lang. Process., vol. 19, no. 6, pp. 1711 1720, Aug. 2011. [Non-patent document 3] W. Zhang, TD Abhayapala, T. Betlehem, and FM Fazi, "Analysis and control of multi zone sound field reproduction using modal domain approach," J. Acoust. Soc. Am., vol. 140, no. 3, pp. 2134 2144, Sept. 2016. Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional sound field control techniques that use speakers arranged to surround a global sound arrival field, such as a circular speaker array, have the following major problem. When local sound field 1 is assumed to be a silent region and sound wavefronts of sound waves in all directions are reproduced in local sound field 2, the reproduction accuracy of the sound wave front strongly depends on the direction of travel of the sound wave front in the position of local sound field 1 and local sound field 2. Furthermore, when the direction of travel of the sound wave front is parallel to local sound field 1 (when the vector indicating the direction of travel of the sound wave front is parallel to the position vector from a reference point (for example, the center point of the global sound arrival field (for example, the center point of the global sound arrival field (circular region) in Figure 25)) to the position of local sound field 1 (for example, the center point of local sound field 1)), an "occlusion problem" occurs, which significantly deteriorates the control performance of the sound field control. This is because it is fundamentally impossible to represent multiple local sound fields in a single global sound arrival field. This "occlusion problem" (the problem of occlusion occurring) occurs not only in the mode control method but also in the sound pressure control method.

[0006] In view of the above problems, the present invention aims to realize a sound field control device, a sound field control system, a sound field control method, and a program that solve the occlusion problem (without causing the occlusion problem) and perform appropriate sound field control on multiple local sound fields regardless of the direction of sound wave propagation. [Means for solving the problem]

[0007] The first invention for solving the above problem is a sound field control device that performs sound field control for multiple local sound field areas set in an area surrounded by a speaker array for an internal sound field and a speaker array for an external sound field, and includes a local sound field setting unit, a local sound field decomposition optimization processing unit, and a global sound field simultaneous reproduction processing unit.

[0008] The local sound field setting unit sets a local sound field for each of the plurality of local sound field regions, thereby setting a plurality of local sound fields.

[0009] The local sound field decomposition optimization processing unit performs processing to decompose and optimize a plurality of local sound fields into (1) one global internal sound field and (2) one global external sound field.

[0010] The global sound field simultaneous reproduction processing unit performs a sound field simultaneous reproduction process, which is a process of simultaneously reproducing the global internal sound field and global external sound field decomposed and optimized by the local sound field decomposition optimization processing unit using a speaker array for the internal sound field and a speaker array for the external sound field.

[0011] This sound field control device decomposes and optimizes multiple local sound fields into (1) one global internal sound field and (2) one global external sound field, and can simultaneously reproduce the decomposed and optimized global internal sound field and global external sound field using a speaker array for the internal sound field and a speaker array for the external sound field. Therefore, this sound field control device can solve the occlusion problem (without causing the occlusion problem) and perform appropriate sound field control for multiple local sound fields regardless of the direction of sound wave propagation.

[0012] The second invention is the first invention, in which all of the speakers constituting the external sound field speaker array are installed on the surface of a baffle that does not allow sound waves to travel inside it.

[0013] The global sound field simultaneous reproduction processor performs the sound field simultaneous reproduction process by driving the speaker array for the internal sound field and the speaker array for the external sound field using a driving function that takes the baffle into consideration.

[0014] In this sound field control device, a driving function that takes the baffle into consideration is used, so that the problem of forbidden frequencies can be resolved, and as a result, appropriate simultaneous sound field reproduction processing can be performed.

[0015] The third invention is the second invention, wherein the speakers that make up the speaker array for the internal sound field are arranged on a circle of a first radius in a planar view, and the speakers that make up the speaker array for the external sound field are arranged on a circle of a second radius that is smaller than the first radius in a planar view.

[0016] The baffle is cylindrical with a radius substantially equal to the second radius.

[0017] This allows the sound field control device to control the sound field by a mode control method using a two-dimensional cylindrical harmonic spectrum.

[0018] A fourth aspect of the present invention is any one of the first to third aspects of the present invention, wherein the plurality of local sound field regions are N (N: natural number) local sound field regions, and the local sound field of a k-th local sound field region (k: natural number, 1≦k≦N) included in the N local sound field regions is defined as the k-th local sound field, and the local sound field setting unit: (1) In a first local sound field region, a local sound field that reproduces the sound of the first language is set as a first local sound field; (2) In the m-th local sound field region (m: natural number, 2≦m≦N), a local sound field that reproduces the sound of a language other than the first language is set as the m-th local sound field.

[0019] This makes it possible to reproduce (reproduce) sounds in different languages ​​in a plurality of local sound fields, and therefore, by using this sound field control device, it is possible to realize, for example, a multilingual speech translation system.

[0020] A fifth invention is a sound field control system including an internal sound field speaker array, an external sound field speaker array, and the sound field control device according to any one of the first to fourth inventions.

[0021] This makes it possible to realize a sound field control system that provides the same effects as the sound field control device according to any one of the first to fourth aspects of the present invention.

[0022] A sixth aspect of the present invention is a sound field control device that performs sound field control using a weighted mode control method that takes into account mutual diffusion between the speakers and the baffles in an area that includes one or more speakers and one or more baffles, and includes a sound field setting processing unit, a transfer function matrix setting processing unit, a multiple diffusion component data acquisition processing unit, and a sound field reproduction processing unit.

[0023] The sound field setting processing unit sets one or more sound field control target regions.

[0024] The transfer function matrix setting processing unit (1) sets a first transfer function matrix, which is a matrix of transfer functions between baffles taking into account mutual diffusion, and (2) sets a second transfer function matrix, which is a matrix of transfer functions between speakers and baffles taking into account diffusion by the speakers.

[0025] The multiple diffused component data acquisition processing unit performs a process of setting a matrix that takes multiple diffusion into consideration using the first transfer function matrix and the second transfer function matrix, and acquires multiple diffused component data from the matrix acquired by the setting process.

[0026] The sound field reproduction processing unit acquires a third transfer function, which is a transfer function between the speaker and the control target area, based on the multiple diffuse component data, and acquires a drive signal for driving each of one or more speakers using a weighted mode control method based on the acquired third transfer function.

[0027] As described above, this sound field control device performs sound field control using the weighted mode control method that takes mutual diffusion into consideration, and therefore can accurately realize (reproduce) a desired sound field in any region (control target area).

[0028] Furthermore, this sound field control device solves the occlusion problem (without causing the occlusion problem) and can appropriately control the sound field in the area to be controlled, regardless of the direction of sound wave propagation.

[0029] The seventh invention is a sound field control method for performing sound field control for multiple local sound field areas set in an area surrounded by a speaker array for an internal sound field and a speaker array for an external sound field, and includes a local sound field setting step, a local sound field decomposition optimization processing step, and a global sound field simultaneous reproduction processing step.

[0030] The local sound field setting step sets a local sound field for each of the plurality of local sound field regions, thereby setting a plurality of local sound fields.

[0031] The local sound field decomposition and optimization processing step performs processing to decompose and optimize a plurality of local sound fields into (1) one global internal sound field and (2) one global external sound field.

[0032] The global sound field simultaneous reproduction processing step performs a sound field simultaneous reproduction process in which the global internal sound field and the global external sound field decomposed and optimized by the local sound field decomposition optimization processing step are simultaneously reproduced using a speaker array for the internal sound field and a speaker array for the external sound field.

[0033] This makes it possible to realize a sound field control method that has the same effects as the first aspect of the invention.

[0034] The eighth invention is a sound field control method for performing sound field control using a weighted mode control method that takes into account mutual diffusion between the speakers and the baffles in an area including one or more speakers and one or more baffles, and includes a sound field setting processing step, a transfer function matrix setting processing step, a multiple diffusion component data acquisition processing step, and a sound field reproduction processing step.

[0035] The sound field setting processing step sets one or more sound field control target areas.

[0036] The transfer function matrix setting processing step (1) sets a first transfer function matrix, which is a matrix of transfer functions between baffles taking into account mutual diffusion, and (2) sets a second transfer function matrix, which is a matrix of transfer functions between speakers and baffles taking into account diffusion by the speakers.

[0037] The multiple diffusion component data acquisition processing step performs a process of setting a matrix that takes multiple diffusion into consideration using the first transfer function matrix and the second transfer function matrix, and acquires multiple diffusion component data from the matrix acquired by the setting process.

[0038] The sound field reproduction processing step acquires a third transfer function, which is a transfer function between the speaker and the control target area, based on the multiple diffuse component data, and acquires a drive signal for driving each of one or more speakers using a weighted mode control method based on the acquired third transfer function.

[0039] This makes it possible to realize a sound field control method that has the same effect as the sixth aspect of the invention.

[0040] A ninth aspect of the present invention is a program for causing a computer to execute the sound field control method of the seventh or eighth aspect of the present invention.

[0041] This makes it possible to realize a program for causing a computer to execute a sound field control method that has the same effects as the first or sixth invention. [Effects of the Invention]

[0042] According to the present invention, it is possible to realize a sound field control device, a sound field control system, a sound field control method and a program that solve the occlusion problem (without causing the occlusion problem) and perform appropriate sound field control on multiple local sound fields regardless of the direction of sound wave propagation. [Brief explanation of the drawings]

[0043] [Figure 1] 1 is a schematic configuration diagram of a sound field control system 1000 according to a first embodiment. [Figure 2] FIG. 1 is a schematic configuration diagram of a speaker array of a sound field control system 1000 according to a first embodiment. [Figure 3] 1 is a schematic configuration diagram of a speaker array of a sound field control system 1000 according to a first embodiment (a diagram showing a local sound field region). [Figure 4] 1 is a flowchart of a process executed by the sound field control system 1000. [Figure 5] A figure showing (a) the global internal sound field, (b) the global external sound field, and (c) the global internal / external mixed sound field when the present invention is applied by setting local sound field areas Zone(1) and Zone(2), setting the local sound field area Zone(1) as a silent area, and setting the local sound field area Zone(2) as a sound area. [Figure 6] 1 is a diagram showing the results of a comparison between a global internal synthesized sound field according to the prior art and a global internal and external mixed (synthesized) sound field according to the present invention. [Figure 7] 1 is a diagram showing the results of a comparison between a global internal synthesized sound field according to the prior art and a global internal and external mixed (synthesized) sound field according to the present invention. [Figure 8] A diagram (left) showing the relationship between the propagation direction of a plane wave and the synthesis error of the synthesized sound field according to the present invention and the conventional technology, and a diagram (right) showing the relationship between the propagation direction of a plane wave and the acoustic contrast of the synthesized sound field according to the present invention and the conventional technology. [Figure 9] FIG. 10 is a schematic diagram of a multilingual speech translation system 1000MT according to a first modified example of the first embodiment. [Figure 10] FIG. 10 is a diagram (viewed from above) schematically illustrating the recording state of the original sound field in a multilingual speech translation system 1000MT according to a first modified example of the first embodiment. [Figure 11] FIG. 10 is a diagram for explaining multilingual multi-sound field reproduction in the multilingual speech translation system 1000MT of the first modified example of the first embodiment (a diagram showing a local sound field region). [Figure 12] FIG. 10 is a schematic configuration diagram of a sound field control system 2000 according to a second embodiment. [Figure 13]FIG. 10 is a schematic configuration diagram (plan view seen from above) of a speaker array (one example) of a sound field control system 2000 according to a second embodiment. [Figure 14] FIG. 10 is a diagram schematically showing a baffle and a speaker array (one example) of a sound field control system 2000 according to a second embodiment. [Figure 15] A diagram (plan view from above) showing the layout of the baffle, speaker, and controlled area. [Figure 16] 1 is a flowchart of a process (sound field control process taking multiple diffusion into consideration) executed by the sound field control system 1000. [Figure 17] A schematic diagram of the experimental environment for Experiment 1. [Figure 18] A schematic diagram of the experimental environment for Experiment 1. [Figure 19] FIG. 1 shows the experimental results of Experiment 1 (when there is one control area). [Figure 20] FIG. 1 shows the experimental results (frequency-synthesis error characteristics) of Experiment 1. [Figure 21] A schematic diagram of the experimental environment for Experiment 2. [Figure 22] A schematic diagram of the experimental environment for Experiment 2. [Figure 23] 10 shows the experimental results of Experiment 2 (when there are two control areas). [Figure 24] A diagram showing the CPU bus configuration. [Figure 25] FIG. 1 is a schematic diagram of a speaker array of a conventional sound field control system. DETAILED DESCRIPTION OF THE INVENTION

[0044] [First embodiment] The first embodiment will be described below with reference to the drawings.

[0045] <1.1: Sound field control system configuration> FIG. 1 is a schematic diagram of a sound field control system 1000 according to the first embodiment.

[0046] FIG. 2 is a schematic diagram showing the configuration of a speaker array of the sound field control system 1000 according to the first embodiment.

[0047] FIG. 3 is a schematic configuration diagram of the speaker array of the sound field control system 1000 according to the first embodiment (a diagram showing a local sound field area).

[0048] As shown in Fig. 1, the sound field control system 1000 includes a sound field control device 100, a speaker array Spk_int for an arrival sound field (speaker array Spk_int for an internal sound field), and a speaker array Spk_ext for a radiation sound field (speaker array Spk_ext for an external sound field). For ease of explanation, the sound field control system 1000 includes a plurality of local sound field regions (Q regions Zone in Fig. 3) set within a region ROI_global surrounded by the speaker array Spk_int for an internal sound field (speaker array Spk_int for an arrival sound field), a cylindrical baffle Baf1, and a speaker array Spk_ext for an external sound field (speaker array Spk_ext for a radiation sound field) arranged on the cylindrical baffle Baf1, as shown in Figs. 2 and 3. (1) ~Zone (Q) The following explanation will be given assuming that the sound field of (Q: natural number) is controlled.

[0049] As shown in FIG. 1, the sound field control device 100 includes a local sound field setting unit 11, a local sound field decomposition processing unit 12, an optimization processing unit 13, and a global sound field simultaneous reproduction processing unit .

[0050] The local sound field setting unit 11 sets information about a plurality of local sound fields. For ease of explanation, the plurality of local sound fields are assumed to be Q (Q: natural number, Q≧2) local sound fields (Q local sound field regions Zone in FIG. 3 ). (1) ~Zone (Q) The case where the sound field is set as follows will be described.

[0051] The local sound field setting unit 11 sets information such as the position, size, direction of sound waves, whether or not it is a silent area, etc. for each of the Q local sound fields. For ease of explanation, the setting information for the q-th local sound field is referred to as Info (q) It is written as (q: natural number, 1≦q≦Q).

[0052] Then, the local sound field setting unit 11 generates local sound field setting information Info (q) Based on the local internal sound field A m (q) Then, the local sound field setting unit 11 obtains the local internal sound field A obtained for the Q local sound fields (details will be described later). m (q) The data obtained by compiling the above data is output to the local sound field decomposition processing unit 12 as data D1.

[0053] The local sound field decomposition processing unit 12 receives the data D1 output from the local sound field setting unit 11, performs local sound field decomposition processing using the data D1, and separates the Q local sound fields into a global internal sound field and a global external sound field. The local sound field decomposition processing unit 12 then outputs the data on the global internal sound field and the global external sound field acquired by the local sound field decomposition processing to the optimization processing unit 13 as data D2.

[0054] The optimization processing unit 13 receives the data D2 output from the local sound field decomposition processing unit 12, performs optimization processing using the data D2, and acquires data on the global internal sound field and global external sound field after the optimization processing. The optimization processing unit 13 then outputs the acquired data on the global internal sound field and global external sound field after the optimization processing as data D3 to the global sound field simultaneous reproduction processing unit 14.

[0055] The global sound field simultaneous reproduction processor 14 inputs data D3 output from the optimization processor 13, and executes global sound field simultaneous reproduction processing using the data D3 to obtain a drive signal sig_Dint for driving the internal sound field speaker array Spk_int and a drive signal sig_Dext for driving the external sound field speaker array Spk_ext. The global sound field simultaneous reproduction processor 14 then (1) drives the internal sound field speaker array Spk_int with the drive signal sig_Dint, causing the internal sound field speaker array Spk_int to generate sound based on the drive signal sig_Dint, and (2) drives the external sound field speaker array Spk_ext with the drive signal sig_Dext, causing the internal sound field speaker array Spk_int to generate sound based on the drive signal sig_Dext.

[0056] The speaker array Spk_int for the internal sound field (speaker array Spk_int for the arrival sound field) has a radius r i are arranged at approximately equal intervals on the circumference of a circle with a radius of r i The internal sound field speaker array Spk_int is driven by a drive signal sig_Dint output from the global sound field simultaneous reproduction processor 14.

[0057] As shown in FIGS. 2 and 3, each speaker constituting the internal sound field speaker array Spk_int is represented as Spk_int.i (i: natural number, 1≦i≦N1 (N1=16 in the case of FIGS. 2 and 3)).

[0058] The speaker array Spk_ext for the external sound field (speaker array Spk_ext for the radiation sound field) has a radius r e On the circumference of a circle (radius r i A circle with the same center as the circle of radius r e are arranged at approximately equal intervals on a circle of radius r e The spheres are arranged in a direction that generates sound waves in the radial outward direction (radiation direction) of the circle.

[0059] The speaker array Spk_ext for an external sound field (speaker array Spk_ext for a radiation sound field) is arranged on the boundary line of the cylindrical baffle Baf1 in plan view, as shown in, for example, FIGS.

[0060] The external sound field speaker array Spk_ext is driven by a drive signal sig_Dext output from the global sound field simultaneous reproduction processor 14 .

[0061] As shown in FIGS. 2 and 3, each speaker constituting the external sound field speaker array Spk_ext is represented as Spk_ext.i (i: natural number, 1≦i≦N2 (N2=8 in the case of FIGS. 2 and 3)).

[0062] The function of the “local sound field decomposition optimization processing unit” is realized by the local sound field decomposition processing unit 12 and the optimization processing unit 13 .

[0063] <1.2: Operation of the sound field control system> The operation of the sound field control system 1000 configured as above will be described below.

[0064] FIG. 4 is a flowchart of the processing executed by the sound field control system 1000.

[0065] For the sake of convenience, Q local sound field zones Zone (1) ~Zone (Q) An example where (Q: natural number) is a circular area of ​​radius R1 in plan view will be described with reference to a flowchart.

[0066] (Step S1): In step S1, a local sound field setting process is executed. Specifically, the following process is executed.

[0067] The local sound field setting unit 11 sets information Info such as the position, size, direction of sound waves, whether it is a silent area, etc. for each of the Q local sound fields. (q) (q: natural number, 1≦q≦Q)

[0068] Then, the local sound field setting unit 11 generates local sound field setting information Info (q) Based on the local internal sound field A m (q) This process will be explained below.

[0069] As shown in Figure 3, in plan view, two concentric circles (center O (origin O) and radius r i circle with radius r e The position vector of the region surrounded by the circle (the radius r) and the angle φ with the reference axis Ax_ref is defined as vector r. The position vector r is expressed as the following formula.

number

number

number

number

number

[0070] Then, the local sound field setting unit 11 sets the acquired Q local internal sound fields A m (q) Obtain data a in matrix format from (1≦q≦Q). Data a (matrix a of (2M+1)Q×1) is as follows:

number

[0071] Then, the local sound field setting unit 11 calculates the local internal sound field A obtained for the Q local sound fields. m (q) The data a (matrix a) obtained by summarizing the above data is output to the local sound field decomposition processing unit 12 as data D1.

[0072] (Step S2): In step S2, a local sound field decomposition process is performed. Specifically, the following process is performed.

[0073] In order to perform local sound field decomposition processing, the local sound field decomposition processing unit 12 sets a matrix T for expressing the matrix a output from the local sound field setting unit 11 by the following mathematical formula, and a vector b of the two-dimensional cylindrical harmonic spectrum of the global internal and external mixed sound field (obtaining the matrix expression based on (Mathematical Formula 5)).

number

number

[0074] For this reason, the local sound field decomposition processing unit 12 calculates the matrix a and the matrix T (=[T i T e ]) and the matrix b are output to the optimization processing unit 13 as data D2.

[0075] (Step S3): In step S3, optimization processing is performed. Specifically, the following processing is performed.

[0076] The optimization processing unit 13 receives the data D2 (={a, T, b}, a=Tb) output from the local sound field decomposition processing unit 12. The optimization processing unit 13 then extracts (1) a matrix T obtained by extracting only the coefficient portion corresponding to the local sound field region set in the voiced region (bright zone) from the matrix T. b (2) Matrix T extracted from the coefficients corresponding to the local sound field area set in the silent area (dark zone) d The optimization processing unit 13 also obtains a matrix A b For example, get the area Zone (1) , area Zone (2) , and Zone (5)Only the area with sound is the area with sound. (q) If the region is silent, the matrix obtained by extracting only the first, second, and fifth rows of matrix T is matrix T b The matrix obtained by extracting only the rows other than those mentioned above from matrix T is matrix T d And, A b is the following matrix: A b =[A -M (1) ,···,A M (1) ,A ―M (2) ,A M (2) ,A ―M (5) ,A M (5) ] Then, the optimization processing unit 13 performs optimization processing so as to satisfy the conditions of the following formula, for example.

number

number

number

number

[0077] In addition, the optimized solution b opt of b opt =[Ao -Mi ,···,Ao Mi ,Bo -Me ,···,Bo Me ] T It is written as follows.

[0078] In this way, the optimization processing unit 13 optimizes the local sound fields as follows: (1) Optimized global internal sound field (b opt [Ao -Mi ,···,Ao Mi ] part (two-dimensional cylindrical harmonic spectrum), and (2) Optimized global external sound field (b opt [Bo -Me ,···,Bo Me ] part (2D cylindrical harmonic spectrum) can be decomposed into

[0079] Then, the optimization processing unit 13 calculates the obtained optimization solution b opt The data including the above is output to the global sound field simultaneous reproduction processing unit 14 as data D3.

[0080] (Step S4): In step S3, a global sound field simultaneous reproduction process is executed. Specifically, the following process is executed.

[0081] The global sound field simultaneous reproduction processing unit 14 processes the data D3 (data of two-dimensional cylindrical harmonic spectrum separated into the global internal sound field and the global external sound field) (b opt =[Ao -Mi ,···,Ao Mi ,Bo -Me ,···,Bo Me ] T In general, the separated global interior sound field and the global exterior sound field can be reproduced by analytical higher-order Ambisonics. For example, the driving function D of the global interior sound field is obtained by using the method (analytical higher-order Ambisonics) of the prior art document B below. m (r i ), and the driving function D of the global external sound field m (r e ) can be expressed as the following formula: (Prior art document B): J. Ahrens and S. Spors, "An analytical approach to sound field reproduction using circular and spherical loudspeaker distributions," Acta Acust. Acust., vol. 94, no. 6, pp. 988-999, Nov. 2008.

number

number

[0082] In the sound field control system 1000, as shown in FIGS. 2 and 3, in a plan view, an origin O is set as the center and a radius r e Since the cylindrical baffle Baf1 is provided, the driving function D of the global external sound field can be calculated by the method disclosed in the following prior art documents C and D. m (r e ) is expressed as the following formula: (Prior art document C): T. Okamoto, "Mode-matching-based sound field recording and synthesis with circular double-layer arrays," Appl. Sci., vol. 8, no. 7, 1048, July, 2018. (Prior art document D): MA Poletti and TD Abhayapala, "Interior and exterior sound field control using general two-dimensional first-order sources," J. Acoust. Soc. Am., vol. 129, no. 1, pp. 234-244, Jan. 2011.

number

[0083] The global sound field simultaneous reproduction processor 14 uses the data D3 (data of two-dimensional cylindrical harmonic spectrum separated into the global internal sound field and the global external sound field) output from the optimization processor 13 to calculate (b opt =[Ao -Mi ,···,Ao Mi ,Bo -Me ,···,Bo Me ] T (using the two-dimensional cylindrical harmonic spectrum of the m (r i ) (spatial frequency domain driving function D m (r i )), and (2) the driving function D of the global external sound field m (r e ) (spatial frequency domain driving function D m (r e)) to get the

[0084] The global sound field simultaneous reproduction processor 14 performs processing corresponding to the following formula to obtain (1) the driving function D(r i ,φ L ), and (2) the driving function D(r e ,φ L ) to get the

number

[0085] The global sound field simultaneous reproduction processor 14 (1) generates a driving signal sig_Dint (a driving function D(r i ,φ L )) to drive the internal sound field speaker array Spk_int with the drive signal sig_Dint, and (2) to drive the external sound field speaker array Spk_ext with the drive signal sig_Dext (corresponding to the driving function D(r e ,φ L ) and drives the internal sound field speaker array Spk_int with the drive signal sig_Dint.

[0086] This allows appropriate sound field control for multiple local sound fields (Zone (1) ~Zone (Q) (Multi-sound field control can be performed to make the local sound field closer to the set sound field.)

[0087] As described above, the sound field control system 1000 decomposes and optimizes multiple local sound fields into (1) one global internal sound field and (2) one global external sound field, and then simultaneously reproduces the decomposed and optimized global internal sound field and global external sound field using the internal / external mode control method (simultaneously reproduces using the internal sound field speaker array Spk_int and the external sound field speaker array Spk_ext). Therefore, the sound field control system 1000 can solve the occlusion problem (without causing the occlusion problem) and perform appropriate sound field control on multiple local sound fields regardless of the sound wave propagation direction.

[0088] Here, experimental results of the present invention are presented.

[0089] Figure 5 shows the local sound field area, Zone (1) , and Zone (2) Set the local sound field area Zone (1) is set as a silent area, and the local sound field area Zone (2) is set as the sound area, and (a) the global internal sound field, (b) the global external sound field, and (c) the global internal / external mixed sound field are shown when the present invention is applied. In the case of Fig. 5, sound waves with a frequency f = 500 Hz traveling in the direction of φ = π, i.e., 180°, are generated from an internal sound source (a sound source at the center of the area ROI_global) and an external sound source (a sound source outside the area ROI_global).

[0090] As can be seen from FIG. 5, by applying the present invention, it is possible to separate the sound field into an appropriate (a) global internal sound field and a (b) global external sound field. Furthermore, in the (c) global internal / external mixed sound field, which is a synthesis (mixing) of the (a) global internal sound field and the (b) global external sound field, the local sound field area Zone (1) In this case, it is a silent area and the local sound field area Zone (2) In other words, by applying the present invention, it is possible to obtain a sound field by dividing each of the local sound fields (local sound field areas (1) , Zone(2) It can be seen that the global internal sound field and the global external sound field can be correctly represented by the sum of the global internal sound field and the global external sound field.

[0091] FIG. 6 is a diagram showing the results of a comparison between a global internal synthesized sound field according to the prior art and a global internal / external mixed (synthesized) sound field according to the present invention.

[0092] The top part of Figure 6 shows the results of a global internal synthesized sound field using conventional technology, and shows (A1) the global internal synthesized sound field, (A2) the sound field synthesis error, and (A3) the sound pressure level when only the internal sound field speaker array Spk_int is installed and the number of speakers that make up the internal sound field speaker array Spk_int is Li = 64 (when there is no external sound field speaker array Spk_ext (Le = 0)).

[0093] The bottom part of Figure 6 shows the results of a global internal / external mixed (synthesized) sound field according to the present invention, showing (B1) the global internal / external mixed (synthesized) sound field, (B2) the sound field synthesis error, and (B3) the sound pressure level when an internal sound field speaker array Spk_int (number of speakers Li = 53) and an external sound field speaker array Spk_ext (number of speakers Le = 11) are installed.

[0094] In FIG. 6, the direction of propagation of the sound wave is φ=π / 4, and the local sound field area Zone (1) is set as a silent area, and the local sound field area Zone (2) is set to the voiced region.

[0095] From Figure 6, it can be seen that even in this case (when the sound wave propagation direction is φ=π / 4), the global internal and external mixed (synthesized) sound field according to the present invention is superior to the global internal synthesized sound field according to the prior art in terms of sound pressure synthesis error and sound pressure level.

[0096] FIG. 7 is a diagram showing the results of a comparison between a global internal synthesized sound field according to the prior art and a global internal / external mixed (synthesized) sound field according to the present invention.

[0097] The top part of Figure 7 shows the results of a global internal synthesized sound field using conventional technology, and shows (A1) the global internal synthesized sound field, (A2) sound field synthesis error, and (A3) sound pressure level when only the internal sound field speaker array Spk_int is installed and the number of speakers that make up the internal sound field speaker array Spk_int is Li = 64 (when there is no external sound field speaker array Spk_ext (Le = 0)).

[0098] The bottom part of Figure 7 shows the results of a global internal / external mixed (synthesized) sound field according to the present invention, showing (B1) the global internal / external mixed (synthesized) sound field, (B2) the sound field synthesis error, and (B3) the sound pressure level when an internal sound field speaker array Spk_int (number of speakers Li = 53) and an external sound field speaker array Spk_ext (number of speakers Le = 11) are installed.

[0099] In FIG. 7, the direction of propagation of the sound wave is φ=π, and the local sound field area Zone (1) is set as a silent area, and the local sound field area Zone (2) is set to the voiced region.

[0100] From Figure 7, it can be seen that even in this case (when the sound wave propagation direction is φ = π), the global internal and external mixed (synthesized) sound field according to the present invention is far superior in terms of sound pressure synthesis error and sound pressure level to the global internal synthesized sound field according to the prior art.

[0101] In particular, in the global internal synthesized sound field of the prior art, the propagation direction of the sound wave and the position vector of the local sound field area (position vector based on the origin O) are parallel, so it is not possible to obtain the optimal combination (optimal solution) of the two-dimensional cylindrical harmonic spectrum. As a result, it is not possible to properly combine the local sound field area Zone (1) cannot be a silent area and the local sound field area Zone (2) cannot be a voiced region (occlusion problem occurs).

[0102] On the other hand, in the global internal and external mixed (synthesized) sound field according to the present invention, even if the propagation direction of the sound wave and the position vector of the local sound field area (position vector based on the origin O) are parallel, it is possible to obtain the optimal combination (optimal solution) of the two-dimensional cylindrical harmonic spectrum. As a result, the local sound field area Zone (1) can be a silent area and appropriately, the local sound field area Zone (2) can be made into a voiced region (the occlusion problem is solved).

[0103] In the present invention (sound field control system 1000), by introducing an external sound field, it is possible to appropriately decompose and optimize multiple local sound fields into (1) one global internal sound field and (2) one global external sound field, regardless of the traveling direction of sound waves. Then, in the present invention (sound field control system 1000), the decomposed and optimized global internal sound field and global external sound field are simultaneously reproduced using an internal / external mode control method (simultaneous reproduction using a speaker array Spk_int for the internal sound field and a speaker array Spk_ext for the external sound field). Therefore, in the present invention (sound field control system 1000), the occlusion problem is solved (without occurring), and appropriate sound field control can be performed on multiple local sound fields regardless of the traveling direction of sound waves.

[0104] Figure 8 also shows (1) a diagram (left) showing the relationship between the propagation direction of a plane wave and the synthesis error of the synthesized sound field according to the present invention and the conventional technology, and (2) a diagram (right) showing the relationship between the propagation direction of a plane wave and the acoustic contrast of the synthesized sound field according to the present invention and the conventional technology.

[0105] It can also be seen from FIG. 8 that the global internal and external mixed (synthesized) sound field according to the present invention is far superior to the global internal synthesized sound field according to the prior art.

[0106] <First Modification> Next, a first modified example of the first embodiment will be described. Note that the same parts as those in the above-described embodiment will be given the same reference numerals, and detailed description thereof will be omitted.

[0107] In this modification, an example in which a multilingual speech translation system 1000MT is realized using the sound field control system 1000 will be described.

[0108] FIG. 9 is a schematic diagram of a multilingual speech translation system 1000MT according to a first modified example of the first embodiment.

[0109] FIG. 10 is a diagram (viewed from above) that schematically shows the recording state of the original sound field in a multilingual speech translation system 1000MT according to a first modified example of the first embodiment.

[0110] FIG. 11 is a diagram (showing a local sound field region) for explaining multilingual multi-sound field reproduction in the multilingual speech translation system 1000MT of the first modified example of the first embodiment.

[0111] As shown in FIG. 9, the multilingual speech translation system 1000MT includes a microphone array μphone_array for recording the original sound field, a speech recognition machine translation speech synthesis device Dev_MT, and a sound field control system 1000 (sound field control system 1000 including a sound field control device 100, a speaker array Spk_int for an internal sound field, a speaker array Spk_ext for an external sound field, etc., as in the first embodiment).

[0112] For example, a case will be described in which a speaker, Person.JP, speaks in Japanese in a predetermined space and the Japanese voice is recorded by the microphone array μphone_array, as shown in Fig. 10. The area in which the microphone array μphone_array is arranged has approximately the same shape and size (approximately the same area) as the local sound field area of ​​the sound field control system 1000.

[0113] The microphone array μphone_array records the Japanese speech of the speaker Person.JP and outputs the recorded speech signal (sound field signal) as a speech signal (sound field signal) Sig_org to the speech recognition / machine translation / speech synthesis device Dev_MT and the sound field control device 100.

[0114] The speech recognition machine translation speech synthesis device Dev_MT receives a speech signal (sound field signal) Sig_org (Japanese speech signal) as input, performs speech recognition processing on the speech signal (sound field signal) Sig_org (Japanese speech signal), and acquires Japanese text data. The speech recognition machine translation speech synthesis device Dev_MT then performs machine translation processing on the acquired Japanese text data (original language data) and acquires one or more machine-translated language data. The speech recognition machine translation speech synthesis device Dev_MT then performs speech synthesis processing on the acquired one or more machine-translated language data and acquires a speech signal sig_MT of the one or more machine-translated language data. The speech recognition machine translation speech synthesis device Dev_MT then outputs the acquired speech signal sig_MT to the sound field control device 100. For ease of explanation, the following description will be given assuming that the speech recognition machine translation speech synthesis device Dev_MT machine-translates the original language data (Japanese data) and acquires Chinese data and English data.

[0115] The sound field control device 100 inputs the original language (Japanese) audio signal (sound field signal) sig_org output from the microphone array μphone_array and the audio signal sig_MT output from the speech recognition machine translation speech synthesis device Dev_MT (the audio signal of data machine-translated into Chinese and the audio signal of data machine-translated into English).

[0116] The local sound field setting unit 11 of the sound field control device 100 (1) Local sound field zone (1) is set to a local sound field that reproduces the original (Japanese) audio signal (sound field signal) sig_org, (2) Local sound field zone (2)is set to a local sound field that reproduces the speech signal (sound field signal) sig_MT (machine-translated Chinese speech data) that has been machine-translated from the original language (Japanese) to Chinese. (3) Local sound field zone (3) is set to a local sound field that reproduces the audio signal (sound field signal) sig_MT (machine-translated English audio data) that has been machine-translated from the original language (Japanese) to English.

[0117] The local sound field can be set by the method described in the first embodiment.

[0118] Then, the sound field control device 100 executes the same processing as in the first embodiment to reproduce the above-mentioned local sound field, and acquires (1) a drive signal sig_Dint for driving the speaker array Spk_int for the internal sound field, and (2) a drive signal sig_Dext for driving the speaker array Spk_ext for the external sound field.

[0119] Then, by driving the speaker array Spk_int for the internal sound field and the speaker array Spk_ext for the external sound field using the obtained drive signal sig_Dint and the drive signal sig_Dext for driving the speaker array Spk_ext for the external sound field, as shown in Figs. 9 and 11, (1) Local sound field zone (1) The original (Japanese) audio signal (sound field signal) sig_org is reproduced. (2) Local sound field zone (2) The original language (Japanese) is machine-translated into Chinese, and the machine-translated Chinese audio signal (sound field signal) sig_MT (machine-translated Chinese audio data) is played back. (3) Local sound field zone (3) The original language (Japanese) is machine-translated into English and the machine-translated audio signal (sound field signal) sig_MT (machine-translated English audio data) is played. It is possible.

[0120] In this way, the multilingual speech translation system 1000MT of this modified example can use the sound field control system 1000 to realize a multilingual speech translation process that simultaneously reproduces (plays back) speech in different languages ​​in multiple local sound fields.

[0121] Furthermore, the speaker Person.JP may be photographed in the space where the original sound field is recorded, and a hologram image holo1 (or a three-dimensional image) of the speaker Person.JP may be reproduced (played back) in the central portion (for example, the area near the baffle Baf) as shown in Figure 11.

[0122] In the above, we have described a case where Japanese is machine-translated into Chinese and English, and (1) Japanese (original language), (2) machine-translated Chinese, and (3) machine-translated English are played back (reproduced) in three local sound fields, but this is not limiting, and the original language may be other than Japanese, and the machine-translated languages ​​may also be other languages. Furthermore, the number of languages ​​to be machine-translated may also be a number other than "2."

[0123] [Second embodiment] Next, a second embodiment will be described.

[0124] In the second embodiment, a system (sound field control system) that performs sound field control by the weighted mode control method disclosed in Non-Patent Document A below, which takes mutual diffusion into consideration, will be described. (Non-patent document A): N. Ueno, S. Koyama, and H. Saruwatari, "Listening-area-informed sound field reproduction based on circular harmonic expansion," in Proc. ICASSP, Mar. 2017, pp. 111-115. When using circular or spherical baffles for sound field control, it is necessary to take into account the diffusion caused by the baffles, and when there is only one speaker array, sound field control is performed taking into account a diffusion called "self-diffusion." Furthermore, when there are multiple speaker arrays and the baffles are close to each other, not only self-diffusion occurs but also mutual diffusion between the baffles.

[0125] For example, the method of Non-Patent Document B below only takes self-diffusion into consideration, and therefore has the problem that when speaker arrays are placed closely together, the control performance in sound field control deteriorates. (Non-patent document B): MA Poletti, TD Abhayapala, and P. Samarasinghe, "Interior and exterior sound field control using two dimensional higher-order variable-directivity sources," J. Acoust. Soc. Am., vol. 131, no. 5, pp. 3814-3823, May 2012. In order to solve the above problem, the sound field control system of this embodiment performs sound field control using a weighted mode control method that takes mutual diffusion into consideration.

[0126] in particular, (1) The formulation of mutual diffusion, which is taken into account in multiple circular microphone arrays (see, for example, the technology in Non-Patent Document C below), is improved, and the transfer function between each speaker and the control target area is derived while taking mutual diffusion into account. (2) In addition, in order to calculate the entire reproduced sound field, the transfer function between each speaker and the reproduction point is also derived.

[0127] These results enable the realization of multi-sound field control using multiple circular arrays taking into account mutual diffusion using the weighted mode control method. (Non-patent document C): M. Nakanishi, N. Ueno, S. Koyama, and H. Saruwatari, "Two-dimensional sound field recording with multiple circular microphone arrays considering multiple scattering," in Proc. WASPAA, Oct. 2019, pp. 368-372. <2.1: Sound field control system configuration> FIG. 12 is a schematic diagram of a sound field control system 2000 according to the second embodiment.

[0128] FIG. 13 is a schematic configuration diagram (plan view seen from above) of a speaker array (one example) of a sound field control system 2000 according to the second embodiment.

[0129] FIG. 14 is a diagram schematically showing a baffle and a speaker array (one example) of a sound field control system 2000 according to the second embodiment.

[0130] As shown in FIG. 12, the sound field control system 2000 includes a sound field control device 200 and a speaker group Spk_grp.

[0131] The sound field control device 200 includes a sound field setting processor 21, a transfer function matrix setting processor 22, a multiple diffuse component data acquisition processor 23, a speaker-to-control area transfer function acquisition processor 24, and a sound field reproduction processor 25.

[0132] The sound field setting processor 21 sets information about one or more sound fields. For ease of explanation, in the sound field control system 2000, the target areas for sound field control (referred to as "control target areas") are divided into Q areas (Q: natural number, Q≧2) (Q control target areas V1 to V2 in FIG. 13). Q A case where a sound field set as follows (in FIG. 13, Q=3 and each control target area is a circular area in a plan view) is set will be described below.

[0133] The sound field setting processor 21 sets information such as the position, size, direction of sound waves, whether or not it is a silent area, etc. for each of the Q control target areas. For ease of explanation, the setting information for the qth control target area is referred to as Info (q) It is written as (q: natural number, 1≦q≦Q).

[0134] Then, the sound field setting processing unit 21 calculates the set information Info for each of the Q control target areas. (q) The data including the above is output as data D21 to the transfer function matrix setting processing unit 22, the multiple diffuse component data acquisition processing unit 23, the speaker-to-control area transfer function acquisition processing unit 24, and the sound field reproduction processing unit 25.

[0135] The transfer function matrix setting processing unit 22 receives the data D21 output from the sound field setting processing unit 21 and performs processing to set a transfer function matrix based on the data D21 (details will be described later). Then, the transfer function matrix setting processing unit 22 outputs data including the above processing results as data D22 to the multiple diffuse component data acquisition processing unit 23.

[0136] The multiple diffuse component data acquisition processing unit 23 receives the data D21 output from the sound field setting processing unit 21 and the data D22 output from the transfer function matrix setting processing unit 22, and performs processing to acquire multiple diffuse component data based on the data D21 and D22 (details will be described later).The multiple diffuse component data acquisition processing unit 23 then outputs data including the results of the above processing as data D23 to the speaker-to-control target area transfer function acquisition processing unit 24.

[0137] The speaker-to-control target area transfer function acquisition processing unit 24 receives the data D21 output from the sound field setting processing unit 21 and the data D23 output from the multiplexed diffusion component data acquisition processing unit 23, and performs processing to acquire a speaker-to-control target area transfer function that takes multiplexed diffusion into consideration based on the data D21 and D23 (details will be described later).The speaker-to-control target area transfer function acquisition processing unit 24 then outputs data including the above processing results as data D24 to the sound field reproduction processing unit 25.

[0138] The sound field reproduction processing unit 25 receives data D21 output from the sound field setting processing unit 21 and data D24 output from the speaker-to-control target area transfer function acquisition processing unit 24. The sound field reproduction processing unit 25 performs sound field reproduction processing based on the data D21 and D24, and acquires drive signals sig_Drv for driving each speaker. The sound field reproduction processing unit 25 then outputs the acquired drive signals sig_Drv to each speaker (speaker group Spk_grp).

[0139] The speaker group Spk_grp is a plurality of speakers for reproducing a desired sound field in the control target area, and each speaker included in the speaker group Spk_grp is driven by a drive signal output from the sound field reproduction processing unit 25. For example, in the case shown in Fig. 13, in which seven baffles Baf1 to Baf7 and three control target areas V1 to V3 are arranged, each baffle is a cylindrical baffle, and eight speakers are evenly arranged on the surface of the baffle around a circle in a plan view, all of the speakers installed on the seven baffles Baf1 to Baf7 are the speaker group Spk_grp.

[0140] For convenience, the speakers installed on the baffle Bafk (k: natural number) are denoted as Bk.spi (i: natural number) as shown in Fig. 14. In the case of Fig. 14, eight speakers are installed on the baffle Bafk (k: natural number), and these eight speakers are denoted as Bk.sp1 to Bk.sp8 as shown in Fig. 14.

[0141] <2.2: Operation of the sound field control system> The operation of the sound field control system 2000 configured as above will be described below.

[0142] FIG. 15 is a diagram (plan view seen from above) that schematically shows the arrangement of the baffle, the speaker, and the area to be controlled.

[0143] FIG. 16 is a flowchart of the process executed by the sound field control system 1000 (sound field control process taking multiple diffusion into consideration).

[0144] For the sake of convenience, the sound field control system 2000 will be described below as having I (I: natural number) cylindrical baffles Baf1 to Baf I , Q (Q: natural number) control target areas V1 to V Q , and L speakers SP1 to SP L For example, the coordinate system shown in Fig. 15 (a two-dimensional coordinate system with a predetermined position as the origin) is used to identify the position information of the baffle, the area to be controlled, and the speaker.

[0145] In the sound field control system 2000, (1) Cylindrical baffle Baf i is the radius R in plan view i (i: natural number, 1≦i≦I) baffles, (2) Control area V q is the radius R in plan view q (q: natural number, 1≦q≦Q) (3) Speaker Sp l is the position vector r l A speaker installed at a position specified by (l: natural number, 1≦l≦L) The following description will be given assuming that:

[0146] (Step S21): In step S21, a sound field setting process for the control target area is executed. Specifically, the following process is executed.

[0147] The sound field setting processor 21 sets information about one or more sound fields (areas to be controlled). That is, the sound field setting processor 21 sets information about Q control areas V1 to V Q For each of these, information such as the position, size, direction of the sound wave, whether it is a silent area, etc. (q) (q: natural number, 1≦q≦Q) is set. Then, the sound field setting processing unit 21 sets the set information Info (q) is included in data D21.

[0148] The sound pressure at the position specified by the position vector r can be expressed by a two-dimensional cylindrical harmonic series expansion. Therefore, the sound pressure P at the position specified by the position vector r when the desired sound field is realized is des (r) is approximated by the following formula (N q can be expressed as (approximation up to the next level).

number

number

[0149] The sound field setting processing unit 21 controls the control target area V q Depending on the sound field you want to achieve, you can select the control area V q Two-dimensional cylindrical harmonic spectrum of the nth order sound field a n (q) For example, as shown in Fig. 13, when (1) the control target area V1 is set to a silent area, (2) the control target area V2 is set to a sound area (a sound field area reproducing a first sound), and (3) the control target area V3 is set to a sound area (a sound field area reproducing a second sound), the sound field setting processing unit 21 (1) calculates a two-dimensional cylindrical harmonic spectrum a of the n-th order sound field for the control target area V1. n (1) is set to a value that realizes a silent region, and (2) the two-dimensional cylindrical harmonic spectrum a of the nth-order sound field for the control target area V2 n (2) is set to a value that realizes the voiced area (the sound field area that reproduces the first sound), and (3) the two-dimensional cylindrical harmonic spectrum a of the n-th order sound field for the control target area V3 n (3) is set to a value that realizes a voiced region (a sound field region that reproduces the second sound).

[0150] Then, the sound field setting processing unit 21 sets the control target area V q Two-dimensional cylindrical harmonic spectrum of the nth order sound field a n (q) are also included in the data D21, and the data D21 is output to the transfer function matrix setting processing unit 22.

[0151] (Step S22): In step S22, a process of setting a matrix of transfer functions (transfer function matrix) between baffles taking mutual diffusion into consideration is executed.

[0152] Here, the underlying technology will be explained first.

[0153] Position vector r l The speaker (lth speaker) installed at the position specified by and I baffles Baf1 to Baf I The sound field (total sound field) generated by the diffuse components of total (l) (r) (the sound field at the position specified by the position vector r) can be expressed by the following formula.

number

number

number

[0154] Also, the center point is O i The two-dimensional cylindrical harmonic spectrum of the total incident sound field on the i-th baffle is

number

number

[0155] and the two-dimensional cylindrical harmonic spectrum γ of the total incident sound field on the i-th baffle (i,l) can be expressed by the following formula:

number

number

[0156] Also, the matrix T in (Equation 24) (i,l) is the matrix of the transfer function between the loudspeaker and the baffle, taking into account the diffusion caused by the loudspeaker, as follows:

number

[0157] As mentioned above, (1) the matrix T of the transfer function between the baffles considering mutual diffusion (i,i’) , and (2) the matrix T of the transfer function between the speaker and the baffle, taking into account the diffusion caused by the speaker. (i,l) can be derived.

[0158] In step S22, the transfer function matrix setting processing unit 22 acquires information about each baffle from the data D21, and based on the acquired information, calculates the transfer function matrix of the above (Equation 25), that is, the matrix T of the transfer function between the baffles taking mutual diffusion into consideration. (i,i’) Set.

[0159] (Step S23): In step S23, a process for setting a matrix of transfer functions (transfer function matrix) between the speaker and the baffle, taking into account the diffusion by the speaker, is executed. Specifically, the following process is executed.

[0160] The transfer function matrix setting processing unit 22 acquires information on each baffle and information on each speaker from the data D21, and based on the acquired information, calculates the transfer function matrix of the above (Equation 26), that is, the matrix T of the transfer function between the speaker and the baffle taking into account the diffusion by the speaker. (i,l) Set.

[0161] Then, the transfer function matrix setting processing unit 22 calculates the matrix T of the transfer function between the baffles taking into account the mutual diffusion obtained in step S22. (i,i’) , and a matrix T of the transfer function between the speaker and the baffle taking into account the diffusion by the speaker obtained in step S23. (i,l) The data D23 including the above is output to the multiple diffused component data acquisition processing unit 23.

[0162] (Step S24): In step S24, a process of setting a matrix taking multiple diffusion into consideration is executed. Specifically, the following process is executed.

[0163] The two-dimensional cylindrical harmonic spectrum γ of the total incident sound field on the i-th baffle, derived by (Eq. 24), (i,l) By substituting into (Equation 23), the following equation is obtained.

number

number

number

number

number

number

[0164] Then, the multiplexed diffuse component data acquisition processing unit 23 outputs data including the data of the matrix set above to the speaker-to-control target area transfer function acquisition processing unit 24 as data D23.

[0165] (Step S25): In step S25, a process for acquiring multiple diffuse component data using a pseudo-inverse matrix is ​​executed. Specifically, the following process is executed.

[0166] The multiple diffusion component data acquisition processing unit 23 obtains the matrix b (l) To obtain this, the process corresponding to the following formula is performed.

number

[0167] The multiple diffusion component data acquisition processing unit 23 uses the matrix b (l) The data including the data (multiple diffuse component data) is output to the speaker-to-control target area transfer function acquisition processing unit 24 as data D23.

[0168] (Step S26): In step S26, a process is executed to acquire a transfer function between the speaker and the control target area based on the multiple diffuse components acquired in step S25. Specifically, the following process is executed.

number

[0169] The synthesized sound field (synthesized sound pressure) produced by L speakers at a position specified by a position vector r can be expressed by the following formula.

number

number

[0170] According to (Equation 34), β (l) and c (q,l) The transfer function between the diffuse sound field component data for the l-th speaker and the coefficient data for determining the transfer function (drive function) between the l-th speaker and the q-th control target area is obtained. Note that this transfer function is obtained by the formula (T (q,l) +[T (q,1) ···T (q,I) ]A + MT (l) )

[0171] In step S26, the speaker-to-control area transfer function acquisition processing unit 24 calculates the transfer function T (q,l) +[T (q,1) ···T (q,I) ]A + MT (l) ) to obtain the transfer function between the speaker and the control target area based on the multiple diffuse components.

[0172] Then, the speaker-to-control area transfer function acquisition processing unit 24 outputs data including the transfer function acquired as described above to the sound field reproduction processing unit 25 as data D24.

[0173] (Step S27): In step S27, the process of acquiring the drive signals for each speaker by the weighted mode control method is executed. Specifically, the following process is executed.

[0174] The sound field reproduction processing unit 25 receives the data D21 output from the sound field setting processing unit 21 and the data D24 output from the speaker-to-control area transfer function acquisition processing unit 24, and performs processing corresponding to the following formula based on the data D21 and data D24 to acquire drive signals (matrix do of drive signals) for driving each speaker.

number

[0175] The synthesized sound field (synthesized sound pressure) by L speakers at a position specified by a position vector r can be expressed by (Equation 35). The sound field (desired sound field) to be realized at the position vector r can be expressed by p des (r), then the sound field p des (r) can be expressed by the following formula.

number

[0176] Then, the synthesized sound field of the Q control target areas is expressed as the desired sound field p des If (r) is desired, an optimization process corresponding to the following formula, that is, a process for finding d (a vector of drive functions for L speakers) that minimizes the objective function J, can be performed.

number

number

[0177] Also, W (q) is a weighted diagonal matrix, whose diagonal elements are weighting coefficients. (q) The diagonal components (weighting coefficients) of w n,n’ (q) can be expressed as follows:

number

[0178] Therefore, in step S27, the sound field reproduction processing unit 25 performs processing equivalent to the above (Equation 39) to obtain the desired sound field p des The drive signals (the matrix do of drive signals) for driving each speaker that reproduces (r) are obtained.

[0179] (Step S28): In step S28, the sound field reproduction process is executed. Specifically, the following process is executed.

[0180] The sound field reproduction processing unit 25 reproduces the desired sound field p obtained in step S27. des Each speaker is driven by a drive signal (a matrix of drive signals do) to reproduce (r), thereby reproducing the desired sound field.

[0181] For example, as shown in FIG. 13, (1) the control target area V1 is set to a silent area, (2) the control target area V2 is set to a sound area (sound field area that reproduces the first sound), and (3) the control target area V3 is set to a sound area (sound field area that reproduces the second sound), and by performing the above processing in the sound field control device 200, (1) a silent area can be realized in the control target area V1, (2) a sound area (sound field area that reproduces the first sound) can be realized in the control target area V2, and (3) a sound area (sound field area that reproduces the second sound) can be realized in the control target area V3.

[0182] <Summary> As described above, the sound field control system 2000 can perform sound field control using the weighted mode control method that takes mutual diffusion into consideration. (1) Set the matrix of the transfer function between the baffles (transfer function matrix) taking into account mutual diffusion, (2) Set the matrix of the transfer function between the speaker and the baffle (transfer function matrix), taking into account the diffusion by the speaker. (3) Using the matrices set in (1) and (2) above, a process of setting a matrix taking multiple diffusion into consideration is performed, and a process of acquiring multiple diffusion component data using a pseudo-inverse matrix is ​​performed.

[0183] In the sound field control system 2000, the sound field control device 200 (4) performing a process of obtaining a transfer function between the speaker and the control target area based on the obtained multiple diffuse components; (5) Based on the transfer function obtained in (4), a process for obtaining a drive signal for each speaker is performed using the weighted mode control method.

[0184] In the sound field control system 2000, the sound field control device 200 drives each speaker using the drive signal acquired as described above, thereby realizing (reproducing) a desired sound field.

[0185] As described above, the sound field control system 2000 performs sound field control using the weighted mode control method that takes mutual diffusion into consideration, and therefore can accurately realize (reproduce) a desired sound field in any region (control target area).

[0186] Furthermore, the sound field control system 2000 can solve the occlusion problem (without causing the occlusion problem) and can appropriately control the sound field for one or more local sound fields (sound fields in the area to be controlled) regardless of the direction of sound wave propagation.

[0187] <Experimental Results> An experiment (computer simulation) was carried out to demonstrate the effectiveness of the present invention, which will be described below.

[0188] (Experiment 1: One controlled area) Experiment 1 was conducted under the following conditions: Fig. 17 is a diagram showing a schematic diagram of the experimental environment.

[0189] (Experimental conditions): Uses a two-dimensional field. ·Sound speed c=343.36[m / s] · The target frequency f ranges from 100Hz to 4kHz. ·Wave number k=2πf / c Eight cylindrical speaker arrays (eight baffles) are used. The radius of each cylindrical speaker array (each baffle) is 0.3m (R i=1,···,8 =0.3 [m]) (see Figure 17). Each baffle has eight omnidirectional speakers evenly spaced around the circumference of its surface (see Figure 17). Therefore, the number of speakers is L = 64. ·Maximum order N of the 2D cylindrical harmonic spectrum of multiple diffuse components i =ceil(ekR i / 2) (ceil(): ceiling function) ·Maximum order N of the 2D cylindrical harmonic spectrum of the synthesized sound field l =ceil(ekR q / 2)+N i λ in (Equation 37) is the value of the following equation

number

[0190] FIG. 19 shows the experimental results of Experiment 1 (when there is one control target area) (a diagram showing the synthesized sound field (synthetic sound pressure) and synthesis error reproduced in the experimental environment). Specifically, the left column shows the synthesized sound field (synthetic sound pressure), and the right column shows the synthesis error. FIG. 19(a) shows the experimental results for the open array. FIG. 19(b) shows the experimental results when only self-dispersion is considered. FIG. 19(c) shows the experimental results when mutual diffusion is considered (corresponding to the present invention (processing in sound field control system 2000)).

[0191] As can be seen from FIG. 19, the experimental results of the present invention are significantly better than when only self-dispersion is considered, and the synthetic sound field reproduced by the present invention is as accurate as that of the open array.

[0192] The experimental results (frequency-synthesis error characteristics) are shown in Figure 20. As can be seen from Figure 20, the experimental results of the present invention are significantly better than when only self-dispersion is considered, and the synthesis error of the synthesized sound field reproduced by the present invention is as small as that of the open array.

[0193] As described above, the sound field reproduced by the present invention is extremely accurate.

[0194] (Experiment 2: Two control areas) Experiment 2 was conducted under the following conditions: Figures 21 and 22 are diagrams that schematically show the experimental environment.

[0195] (Experimental conditions): Uses a two-dimensional field. ·Sound speed c=343.36[m / s] · The target frequency f ranges from 100Hz to 4kHz. ·Wave number k=2πf / c Eight cylindrical speaker arrays (eight baffles) are used. The radius of each cylindrical speaker array (each baffle) is 0.3m (R i=1,···,8=0.3 [m]) (see Figures 21 and 22). Each baffle has eight omnidirectional speakers evenly spaced around the circumference of its surface (see Figures 21 and 22). Therefore, the number of speakers is L = 64. ·Maximum order N of the 2D cylindrical harmonic spectrum of multiple diffuse components i =ceil(ekR i / 2) (ceil(): ceiling function) ·Maximum order N of the 2D cylindrical harmonic spectrum of the synthesized sound field l =ceil(ekR q / 2)+N i λ in (Equation 37) is the value of (Equation 42) Number of controlled areas Q=2 First control area (V1): R q=1 =0.5m, O q=1 =(1,0), radius 2.0m (see Figure 21 and Figure 22) First controlled area (V2): R q=2 =0.5m, O q=2 =(1,π), radius 2.0m (see Figure 21 and Figure 22) Desired sound field (sound field in the first control area V1): q=1, sound field of a single plane wave (traveling direction φ=π) Desired sound field (sound field of the second control target area V2): q=2, silent area Figure 23 shows the experimental results of Experiment 2 (when there were two control target areas) (diagrams showing the synthetic sound field (synthetic sound pressure), synthesis error, and acoustic contrast reproduced in the experimental environment). Specifically, Figure 23(a) shows the experimental results for the arrangement of Figure 21, with the top row showing the synthetic sound pressure, the middle row showing the synthesis error, and the bottom row showing the acoustic contrast. Figure 23(b) shows the experimental results for the arrangement of Figure 22, with the top row showing the synthetic sound pressure, the middle row showing the synthesis error, and the bottom row showing the acoustic contrast.

[0196] As can be seen from Figure 23, in both the arrangement of Figure 21 and the arrangement of Figure 22, the control target area V1 can be reproduced with high accuracy as a silent area, while the control target area V2 can be reproduced as a sound area (an area that reproduces a sound field due to a plane wave in the propagation direction π).

[0197] As described above, the sound field reproduced by the present invention is extremely accurate, and furthermore, even in situations where occlusion problems occur with conventional methods as described above, the present invention can reproduce a highly accurate sound field (desired sound field) without causing occlusion problems.

[0198] <<Variations>> Note that the second embodiment can also be applied to a multilingual speech translation system, as in the first modification of the first embodiment. In this case, the system is configured so that speech signals in a plurality of different languages ​​are reproduced for a plurality of sound field control target regions, as in the first modification of the first embodiment.

[0199] [Other embodiments] In the above embodiment (including the modified examples), the case where processing is performed using a two-dimensional cylindrical harmonic spectrum in the sound field control system 1000 has been described. However, this is not limited to this, and processing may also be performed using a three-dimensional spherical harmonic spectrum (separating and optimizing multiple local sound fields into a global internal sound field and a global external sound field, and then simultaneously reproducing the separated and optimized global internal sound field and global external sound field using an internal / external mode control method). In this case, the internal sound field speaker array Spk_int and the external sound field speaker array Spk_ext are arranged spherically. Furthermore, it is preferable to provide a spherical baffle within the spherical surface on which the external sound field speaker array Spk_ext is arranged to prevent sound waves from propagating.

[0200] Furthermore, in the above embodiment (including the modified examples), a case has been described in which processing is performed by a mode control method in the sound field control system 1000, but this is not limited to this, and processing may also be performed by a sound pressure control method.

[0201] Furthermore, in the above embodiment (including modified examples), the speaker array is described as being arranged in a circle when viewed in a plane, but this is not limited to this, and the speaker array may be arranged in other forms (styles) as long as it is arranged (arranged) to surround a specified area, such as when it is arranged in a rectangular shape when viewed in a plane.

[0202] Furthermore, in the above embodiment (including the modified examples), the case where the objective function (loss function) L(b) in the sound field control system 1000 is (Equation 10) has been described, but the present invention is not limited to this. For example, optimization processing may be performed using an objective function (loss function) that takes into account (evaluates) one or more of the following: (1) acoustic contrast, (2) bright zone error (error in the sound-active region), (3) speaker array effect (effect based on a physical quantity proportional to the power consumed by the speaker array when synthesizing a multi-sound field), etc.

[0203] Furthermore, in the above embodiment (including the modified examples), the case where information on multiple local sound fields is set by the local sound field setting unit 11 in the sound field control system 1000 has been described, but this is not limited to this, and the information on multiple local sound fields may be input and set from the outside (for example, from the outside via an external input interface), for example.

[0204] In addition, in the second embodiment, a case where analysis is performed using a two-dimensional cylindrical harmonic spectrum in the sound field control system 2000 has been described, but the present invention is not limited to this, and the method shown in the second embodiment may be applied using a three-dimensional spherical harmonic spectrum to perform sound field control using the sound field control system 2000.

[0205] Furthermore, in the sound field control system 1000 and sound field control device 100 described in the above embodiments (including modified examples), each block may be individually integrated into a single chip using a semiconductor device such as an LSI, or may be integrated into a single chip to include some or all of the blocks.

[0206] Although we refer to it as an LSI here, it may also be called an IC, system LSI, super LSI, or ultra LSI depending on the level of integration.

[0207] Furthermore, the method of integration is not limited to LSI, but may be realized by dedicated circuits or general-purpose processors. FPGAs (Field Programmable Gate Arrays), which can be programmed after LSI manufacturing, or reconfigurable processors, which allow the connections and settings of circuit cells within LSI to be reconfigured, may also be used.

[0208] Furthermore, part or all of the processing of each functional block in each of the above embodiments (including modified examples) may be realized by a program. And part or all of the processing of each functional block in each of the above embodiments is performed by a central processing unit (CPU) in a computer. Furthermore, the programs for performing each processing are stored in a storage device such as a hard disk or ROM, and are executed in the ROM or by being read into the RAM.

[0209] Furthermore, each process in the above-described embodiment (including modifications) may be realized by hardware, software (including cases where it is realized together with an OS (operating system), middleware, or a predetermined library), or may be realized by a combination of software and hardware.

[0210] For example, when each functional unit of the above embodiment (including the modified examples) is realized by software, each functional unit may be realized by software processing using the hardware configuration shown in FIG. 24 (for example, a hardware configuration in which a CPU, GPU, ROM, RAM, input unit, output unit, communication unit, memory unit (for example, a memory unit realized by an HDD, SSD, etc.), an external media drive, etc. are connected via a bus).

[0211] Furthermore, when each functional unit of the above embodiment (including modified examples) is realized by software, the software may be realized using a single computer having the hardware configuration shown in Figure 24, or may be realized by distributed processing using multiple computers.

[0212] Furthermore, the order of execution of the processing methods in the above embodiments (including modified examples) is not necessarily limited to that described in the above embodiments, and the order of execution can be changed within the scope of the gist of the invention.

[0213] The scope of the present invention includes a computer program for causing a computer to execute the above-described method, and a computer-readable recording medium having the program recorded thereon. Examples of computer-readable recording media include flexible disks, hard disks, CD-ROMs, MOs, DVDs, DVD-ROMs, DVD-RAMs, large-capacity DVDs, next-generation DVDs, and semiconductor memories.

[0214] The computer program is not limited to one recorded on the recording medium, but may be one transmitted via a telecommunications line, a wireless or wired communication line, a network such as the Internet, or the like.

[0215] Furthermore, in the description of this specification and the claims, "optimization" refers to achieving the best state, and a parameter for "optimizing" a system (model) refers to a parameter when the value of the objective function of the system is the optimal value. The "optimal value" is the maximum value when the system is in a better state as the value of the objective function of the system increases, and is the minimum value when the system is in a better state as the value of the objective function of the system decreases. The "optimal value" may also be an extreme value. The "optimal value" may also allow for a predetermined error (measurement error, quantization error, etc.), and may be a value within a predetermined range (a range that can be considered to have sufficiently converged).

[0216] The specific configuration of the present invention is not limited to the above-described embodiment (including modified examples), and various changes and modifications are possible without departing from the gist of the invention. [Explanation of symbols]

[0217] 1000, 2000 Sound Field Control System 100, 200 Sound field control device 11 Local sound field setting section 12 Local sound field decomposition processing section 13 Optimization processing section 14 Global sound field simultaneous reproduction processing section Spk_int Speaker array for internal sound field Spk_ext Speaker array for external sound field 21 Sound field setting processing section 22 Transfer function matrix setting processing section 23 Multiple diffusion component data acquisition processing unit 24 Speaker-to-control area transfer function acquisition processing section 25 Sound field reproduction processing section

Claims

1. a speaker group including a plurality of combinations of a cylindrical baffle and a plurality of speakers arranged on the circumference of the cylindrical baffle; a sound source unit that receives text or speech in a predetermined language, translates the text or speech into two or more languages, and outputs a plurality of voice signals that are not identical to each other; a sound field reproduction processing unit that receives an output from the sound source unit, drives the speaker group to form a plurality of sound areas, and reproduces the audio signals translated into the two or more languages ​​or the plurality of audio signals in each of the sound areas; A sound field control device comprising:

2. The sound field reproduction processing unit performs sound field control using a mode control method. The sound field control device according to claim 1.

3. A sound field control device that acquires data for performing sound field control taking into consideration mutual diffusion between the speakers of the speaker group and the baffle, a sound field setting processing unit that sets one or more sound field control target regions; (1) a first transfer function matrix is ​​set, which is a matrix of transfer functions between the baffles taking into account mutual diffusion; and (2) a transfer function matrix setting processing unit is set, which is a matrix of transfer functions between the speakers and the baffles taking into account diffusion by the speakers. a multiple diffusion component data acquisition processing unit that performs a matrix setting process taking multiple diffusion into consideration using the first transfer function matrix and the second transfer function matrix, and acquires multiple diffusion component data from the matrix acquired by the setting process; Furthermore, the sound field reproduction processing unit acquires a third transfer function, which is a transfer function between a speaker and a control target area, based on the multiple diffuse component data, and acquires a drive signal for driving each of the individual speakers of the speaker group by a weighted mode control method based on the acquired third transfer function and the output of the sound source unit. The sound field control device according to claim 2 .

4. A sound field control device that performs sound field control by a weighted mode control method in consideration of mutual diffusion between a cylindrical baffle and a plurality of speakers arranged on the circumference of the cylindrical buffer in an area where a plurality of speaker groups are arranged, the combination of the speakers being a cylindrical baffle and a plurality of speakers arranged on the circumference of the cylindrical buffer, a sound source unit that receives text or speech in a predetermined language, translates the text or speech into two or more languages, and outputs a plurality of voice signals that are not identical to each other; a sound field setting processing unit that sets one or more sound field control target regions; (1) a first transfer function matrix is ​​set, which is a matrix of transfer functions between the baffles taking into account mutual diffusion; and (2) a transfer function matrix setting processing unit is set, which is a matrix of transfer functions between the speakers and the baffles taking into account diffusion by the speakers. a multiple diffusion component data acquisition processing unit that performs a matrix setting process taking multiple diffusion into consideration using the first transfer function matrix and the second transfer function matrix, and acquires multiple diffusion component data from the matrix acquired by the setting process; a sound field reproduction processing unit that acquires a third transfer function, which is a transfer function between a speaker and a control target area, based on the multiplexed diffuse component data, and acquires a drive signal for driving each of the speakers of the speaker group by a weighted mode control method based on the acquired third transfer function and the output of the sound source unit; A sound field control device comprising:

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