Technical field
[0001]
　This technique is a signal processing apparatus and method, and a program, the signal processing apparatus and method capable of reproducing different sounds at the far and near, and a program.
BACKGROUND
[0002]
　Conventionally, a technique for forming a locally sound field using a speaker is known.
[0003]
　For example, a local sound field techniques have been proposed by the super-directional control using a parametric speaker as such techniques (e.g., see Non-Patent Document 1).
[0004]
　Further, for example, by generating an evanescent wave with a speaker array, a technique for forming a listening sound field capable of sound only in the speaker array near also been proposed (e.g., see Patent Document 1).
[0005]
　By the way, in public places such as airports and train stations, flight information and signage using the video display is presented. By using the audio added to the picture, but it is possible to present the content more effectively, so that the sound will reachable on the one hand to its information it does not require an unspecified number of people.
[0006]
　Therefore, for example, only the minimum information is presented to a distant person, such as to be able to provide detailed information to people in the vicinity, to be able to play different sounds at the far and near it is convenient. For example, in the bank of a cash dispenser, and a voice you want to hear only the people you are working in a cash dispenser the vicinity, there is a voice you want to hear in the distance of people, such as "There is a thing left behind."
CITATION
Non-patent literature
[0007]
Non-Patent Document 1: Kamakura other, "practical use of the parametric speaker," Acoustical Society of Japan Journal, vol.62, p.791-797, 2006.
Patent Document
[0008]
Patent Document 1: JP 2012-44572 JP
Summary of the Invention
Problems that the Invention is to Solve
[0009]
　However, in the above-described technology, it has been difficult to reproduce different sounds in the distant region and the neighboring region.
[0010]
　This technology has been made in view of such circumstances, it is to be able to play different sounds at the far and near.
Means for Solving the Problems
[0011]
　Signal processing apparatus according to an embodiment of the present technology, by performing filtering using a far sound reproduction filter coefficient for the first sound source signal, generating a distant sound reproduction signal for reproducing sound in the far listening area and far filter unit which, by performing a filtering process using the near sound reproducing filter coefficients for the second sound source signal, near sound reproducing signal for reproducing sound in different neighborhood listening region and the far listening area and a neighborhood filter unit for generating a.
[0012]
　The near sound reproducing signal may be a signal for generating the evanescent wave.
[0013]
　The signal processing unit, wherein further provided near sound field processing unit for determining the attenuation factor of the evanescent wave in accordance with a boundary position between the far listening area and the vicinity listening area, to the vicinity of the filter unit, a plurality of the it is possible to perform the filter processing using the neighborhood sound reproduction filter coefficient corresponding to the attenuation factor determined within the vicinity sound reproducing filter coefficients.
[0014]
　Signal to the processor, said further provided near sound field processing unit for determining the position of the control point in response to the boundary position between the far listening area and the vicinity listening area, wherein the vicinity of the filter unit, a plurality of the neighboring sound it is possible to perform the filter processing using the neighborhood sound reproduction filter coefficient corresponding to the position of the control points determined of the reconstruction filter coefficients.
[0015]
　Signal to the processor, said further provided a far sound field processing unit for determining the position of the control point in response to the boundary position between the far listening area and the vicinity listening area, wherein the distal filter section, a plurality of the distant sound it is possible to perform the filtering process using the distant sound reproduction filter coefficient corresponding to the position of the control points determined of the reconstruction filter coefficients.
[0016]
　The distant sound reproduction signal may be a signal for generating the propagating wave.
[0017]
　The signal processing apparatus, the first sound source signal or the distant sound based on the far sound field processor, determined the gain determines the gain depending on the boundary position between the far listening area and the vicinity listening area It may further include a distal gain adjustment section for performing gain adjustment of the reproduced signal.
[0018]
　The signal processing unit, the second sound source signal or the near sound on the basis of the near sound field processor, determined the gain determines the gain depending on the boundary position between the far listening area and the vicinity listening area It may further include a near gain adjustment section for performing gain adjustment of the reproduced signal.
[0019]
　And said first sound signal and the second sound source signal can be a signal for reproducing sound having different contents.
[0020]
　The signal processing apparatus may further include a speaker array for reproducing sound based on a signal obtained by combining the near sound reproducing signal and the far sound reproduction signal.
[0021]
　The signal processing device can be a first speaker array for reproducing sound, further provided with a second speaker array for reproducing sound based on the proximity sound reproduction signal based on the distant sound reproduction signal.
[0022]
　Sound based on the distant sound reproduction signal, it is possible to be played at a timing different from that of the sound based on the proximity sound reproduction signal.
[0023]
　A sound based on the distant sound reproduction signal can be a sound masking sound based on the proximity sound reproduction signal.
[0024]
　The signal processing apparatus may further include a sound field boundary control unit which determines the boundary position between the far listening area and the vicinity listening area based on the listener's position in space.
[0025]
　Signal processing method or a program according to an embodiment of the present technology, by performing filtering using a far sound reproduction filter coefficients for the first sound source signal, the far sound reproduction signal for reproducing sound in the far listening area generates, by performing the filtering process using the near sound reproducing filter coefficients for the second sound source signal, generating a near sound reproducing signal for reproducing sound in different neighborhood listening region and the far listening area including the step of.
[0026]
　In one aspect of the present technology, by performing the filtering process using the distant sound reproduction filter coefficients for the first sound source signal, the far sound reproduction signal for reproducing sound in the far listening area is created, the by performing the filtering process using the near sound reproducing filter coefficients for the second sound source signal, near sound reproducing signal for reproducing sound in different neighborhood listening region and the far listening area is created.
Effect of the invention
[0027]
　According to the embodiments of the present technology, it is possible to play different sounds at the far and near.
[0028]
　Here, the advantages described in the present invention is not necessarily limited, it may be any of the effects described in the present disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029]
[1] is a diagram for explaining the technology.
FIG. 2 is a diagram for explaining the technology.
Is a diagram illustrating a configuration example of FIG. 3 perspective Betsuoto field forming apparatus.
Is a diagram illustrating FIG. 4 coordinate system.
Is a diagram for describing the control of FIG. 5 sound field boundary position.
Is a diagram for describing the control of FIG. 6 sound field boundary position.
Is a diagram for describing the control of FIG. 7 sound field boundary position.
8 is a flowchart illustrating a perspective Betsuoto field forming process.
Is a diagram illustrating a configuration example of FIG. 9 perspective Betsuoto field forming apparatus.
It is a flow chart illustrating the FIG. 10] Perspective Betsuoto field generation process.
11 is a diagram showing a configuration example of a computer.
DESCRIPTION OF THE INVENTION
[0030]
　Hereinafter, with reference to the accompanying drawings, a description will be given of an embodiment according to the present technology.
[0031]

　This technique, using a speaker array, is to be able to play different sounds at the far and near.
[0032]
　In this technique, for example two of the sound field by one of the speaker array obtained by arranging a plurality of speakers linearly it is formed at the same time.
[0033]
　In this case, the speaker array, speaker array near the region at only the sound listening capable sound field (hereinafter, referred to as near sound reproducing sound field) and the sound field capable listening sound in the distance away from the speaker array (hereinafter, referred to as a distant sound reproduction sound field) and are formed simultaneously.
[0034]
　Here, near the sound reproduction sound field is formed, for example by reproducing a sound based on the proximity sound reproduction signal for generating an evanescent wave. Note that the evanescent waves, a wave having a property of exponentially sound pressure in a direction perpendicular to the speaker array is distance attenuation.
[0035]
　Such near sound reproducing sound field by evanescent waves is kept sufficient sound pressure listening only in the vicinity of the speaker array, steeply sound pressure in the distance has become a sound field to decay.
[0036]
　In contrast, the distant sound reproduction sound field is formed by reproducing a sound based on the distant sound reproduction signal to generate a propagating wave to propagate longer distance such as a plane wave or a spherical wave. Incidentally, the distant sound reproduction sound field is below, the description will be continued as being formed by a plane wave.
[0037]
　Such propagating wave distant sound reproducing sound field by has a sound field sufficient sound pressure listening is maintained even in distant away from the speaker array.
[0038]
　Therefore, such a near sound reproducing sound field and the far sound reproduction sound field formed at the same time, and in the vicinity speaker array is sufficiently large reproduced than the sound of distant sound reproduction sound field sound near sound reproducing sound field by the so that it is possible to play different sound the neighborhood and distant speaker array.
[0039]
　In this case, the wave front of the reproduced sound is as shown in Figure 1, for example. Incidentally, in FIG. 1, the vertical direction and the horizontal direction represents the direction in space, shading at the portion indicated by the arrow Q11 indicates the amplitude of the wavefront of the reproduced sound.
[0040]
　In this example are disposed one linear loudspeaker array at the position indicated by the arrow A11, by the linear loudspeaker array, sound based on the proximity sound reproduction signal (hereinafter, also referred to as the neighborhood sound) and sound based on the distant sound reproduction signal (hereinafter, also referred to as distant sound) and is reproduced at the same time. That is, the near sound reproducing sound field and far sound reproduction sound field is formed at the same time.
[0041]
　Here, near the sound is evanescent wave, so far sound is a plane wave, those waves spatiospectral, that is, the waves of different regions in space-time spectrogram without interfering with each other, the listener and the neighboring sound it is possible to discern the distant sound.
[0042]
　Also, listening in this case, the sound pressure is as shown by the arrow Q12 at each spatial position, the linear loudspeaker listening area LE11 next array near vicinity sound region distant sound which is located away from the straight line speaker array a region LE12. Incidentally, shading at each position in a portion indicated by the arrow Q12 indicates the sound pressure at those locations.
[0043]
　In this example, the vicinity of the listening area LE 11, mutually different regions of distant listening area LE12, different sounds, respectively, are reproduced.
[0044]
　When multiple speakers are a direction perpendicular to the direction alongside the y-direction which constitutes the linear loudspeaker array, the sound pressure of the sound pressure and far sound near sound is attenuated as shown in FIG. 2, for example with respect to the y-direction, respectively . The vertical axis in FIG. 2 shows the sound pressure and the horizontal axis represents the position in the y-direction.
[0045]
　In Figure 2, the straight line L11 shows the sound pressure in the vicinity of sound at each position in the y-direction, the sound pressure indicated by the straight line L11 is the distance in the y direction from the linear loudspeaker array and y 1 / e y and Become. In contrast, the curve L12 indicates a sound pressure of a distant sound at each position in the y-direction, the sound indicated by the curve L12 pressure, when the distance in the y direction from the linear loudspeaker array and y and 1 / y Become.
[0046]
　Therefore, listening is region R11 sound pressure in the vicinity of sound is greater than the distant sound, the next listening area LE11 shown in FIG. 1, the region R12 sound pressure of the distant sound is greater than in the vicinity sound shown in FIG. 1 in space a region LE12.
[0047]
　For example, in region R11, sounds to be listener distant sound not only near sound, it is possible to sufficiently increase the sound pressure in the vicinity of sound and far sound, the listener so far sound heard sufficiently small it is possible to. Further, in the region R12, a large attenuation in the vicinity of sound, the listener so that the only distant sound is heard.
[0048]
　Thus, by utilizing the evanescent wave and plane wave way of damping are different from each other in the y-direction, mainly the region R11 where near you hear the listener, distant sound is formed and a region R12 audible to the listener it becomes possible.
[0049]
　Hereinafter, the boundary position of the region R11 and the region R12, that is, with the sound pressure in the vicinity of sound and far sound the position of the same level (magnitude) and a y-direction, also referred to as sound field boundary position.
[0050]

　Now, hereinafter, be described with reference to certain exemplary embodiments than the present technology.
[0051]
　Figure 3 is a diagram showing a configuration example of an embodiment of a perspective Betsuoto field forming device employing the present technology.
[0052]
　Perspective Betsuoto field forming apparatus 11 shown in FIG. 3 is a signal processing apparatus for reproducing different sounds at the far and near. Perspective Betsuoto field forming apparatus 11, the far sound field processing unit 21, the gain adjusting unit 22, the filter unit 23, near the sound field processor 24, a gain adjustment section 25, the filter unit 26, an addition section 27 and the speaker array 28, It has.
[0053]
　In perspective Betsuoto field generating device 11, relative to the far sound field processor 21 and the near sound field processor 24, the boundary position between the near sound reproducing sound field and far sound reproduction sound field, i.e. in the vicinity of sound listening region and far control information for controlling the sound field boundary position is a boundary position between the listening area of ​​the sound is supplied.
[0054]
　For example, the control information includes listener position information indicating the position of the listener in the space, are like sound field boundary position information indicating the position of the boundary. Incidentally, the boundary position information may be one that is manually entered, or may be predetermined.
[0055]
　Far sound field processing unit 21 determines a sound field boundary position based on the supplied control information. Far sound field processor 21, sound field boundary control unit 41, and a distant sound reproduction filter coefficient recording unit 42 and the filter coefficient selector 43,.
[0056]
　Sound field boundary control unit 41 determines a sound field boundary position based on the supplied control information, the gain adjusting unit 22 determines the gain values ​​for gain adjustment of distant sound based on the determination result supplies. Hereinafter, the gain values ​​for gain adjustment of distant sound, also referred to as particular distant sound gain value.
[0057]
　Also, the sound field boundary control unit 41, based on the determination result of the sound field boundary position, appropriate far sound reproducing filter from a plurality of distant sound reproducing filter coefficient recorded in the distant sound reproducing filter coefficient recording unit 42 It generates a distant sound reproduction filter coefficient selection information for selecting the coefficients and supplies the filter coefficient selection unit 43.
[0058]
　Distant sound reproducing filter coefficient recording unit 42 in advance plural records the distant sound reproduction filter coefficients is an acoustic filter coefficients for forming a far sound reproduction sound field on the far side from the speaker array 28 than the predetermined sound field boundary position and which supplies the distant sound reproduction filter coefficients recorded in a filter coefficient selecting unit 43.
[0059]
　Filter coefficient selection unit 43 based on the sound field boundary distant sound reproducing filter coefficient selection information supplied from the control unit 41, among a plurality of distant sound reproducing filter coefficient recorded in the distant sound reproducing filter coefficient recording unit 42 select one distant sound reproducing filter coefficients from and supplies to the filter unit 23.
[0060]
　Gain adjusting unit 22, based on the sound field boundary distant sound gain value supplied from the control unit 41 performs gain adjustment for the supplied sound signal, and supplies the sound source signal obtained in the filter unit 23. Sound source signal to be supplied to the gain adjusting unit 22, an acoustic signal in the time domain for reproducing far sound.
[0061]
　Filter unit 23, to the excitation signal supplied from the gain adjustment unit 22, generates a distant sound reproduction signal by performing filtering using a far sound reproduction filter coefficients supplied from the filter coefficient selecting unit 43, It is supplied to the adder 27. In the filter unit 23, as filtering, convolution processing is performed convolving the sound source signal and far sound reproducing filter coefficients.
[0062]
　Near sound field processing unit 24 determines a sound field boundary position based on the supplied control information. Near sound field processor 24, sound field boundary control unit 51, and a near sound reproducing filter coefficient recording unit 52 and the filter coefficient selector 53,.
[0063]
　Sound field boundary control unit 51, and determines the sound field boundary position based on the supplied control information, the gain adjusting unit 25 determines the gain values ​​for gain adjustment in the vicinity of sound based on the determination result supplies. Hereinafter, the gain values ​​for gain adjustment in the vicinity of sound, referred to in particular also the neighboring sound gain value.
[0064]
　Also, the sound field boundary control unit 51, based on the determination result of the sound field boundary position, appropriate near sound reproducing filter from a plurality of neighboring sound reproducing filter coefficient recorded in the vicinity of sound reproduction filter coefficient recording unit 52 It generates a neighborhood sound reproduction filter coefficient selection information for selecting the coefficients and supplies the filter coefficient selector 53.
[0065]
　Near sound reproducing filter coefficient recording unit 52 in advance plural records the vicinity sound reproduction filter coefficients is an acoustic filter coefficients for forming a near sound reproducing sound field near the side of the speaker array 28 than the predetermined sound field boundary position and which supplies a near sound reproducing filter coefficients recorded in a filter coefficient selecting section 53.
[0066]
　Filter coefficient selection unit 53 based on the sound field near the boundary sound reproducing filter coefficient selection information supplied from the control unit 51, among the plurality of neighboring sound reproducing filter coefficient recorded in the vicinity of sound reproduction filter coefficient recording unit 52 select one neighboring sound reproducing filter coefficients from and supplies to the filter unit 26.
[0067]
　Gain adjusting unit 25, based on the sound field near the boundary sound gain value supplied from the control unit 51 performs gain adjustment for the supplied sound signal, and supplies the sound source signal obtained in the filter unit 26. Sound source signal to be supplied to the gain adjusting unit 25, an acoustic signal in the time domain for reproducing the neighborhood sound.
[0068]
　Here, the source signal supplied to the gain adjusting unit 22 includes a sound source signal to be supplied to the gain adjusting unit 25 will be described an example which is a signal for reproducing sound having different contents, their sound source signal may be the same.
[0069]
　Filter unit 26, to the excitation signal supplied from the gain adjustment unit 25 generates a near sound reproducing signals by performing a filtering process using the near sound reproducing filter coefficients supplied from the filter coefficient selecting unit 53, It is supplied to the adder 27. In the filter unit 26, as filtering, convolution processing is performed convolving the sound source signal and the near sound reproducing filter coefficients.
[0070]
　Addition unit 27, and far sound reproduction signal supplied from the filter unit 23, adds the proximity sound reproduction signal supplied from the filter unit 26, the speaker drive signal for reproducing near sound and far sound simultaneously generated, supplied to the speaker array 28. In other words, a far sound reproduction signal and near sound reproducing signal in the addition section 27 are synthesized by speaker driving signal is generated.
[0071]
　Near the speaker array 28, for example, linear loudspeaker array, the planar speaker array, cyclic speaker array, such as a spherical speaker array, a loudspeaker array obtained by arranging a plurality of speakers, based on speaker drive signal supplied from the adder 27 to play the sound and distant sound.
[0072]

　Here, the coordinate system used in the description of the following description with reference to FIG.
[0073]
　That is, in the description of the following, the central position of the speaker array 28 is the origin O of the three-dimensional orthogonal coordinate system.
[0074]
　Furthermore, the three axes of the three-dimensional orthogonal coordinate system passes through the origin O, x-axis orthogonal to each other, it is a y-axis, and z-axis. Here, the direction of the x-axis, i.e. the x-direction is a direction lined with the speaker that constitute the speaker array 28. The direction of the y-axis, i.e. the y direction is the x direction and the perpendicular direction, and waves are a direction parallel to the direction that is output from the speaker array 28, these x and y directions perpendicular direction z axis, i.e. it is the z-direction. In particular, the direction output sound waves from the speaker array 28 is the positive direction of the y-direction.
[0075]
　Hereinafter, the position in space, which means an also mark the vector indicating the spatial position x-coordinate, using the y and z coordinates, (x, y, z) and. In the following, the speaker array 28 is continuously described as being linear loudspeaker array.
[0076]
　Next, each part of the perspective Betsuoto field forming apparatus 11 shown in FIG. 3 will be described in more detail.
[0077]
(Sound field boundary control unit)
　will be described first sound field boundary control unit 41 and the sound field boundary control unit 51.
[0078]
　In the sound field boundary control unit 41 and the sound field boundary control unit 51, the same processing is performed sound field boundary position is determined.
[0079]
　That is, the listener position information is that supplied as e.g. control information. Listener position information indicating the position of the listener in the space, image recognition and for the image captured by the camera, the listener detected using a sensor, can be obtained from an input position information by the user or the like.
[0080]
　In such a case, for example, the position of the listener indicated by the listener position information as the control information to be included in the listening area of ​​the distant sound or near sound, the sound field boundary position is determined.
[0081]
　More specifically, for example, there are a plurality of listeners in the space, if fewer listener near the speaker array 28, listening area enough to contain the listener who is in the vicinity of the speaker array 28 is in the vicinity of sound sound field boundary position is determined to be region.
[0082]
　In contrast, for example, an increasing number of listeners who are near the speaker array 28, which until when all the listener is no longer fit in the listening area near sound, distant sound field boundary position from the speaker array 28 by the y-direction is moved to a position being as listening area near sound is wider.
[0083]
　During playback of the thus near sound and distant sound, i.e. may be dynamically sound field boundary position during reproduction of the content is changed.
[0084]
　Further, for example, when the boundary position information as the control information is supplied, the position indicated by the boundary position information is a sound field boundary position.
[0085]
　When the sound field boundary position is determined, distant sound gain value in accordance with the determination result, near sound gain value, far sound reproduction filter coefficient selection information, and near sound reproducing filter coefficient selection information obtained.
[0086]
　For example actually sound field boundary position in forming the sound field is far sound gain value and near sound gain value, the position of the control point for forming a far sound reproduction sound field, when forming a near sound reproducing sound field determined by such as evanescent wave attenuation rate.
[0087]
　Conversely, far sound gain value and near sound gain value for the determined arbitrary position, the position of the control point distant sound reproduction sound field, by appropriately defining it and evanescent wave attenuation factor, the decision position such that a sound field boundary position, it is possible to form a far sound reproduction sound field and near sound reproducing sound field. In other words, far sound gain value and near sound gain value, the position of the control point distant sound reproduction sound field, by adjusting the evanescent wave attenuation factor may be a sound field boundary position an arbitrary position.
[0088]
　Specifically, for example, as far sound and near sound, respectively when reproducing the sound of the sound of the contents A and B, by adjusting the gain of the sound source signal of the sound of their contents, changes a sound field boundary position it can be. That is, it is possible to control the sound field boundary position.
[0089]
　For example, when the position of the speaker array 28 and the position of y = 0 as shown in FIG. 5, the content B to the y-direction, i.e. the sound pressure in the vicinity of sound is changed as shown by the straight line L21, the content A, that is the sound pressure of the distant sound and has been found to vary as indicated by a curve L22. The vertical axis in FIG. 5 shows the sound pressure and the horizontal axis represents the position in the y-direction.
[0090]
　Thus the sound pressure of the content A is changed as shown by the curve L22 (attenuation), when the sound pressure of the contents B is changed (attenuated) as shown in the straight line L21, the intersection of the curve L22 and the line L21, i.e. position shown in the arrow W11 becomes sound field boundary position.
[0091]
　From this state, by increasing the gain of the content A, that is, increasing the distant sound gain value, for example, the sound pressure of the content A, that is distant sound becomes changed as indicated by the curve L23 with respect to the y-direction .
[0092]
　In this example, the gain adjustment of the content A, is larger sound pressure of the contents A at each position in the y-direction, as a result, the sound field boundary position is moved closer to the speaker array 28. That is, the sound field boundary position in accordance with an increase in the sound pressure of the content A is approaching the speaker array 28. In this case, intersections of curves L23 and the line L21, i.e., the position indicated by arrow W21 becomes sound field boundary position.
[0093]
　Similarly, even sound field boundary position changes by adjusting the gain of the content B. In this case, increasing the gain of the content B, that an increase in the vicinity of sound gain value, the sound field boundary position will be away from the speaker array 28.
[0094]
　For this reason, with respect to the determined sound field boundary position, suitably by determining the distant sound gain value and near sound gain value, when the formed near sound reproducing sound field and far sound reproduced sound field at the same time sound field border position can be made to be determined sound field boundary position.
[0095]
　In the sound field boundary control unit 41 and the sound field boundary control unit 51, in the case of using a prepared distant sound reproducing filter coefficients and near sound reproducing filter coefficients, the sound pressure of the distant sound or near sound each position in the y-direction how much and whether made in it is known in advance. In other words, the straight line L21 and L22 curve has become known.
[0096]
　Therefore, the sound field boundary control unit 41 and the sound field boundary control unit 51, to the determined sound field boundary position, distant sound such that sound field boundary position at the time of the sound field boundary position actual sound field it is possible to obtain the gain value and near sound gain value.
[0097]
　Incidentally, it may also be one only by the gain adjustment of the distant sound gain value and the neighboring sound gain value is performed, may be a combination of them both is the gain adjustment is performed. For example, when a substantially gain adjusted by only the distant sound gain value is performed, the neighborhood sound gain value is set to 1.
[0098]
　When performing control of the sound field boundary position only in the far sound gain value and near sound gain value, far sound reproduction filter coefficients and near sound reproducing filter coefficients each one (one kind) need only prepare.
[0099]
　Further, even sound field boundary position by changing the position of the control point distant sound reproducing filter coefficients for forming a far sound reproduction sound field is changed.
[0100]
　For example, in the sound field using a speaker array, a direction lined with the speaker constituting the speaker array, i.e. where there are control lines and a control point group called parallel reference lines and the x-direction. Then, it is possible to match the ideal sound field only formed sound field on the control point.
[0101]
　The distant sound reproducing filter coefficient recording unit 42, each of the plurality of control points, i.e. the far sound reproducing filter coefficient for each position in the y direction of the control points are recorded in advance, a predetermined one control point positions of them distant sound reproducing filter coefficients are supplied is selected by the filter unit 23.
[0102]
　As far sound and near sound, when reproducing the sound of the sound and the content B of each content A, the position of the control point distant sound reproducing filter coefficients used for generation of the far sound reproduction signal for reproducing the sound of content A When changes, for example, the sound field boundary positions as shown in FIG. 6 changes. The vertical axis in FIG. 6 shows the sound pressure and the horizontal axis represents the position in the y-direction.
[0103]
　In the example of FIG. 6, the position of the speaker array 28 is the position of y = 0, the straight line L31 shows the sound pressure of the content B, that is near the sound at each position in the y-direction. The curve L32 indicates the sound pressure of the content A, that is distant sound at each position in the y-direction. That is, the straight line L31 and the curve L32 shows how the attenuation of sound pressure with respect to the y-direction of the content B and content A.
[0104]
　In the case of using a distant sound reproduction filter coefficients and near sound reproducing filter coefficients as described above, or the sound pressure of the distant sound or near sound becomes degree at each position in the y-direction is known.
[0105]
　Thus the sound pressure of the content A is changed as shown by the curve L32, the sound pressure of the contents B is when the changes as shown in the straight line L31, the intersection of the curve L32 and the line L31, i.e., the position indicated by the arrow W21 the sound field boundary position.
[0106]
　For example, where the position of the control point distant sound reproducing filter coefficients sound pressure shown by the curve L32 is obtained is assumed to be y = y1.
[0107]
　In contrast, the position of the control point instead of the distant sound reproducing filter coefficients is y1, the position of control points than y1, the distant sound reproduction filter coefficient is y = y2 more distant from the speaker array 28 It used to generated the distant sound reproduction signal for reproducing the sound of content a to.
[0108]
　In this case, the sound pressure of the content A is changed as indicated by a curve L33 with respect to the y-direction, the sound field boundary position is a position indicated by the arrow W22.
[0109]
　Thus, if the farther the position of the control point from the speaker array 28 in the y-direction, the sound field boundary position is found to approach the speaker array 28. Conversely, when brought closer to the position of the control point of the speaker array 28 in the y-direction, the sound field boundary position is away from the speaker array 28.
[0110]
　For this reason, with respect to the determined sound field boundary position, the control points of a suitably distant sound reproduced sound field, i.e. by determining the control points of the far sound reproduction filter coefficients, near sound reproducing sound field and far sound sound field boundary position when formed reproduced sound field at the same time it can be made to be determined sound field boundary position.
[0111]
　In the sound field boundary control unit 41 and the sound field boundary control unit 51, in the case of using a prepared distant sound reproducing filter coefficients and near sound reproducing filter coefficients, the sound pressure of the distant sound or near sound each position in the y-direction how much and whether made in it is known in advance.
[0112]
　Therefore, the sound field boundary control unit 41 and the sound field boundary control unit 51, to the determined sound field boundary position, distant sound such that sound field boundary position at the time of the sound field boundary position actual sound field it is possible to obtain the position of the control point of the reconstruction filter coefficients.
[0113]
　Furthermore, for example, the sound pressure attenuation rate near sound reproducing filter coefficients for forming a near sound reproducing sound field, i.e., the sound field boundary position by changing the attenuation factor of the evanescent wave is changed.
[0114]
　In the vicinity of sound reproduction filter coefficient recording unit 52, near sound reproducing filter coefficient for each combination of the control points and the α constant that indicates the sound pressure attenuation rate in the y direction is recorded in advance, one neighboring sound of them reconstruction filter coefficients are supplied is selected by the filter unit 26.
[0115]
　As example far sound and neighboring tones, respectively when reproducing the sound of the sound of the contents A and B, the constant in the vicinity of sound reproduction filter coefficients used for generating the near sound reproducing signal for reproducing the sound of content B alpha, i.e. When the sound pressure attenuation rate is changed, for example, the sound field boundary positions as shown in FIG. 7 changes. The vertical axis in FIG. 7 shows the sound pressure and the horizontal axis represents the position in the y-direction.
[0116]
　In the example of FIG. 7, the position of the speaker array 28 is the position of y = 0, the straight line L41 shows the sound pressure of the content B, that is near the sound at each position in the y-direction. The curve L42 indicates the sound pressure of the content A, that is distant sound at each position in the y-direction. That is, the straight line L41 and the curve L42 shows how the attenuation of sound pressure with respect to the y-direction of the content B and content A.
[0117]
　Thus the sound pressure of the content A is changed as shown by the curve L42, the sound pressure of the contents B is when the changes as shown in the straight line L41, the intersection of the curve L42 and the line L41, i.e., the position indicated by the arrow W31 the sound field boundary position.
[0118]
　For example, where the value of the constant α in the vicinity of sound reproduction filter coefficients sound pressure shown by the straight line L41 is obtained is assumed to be [alpha] 1.
[0119]
　In contrast, in place of the near sound reproducing filter coefficient is a constant alpha = [alpha] 1, greater than the sound pressure attenuation rate than when a constant alpha = [alpha] 1, with the near sound reproducing filter coefficient is a constant alpha = [alpha] 2 and generating the neighborhood sound reproduction signal for reproducing the sound of content B.
[0120]
　In this case, the sound pressure of the contents B are changed as shown in the straight line L43 to the y-direction, the sound field boundary position is a position indicated by the arrow W32.
[0121]
　Thus, the use of large near sound reproducing filter coefficients of more sound pressure attenuation rate, the sound field boundary position is found to approach the speaker array 28. Conversely, the use of smaller near sound reproducing filter coefficients a more sound pressure attenuation rate, the sound field boundary position is away from the speaker array 28.
[0122]
　For this reason, with respect to the determined sound field boundary position, the sound pressure attenuation rate of the appropriately near sound reproducing filter coefficients, namely by determining the constants alpha, near sound reproducing sound field and far sound reproduction sound field sound field boundary position when forming simultaneously, can be made to be determined sound field boundary position.
[0123]
　In the sound field boundary control unit 51 and the sound field boundary control unit 41, in the case of using a prepared distant sound reproducing filter coefficients and near sound reproducing filter coefficients, the sound pressure of the distant sound or near sound each position in the y-direction how much and whether made in it is known in advance.
[0124]
　Therefore, the sound field boundary control unit 51 and the sound field boundary control unit 41, to the determined sound field boundary position, the sound field boundary position actual sound field near sound such that sound field boundary position at the time of forming it is possible to determine the constants α reconstruction filter coefficients.
[0125]
　Incidentally, the vicinity sound reproducing filter coefficients have been prepared for each combination of constant α and the control point indicating a sound pressure attenuation rate, even sound field boundary position by changing the control point of the near sound reproducing filter coefficient is changed . Therefore, it is also possible to appropriate control points in response to the sound field boundary position also near sound reproducing filter coefficients are determined.
[0126]
　As described above, the distant sound gain value and near sound gain value, the control point distant sound reproducing filter coefficients, the sound field boundary position by a control point and constant near sound reproducing filter coefficient α is changed.
[0127]
　Therefore, the sound field boundary control unit 41 and the sound field boundary control unit 51, far sound gain value for the determined sound field boundary position, near sound gain value, the control point distant sound reproducing filter coefficients, and near sound reproducing to determine the appropriate combination of control points and constant α of the filter coefficients.
[0128]
　In this case, the far sound gain value, near sound gain value, the control point distant sound reproducing filter coefficients, the control points of the neighboring sound reproducing filter coefficients, and some is dynamically determined from among the constant α in the vicinity of sound reproduction filter coefficients it is, may also be determined in advance and the others.
[0129]
　Particularly, upon determination of the parameters such as the distant sound gain value, there is a case for example at a predetermined position in the y-direction should be considered like wants to secure the desired sound pressure. Moreover, listening region distant sound or near sound in sound field is required is the side farther from the speaker array 28 than the control point.
[0130]
　Therefore, for example, be changed only the control points of a distant sound reproducing filter coefficient according to the sound field boundary position, it may not be able to or forming a listening area in position or secure the desired sound pressure is there. However, not only the control points of the distant sound reproducing filter coefficients, such as changing a combination also distant sound gain value and near sound gain value, if to dynamically determine a plurality of parameters, ensure the desired sound pressure or, it is possible to or forming a listening area in position.
[0131]
　In this way, the value of each parameter is determined for the sound field boundary position, for example, the sound field boundary control unit 41, information indicating the position of control points of the determined distant sound reproducing filter coefficients, distant sound and it supplies the filter coefficient selection unit 43 as the reproduction filter coefficient selection information. Further, for example, the sound field boundary control unit 51 supplies the position information indicating the constants α of control points near sound reproducing filter coefficients, the filter coefficient selecting section 53 as a near sound reproducing filter coefficient selection information determined.
[0132]
(Distant sound reproducing filter coefficient recording unit)
　distant sound reproducing filter coefficient recording unit 42 records the distant sound reproduction filter coefficient for each position of the plurality of control points.
[0133]
　For example distant sound reproducing filter coefficients are as previously obtained by the SDM (Spectral Division Method) method.
[0134]
　It is to be noted that the SDM method, for example, "Jens Ahrens and Sascha Spors," Sound Field Reproduction Using Planar and Linear Arrays of Loudspeakers ", in IEEE TRANSACTIONS ON AUDIO, SPEECH, AND LANGUAGE PROCESSING, VOL. 18, NO. 8, NOVEMBER 2010 . "it is described in detail in such.
[0135]
　For example, the sound field P (v, n in the three-dimensional free space tf ) is expressed as shown in the following equation (1).
[0136]
[Number 1]

[0137]
　Incidentally, n in formula (1) tf represents time frequency index, v is v = a vector indicating the position in space (x, y, z). Further, v in the equation (1) 0 is a vector indicating a predetermined position on the x-axis v 0 = (x 0 , 0,0) is. In the following, also referred to as position location v indicated by vector v, the vector v 0 position v a position indicated by 0 and also referred to.
[0138]
　Further, the formula (1) in D (v 0 , n tf ) shows the driving signals of the secondary source, G (v, v 0 , n tf ), the position v and the position v 0 is transmitted between the it is a function. The drive signal D of the secondary source (v 0 , n tf ) corresponds to the far sound reproduction signal.
[0139]
　The calculation of such equation (1), in the spatial domain drive signal D (v 0 , n tf ) and the transfer function G (v, v 0 , n tf has a form of convolution of), the formula (1 sound field P (v shown), n tf when spatial Fourier transform) on the x-axis direction, as shown in the following equation (2).
[0140]
[Number 2]

[0141]
　In the equation (2), n sf represents the spatial frequency index.
[0142]
　Thus sound field P (v, n tf ) when the spatial Fourier transform, sound field P of the spatial frequency domain as shown in equation (2) F (n sf , y, z, n tf ) is the spatial frequency domain of the drive signal D F (n sf , n tf ) and the transfer function G F (n sf , y, z, n tf ) represented by the product of the. Therefore, the spatial frequency representation of the drive signal of the secondary sound source is as shown in equation (3).
[0143]
[Number 3]

[0144]
　In the case of using the straight line of the secondary source, the straight line and the parallel control point, i.e. it is possible monkey actually match the ideal sound field sound field formed only on the reference line. Therefore, the position in the y direction of the control point y = y ref and, also when the z = 0 for considering the sound field on the horizontal plane, the equation (3) becomes as shown in equation (4).
[0145]
[Formula 4]

[0146]
　The drive signal D of the secondary sound source represented by the formula (4) F (n sf , n tf ) is, y = y ref as control points the position of, for forming an ideal sound field at the control point which is a drive signal.
[0147]
　Further, for example, the desired sound field to P F (n sf , y ref , 0, n tf as), the following equation point as shown in (5) Instrument Model P ps (n sf , y ref , 0, n tf a) it can be used.
[0148]
[Formula 5]

[0149]
　In the equation (5), S (n tf ) shows the sound source signal of the sound to be reproduced, j denotes an imaginary unit, k x represents the wave number of the x-axis direction. Further, x ps and y ps shows the x and y coordinates indicate the position of each point source, omega denotes an angular frequency, c is it shows the speed of sound. Furthermore, H 0 (2) shows a second kind Hankel function, K 0 denotes the Bessel function. Since the distant sound reproducing filter coefficients does not depend on the sound source, where S (n tf are) = 1.
[0150]
　Further, the transfer function G F (n sf , y ref , 0, n tf ) can be expressed as shown in the following equation (6).
[0151]
[Number 6]

[0152]
　Or of formula (4), Equation (5), and equation (6) is used, the drive signal D F (n sf , n tf ), i.e. the spatial frequency spectrum of the far sound reproduction signal D F (n sf , n Tf ) is required.
[0153]
　Then, the spatial frequency spectrum D F (n sf , n tf ) and that the spatial frequency synthesized using DFT (Discrete Fourier Transform), the time-frequency spectrum D (l, n tf ) is determined. That is, by calculating the following equation (7), the time-frequency spectrum D (l, n tf ) is calculated.
[0154]
[Number 7]

[0155]
　In the equation (7), l identifies the speaker constituting the speaker array 28 shows a speaker index of the position in the x direction of the speaker, M ds denotes the number of samples of DFT.
[0156]
　Moreover, the time-frequency spectrum D (l, n tf ) against, IDFT (Inverse Discrete Fourier Transform) is performed time-frequency synthesis using a speaker drive signal d (l of the speakers of the speaker array 28 which is a time signal , N D ) is obtained. Specifically, by performing the calculation of equation (8), the speaker drive signal d (l, n d ) is calculated. These speaker driving signal d of each speaker (l, n d ) is distant sound reproduction signal.
[0157]
[Number 8]

[0158]
　In Expression (8), n d denotes the time index, M dt denotes the number of samples of IDFT.
[0159]
　Thus speaker drive signal obtained by d (l, n d ) represents the filter coefficient itself does not depend on the sound source. Therefore, the speaker drive signal d (l, n d ) time index n of d and is replaced with the time index m, the position of the point source (x ps , y ps ) position y = y of and control point ref about the obtained distant sound reproducing filter coefficient h f (l, m) are.
[0160]
　Here, the one control point, distant sound reproducing filter coefficient h for each speaker identified by the speaker index l of the speaker array 28 f (l, m) is obtained.
[0161]
　The distant sound reproducing filter coefficient recording unit 42, distant sound reproducing filter coefficients of each of a plurality of control points h f (l, m) is recorded in advance.
[0162]
　Therefore, the filter coefficient selecting unit 43, distant sound reproducing filter coefficients for a plurality of control points h f (l, m) of the indicated by distant sound reproducing filter coefficient selection information supplied from the sound field boundary control unit 41 distant sound reproducing filter coefficients h of the same control point and the control point f supplied to the filter unit 23 reads (l, m) from the distant sound reproducing filter coefficient recording unit 42.
[0163]
　Although the control point group becomes planar in the case of using a planar secondary source when obtaining the distant sound reproduction filter coefficients, as in the case of using the straight line of the secondary source even if such a it can be obtained a far sound reproduction filter coefficient Te.
[0164]
(Near sound reproducing filter coefficient recording unit)
　near sound reproducing filter coefficient recording unit 52 records the near sound reproducing filter coefficients for each combination of the position of the plurality of control points, a plurality of constant alpha. These near sound reproducing filter coefficient is a filter coefficient of an acoustic filter for the evanescent wave decays in the y direction generated by the speaker array 28.
[0165]
　Such near sound reproducing filter coefficients, for example, obtained as follows.
[0166]
　For example in a three-dimensional free space, the sound field p (v, t) of time t at an arbitrary position v satisfies the wave equation in the following equation (9).
[0167]
[Number 9]

[0168]
　Note that c in formula (9) shows the speed of sound, ∇ 2 is as shown in the following equation (10).
[0169]
[Formula 10]

[0170]
　Furthermore, assuming that the shown time inverse Fourier transform T (t) into the following equation (11), time Fourier transform F (·) is as shown in the following equation (12).
[0171]
[Number 11]

[0172]
[Number 12]

[0173]
　In the equation (11) and Equation (12), j denotes an imaginary unit, omega represents the angular frequency.
[0174]
　Here, with respect to formula (9) described above, by dividing the derivative of performing separation of variables as shown in the following equation (13) space of the derivative and time, when further using Equation (12), the following formula Helmholtz equation shown in (14) is obtained.
[0175]
[Formula 13]

[0176]
[Number 14]

[0177]
　Incidentally, P in equation (14) (v, ω) indicates the sound field of the angular frequency omega at position v. Furthermore, the angular frequency omega pw is, x-direction, y-direction, and each wave number of the z-direction is k pw, x , k pw, y , and k pw, z when a, angular frequency omega pw , wavenumber k pw, x , wavenumber k pw, y , and wavenumber k pw, z represents a plane wave propagating in the direction represented by the general solution of the Helmholtz equation shown in equation (14), as shown in the following equation (15) to become.
[0178]
[Number 15]

[0179]
　In the equation (15) [delta] (omega-omega pw ) show a delta function.
[0180]
　Here, in the wave number region, the relationship is established in the following equation (16).
[0181]
[Number 16]

[0182]
　Wavenumber k of equation (16) y-direction pw, y is solved for, as shown in the following equation (17).
[0183]
[Formula 17]

[0184]
　Upper of formula (17), that the wave number k is shown in the upper pw, y wave represents the normal propagation wave, the wave number k is shown the lower part, i.e. the lower side of the equation (17) pw, y wave it represents the evanescent wave.
[0185]
　Therefore, the wave number k of the evanescent wave shown in the lower part of equation (17) pw, y sound showed in equation (15) field P (v, omega) is substituted into, as shown in the following equation (18).
[0186]
[Equation 18]

[0187]
　However, the wave number k pw, y Upon substituting the equation (15), the wave number k pw, y because the sign of the positive terms as a solution without a physical sense, the term sign is negative assignment It is.
[0188]
　Further, in the formula (18) (k pw, x 2 + k pw, z 2 - (omega / c) 2 ) 1/2 is a term that defines the magnitude of the attenuation of evanescent waves.
[0189]
　Thus, for example, without depending on angular frequency omega, if you want to the size of the constant attenuation, using a constant α which represents the magnitude of the attenuation, the wave number k so as to satisfy the following equation (19) pw, x and wavenumber K Pw, Z may be set. In this case, the larger the constant α as seen from equation (18), evanescent wave attenuation rate in the y-direction increases. Such constant represented by formula (19) alpha is a constant that indicates the sound pressure attenuation rate in the y direction as described above.
[0190]
[Number 19]

[0191]
　Now consider the determination of the near sound reproducing filter coefficients for obtaining a near sound reproducing signal for generating evanescent waves that are represented by the formula (18).
[0192]
　If equation (18) for spatially Fourier transform for x, is expressed as shown in equation (20).
[0193]
[Number 20]

[0194]
　Further, the spatial frequency spectrum G of the transfer function '(k x , y, z, omega) is expressed as shown in the following equation (21).
[0195]
[Number 21]

[0196]
　Incidentally, H in the formula (21) 0 (2) shows a second kind Hankel function, K 0 denotes the Bessel function.
[0197]
　Furthermore, from SDM method using equations (20) Equation (21), the spatial frequency spectrum D '(k near sound reproducing signal x , omega) is as shown in the following equation (22).
[0198]
[Equation 22]

[0199]
　In the formula (22), y ref represents the position of the control point as a reference in the y-direction.
[0200]
　The thus obtained formula (22), the wave number k x by inverse spatial Fourier transform on the time-frequency spectrum D (x, omega) in the vicinity of sound reproduction signal shown in equation (23) is obtained.
[0201]
[Number 23]

[0202]
　Furthermore, this manner to inverse temporal Fourier transform and the resulting time-frequency spectrum D (x, ω), the time waveform d in the vicinity of sound reproduction signal as shown in the following equation (24) (x, t), i.e. the time signal at a speaker drive signal d (x, t) is obtained.
[0203]
[Number 24]

[0204]
　At this time, to identify the speaker constituting the speaker array 28, when the index of the position in the x direction of the speaker and l, as shown in the following equation (25), from equation (24) of the index l of the speaker near sound reproducing filter coefficient h n (l, m) is obtained.
[0205]
[Number 25]

[0206]
　In the equation (25), m indicates a time index. The near sound reproducing filter coefficient h n (l, m) is obtained by replacing the speaker drive signal d (x, t) shown in Formula (24) with x in is replaced with the index l, t to time index m It is.
[0207]
　In the vicinity of sound reproduction filter coefficient recording unit 52, positions of the plurality of control points y ref and near sound reproducing filter coefficient for each combination of the plurality of constant h alpha n (l, m) is recorded in advance.
[0208]
　Therefore, the filter coefficient selecting unit 53, their neighboring sound reproducing filter coefficient h n (l, m) of the control point indicated by the near sound reproducing filter coefficient selection information supplied from the sound field boundary control unit 51 and constant near sound reproducing filter coefficients of the same control point and constant alpha and h alpha n (l, m) is supplied to the filter unit 26 reads from the vicinity sound reproducing filter coefficient recording unit 52.
[0209]
　Further, in the above, obtains the evanescent wave in the wave number region, near sound reproducing filter coefficient h n (l, m) has been described a method of calculating a neighborhood sound reproduction filter coefficients to generate an evanescent wave in any other way h n (l, m) may be obtained.
[0210]
(Filter unit)
　For example, the excitation signal supplied from the gain adjustment unit 22 to the filter unit 23, without further distinguishing the sound signal supplied from the gain adjustment unit 25 to the filter unit 26 and the sound source signal x (n) and referred to. Incidentally, n in the sound source signal x (n) represents the time index.
[0211]
　Also, the far sound reproduction filter coefficient h f (l, m) and near sound reproducing filter coefficient h n (l, m) and when it is not necessary to distinguish, and the filter coefficients h (l, m) and also referred to.
[0212]
　In the filter unit 23 and filter unit 26, the supplied excitation signal x (n), the filter coefficients h (l, m) convolving a speaker drive signal s (l, n) processing of obtaining the is performed. That is, in the filter unit 23 and filter unit 26, is carried out the calculation of equation (26) for each speaker constituting the speaker array 28, the speaker drive signal of each speaker is identified by the speaker index l s (l, n ) is calculated.
[0213]
[Number 26]

[0214]
　In the equation (26), N denotes the filter length.
[0215]
　Such loudspeaker drive signal s (l, n) of each speaker obtained by the filter unit 23 by the calculation of equation (26) is distant sound reproduction signal. Further, a filter of each speaker obtained in 26 speaker drive signal s (l, n) is near sound reproducing signal by the calculation of equation (26).
[0216]

　Subsequently, the operation of the perspective Betsuoto field forming apparatus 11. That is, below with reference to the flowchart of FIG. 8, will be described perspective Betsuoto field generation processing performed by the perspective Betsuoto field forming apparatus 11.
[0217]
　In step S11, the sound field boundary control unit 41 and the sound field boundary control unit 51 determines a sound field boundary position based on the supplied control information.
[0218]
　For example the sound field boundary control unit 41 and the sound field boundary control unit 51 based on the position of the listener indicated by the supplied listener position information as control information, and a listening area of ​​the listening area and far sound near sound determined, the position between those listening area and sound field boundary position. Further, for example, the sound field boundary control unit 41 and the sound field boundary control unit 51, a position to directly sound field boundary positions indicated by the supplied boundary position information as control information.
[0219]
　In step S12, the sound field boundary control unit 41 and the sound field boundary control unit 51, based on the sound field boundary position determined by the processing in step S11, to determine the parameters of such distant sound gain value.
[0220]
　That is, the sound field boundary control unit 41 and the sound field boundary control unit 51, as described with reference to FIGS example, depending on the sound field boundary position, distant sound gain value as a parameter, near sound gain value, the position of the control point distant sound reproducing filter coefficients, to determine the respective values ​​of the constants α position, and near sound reproducing filter coefficients of the control points near sound reproducing filter coefficients.
[0221]
　Incidentally, the value some predetermined one of the parameters may be determined based on the value the sound field boundary positions of the remaining parameters. Further, after determining the sound field boundary position, instead of determining the value of each parameter in response to the sound field boundary position, so that the sound field boundary position and the value of each parameter is determined at the same time while being adjusted to each other it may be. That is, the processing of steps S11 and S12 may be performed simultaneously.
[0222]
　When the parameters are determined, along with the sound field boundary control unit 41 supplies the distant sound gain value as the determined parameters to the gain adjusting unit 22, the control point distant sound reproducing filter coefficients as the determined parameters the information indicating the position, and supplies the filter coefficient selecting part 43 as far sound reproduction filter coefficient selection information.
[0223]
　Also, the sound field boundary control unit 51 shown supplies neighboring sound gain value as the determined parameters to the gain adjusting unit 25, the position and constant α of control points near sound reproducing filter coefficients as the determined parameters information is supplied to the filter coefficient selector 53 as the near sound reproducing filter coefficient selection information.
[0224]
　In step S13, the filter coefficient selecting unit 43 and the filter coefficient selector 53 selects the filter coefficients.
[0225]
　Specifically, the filter coefficient selecting unit 43, from among the distant sound reproducing filter coefficients for a plurality of control points, the control point indicated by the distant sound reproducing filter coefficient selection information supplied from the sound field boundary control unit 41 to select the distant sound reproduction filter coefficient. In other words, far sound reproduction filter coefficient corresponding to the position of the control point indicated by the distant sound reproducing filter coefficient selection information is selected.
[0226]
　Then, the filter coefficient selecting unit 43 supplies the filter unit 23 reads out the selected distant sound reproducing filter coefficients from the far sound reproducing filter coefficient recording unit 42.
[0227]
　The same manner, the filter coefficient selecting section 53, shown from among the neighboring sound reproducing filter coefficients for each combination of a plurality of control points and constant alpha, the sound field near sound reproducing filter coefficient selection information supplied from the boundary control unit 51 selecting a neighborhood sound reproduction filter coefficient position and a constant α of the control points. That is, near sound reproducing filter coefficient corresponding to the position and the constant α of the control point indicated by the near sound reproducing filter coefficient selection information is selected.
[0228]
　Then, the filter coefficient selecting unit 53 supplies the filter unit 26 reads out the selected near sound reproducing filter coefficients from the vicinity sound reproducing filter coefficient recording unit 52.
[0229]
　In step S14, the gain adjustment unit 22 and the gain adjusting unit 25 adjusts the gain of the supplied sound signal.
[0230]
　Filter or gain adjustment unit 22, the supplied sound signals from the sound field boundary control unit 41 by multiplying the supplied far sound gain value adjusts the gain, the resulting sound source signal supplied to the part 23.
[0231]
　The gain adjustment unit 25, the supplied source signal, adjusts the gain by multiplying the supplied near sound gain value from the sound field boundary control unit 51, the filter and the resulting sound source signal supplied to the part 26.
[0232]
　In step S15, the filter unit 23 and filter unit 26 performs filter processing of the sound source signal.
[0233]
　That is, for example the filter unit 23 by performing the calculation of equation (26) above, convoluting the excitation signal supplied from the gain adjustment unit 22, and a distant sound reproduction filter coefficients supplied from the filter coefficient selector 43 in generating the distant sound reproduction signal, and supplies to the adder 27.
[0234]
　Further, for example, the filter unit 26 by performing the calculation of equation (26) above, convoluting the excitation signal supplied from the gain adjustment unit 25, and a near sound reproducing filter coefficients supplied from the filter coefficient selector 53 in generating a near sound reproducing signal, and supplies to the adder 27.
[0235]
　Here, it has been described. Distant sound reproduction signal and near sound reproducing signal used excitation signal gain adjustment is performed is generated. However, the gain adjustment is used excitation signal not performed is far sound reproduction signal and near sound reproducing signal is generated, as the gain adjustment is performed on their distant sound reproduction signal and near sound reproducing signal it may be.
[0236]
　In such a case, for example, the gain by the adjusting unit 22 gain adjustment for distant sound reproduction signal based on the distant sound gain value is performed, the gain adjustment lines for near sound reproducing signal based on the near sound gain value by the gain adjusting unit 25 divide.
[0237]
　In step S16, the adding unit 27, and far sound reproduction signal supplied from the filter unit 23, adds the proximity sound reproduction signal supplied from the filter unit 26 to generate a loudspeaker drive signal, supplied to the speaker array 28 to.
[0238]
　In step S17, the speaker array 28 simultaneously play the distant sound and near sound on the basis of the speaker drive signal supplied from the adder 27, perspective Betsuoto field generation process ends.
[0239]
　When far sound and near sound is reproduced at the same time in this way, and far sound reproduction sound field and near sound reproducing sound field in the different regions of the space is formed. That is, the listening region of the distant sound, and the listening area near sound is formed at different positions.
[0240]
　Perspective Betsuoto field forming apparatus 11 as described above, the sound field to determine the parameters of such distant sound gain value in accordance with a boundary position, distant sound performs gain adjustment and filtering in accordance with the determined parameters generating a speaker drive signal for reproducing the neighborhood sound and. In this way, it is possible to play different sounds at the far and near.
[0241]

　In addition, to produce a loudspeaker drive signal by adding the distant sound reproduction signal and near sound reproducing signal in the above, one of the speaker array 28 in an example it has been described to play a far sound and near sound may be reproduced by a different speaker array far sound and near sound, respectively.
[0242]
　In such a case, near-far Betsuoto field generating apparatus is arranged as shown for example in FIG. Note that portions corresponding to the case in FIG. 3 in FIG. 9 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
[0243]
　Perspective Betsuoto field forming apparatus 81 shown in FIG. 9, and far sound field processing unit 21, the gain adjusting unit 22, the filter unit 23, near the sound field processor 24, a gain adjustment section 25, the filter unit 26, the speaker array 28, and a speaker array 91.
[0244]
　The sound field boundary control unit 41 in the far sound field processor 21, distant sound reproducing filter coefficient recording unit 42, and a filter coefficient is selected portion 43 is provided, the sound field in the vicinity of the sound field processor 24 boundary control unit 51, near sound reproducing filter coefficient recording unit 52 and the filter coefficient selector 53 is provided.
[0245]
　The configuration of the perspective Betsuoto field generating device 81, adding section 27 is not provided, newly unlike the configuration perspective Betsuoto field forming apparatus 11 of FIG. 3 in that the speaker array 91 are provided, other in terms of it has the same structure as the perspective Betsuoto field forming apparatus 11.
[0246]
　In perspective Betsuoto field forming apparatus 81, the far sound reproduction signal obtained by the filter section 23 is supplied to the speaker array 28, distant sound is reproduced based on distant sound reproduction signal in the speaker array 28. Also, near sound reproducing signal obtained by the filter unit 26 is supplied to the speaker array 91.
[0247]
　Speaker array 91, for example, linear loudspeaker array, the planar speaker array, cyclic speaker array, such as a spherical speaker array, a loudspeaker array obtained by arranging a plurality of speakers, based on the near sound reproducing signal supplied from the filter unit 26 Play the vicinity of sound.
[0248]
　Here, the speaker array 28 and the speaker array 91, may be disposed at the same position in the y-direction, it may be disposed in the y-direction at different positions.
[0249]
　For example, when the arrangement position of each of the y direction of the speaker array 28 and the speaker array 91 are different, the near sound reproducing sound field is not limited to the evanescent waves, to be formed by the propagating wave, such as a plane wave and a spherical wave It can also be.
[0250]
　Speaker This means that reproduces example and how the attenuation in the y direction of the sound pressure of the distant sound, be similar is how the attenuation in the y direction of the sound pressure in the vicinity of sound, and their distant sound and neighboring sound different y-position of the array, the attenuation curve of the sound pressure of these sounds, i.e. the curve corresponding to the curve L32 shown in FIG. 6, for example because having an intersection.
[0251]
　Therefore, the near sound reproducing filter coefficients, for example produced in the same manner as in the distance sound reproducing filter coefficients, it is also possible to filter coefficients for forming a near sound reproducing sound field due plane wave and a spherical wave.
[0252]

　Next, the operation of the perspective Betsuoto field forming apparatus 81 shown in FIG. That is, below with reference to the flowchart of FIG. 10 will be described perspective Betsuoto field generation processing performed by the perspective Betsuoto field forming apparatus 81.
[0253]
　The processing in steps S41 to step S45 is the same as the processing in steps S11 to S15 in FIG. 8, a description thereof will be omitted. However, in step S45, the filter unit 23 supplies the distant sound reproduction signal obtained to the speaker array 28, and supplies the filter unit 26 is near sound reproducing signal obtained speaker array 91.
[0254]
　In step S46, the speaker array 28 reproduces the distant sound based on the distant sound reproduction signal supplied from the filter unit 23.
[0255]
　Further, in step S47, the speaker array 91 reproduces the vicinity of sound based on the proximity sound reproduction signal supplied from the filter unit 26.
[0256]
　Incidentally, more specifically, step S46 and step S47 are performed simultaneously. Thus, a far sound reproduction sound field and near sound reproducing sound field in the different regions of the space is formed. That is, the listening region of the distant sound, and the listening area near sound is formed at different positions.
[0257]
　When far sound and near sound is reproduced, perspective Betsuoto field generation process ends.
[0258]
　Perspective Betsuoto field forming apparatus 81 as described above, the sound field to determine the parameters of such distant sound gain value in accordance with a boundary position, distant sound performs gain adjustment and filtering in accordance with the determined parameters It generates a reproduction signal and a near sound reproducing signal. In this way, it is possible to play different sounds at the far and near.
[0259]
　In the above it has been described as playing far sound and near sound simultaneously, may be far sound and near sound is reproduced at different timings.
[0260]
　In such a case, the distant sound reproduction is performed at the timing when the reproduction is not performed, for example, near the sound. Moreover, far sound may be played back when the volume of the near sound is small. That is, for example, the filter unit 23, also a sound source signal for reproducing the vicinity of sound to be supplied, the filter unit 23, such as when the amplitude of the sound source signal to reproduce the neighborhood sound is substantially zero, near sound when the volume is small, i.e. near sound to detect the timing does not play. The filter unit 23 supplies the distant sound reproduction signal to the speaker array 28 at a timing near noise being reproduced, thereby reproducing the distant sound.
[0261]
　In this way, when the neighboring sound is not reproduced, that is to play the distant sound when no sound in the vicinity of sound, even at a small difference the position of the sound pressure of the sound pressure and far sound near sound , it is possible to prevent that intermingled the distant sound and the vicinity of sound would be heard by the human listener.
[0262]
　Also, when playing different sounds using two speaker array 28 and the speaker array 91, with their speaker array 28 and the speaker array 91 are arranged in z-direction, is disposed at a position of that is different heights, different the sound of the content may be reproduced.
[0263]
　In such a case, for example, to play the content of the deployed tall adults in the speaker array 28 to a higher position in the z direction, less children tall in the speaker array 91 disposed at a lower position in the z-direction it is also possible to reproduce the content of. In this example, it is possible to reproduce different content for each height even in the vicinity of the speaker array.
[0264]
　Furthermore, for example, when arranging the speaker array 28 and the speaker array 91 at different heights z-direction, a single speaker array, as described in the first embodiment, reproducing the listening area two different sounds it may be.
[0265]
　In such a case, play a far sound and near sound by the speaker array 28, also playing a far sound and near sound even speaker array 91, 4 position of the listening area to each other in the z-direction and the y direction are different Tsunooto it is possible to form the field. At that time, the sound field boundary position distant sound and neighboring tone played by the speaker array 28, as the sound field boundary position distant sound and neighboring tone played by the speaker array 91 is different positions y-direction it is also possible to. That is, it is possible to control the sound field boundary position independently.
[0266]
　Thus play a far sound and near sound on each of the two speaker array, the four different contents from each other can be reproduced without their sound mix.
[0267]
　In the case of forming a different sound field in the far and near, may be presented in combination also video. For example, by installing the like polarizing plates with the display device above the speaker array 28, and the listener in the listening area of ​​the distant sound by the display device, each different in the listener in the listening region near sound video (image) it can be presented.
[0268]
　Thus, for example, with respect to the listener in the listening area of ​​the distant sound, to present content comprising a video and far sound visible from the listening area, for the listener in the listening area near sound, its it can present content comprising a video and near sound visible from listening area. That can present the listener in the listening area of ​​the distant sound, relative to the listener in the listening area near sound, different content respectively from the video and audio.
[0269]
　Other, for example, when you want to play a sound as heard only in the vicinity of the speaker array, may be used far sound masking vicinity sounds. In other words, it is possible to use a far sound as sound masking neighboring sound.
[0270]
　In such a case, for example, distant sound is a like BGM of the same frequency band as the neighborhood sounds, their distant sound and near sound is simultaneously reproduced by perspective Betsuoto field generating device 11 and the perspective Betsuoto field forming apparatus 81 . By this way, it is possible to make hardly hear the vicinity sound in the listening area outside the vicinity of sound. That is, it is possible to reduce the leakage of the near sound to the listening area outside.
[0271]
　In the case of using the far sound as sound masking near sound, a sound of a frequency band including all frequency bands of at least near sound when used as far sound, it is possible to improve the masking effect.
[0272]

　The series of processes described above can be executed by hardware or can be executed by software. When executing the series of processing by software, a program constituting the software is installed into a computer. Here, the computer includes a computer incorporated in dedicated hardware, by installing various programs, which can execute various functions include, for example, such as a general-purpose computer.
[0273]
　Figure 11 is a block diagram showing a configuration example of hardware of a computer that executes the series of processes described above.
[0274]
　In the computer, CPU (Central Processing Unit) 501, ROM (Read Only Memory) 502, RAM (Random Access Memory) 503 are connected to each other via a bus 504.
[0275]
　The bus 504 is further output interface 505 is connected. Output interface 505, an input unit 506, output unit 507, recording unit 508, a communication unit 509, and a drive 510 are connected.
[0276]
　Input unit 506 includes a keyboard, a mouse, a microphone, made of an imaging device. The output unit 507 includes a display and a speaker array. Recording unit 508, a hard disk and a nonvolatile memory. Communication unit 509 including a network interface. Drive 510 drives a magnetic disk, an optical disk, a magneto-optical disk, or a removable recording medium 511 such as a semiconductor memory.
[0277]
　Series In the computer configured as described above, CPU 501 is, for example, a program recorded in the recording unit 508 via the input-output interface 505 and the bus 504 and executes the loaded into RAM 503, the above-mentioned processing of is performed.
[0278]
　Program computer (CPU 501) is executed, for example, can be provided by being recorded in a removable recording medium 511 as a package medium or the like. Further, the program may be provided via a local area network, the Internet, or digital satellite broadcasting, a wired or wireless transmission medium.
[0279]
　In the computer, by mounting the removable recording medium 511 into the drive 510, it can be through the input-output interface 505, installed in the recording unit 508. The program via a wired or wireless transmission medium and received by the communication unit 509, can be installed in the recording unit 508. Alternatively, the program may be in the ROM502 and the recording unit 508 installed in advance.
[0280]
　The program which the computer executes may be a program in which processes are performed in time series in the order described herein, at a necessary timing such as when the parallel or call was made processing may be a program to be carried out.
[0281]
　Further, embodiments of the present technology is not limited to the embodiments described above, but various modifications are possible without departing from the scope of the present disclosure.
[0282]
　For example, the present technology, sharing one function by a plurality of devices via a network, it is possible to adopt a configuration of cloud computing which processes jointly.
[0283]
　Further, each step described in the above flowcharts may be executed by one device, it can be performed by allocating a plurality of apparatuses.
[0284]
　Further, when a plurality of processes are included in one step, the plurality of processes included in the one step may be executed by one device, it can be performed by allocating a plurality of apparatuses.
[0285]
　The effects described herein are not intended to be limited to a merely illustrative, there may be other effects.
[0286]
　Additionally, the present technology may also be configured as follows.
[0287]
(1)
　by performing a filtering process using the distant sound reproduction filter coefficient for the first sound source signal, and far filter unit which generates a far sound reproduction signal for reproducing sound in the far listening area,
　the second of by performing filtering processing using the neighborhood sound reproduction filter coefficients for the sound source signal, and the neighboring filter unit for generating a near sound reproducing signal for reproducing sound in different neighborhood listening region and the far listening area
　the signal processing apparatus comprising.
(2)
　the near sound reproducing signal is a signal for generating the evanescent wave
　signal processing apparatus according to (1).
(3)
　the far listening area and further comprising a near sound field processing unit for determining the attenuation factor of the evanescent wave in accordance with a boundary position between the neighboring listening area,
　the neighboring filter unit, a plurality of the neighboring sound reproducing filter the filtering process is performed using the near sound reproducing filter coefficient corresponding to the attenuation factor determined within the coefficient
　signal processing apparatus according to (2).
(4)
　further comprising a near sound field processing unit for determining the position of the control point in response to the boundary position between the far listening area and the vicinity listening area,
　the neighboring filter unit, a plurality of the neighboring sound reproducing filter coefficients using said near sound reproducing filter coefficient corresponding to the position of the control points determined in out to filter
　(1) or the signal processing apparatus according to (2).
(5)
　further comprising a far sound field processing unit for determining the position of the control point in response to the boundary position between the far listening area and the vicinity listening area,
　the distal filter section, a plurality of the distant sound reproducing filter coefficients using the distant sound reproduction filter coefficient corresponding to the position of the control points determined in out to filter
　(1) through (4) the signal processing apparatus according to any one of.
(6)
　the distal sound reproduction signal is a signal for generating a propagating wave
　(1) to the signal processing apparatus according to any one of (5).
(7)
　and the far listening area and the far sound field processing unit for determining a gain in accordance with the boundary position between the vicinity of the listening area,
　based on the determined the gain of the first sound source signal or the distant sound reproduction signal gain adjustment and far gain adjustment unit which performs
　further comprises (1) to the signal processing apparatus according to any one of (6).
(8)
　and the far listening area and the near vicinity sound field processing unit for determining a gain in accordance with the boundary position between the listening area,
　based on the determined the gain of the second sound source signal or the near sound reproducing signal gain adjustment and the neighboring gain adjustment unit which performs
　further comprises (1) to the signal processing apparatus according to any one of (7).
(9)
　wherein the first sound signal and the second sound source signal is a signal for reproducing sound having different contents
　(1) to the signal processing apparatus according to any one of (8) .
(10)
　further comprising a speaker array for reproducing sound based on a signal obtained by combining the far sound reproduction signal and the near sound reproducing signal
　signal processing according to any one of (1) to (9) apparatus.
(11)
　wherein a first of the speaker array for reproducing sound based on distant sound reproduction signal,
　and a second speaker array for reproducing sound based on the proximity sound reproduction signal
　further comprises (1) to (9) the signal processing apparatus according to any one of.
(12)
　a sound based on the distant sound reproduction signal is reproduced at a timing different from that of the sound based on the proximity sound reproduction signal
　signal processing apparatus according to any one of (1) to (11).
(13)
　a sound based on the distant sound reproduction signal is the sound for masking sound based on the proximity sound reproduction signal
　(1) to the signal processing apparatus according to any one of (11).
(14)
　based on the listener's position in space, further comprising a sound field boundary control unit which determines the boundary position between the far listening area and the vicinity listening area
　in any one of (1) to (13) the signal processing apparatus according.
(15)
　by performing the filtering process using the distant sound reproduction filter coefficients for the first excitation signal to generate a distant sound reproduction signal for reproducing sound in the far listening area,
　to the second sound source signal by performing the filtering process using the near sound reproducing filter coefficients for, for generating a near sound reproducing signal for reproducing sound in different neighborhood listening region and the far listening area
　signal processing method comprising the steps.
(16)
　by performing the filtering process using the distant sound reproduction filter coefficients for the first excitation signal to generate a distant sound reproduction signal for reproducing sound in the far listening area,
　to the second sound source signal by performing the filtering process using the near sound reproducing filter coefficients for, for generating a near sound reproducing signal for reproducing sound in different neighborhood listening region and the far listening area
　to execute a process including the steps on a computer program.
DESCRIPTION OF SYMBOLS
[0288]
　11 Perspective Betsuoto field generating apparatus, 21 far sound field processing unit, 22 a gain adjustment unit, 23 filter unit, 24 near sound field processing unit, 25 a gain adjustment unit, 26 filter unit, 28 a speaker array, 41 sound field boundary control unit , 42 distant sound reproducing filter coefficient recording unit, 43 filter coefficient selection unit, 51 sound field boundary control unit 52 near sound reproducing filter coefficient recording unit, 53 filter coefficient selection unit, 91 a speaker array

The scope of the claims
[Requested item 1]
　By performing the filtering process using the distant sound reproduction filter coefficient for the first sound source signal, and far filter unit which generates a far sound reproduction signal for reproducing sound in the far listening area,
　the second sound source signal a neighborhood filter unit for generating a near sound reproducing signal for reproducing sound in different neighborhood listening area and by performing a filtering process using the near sound reproducing filter coefficients, the far listening area with respect to
　the signal processing with a apparatus.
[Requested item 2]
　The neighboring sound reproduction signal is a signal for generating the evanescent wave
　signal processing apparatus according to claim 1.
[Requested item 3]
　Further comprising a near sound field processing unit for determining the attenuation factor of the evanescent wave in accordance with a boundary position between the far listening area and the vicinity listening area,
　the neighboring filter unit, among a plurality of the neighboring sound reproducing filter coefficients performs filtering using the near sound reproducing filter coefficients corresponding to the determined said attenuation factor of the
　signal processing apparatus according to claim 2.
[Requested item 4]
　The far listening area and further comprising a near sound field processing unit for determining the position of the control point in response to the boundary position between the neighboring listening area,
　the determination of one of the neighboring filter unit, a plurality of the neighboring sound reproducing filter coefficients It performs filtering using the near sound reproducing filter coefficient corresponding to the position of the control point which is
　a signal processing apparatus according to claim 1.
[Requested item 5]
　Further comprising a far sound field processing unit for determining the position of the control point in response to the boundary position between the far listening area and the vicinity listening area,
　the determination of one of the distal filter section, a plurality of the distant sound reproducing filter coefficients It performs filtering using the distant sound reproduction filter coefficient corresponding to the position of the control point which is
　a signal processing apparatus according to claim 1.
[Requested item 6]
　The distant sound reproduction signal is a signal for generating a propagating wave
　signal processing apparatus according to claim 1.
[Requested item 7]
　And far sound field processing unit for determining a gain in accordance with the boundary position between the far listening area and the vicinity listening area,
　the gain adjustment on the basis of the determined the gain first sound source signal or the distant sound reproduction signal and far gain adjustment unit which performs
　signal processing apparatus according to claim 1, further comprising a.
[Requested item 8]
　And neighborhood sound field processing unit for determining a gain in accordance with the boundary position between the far listening area and the vicinity listening area,
　the gain adjustment on the basis of the determined the gain second sound source signal or the near sound reproducing signal and the neighboring gain adjustment unit which performs
　signal processing apparatus according to claim 1, further comprising a.
[Requested item 9]
　Wherein the first sound signal and the second sound source signal is a signal for reproducing sound having different contents
　signal processing apparatus according to claim 1.
[Requested item 10]
　Further comprising a speaker array for reproducing sound based on a signal obtained by combining the near sound reproducing signal and the far sound reproduction signal
　signal processing apparatus according to claim 1.
[Requested item 11]
　A first loudspeaker array for reproducing sound on the basis of the distant sound reproduction signal,
　and a second speaker array for reproducing sound based on the proximity sound reproduction signal
　signal processing apparatus according to claim 1, further comprising a.
[Requested item 12]
　Sound based on the distant sound reproduction signal is reproduced at a timing different from that of the sound based on the proximity sound reproduction signal
　signal processing apparatus according to claim 1.
[Requested item 13]
　Sound based on the distant sound reproduction signal is the sound for masking sound based on the proximity sound reproduction signal
　signal processing apparatus according to claim 1.
[Requested item 14]
　Further comprising a sound field boundary control unit which determines the boundary position between the far listening area and the vicinity listening area based on the listener's position in space
　signal processing apparatus according to claim 1.
[Requested item 15]
　By performing the filtering process using the distant sound reproduction filter coefficients for the first excitation signal to generate a distant sound reproduction signal for reproducing sound in the far listening area,
　near the second sound source signal by performing the filtering process using the sound reproduction filter coefficients, generates a near sound reproducing signal for reproducing sound in different neighborhood listening region and the far listening area
　signal processing method comprising the steps.
[Requested item 16]
　By performing the filtering process using the distant sound reproduction filter coefficients for the first excitation signal to generate a distant sound reproduction signal for reproducing sound in the far listening area,
　near the second sound source signal by performing the filtering process using the sound reproduction filter coefficients, it generates a near sound reproducing signal for reproducing sound in different neighborhood listening region and the far listening area
　program for executing the processing including a step in the computer.