Acoustic reproduction method, computer program, and sound reproduction device

Abstract

To provide an acoustic reproduction method capable of improving a sensation level of a sound reached to a rear side of a listener.SOLUTION: An acoustic reproduction method contains: a signal acquisition step of acquiring a first audio signal that indicates a first sound as a sound reached to a listener from a first range as a range of a predetermined angle and a second audio signal that indicates a second sound as a sound reached to the listener from a predetermined direction; an information acquisition step of acquiring direction information as information of a direction where a head part of the listener is directed; and a correction processing step of executing a correction processing to at least one part of the first and second audio signals that are acquired in the case where it is determined that at least one part of the first range and the predetermined direction is contained in a second range defined on the basis of the direction information to be acquired.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a sound reproduction method and the like. [Background technology]

[0002] Patent Document 1 proposes a technique relating to a stereophonic sound reproduction system that realizes realistic sound by outputting sound from a plurality of speakers arranged around a listener. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-287002 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, a human (here, a listener who hears sound) perceives a lower level of sounds that reach him / her from behind than sounds that reach him / her from in front of him / her among sounds that reach him / her from the surroundings.

[0005] Therefore, an object of the present disclosure is to provide a sound reproduction method and the like that improves the perceived level of sounds reaching a listener from behind. [Means for solving the problem]

[0006] An audio reproduction method according to one embodiment of the present disclosure includes a signal acquisition step of acquiring a first audio signal indicating a first sound, which is a sound reaching a listener from a first range, which is a predetermined angle range, and a second audio signal indicating a second sound, which is a sound reaching the listener from a predetermined direction; an information acquisition step of acquiring directional information, which is information about a direction in which the head of the listener is facing; and a correction processing step of applying a correction process to at least one of the acquired first audio signal and the acquired second audio signal when it is determined based on the acquired directional information that at least a portion of the first range and the predetermined direction are included in a second range determined based on the directional information.

[0007] A program according to an aspect of the present disclosure causes a computer to execute the above-described sound reproducing method.

[0008] An audio reproduction device according to one embodiment of the present disclosure includes a signal acquisition unit that acquires a first audio signal indicating a first sound, which is a sound that reaches a listener from a first range, which is a predetermined angle range, and a second audio signal indicating a second sound, which is a sound that reaches the listener from a predetermined direction; an information acquisition unit that acquires directional information, which is information about a direction in which the head of the listener is facing; and a correction processing unit that applies correction processing to at least one of the acquired first audio signal and the acquired second audio signal when it is determined, based on the acquired directional information, that at least a portion of the first range and the predetermined direction are included in a second range determined based on the directional information.

[0009] In addition, these comprehensive or specific aspects may be realized by a system, an apparatus, a method, an integrated circuit, a computer program, or a non-transitory recording medium such as a computer-readable CD-ROM, or may be realized by any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium. Effect of the Invention

[0010] An audio reproduction method according to an embodiment of the present disclosure can improve the perceived level of sounds arriving from behind a listener. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a block diagram showing a functional configuration of the sound reproducing device according to the first embodiment. [Diagram 2] FIG. 2 is a schematic diagram showing an example of use of sounds output from a plurality of speakers according to the first embodiment. [Diagram 3] FIG. 3 is a flowchart of an operation example of the sound reproducing device according to the first embodiment. [Figure 4] FIG. 4 is a schematic diagram for explaining an example of a determination made by the correction processing unit according to the first embodiment. [Diagram 5] FIG. 5 is a schematic diagram for explaining another example of the determination made by the correction processing unit according to the first embodiment. [Figure 6] FIG. 6 is a schematic diagram for explaining another example of the determination performed by the correction processing unit according to the first embodiment. [Figure 7] FIG. 7 is a diagram illustrating an example of the correction process performed by the correction processor according to the first embodiment. [Figure 8] FIG. 8 is a diagram illustrating another example of the correction process performed by the correction processor according to the first embodiment. [Figure 9] FIG. 9 is a diagram illustrating another example of the correction process performed by the correction processor according to the first embodiment. [Figure 10] FIG. 10 is a schematic diagram showing an example of the correction process performed on the first audio signal according to the first embodiment. [Figure 11] FIG. 11 is a schematic diagram showing another example of the correction process performed on the first audio signal according to the first embodiment. [Figure 12] FIG. 12 is a block diagram showing functional configurations of the sound reproducing device and the sound acquiring device according to the second embodiment. [Figure 13] FIG. 13 is a schematic diagram illustrating sound collection by the sound collection device according to the second embodiment. [Figure 14] FIG. 14 is a schematic diagram showing an example of correction processing performed on a plurality of first audio signals according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] (Findings on which this disclosure is based) 2. Description of the Related Art Conventionally, there is known technology relating to sound reproduction that realizes realistic sound by outputting sounds represented by a plurality of different audio signals from a plurality of speakers arranged around a listener.

[0013] For example, the stereophonic sound reproduction system disclosed in Patent Document 1 includes main speakers, surround speakers, and a stereophonic sound reproduction device.

[0014] The main speaker amplifies the sound indicated by the main audio signal at a position where the listener is located within the directional angle, and the surround speaker amplifies the sound indicated by the surround audio signal toward the walls of the sound field space, and the stereophonic sound reproduction device amplifies each speaker.

[0015] The stereophonic sound reproducing device also has a signal adjusting means, a delay time adding means, and an output means. The signal adjusting means adjusts the frequency characteristics of the surround audio signal based on the propagation environment during sound amplification. The delay time adding means adds a delay time corresponding to the surround signal to the main audio signal. The output means outputs the main audio signal with the delay time added to the main speaker, and the adjusted surround audio signal to the surround speaker.

[0016] Such a stereophonic sound reproduction system makes it possible to create a sound field that provides a high level of realism.

[0017] Incidentally, humans (here, listeners who hear sound) have a lower perception level for sounds that reach them from behind than for sounds that reach them from the front among sounds that reach them from the surroundings. For example, humans have a perception characteristic (more specifically, hearing characteristic) that makes it difficult to perceive the position or direction of a sound that reaches them from behind. This perception characteristic is a characteristic derived from the shape of the human pinna and its discrimination limit.

[0018] In addition, when two kinds of sounds (e.g., a target sound and an environmental sound) arrive from behind the listener, one sound (e.g., the target sound) may be buried in the other sound (e.g., the environmental sound). In this case, the listener has difficulty hearing the target sound, and therefore has difficulty perceiving the position or direction of the target sound arriving from behind the listener.

[0019] For example, even in the stereophonic sound reproduction system disclosed in Patent Document 1, when sounds represented by the main audio signal and sounds represented by the surround audio signal arrive from behind the listener, the listener has difficulty perceiving the sounds represented by the main audio signal. Therefore, there is a demand for an audio reproduction method that improves the perception level of sounds arriving from behind the listener.

[0020] Therefore, an audio reproducing method according to one aspect of the present disclosure includes a signal acquiring step of acquiring a first audio signal indicating a first sound, which is a sound reaching the listener from a first range, which is a predetermined angle range, and a second audio signal indicating a second sound, which is a sound reaching the listener from a predetermined direction; an information acquiring step of acquiring direction information, which is information about a direction in which the head of the listener is facing; a correction processing step of performing a correction process on at least one of the acquired first audio signal and the acquired second audio signal, which is a process in which the intensity of the second audio signal is increased relative to the intensity of the first audio signal, when it is determined that the first range and the predetermined direction are included in the second range based on the acquired direction information, when the direction in which the head of the listener is facing is defined as forward and a range behind the forward direction is defined as a second range; and a mixing processing step of mixing at least one of the first audio signal and the second audio signal that have been subjected to the correction process and outputting the mixed signal to an output channel.

[0021] As a result, when the first range and the predetermined direction are included in the second range, the intensity of the second audio signal indicating the second sound is increased. Therefore, the listener can easily hear the second sound arriving from behind the listener (i.e., behind the listener) when the listener's head is facing in the forward direction. In other words, a sound reproducing method is realized that can improve the perception level of the second sound arriving from behind the listener.

[0022] As an example, when the first sound is an environmental sound and the second sound is a target sound, the target sound can be prevented from being buried in the environmental sound. In other words, a sound reproducing method is realized that can improve the perception level of the target sound arriving from behind the listener.

[0023] For example, the first range is a range behind a reference azimuth defined by the position of the output channel.

[0024] This makes it easier for the listener to hear the second sound arriving from behind the listener, even if the first sound arrives at the listener from a range behind the reference direction.

[0025] For example, the correction process is a process of correcting at least one of a gain of the acquired first audio signal and a gain of the acquired second audio signal.

[0026] This makes it possible to correct the gain of at least one of the first audio signal indicating the first sound and the second audio signal indicating the second sound, making it easier for the listener to hear the second sound arriving from behind the listener.

[0027] For example, the correction process is at least one of a process of decreasing a gain of the acquired first audio signal and a process of increasing a gain of the acquired second audio signal.

[0028] This allows at least one of the processes of decreasing the gain of the first audio signal representing the first sound and increasing the gain of the second audio signal representing the second sound to be performed, making it easier for the listener to hear the second sound arriving from behind the listener.

[0029] For example, the correction process is a process of correcting at least one of a frequency component based on the acquired first audio signal and a frequency component based on the acquired second audio signal.

[0030] This makes it possible to correct at least one of the frequency components based on the first audio signal representing the first sound and the frequency components based on the second audio signal representing the second sound, making it easier for the listener to hear the second sound arriving from behind the listener.

[0031] For example, the correction process is a process of reducing the spectrum of frequency components based on the acquired first audio signal so as to be smaller than the spectrum of frequency components based on the acquired second audio signal.

[0032] This reduces the intensity in the spectrum of the frequency components based on the first audio signal representing the first sound, making it easier for the listener to hear the second sound arriving from behind the listener.

[0033] For example, the correction processing step performs the correction processing based on a positional relationship between the second range and the specified orientation, and the correction processing is a process of correcting at least one of a gain of the acquired first audio signal and a gain of the acquired second audio signal, or a process of correcting at least one of a frequency characteristic based on the acquired first audio signal and a frequency characteristic based on the acquired second audio signal.

[0034] This allows correction processing to be performed based on the positional relationship between the second range and the predetermined direction, making it easier for the listener to hear the second sound arriving from behind the listener.

[0035] For example, when the second range is divided into a right rear range that is a range behind the right of the listener, a left rear range that is a range behind the left of the listener, and a central rear range that is a range between the right rear range and the left rear range, the correction processing step performs the correction processing of decreasing the gain of the acquired first audio signal or increasing the gain of the acquired second audio signal when it is determined that the specified orientation is included in the right rear range or the left rear range, and performs the correction processing of decreasing the gain of the acquired first audio signal and increasing the gain of the acquired second audio signal when it is determined that the specified orientation is included in the central rear range.

[0036] As a result, when the predetermined direction is included in the central rear range, a correction process is performed such that the intensity of the second audio signal representing the second sound is stronger than the intensity of the first audio signal representing the first sound when the predetermined direction is included in the right rear range or the left rear range, making it easier for the listener to hear the second sound arriving from behind the listener.

[0037] For example, the signal acquisition step acquires a plurality of the first audio signals and the second audio signals indicating a plurality of the first sounds, and classification information which is information into which the plurality of first audio signals are classified based on frequency characteristics of each of the plurality of first audio signals, and the correction processing step performs the correction processing based on the acquired direction information and classification information, and each of the plurality of first sounds is a sound picked up from each of a plurality of the first ranges.

[0038] This allows the correction processing step to perform the correction processing for each group into which the multiple first audio signals are classified, thereby reducing the processing load of the correction processing step.

[0039] For example, a sound reproducing method according to one aspect of the present disclosure includes a signal acquiring step of acquiring a plurality of first audio signals indicating a plurality of first sounds, which are a plurality of sounds reaching a listener from a plurality of first ranges, which are ranges of a plurality of predetermined angles, and a second audio signal indicating a second sound, which is a sound reaching the listener from a predetermined direction; an information acquiring step of acquiring direction information, which is information on a direction in which a head of the listener is facing; a correction processing step of performing a correction process on at least one of the acquired plurality of first audio signals and the acquired second audio signals, the correction process being a process in which an intensity of the second audio signal is increased relative to an intensity of the plurality of first audio signals, when it is determined that the plurality of first ranges and the predetermined direction are included in a second range based on the acquired direction information, when the direction in which the head of the listener is facing is defined as forward and a range behind the forward direction is defined as a second range, and

[0040] As a result, when the first range and the predetermined direction are included in the second range, the intensity of the second audio signal indicating the second sound is increased. Therefore, the listener can easily hear the second sound arriving from behind the listener (i.e., behind the listener) when the listener's head is facing in the forward direction. In other words, a sound reproducing method is realized that can improve the perception level of the second sound arriving from behind the listener.

[0041] Furthermore, in the correction processing step, the correction processing can be performed for each group into which the plurality of first audio signals are classified, thereby reducing the processing load of the correction processing step.

[0042] For example, a program according to one aspect of the present disclosure may be a program for causing a computer to execute the above-described sound reproducing method.

[0043] This enables the computer to execute the above-described sound reproducing method in accordance with the program.

[0044] For example, an audio reproduction device according to one aspect of the present disclosure includes a signal acquisition unit that acquires a first audio signal indicating a first sound, which is a sound reaching the listener from a first range, which is a predetermined angle range, and a second audio signal indicating a second sound, which is a sound reaching the listener from a predetermined direction; an information acquisition unit that acquires direction information that is information about a direction in which the head of the listener is facing; a correction processing unit that performs a correction process on at least one of the acquired first audio signal and the acquired second audio signal, the correction process being a process in which an intensity of the second audio signal is increased relative to an intensity of the first audio signal, when it is determined that the first range and the predetermined direction are included in the second range based on the acquired direction information when the direction in which the head of the listener is facing is defined as forward and a range behind the forward direction is defined as a second range; and a mixing processing unit that mixes at least one of the first audio signal and the second audio signal that have been subjected to the correction process and outputs the result to an output channel.

[0045] As a result, when the first range and the predetermined direction are included in the second range, the intensity of the second audio signal indicating the second sound is increased. Therefore, the listener can easily hear the second sound arriving from behind the listener (i.e., behind the listener) when the listener's head is facing in the forward direction. In other words, a sound reproducing device is realized that can improve the perception level of the second sound arriving from behind the listener.

[0046] For example, when the first sound is an environmental sound and the second sound is a target sound, the target sound can be prevented from being buried in the environmental sound. In other words, a sound reproducing device that can improve the perception level of the target sound arriving from behind the listener is realized.

[0047] Furthermore, these comprehensive or specific aspects may be realized in a system, an apparatus, a method, an integrated circuit, a computer program, or a non-transitory recording medium such as a computer-readable CD-ROM, or may be realized in any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0048] Hereinafter, the embodiment will be specifically described with reference to the drawings.

[0049] The embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, the arrangement and connection of the components, steps, and the order of steps shown in the following embodiments are merely examples and are not intended to limit the scope of the claims.

[0050] In the following description, ordinal numbers such as first, second, and third may be attached to elements. These ordinal numbers are attached to elements in order to identify the elements and do not necessarily correspond to a meaningful order. These ordinal numbers may be rearranged, newly added, or removed as appropriate.

[0051] In addition, each figure is a schematic diagram and is not necessarily precisely illustrated. Therefore, the scales and the like are not necessarily the same in each figure. In each figure, the same reference numerals are given to substantially the same configurations, and duplicated explanations are omitted or simplified.

[0052] (Embodiment 1) [composition] First, a configuration of the sound reproducing device 100 according to the embodiment 1 will be described. Fig. 1 is a block diagram showing a functional configuration of the sound reproducing device 100 according to the present embodiment. Fig. 2 is a schematic diagram showing an example of use of sounds output from a plurality of speakers 1, 2, 3, 4, and 5 according to the present embodiment.

[0053] The sound reproducing device 100 according to this embodiment is a device that processes a plurality of acquired audio signals and outputs the processed signals to a plurality of speakers 1, 2, 3, 4, and 5 shown in Fig. 1 and Fig. 2, thereby allowing a listener L to hear sounds represented by the plurality of audio signals. More specifically, the sound reproducing device 100 is a stereophonic sound reproducing device that allows the listener L to hear stereophonic sound.

[0054] Furthermore, the sound reproducing device 100 processes the acquired audio signals based on the orientation information output by the head sensor 300. The orientation information is information on the orientation in which the head of the listener L faces. The orientation in which the head of the listener L faces is also the orientation in which the face of the listener L faces. Note that the orientation means, for example, a direction.

[0055] The head sensor 300 is a device that senses the direction in which the head of the listener L is facing. The head sensor 300 may be a device that senses information on 6 DOF (Degrees Of Freedom) of the head of the listener L. For example, the head sensor 300 is a device that is worn on the head of the listener L, and may be an inertial measurement unit (IMU), an accelerometer, a gyroscope, a magnetic sensor, or a combination of these.

[0056] As shown in Fig. 2, in this embodiment, a plurality of (here, five) speakers 1, 2, 3, 4, and 5 are arranged to surround the listener L. In Fig. 2, in order to explain the directions, 0 o'clock, 3 o'clock, 6 o'clock, and 9 o'clock are shown corresponding to the times indicated on the clock face. Also, the outline arrow indicates the direction in which the head of the listener L faces, and the direction in which the head of the listener L, who is located at the center (also called the origin) of the clock face, faces is the 0 o'clock direction. Hereinafter, the direction connecting the listener L and 0 o'clock may be referred to as the "0 o'clock direction", and the same applies to the other times indicated on the clock face.

[0057] In this embodiment, the five speakers 1, 2, 3, 4, and 5 are configured as a center speaker, a front right speaker, a rear right speaker, a rear left speaker, and a front left speaker. Speaker 1, which is the center speaker, is placed at the 0 o'clock direction here.

[0058] Each of the five speakers 1, 2, 3, 4, and 5 is a loudspeaker that outputs sounds represented by a plurality of audio signals output from the sound reproducing device 100.

[0059] As shown in FIG. 1, the audio playback device 100 includes a first signal processing unit 110, a first decoding unit 121, a second decoding unit 122, a first correction processing unit 131, a second correction processing unit 132, an information acquisition unit 140, and a mixing processing unit 150.

[0060] The first signal processing unit 110 is a processing unit that acquires a plurality of audio signals. The first signal processing unit 110 may acquire the plurality of audio signals by receiving a plurality of audio signals transmitted by other components not shown in Fig. 2, or may acquire a plurality of audio signals stored in a storage device not shown in Fig. 2. The plurality of audio signals acquired by the first signal processing unit 110 are signals including a first audio signal and a second audio signal.

[0061] Here, the first audio signal and the second audio signal will be described.

[0062] The first audio signal is a signal indicating a first sound that is a sound that reaches the listener L from a first range D1 that is a range of a predetermined angle. For example, the first range D1 is a range behind a reference direction determined by the positions of five speakers 1, 2, 3, 4, and 5 that are output channels. In this embodiment, the reference direction is a direction from the listener L toward the speaker 1 that is the center speaker, and is, for example, the 0 o'clock direction, but is not limited to this. The direction behind the 0 o'clock direction that is the reference direction is the 6 o'clock direction, and the first range D1 may include the 6 o'clock direction that is behind the reference direction. In addition, the first range D1 is a range from the 3 o'clock direction to the 9 o'clock direction (that is, a range of 180° in terms of angle), but is not limited to this. Since the reference direction is constant regardless of the direction in which the head of the listener L is facing, the first range D1 is also constant regardless of the direction in which the head of the listener L is facing.

[0063] The first sound is a sound that reaches the listener L from all or a part of the first range D1 having such a spread, and is so-called environmental sound or noise. The first sound may also be called an ambient sound. In this embodiment, the first sound is an environmental sound that reaches the listener L from all areas of the first range D1. Here, the first sound is a sound that reaches the listener L from the entire area indicated by dots in FIG. 2.

[0064] The second audio signal is a signal indicative of a second sound that reaches the listener L from a predetermined direction.

[0065] The second sound is, for example, a sound whose sound image is localized at a black dot shown in Fig. 2. The second sound may be a sound that reaches the listener L from a narrower range than the first sound. The second sound is, for example, a so-called target sound, which is a sound that is mainly heard by the listener L. The target sound can also be said to be a sound other than an environmental sound.

[0066] 2, in this embodiment, the predetermined direction is the 5 o'clock direction, and an arrow indicates that the second sound reaches the listener L from the predetermined direction. The predetermined direction is constant regardless of the direction in which the head of the listener L faces.

[0067] The first signal processing unit 110 will be described again.

[0068] Furthermore, the first signal processing unit 110 performs a process of separating the multiple audio signals into a first audio signal and a second audio signal. The first signal processing unit 110 outputs the separated first audio signal to the first decoding unit 121 and the separated second audio signal to the second decoding unit 122. In the present embodiment, the first signal processing unit 110 is a demultiplexer as an example, but is not limited to this.

[0069] In this embodiment, the multiple audio signals acquired by the first signal processing unit 110 may be subjected to encoding processing such as MPEG-H 3D Audio (ISO / IEC 23008-3) (hereinafter referred to as MPEG-H 3D Audio). That is, the first signal processing unit 110 acquires multiple audio signals that are encoded bit streams.

[0070] The first decoding unit 121 and the second decoding unit 122, which are examples of a signal acquisition unit, acquire a plurality of audio signals. Specifically, the first decoding unit 121 acquires and decodes the first audio signal separated by the first signal processing unit 110. The second decoding unit 122 acquires and decodes the second audio signal separated by the first signal processing unit 110. The first decoding unit 121 and the second decoding unit 122 perform decoding processing based on the above-mentioned MPEG-H 3D Audio, etc.

[0071] The first decoding unit 121 outputs the decoded first audio signal to a first correction processing unit 131 , and the second decoding unit 122 outputs the decoded second audio signal to a second correction processing unit 132 .

[0072] Furthermore, the first decoding unit 121 outputs first information indicating a first range D1 included in the first audio signal to the information acquiring unit 140. The second decoding unit 122 outputs second information indicating a predetermined direction in which a second sound included in the second audio signal reaches the listener L to the information acquiring unit 140.

[0073] The information acquisition unit 140 is a processing unit that acquires the orientation information output from the head sensor 300. Furthermore, the information acquisition unit 140 acquires the first information output by the first decoding unit 121 and the second information output by the second decoding unit 122. The information acquisition unit 140 outputs the acquired orientation information, first information, and second information to the first correction processing unit 131 and the second correction processing unit 132.

[0074] The first correction processing unit 131 and the second correction processing unit 132 are examples of a correction processing unit. The correction processing unit is a processing unit that performs correction processing on at least one of the first audio signal and the second audio signal.

[0075] The first correction processing unit 131 acquires the first audio signal acquired by the first decoding unit 121, and the direction information, the first information, and the second information acquired by the information acquisition unit 140. The second correction processing unit 132 acquires the second audio signal acquired by the second decoding unit 122, and the direction information, the first information, and the second information acquired by the information acquisition unit 140.

[0076] The correction processing units (first correction processing unit 131 and second correction processing unit 132) perform correction processing on at least one of the first audio signal and the second audio signal based on the acquired direction information when predetermined conditions (described later in FIGS. 3 to 6) are met. More specifically, the first correction processing unit 131 performs correction processing on the first audio signal, and the second correction processing unit 132 performs correction processing on the second audio signal.

[0077] Here, when correction processing has been applied to the first audio signal and the second audio signal, the first correction processing unit 131 outputs the first audio signal that has been subjected to the correction processing, and the second correction processing unit 132 outputs the second audio signal that has been subjected to the correction processing, to the mixing processing unit 150.

[0078] In addition, when correction processing has been applied to the first audio signal, the first correction processing unit 131 outputs the first audio signal that has been subjected to the correction processing, and the second correction processing unit 132 outputs the second audio signal that has not been subjected to the correction processing, to the mixing processing unit 150.

[0079] In addition, when correction processing has been applied to the second audio signal, the first correction processing unit 131 outputs the first audio signal that has not been subjected to correction processing, and the second correction processing unit 132 outputs the second audio signal that has been subjected to correction processing, to the mixing processing unit 150.

[0080] The mixing processor 150 is a processor that mixes at least one of the first audio signal and the second audio signal that have been subjected to the correction processing by the correction processor, and outputs the mixed signal to a plurality of speakers 1, 2, 3, 4, and 5 that are output channels.

[0081] More specifically, when the first audio signal and the second audio signal have been subjected to correction processing, the mixing processing unit 150 mixes and outputs the first and second audio signals that have been subjected to correction processing. When the first audio signal has been subjected to correction processing, the mixing processing unit 150 mixes and outputs the first audio signal that has been subjected to correction processing and the second audio signal that has not been subjected to correction processing. When the second audio signal has been subjected to correction processing, the mixing processing unit 150 mixes and outputs the first audio signal that has not been subjected to correction processing and the second audio signal that has been subjected to correction processing.

[0082] As another example, when headphones placed near the auricles of the listener L are used as output channels instead of the multiple speakers 1, 2, 3, 4, and 5 placed around the listener L, the mixing processor 150 performs the following process. In this case, when mixing the first audio signal and the second audio signal, the mixing processor 150 performs a process of convolving a head-related transfer function and outputs the result.

[0083] [Example] The following describes an example of the operation of the sound reproducing method performed by the sound reproducing device 100. Fig. 3 is a flowchart of an example of the operation of the sound reproducing device 100 according to this embodiment.

[0084] The first signal processing unit 110 acquires a plurality of audio signals (S10).

[0085] The first signal processing unit 110 separates the multiple audio signals acquired by the first signal processing unit 110 into a first audio signal and a second audio signal (S20).

[0086] The first decoding unit 121 and the second decoding unit 122 respectively acquire the separated first audio signal and second audio signal (S30). Step S30 is a signal acquisition step. More specifically, the first decoding unit 121 acquires the first audio signal, and the second decoding unit 122 acquires the second audio signal. Furthermore, the first decoding unit 121 decodes the first audio signal, and the second decoding unit 122 decodes the second audio signal.

[0087] Here, the information acquiring unit 140 acquires direction information output by the head sensor 300 (S40). Step S40 is an information acquiring step. The information acquiring unit 140 also acquires first information indicating a first range D1 included in a first audio signal indicating a first sound, and second information indicating a predetermined direction in which a second sound will reach the listener L.

[0088] Furthermore, the information acquisition unit 140 outputs the acquired directional information, first information, and second information to the first correction processing unit 131 and the second correction processing unit 132 (that is, the correction processing units).

[0089] The correction processing unit acquires the first audio signal, the second audio signal, the direction information, the first information, and the second information. Furthermore, the correction processing unit determines whether the first range D1 and the predetermined direction are included in the second range D2 based on the direction information (S50). More specifically, the correction processing unit makes the above determination based on the acquired direction information, the first information, and the second information.

[0090] Here, the determination made by the correction processing section and the second range D2 will be described with reference to FIGS.

[0091] Fig. 4 to Fig. 6 are schematic diagrams for explaining an example of a judgment made by the correction processing unit according to the present embodiment. More specifically, in Fig. 4 and Fig. 5, the correction processing unit judges that the first range D1 and the predetermined direction are included in the second range D2, and in Fig. 6, the correction processing unit judges that the first range D1 and the predetermined direction are not included in the second range D2. Also, Fig. 4, Fig. 5, and Fig. 6 show how the direction in which the head of the listener L is facing changes clockwise in the order of Fig. 4, Fig. 5, and Fig. 6.

[0092] As shown in Figs. 4 to 6, the second range D2 is a range behind the listener L when the direction in which the head of the listener L faces is the forward direction. In other words, the second range D2 is a range behind the listener L. The second range D2 is a range centered on the direction directly opposite the direction in which the head of the listener L faces. As an example, as shown in Fig. 4, when the direction in which the head of the listener L faces is the 0 o'clock direction, the second range D2 is a range from the 4 o'clock direction to the 8 o'clock direction (that is, a range of 120° in terms of angle) centered on the 6 o'clock direction, which is the direction directly opposite the 0 o'clock direction. However, the second range D2 is not limited to this. The second range D2 is determined based on the direction information acquired by the information acquisition unit 140. As shown in FIGS. 4 to 6, when the direction in which the head of the listener L faces changes, the second range D2 changes accordingly, but the first range D1 and the predetermined direction do not change as described above.

[0093] That is, the correction processing unit determines whether or not the first range D1 and the predetermined direction are included in the second range D2, which is a range behind the listener L and is determined based on the direction information. A specific positional relationship between the first range D1, the predetermined direction, and the second range D2 will be described below.

[0094] First, as shown in FIG. 4 and FIG. 5, a case where the correction processing unit determines that both the first range D1 and the predetermined direction are included in the second range D2 (Yes in step S50) will be described.

[0095] When the direction in which the head of the listener L faces is the 0 o'clock direction as shown in FIG. 4, the second range D2 is a range from the 4 o'clock direction to the 8 o'clock direction. The first range D1 related to the first sound, which is the environmental sound, is a range from the 3 o'clock direction to the 9 o'clock direction, and the predetermined direction related to the second sound, which is the target sound, is the 5 o'clock direction. In other words, the predetermined direction is included in a part of the first range D1, and a part of the first range D1 is included in the second range D2. At this time, the correction processing unit determines that both the first range D1 and the predetermined direction are included in the second range D2. Furthermore, the first sound and the second sound are sounds that reach the listener L from the second range D2 (behind the listener L).

[0096] Furthermore, the same is true even if the direction in which the head of the listener L faces as shown in FIG. 5 moves clockwise from the direction shown in FIG.

[0097] 4 and 5, the correction processing unit applies correction processing to at least one of the first audio signal and the second audio signal. Here, as an example, the correction processing unit applies correction processing to both the first audio signal and the second audio signal (S60). More specifically, the first correction processing unit 131 applies correction processing to the first audio signal, and the second correction processing unit 132 applies correction processing to the second audio signal. Step S60 is a correction processing step.

[0098] Furthermore, the correction process performed by the correction processor is a process in which the intensity of the second audio signal is increased relative to the intensity of the first audio signal. "Increasing the intensity of the audio signal" means, for example, that the volume or sound pressure of the sound represented by the audio signal is increased. The correction process will be described in detail in the following first to third examples.

[0099] The first correction processing unit 131 outputs the first audio signal after the correction processing to the mixing processing unit 150, and the second correction processing unit 132 outputs the second audio signal after the correction processing to the mixing processing unit 150.

[0100] The mixing processor 150 mixes the first audio signal and the second audio signal that have been subjected to the correction processing by the correction processor, and outputs the mixed signal to the multiple speakers 1, 2, 3, 4, and 5, which are output channels (S70). Step S70 is a mixing processing step.

[0101] Next, as shown in FIG. 6, a case where the correction processing unit determines that the first range D1 and the predetermined direction are not included in the second range D2 (No in step S50) will be described.

[0102] When the direction in which the head of the listener L faces is the 2 o'clock direction as shown in Fig. 6, the second range D2 is a range from the 6 o'clock direction to the 10 o'clock direction. Moreover, the first range D1 and the predetermined direction do not change from Fig. 4 and Fig. 5. At this time, the correction processing unit determines that the predetermined direction is not included in the second range D2. More specifically, the correction processing unit determines that at least one of the first range D1 and the predetermined direction is not included in the second range D2.

[0103] 6, the correction processing unit does not perform correction processing on the first audio signal and the second audio signal (S80). The first correction processing unit 131 outputs the first audio signal that has not been subjected to correction processing, and the second correction processing unit 132 outputs the second audio signal that has not been subjected to correction processing, to the mixing processing unit 150.

[0104] The mixing processor 150 mixes the first audio signal and the second audio signal that have not been subjected to the correction processing by the correction processor, and outputs the mixed signal to the multiple speakers 1, 2, 3, 4, and 5 that are output channels (S90).

[0105] In this manner, in the present embodiment, when the correction processor determines that the first range D1 and the predetermined direction are included in the second range D2, the correction processor applies correction processing to at least one of the first audio signal and the second audio signal. This correction processing is processing in which the intensity of the second audio signal is increased relative to the intensity of the first audio signal.

[0106] As a result, when the first range D1 and the predetermined direction are included in the second range D2, the intensity of the second audio signal indicating the second sound is increased. Therefore, the listener L can easily hear the second sound reaching the listener L from behind (i.e., behind the listener L) when the direction in which the head of the listener L is facing is assumed to be forward. In other words, the sound reproducing device 100 and the sound reproducing method are realized that can improve the perception level of the second sound reaching the listener L from behind.

[0107] As an example, when the first sound is an environmental sound and the second sound is a target sound, the target sound can be prevented from being buried in the environmental sound. In other words, the sound reproducing device 100 is realized that can improve the perception level of the target sound arriving from behind the listener L.

[0108] The first range D1 is a range behind the reference direction determined by the positions of the five speakers 1, 2, 3, 4 and 5.

[0109] This makes it easier for the listener L to hear the second sound reaching the listener L from behind the listener L, even if the first sound reaches the listener L from a range behind the reference direction.

[0110] Here, first to third examples of the correction process performed by the correction processor will be described.

[0111] <Example 1> In the first example, the correction process is a process of correcting at least one of the gain of the first audio signal acquired by the first decoding unit 121 and the gain of the second audio signal acquired by the second decoding unit 122. More specifically, the correction process is at least one of a process of decreasing the gain of the first audio signal and a process of increasing the gain of the second audio signal.

[0112] Fig. 7 is a diagram for explaining an example of the correction process performed by the correction processing unit according to the present embodiment. More specifically, Fig. 7(a) is a diagram showing the relationship between time and amplitude of the first audio signal and the second audio signal before the correction process is performed. Note that the first range D1 and the multiple speakers 1, 2, 3, 4, and 5 are omitted in Fig. 7, and the same applies to Figs. 8 and 9 described later.

[0113] Fig. 7(b) shows an example in which the correction process is not applied to the first audio signal and the second audio signal. The positional relationship of the first range D1, the predetermined direction, and the second range D2 shown in Fig. 7(b) corresponds to Fig. 6, that is, Fig. 7(b) shows the case of No in step S50 shown in Fig. 3. In this case, the correction processing unit does not apply the correction process to the first audio signal and the second audio signal.

[0114] Fig. 7(c) shows an example in which the first audio signal and the second audio signal are subjected to correction processing. The positional relationship between the first range D1, the predetermined direction, and the second range D2 shown in Fig. 7(c) corresponds to Fig. 4, that is, Fig. 7(c) shows the case where the answer is Yes in step S50 shown in Fig. 3.

[0115] In this case, the correction processing unit performs at least one of a process of decreasing the gain of the first audio signal and a process of increasing the gain of the second audio signal. Here, the correction processing unit performs both a process of decreasing the gain of the first audio signal and a process of increasing the gain of the second audio signal. By correcting the gains of the first audio signal and the second audio signal in this manner, the amplitudes of the first audio signal and the second audio signal are corrected as shown in FIG. 7. In other words, the correction processing unit performs both a process of decreasing the amplitude of the first audio signal representing the first sound and a process of increasing the amplitude of the second audio signal representing the second sound. This makes it easier for the listener L to hear the second sound.

[0116] In the first example, the correction process is a process of correcting the gain of at least one of the first audio signal and the second audio signal, whereby the amplitude of at least one of the first audio signal representing the first sound and the second audio signal representing the second sound is corrected, making it easier for the listener L to hear the second sound.

[0117] More specifically, the correction process is at least one of a process of decreasing a gain of a first audio signal representing the first sound and a process of increasing a gain of a second audio signal representing the second sound, which makes it easier for the listener L to hear the second sound.

[0118] <Second Example> In the second example, the correction process is a process of correcting at least one of the frequency components based on the first audio signal acquired by the first decoding unit 121 and the frequency components based on the second audio signal acquired by the second decoding unit 122. More specifically, the correction process is a process of reducing the spectrum of the frequency components based on the first audio signal so as to be smaller than the spectrum of the frequency components based on the second audio signal. Here, as an example, the correction process is a process of subtracting the spectrum of the frequency components based on the second audio signal from the spectrum of the frequency components based on the first audio signal.

[0119] Fig. 8 is a diagram illustrating another example of the correction process performed by the correction processor according to the present embodiment. More specifically, (a) of Fig. 8 is a diagram illustrating a spectrum of frequency components based on the first audio signal and the second audio signal before the correction process is performed. The spectrum of frequency components is obtained, for example, by performing a Fourier transform process on the first audio signal and the second audio signal.

[0120] Fig. 8(b) shows an example in which the correction process is not applied to the first audio signal and the second audio signal. The positional relationship of the first range D1, the predetermined direction, and the second range D2 shown in Fig. 8(b) corresponds to Fig. 6, that is, Fig. 8(b) shows the case of No in step S50 shown in Fig. 3. In this case, the correction processing unit does not apply the correction process to the first audio signal and the second audio signal.

[0121] Fig. 8(c) shows an example in which the correction process is performed on the first audio signal. The positional relationship between the first range D1, the predetermined direction, and the second range D2 shown in Fig. 8(c) corresponds to Fig. 4, that is, Fig. 8(c) shows the case where the answer is Yes in step S50 shown in Fig. 3.

[0122] In this case, the correction processing unit (more specifically, the first correction processing unit 131) performs processing to subtract the spectrum of frequency components based on the second audio signal from the spectrum of frequency components based on the first audio signal. As a result, as shown in (c) of FIG. 8, the intensity of the spectrum of frequency components based on the first audio signal indicating the first sound decreases. On the other hand, since no correction processing is performed on the second audio signal, the intensity of the spectrum of frequency components based on the second audio indicating the second sound remains constant. In other words, the intensity of a part of the spectrum of frequency components based on the first audio signal decreases, and the intensity of the second audio remains constant. This makes it easier for the listener L to hear the second sound.

[0123] In the second example, the correction process corrects at least one of a frequency component based on a first audio signal representing a first sound and a frequency component based on a second audio signal representing a second sound, thereby making it easier for the listener L to hear the second sound.

[0124] Furthermore, the correction process is a process of reducing the spectrum of frequency components based on the first audio signal so as to be smaller than the spectrum of frequency components based on the second audio signal. Here, the correction process is a process of subtracting the spectrum of frequency components based on the second audio signal from the spectrum of frequency components based on the first audio signal. This reduces the intensity of a portion of the spectrum of frequency components based on the first audio signal that represent the first sound, making it easier for the listener L to hear the second sound.

[0125] The correction process may be a process of reducing the spectrum of frequency components based on the first audio signal by a predetermined ratio compared to the spectrum of frequency components based on the second audio signal. For example, the correction process may be performed so that the peak intensity of the spectrum of frequency components based on the second audio signal becomes equal to or smaller than a predetermined ratio relative to the peak intensity of the spectrum of frequency components based on the first audio signal.

[0126] <Example 3> In the third example, the correction processing unit performs a correction process based on the positional relationship between the second range D2 and a predetermined direction. At this time, the correction process is a process of correcting at least one of the gains of the first audio signal and the second audio signal, or a process of correcting at least one of the frequency characteristics based on the first audio signal and the frequency characteristics based on the second audio signal. Here, the correction process is a process of correcting at least one of the gains of the first audio signal and the second audio signal.

[0127] Fig. 9 is a diagram for explaining another example of the correction process performed by the correction processing unit according to the present embodiment. More specifically, (a) of Fig. 9 is a diagram showing the time and amplitude relationship of the first audio signal and the second audio signal before the correction process is performed. (b) and (c) of Fig. 9 show an example in which at least one of the gains of the first audio signal and the second audio signal is corrected. (c) of Fig. 9 shows an example in which the second sound reaches the listener L from the 7 o'clock direction.

[0128] In the third example, the second range D2 is divided as follows: As shown in (b) and (c) of Fig. 9, the second range D2 is divided into a right rear range D21, which is a range behind the right of the listener L, a left rear range D23, which is a range behind the left of the listener L, and a central rear range D22, which is a range between the right rear range D21 and the left rear range D23. Note that the central rear range D22 preferably includes a direction directly behind the listener L.

[0129] 9(b) shows an example in which the correction processing unit determines that a predetermined direction (here, the 5 o'clock direction) is included in the right rear range D21. At this time, the correction processing unit performs a correction process that is a process of decreasing the gain of the first audio signal or a process of increasing the gain of the second audio signal. Here, the correction processing unit (more specifically, the second correction processing unit 132) performs a correction process that is a process of increasing the gain of the second audio signal.

[0130] This makes it easier for the listener L to hear the second sound.

[0131] Although not shown, a similar correction process is performed in an example in which the correction processing unit determines that the predetermined orientation is included in the left rear range D23.

[0132] 9(c) shows an example in which the correction processing unit determines that a predetermined orientation (here, the 7 o'clock orientation) is included in the central rear range D22. At this time, the correction processing unit performs correction processing to reduce the gain of the first audio signal and to increase the gain of the second audio signal. Here, the first correction processing unit 131 performs correction processing to reduce the gain of the first audio signal, and the second correction processing unit 132 performs correction processing to increase the gain of the second audio signal. As a result, the amplitude of the first audio signal is corrected to decrease and the amplitude of the second audio signal is corrected to increase.

[0133] This makes it easier for the listener L to hear the second sound compared to the example shown in FIG. 9(b).

[0134] As described above, humans have a low perception level of a sound that arrives from behind them. Furthermore, the closer the direction from which the sound arrives to the direction directly behind them, the lower the perception level of the sound.

[0135] Therefore, the correction process shown in the third example is performed. That is, the correction process is performed based on the positional relationship between the second range D2 and the predetermined direction. More specifically, when the predetermined direction is included in the central rear range D22 including the direction directly behind the listener L, the following correction process is performed. At this time, the correction process is performed such that the intensity of the second audio signal representing the second sound becomes stronger relative to the intensity of the first audio signal representing the first sound, compared to when the predetermined direction is included in the right rear range D21, etc. Therefore, the listener L can more easily hear the second sound.

[0136] [Correction process details] Further, details of the correction process performed by the correction processor on the first audio signal representing the first sound will be described with reference to FIGS.

[0137] Fig. 10 is a schematic diagram showing an example of a correction process applied to a first audio signal according to the present embodiment. Fig. 11 is a schematic diagram showing another example of a correction process applied to a first audio signal according to the present embodiment. Note that in Figs. 10 and 11, the direction in which the head of the listener L faces is the 0 o'clock direction, as in Fig. 2 and the like.

[0138] In the above-mentioned first to third examples, the correction processing unit may perform correction processing on the first audio signal indicating a part of the first sound, as will be described below.

[0139] For example, as shown in Fig. 10, the correction processing unit applies correction processing to a first audio signal indicating a part of the first sound that reaches the listener L from the entire range of the second range D2. The part of the first sound that reaches the listener L from the entire range of the second range D2 is a sound that reaches the listener L from the entire area marked with light dots in Fig. 10. Note that the other parts of the first sound are sounds that reach the listener L from the entire area marked with dark dots in Fig. 10.

[0140] In this case, the correction processing unit performs a correction process that reduces the gain of the first audio signal that indicates the first sound that reaches the listener L from the entire range of the second range D2, for example.

[0141] 11, for example, the correction processing unit performs correction processing on a first audio signal indicating a sound, of the first sound, that reaches the listener L from around a predetermined direction in which the second sound reaches the listener L. As an example, the periphery of the predetermined direction is, but is not limited to, a range D11 having an angle of about 30° centered on the predetermined direction, as shown in FIG.

[0142] Moreover, the first sound that reaches the listener L from the periphery of the predetermined direction is the sound that reaches the listener L from the entire region marked with light dots in Fig. 11. Note that the other sounds of the first sound are the sounds that reach the listener L from the entire region marked with dark dots in Fig. 11.

[0143] In this case, the correction processing unit performs a correction process, for example, a process of reducing the gain of a first audio signal indicating a sound that reaches the listener L from around a specified direction in which the second sound of the first sound reaches the listener L.

[0144] In this way, the correction process may be applied to the first audio signal representing a part of the first sound. This eliminates the need to apply the correction process to the entire first audio signal, thereby reducing the processing load of the first correction processor 131 that corrects the first audio signal.

[0145] Note that the same processing may be performed on the first audio signal representing all sounds of the first sound.

[0146] (Embodiment 2) Next, a sound reproducing device 100a according to the second embodiment will be described.

[0147] FIG. 12 is a block diagram showing the functional configuration of the sound reproducing device 100a and the sound acquiring device 200 according to this embodiment.

[0148] In this embodiment, the sound collected by the sound collection device 500 is output from multiple speakers 1, 2, 3, 4, and 5 via the sound acquisition device 200 and the sound reproduction device 100a. More specifically, the sound acquisition device 200 acquires multiple audio signals based on the sound collected by the sound collection device 500 and outputs them to the sound reproduction device 100a. The sound reproduction device 100a acquires the multiple audio signals output by the sound acquisition device 200 and outputs them to the multiple speakers 1, 2, 3, 4, and 5.

[0149] The sound collection device 500 is a device that collects sound that reaches the sound collection device 500, and is, for example, a microphone. The sound collection device 500 may have directionality. Therefore, the sound collection device 500 can collect sound from a specific direction. The sound collection device 500 converts the collected sound using an A / D converter and outputs the converted sound as an audio signal to the sound acquisition device 200. Note that a plurality of sound collection devices 500 may be provided.

[0150] The sound collection device 500 will be described in more detail with reference to FIG.

[0151] FIG. 13 is a schematic diagram illustrating sound collection by the sound collection device 500 according to this embodiment.

[0152] 13, like Fig. 2, 0:00, 3:00, 6:00, and 9:00 are shown corresponding to the times indicated on the clock face in order to explain the directions. Sound collection device 500 is located at the center (also called the origin) of the clock face and collects sounds that reach sound collection device 500. Hereinafter, the direction connecting sound collection device 500 and 0:00 may be referred to as the "0:00 direction," and the same applies to the other times indicated on the clock face.

[0153] The sound collection device 500 collects a plurality of first sounds and a second sound.

[0154] Here, the sound collection device 500 collects four first sounds as the multiple first sounds. For ease of identification, the first sounds are described as a first sound A, a first sound B-1, a first sound B-2, and a first sound B-3, as shown in FIG.

[0155] Since the sound collection device 500 can collect sounds from a specific direction, as an example, the range around the sound collection device 500 is divided into four ranges and sounds are collected for each divided range, as shown in Fig. 13. Here, the range around the sound collection device 500 is divided into four ranges: a range from the 0 o'clock direction to the 3 o'clock direction, a range from the 3 o'clock direction to the 6 o'clock direction, a range from the 6 o'clock direction to the 9 o'clock direction, and a range from the 9 o'clock direction to the 0 o'clock direction.

[0156] In this embodiment, each of the multiple first sounds is a sound that reaches the sound collection device 500 from a first range D1 that is a range of a predetermined angle, that is, a sound that is collected by the sound collection device 500 from each of the multiple first ranges D1. Note that the first range D1 corresponds to one of the four ranges.

[0157] Specifically, as shown in FIG. 13, the first sound A is a sound that reaches the sound collection device 500 from the first range D1, which is a range from the 0 o'clock direction to the 3 o'clock direction. In other words, the first sound A is a sound that is collected from the first range D1. Similarly, the first sound B-1, the first sound B-2, and the first sound B-3 are sounds that reach the sound collection device 500 from the first range D1, which is a range from the 3 o'clock direction to the 6 o'clock direction, from the 6 o'clock direction to the 9 o'clock direction, and from the 9 o'clock direction to the 0 o'clock direction, respectively. In other words, the first sound B-1, the first sound B-2, and the first sound B-3 are each a sound that is collected from each of the three first ranges D1. Note that the first sound B-1, the first sound B-2, and the first sound B-3 may be collectively referred to as the first sound B.

[0158] In addition, here, the first sound A is a sound that reaches the listener L from the entire shaded area in Fig. 13. Similarly, the first sound B-1, the first sound B-2, and the first sound B-3 are sounds that reach the listener L from the entire dotted area in Fig. 13. The same is true in Fig. 14.

[0159] The second sound is a sound that arrives at the sound collection device 500 from a predetermined direction (here, the 5 o'clock direction). The second sound may be collected for each divided range, like the multiple first sounds.

[0160] In addition, the relationship between the sound collected by the sound collection device 500 and the sound output from the multiple speakers 1, 2, 3, 4, and 5 will be described. The multiple speakers 1, 2, 3, 4, and 5 output sounds so as to reproduce the sound collected by the sound collection device 500. That is, in this embodiment, since the listener L and the sound collection device 500 are both placed at the origin, the second sound that reaches the sound collection device 500 from a predetermined direction is heard by the listener L as a sound that reaches the listener L from the predetermined direction. Similarly, the first sound A that reaches the sound collection device 500 from the first range D1 (a range from the 0 o'clock direction to the 3 o'clock direction) is heard by the listener L as a sound that reaches the listener L from the first range D1.

[0161] The sound collection device 500 outputs a plurality of audio signals to the sound acquisition device 200. The plurality of audio signals includes a plurality of first audio signals indicating a plurality of first sounds and a second audio signal indicating a second sound. The plurality of first audio signals also includes a first audio signal indicating a first sound A and a first audio signal indicating a first sound B. More specifically, the first audio signal indicating the first sound B includes three first audio signals indicating the first sound B-1, the first sound B-2, and the first sound B-3, respectively.

[0162] The sound acquiring device 200 acquires a plurality of audio signals output by the sound collecting device 500. At this time, the sound acquiring device 200 may acquire classification information.

[0163] The classification information is information in which the first audio signals are classified based on their respective frequency characteristics, i.e., in the classification information, the first audio signals are classified into different groups for each frequency characteristic based on their respective frequency characteristics.

[0164] In this embodiment, the first sound A and the first sound B are different types of sounds and have different frequency characteristics, so the first audio signal representing the first sound A and the first audio signal representing the first sound B are classified into different groups.

[0165] That is, the first audio signal representing the first sound A is classified into one group, and the three first audio signals representing the first sound B-1, the first sound B-2, and the first sound B-3 are classified into another group.

[0166] Furthermore, instead of the sound acquiring device 200 acquiring the classification information, the sound acquiring device 200 may generate the classification information based on the acquired multiple audio signals. In other words, the classification information may be generated by a processing unit included in the sound acquiring device 200, which is not shown in FIG.

[0167] Next, a description will be given of components included in the sound acquiring device 200. As shown in Fig. 12, the sound acquiring device 200 is a device including an encoding unit (a plurality of first encoding units 221 and a second encoding unit 222) and a second signal processing unit 210.

[0168] The encoding unit (the multiple first encoding units 221 and the second encoding unit 222) acquires the multiple audio signals output by the sound collection device 500 and the classification information. The encoding unit acquires the multiple audio signals and then encodes them. More specifically, the multiple first encoding units 221 acquire and encode the multiple first audio signals, and the second encoding unit 222 acquires and encodes the second audio signal. The multiple first encoding units 221 and the second encoding unit 222 perform encoding processing based on the above-mentioned MPEG-H 3D Audio, etc.

[0169] Here, each of the multiple first encoding units 221 may be in one-to-one correspondence with each of the multiple first audio signals classified into different groups indicated by the classification information. Each of the multiple first encoding units 221 encodes each of the multiple associated first audio signals. For example, the classification information indicates two groups (a group into which the first audio signals indicating the first sound A are classified, and a group into which the first audio signals indicating the first sound B are classified). Therefore, here, two first encoding units 221 are provided, and one of the two first encoding units 221 encodes the first audio signal indicating the first sound A, and the other of the two first encoding units 221 encodes the first audio signal indicating the first sound B. Note that, when the sound acquisition device 200 includes one first encoding unit 221, the one first encoding unit 221 acquires and encodes the multiple first audio signals.

[0170] The encoding unit outputs the encoded first audio signals, the encoded second audio signal, and the classification information to the second signal processing unit 210.

[0171] The second signal processing unit 210 obtains a plurality of encoded first audio signals, a plurality of encoded second audio signals, and classification information. The second signal processing unit 210 combines the plurality of encoded first audio signals and the plurality of encoded second audio signals to obtain a plurality of encoded audio signals. The plurality of encoded audio signals are so-called multiplexed audio signals. Note that, in the present embodiment, the second signal processing unit 210 is a multiplexer as an example, but is not limited thereto.

[0172] The second signal processing unit 210 outputs the multiple audio signals, which are encoded bitstreams, and the classification information to the sound reproducing device 100a (more specifically, to the first signal processing unit 110).

[0173] The following description of the processing performed by the sound reproducing device 100a will focus mainly on the differences from the first embodiment. Note that the sound reproducing device 100a in the present embodiment is different from the first embodiment in that it includes a plurality of first decoding units 121.

[0174] The first signal processing unit 110 acquires the output audio signals and classification information, and performs processing to separate the audio signals into a plurality of first audio signals and a plurality of second audio signals. The first signal processing unit 110 outputs the separated first audio signals and classification information to a plurality of first decoding units 121, and outputs the separated second audio signals and classification information to a second decoding unit 122.

[0175] The first decoding units 121 acquire and decode the first audio signals separated by the first signal processing unit 110.

[0176] Here, each of the multiple first decoding units 121 may be associated one-to-one with each of the multiple first audio signals classified into different groups indicated by the classification information. Each of the multiple first decoding units 121 decodes each of the multiple associated first audio signals. As with the above-mentioned first encoding unit 221, two first decoding units 121 are provided here, and one of the two first decoding units 121 decodes a first audio signal indicating a first sound A, and the other of the two first decoding units 121 decodes a first audio signal indicating a first sound B. Note that, when the sound reproducing device 100a includes one first decoding unit 121, the one first decoding unit 121 acquires and decodes the multiple first audio signals.

[0177] The first decoding units 121 output the decoded first audio signals and the classification information to the first correction processing unit 131. The second decoding unit 122 outputs the decoded second audio signals and the classification information to the second correction processing unit 132.

[0178] Furthermore, the first correction processing unit 131 acquires the multiple first audio signals and classification information acquired by the multiple first decoding units 121, and the direction information, first information, and second information acquired by the information acquisition unit 140.

[0179] Similarly, the second correction processing unit 132 acquires the second audio signal and classification information acquired by the second decoding unit 122, and the direction information, the first information, and the second information acquired by the information acquisition unit 140.

[0180] It should be noted that the first information according to the present embodiment includes information indicating one first range D1 related to the first sound A and three first ranges D1 related to the first sound B contained in the multiple first audio signals.

[0181] Next, the correction process performed by the correction processor will be described with reference to Fig. 14. Fig. 14 is a schematic diagram showing an example of the correction process performed on a plurality of first audio signals according to the present embodiment. Fig. 14(a) shows an example before the correction process is performed, and Fig. 14(b) shows an example after the correction process is performed.

[0182] In this embodiment, the correction processing unit performs the correction process based on the direction information and the classification information. Here, a case will be described in which the correction processing unit determines that one of the multiple first ranges D1 and a predetermined direction are included in the second range D2. In this case, the correction processing unit performs the correction process on at least one of a first audio signal and a second audio signal indicating one first sound reaching the listener L from the one first range D1. More specifically, the correction processing unit performs the correction process on at least one of all the first audio signals and the second audio signals classified into the same group as the one first audio signal based on the classification information.

[0183] 14, for example, the correction processing unit determines that the first range D1 (range from the 3 o'clock direction to the 6 o'clock direction) and a predetermined direction (the 5 o'clock direction) are included in the second range D2 (range from the 4 o'clock direction to the 8 o'clock direction). The sound that reaches the listener L from the first range D1 is the first sound B-1. All the first audio signals classified into the same group as the first audio signal indicating the first sound B-1 are the three first audio signals indicating the first sound B-1, the first sound B-2, and the first sound B-3, respectively.

[0184] In other words, the correction processing unit performs correction processing on at least one of the three first audio signals indicating the first sound B-1, the first sound B-2, and the first sound B-3 (in other words, the first audio signal indicating the first sound B) and the second audio signal.

[0185] This allows the correction processing unit to perform correction processing for each group into which the multiple first audio signals are classified. Here, the correction processing unit can collectively perform correction processing on three first audio signals representing the first sound B-1, the first sound B-2, and the first sound B-3, respectively. This reduces the processing load on the correction processing unit.

[0186] (Other embodiments) Although the sound reproducing device and the sound reproducing method according to the aspects of the present disclosure have been described above based on the embodiment, the present disclosure is not limited to this embodiment. For example, the present disclosure may be realized by combining the components described in this specification in any way, or by excluding some of the components. In addition, the present disclosure also includes modifications obtained by applying various modifications that a person skilled in the art can think of to the above-mentioned embodiment without departing from the gist of the present disclosure, that is, the meaning indicated by the words described in the claims.

[0187] The following forms may also be included within the scope of one or more aspects of the present disclosure.

[0188] (1) Some of the components constituting the above-mentioned sound reproducing device may be a computer system composed of a microprocessor, ROM, RAM, a hard disk unit, a display unit, a keyboard, a mouse, etc. A computer program is stored in the RAM or hard disk unit. The microprocessor operates according to the computer program to achieve its functions. Here, the computer program is composed of a combination of multiple instruction codes that indicate commands for a computer to achieve a specified function.

[0189] (2) Some of the components constituting the above-mentioned sound reproducing device and sound reproducing method may be composed of one system LSI (Large Scale Integration). The system LSI is an ultra-multifunctional LSI manufactured by integrating multiple components on a single chip, and specifically, is a computer system including a microprocessor, ROM, RAM, etc. A computer program is stored in the RAM. The system LSI achieves its functions by the microprocessor operating in accordance with the computer program.

[0190] (3) Some of the components constituting the above-mentioned sound reproducing device may be composed of an IC card or a standalone module that can be attached to each device. The IC card or the module is a computer system composed of a microprocessor, ROM, RAM, etc. The IC card or the module may include the above-mentioned ultra-multifunction LSI. The microprocessor operates according to a computer program, causing the IC card or the module to achieve its functions. The IC card or the module may be tamper-resistant.

[0191] (4) Furthermore, some of the components constituting the above-mentioned sound reproducing device may be the computer program or the digital signal recorded on a computer-readable recording medium, such as a flexible disk, a hard disk, a CD-ROM, an MO, a DVD, a DVD-ROM, a DVD-RAM, a BD (Blu-ray (registered trademark) Disc), a semiconductor memory, etc. Also, they may be digital signals recorded on these recording media.

[0192] In addition, some of the components constituting the above-mentioned sound reproduction device may transmit the computer program or the digital signal via a telecommunications line, a wireless or wired communication line, a network such as the Internet, data broadcasting, etc.

[0193] (5) The present disclosure may be embodied as any of the methods described above, a computer program for implementing these methods by a computer, or a digital signal comprising the computer program.

[0194] (6) The present disclosure may also provide a computer system having a microprocessor and a memory, the memory storing the computer program, and the microprocessor operating in accordance with the computer program.

[0195] (7) The program or the digital signal may also be implemented by another independent computer system by recording it on the recording medium and transferring it, or by transferring the program or the digital signal via the network, etc.

[0196] (8) The above-described embodiments and modifications may be combined with each other.

[0197] 2 and the like, an image linked to sounds output from the multiple speakers 1, 2, 3, 4, and 5 may be presented to the listener L. In this case, for example, a display device such as a liquid crystal panel or an organic EL (Electro Luminescence) panel may be provided around the listener L, and the image is presented on the display device. The image may also be presented to the listener L by wearing a head-mounted display or the like.

[0198] In the above embodiment, as shown in Fig. 2, five speakers 1, 2, 3, 4, and 5 are provided, but the present invention is not limited to this. For example, a 5.1ch surround system provided with the five speakers 1, 2, 3, 4, and 5 and a speaker corresponding to a subwoofer may be used. Also, a multi-channel surround system provided with two speakers may be used, but the present invention is not limited to this. [Industrial Applicability]

[0199] The present disclosure is applicable to sound reproduction devices and sound reproduction methods, and is particularly applicable to stereophonic sound reproduction systems and the like. [Explanation of symbols]

[0200] 1, 2, 3, 4, 5 Speakers 100, 100a Sound reproduction device 110 First signal processing section 121 First Decoding Unit 122 Second Decoding Unit 131 First correction processing unit 132 Second correction processing section 140 Information Acquisition Department 150 Mixing Processing Unit 200 Acoustic Acquisition Device 210 Second signal processing section 221 1st encoding section 222 Second encoding section 300 Head Sensor 500 Sound recording device D1 1st range D2 2nd range D11 Range D21 Right rear range D22 Center Rear Range D23 Left rear range L listener

Claims

1. a signal acquisition step of acquiring a first audio signal indicative of a first sound, which is a sound reaching the listener from a first range, which is a predetermined angular range, and a second audio signal indicative of a second sound, which is a sound reaching the listener from a predetermined direction; an information acquiring step of acquiring direction information which is information on a direction in which the head of the listener is facing; and a correction processing step of performing a correction process on at least one of the acquired first audio signal and the acquired second audio signal when it is determined based on the acquired direction information that at least a part of the first range and the predetermined direction is included in a second range determined based on the direction information. Sound reproduction method.

2. The range indicated by the second range changes in response to changes in the direction in which the listener's head is facing.

2. The sound reproducing method according to claim 1.

3. The range indicated by the second range is a range behind the direction in which the head of the listener is facing, assuming the direction to be forward. The sound reproducing method according to claim 2.

4. The second range is a range centered on a direction directly opposite to the direction in which the head of the listener is facing. The sound reproducing method according to claim 2.

5. The correction processing step performs the correction processing, which is a process of reducing the intensity of the acquired first audio signal. The sound reproducing method according to claim 2.

6. The correction processing step performs the correction processing, which is processing for increasing the intensity of the acquired second audio signal. The sound reproducing method according to claim 2.

7. The correction processing step performs a correction process on at least one of the acquired first audio signal and the acquired second audio signal, the correction process being a process in which an intensity of the second audio signal is increased relative to an intensity of the first audio signal. The sound reproducing method according to claim 2.

8. a mixing step of mixing at least one of the first audio signal and the second audio signal that have been subjected to the correction processing and outputting the mixed signal to an output channel. The sound reproducing method according to claim 2.

9. The first range is a range behind a reference direction determined by the position of the output channel. The sound reproducing method according to claim 8.

10. The correction process is a process of correcting at least one of a gain of the acquired first audio signal and a gain of the acquired second audio signal. The sound reproducing method according to claim 7.

11. The correction process is at least one of a process of decreasing a gain of the acquired first audio signal and a process of increasing a gain of the acquired second audio signal. The sound reproducing method according to claim 7.

12. The correction process is a process of correcting at least one of a frequency component based on the acquired first audio signal and a frequency component based on the acquired second audio signal. The sound reproducing method according to claim 7.

13. The correction process is a process of reducing a spectrum of frequency components based on the acquired first audio signal so as to be smaller than a spectrum of frequency components based on the acquired second audio signal. The sound reproducing method according to claim 7.

14. the correction processing step performs the correction processing based on a positional relationship between the second range and the predetermined direction; The correction process is a process of correcting at least one of a gain of the acquired first audio signal and a gain of the acquired second audio signal, or a process of correcting at least one of a frequency characteristic based on the acquired first audio signal and a frequency characteristic based on the acquired second audio signal. The sound reproducing method according to claim 7.

15. When the second range is divided into a right rear range, a left rear range, and a center rear range between the right rear range and the left rear range of the listener, The correction processing step includes: When it is determined that the predetermined direction is included in the right rear range or the left rear range, the correction process is performed to reduce a gain of the acquired first audio signal or to increase a gain of the acquired second audio signal; When it is determined that the predetermined direction is included in the central rear range, the correction process is performed, which is a process of decreasing a gain of the acquired first audio signal and a process of increasing a gain of the acquired second audio signal.

15. The method for reproducing sound according to claim 14.

16. The signal acquisition step includes: a plurality of the first audio signals and the second audio signals representing a plurality of the first sounds; acquiring classification information indicating classification of the first audio signals based on frequency characteristics of the first audio signals; The correction processing step performs the correction processing based on the acquired direction information and classification information, Each of the plurality of first sounds is a sound collected from each of the plurality of first ranges. The sound reproducing method according to claim 7.

17. A computer program for causing a computer to execute the sound reproducing method according to any one of claims 1 to 16.

18. a signal acquisition unit that acquires a first audio signal indicative of a first sound that is a sound that reaches the listener from a first range that is a predetermined angle range, and a second audio signal indicative of a second sound that is a sound that reaches the listener from a predetermined direction; an information acquisition unit that acquires direction information that is information about a direction in which the head of the listener is facing; a correction processing unit that performs a correction process on at least one of the acquired first audio signal and the acquired second audio signal when it is determined, based on the acquired direction information, that at least a part of the first range and the predetermined direction is included in a second range determined based on the direction information. Sound reproduction device.

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