JP5843705B2 - Audio control device, audio reproduction device, television receiver, audio control method, program, and recording medium - Google Patents

Description

  The present invention relates to an audio control device, an audio reproduction device, a television receiver, an audio control method, a program, and a recording medium that can control audio output from a plurality of speakers.

  Conventionally, in order to obtain a realistic surround effect when viewing video content, an acoustic system (hereinafter referred to as “multi-channel acoustic system”) employing a 5.1 channel multi-channel acoustic system has been used. Yes. In a multi-channel sound system, a multi-channel audio signal including a plurality of channels and having an ideal audio output position corresponding to each channel is used in advance. By outputting the sound represented by the sound signal of each channel constituting the multi-channel sound signal from the speaker arranged at the sound output position corresponding to the channel, the user feels as if they are in the sound field. be able to.

  In particular, in recent years, a 22.2 channel multi-channel sound system has been formulated as a multi-channel sound system scheduled to be used for Super Hi-Vision. This 22.2 channel multi-channel sound system includes three channel layers (upper layer 9 channels, middle layer 10 channels, lower layer 3 channels) in a three-dimensional space, and LFE (Low Frequency Effects). It is configured to include two channels. As a result, a multi-channel sound system employing a 22.2 channel sound system is said to provide a natural and high-quality three-dimensional sound effect.

  In such a multi-channel sound system, in order to obtain a favorable surround effect, it is necessary to arrange a number of speakers corresponding to the number of channels at appropriate positions determined in advance.

  However, in reality, there are many cases where only a smaller number of speakers than the number of channels of the acoustic system can be installed due to restrictions such as installation space and installation cost, or speakers cannot be installed at predetermined positions.

  Therefore, conventionally, with respect to a multi-channel sound system, even when a predetermined number of speakers cannot be arranged at a predetermined appropriate position, it is possible to obtain the best possible surround effect. Various techniques have been devised.

  For example, in Patent Document 1 below, in a sound reproduction device, it is detected whether the position of a speaker is a normal mode or an NFL (near field listening) mode, and in the NFL mode, each direction according to the number of channels of the acoustic signal It is described that the acoustic signal is subjected to spatial sound field processing so that the virtual sound source can be heard from that direction. According to this technology, it is said that the original sound quality and sound field feeling can be expressed even if a speaker is placed near the listener.

  Japanese Patent Application Laid-Open No. 2004-228561 describes that the position of each of a plurality of speakers is determined and the output destination of a stereo signal is switched according to the position of each speaker. According to this technology, the surround effect can be surely obtained without considering which channel the plurality of speakers are.

JP 2008-312096 A (released on December 25, 2008) JP 2007-60253 A (published March 8, 2007)

  However, the conventional technology does not support a multi-channel sound method in which a plurality of channels are arranged in a three-dimensional space, such as the 22.2 channel sound method described above. That is, in the related art, even if the acoustic effect can be controlled according to the horizontal position of the speaker, the acoustic effect cannot be controlled according to the vertical (vertical) direction position of the speaker. For this reason, in the prior art, when the speaker is not arranged at an appropriate position in the three-dimensional space (that is, an appropriate position in both the horizontal direction and the vertical direction), the audio signal for the multi-channel acoustic system is reproduced. In this case, the three-dimensional surround effect in the vertical and horizontal directions originally included in the content cannot be obtained satisfactorily.

  The present invention has been made in view of the above problems, and an object thereof is to obtain a good surround effect even when a speaker is not disposed at an appropriate position in a three-dimensional space.

In a multi-channel audio signal including a plurality of channels, wherein a multi-channel audio signal having a predetermined audio output position corresponding to each channel is output via a plurality of output channels,
For each of the output channels, the output channel is selected from the plurality of channels based on the position of the speaker connected to the output channel in the three-dimensional space and the audio output position corresponding to each of the plurality of channels. A main channel determining means for determining a main channel to be assigned to
Sub-channel determining means for determining a sub-channel assigned to the output channel from the plurality of channels for each of the output channels;
For each output channel, an output audio signal to be output via the output channel is generated using the audio signal of the main channel assigned to the output channel and the audio signal of the sub-channel assigned to the output channel. And an output audio signal generating means.

  According to this audio control apparatus, an appropriate channel corresponding to the position of the speaker can be determined as the main channel for each output channel. For this reason, the sound of the appropriate channel according to the position of the speaker can be output from each speaker as the main sound. In particular, according to the audio control apparatus, the main channel is determined in consideration of the position in the vertical direction in the three-dimensional space, and therefore the speaker is selected from a plurality of channels arranged three-dimensionally in the three-dimensional space. It is possible to determine an appropriate channel according to the position as the main channel.

  That is, according to the sound control device, the acoustic effect can be controlled according to the position of the speaker in the horizontal direction and the vertical direction, so that the appropriate position in the three-dimensional space (appropriate in both the horizontal direction and the vertical direction). Even if a speaker is not disposed at a desired position, a good surround effect can be obtained.

  In addition, according to the audio control device, for each output channel, the corresponding main channel is determined according to the position of the speaker. For example, even if the user mistakes the connection terminal or installation position of the speaker, the speaker An appropriate channel in accordance with the position of can be determined as the main channel. That is, no matter how the speakers are connected, the sound of an appropriate channel corresponding to the position can be output from each speaker.

  Further, according to the audio control apparatus, since the audio output position is predetermined for each of the plurality of channels, and most of the processing is performed based on the audio output position, the processing can be patterned. It is possible, and higher-speed processing can be realized without having to perform complicated arithmetic processing.

  In the audio control device, the output audio signal generation means downmixes, for each output channel, the audio signal of the main channel assigned to the output channel and the audio signal of the subchannel assigned to the output channel. Thus, it is preferable to generate an output audio signal to be output via the output channel.

According to this configuration, it is possible to output an output audio signal in which the sound of the appropriate main channel corresponding to the position of the speaker is downmixed as the main audio from each speaker, so that a favorable surround effect can be obtained. it can.
In the audio control device, the output audio signal generation unit is configured to localize the audio represented by the audio signal of the subchannel assigned to the output channel at the audio output position corresponding to the subchannel for each output channel. After correcting the frequency characteristics of the audio signal of the sub-channel assigned to the output channel using the head related transfer function, the audio signal of the main channel assigned to the output channel and the sub-channel assigned to the output channel It is preferable to generate an output audio signal to be output via the output channel by down-mixing the above signal.

  In particular, in the audio control device, the output audio signal generating means, for each output channel, the audio signal of the subchannel assigned to the output channel, the head related transfer function in the horizontal direction in the three-dimensional space, and the It is preferable to perform correction using a vertical head related transfer function in a three-dimensional space.

  According to this configuration, the sound of each channel can be localized at a predetermined sound output position in the three-dimensional space. That is, the sound of each channel can be localized at a predetermined sound output position not only in the horizontal direction but also in the vertical direction in the three-dimensional space. This makes it possible for the viewer to feel that the sound of each channel is heard from the predetermined sound output position. For this reason, even if the speaker is not disposed at an appropriate position in the three-dimensional space, a better and three-dimensional surround effect can be obtained.

  In the audio control device, the main channel determination means includes, for each output channel, a first direction that is a direction from a reference position of a speaker connected to the output channel, and each of the plurality of channels. Based on the second direction, which is the direction from the reference position, of the audio output position, the channel whose second direction is the closest to the first direction is the main channel assigned to the output channel. It is preferable to determine.

  According to this configuration, the main channel to be assigned to each output channel can be determined more efficiently and appropriately.

  In the audio control apparatus, the plurality of channels are grouped in advance for each region, and the sub-channel determination unit assigns, for each output channel, the group corresponding to the main channel assigned to the output channel. Preferably, the included channel is determined as a sub-channel assigned to the output channel.

  According to this configuration, it is possible to determine the sub-channel assigned to each output channel more efficiently and appropriately.

  The voice control device preferably further includes detection means for detecting a position of a speaker connected to the output channel for each output channel.

  According to this configuration, the position of the speaker can be specified more efficiently and reliably.

  In addition, a sound reproducing device according to the present invention includes the above sound control device.

  According to this audio reproduction device, it is possible to provide an audio reproduction device that has the same effect as the audio control device.

  In addition, a television receiver according to the present invention includes the above-described audio control device.

  According to the present television receiver, it is possible to provide a television receiver that has the same effect as the sound control device.

  The audio control method according to the present invention is a multi-channel audio signal including a plurality of channels, and a multi-channel audio signal having a predetermined audio output position corresponding to each channel is transmitted via the plurality of output channels. In the audio control method for outputting, for each of the output channels, the plurality of channels based on a position in a three-dimensional space of a speaker connected to the output channel and an audio output position corresponding to each of the plurality of channels. A main channel determining step for determining a main channel to be assigned to the output channel, a sub channel determining step for determining a sub channel to be assigned to the output channel from the plurality of channels for each output channel, Assigned to the output channel for each output channel An output audio signal generating step of generating an output audio signal to be output through the output channel using the audio signal of the main channel and the audio signal of the sub-channel assigned to the output channel. And

  According to this voice control method, the same effect as the voice control apparatus can be obtained by executing the voice control method.

  The program according to the present invention is a program for causing a computer to function as the voice control device, and causes the computer to function as each unit included in the voice control device.

  According to this program, when the computer executes the program, the computer can achieve the same effects as the voice control device.

  A recording medium according to the present invention is a computer-readable recording medium in which the program is recorded.

  According to this recording medium, it is possible to provide the program that makes it possible to realize the same effects as the sound control apparatus.

  According to the sound control device, the television receiver, the sound control method, the program, and the recording medium according to the present invention, even when the speaker is not disposed at an appropriate position in the three-dimensional space, a good surround effect is obtained. Can be obtained.

It is a block diagram which shows the structure of the television receiver which concerns on embodiment. It is a block diagram which shows the structure of the audio | voice control circuit with which the television receiver of this embodiment is provided. It is a flowchart which shows the procedure of the audio | voice control process by the audio | voice control circuit which concerns on embodiment. An example of the vector database memorize | stored in the memory | storage part is shown. It is a schematic diagram which shows each audio | voice output position defined in the vector database shown in FIG. An example of the head-related transfer function in the horizontal direction (front-rear direction and left-right direction) in the three-dimensional space stored in the storage unit is shown. The direction of each voice output position defined in the vector database shown in FIG. 4 is shown.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Outline of the television receiver 100)
First, with reference to FIG. 1, the outline | summary and structure of the television receiver 100 which concern on embodiment are demonstrated. FIG. 1 is a block diagram illustrating a configuration of a television receiver 100 according to the embodiment.

  The television receiver 100 shown in FIG. 1 receives various video contents such as terrestrial digital broadcasts and BS / CS digital broadcasts by a corresponding antenna and tuner, and reproduces the received video contents. Can be viewed by the viewer.

  In particular, the television receiver 100 can connect a plurality of external speakers 150 to construct a multi-channel sound system and output the audio of the video content from the plurality of external speakers 150 in a multi-channel manner. ing.

(Configuration of television receiver 100)
As shown in FIG. 1, the television receiver 100 includes a tuner unit 102, a display driving circuit 104, a display 106, an audio output circuit 108, an external device interface 110, a communication interface 112, an audio control circuit 120, and a microphone 122. ing.

(Tuner unit)
The tuner unit 102 includes a tuner, a demodulator, a demultiplexer, a video decoder, an audio decoder, and the like. The tuner receives broadcast waves of various video contents such as terrestrial digital broadcast and BS / CS digital broadcast via an external antenna. The demodulator obtains a TS (Transport Stream) of the video content by demodulating the broadcast wave received by the tuner. The demultiplexer separates the video signal and the audio signal of the video content from the TS obtained by the demodulator.

  Then, the video signal (compressed video data) separated from the TS by the demultiplexer is decoded by the video decoder, converted into digital video data, and supplied to the display driving circuit 104. On the other hand, the audio signal (compressed audio data) separated from the TS by the demultiplexer is decoded by the audio decoder and is supplied to the audio output circuit 108 as digital audio data.

(External device interface)
The external device interface 110 controls access to the external device. For example, the television receiver 100 is connected to an external device such as a BD recorder or an HDD recorder, so that the video of the video content reproduced by the external device is displayed on the display 106, or the sound is displayed on the external speaker 150. Can be output. At that time, access to the recorder is controlled by the external device interface 110.

(Communication interface)
The communication interface 112 controls access to a communication network such as a LAN or the Internet. For example, the television receiver 100 can display a video of video content downloaded from the Internet on the display 106 or output the sound from the external speaker 150 by connecting to the Internet. At that time, access to the Internet is controlled by the communication interface 112.

(Display drive circuit, display)
The display drive circuit 104 drives the display 106 in accordance with the supplied video signal, thereby causing the display 106 to display the video constituting the video content. The television receiver 100 of the present embodiment employs a liquid crystal display as the display 106, but other than this, an organic EL display, a plasma display, a cathode ray tube display, or the like may be employed.

(Audio output circuit, speaker)
The audio output circuit 108 drives the external speaker 150 in accordance with the supplied audio signal, thereby outputting the audio constituting the video content from the external speaker 150. The television receiver 100 has not only a few built-in speakers but also a plurality of external speakers 150 that can be connected. The number of external speakers 150 connected to the television receiver 100 can be arbitrarily changed by the user.

  For example, the television receiver 100 includes 24 output channels so that a 22.2 channel multi-channel sound system can be constructed, and an external speaker 150 is connected to each output channel. It is possible. That is, the television receiver 100 can connect 24 external speakers 150.

  For example, when 24 external speakers 150 are connected to the television receiver 100, in response to this, the audio output circuit 108 causes the audio constituting the video content to be output from the 24 external speakers 150. It is possible. The external speaker 150 may be a speaker built in the television.

  However, due to restrictions such as installation space and installation cost, 24 external speakers 150 cannot be connected to the television receiver 100, and a smaller number of external speakers 150 may be connected. For example, there may be a case where only a two-channel speaker built in the television receiver 100 is connected, or a case where a 5.1-channel theater system is connected to the outside.

(Voice control circuit)
The audio control circuit 120 controls the audio signal supplied to each external speaker 150 according to the number and position of the external speakers 150 connected to the television receiver 100.

  For example, in the audio control circuit 120, the number of channels (m) of the audio signal (hereinafter referred to as “input audio signal”) input to the audio control circuit 120 is the number (n) of the external speakers 150. ), The n-channel audio signal (hereinafter referred to as “output audio signal”) is generated by downmixing the m-channel input audio signal.

  Then, the audio control circuit 120 supplies the generated n-channel output audio signal to the audio output circuit 108. As a result, the audio signal of the corresponding channel is supplied to each of the n external speakers 150, and the audio of the corresponding channel is output from each external speaker 150.

  For example, the audio control circuit 120 has only two external speakers 150 connected to the television receiver 100 even though 22.2 channel input audio signals have been input to the audio control circuit 120. In this case, the output audio signal of 2 channels is generated by downmixing the input audio signal of 22.2 channels. As a result, audio from a plurality of channels corresponding to the external speaker 150 is output from each of the two external speakers 150.

  As described above, the television receiver 100 according to the present embodiment outputs audio of a plurality of channels from the plurality of external speakers 150 even when the number of external speakers 150 is small with respect to the number of channels of the input audio signal. Thus, a good acoustic effect can be obtained.

(Microphone 122)
Sound around the television receiver 100 is input to the microphone 122. As will be described later, the television receiver 100 can detect the position of each external speaker 150 based on the sound output from each external speaker 150 and input from the microphone 122. The microphone 122 may be built in the television receiver 100 or may be externally connected to the television receiver 100.

(Configuration of voice control circuit)
Next, with reference to FIG. 2, the structure of the audio | voice control circuit 120 with which the television receiver 100 of this embodiment is provided is demonstrated concretely. FIG. 2 is a block diagram illustrating a configuration of the audio control circuit 120 included in the television receiver 100 of the present embodiment.

  As shown in FIG. 2, the audio control circuit 120 includes a storage unit 200, a detection unit 202, a main channel determination unit 204, a sub channel determination unit 208, an output audio signal generation unit 210, and an audio signal output unit 212.

(Storage unit 200)
The storage unit 200 stores a vector database and a head related transfer function (HRTF). In the vector database, an audio output position in a three-dimensional space is defined for each channel of the multi-channel acoustic system. Each sound output position is a position where sound output at that position is recommended in order to obtain a good acoustic effect (surround effect).

  For example, the television receiver 100 according to the present embodiment can construct a 22.2 channel sound system by connecting 24 external speakers 150. Correspondingly, the vector database defines the audio output positions (that is, 24 audio output positions) of each channel constituting 22.2 channels.

  The head-related transfer function indicates the transfer characteristic of the sound from when the sound is output until the sound passes through the viewer's head and reaches the viewer's eardrum. This is indicated by the pressure level. Since the structure of the human head differs depending on the direction, the frequency characteristics when the sound reaches the eardrum differ depending on the direction of the position where the sound is output. Due to the difference in frequency characteristics, a human can specify the direction of the position where the sound is output. Using this principle, in the head-related transfer function, different frequency characteristics are defined for each direction in which the audio output position is based on the viewer. Therefore, by controlling the frequency characteristics of the sound based on this head-related transfer function, the direction in which the virtual output position of the sound is located can be freely adjusted.

  In particular, in the television receiver 100 of the present embodiment, the storage unit 200 includes a head-related transfer function in the horizontal direction (front-rear direction and left-right direction) in a three-dimensional space and a vertical direction (up-down direction) in a three-dimensional space. Are stored. By using these two head-related transfer functions, the television receiver 100 can freely adjust the direction in which the virtual output position of the sound is in any direction in the three-dimensional space. Yes.

(Detector 202)
The detection unit 202 detects the position of the external speaker 150 for each available output channel. Here, “available output channel” means an output channel to which the external speaker 150 is connected, but is not limited to this, and is an output channel or the like selected by the user. Also good.

  For example, the detection unit 202 detects the position of the external speaker 150 connected to the output channel by performing the following detection processes (1-1) to (1-5) for each output channel. For example, it is possible to connect 24 external speakers 150 to the television receiver 100, but when only two external speakers 150 are connected, the detection unit 202 detects the two external speakers 150. Each position of the single speaker 150 is detected.

  (1-1) The detection unit 202 reads an audio signal for position detection from a recording medium such as a memory, and supplies the audio signal to the audio signal output unit 212 by designating an output channel. The audio signal is preferably an impulse or a sine wave.

  (1-2) Thereby, the audio signal is supplied to the audio output circuit 108, and the audio signal is output from the designated output channel. Thereby, the sound based on the sound signal is output from the external speaker 150 connected to the designated output channel.

  (1-3) The detection unit 202 collects sound output from the external speaker 150 by the microphone 122. At this time, it is more preferable that the detection unit 202 uses at least three or more microphones 122 in order to obtain speaker spatial position information.

  (1-4) For each microphone 122, the detection unit 202, for each microphone 122, the difference between the output time from the external speaker 150 and the input time from the microphone 122, or the output level from the external speaker 150 and the microphone 122. The distance from the external speaker 150 to the microphone 122 is detected on the basis of at least one of the difference from the input level from.

  (1-5) The detection unit 202 determines the reference based on the position of each microphone 122 with respect to a predetermined reference position (for example, the center position of the display 106) and the distance from the external speaker 150 to each microphone 122. The spatial coordinate position of the external speaker 150 with respect to the position is specified.

(Main channel determination unit 204)
For each available output channel, the main channel determination unit 204 sets the output channel according to the spatial coordinate position of the external speaker 150 connected to the output channel (that is, the position detected by the detection unit 202). Determine the main channel to assign.

  In the television receiver 100, in the vector database stored in the storage unit 200, a plurality of audio output positions in a three-dimensional space are predetermined for each of a plurality of channels. Therefore, the main channel determination unit 204, for each output channel, based on the position of the external speaker 150 connected to the output channel and the audio output position of each of the plurality of channels defined in the vector database, A main channel to be assigned to the output channel is determined from the plurality of channels.

  For example, the main channel determination unit 204 determines that the direction (second direction) of the audio output position from the reference position (viewer position) is the position of the external speaker 150 from the reference position (viewer position). The channel closest to (first direction) is determined as the main channel to be assigned to the output channel.

  For example, when a speaker built in the television receiver 100 is used, the channel FLc and the channel FRc (see FIG. 5) can be assigned as main channels.

  Also, in accordance with the 5-channel multi-channel sound system, when five external speakers are arranged on the floor and used, channels FL, FR, FC, BL, BR (see FIG. 5) are assigned as main channels. Can be.

  Further, in accordance with the 5-channel multi-channel sound system, when five external speakers are suspended from the ceiling, channels TpFL, TpFR, TpFC, TpBL, and TpBR (see FIG. 5) are assigned as main channels. obtain.

(Sub-channel determination unit 208)
The subchannel determination unit 208 determines, for each output channel, a subchannel to be assigned to the output channel from among the plurality of channels (that is, a plurality of channels defined in the vector database).

  In the television receiver 100 of the present embodiment, the plurality of channels are grouped in advance for each area. In particular, in the television receiver 100 of the present embodiment, the grouping is defined for each combination of main channels. This definition is stored in, for example, a memory (for example, the storage unit 200) included in the television receiver 100. Then, in response to the determination of the main channel to be assigned to the output channel for each output channel, the sub-channel determination unit 208 sets the channel included in the group corresponding to the main channel as the output channel. Decide as subchannel to assign.

  For example, when the channel FL (front left side) and the channel FR (front right side) shown in FIG. 5 are determined as main channels, the sub-channel determination unit 208 sets 3 as the output channel having FL as the main channel. A channel group in the region on the left side (in the negative x-axis direction shown in FIG. 5) in the three-dimensional space and a channel group in the central region (that is, the x coordinate is 0) in the three-dimensional space are assigned to the output channel. The output channel determined as a channel and having FR as the main channel includes a group of channels on the right side in the three-dimensional space (the x-axis positive direction side in FIG. 5) and the central portion in the three-dimensional space (ie, the x coordinate) Is determined as a sub-channel to be assigned to the output channel.

  Note that, like the channel group in the central area in the above example, channels whose audio output positions can be intermediate positions of the positions of a plurality of speakers can belong to a plurality of groups. This is because it may be preferable to output the sound of such a channel from both speakers.

  Also, in the above definition, not all channels need to belong to any group, and there are channels that do not belong to any group (that is, channels whose sound is not output from any speaker). May be. This is because, depending on the arrangement of the speakers, it may be possible to obtain a natural surround effect without outputting the sound of that channel.

(Output audio signal generator 210)
For each output channel, the output audio signal generation unit 210 outputs the audio signal of the main channel assigned to the output channel (that is, the main channel determined by the main channel determination unit 204) and the sub-channel assigned to the output channel ( That is, an output audio signal to be output through the output channel is generated using the audio signal of the subchannel determined by the subchannel determination unit 208.

  For example, for each output channel, the output audio signal generation unit 210 down-mixes the audio signal of the main channel assigned to the output channel and the signal of the sub channel assigned to the output channel, thereby converting the output audio signal. Generate.

  In particular, for each output channel, the output audio signal generation unit 210 sets the output channel so that the audio represented by the audio signal of the sub channel assigned to the output channel is localized at the audio output position corresponding to the sub channel. After correcting the frequency characteristics of the assigned sub-channel audio signal using the head-related transfer function, the main channel audio signal assigned to the output channel and the sub-channel signal assigned to the output channel are downmixed. By doing so, it is also possible to generate an output audio signal.

(Audio signal output unit 212)
The audio signal output unit 212 outputs the output audio signal of each channel generated by the output audio signal generation unit 210 to the audio output circuit 108.

(Voice control processing procedure)
Next, with reference to FIG. 3, the procedure of the voice control process by the voice control circuit 120 will be described. FIG. 3 is a flowchart illustrating the procedure of the voice control process by the voice control circuit 120 according to the embodiment.

  Hereinafter, in the television receiver 100, the audio control process by the audio control circuit 120 will be described on the assumption that the output channel to which the plurality of external speakers 150 are already connected is recognized by the audio control circuit 120.

  First, the detection unit 202 detects the position of the external speaker 150 connected to the output channel for each available output channel (step S302).

  Next, the main channel determination unit 204 determines, for each output channel, the position of the external speaker 150 detected in step S302 and the audio output positions of each of the plurality of channels defined in the vector database. The main channel to be assigned to the output channel is determined from the plurality of channels (step S304).

  Next, in response to the determination of the main channel in step S304 for each output channel, the subchannel determination unit 208 determines a subchannel to be assigned to the output channel (step S306).

  Thereafter, when the input sound signal is input to the sound control circuit 120 (step S308), the output sound signal generation unit 210 assigns the sound signal of the main channel assigned in step S304 and the sound signal assigned in step S306 for each output channel. An output audio signal is generated using the sub-channel audio signal (step S310).

  Then, the audio signal output unit 212 outputs each output audio signal generated in step S310 to the audio output circuit 108 (step S312), and the audio control circuit 120 ends the audio control process.

  The television receiver 100 stores the information for specifying the main channel assigned in step S304 and the information for specifying the subchannel assigned in step S306 in a memory or the like included in the television receiver 100. It may be memorized. Thereby, the process of step S302-S306 can be abbreviate | omitted in the audio | voice control process after the next time. Then, when the configuration of the speaker is changed, the television receiver 100 may determine the main channel and the sub channel anew by performing the processes of steps S302 to S306.

(Example of vector database and head-related transfer function)
Here, an example of the vector database will be described with reference to FIG. 4 and FIG. FIG. 4 shows an example of a vector database stored in the storage unit 200. FIG. 5 is a schematic diagram showing each audio output position defined in the vector database shown in FIG.

  In the example shown in FIG. 4, the audio output positions of 22.2 channels are defined in the vector database. This 22.2 channel acoustic system includes three channel layers (upper layer 9 channels, middle layer 10 channels, lower layer 3 channels) in a three-dimensional space, and for LFE (Low Frequency Effects). It is configured to include two channels. Accordingly, 24 voice output positions are defined in the vector database.

  In the vector database, each voice output position is given a name composed of a combination of identifiers corresponding to the position. Specifically, “L”, “R”, “Tp”, “Bt”, “Si”, “B”, “F”, “C” are used as the identifiers, It means right side, upper side, lower side, side, rear side, front side, and center. In this embodiment, the name of the channel and the name of the audio output position are the same. For example, the name “TpFR” is assigned to the channel in the upper right part of the front and its audio output position.

In the vector database, each audio output position is defined by spatial coordinates. Each audio output position can also be represented by a vector from the origin (0, 0, 0). In this example, the center position (audio output position FC) of the display surface of the display 106 is set as the origin. For example, the audio output position BL can be expressed as a vector V _FC-BL . The audio output position BR can be expressed as a vector V _FC-BR .

(Example of main channel and sub-channel determination method)
The main channel determination unit 204 determines a main channel for each output channel based on this vector database. For example, it is assumed that the speaker A is connected to the output channel A included in the television receiver 100 and the speaker B is connected to the output channel B. Here, it is assumed that the speaker A is disposed at a position spA near the sound output position FL, and the speaker B is disposed at a position spB near the sound output position FR.

In this case, the main channel determination unit 204 approximates the direction of the vector V _SPA corresponding to the position spA of the speaker A and the direction of the vector V _FL corresponding to the audio output position FL, so that the audio output position FL The channel FL in which (front left side) is set is determined as the main channel assigned to the output channel A.

In addition, the main channel determination unit 204 is similar to the direction of the vector V _SPB corresponding to the position spB of the speaker B and the direction of the vector V _FR corresponding to the audio output position FR, so that the audio output position FR ( The channel FR in which the front right side) is set is determined as the main channel assigned to the output channel B.

  Then, the sub-channel determination unit 204 preliminarily associates the channel with the channel FL (for example, the channel in the left side (x-axis negative direction side) in the three-dimensional space and the central region in the three-dimensional space. Channel) is determined as a sub-channel to be assigned to output channel A.

  Further, the sub-channel determination unit 204 preliminarily associates the channel FR with the channel (for example, the channel in the right side (x-axis positive direction side) in the three-dimensional space and the central region in the three-dimensional space. Channel) is determined as a sub-channel to be assigned to the output channel B.

  Then, the output audio signal generation unit 210 downmixes the audio signal of the main channel (channel FL) assigned to the output channel A and the audio signal of the subchannel assigned to the output channel A, so that the output channel A An output audio signal is generated.

  Similarly, the output audio signal generation unit 210 downmixes the audio signal of the main channel (channel FR) assigned to the output channel B and the audio signal of the sub-channel assigned to the output channel B, so that the output channel B The output audio signal is generated.

(Example of output audio signal generation method)
As described above, when the main channel and the sub channel are determined for each of the plurality of channels, the audio signal generation unit 210, for each output channel, the audio signal of the main channel assigned to the output channel, and the output channel By downmixing the audio signal of the sub-channel assigned to the output channel, it is possible to generate an output audio signal that is output via the output channel.

For example, for the output channels A, the audio signal of the channel FL is the main channel and S _FL, 3-dimensional channel audio output position on the left side of the region is sub-channels that are arranged in space TpFL, TpBL, ··· the audio signal _{S TpFL, S TpBL,} and ..., channel FC audio output position is subchannels is arranged in the region of the central portion of the three-dimensional space, BC, an audio signal ... _{S FC} , S _BC ,..., The output audio signal generation unit 210 downmixes these audio signals using the following formula (Equation 1), thereby outputting the output audio signal S of the output channel A. _FL '' can be generated.

S _FL ″ = a × (S _FL + 1 / √2S _TpFL + 1 / √2S _TpBL +... + 1 / √2S _FC + 1 / √2S _BC +...) (Equation 1)
Similarly, for the output channel B, and audio signals of the channels FR is the main channel and S _FR, channel TpFR by-channel audio output located on the right side of the region of the three-dimensional space is arranged, TPBR, · · _.. , S _TpFR , S _TpBR ,..., And the audio signals of channels FC, BC,..., _Which are sub-channels whose audio output positions are arranged in the central region of the three-dimensional space. _{In the case of FC} , S _BC ,..., The output audio signal generation unit 210 downmixes these audio signals using the following formula (Equation 2), thereby outputting the output audio signal of the output channel B. S _FR ″ can be generated.

S _FR ″ = a × (S _FR + 1 / √2S _TpFR + 1 / √2S _TpBR +... + 1 / √2S _FC + 1 / √2S _BC +...) (Equation 2)
However, in the above formulas (Equation 1) and (Equation 2), a is a coefficient for reducing overflow (S _FL ″ and S _FR ″ become 1 or more), for example, 0 to 1 A value within the range is used. The overflow reduction may be realized by adjusting each downmix coefficient.

The output audio signal S _FL ″ of the output channel A and the output audio signal S _FR ″ of the output channel B generated by the audio signal generation unit 210 are output to the audio output circuit 108 by the audio signal output unit 212. . As a result, audio corresponding to the output audio signal S _FL ″ (that is, audio of each channel assigned to the output channel A) is output from the speaker A connected to the output channel A and connected to the output channel B. The sound corresponding to the output sound signal S _FR ″ (that is, the sound of each channel assigned to the output channel B) is output from the speaker B.

  In the above example, 1 / √2 is used as the downmix coefficient applied to the sub-channel, but the present invention is not limited to this. For example, as the downmix coefficient, a downmix coefficient (1/2, 1 / 2√2, etc.) often used in a conventional multi-channel sound system may be used. Also, it is applied to the sub channel so that the audio output position of the sub channel becomes weaker as the audio output position of the sub channel is farther from the audio output position of the main channel (the greater the angle difference in the vector direction). The downmix coefficient to be performed may be lowered. In the above example, the audio signal of the main channel is not multiplied by the downmix coefficient, but the audio signal of the main channel may be multiplied by the downmix coefficient. In addition, the audio signal of each sub-channel is multiplied by a downmix coefficient corresponding to the horizontal positional relationship with the main channel and a downmix coefficient corresponding to the vertical positional relationship with the main channel. May be.

(effect)
As described above, the television receiver 100 according to the present embodiment considers the position of the speaker connected to the output channel in the three-dimensional space in the three-dimensional space for each available output channel, and assigns the main channel to the output channel. An output audio signal is generated by determining a channel and downmixing the audio of the main channel as the main audio.

  As a result, according to the television receiver 100 of the present embodiment, the acoustic effect can be controlled according to the position of both the horizontal direction and the vertical direction of the speaker. Even if the speaker is not disposed at an appropriate position in both the vertical direction and the vertical direction, a good surround effect can be obtained.

(Example of processing using head-related transfer functions)
In the above example, the example in which the output sound signal is generated without performing the process using the head-related transfer function (sound image localization process) has been described. However, the output sound signal generation unit 210 performs the process using the head-related transfer function. (Sound image localization processing) can be performed to generate an output audio signal. Hereinafter, an example of processing using the head-related transfer function by the output audio signal generation unit 210 will be described with reference to FIGS. 6 and 7.

  FIG. 6 shows an example of the head-related transfer function stored in the storage unit 200. FIG. 6 shows, as an example, a head-related transfer function in the horizontal direction (front-rear direction and left-right direction) in the three-dimensional space among the head-related transfer functions stored in the storage unit 200. Actually, the storage unit 200 also stores a head-related transfer function in the vertical direction (vertical direction) in the three-dimensional space.

FIG. 7 shows the direction from the reference position of each audio output position defined in the vector database shown in FIG. In FIG. 7, each audio output position and the reference of each audio output position with the viewer position (center C of the cubic three-dimensional space shown in FIG. 5) as the reference position (origin (0, 0, 0)). The direction from the position is shown. Each audio output position is represented by spatial coordinates, and the direction of each audio output position from the reference position is represented by an azimuth angle and an elevation angle from the reference position. Here, as viewed from the origin, 0 ° elevation theta _el of z-axis negative direction (forward direction), the elevation angle theta _el of y-axis positive direction (upward direction) to 90 °. Further, when viewed from the origin, 0 ° azimuth angle theta _az in the z-axis negative direction (front direction), 90 ° azimuth angle theta _az of x-axis positive direction (the right direction), the z-axis positive direction (rear direction) 180 ° azimuth angle theta _az of the azimuth angle theta _az of x-axis negative direction (leftward) and 270 °.

  The output audio signal generation unit 210 corrects the frequency characteristics of the audio signal of each subchannel using the head-related transfer function so that the audio of each subchannel can be heard from a predetermined audio output position. The sound of each subchannel can be localized at the sound output position of the subchannel.

  In particular, the output audio signal generation unit 210 uses a horizontal head-related transfer function and a vertical head-related transfer function so that the audio of each subchannel can be heard from the audio output position in the three-dimensional space. Thus, by correcting the frequency characteristics of the audio signal of each sub-channel, the audio of each sub-channel can be localized at the audio output position corresponding to the sub-channel.

  For example, when the audio signal generation unit 210 generates an output audio signal of a certain output channel, the audio signal generation unit 210 performs the following processes (2-1) to (2-7) for each sub-channel corresponding to the output channel. The frequency characteristic of the audio signal of the subchannel is corrected. Then, the audio signal generation unit 210 generates an output audio signal of the output channel using the corrected audio signal of the subchannel.

  (2-1) The frequency characteristic associated with the horizontal direction (azimuth angle) of the virtual sound source (audio output position) of the subchannel from the reference position (viewer position) is stored in the storage unit 200. Obtained from the stored horizontal head-related transfer function.

  (2-2) The frequency characteristic associated with the vertical direction (elevation angle) of the virtual sound source (audio output position) of the sub-channel from the reference position (viewer position) is stored in the storage unit 200. Obtained from the vertical head-related transfer function.

  (2-3) Stores frequency characteristics associated with the horizontal direction (azimuth angle) of the position (audio output position of the main channel) where audio is actually output from the reference position (viewer position). Obtained from the horizontal head-related transfer function stored in unit 200.

  (2-4) The frequency characteristics associated with the vertical direction (elevation angle) of the position (audio output position of the main channel) where the sound is actually output from the reference position (viewer position) It is obtained from the vertical head related transfer function stored in 200.

  (2-5) The difference (frequency characteristic difference in the horizontal direction) between the frequency characteristic obtained in (2-1) and the frequency characteristic obtained in (2-2) is obtained.

  (2-6) A difference (frequency characteristic difference in the vertical direction) between the frequency characteristic obtained in the above (2-3) and the frequency characteristic obtained in the above (2-4) is obtained.

  (2-7) The frequency characteristic of the audio signal of the subchannel is corrected using the difference obtained in (2-5) above and the difference obtained in (2-6) above.

For example, when the main channel is FL and the sub-channel is TpFL, the audio signal generation unit 210 determines the difference between the frequency characteristics f _az (315 °) and f _az (315 °) for the azimuth angle θ _az ( Such a difference of the same value is set to 1.) and the difference between the frequency characteristics f _el (0 °) and f _el (45 °) with respect to the elevation angle θ _el is obtained. Then, the audio signal generation unit 210 uses the obtained differences {f _az (315 °) −f _az (315 °)} and {f _el (0 °) −f _el (45 °)} for the subchannel TpFL. Multiply the audio signal. Thereby, the sound of the subchannel TpFL is localized at the sound output position TpFL. That is, the sound of the subchannel TpFL is output from the sound output position FL as if it is heard from the sound output position TpFL.

  Hereinafter, an example of a mathematical expression used for output audio signal generation processing including subchannel audio signal correction processing will be described.

For example, for the output channel B, and audio signals of the channels FR is the main channel and S _FR, 3-dimensional channel audio output located on the right side of the region is sub-channels that are arranged in space TpFR, TpBR, ··· the audio signal _{S TpFR, S TpBR,} when a., the output audio signal generation unit 210, using the following equation (equation 3), performs correction processing of the audio signals of the respective sub-channel, By downmixing each of the audio signals, an output audio signal S _FR ′ of the output channel B can be generated.

S _FR '= a × {S _FR + 1 / √2 {f _az (45 °) −f _az (0 °)} {f _el (45 °) −f _el (45 °)} S _TpFR + 1 / √2 { f _az (135 °) −f _az (0 °)} {f _el (45 °) −f _el (45 °)} S _TpBR +...} ( _Equation 3)
However, in the above mathematical formula (Equation 3), a is a coefficient for preventing overflow (S _FR 'becomes 1 or more), and for example, a value in the range of 0 to 1 is used. In addition, prevention of overflow may be realized by adjusting each downmix coefficient.

(effect)
As described above, the television receiver 100 according to the present embodiment outputs the output so that the sound of each sub-channel corresponding to the output channel is localized at a predetermined sound output position for each available output channel. The frequency characteristic of the audio signal of each subchannel corresponding to the channel is corrected using the head-related transfer function.

  Thereby, according to the television receiver 100 of this embodiment, the sound of each subchannel can be localized at a predetermined sound output position in the three-dimensional space. That is, the sound of each subchannel can be localized at a predetermined sound output position not only in the horizontal direction but also in the vertical direction in the three-dimensional space. Thereby, it is possible to make the viewer feel that the audio of each sub-channel is heard from the predetermined audio output position. For this reason, even if the speaker is not disposed at an appropriate position in the three-dimensional space, a better and three-dimensional surround effect can be obtained.

(Program, storage medium)
Each function of the television receiver 100 described in the embodiment may be realized in hardware by a logic circuit formed on an integrated circuit (IC chip), or software using a CPU (Central Processing Unit). May be realized.

  For example, the television receiver 100 includes a CPU that executes instructions of a program that realizes each function, a ROM (Read Only Memory) that stores the program, a RAM (Random Access Memory) that develops the program, the program, and various programs. Various storage devices (recording media) such as a memory for storing data are provided. Then, the CPU reads out the programs stored in the various storage devices and executes the programs, whereby each function of the voice control circuit 120 can be realized.

  Examples of the recording medium include tapes such as magnetic tapes and cassette tapes, magnetic disks such as floppy (registered trademark) disks / hard disks, and disks including optical disks such as CD-ROM / MO / MD / DVD / CD-R. IC cards (including memory cards) / optical cards, semiconductor memories such as mask ROM / EPROM / EEPROM (registered trademark) / flash ROM, PLD (Programmable logic device) and FPGA (Field Programmable Gate) Logic circuits such as (Array) can be used.

  The program may be supplied to the television receiver 100 via a communication network. The communication network only needs to be able to transmit at least the program to the television receiver 100, and may be of any type. For example, the Internet, intranet, extranet, LAN, ISDN, VAN, CATV communication network, virtual private network, telephone line network, mobile communication network, satellite communication network, etc. can be used as the communication network. is there.

  Also, any kind of transmission medium for supplying the program to the television receiver 100 may be used. For example, a wired medium such as IEEE1394, USB, power line carrier, cable TV line, telephone line, ADSL (Asymmetric Digital Subscriber Line) line may be used as the transmission medium. As transmission media, infrared rays such as IrDA and remote control, Bluetooth (registered trademark), IEEE80211 wireless, HDR (High Data Rate), NFC (Near Field Communication), DLNA, cellular phone network, satellite line, terrestrial digital network You may use the thing by radio | wireless.

(Supplementary information)
The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the claims, and the technical means disclosed in different embodiments can be appropriately combined. Embodiments are also included in the technical scope of the present invention.

(Application object of the present invention)
For example, in the embodiment, the example in which the present invention is applied to a television receiver has been described. However, any device (for example, any device) can be used as long as the sound control process described in the embodiment can be performed. The present invention can also be applied to tuner devices, audio recorders / players (sound reproduction devices), audio amplifiers, HDD recorders / players, BD recorders / players, and the like.

  In the embodiment, the example in which the present invention is applied to a 22.2 channel sound system has been described. However, the present invention is also applied to other multi-channel sound systems (such as a 5.1 channel sound system). be able to.

(Speaker position detection method)
In the embodiment, as a method for detecting the position of the speaker, a method using sound for position detection is employed, but the method is not limited thereto. For example, as a method of detecting the position of the speaker, a method using an image obtained from a camera, an infrared sensor, an ultrasonic sensor, a laser sensor, or the like may be employed. Moreover, you may employ | adopt the structure which makes a user set the position of a speaker. For example, an image image in a three-dimensional space (for example, the legitimate body shown in FIG. 5) may be displayed graphically, and the position of the speaker may be set for the image image by the user.

(Speaker)
In the embodiment, the external speaker 120 is the target speaker. However, the television receiver 100 may include a built-in speaker. In this case, the built-in speaker is handled in the same manner as the external speaker 120 described in the embodiment. May be. That is, a multi-channel sound system may be constructed including a built-in speaker.

(Reference position)
Each voice output position is defined with the center C (see FIG. 5) of the cubic three-dimensional space shown in FIG. 5 as a reference position (viewer position). A position may be detected, and each sound output position may be defined using the detected position as a reference position.

  The present invention can be applied to various devices such as a television receiver, a tuner device, an audio player, an audio amplifier, an HDD recorder / player, a BD recorder / player, and a personal computer that can be incorporated into a multi-channel sound system. it can.

DESCRIPTION OF SYMBOLS 100 Television receiver 102 Tuner unit 104 Display drive circuit 106 Display 108 Audio | voice output circuit 110 External apparatus interface 112 Communication interface 120 Audio | voice control circuit (audio | voice control apparatus)
122 Microphone 150 External speaker 200 Storage unit 202 Detection unit (detection means)
204 Main channel determination unit (main channel determination means)
208 Sub-channel determination unit (sub-channel determination means)
210 Output audio signal generator (output audio signal generator)
212 Audio signal output unit

Claims (12)

In a multi-channel audio signal including a plurality of channels, wherein a multi-channel audio signal having a predetermined audio output position corresponding to each channel is output via a plurality of output channels,
For each of the output channels, and the position in the three-dimensional space of the speaker connected to the output channel, based on a sound output position corresponding to each of the plurality of channels contained in the multi-channel audio signal, the Main channel determining means for determining a main channel to be assigned to the output channel from the plurality of channels included in the multi-channel audio signal ;
Sub-channel determining means for determining, for each output channel, a sub-channel assigned to the output channel from among the plurality of channels included in the multi-channel audio signal ;
For each output channel, an output audio signal to be output via the output channel is generated using the audio signal of the main channel assigned to the output channel and the audio signal of the sub-channel assigned to the output channel. and an output audio signal generation means for,
The plurality of channels included in the multi-channel audio signal are:
It is grouped in advance by area,
The sub-channel determining means includes
For each output channel, a channel included in the group corresponding to the main channel assigned to the output channel is assigned to a sub-channel assigned to the output channel.
A voice control device characterized by being determined as a channel . The output audio signal generating means is
For each output channel, by downmixing the audio signal of the main channel assigned to the output channel and the audio signal of the subchannel assigned to the output channel, an output audio signal output via the output channel is obtained. The voice control device according to claim 1, wherein the voice control device is generated. The output audio signal generating means is
For each output channel, the frequency of the audio signal of the subchannel assigned to the output channel so that the sound represented by the audio signal of the subchannel assigned to the output channel is localized at the audio output position corresponding to the subchannel. After correcting the characteristics using the head-related transfer function, the audio signal of the main channel assigned to the output channel and the signal of the sub-channel assigned to the output channel are downmixed, so that The voice control apparatus according to claim 2, wherein an output voice signal to be output is generated. The output audio signal generating means is
For each output channel, the audio signal of the subchannel assigned to the output channel is corrected using the horizontal head related transfer function in the three-dimensional space and the vertical head related transfer function in the three-dimensional space. The voice control device according to claim 3. The main channel determining means includes
For each of the output channels, a first direction which is a direction from a reference position of a speaker connected to the output channel, and the audio of each of the plurality of channels included in the multi-channel audio signal Based on an output position and a second direction that is a direction from the reference position, a channel included in the multi-channel audio signal in which the second direction is closest to the first direction is The voice control device according to any one of claims 1 to 4, wherein the voice control device is determined as a main channel to be assigned to an output channel. Wherein for each output channel, the sound control apparatus according to any one of claims 1 to 5, further comprising a detection means for detecting the position of the speaker connected to the output channel. The group is set for each combination of main channels according to audio output position information corresponding to each channel included in the multi-channel audio signal.
The voice control apparatus according to any one of claims 1 to 6, wherein An audio reproduction device comprising the audio control device according to claim 1. A television receiver comprising the voice control device according to any one of claims 1 to 7. In a multichannel audio signal including a plurality of channels, a multichannel audio signal having a predetermined audio output position corresponding to each channel is output via the plurality of output channels.
For each of the output channels, and the position in the three-dimensional space of the speaker connected to the output channel, based on a sound output position corresponding to each of the plurality of channels contained in the multi-channel audio signal, the A main channel determining step for determining a main channel to be assigned to the output channel from the plurality of channels included in the multi-channel audio signal ;
A sub-channel determination step for determining, for each output channel, a sub-channel to be allocated to the output channel from among the plurality of channels included in the multi-channel audio signal ;
For each output channel, an output audio signal to be output via the output channel is generated using the audio signal of the main channel assigned to the output channel and the audio signal of the sub-channel assigned to the output channel. and an output audio signal generation step of viewing including,
The plurality of channels included in the multi-channel audio signal are:
It is grouped in advance by area,
In the sub-channel determination step,
For each output channel, a channel included in the group corresponding to the main channel assigned to the output channel is assigned to a sub-channel assigned to the output channel.
A voice control method characterized by determining as a channel .   A program for causing a computer to function as the voice control device according to any one of claims 1 to 7, wherein the program causes the computer to function as each unit included in the voice control device.   The computer-readable recording medium which has recorded the program of Claim 11.

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