Technical field
[0001]
　This technology sound field forming apparatus and method, and a program, with a smaller amount of calculation sound field forming apparatus and method capable of improving the reproducibility of the wavefront, and a program.
BACKGROUND
[0002]
　For example, you have multiple listeners within space, if you want to hear different sounds in each, can listen to the sound in which a plurality of the listener are different by using the directivity control technique.
[0003]
　As a method of performing such directivity control, a method using a parametric speaker is known (e.g., see Non-Patent Document 1).
[0004]
　However, in the method using a parametric speaker, the number of direction of the sound to be presented must be prepared parametric speaker, also unable to control the sound field in the depth direction relative to the parametric loudspeaker. Furthermore, it is not possible to form a specific sound field, such as a point source and plane wave, as compared with ordinary speaker, since the sound quality of sound output from the parametric speaker is not good, the content to be reproduced is limited.
[0005]
　In contrast, by using the speaker array, and directivity by the signal processing, it is possible to change the number of sound to be reproduced adaptively. In addition to the directivity control it is also possible the formation of a point source and plane wave by the wave field synthesis techniques. With these sound field, it is possible to provide a specific sound field to a particular listener.
CITATION
Non-patent literature
[0006]
Non-Patent Document 1: Kamakura other, "practical use of the parametric speaker," Acoustical Society of Japan Journal, vol.62, p.791-797, 2006.
Summary of the Invention
Problems that the Invention is to Solve
[0007]
　Incidentally, in the sound field using a speaker array, usually, it is higher in reproducibility of the sound field with more speakers.
[0008]
　However, when providing different sound field into a plurality of listeners, reduces the reproducibility of the wavefront interfere with each other wavefront generated in order to hear the sound for each listener is reproduced for listener sound not only, you will also hear leaking sound that is played to the other of the listener. Further, when the greater the number of speakers constituting the speaker array, becomes much amount of calculation that much convolution process.
[0009]
　This technology has been made in view of such circumstances, it is desirable to make it possible to improve the reproducibility of the wavefront with a smaller amount of calculation.
Means for Solving the Problems
[0010]
　Sound field apparatus according to an embodiment of the present technology, a listener position acquisition unit that acquires listener position information indicating the position of the listener, based on the listener position information of the speakers constituting the speaker array and driving the speaker selection section for selecting one or more speakers to be used for formation of the sound field as a driving speakers, in accordance with the selection result of the driving speaker, the speaker drive for forming the sound field by driving the driving speaker and a drive signal generator for generating a signal.
[0011]
　It said speaker driving signal may be a signal for forming the sound field by the wave field synthesis.
[0012]
　Wherein the drive signal generator, the for said drive speaker of the speakers constituting the speaker array only, it is possible to generate the loudspeaker drive signal by convoluting the filter coefficients and the excitation signal.
[0013]
　The sound field forming apparatus, a filter coefficient recording unit for recording the filter coefficient for each speaker of the speaker array can be further provided.
[0014]
　Wherein the driving speaker selection section, in the speaker array in a direction parallel, a speaker located in the vicinity of the listener can be selected as the driving speaker.
[0015]
　Wherein the driving speaker selection section, in the speaker array in a direction parallel, a speaker located in the sound source near generated by formation of the sound field can be selected as the driving speaker.
[0016]
　Wherein the driving speaker selection section, wherein the speaker array perpendicular direction, and the listener is such that the number is a number of the driving speaker The more distant position from the speaker array can be selectively said driving speaker .
[0017]
　Wherein the driving speaker selection section, when selecting the drive speaker for each of the listener or listener group, as the listener or listener group is large, the driving speaker to be selected for the listener or listeners group so that the number of decreases, it is possible to select the driving speaker.
[0018]
　Wherein the driving speaker selection section, it is possible to select the drive speaker in accordance with the forming method of the sound field.
[0019]
　Sound field method or a program according to an embodiment of the present technology, and obtains the listener position information indicating the position of the listener, based on the listener position information, form of the sound field of the loudspeaker constituting a speaker array one or more speakers selected as driving speakers used, depending on the selection result of the driving speaker, comprising the steps of generating a loudspeaker drive signal for forming the sound field by driving the driving speaker.
[0020]
　In one aspect of the present technique, the acquired listener position information indicating a position of the listener, based on the listener position information, one or more used in the formation of the sound field of the loudspeaker constituting a speaker array speaker is selected as the driving speakers, in accordance with the selection result of the driving speaker, the speaker drive signal for forming the sound field by driving the driving speaker is generated.
Effect of the invention
[0021]
　According to the embodiments of the present technology, it is possible to improve the reproducibility of the wavefront with a smaller amount of calculation.
[0022]
　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
[0023]
[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 the sound field forming apparatus.
Is a diagram illustrating FIG. 4 coordinate system.
5 is a diagram for explaining the selection of the driving speaker.
6 is a diagram illustrating the selection of the driving speaker.
7 is a diagram for explaining the selection of the driving speaker.
8 is a diagram for explaining the selection of the driving speaker.
It is a flowchart illustrating a FIG. 9 sound field processing.
It is a diagram illustrating a configuration example of FIG. 10 computer.
DESCRIPTION OF THE INVENTION
[0024]
　Hereinafter, with reference to the accompanying drawings, a description will be given of an embodiment according to the present technology.
[0025]

　This technique, by selecting the speaker to drive the among the speakers constituting the speaker array in accordance with the listener's position and number, sound field forming method, reducing the effect on the other sound field forming sound field, it is to be able to improve the reproducibility of the wavefront with a smaller amount of calculation.
[0026]
　For example, the formation of the sound field to hear the sound that heard by some listeners, the use of only a part of the speaker rather than driving all speakers constituting the speaker array, to generate a speaker drive signal it is possible to reduce the amount of calculation of the convolution required processing.
[0027]
　Furthermore, even without using all of the speakers for forming a sound field, using the speakers arrayed in long enough, the wavefront of the sound can be formed with sufficient reproducibility. That is, it is an error of the ideal wavefront form sufficiently small wavefront.
[0028]
　For example cage is listener LSN11 and listener LSN12 the listening area as shown in FIG. 1, using a speaker array SPA11, and to hear the different sounds for these listeners by wavefront synthesis. Specifically, let the sound of the content A is the listener LSN11, and to hear the sound of the content B to the listener LSN12.
[0029]
　In this case, for example, at the same time it drives the entire speaker constituting the speaker array SPA11 as indicated by the arrow Q11 form a wavefront of the sound of the content A and drives the entire speaker constituting the speaker array SPA11 content B sound and the formation of the wavefront.
[0030]
　In such a case, the amplitude of the wave front of the sound of the content B has, for example, the listener sufficiently large even region R11 at the position close to LSN11, the wavefront of the sound of the content A is a being affected by the wavefront of the sound of the content B , reproducibility of the wave front of the sound of the content a is lowered. That is, the wave front of the sound wavefront and content B of the sound of the content A is interfering.
[0031]
　In this case, the listener LSN11, but the sound of the reproduced content A can be heard towards the own, also will be heard leaking sound of the content B reproduced towards the listener LSN12.
[0032]
　Similarly, the amplitude of the wave front of the sound of the content A has, for example, the listener sufficiently large even region R12 at the position close to LSN12, becomes the wavefront of the sound of the content B is affected by the wavefront of the sound of the content A, content reproducibility of the wave front of the sound of B is lowered.
[0033]
　Therefore, in this technology, for example, among the speakers constituting the speaker array SPA11 as indicated by the arrow Q12, and to select a speaker to be used for formation of the wavefront of the sound of each content.
[0034]
　In this example, among the speakers constituting the speaker array SPA11, in the figure, and only five loudspeakers arranged on the left side is driven to form a wavefront of the sound of the content A. Also, among the speakers constituting the speaker array SPA11, in the drawing, thereby forming the wave front of the sound of the content B by driving only ten speakers arranged in the right side.
[0035]
　In this way, to improve the wave front of the sound of the content A, it can be suppressed that the wave front of the sound of the content B interfere with each other, the wave front of the reproducibility of sound during sound field can. That is, it is possible to reduce the error in the wavefront that is actually formed and the ideal wavefront.
[0036]
　In forming the wavefront of the sound of the content A and content B, and is used a part of a speaker that constitutes a speaker array SPA11, the wavefront at a sufficient reproducibility Longer array length of the speaker array consisting of speaker enough it can be formed.
[0037]
　The wave field synthesis, usually a speaker monopole characteristics, i.e. it is assumed that the omnidirectional properties wavefront spreads equally sound in all directions, the actual characteristics of the loudspeaker there is an error. Deviation from the monopole characteristics as a speaker at the position of the end of the speaker array increases, especially when viewed from the listener, but the error in the formation sound field arises, by driving only the loudspeaker required, the influence of the speaker characteristic error it is reduced, thereby improving the reproducibility of the wavefront.
[0038]
　Also, by driving only the loudspeaker necessary, it is possible to reduce the amount of calculation of the convolution processing than using whole speaker of the speaker array SPA11.
[0039]
　For example, to generate a total point sound source by driving the speaker of the speaker array SPA11, is required amount corresponding filter coefficients when the first speaker and one channel (channel number) × (point source position number). However, by selectively driving only the loudspeaker necessary, it is possible to reduce the number of filter coefficients used for the operation by that amount. Thus, it is possible to reduce the amount of computation of the convolution processing.
[0040]
　For example, as shown in FIG. 2, and was sound field so that a predetermined sound source AS11 is generated using a speaker array SPA11. Note that portions corresponding to the case in FIG. 1 in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted as appropriate. Further, in FIG. 2, shading of each position indicates the sound pressure of formation sound field.
[0041]
　By driving all speakers constituting the speaker array SPA11 as indicated by the arrow Q21 in FIG. 2, and to form a sound field reproducing sound of the content B. In the content B, a sound source of the sound has become a sound source AS11, sound source AS11 is located in front of the listener LSN12 to hear the sound of the content B.
[0042]
　In this case, the position of the listener LSN12 have sufficient sound pressure is ensured, the listener LSN12 can hear the sound of the content B in sufficient volume. However, because of sufficiently large sound pressure even at the position of the listener LSN11, you would hear the sound of unintended content B to the listener LSN11.
[0043]
　In contrast, among the speakers constituting the speaker array SPA11 as indicated by the arrow Q22, right side in the figure, that is to drive the only speaker in the listener LSN12 or sound AS11 side, a speaker array consisting of speaker and used as a speaker array SPA11 '. In this case, sounds the sound of the content B in sufficient sound pressure for the listener LSN12, low sound pressure at the position of the listener LSN11, the listener LSN11 adapted sound of the content B can not hear almost it can be seen.
[0044]
　As described above, in the case of first to different sounds to a plurality of listeners, for each listener, by only selectively driven part of the speaker of the speakers constituting the speaker array, a smaller amount of calculation in it is possible to improve the reproducibility of the wave front of the sound.
[0045]

　The following describes a more specific embodiment of the present technology described in the above.
[0046]
　Figure 3 is a diagram showing a configuration example of the sound field forming device employing the present technology.
[0047]
　Sound field forming apparatus 11 shown in FIG. 3 includes a listener position acquisition unit 21, the driving speaker selection section 22, acoustic filter coefficient recording unit 23, the acoustic filter 24 and the speaker array 25,.
[0048]
　Listener position acquisition unit 21 acquires a listener position information indicating the position of a listener who is listening area is a space to form a sound field, and supplies the driving speaker selection section 22.
[0049]
　Driving speaker selection section 22, based on the listener position information supplied from the listener position acquisition unit 21, and the formation method information showing the formation method of the supplied sound field from the outside, speaker constituting the speaker array 25 among speakers used for sound field, that selects the loudspeaker to be driven. Then, driving speaker selection unit 22 generates a drive speaker information indicating the selection result of the speaker for driving is supplied to the acoustic filter coefficient recording unit 23. Hereinafter, selected by driving speaker selection section 22, a speaker used in the sound field will be referred to both the driving speaker.
[0050]
　Here, for each each listener or a group comprising a plurality listener (listener group), from among the speakers constituting the speaker array 25, the wavefront of the sound to hear their listener or group, that is the sound presented one or more speakers to be used for forming the field is selected as the driving speaker. Then, information indicating the driving speaker is selected is generated as the driving speaker information.
[0051]
　In the following, for simplicity of explanation, the description will be continued assuming that driving speaker is selected for each listener.
[0052]
　Acoustic filter coefficient recording unit 23, for each forming method of the sound field, is recorded in advance the filter coefficient of the acoustic filter for forming a predetermined sound field.
[0053]
　Acoustic filter coefficient recording unit 23, forms format information supplied from the outside, and on the basis of the driving speaker information supplied from the driving speaker selection section 22, the sound field from a plurality of filter coefficients prerecorded select the filter coefficients used, and supplies the acoustic filter unit 24.
[0054]
　The acoustic filter unit 24, a sound source signal of the sound to be reproduced is supplied. That is, when to hear the sound of different content for each listener who is for example the listening area, for each of those contents, the sound source signal for reproducing the sound of content is supplied to the acoustic filter unit 24. Further, for example, for each of a plurality of listeners, when to hear the sound of the same content at different times, the sound source signal to reproduce the sound of the piece of content is supplied to the acoustic filter unit 24.
[0055]
　Acoustic filter unit 24, for each drive speakers, and the sound source signal supplied from the outside, by convoluting a filter coefficient supplied from the acoustic filter coefficient recording unit 23, a speaker drive signal for forming a desired sound field generated, supplied to the speaker array 25. That is, the acoustic filter 24, depending on the choice of driving the speaker results in accordance with driving speaker selection section 22, for driving the speaker of the speakers constituting the speaker array 25 only by performing the convolution processing of the sound source signal and filter coefficients functions as a driving signal generation unit for generating a speaker drive signal.
[0056]
　Speaker driving signal generated in this way, for example, by driving the driving speakers, a signal for forming a desired sound field by wavefront synthesis.
[0057]
　Speaker array 25, for example, a plurality of speakers and the linear loudspeaker array which are arranged in a straight line, a plurality of speakers planar speaker array arranged in a planar, a plurality of annular speaker array in which speaker is arranged in a circular shape, a plurality speaker and the like spherical speaker array arranged in spherical. Incidentally, the speaker array 25, as long as it is obtained by arranging a plurality of speakers, may be any speaker array.
[0058]
　Speaker array 25 forms a sound field by reproducing a sound based on the speaker drive signal supplied from the acoustic filter unit 24. That is, more specifically, that each driving speakers of the speaker array 25 outputs a sound based on the supplied loudspeaker drive signal, the sound field is formed by, for example, wavefront synthesis.
[0059]
　Here, the coordinate system used in the description of the following description with reference to FIG. Note that portions corresponding to the case in FIG. 3 in FIG. 4 are given the same reference numerals, and description thereof will be omitted as appropriate.
[0060]
　That is, in the description of the following, the central position of the speaker array 25 is the origin O of the three-dimensional orthogonal coordinate system.
[0061]
　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 25. The direction of the y-axis, i.e. the y direction is the x direction and the perpendicular direction, and is a direction parallel to the direction in which sound waves are output from the speaker array 25, these x and y directions perpendicular direction z axis, i.e. it is the z-direction. In particular, the direction of sound waves from the speaker array 25 is output is the positive direction of the y-direction.
[0062]
　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. The coordinates (x, y, z) positions indicated by, and also referred to as a position v.
[0063]
　Further, the speaker array 25 and the linear loudspeaker array, the planar speaker array, cyclic speaker array, may be of any type spherical speaker array or the like, continued described as the speaker array 25 is a linear loudspeaker array below .
[0064]
(Listener position acquisition unit)
　Next, each section of the sound field forming device 11 shown in FIG. 3 will be described in more detail. First, a description will be given listener position acquisition unit 21.
[0065]
　Listener position acquisition unit 21, for example, every listener who is listening area, obtains the information indicating the position of the listener as the listener position information.
[0066]
　For example the listener position acquisition unit 21, may be obtained or is supplied from an external device, the information indicating the position of the listener with or input by the user or the like as the listener position information.
[0067]
　Further, for example, the listener position acquisition unit 21, the number of the listener, by generating information indicating the position of a listener for each detecting the position of those of the listener and the listener, the listener position that information it may be obtained as information.
[0068]
　In such a case, the listener position acquisition unit 21, for example a camera for photographing the listener as a subject, a pressure-sensitive sensor disposed on the floor portion of the space are the listener detects the distance to the listener by ultrasonic or the like such as configured from the distance sensor to be. In this case, the listener position acquisition unit 21 recognizes the listener by using cameras and pressure sensor, a distance sensor, etc., it calculates the position of the listener on the basis of the recognition result.
[0069]
　Specifically, for example, the listener position acquisition unit 21, from the image captured by the camera to detect the listener by object recognition or the like using a dictionary, listener position indicating a position of each listener from the detection result to generate the information.
[0070]
　Incidentally, when the distance between the plurality of the listener is closer than a predetermined fixed distance may be treated their human listener as a group. In this case, the position and typical listener in the group, the average value of the position of each listener in the group and the like, are listener position information when considers the group as one of the listener.
[0071]
(Driving speaker selection section)
　driving speaker selection section 22, based on the listener position information and formation method information, selects a speaker for driving of the speakers constituting the speaker array 25.
[0072]
　Here, formation method information is information indicating a forming method for forming a sound field. More specifically, formation method information are, for example, information including wavefront forming technique for forming the wavefront of the sound, i.e. the type of formation technique of the sound field, information indicating the kind of the sound field to form such a point source and plane wave .
[0073]
　Driving speaker selection section 22, based on the listener position information and formation method information, but selects the driving speaker selection of driving the speaker is performed as follows, for example.
[0074]
　That is, the listener LSN21 and listener LSN22 Guile in front of the speaker array 25 in the listening area as shown in FIG. 5, for example. Note that portions corresponding to the case in FIG. 3 in FIG. 5 are denoted by identical reference numerals, and description thereof will be omitted as appropriate.
[0075]
　In this example, the listener position information, it is possible to specify the position of the listener LSN21 and listener LSN22. In this case, driving speaker selection unit 22, for example, the listener LSN21 finds the y direction of the straight line L11 connecting the listener LSN21 and the speaker array 25, the closest speaker at the intersection of the straight line L11 and the speaker array 25 a center speaker.
[0076]
　The driving speaker selection section 22 selects the center speaker predetermined number of speakers arranged in the x direction around, as speaker group SPG11 made of, for example, a plurality of speakers from the driving speaker for the listener LSN21.
[0077]
　Such speaker set SPG11 selected in the are located in front of the listener LSN21, i.e. around the speaker located in the y direction as viewed from the listener LSN21, consisting symmetrical one or more number of speakers a speaker group. In this example, a direction parallel to the speaker array 25, i.e. in the x direction, a speaker located near the listener LSN21 (near) will be selected as the driving speaker.
[0078]
　Thus a speaker positioned in front of the listener LSN21, i.e. the use of the speaker in the vicinity listener LSN21 as driving speakers, at the time of forming the sound field to be presented to the listener LSN21 by wavefront synthesis, listener LSN21 it is possible to form the wavefront of the sound at a sufficiently high reproducibility at a position. Especially when forming a wave front of the sound in the speaker array, the repeatability of the wavefront as near the center of the speaker array is increased, if the center position of the array of the front of the listener LSN21 from driving the speaker, the reproducibility of the wavefront it is possible to improve the.
[0079]
　Similar to the listener LSN21 also listener LSN22, driving speaker selection section 22, the y-direction of the straight line L12 connecting the listener LSN22 the speaker array 25 determined, the intersection of the straight line L12 and the speaker array 25 centered speaker closest speaker. The driving speaker selection section 22, a predetermined number of speakers arranged in the x direction around the center speaker is selected as the speaker group SPG12 consisting driving speakers for the listener LSN22.
[0080]
　Here, as each of driving the speaker of the listener LSN21 and listener LSN22 varies speaker for each listener is selected, it may be a single speaker is used as the driving speakers of the plurality of listeners . Conversely, it may be a single speaker so as not to be selected as the driving speakers of the plurality of the listener to select a driving speakers of each listener. In such a case, the listener to be able to suppress the interference of the sound to hear, the reproducibility of the wave front of the sound can be further improved.
[0081]
　Further, for example, not only the position of the listener as shown in FIG. 6, the position of the sound source generated during sound field may be to select a drive speaker considered. Note that portions corresponding to the case in FIG. 5 in FIG. 6 are denoted with the same reference numerals, and description thereof will be omitted as appropriate.
[0082]
　In this example, cage is listener LSN21 and listener LSN22 the listening area, to generate a sound source AS21 when sound field for the listener LSN21, and to hear the sound of the sound source AS21 the listener LSN21. In addition, to generate a sound source AS22 when the sound field for the listener LSN22, and to hear the sound of the sound source AS22 to the listener LSN22. For example, the position of the sound source AS21 or sound AS22 may also be included and may be configured to be a predetermined position, information indicating the positions of the sound source formation method information.
[0083]
　In this case, driving speaker selection unit 22, for example, the listener LSN21 obtains a straight line L21 connecting the listener LSN21 and the sound source AS21, center speaker closest speaker at the intersection of the straight line L21 and the speaker array 25 to. The driving speaker selection section 22, a predetermined number of speakers arranged symmetrically in the x-direction around its center speaker is selected as the speaker group SPG21 consisting driving speakers for the listener LSN21.
[0084]
　Therefore, a direction parallel to the speaker array 25 in this example, i.e. in the x direction, a speaker located near (near) of the listener LSN21 and sound AS21 is to be selected as the driving speaker.
[0085]
　When generating a sound source AS21 by driving the plurality of speakers by wavefront synthesis (formation), as the speaker is positioned closer to the sound source AS21, contribution to the generation of the sound source AS21 is high should. Therefore, by selecting a speaker located closer to the listener LSN21 or sound AS21 as driving speakers, it can be even with a small number of speakers to form a wavefront with sufficient reproducibility.
[0086]
　Similar to the listener LSN21 also listener LSN22, driving speaker selection section 22 obtains a straight line L22 connecting the listener LSN22 and the sound source AS 22, the closest speaker at the intersection of the straight line L22 and the speaker array 25 a center speaker. The driving speaker selection section 22, a predetermined number of speakers arranged symmetrically in the x-direction around its center speaker is selected as the speaker group SPG22 consisting driving speakers for the listener LSN22.
[0087]
　The number of speakers is selected as the drive speaker may be a predetermined number, and distance in the y direction between the speaker array 25 and the listener, such as the slope of the straight line connecting the position of the sound source and the listener it may be a number of variable determined according. Example, as the slope of the straight line connecting the position of the sound source and the listener is large, if so using more loudspeakers as driving speakers, selects the appropriate number of speakers to form a wavefront with sufficient reproducibility be able to. Further, for example, as the distance in the y direction between the listener and the speaker array 25 is short, it may be the number of driving the speaker is reduced.
[0088]
　Furthermore, here has been described the case of forming a sound field by wavefront synthesis as an example, for example, from the selected speaker as driving speakers, it may be caused to output the same sound at the same time. In this way, not only can reduce the amount of calculation when performing the filtering process or the like for each speaker when generating the loudspeaker drive signal, the reproduced sound to hear a given listener, let the other listener it is possible to suppress the fact that the sound that will be mixed.
[0089]
　Further, selected as another example of the selection method of driving the speaker, for example, y-direction ratio of the distance between the listener and the speaker array 25, as shown in FIG. 7, that is, the driving speakers according to the ratio of the distance in the depth direction it may be so. Note that portions corresponding to the case in FIG. 5 in FIG. 7 are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
[0090]
　In the example shown by the arrow Q31 in FIG. 7, cage is listener LSN21 and listener LSN22 the listening area, a y-direction distance y1 from the speaker array 25 to listener LSN21, y direction from the speaker array 25 to listener LSN22 the ratio of the distance y2 of y1: y2 = 1: has a 2.
[0091]
　Therefore, driving speaker selection section 22 includes a number of drive speakers for forming the wavefront of the sound to hear against the listener LSN21, drive speakers for forming the wavefront of the sound to hear against the listener LSN22 the ratio between the number selects the driving speaker to be 1 to 2 which is the ratio of the distance y1 and distance y2. That is, in the y-direction is a direction perpendicular to the speaker array 25, as the listener as viewed from the speaker array 25 is in a position far, the selection of the driving speaker so that the number of driving loudspeakers that is selected for its listener increases It is carried out.
[0092]
　In this example, in front of the listener LSN21, 5 pieces of speakers arranged continuously in the x direction is selected as the speaker group SPG31 consisting driving speakers for the listener LSN21. In contrast, in front of the listener LSN22, 10 pieces of speakers arranged continuously in the x direction is selected as the speaker group SPG32 consisting driving speakers for the listener LSN22.
[0093]
　Thus not only to select the position of the speaker close to the listener as driving speakers, depending on the ratio of the distance from the speaker array 25 of the listener, by determining the number of drive speakers assigned to each listener, it is possible to form a wavefront with sufficient reproducibility at the position of each listener.
[0094]
　For example, in this embodiment, one reference line RFL11 respect listener LSN21 and listener LSN22 is set. Wave-field synthesis is seen from the speaker array 25, since it is a technique for forming a sound field farther than the reference line RFL11, the reference line RFL11 is set in the vicinity of the listener LSN21 that are closer to the speaker array 25 in this example It is.
[0095]
　Because of the high reproducibility of the wavefront closer to the reference line RFL11 the wavefront synthesis, it is possible to form the wave surface with sufficient reproducibility with a small number of drive speakers for the listener LSN21 that in the vicinity reference line RFL11.
[0096]
　In contrast, since the listener LSN22 Are farther from the reference line RFL11, to ensure adequate repeatability of the wavefront, it is necessary to use more drive speakers. Therefore, the listener LSN22 is more speakers than listeners LSN21 used as the driving speaker.
[0097]
　Further, in the wave field synthesis can not generate a tone only the speaker array side from the reference line. Therefore, the like when generating source in the vicinity of the listener, for example may be designated the reference line for each listener as indicated by an arrow Q32.
[0098]
　In this example, the reference line RFL21 is specified for the listener LSN21, the reference line RFL22 are specified for the listener LSN22.
[0099]
　In this case, the speaker drive signal for forming a wavefront of the sound to hear against the listener LSN21 is generated a reference line RFL21 as a reference line, speaker group SPG31 is driven on the basis of the loudspeaker drive signal, listener the sound field to be presented to the LSN21 is formed. Thus, the position of the listener LSN21, sound from a sound source generated in the vicinity of that position is reproduced.
[0100]
　In contrast, speaker driving signal for forming the wavefront of the sound to hear against the listener LSN22 is generated a reference line RFL22 as a reference line, speaker group SPG32 is driven on the basis of the loudspeaker drive signal, sound field is formed.
[0101]
　By doing so, it is possible to generate a sound source near each of the listener LSN21 and listener LSN22.
[0102]
　Farther reference line from the speaker array 25, more drive speaker to form a wavefront required with sufficient reproducibility. Therefore, to set the reference line in the vicinity of the listener, and as in the case of generating a sound source in the vicinity of the listener, defines the number of drive loudspeakers by the ratio of the distance to the listener from the speaker array 25 if, it is possible to use an appropriate number of driving speakers for each listener. Thus, at the position of each listener, it is possible to form the wavefront of the sound with sufficient reproducibility.
[0103]
　Further, for example, when the speaker array 25 is a like flat speaker array, driving speaker selection section 22 is the listener's head height, i.e. may be selected to drive the speaker in accordance with the height of the ear .
[0104]
　More specifically, for example, if the speaker of the same height as the position of the listener's ear so as to select as the driving speakers, even if two of the listener to the height of the position of the ear are different in close proximity , it is possible to suppress the sound of each of those listeners may interfere.
[0105]
　Further, when the driving speaker for each listener is selected, for example, it may be determined a number of driving speakers of each listener in accordance with the number of the listener who is listening area as shown in FIG. Note that portions corresponding to the case in FIG. 3 in FIG. 8 are denoted by identical reference numerals, and description thereof will be omitted as appropriate.
[0106]
　For example, in the example shown in the arrow Q41, there are two listeners LSN31 and listener LSN32 the listening area. The driving speaker selection unit 22, the listener position information, it is possible to determine the number of listeners who are listening area.
[0107]
　In this case, driving speaker selection section 22 defines the number of speakers to be driven speaker for each listener based on the number of the listener "2" being in listening area. In this example, six speakers for each listener is used as the driving speaker.
[0108]
　That is, the driving speaker selection section 22 is located in front of the listener LSN31, six speakers arranged in the x-direction is selected as the speaker group SPG41 consisting driving speakers for the listener LSN31. Similarly, driving speaker selection section 22 in front of the listener LSN32, six speakers arranged in the x-direction is selected as the speaker group SPG42 consisting driving speakers for the listener LSN32.
[0109]
　Also, for example, if there are four of the listener LSN41 to listener LSN44 to the listening area as shown by the arrow Q42, driving speaker selection section 22 includes a drive speakers of each listener based on the listener number "4" determine the number of speakers to be. In this example, three speakers for each listener is used as the driving speaker.
[0110]
　That is, the driving speaker selection section 22 is located in front of the listener LSN41, three loudspeakers arranged in the x-direction is selected as the speaker group SPG51 consisting driving speakers for the listener LSN41. The driving speaker selection section 22 in front of the listener LSN42, three loudspeakers arranged in the x-direction is selected as the speaker group SPG52 consisting driving speakers for the listener LSN42. Similarly, driving speaker selection section 22 selects the speaker group SPG53 respect listener LSN43, selects the speaker group SPG54 respect listener LSN44.
[0111]
　Thus in accordance with the listener number by determining the number of drive loudspeakers used for each listener, that even if the listener large number may interfere sound that is reproduced for each listener it can be suppressed.
[0112]
　In particular, the more the listener who is listening area in this example, as the listener Number per drive the speaker is reduced, that is, selection of the driving speaker so that the number of driving speakers selected for the listener is reduced It takes place. This is the same case of selecting the driving speaker for each group of a plurality of listeners (listener group), as the number of groups is large, the number of driving speakers are selected for the group is made to be less .
[0113]
　Incidentally, the choice of the speaker as a drive speaker, may be determined by the method described with reference to FIGS. 5 and 6, for example.
[0114]
　Further, a method for determining the number of drive speaker by the number of the listener as described with reference to FIG. 8, for example, may be used in combination as the method described with reference to FIG. In such a case, for example, based on the ratio of y-direction distance from the speaker array 25 to each listener, proportion of the number of driving speakers each listener (ratio) is determined. Then, depending on the proportion of the number of the driving speaker, as the speaker of the speaker array 25 is not assigned to any one of or assigned to the listener, or any of the listener, that is, the same speaker plurality of persons as not assigned to the listener, driving speaker used for each listener are determined.
[0115]
　Since the distance in the x direction between the listener is likely also close, it may be the same speakers are different listener drive the speaker from each other. However, it is possible to possible increased when one speaker is to be used as a drive speaker one of the listener, the effect of suppressing interference of sound.
[0116]
　Furthermore, not only the listener location information when selecting the drive speakers, as appropriate, formed method information may be used. In other words, driving the speaker in response to the sound field forming scheme indicated by the formation method information may be selected.
[0117]
　For example forming method specific formation technique of the sound field represented by information, that is, as the sound field system, or method according to directivity control due delay sum, WFS (Wave Field Synthesis), by SDM (Spectral Division Method) Method method for generating a focus sound, or the like method of generating an evanescent wave.
[0118]
　For example, in the case of forming a sharp directivity of the sound field in the direction of the listener by the directivity control, it is not always necessary to use a speaker of the listener front as the driving speaker.
[0119]
　Therefore, for example, when selecting a drive speaker in the manner described with reference to such FIGS. 7 and 8 described above, in forming the sound field by the directivity control, the driving speaker selection unit 22 as a driving speakers of each listener the same speaker may not be selected. That is, for example, the front of the speaker driving speaker of each listener, when one speaker becomes a plurality of listeners of driving the speaker selects the speaker position shifted from the front of the listener as a drive speaker it is, it is possible to prevent the occurrence duplication of such driving speakers.
[0120]
　Further, for example, when the sound field by generating an evanescent wave is formed, it is necessary to select the speaker in front of the listener as a drive speakers.
[0121]
　Therefore, for example, when selecting a drive speaker in the manner described with reference to such FIGS. 5 and 6 described above, in forming the sound field by the production of evanescent waves, driving speaker selection section 22, the same speaker in several and allowed to be selected as the driving speaker of the listener, may be selected to drive the speaker of the listener.
[0122]
　Furthermore, for example, in the case of forming a sound field by SDM method, it is possible to form a sound field with a relatively small speaker than other approaches.
[0123]
　Therefore, for example, FIGS. 5 and 6, 7, when selecting the driving speaker in the manner described with reference to FIG. 8 or the like, when forming the sound field by SDM method, driving speaker selection section 22, the same speaker so as not to be selected as the driving speakers of the plurality of the listener, it may be selected to drive the speaker of the listener.
[0124]
　The selection method of driving the speaker is not limited to the examples described in the above, as long as it selects the drive speaker with at least listener position information, may be any method. Each method described in example above may be such as appropriately combined.
[0125]
(Acoustic filter coefficient recording unit)
　acoustic filter coefficient recording unit 23, from among the filter coefficients of the acoustic filter prepared in advance, to determine the filter coefficients used for generating the speaker drive signal.
[0126]
　That is, the acoustic filter coefficient recording unit 23, of the filter coefficients of the acoustic filter for forming a sound field in the manner indicated by the formation method information, indicated by a drive speaker information supplied from the driving speaker selection section 22 drives supplying only the filter coefficients of the speaker in the acoustic filter unit 24.
[0127]
　For example, if the sound field forming technique indicated by the formation method information is SDM method, acoustic filter coefficient recording unit 23, of the filter coefficients of each speaker constituting the speaker array 25 used in the SDM technique, indicated by the drive speaker information supplying only the filter coefficients of the driving speaker acoustic filter unit 24. Acoustic filter coefficient recording unit 23 selects the filter coefficient based on the formation method information and the driving speaker information for each listener, and supplies the selected filter coefficients to the acoustic filter unit 24.
[0128]
　Here, the filter coefficients of an acoustic filter used in SDM method, for example obtained as follows. It is to be noted that the SDM method, for example, "Sascha Spors and Jens Ahrens," Reproduction of Focused Sources by the Spectral Division Method, "4th International Symposium on Communications, Control and Signal Processing (ISCCSP), 2010." is described in detail in such ing.
[0129]
　For example, the sound field P (v, n in the three-dimensional free space tf ) is expressed as shown in the following equation (1).
[0130]
[Number 1]

[0131]
　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.
[0132]
　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 speaker driving signals of the speaker constituting the speaker array 25.
[0133]
　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).
[0134]
[Number 2]

[0135]
　In the equation (2), n sf represents the spatial frequency index.
[0136]
　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).
[0137]
[Number 3]

[0138]
　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 to match the sound field that is actually formed only on the reference line and the ideal sound field. 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).
[0139]
[Formula 4]

[0140]
　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.
[0141]
　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.
[0142]
[Formula 5]

[0143]
　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 filter coefficients does not depend on the sound source, where S (n tf are) = 1.
[0144]
　Further, the transfer function G F (n sf , y ref , 0, n tf ) can be expressed as shown in the following equation (6).
[0145]
[Number 6]

[0146]
　Or of formula (4), Equation (5), and (6) is used, the spatial frequency spectrum D of the speaker driving signals of the speaker array 25 F (n sf , n tf ) is determined.
[0147]
　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.
[0148]
[Number 7]

[0149]
　In the equation (7), l identifies the speaker constituting the speaker array 25 shows a speaker index of the position in the x direction of the speaker, M ds denotes the number of samples of DFT.
[0150]
　Moreover, the time-frequency spectrum D (l, n tf ) against, IDFT (Inverse Discrete Fourier Transform) is performed time-frequency synthesis using a loudspeaker drive signal for respective speakers of the speaker array 25 is a time signal d (l , N D ) is obtained. Specifically, by performing the calculation of equation (8), the speaker drive signal d (l, n d ) is calculated.
[0151]
[Number 8]

[0152]
　In Expression (8), n d denotes the time index, M dt denotes the number of samples of IDFT.
[0153]
　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 ) of time index n d a, those replaced with time index n, the position of the point source (x ps , y ps ) and the position of the control point y = y ref the filter coefficients of the acoustic filter obtained h (l, n) are.
[0154]
　Here, the one control point, the filter coefficients h (l, n) is determined for each speaker identified by the speaker index l of the speaker array 25. That is, the acoustic filter is composed of filter coefficients for each speaker constituting the speaker array 25 h (l, n).
[0155]
　Such filter coefficients h (l, n), the position of the point source (x optionally ps , y ps is recorded in the acoustic filter coefficient recording unit 23 sought) Gotoya, each position of the control point .
[0156]
　Further, for example, filter coefficients of an acoustic filter used in forming a sound field by generating an evanescent wave, for example, obtained as follows. It is to be noted that the method of forming a sound field by evanescent wave, for example, "Itou et al." EVANESCENT WAVE REPRODUCTION USING LINEAR ARRAY OF LOUDSPEAKERS, "in IEEE Workshop on Applications of Signal Processing to Audio and Acoustics (WASPAA), 2011." It is described in detail in such.
[0157]
　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).
[0158]
[Number 9]

[0159]
　Note that c in formula (9) shows the speed of sound, ∇ 2 is as shown in the following equation (10).
[0160]
[Formula 10]

[0161]
　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).
[0162]
[Number 11]

[0163]
[Number 12]

[0164]
　In the equation (11) and Equation (12), j denotes an imaginary unit, omega represents the angular frequency.
[0165]
　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.
[0166]
[Formula 13]

[0167]
[Number 14]

[0168]
　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.
[0169]
[Number 15]

[0170]
　In the equation (15) [delta] (omega-omega pw ) show a delta function.
[0171]
　Here, in the wave number region, the relationship is established in the following equation (16).
[0172]
[Number 16]

[0173]
　Wavenumber k of equation (16) y-direction pw, y is solved for, as shown in the following equation (17).
[0174]
[Formula 17]

[0175]
　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.
[0176]
　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).
[0177]
[Equation 18]

[0178]
　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.
[0179]
　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.
[0180]
　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 increases.
[0181]
[Number 19]

[0182]
　Now consider the determination of the filter coefficients of the acoustic filter in order to obtain a loudspeaker drive signal for generating an evanescent wave of the formula (18).
[0183]
　If equation (18) for spatially Fourier transform for x, is expressed as shown in equation (20).
[0184]
[Number 20]

[0185]
　Further, the spatial frequency spectrum G of the transfer function '(k x , y, z, omega) is expressed as shown in the following equation (21).
[0186]
[Number 21]

[0187]
　Incidentally, H in the formula (21) 0 (2) shows a second kind Hankel function, K 0 denotes the Bessel function.
[0188]
　Furthermore, from SDM method using equations (20) Equation (21), the spatial frequency spectrum D '(k loudspeaker drive signal x , omega) is as shown in the following equation (22).
[0189]
[Equation 22]

[0190]
　In the formula (22), y ref represents the position of the control point as a reference in the y-direction.
[0191]
　The thus obtained formula (22), the wave number k x by inverse spatial Fourier transform on the time-frequency spectrum D (x, omega) of the loudspeaker drive signal shown in the following equation (23) is obtained.
[0192]
[Number 23]

[0193]
　Furthermore, this manner to inverse temporal Fourier transform and the resulting time-frequency spectrum D (x, ω), the time waveform d of the speaker drive signal as shown in the following equation (24) (x, t), i.e. the time signal speaker drive signal d (x, t) is is obtained.
[0194]
[Number 24]

[0195]
　At this time, to identify the speaker constituting the speaker array 25, when the index of the position in the x direction of the speaker and l, as shown in the following equation (25), the index of the acoustic filter from equation (24) l filter coefficients h (l, n) of the speaker is obtained.
[0196]
[Number 25]

[0197]
　In the equation (25), n denotes the time index. The filter coefficients h (l, n), as well as replacing the x in the speaker drive signal d shown in equation (24) (x, t) to the index l, obtained by replacing t the time index n. The acoustic filter coefficient recording unit 23, the thus obtained filter coefficients h (l, n) is recorded in advance.
[0198]
　Further, in the above, obtains the evanescent wave in the wave number region, the filter coefficients h (l, n) has been described the method of calculating the may be calculated filter coefficients to generate an evanescent wave in any other way .
[0199]
　The acoustic filter coefficient recording unit 23, as described above, and the filter coefficients used by the SDM method, such as a filter coefficient for forming a sound field by evanescent waves, to form a sound field 1 or for each of the plurality of methods filter coefficients are recorded.
[0200]
(Acoustic filter section)
　The acoustic filter unit 24, the sound source signal x of the sound to be reproduced (n) are supplied. Here, n in the source signal x (n) represents the time index.
[0201]
　Acoustic filter unit 24 includes a supply source signal x (n), the filter coefficients supplied from the acoustic filter coefficient recording section 23 h (l, n) convolved a speaker drive signal d (l, n) and Ask. That is, the acoustic filter 24, it is performed the calculation of equation (26) for each driving the speaker of the speakers constituting the speaker array 25, the speaker drive signal of the drive speaker identified by the speaker index l d ( l, n) is calculated.
[0202]
[Number 26]

[0203]
　In the equation (26), N denotes the filter length of the acoustic filter.
[0204]
　Further, in the driving speaker selection section 22, when the driving speaker for each listener is selected, from the acoustic filter coefficient recording unit 23, the filter coefficients of the acoustic filter h (l, n) is supplied to each listener that. In such a case, the acoustic filter unit 24 obtains a speaker drive signal d (l, n) of each driving speakers for each listener, determining a final speaker driving signal. In this case, for example, when one speaker is a plurality of listeners of driving speakers, speaker driving signals for each listener calculated for the speaker is summed and the final speaker driving signals .
[0205]
　Acoustic filter unit 24, the final speaker driving signal obtained as described above is supplied to the speaker array 25.
[0206]

　Next, the operation of the sound field forming apparatus 11 described in the above. That is, below with reference to the flowchart of FIG. 9 will be described sound field processing by the sound field forming apparatus 11.
[0207]
　In step S11, the listener position acquisition unit 21 supplies the driving speaker selection unit 22 acquires the listener position information.
[0208]
　In step S11, for example, or supplied from an external device, information indicating the position of each listener in the listening area or input by the user or the like, is obtained as the listener position information. Further, for example, object recognition with respect to the camera by the photographed image as a listener position acquisition unit 21, such as by detection by the pressure sensor of the listener as the listener position acquisition unit 21 as the position of the listener is required it may be.
[0209]
　In step S12, driving speaker selection unit 22, the listener position information supplied from the listener position acquisition unit 21, and on the basis of the supplied forming method information from the outside, and select the drive speaker for each listener, the generating a driving speaker information indicating the selection results.
[0210]
　For example, in step S12, FIG. 5 or FIG. 6, FIG. 7, the driving speaker for each listener is selected by a method such as that described with reference to FIG. 8 or the like. Driving speaker selection section 22 supplies a drive speaker information generated by selecting the drive speaker acoustic filter coefficient recording unit 23.
[0211]
　In step S13, acoustic filter coefficient recording unit 23, from among a plurality of filter coefficients based on a drive speaker information supplied form mode information supplied from the outside, and a driving speaker selection section 22, and prerecorded select a filter coefficient for each listener, and supplies the acoustic filter unit 24. In this case, for each listener, forming method of the filter coefficients of all the speakers of the speaker array 25 used in the sound field method shown by the information, only the filter coefficients of the driving speaker indicated by driving the speaker information is selected and sound It is supplied to the filter unit 24.
[0212]
　In step S14, the acoustic filter 24, for each listener obtains a loudspeaker drive signal by convoluting the excitation signal supplied from the outside, and a filter coefficient supplied from the acoustic filter coefficient recording unit 23, for each listener obtaining a final speaker drive signal from the speaker drive signal obtained in.
[0213]
　That is, in step S14, the calculated speaker drive signal computation performed by each speaker of the formula (26) described above is a speaker driving signal for each listener of the same speaker if necessary are added, final speaker driving signal is generated.
[0214]
　More specifically, for example, among the speakers constituting the speaker array 25, one for the selected speaker as driving speakers of the listener only the speaker driving signal obtained for the speaker as the final speaker driving signals It is.
[0215]
　In contrast, among the speakers constituting the speaker array 25, for the selected speaker as driving speakers of the plurality of listeners, sum the final speaker of the speaker driving signal obtained for each listener for the speaker It is the drive signal. Further, for the speaker that is not selected as the driving speaker, the speaker drive signal of the speaker, for example, may be a silent signal may be speaker drive signal itself is not generated.
[0216]
　Acoustic filter unit 24, when generating a loudspeaker drive signal for respective speakers of the speaker array 25, and supplies the loudspeaker drive signal obtained speaker array 25.
[0217]
　In step S15, the speaker array 25, and outputs the sound to form a desired sound field on the basis of the speaker drive signal supplied from the acoustic filter unit 24, sound field processing ends.
[0218]
　Above sound field forming device 11 as acquires the listener position information to select the driving speaker and a listener position information forming method information. Also, the sound field forming apparatus 11 performs the convolution processing using only the filter coefficients of the selected drive speaker, to produce a loudspeaker drive signal.
[0219]
　In this way, from among the speakers of the speaker array 25, it is possible to perform sound field to select the appropriate speaker for each listener, suppress interference of the sound to be reproduced for each listener , it is possible to improve the reproducibility of the wave front of the sound. Further, since it is only necessary to perform the convolution operation for driving the speaker for each listener, it is possible to improve the reproducibility of the wavefront with a smaller amount of calculation.
[0220]
　In the case of forming a point source at the position of the listener in the sound field forming apparatus 11, when the listener is moved to another position with time, based on the listener position information that changes in real time, the movement of a listener follow-up is not it is possible to move the position of the point sound source. For example the movement of the point sound source, by moving the position of the speaker to be selected as the driving speaker in accordance with the movement of the listener, that is realized by re-selecting the drive speaker based on the listener position after movement be able to.
[0221]
　Further, an example has been described in which the choice of driving the speaker is performed for each listener in the above, in a case where a plurality of listeners is near to a plurality of listeners and one group performs processing on a group basis it may be so. In such a case, or driving a speaker is selected for each group, the convolution of the source signal and filter coefficients or performed.
[0222]
　In the grouping of the listener, for example, to a predetermined multiple of a listener distance from each other closer than a predetermined distance may be treated as one group, be grouped with the listener by other methods good.
[0223]
　For example, when sound field, the size of the group consisting of a plurality listener, i.e. according to the size of the region containing the listener belonging to the group, the directivity of the sound to be output to the region of that group from the speaker array 25 it may generate a speaker drive signal to widen. That is, for example, may be to change the x-direction and y-direction of the width of the region where the sound is heard by the directivity control.
[0224]
　Further, for example, for a group including a plurality of listeners, if the new listener from outside the group has reached has moved, it may be treated the listener in addition to the group as a new group. Conversely, from the group already exists, when the listener who were in the group went away moving, it may be processed with the exception of the listener as a new group.
[0225]
　Furthermore, for example, the sound field forming apparatus 11, the listener nationality, ie can also be applied to a system for reproducing by switching the content in accordance with the language. In such a case, for example, by utilizing the nationality information of a listener who is listening area, it is sufficient to switch the content to listen to the listener. At this time, nationality information of the listener, for example to the listener may be acquired from an electronic passport in possession, may be obtained by other methods.
[0226]

　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.
[0227]
　Figure 10 is a block diagram showing a configuration example of hardware of a computer that executes the series of processes described above.
[0228]
　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.
[0229]
　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.
[0230]
　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.
[0231]
　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.
[0232]
　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.
[0233]
　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.
[0234]
　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.
[0235]
　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.
[0236]
　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.
[0237]
　Further, each step described in the above flowcharts may be executed by one device, it can be performed by allocating a plurality of apparatuses.
[0238]
　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.
[0239]
　The effects described herein are not intended to be limited to a merely illustrative, there may be other effects.
[0240]
　Additionally, the present technology may also be configured as follows.
[0241]
(1)
　and the listener position acquisition unit that acquires listener position information indicating the position of the listener,
　based on the listener position information, one or more used in the formation of the sound field of the loudspeaker constituting a speaker array and driving the speaker selection section for selecting a speaker as driving speakers,
　and in response to said driving speaker selection result, wherein the driving speaker is driven to generate a speaker drive signal for forming the sound field drive signal generator
　sound field forming apparatus comprising a.
(2)
　the loudspeaker drive signal is a signal for forming the sound field by the wave field synthesis
　sound field forming apparatus according to (1).
(3)
　the driving signal generation unit for the drive speaker of the speakers constituting the speaker array only generates the loudspeaker drive signal by convoluting the filter coefficients and the excitation signal
　(1) or (2) sound field forming apparatus according to.
(4)
　further comprising a filter coefficient recording unit for recording the filter coefficient for each speaker of the speaker array
　sound field forming apparatus according to (3).
(5)
　the driving speaker selection section, said in the speaker array in a direction parallel, to select a speaker located in the vicinity of the listener, as the driving speaker
　sounds according to any one of (1) to (4) If forming apparatus.
(6)
　the driving speaker selection section, in the speaker array in a direction parallel, to select a speaker located in the sound source near generated by formation of the sound field as the driving speaker
　either (1) to (5) sound field forming apparatus according to an item or.
(7)
　the driving speaker selection section, said in the speaker array and the vertical direction, and the listener is such that the number of the driving speaker The more distant position increases from the speaker array, selecting the driving speaker
　( 1) to the sound field forming apparatus according to any one of (6).
(8)
　the driving speaker selection section, when selecting the drive speaker for each of the listener or listener group, as the listener or listener group is large, the to be selected for the listener or listeners group as the number of drive loudspeakers is reduced, it selects the driving speaker
　sound field forming apparatus according to any one of (1) to (7).
(9)
　the driving speaker selection unit selects the driving speaker in accordance with the forming method of the sound field
　sound field forming apparatus according to any one of (1) to (8).
(10)
　to get the listener position information indicating the position of the listener,
　based on the listener position information, one or more speakers to be used for formation of the sound field of the loudspeaker constituting a speaker array as a driving speaker selected,
　depending on the selection result of the driving speaker, to produce a loudspeaker drive signal for forming the sound field by driving the driving speaker
　sound field forming method comprising the steps.
(11)
　to get the listener position information indicating the position of the listener,
　based on the listener position information, one or more speakers to be used for formation of the sound field of the loudspeaker constituting a speaker array as a driving speaker selected,
　depending on the selection result of the driving speaker, the drive speaker is driven to generate a speaker drive signal for forming the sound field
　program for executing the processing including a step in the computer.
DESCRIPTION OF SYMBOLS
[0242]
　11 sound field forming apparatus, 21 the listener position acquisition unit, 22 drive the speaker selection section, 23 acoustic filter coefficient recording section, 24 sound filter unit, 25 speaker array

The scope of the claims
[Requested item 1]
　And the listener position acquisition unit that acquires listener position information indicating the position of the listener,
　based on the listener position information, one or more speakers to be used for formation of the sound field of the loudspeaker constituting a speaker array and driving the speaker selection section that selects a driving speakers,
　in accordance with the selection result of the driving speaker, and the driving speaker is driven to generate a speaker drive signal for forming the sound field drive signal generator
　sound comprising If forming apparatus.
[Requested item 2]
　The loudspeaker drive signal, the wave-field synthesis is a signal for forming the sound field
　sound field forming apparatus according to claim 1.
[Requested item 3]
　The drive signal generating unit, said for the driving speaker of the speakers constituting the speaker array only generates the loudspeaker drive signal by convoluting the filter coefficients and the excitation signal
　sound field forming apparatus according to claim 1 .
[Requested item 4]
　Further comprising a filter coefficient recording unit for recording the filter coefficient for each speaker of the speaker array
　sound field forming apparatus according to claim 3.
[Requested item 5]
　The driving speaker selection section, in the speaker array in a direction parallel, to select a speaker located in the vicinity of the listener, as the driving speaker
　sound field forming apparatus according to claim 1.
[Requested item 6]
　The driving speaker selection section, in the speaker array in a direction parallel, to select a speaker located in the sound source near generated by formation of the sound field as the driving speaker
　sound field forming apparatus according to claim 1.
[Requested item 7]
　The driving speaker selection section, in the speaker array perpendicular direction such that said listener increases the number of the driving speaker The more distant position from the speaker array, to select the drive speaker
　to claim 1 sound field forming apparatus according.
[Requested item 8]
　The driving speaker selection section, when selecting the drive speaker for each of the listener or listener group, as the listener or listener group is large, the drive speakers selected for the listener or listeners group so that the number decreases, selecting the driving speaker
　sound field forming apparatus according to claim 1.
[Requested item 9]
　The driving speaker selection unit selects the driving speaker in accordance with the forming method of the sound field
　sound field forming apparatus according to claim 1.
[Requested item 10]
　Get the listener position information indicating the position of the listener,
　based on the listener position information, one or more speakers to be used for formation of the sound field of the loudspeaker constituting a speaker array is selected as the driving speaker,
　depending on the selection result of the driving speaker, to produce a loudspeaker drive signal for forming the sound field by driving the driving speaker
　sound field forming method comprising the steps.
[Requested item 11]
　Get the listener position information indicating the position of the listener,
　based on the listener position information, one or more speakers to be used for formation of the sound field of the loudspeaker constituting a speaker array is selected as the driving speaker,
　depending on the selection result of the driving speaker, the drive speaker is driven to generate a speaker drive signal for forming the sound field
　program for executing the processing including a step in the computer.