WO2008001857A1

WO2008001857A1 - Spatial audio signal reproducing device and spatial audio signal reproducing method

Info

Publication number: WO2008001857A1
Application number: PCT/JP2007/063022
Authority: WO
Inventors: Itaru Kaneko
Original assignee: Toa Corporation
Priority date: 2006-06-30
Filing date: 2007-06-28
Publication date: 2008-01-03
Also published as: JP5543106B2; JPWO2008001857A1

Abstract

A spatial audio signal reproducing device for generating a loudspeaker sound to giving the listener a natural sense of presence compared with conventional reproducing methods. The spatial audio signal reproducing device (1) comprises reproduction space information acquiring means (4) for acquiring reproduction space information (11) on a preproduction space (23), transfer function generating means (6) for generating, from the reproduction space information (11), a transfer function (13) whose input is the input signal (14) inputted into a loudspeaker (8) and whose output is a reproduction space audio signal in a predetermined position of the reproduction space (23), and loudspeaker input signal generating means (7) for generating the input signal (14) inputted into the loudspeaker (8) in such a way that the difference between the reproduction space audio signal and the sound collection space audio signal (10) decreases by using the sound collection space audio signal (10) and the transfer function (13).

Description

Specification

Spatial audio signal reproduction apparatus and spatial audio signal reproduction method

[0001] The present invention relates to a spatial audio signal reproduction device and a spatial audio signal reproduction method for generating a speaker signal for approximately reproducing a spatial shape of a sound waveform in consideration of interference between speaker sounds and reflected sound. About. “Spatial audio signal” refers to a signal that has been processed in order to reproduce the actual performance sound, reflecting the spatial shape within a certain space.

Background art

Conventionally, a reproducing apparatus and a reproducing method using a plurality of speakers have been proposed. In general, using a larger number of channels is said to give a better sense of reality, so far, from mono to 2-channel stereo, from stereo to 5.1-channel stereo, and 7.1-channel surround, 7.2-channel The number of audio format channels tends to increase toward surround (see, for example, Patent Document 1). Recently, 22.2 channel surround system and 20 channel surround system have been proposed to obtain a richer sense of reality.

Patent Document 1: Japanese Patent Laid-Open No. 2005-236404

Disclosure of the invention

Problems to be solved by the invention

[0003] However, even if the number of channels is increased, the conventional playback method still leaves a large difference between the playback sound and the actual performance sound. For example, when the listening position is relatively close, it is easy to determine which sound is the actual performance sound by comparing the actual performance sound of the piano or guitar with the reproduced sound. This is mainly due to two factors.

[0004] The first factor is interference of a plurality of speaker sounds. For example, as shown in FIG. 11 (a), the performance sound 53 radiated from one trumpet 51 spreads in a spherical shape, and almost the same waveform can be observed at any point in space. On the other hand, the sound of trumpet 51 is recorded and stereo When playback is performed using two speakers 52 as in the method, as shown in FIG. 11 (b), sounds 54 having waveforms close to each other are radiated from the two speaker forces. Then, the sound of both speakers interferes at the listening position, and the waveform of the performance sound of the trumpet is deformed.

[0005] The second factor is sound reflection in the room. Sound is usually reflected with a reflectivity of 50% to 90% depending on the wall, ceiling, and floor. For this reason, when sound is reproduced from a single speaker in a rectangular parallelepiped room, the reflected sound of six-surface power can be heard at the same time. Usually, the listener can feel the spaciousness of the performance space by this reflected sound, and thus get a sense of reality. However, the reflected sound in the reproduction space is further added to the reproduced sound in the room. As a result, the listener can feel an unnatural feeling.

[0006] Accordingly, the present invention provides a spatial audio signal reproduction device and a spatial audio signal reproduction method that generate speaker sound that enables a listener to obtain a natural presence compared to conventional reproduction devices. Is an issue.

Means for solving the problem

In order to solve the above problems, a spatial audio signal reproduction device according to the present invention provides a spatial audio signal for reproducing a sound collection space audio signal in a sound collection space within a certain region near a predetermined position in the reproduction space. A reproduction device for obtaining reproduction space information related to the reproduction space, the reproduction space information including at least the information related to reflection in the reproduction space and information about a speaker position installed in the reproduction space. Based on the reproduction space information, information acquisition means, transfer function generation means for generating a transfer function that takes an input signal to the speaker as an input and outputs a reproduction space audio signal at a predetermined position in the reproduction space; and Based on the sound collection space audio signal and the transfer function, the difference between the reproduction space audio signal and the sound collection space audio signal is small. A loudspeaker input signal generating means for generating an input signal to the speaker so that, Ru with a (claim 1). According to the powerful configuration, an input signal to the speaker can be generated based on the information regarding the reflection in the reproduction space and the information on the speaker position.

[0008] The spatial audio signal reproduction device may further include listening position information acquisition means for acquiring listening position information relating to a listening position in the reproduction space, and the predetermined position in the reproduction space may be set as the listening position. (Claim 2). According to the powerful configuration, listening Corresponding to the position, an input signal to the speaker can be generated.

[0009] Further, in the spatial audio signal reproduction device, the listening position information is acquired every moment in the listening position information acquiring means, and the listening position information acquired every moment in the transfer function generating means. The transfer function may be generated every moment based on the position information, and the speaker input signal generation unit may generate an input signal to the speaker based on the generated transfer function. Claim 3). According to the configuration, even if the listening position changes, an input signal to the speaker is generated in response to the change.

[0010] Further, in the spatial audio signal reproduction device, an acoustic signal acquisition unit that acquires acoustic signals at a plurality of positions surrounding an arbitrary reference position in the sound collection space, and an acoustic signal acquired by the acoustic signal acquisition unit A reference position space audio signal calculating means for calculating a reference position space audio signal in a fixed region near the reference position based on the signal, and further comprising the reference position space audio signal as the sound collection space audio signal. (Claim 4). According to the powerful configuration, the sound collection space audio signal can be accurately acquired.

[0011] Further, in the spatial audio signal reproduction device, the listening position information acquisition unit may acquire listening position information related to the listening position in the playback space using a multi-view video stereoscopic recognition device. But (claim 5). According to the powerful configuration, the listening position can be grasped three-dimensionally.

[0012] Further, in the spatial audio signal reproduction device, the reproduction space information acquisition unit may acquire information related to reflection in the reproduction space using an acoustic room reflection measurement device (claim). Section 6). According to the powerful configuration, it is possible to acquire information related to reflection in the reproduction space without a video camera.

[0013] Further, in the spatial audio signal reproduction device, a charging unit that transmits a payment completion signal when the charging operation is completed, and a charging that determines whether or not charging has been performed based on the payment completion signal. Confirmation means, and when the charge confirmation means determines that the charge is not performed, the operation of the speaker input signal generation means is stopped, and the reproduction space information is obtained from the reproduction space information acquisition means. Via the Internet to the transfer function generating means The input signal to the speaker is sent from the speaker input signal generating means to the speaker via the Internet, and the settlement completion signal is sent from the charging means to the charging confirmation means via the Internet.請求 (Claim 7).

[0014] According to the configuration, even when the speaker input signal generating means and the reproduction space are far away from each other, the charging operation is performed, so that the input signal to the speaker is transmitted via the Internet. Can be sent to.

[0015] Furthermore, in order to solve the above-described problem, a spatial audio signal reproduction method according to the present invention is for reproducing a sound collection space audio signal in a sound collection space within a certain region near a predetermined position in the reproduction space. A spatial audio signal reproduction method for reproducing reproduction space information relating to the reproduction space, the reproduction space information including at least the information relating to reflection in the reproduction space and information about a speaker position installed in the reproduction space. A spatial information acquisition step, and a transfer function generation step for generating a transfer function based on the reproduction space information and using an input signal to the speaker as an input and outputting a reproduction space audio signal at a predetermined position in the reproduction space; and Based on the sound collection space audio signal and the transfer function, the difference between the reproduction space audio signal and the sound collection space audio signal is A speaker input signal generation step for generating an input signal to the speaker so as to be reduced (claim 8).

The invention's effect

[0016] According to the spatial audio signal reproduction device of the present invention, it is possible to generate a speaker signal in consideration of interference between speaker sounds and reflected sound. Therefore, it is possible to provide a spatial audio signal reproduction device and a spatial audio signal reproduction method that generate speaker sounds that enable the listener to obtain a natural sense of reality compared to conventional reproduction methods.

Brief Description of Drawings

FIG. 1 is a configuration diagram of a spatial audio signal reproduction device according to the present embodiment.

FIG. 2 is a diagram of an upward force of a microphone array for acquiring an acoustic signal that is useful in the present embodiment.

FIG. 3 is a schematic diagram of a reproduction space that is useful for this embodiment. FIG. 4 is a conceptual diagram comparing the case where the reference position space audio signal according to the present embodiment is not saved and the case where it is saved.

FIG. 5 is a plan view of a microphone for acquiring an acoustic signal that is effective in another embodiment.

FIG. 6 is a diagram for explaining the principle of an acoustic indoor reflection device according to another embodiment.

FIG. 7 is a diagram illustrating the principle of an acoustic room interior reflection device according to another embodiment.

FIG. 8 is a diagram showing an example of a speaker that works on the present embodiment.

9 is a diagram showing a state of sound wave propagation in the speaker of FIG.

FIG. 10 is a configuration diagram of a spatial audio signal reproduction device according to another embodiment.

[FIG. 11] A diagram showing a state of interference between speaker sounds, which is effective in the prior art.

BEST MODE FOR CARRYING OUT THE INVENTION

[0018] The best mode for carrying out the spatial audio signal reproduction device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of the spatial audio signal reproduction device 1. As shown in FIG. 1, the spatial audio signal reproduction apparatus 1 includes an acoustic signal acquisition means 2, a reference position space audio signal calculation means 3, a reproduction space information acquisition means 4, a listening position information acquisition means 5, and a transfer function generation. Means 6 and speaker signal generation means 7 are provided. Each means is described in detail below.

The acoustic signal acquisition unit 2 is a unit that acquires the acoustic signal 9 in the sound collection space. Here, the “acoustic signal” refers to a signal generated in space by the performance sound of a musical instrument or the voice of a person! In this embodiment, the performance sound (acoustic signal) 9 in the performance space (sound collection space) 20 is acquired. Specifically, a microphone array 21 is used as means for acquiring performance sound (acoustic signal) 9. FIG. 2 shows the microphone array 21 in the performance space (sound collection space) 20 as viewed from above. As shown in FIG. 2, the microphone array 21 includes eight microphones 22, and each microphone 22 is horizontally arranged on a circumference having a diameter Ll = 30 cm. However, the diameter L1 of the microphone array 21 is not limited to 30 cm, and any size can be used as long as the reference position space audio signal (performance waveform) 10 can be accurately calculated by the reference position space audio signal calculation means 3 described later. There may be. The performance sound 9 acquired by each microphone 22 is stored or used as pressure data. When the performance sound 9 is acquired, the performance space 20 on the wall or ceiling Reflected sound is also acquired. If the reflected sound in the performance space 20 can be accurately reproduced, the listener can obtain a natural sense of presence. The reason why the microphone array 21 includes a plurality of microphones 22 is that the spatial shape of the sound wave, for example, the traveling directions of various wave fronts constituting the sound wave, is more accurate than using a single microphone 22. This is because it can be calculated well.

[0021] The reference position space audio signal calculation means 3 sets an arbitrary point in the performance space 20 as a reference position 20a, and a performance waveform (reference position space audio signal, sound collection in a certain area near the reference position 20a. (Spatial audio signal) 10 is calculated. In the present embodiment, the spatial shape of the sound wave in the region inside the microphone array 21 is calculated. The performance waveform 10 near the reference position 20a in the microphone array 21 in the performance space 20 is calculated from the pressure data of the performance sound 9 acquired by the microphone mouthphone array 21 by the Kirchhoff integration formula. By using Kirchhoff's integral formula, the pressure (spatial waveform) at all points in the closed phase can be obtained by determining the pressure and flow velocity at each point on the closed surface. In the present embodiment, not all of the pressure and flow velocity at each point of the closed curved surface are determined, but it is assumed that the atmospheric pressure and the flow velocity change only in the horizontal direction, and that all sound sources are far away. For example, only 8 pressure points on the circumference can be calculated approximately. Then, the spatial shape of the sound wave in the inner region can be calculated with sufficient accuracy. Here, Kirchhoff's integral formula is shown in Equation 1. r is the position vector, p (r) is the pressure at the position r, r is the position vector representing the point on the flat surface S, i is the imaginary unit, and R is the distance from r to r. Here, r represents an arbitrary point in the closed phase to be integrated at a certain point. In the present invention, r represents an internal region surrounded by the microphone array 21. Therefore, Formula 1 shows that the atmospheric pressure at all points in the inner region surrounded by the microphone array 21, that is, the spatial shape of the sound wave, can also calculate the surrounding pressure and velocity force. The target for generating the speaker signal is to bring it close to the reference performance waveform within the fixed area obtained here.

[0022] [Equation 1]

3p, .e '

dn i The reproduction space information acquisition means 4 is a means for acquiring information (reproduction space information) 11 regarding the room (reproduction space) 23 in which the sound waveform is reproduced. In the present embodiment, information 11 on the three-dimensional shape of the room and the position of the speaker is acquired. FIG. 3 is a diagram schematically showing the reproduction space according to the present embodiment. As shown in Fig. 3, the three-dimensional shape of the room (reproduction space) 23 and the position of the speech force 24 are recognized three-dimensionally using the two video cameras 25. Is performed by the system. This recognition system is a known system, for example, a stereo labeling camera (registered trademark) manufactured by Cybers. If the three-dimensional shape of the room (reproduction space) 23 can be recognized, the reflection direction of the speaker sound can be estimated. Further, if the position of the speaker 24 can be recognized, the interference state between the speaker sounds can be estimated.

The listening position information acquisition means 5 is means for acquiring listening position information 12. In the present embodiment, the position of the listener's head (listening position) 30 (see FIG. 3) is instantly recognized by the two video cameras 25 used in the reproduction space recognition means 4 described above. Similarly to the above, if a plurality of video power cameras 25 are used, the position 30 of the listener's head can be recognized three-dimensionally. Also, instead of the video camera 25, it is possible to detect the position 30 of the listener's head by using an optical sensor V. By recognizing the listening position 30, it is possible to estimate the state of interference between the speaker sound and the reflected sound at the listening position 30.

[0025] The transfer function generation means 6 is a means for generating a transfer function 13 that receives the speaker input signal 14 and outputs a reproduction waveform (reproduction spatial audio signal) at the listening position 30. This reproduced waveform is a sound in which a plurality of speaker sounds and reflected sounds are overlapped. Assuming that the input signal is x, the reproduced sound at the listening position 30 is y, and the transfer function is H, these relations are as shown in Equation 2. In this embodiment, the transfer function 13 is generated by simulating the propagation of sound in the reproduction space (room) 23. There are various methods for simulating the propagation of sound. For example, assuming that the sound of a speaker is a perfect point sound source (sound radiated in a single-point force spherical shape), it can be obtained by simple calculation. . In addition, for example, Pose's Modeler (registered trademark) is an example of existing advanced simulation software that can perform more advanced simulations to obtain characteristics that are closer to reality. In this simulation method, the shape and size of the reproduction space obtained by the reproduction space information acquisition means 4 and the position of the speaker (reproduction space information 11), and the listening position (listening position information 12) obtained by the listening position information acquisition means 5 are used. ) Are automatically input, and the transfer function 13 is generated. Since the listening position (listening position information 12) changes every moment, the transfer function 13 is also generated every moment accordingly.

[0026] [Equation 2] y = Hx (Formula 2)

[0027] When only one speaker waveform in the reproduction space is obtained by the above simple simulation with one speaker, the transfer function is expressed by Equation 3. The number of rows in the H time period is determined by how many points on the reproduction space 23 the transfer function is included in H, and the number of columns is determined by the number of spinning forces. By arbitrarily increasing the number of rows of H, the transfer function 13 of the playback waveform at each arbitrary point in the playback space 23 can be expressed.

[0028] [Equation 3] e- ^{i2x! V} (Formula 3)

[0029] The speaker input signal generation means 7 is a speaker input signal that causes the reproduction waveform (reproduction space audio signal) at the listening position 30 to be closest to the performance waveform (reference position space audio signal) 10 at the reference position 20a. Is a means of generating 14. If the difference between the playback waveform at the listening position 30 and the performance waveform at the reference position 20a is E, then the playback waveform at the listening position 30 is y, and the performance waveform force ¾ at the reference position 20a is Can be expressed. When E ² approaches 0, the reproduced waveform at the listening position 30 and the performance waveform at the reference position 20a become closer.

[0030] [Equation 4] E ² (Formula 4)

[0031] Substituting Equation 2 into Equation 4 gives Equation 5. From this equation 5, the speaker input signal X that minimizes E ² is obtained.

[0032] [Equation 5]

E ²

(Formula 5)

In the present embodiment, the speaker input signal X is obtained using the least square method. As already described, the transfer function 13 can be obtained by the transfer function generation means 6 and the performance waveform 10 in the space including the reference position 20a can be obtained by the reference position space audio signal calculation means 3. Specifically, if there are two speakers and the error of the playback waveform is evaluated at three points in the playback space, H becomes 3 X 2D, and H can be expressed as Equation 6. If u is three-dimensional, u can be expressed as Equation 7. Then, when the speaker input signal X is expanded by the least square method, Equation 8 is obtained. Substituting each value into Equation 7 gives the speaker input signal X. When this speaker input signal is input to the speaker, a sound closest to the performance sound at the reference position 20a is generated at the listening position 30 under the condition of the reproduction space where the speaker is arranged. If there are ₁₀ reference points in the reproduction space in the speaker power book, the same calculation can be executed with H as 10 rows and 8 columns.

[0034] [Equation 6]

W: = [[Λ〃, hi 2 \ [2 /, h22 [h3 !, 32]] (Formula ₆ )

[0035] [Equation 7] u = [ul, uZ a3] (Formula 7)

[0036] [Equation 8]

X =

8)

[0037] Further, the performance waveform (reference position space audio signal) 10 near the reference position 20a of the performance space (sound collecting space) 20 may be stored once by the storage means 15, or the speaker input signal is generated as it is. You may make it send to the means 7. FIG. 4 is a conceptual diagram comparing the case where the performance waveform (reference position space audio signal) 10 is not saved with the case where it is saved. As shown in Fig. 4 (a), if the performance waveform (reference position space audio signal) 10 in the sound collection space 20 is sent to the reproduction space 23 (speaker input signal generation means 7) without being saved, it is collected. It is possible to enjoy the performance in real time in the playback space 23 away from the sound space 20. On the other hand, as shown in Fig. 4 (b), if the performance waveform (reference position space audio signal) 10 in the sound collection space 20 is saved by the storage means 15, the performance waveform (reference frequency) in the playback space 23 even after the performance. (Position space audio signal) 10 can be reproduced. Instead of storing the performance waveform (reference position spatial audio signal) 10 by the storage means 15, the performance sound (acoustic signal) 9 may be stored by the storage means 15. In this case, it is necessary to calculate the performance waveform (reference position space audio signal) 10 during reproduction in the reproduction space 23.

In the foregoing, the spatial audio signal reproduction device 1 according to an embodiment of the present invention has been described. In this embodiment, a spatial waveform (performance waveform) of sound waves is acquired, and a reproduction waveform that is as close as possible to the performance waveform can be generated at the listening position 30 while considering the state of the reproduction space. . Therefore, according to the spatial audio signal reproduction device that is useful in this embodiment, If this is the case, the listener can obtain a natural sense of reality compared to the conventional reproduction method.

In the above, the listening position (listening position information 12) acquired by the listening position information acquisition means 5, the shape and dimensions of the reproduction space acquired by the reproduction space information acquisition means 4, and the position of the speaker (reproduction space information 11) Based on the above, the explanation has been given on the calculation of the transfer function with the input signal to the speaker as the input and the playback spatial audio signal at the listening position as the output. However, the transfer function is not necessarily obtained based on the listening position. There is no need. For example, the transfer function may be calculated using the center position (predetermined position) of the reproduction space instead of the audience position. That is, a transfer function may be calculated in which the input signal to the speaker is input and the reproduction space audio signal is output at the center position (predetermined position) of the reproduction space. According to the powerful configuration, an input signal to the speaker can be generated with a simpler configuration.

[0040] Further, in the above, the force obtained by simulation of the transfer function may be obtained by measurement using a microphone. FIG. 5 is a view showing the arrangement of the microphones 26, where (a) is a plan view and (b) is a side view. As shown in FIG. 5, eight-point microphones 26 are arranged on a circumference having a diameter L2 = 60 cm, and each microphone 26 obtains pressure data. Using this pressure data, the reproduced sound at the position 30 of the listener's head is calculated. The calculation method uses the Kirchhoff integration formula shown in Equation 1 above. The listener's head position 30 must be within the circumference of the microphone. Otherwise, the reproduced sound at the listening position 30 cannot be calculated accurately. In addition, since the speaker signal used for this measurement can be used as input data for calculation, the transfer function H can be calculated by substituting into Equation 2 and performing reverse calculation.

[0041] In the above description, the case where the three-dimensional shape of the room and the speaker position are recognized using two video cameras and a recognition system as the reproduction space information acquisition means has been described. A reflection measuring device may be used. An acoustic room reflection measurement device is a device that adds a microphone to each of a plurality of speakers used for reproduction, and uses these to measure and estimate the room shape and reflection characteristics. The transmission characteristics between the listening position and the speaker are two: a sound that directly reaches the listening position from a force, that is, a transmission characteristic that corresponds to the direct sound, and a transmission characteristic that corresponds to a reflected wave from each wall in the room, that is, an indirect sound. Component power also becomes. Directly The sound can be estimated only for the positional relationship between the speaker and the listening position, regardless of the shape of the room. Indirect sound can be calculated from the shape of the room, the reflectance, the listening position in the room, and the speaker position. Therefore, if the approximate shape of the room and the reflection characteristics of each wall, floor, and ceiling are acquired as data, the necessary transfer characteristics can be calculated. Therefore, the acoustic indoor reflection measurement device uses the fact that the room is usually close to a rectangular parallelepiped, and estimates the position and reflection characteristics of each wall using a fixed spin force and several microphones.

Specifically, several methods can be considered, but the simplest method will be described below. Here, eight speakers are used, and each of the eight speakers is equipped with a microphone! Then, test signals are output from each speaker, received by a microphone connected to another speaker, and the impulse response is calculated. FIG. 6 is a diagram schematically showing the state of impulse response propagation from the first speaker 28 to the second speaker 29 in a rectangular parallelepiped room. As shown in FIG. 6, the impulse response from the first speaker 28 to the second speaker 29 includes many impulse-shaped peaks (hereinafter referred to as peak components) having different delay times depending on the path. Here, t (n, m, 0) is the shortest delay component from the peak power to the mth speaker, and the delay time (n, m, l), ..., t (n, m, 8). FIG. 7 shows the peak components of the impulse response from the first speaker 28 to the second speaker 29, where the horizontal axis represents the delay time and the vertical axis represents the magnitude of the peak component. In Fig. 7, the shortest delay time t (1,2,0) is considered to be the delay time of the sound directly propagated between the speakers. For the other peak components, the peak component with the shortest delay time is considered to be reflected from the wall. Then, if 8 speakers are used, 8 x 7 = 56 t (n, m, 0) are obtained, and half of them are the reverse propagation of the same speaker pair and the same delay time. The distance between each pair of speakers can be calculated back from 28 independent delay times. As a result, the relative arrangement of the speakers can be calculated with high probability and high accuracy. In addition, it can be used to estimate the positional relationship between the speaker and the wall, ceiling, or floor from other non-shortest delay times. For example, if t (l, 2,0) is 6.6 ms and t (l, 2, l) is 10 ms, the linear distance from the first speaker 28 to the second speaker is the sound speed X 0.0066 = about 2 m. Most recently, the path of the reflected wave from the wall is t (l, 2, l) X sound velocity = 0.01 X sound velocity = about 3 m. And straight Since it can be expected that 8 X 56/2 = 224 delay times due to reflected waves other than the contact sound can be obtained, it is possible to estimate the positional relationship between the ceiling, wall, floor and speaker. Of these, many delay times are considered to be unclear due to noise, etc. If most of the delay times are obtained, the objective is sufficiently achieved.

[0043] It should be noted that in the case of reproduction by the spatial audio signal reproduction device 1 according to the present embodiment, it is desirable to arrange the speaker so that the reflected sound becomes smaller than the speaker sound. This is because the reflected sound may not be completely erased. For example, it is desirable to place the speaker near the listening position. When the path from the sound reflected to the wall to reach the listening position is four times that of the direct sound, the reflected sound is attenuated to 1/16 of the direct sound pressure.

FIG. 8 is a diagram showing an embodiment of a speaker. As shown in FIG. 8, the speaker 33 may be suspended from the ceiling 31 by a support column 32, and the columnar speaker 33 may be equipped with a number of drivers 34 around it. FIG. 9 is a diagram illustrating the propagation state of the sound wave 35 in a state where the polarity, amplitude, and delay time are adjusted to the multiple drivers 34 of the speaker 33 of FIG. 8 and different signals are input thereto. As shown in Fig. 9, when a signal adjusted for the purpose of polarity, amplitude, and delay is input to each driver 34, a certain direction (direction A, B) is set so that the sound wave 35 is not emitted. Can be adjusted. If the direction in which no sound is emitted is placed on the wall side, the reflected sound can be reduced. However, in this case, it is necessary to consider the above characteristics of the speaker when calculating the transfer function.

[0045] Further, each configuration is made up of a value-added server 41 in which the service provider has installed the spatial audio signal playback device 1 described above and a playback client device 42 used by a service user interconnected by the Internet 45. You may make it divide. FIG. 10 is a diagram showing the relationship between the value-added value server 41 and the playback client device 42. Since the configuration shown in Fig. 10 has many similarities to the configuration shown in Fig. 1 already described, each means will be briefly described here. As shown in FIG. 10, the value-added server 41 includes an acoustic signal acquisition unit 2, a reference position space audio signal calculation unit 3, a transfer function generation unit 6, a speaker input signal generation unit 7, and a billing confirmation unit 14 And. On the other hand, the reproduction client device 42 includes reproduction space information acquisition means 4, listening point position information acquisition means 5, a speaker 8, and a billing means 43. [0046] The acoustic signal acquisition means 2 on the value-added server 41 side acquires the acoustic signal (performance sound) 9 in the performance space (sound collection space) 20, and calculates the reference position space audio signal based on this. The means 3 calculates a reference position space audio signal (a performance waveform near the reference position 20a) 10. On the other hand, the reproduction space information acquisition means 4 and the listening point position information acquisition means 5 on the reproduction client device 42 side respectively receive the reproduction space information 11 and the listening point position information 12 on the value added server 41 side via the Internet 45. To the transfer function generation means 6 of The transfer function generation means 6 calculates a transfer function 13 based on the reproduction space information 11 and the listening point position information 12. The speaker input signal generation means 7 on the value-added server 41 side generates the speaker input signal 14 based on the reference position spatial audio signal 10 and the transfer function 13, and the playback client device 42 side via the Internet 45 Sent to speaker 8. The operation so far is the same as that described in the above embodiment except that signals are exchanged via the Internet. However, after the charging means 43 on the playback client device 42 side performs the charging operation, a payment completion signal 46 is sent via the Internet 45. If this payment completion signal 46 is not confirmed by the charge confirmation means 44 on the value added server 41 side, the speaker input signal 14 does not operate. When the payment completion signal 46 is confirmed by the billing confirmation means 44, the permission signal 47 is sent to the billing confirmation means 44 force S speaker input signal generation means 7, and this permission signal 47 is received by the speaker input signal generation means 7. At that time, the speaker input signal 14 is sent to the playback client device 42 side. The billing unit 43 collects and confirms the price according to the playback piece, the number of playbacks, and the playback time, and controls the function of the value-added server 41 to operate only when charging is performed correctly. It is obvious that such a billing means 43 is realized by pay broadcasting or the like and can be easily realized. In addition, the confirmation signal of whether or not the billing has been normally performed can be safely transmitted by a normal PKI (public key infrastructure), and the value-added server 41 can be controlled to operate only when a genuine billing signal is given. It is clear.

[0047] The conventional recording / playback method has a drawback that it is always possible to make an illegal copy by recording the output as it is. For example, if the playback sound from a speaker was recorded as it was, a copy could be created. However, as described above, if the spatial audio signal reproduction device according to the present embodiment is operated via the Internet, a “specific reproduction” is performed. If it is played back with high quality only in the `` environment '' and `` specific listening position '', there is a characteristic that even if it is simply recorded and played, the same service quality can be obtained. Can not. Therefore, unauthorized copying can be prevented.

[0048] From the above description, many modifications and other embodiments of the present invention are apparent to persons skilled in the art. Accordingly, the foregoing description should be construed as illustrative only and is provided for the purpose of teaching those skilled in the art the best mode of carrying out the invention. Details of the structure and Z or function thereof can be substantially changed without departing from the spirit of the invention.

Industrial applicability

[0049] According to the present invention, it is possible to generate a speech force signal in consideration of interference between speaker sounds and reflected sound at the listening position. Therefore, it is useful for the audio technical field, especially in the spatial audio signal reproduction technical field.

Claims

The scope of the claims

[1] A spatial audio signal reproduction device for reproducing a sound collection space audio signal in a sound collection space within a certain region near a predetermined position in a reproduction space,

Reproduction space information acquisition means for acquiring reproduction space information relating to the reproduction space, the reproduction space information including at least the information relating to reflection in the reproduction space and information on a speaker position installed in the reproduction space;

Transfer function generating means for generating a transfer function based on the reproduction space information and having an input signal to the speaker as an input and an output of a reproduction space audio signal at a predetermined position in the reproduction space;

Speaker input signal generation means for generating an input signal to the speaker based on the sound collection space audio signal and the transfer function so that a difference between the reproduction space audio signal and the sound collection space audio signal is reduced. And a spatial audio signal reproduction device.

[2] The spatial audio signal according to claim 1, further comprising listening position information acquisition means for acquiring listening position information relating to a listening position in the reproduction space, wherein the predetermined position in the reproduction space is the listening position. Playback device.

[3] The listening position information acquisition means acquires the listening position information every moment,

In the transfer function generating means, based on the listening position information acquired every moment, the transfer function is generated every moment,

3. The spatial audio signal reproduction device according to claim 2, wherein the speaker input signal generation means generates an input signal to the speaker based on the transfer function generated every moment.

[4] acoustic signal acquisition means for acquiring acoustic signals at a plurality of positions surrounding an arbitrary reference position in the sound collection space;

Reference position space audio signal calculation means for calculating a reference position space audio signal in a certain region near the reference position based on the sound signal acquired by the sound signal acquisition means;

The spatial audio signal reproduction device according to any one of claims 1 to 3, wherein the reference position spatial audio signal is the sound collection spatial audio signal.

Corrected urn (Rule 91)

[5] The listening position information relating to the listening position in the reproduction space is acquired by the listening position information acquisition means using a multi-view video stereoscopic recognition device. The spatial audio signal reproducing device according to any one of the above items.

[6] The spatial audio according to any one of claims 1 to 5, wherein the reproduction space information acquisition means acquires information related to reflection in the reproduction space using an acoustic room reflection measurement device. Signal reproduction device.

[7] Billing means for transmitting a payment completion signal when the billing operation is completed;

Charging confirmation means for determining whether or not charging has been performed based on the settlement completion signal; and

If it is determined that charging has not been performed, the charging confirmation unit stops the operation of the speaker input signal generation unit,

The reproduction space information is sent from the reproduction space information acquisition means to the transfer function generation means via the Internet,

An input signal to the speaker is sent from the speaker input signal generating means via the speaker Internet,

The spatial audio signal reproduction device according to any one of claims 1 to 6, wherein the settlement completion signal is also sent to the billing confirmation unit via the Internet.

[8] A spatial audio signal reproduction method for reproducing a sound collection space audio signal in a sound collection space within a certain region near a predetermined position in a reproduction space,

A reproduction space information acquisition step for acquiring reproduction space information relating to the reproduction space, the reproduction space information including at least the information relating to reflection in the reproduction space and information on a speaker position installed in the reproduction space;

A transfer function generation step of generating a transfer function based on the playback space information and having an input signal to the speaker as an input and an output of a playback space audio signal at a predetermined position in the playback space;

Based on the sound collection space audio signal and the transfer function, the input signal to the speaker is reduced so that the difference between the reproduction space audio signal and the sound collection space audio signal is reduced. A spatial audio signal reproduction method comprising: a speaker input signal generation step of generating.