JP5498275B2 - Sound reproduction apparatus, method and program - Google Patents

Description

  The present invention relates to an audio reproduction device that can be used as an audio reproduction device that limits a listening area only in a specific direction when reproducing sound in a room, or an audio reproduction device that efficiently distributes sound throughout the room. It relates to the method and the program.

  Conventionally, it has been necessary to measure the reverberation characteristics of a room in order to produce a sound reproducing device in which a listening area is limited only in a specific direction or a sound reproducing device that efficiently distributes sound throughout the room. Non-Patent Document 1 describes a method for measuring the reverberation time of a room. This method obtains reverberation characteristics depending on the radiation direction of the speaker sound by measuring the sound pressure by distributing microphones in the room. From the reverberation characteristics of this room, it is possible to know in which direction the sound can be absorbed most or diffused most. By knowing the reverberation characteristics of the room, it is possible to make a sound reproducing device that limits the listening area only in a specific direction, or a sound reproducing device that efficiently distributes sound throughout the room.

Heinrich Kuttorf, Koji Fujiwara, Takayuki Hidaka, “Sound of chamber acoustics and its theory”, Ichigaya Publishing Co., pp. 230-272, Aug. 2003.

  It takes time to measure the reverberation time of the entire room. Moreover, since the sound reproducing apparatus is adapted to the room, there is a problem that the versatility of the apparatus is lowered.

  The present invention has been made in view of such problems, and it is not necessary to measure the reverberation characteristics of the room, and the sound reproduction apparatus in which the listening area is limited only in a specific direction, or the sound signal efficiently in the entire room. It is an object of the present invention to provide a sound reproducing apparatus that spreads sound, a highly versatile sound reproducing apparatus that can be used, a method thereof, and a program.

  The sound reproducing apparatus of the present invention includes a directional speaker and a reflection direction control unit. The reflection direction control unit includes a reflection plate, reflected sound intensity measurement means, distance measurement means, integration means, and reflection direction control means. The reflector changes the direction of the acoustic signal emitted by the directional speaker. The reflected sound intensity measuring means radiates sound waves in all directions centering on the sound reproducing device, and measures the reflected sound from that direction to obtain the reflection intensity. The distance measuring means measures the distance to the object existing in the direction in which the reflection intensity is obtained. The integration means inputs the reflection intensity and the distance to the object, and arranges the directions in order according to the magnitude of the reflection intensity. The reflection direction control means controls the direction of the reflection surface of the reflector so that the acoustic signal from the directional speaker is directed to the uppermost direction in which the integration means are aligned.

  The sound reproducing device of the present invention measures the sound absorption characteristics of a room and, for example, directs the sound signal radiated by a directional speaker in the direction of sound absorption, and therefore provides a sound reproducing device that efficiently limits the listening area. I can do it. Also, if the acoustic signal is directed in the direction of reflecting the sound, the acoustic signal can be distributed throughout the room with a small output. Thus, a desired sound reproducing apparatus can be provided in accordance with the acoustic characteristics of the room.

  Since the sound reproduction apparatus of this invention determines the direction in which the sound from the directional speaker is directed from the reflection intensity and the distance to the object, the listening area can be set appropriately. Setting the listening area appropriately means, for example, that an acoustic signal is not directed to an area where the space is wide even if the reflection intensity is low. Assume that the listening area is limited by installing the sound reproducing device of the present invention in a relatively large room. At this time, since the sound reproducing apparatus of the present invention also measures the distance to the surrounding object, even if the reflection intensity is low, the listening area may be expanded by directing the sound signal in the direction where there is no object. No.

The figure which shows the function structural example of the sound reproduction apparatus 100 of this invention. The figure which shows the operation | movement flow of the reflection direction control part. The figure for demonstrating operation | movement of the reflected sound intensity measurement means 24 and the ranging means 25. FIG. The figure which shows the function structural example of acoustic reproduction apparatus 100 'provided with the relative direction search function. It is a figure which shows the example of the directional speaker 11 and the sound reception means 12 for directivity control, (a) is an example using the one point stereo microphone 120, (b) is a figure which shows the example using four microphones 121. It is. The figure which shows the function structural example for changing the shape of the reflecting plate. It is a figure which shows the example which changed the shape of the reflecting plate 21, (a) is an example made into convex shape, (b) is a figure which shows the example made into concave shape. The figure which shows the operation | movement flow of a relative direction search process. The figure which shows the function structural example of the sound reproduction apparatus 200 of this invention. The figure which shows the operation | movement flow of the sound reproducing apparatus.

  Embodiments of the present invention will be described below with reference to the drawings. The same reference numerals are given to the same components in a plurality of drawings, and the description will not be repeated.

  FIG. 1 shows an example of a functional configuration of the sound reproducing device 100 of the present invention. The sound reproducing device 100 includes a directional speaker 11 and a reflection direction control unit 20. The directional speaker 11 is a known speaker capable of changing the directivity of a radiated acoustic signal, such as a horn speaker, a parametric speaker, or a digital filter type speaker array.

  The reflection direction control unit 20 includes a reflection plate 21, reflected sound intensity measurement means 24, distance measurement means 25, integration means 23, and reflection direction control means 22. Each means excluding the reflecting plate 21 is realized by reading a predetermined program into a computer composed of, for example, a ROM, a RAM, a CPU, and the like, and executing the program by the CPU.

  The reflector 21 changes the direction of the acoustic signal radiated from the directional speaker 11. In the example shown in FIG. 1, an acoustic signal to which directivity characteristics are added is radiated vertically downward from the directional speaker 11, and the directivity direction of the acoustic signal is changed by 90 ° by the reflector 21.

  FIG. 2 shows an operation flow of the sound reproducing device 100. The reflected sound intensity measuring means 24 radiates sound waves in all directions centering on the sound reproducing device 100, and measures the reflected sound from the directions to obtain the reflection intensity (step S24). The radiated sound wave may be an audible sound or an ultrasonic wave.

  The distance measuring means 25 measures the distance to the object existing in the direction in which the reflected sound intensity measuring means 24 radiates the sound wave (step S25). The integration unit 23 uses the reflection intensity measured by the reflected sound intensity measurement unit 24 and the distance to the object measured by the distance measurement unit 25 as inputs, and arranges the directions in order according to the magnitude of the reflection intensity (step S23). ).

  For example, the direction in which the reflection intensity is attenuated by 10 dB when the distance to the object is within 1 m is ranked in the order of smaller reflection intensity. Further, the direction in which the distance to the object is as long as 10 m or more and the reflection intensity is attenuated by 10 dB is ranked in the direction where the reflection intensity is higher than the former. In this way, the reflection intensity in each direction is ranked using the reflection intensity and the distance to the object. In addition, the direction where the distance to the object is close and the reflection intensity is large is ranked in the direction with the larger reflection intensity.

  The reflection direction control means 22 controls the angle and direction of the reflection plate 21 so that the acoustic signal from the directional speaker 11 is directed to the uppermost direction in which the integration means 23 is aligned (step S22). This reflection direction control step may be referred to as a sound output step in the sense that the sound signal is directed in a desired direction.

  For example, when the integration unit 23 arranges the directions in the descending order of the reflection intensity, the sound can be efficiently distributed to the entire room even with a relatively low volume by directing the acoustic signal in the highest direction. Also, when the directions are arranged in order of increasing reflection intensity, there is an object that absorbs sound well in the uppermost direction. Therefore, when an acoustic signal is directed in that direction, the object and the sound reproducing device 100 The listening area can be limited in between.

  As described above, according to the sound reproducing device 100 of the present invention, it is possible to provide a desired sound reproducing device that matches the acoustic characteristics of the room without measuring the reverberation characteristics of the room.

  Here, the reflected sound intensity measuring means 24 and the distance measuring means 25 will be described in more detail. The reflected sound intensity measuring means 24 has been described as emitting sound waves in all directions. First, in the example of emitting sound waves in the horizontal direction centering on the sound reproducing device 100, the specific determination of the reflection intensity and the distance to the object is performed. Explain how.

  FIG. 3 shows specific examples of the reflected sound intensity measuring means 24 and the distance measuring means 25. The reflected sound intensity measuring means 24 emits a sound wave at every predetermined angle on the circumference of a predetermined radius centered on the sound reproducing device 100 and measures the reflected sound from that direction. 24x is provided. In the example shown in FIG. 3, 24 reflected sound sensors 24a to 24x are provided on a predetermined circumference at approximately central angles of 10 °. Since it becomes complicated, the reference numerals of all reflected sound sensors are not shown. Each of the reflected sound sensors 24a to 24x is configured by a set of a directional speaker and a directional microphone, for example. The directional microphone transmits a received sound signal that receives sound from the directional direction to the reflected sound intensity measuring means 24. The reflected sound intensity measuring means 24 obtains the reflection intensity in that direction from the output signal given to the directional speaker and the received sound signal received by the directional microphone.

  The distance measuring means 25 includes distance measuring sensors 25a to 25x so as to be paired with the reflected sound sensors 24a to 24x. The distance measuring sensor is an optical sensor that applies the principle of triangulation, for example, and can measure the distance to the reflecting object. As the distance measuring sensor, for example, a distance measuring sensor GP2D12 manufactured by Sharp can be used. The distance measuring sensors 25 a to 25 x detect a photocurrent proportional to the distance to the object in each direction and transmit it to the distance measuring means 25. The distance measuring means 25 measures the distance from the photocurrent to the object.

  As described above, the reflection intensity and the distance to the object can be measured by using the reflected sound sensor and the distance measuring sensor. By preparing the reflected sound sensors and distance measuring sensors as many as the number of directions to be measured, it is possible to measure the reflection intensity and distance in all directions.

  The distance measuring unit 25 has been described with an example in which a distance measuring sensor is provided in each direction. However, the distance measuring sensor optically scans the entire circumference of 360 ° with one sensor and measures the distance to surrounding objects. There is also a type to do. For example, there is C9159 made by Hamamatsu Photonics. The distance measuring means 25 may be configured using such a type of distance sensor.

  In addition, you may make it the reflection direction control means 22 control the angle and direction of the reflecting plate 21 based on the direction information input from the outside (refer the direction information shown with a broken line in FIG. 1). That is, when the position of the sound absorbing object is known, steps S24, S25, and S23 (see FIG. 2) are unnecessary if the acoustic signal is reflected in that direction.

  In the example of FIG. 1, the reflection direction control unit 20 has been described as being a known position below the directional speaker 11 in the vertical direction, but the positional relationship may be unknown. When the mutual position is unknown, the directional speaker 11 and the reflection direction control unit 20 are provided with a relative direction search function for searching for the mutual position.

(Relative direction search function)
FIG. 4 shows a functional configuration example of the sound reproducing device 100 ′ having a relative direction searching function. The sound reproducing device 100 ′ is different from the sound reproducing device 100 in that the sound receiving device 12 for directivity control and the sound emitting directivity control device 13 are provided on the directional speaker 11 side. Further, the reflection direction control unit 20 ′ is different from the sound reproduction device 100 in that the reflection direction control unit 20 ′ includes a reflection direction control sound receiving unit 26 and a reflection direction control unit 40 including a relative direction search function.

  The directivity control sound receiving means 12 is disposed at a fixed position in front of the directional speaker 11, and radiated sound reception of an acoustic signal radiated from the directional speaker 11 and a reflected sound reflected by the reflection direction control unit 20 '. Receive a signal. The sound emission directivity control means 13 controls the directivity of the directional speaker 11 so that the radiation reception signal is maximized.

  The reflection direction control sound receiving means 26 of the reflection direction control unit 20 ′ is disposed in front of the reflection plate 21 and receives the sound signal of the directional speaker 11 and the reflection sound reception signal of the reflection sound reflected by the reflection plate 21. To do. The reflection direction control means 40 controls the shape and direction of the reflection surface of the reflection plate 21 so that the reflected sound reception signal is maximized.

  As described above, by operating the sound emission directivity control means 13 and the reflection direction control means 40, the mutual relationship between the directivity speaker 11 side and the reflection direction control unit 20 ′ side is grasped. I can do it. Therefore, the sound reproducing device 100 ′ can function as a sound reproducing device even if the directional speaker 11 and the reflection direction control unit 20 ′ are arranged somewhat roughly.

  FIG. 5 shows a more specific configuration example of the directional speaker 11 and the directivity control sound receiving means 12 and will be described in more detail. FIG. 5A shows an example in which a one-point stereo microphone 120 is used as the directivity control sound receiving means 12. FIG. 5B shows an example using four microphones 121a to 121d. Each figure is a diagram seen from the front of the directional speaker 11, and shows an example in which the directional speaker 11 is a digital filter type speaker array including a plurality of speakers 11a to 11q.

  The digital filter type loudspeaker array is a well-known technique for changing the directivity of radiated sound by controlling the delay amount and amplitude amount of signals input to the speakers 11a to 11q.

  In FIG. 5A, the one-point stereo microphone 120 is disposed in the approximate center in front of the 16 speakers 11 a to 11 q constituting the directional speaker 11. Even if the directivity direction of the radiated sound from the directional speaker 11 changes, the position of the one-point stereo microphone 120 is fixed, and the change in the directional direction of the radiated sound and the reflected sound from the reflecting plate 21 are received.

  FIG. 5B shows two microphones on two axes orthogonal to the front of the center point of the 16 speakers 11 a to 11 q constituting the directional speaker 11, at a position equidistant from the center. 121b and 121d and microphones 121a and 121c are arranged. Even if the directivity direction of the radiated sound from the directional speaker 11 changes, the positions of the four microphones 121a to 121d are fixed, and the change in the directional direction of the radiated sound and the reflected sound from the reflecting plate 21 are received. To do.

  The position of the microphone is not limited to the above example. If two or more microphones are arranged at a fixed position in front of the directional speaker 11, a change in the directivity of the radiated sound can be detected, and the radiated sound and the reflected sound reflected by the reflecting plate 21 are detected. It is possible to receive a radiation reception signal consisting of

  The radiation reception signal is input to the sound emission directivity control means 13, and the sound emission directivity control means 13 controls the directivity direction of the directional speaker 11 so that the radiation reception signal is maximized. The sound emission directivity control means 13 controls the directivity direction of the directional speaker 11 constituted by, for example, a digital filter type speaker array by varying the delay amount and the amplitude amount of the signal input to each speaker. The sound emission directivity control means 13 can be easily realized by a known technique.

〔reflector〕
Here, a method for controlling the shape of the reflecting plate 21 will be described. FIG. 6 shows a functional configuration example of the shape control means 60 included in the reflection direction control means 40. The shape control means 60 controls the shape of the reflecting plate 21. Since the portion for controlling the direction of the reflecting plate 21 can be realized by a general method, it is omitted in FIG. 6 and only the configuration for controlling the shape of the reflecting plate 21 is shown. FIG. 6 is a view of the reflecting plate 21 as viewed from the side.

  The shape control means 60 includes reflector plate fixing frames 64a and 64b, a bending drive motor 65, a bending shaft 66, a bending direction initialization motor 67, and an initialization shaft 68. The upper and lower ends of the reflector 21 in the vertical direction are held by the reflector fixing frames 64a and 64b. One reflector fixing frame 64 a is connected to a bending drive motor 65 through a bending shaft 66. As the bending drive motor 65 rotates, the vertical position of the reflector fixing frame 64a moves up and down.

  The reflector 21 is made of, for example, a deformable thin metal plate or a plastic material such as an underlay, and can be deformed by lowering the position of the reflector fixing frame 64a. An initialization shaft 68 is connected to a substantially central surface of the reflecting plate 21, and the initialization shaft 68 can be moved back and forth by a bending direction initialization motor 67.

FIG. 7 shows a case where the reflecting plate 21 is deformed into a convex surface (FIG. 7A) and a concave surface (FIG. 7B). When the shape of the reflecting plate 21 is convex, the bending direction initialization motor 67 drives the initialization shaft 68 forward at the same time or before the bending drive motor 65 starts to rotate. Thereafter, the initialization shaft 68 is brought into a free state without applying a driving force. Such switching of the state can be easily realized by configuring the bending method initialization motor 67 with, for example, a linear motor.
And the reflecting plate 21 can be deform | transformed into a convex surface because the position of the reflecting plate fixing frame 64a falls.

  When the shape of the reflecting plate 21 is concave, the bending direction initialization motor 67 drives the initialization shaft 68 rearward at the same time as or before the bending drive motor 65 starts to rotate. Thereafter, the initialization shaft 68 is brought into a free state without applying a driving force. In this state, when the position of the reflector fixing frame 64a is lowered, the reflector 21 is deformed into a concave surface.

  As described above, the shape of the reflecting plate 21 can be freely deformed from a flat surface to a convex surface and from a flat surface to a concave surface. By utilizing the change in the shape of the reflecting plate 21, the relative direction search can be performed efficiently.

  FIG. 8 shows an operation flow of a relative direction search operation in which the radiated sound and the reflected sound are automatically opposed to each other. When the positions of the directional speaker 11 and the reflection direction control unit 20 ′ are unknown, it is easier to find the relative direction if the reflected sound reflected by the reflection plate 21 is diffused. Therefore, at the initial stage of searching for the relative direction, it is convenient to place the reflector 21 in a convex shape (step S60). Then, the direction of the reflecting plate 21 is fixed, and the directivity direction of the directional speaker 11 is determined in the direction in which the radiation sound reception signal is maximized (step S13). Thereafter, the shape of the reflecting plate 21 is changed to a plane step by step (step S61).

  After changing the shape of the reflecting plate 21 by one step, the direction of the reflecting plate 21 is controlled so that the reflected sound signal is maximized by changing the direction of the reflecting plate 21 while the shape of the reflecting plate 21 is fixed (step S40). By repeating the operations of Step S13, Step S61, and Step S40 until the reflected sound reception signal becomes maximum, the radiated sound and the reflected sound can be made to be opposite (Yes in Step S41). By thus changing the shape of the reflecting plate 21, the relative direction search can be performed efficiently. In addition, when it is desired to grasp the position of the reflection direction control unit 20 'more accurately, the reflection plate 21 may be formed in a concave shape. The cooperation of the relative direction searching operation in the sound emission directivity control means 13 and the reflection direction control means 40 is performed by connecting the sound emission directivity control means 13 and the reflection direction control means 40 to a signal line (13 and 40 in FIG. 4). It can be easily realized by linking with a broken line) and communicating each other's operation status to the other party. The communication by the wired connection may be replaced with infrared communication or short-range wireless communication.

  When the positional relationship between the directional speaker 11 and the reflection direction control unit 20 is known, the relative direction search operation can be omitted, and the reflector 21 is not limited to one that can control the shape.

  After the positional relationship between the directional speaker 11 and the reflection direction control unit 20 is clarified by the relative direction search function described above, the reflection direction control means 40 performs the reflection direction control process described with reference to FIG. As a result, the sound reproducing device 100 ′ can function as a sound reproducing device even when the positions of the directional speaker 11 and the reflection direction control unit 20 ′ are unknown.

  FIG. 9 shows a functional configuration example of the sound reproducing device 200 of the present invention. The operation flow is shown in FIG. The sound reproducing device 200 includes a directional speaker 91, directivity control means 90, integration means 23, reflected sound intensity measurement means 24, and distance measurement means 25.

  The sound reproducing device 200 is different from the sound reproducing device 100 in that the sound reproducing device 200 includes a directional speaker 91 and directivity control means 90 so as to directly radiate sound signals from the directional speaker 91 in the direction aligned by the integrating means 23. It is a thing. That is, the directivity control means 90 is different in that the directivity direction of the directional speaker 91 is directly directed to the uppermost direction in which the integration means 23 are aligned (step S90).

  When the directional speaker 91 is constituted by, for example, a digital filter type speaker array so that an acoustic signal is radiated in a direction aligned with the integration unit 23, the directivity control unit 30 includes a plurality of speakers constituting the digital filter type speaker array. Controls the amount of delay and amplitude of the signal input to. As a result, the sound reproducing device 200 directly radiates an acoustic signal in a direction where the reflection intensity is small or large.

  When the processing means in the above apparatus is realized by a computer, the processing contents of functions that each apparatus should have are described by a program. Then, by executing this program on the computer, the processing means in each apparatus is realized on the computer.

  The program describing the processing contents can be recorded on a computer-readable recording medium. As the computer-readable recording medium, for example, any recording medium such as a magnetic recording device, an optical disk, a magneto-optical recording medium, and a semiconductor memory may be used. Specifically, for example, as a magnetic recording device, a hard disk device, a flexible disk, a magnetic tape or the like, and as an optical disk, a DVD (Digital Versatile Disc), a DVD-RAM (Random Access Memory), a CD-ROM (Compact Disc Read Only). Memory), CD-R (Recordable) / RW (ReWritable), etc., magneto-optical recording medium, MO (Magneto Optical disc), etc., semiconductor memory, EEP-ROM (Electronically Erasable and Programmable-Read Only Memory), etc. Can be used.

  The program is distributed by selling, transferring, or lending a portable recording medium such as a DVD or CD-ROM in which the program is recorded. Further, the program may be distributed by storing the program in a recording device of a server computer and transferring the program from the server computer to another computer via a network.

  Each means may be configured by executing a predetermined program on a computer, or at least a part of these processing contents may be realized by hardware.

Claims (4)

A sound reproducing device including a directional speaker and a reflection direction control unit,
The reflection direction control unit
A reflector that changes the direction of the acoustic signal emitted by the directional speaker;
Reflected sound intensity measuring means for radiating sound waves in all directions centering on the sound reproducing device and measuring the reflected sound from that direction to obtain the reflected intensity;
Ranging means for measuring the distance to an object present in the direction in which the reflection intensity is obtained;
An integrating means for aligning the directions in order according to the magnitude of the reflection intensity, using the reflection intensity and the distance to the object as inputs;
Reflection direction control means for controlling the direction of the reflection surface of the reflector so that the acoustic signal is directed in the uppermost direction in which the integration means are aligned;
A sound reproducing apparatus comprising: A sound reproducing device including a directional speaker,
Reflected sound intensity measuring means for radiating sound waves in all directions centering on the sound reproducing device and measuring the reflected sound from that direction to obtain the reflected intensity;
Ranging means for measuring the distance to an object present in the direction in which the reflection intensity is obtained;
An integrating means for aligning the directions in order according to the magnitude of the reflection intensity, using the reflection intensity and the distance to the object as inputs;
Directivity control means for directing the directivity direction of the directional speaker in the uppermost direction in which the integration means are aligned;
A sound reproducing apparatus comprising: A reflection intensity measuring step for radiating sound waves in all directions centering on a sound reproducing device including a directional speaker and measuring reflected sound from the directions to obtain a reflection intensity;
A distance measuring step for measuring a distance to an object existing in the direction in which the reflection intensity is obtained;
An integration step of aligning the directions in order according to the magnitude of the reflection intensity with the reflection intensity and the distance to the object as inputs;
A sound output step for directing the directivity direction of the directional speaker in the uppermost direction in which the integration steps are aligned;
A sound reproduction method including: Program for sound reproduction method according to claim 3, causes the computer to execute.

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