KR101381203B1 - Surround audio realization apparatus and surround audio realization method - Google Patents

Abstract

According to an aspect of the present invention, a surround audio implementing apparatus includes: a mixing unit configured to output a sum and a difference of output signals of first and second unidirectional microphone members facing front and rear surfaces, respectively; A direction function generator for providing a unidirectional directional signal in an arbitrary direction by using the output signal from the mixing unit and the output signal from the bidirectional directional microphone member facing in the left and right directions; And a channel synthesizer for synthesizing and outputting a channel corresponding to the channel of the surround sound according to the direction function provided by the direction function generator. According to the present invention, it is possible to obtain a surround audio signal in a small space without being limited in space, to be portable at a low cost.

Description

Surround Audio Implementer and Surround Audio Implementer {SURROUND AUDIO REALIZATION APPARATUS AND SURROUND AUDIO REALIZATION METHOD}

The present invention relates to a microphone, a surround audio implementation, a surround audio implementation, and a surround audio input.

Audio technology is moving away from the video-dependent field to surround sound (stereophonic) technology that enables more realistic and realistic sound. In recent years, commercial cinemas have implemented the surround sound to enhance viewers' immersion and improve the quality of movies. This movement is expanding into the home theater market.

However, the surround sound market suffers from a lack of content. For example, in order to obtain a 5.1 channel sound by installing a plurality of microphones surrounding a sound source, various equipments are required and expensive equipment is not used widely because of disadvantages. In view of such a problem, a technique for extending a stereo signal to 5.1 channels is known, but there are still difficulties in securing direction and securing performance of sound phase due to lack of signal of a sound source.

The present invention has been proposed to solve the above problems, and proposes an apparatus and method capable of realizing surround sound with a simple improvement.

According to an aspect of the present invention, there is provided a surround audio implementing apparatus including: a mixing unit configured to output a sum and a difference of output signals of first and second unidirectional microphone members facing front and rear surfaces, respectively; A direction function generator for providing a unidirectional directional signal in an arbitrary direction by using the output signal from the mixing unit and the output signal from the bidirectional directional microphone member facing in the left and right directions; And a channel synthesizer for synthesizing and outputting a channel corresponding to the channel of the surround sound according to the direction function provided by the direction function generator.

The channel synthesizer may include: an averager capable of synthesizing five channels and averaging the output signals of the first and second unidirectional microphone members; And a low pass filter configured to low pass the output signal passing through the averager to provide a woofer signal. Further, the direction function in the direction function generation unit is y _θ (n) = (o _r (n) + cos θb _r (n) + sinθ · b _S (n)) / 2, where b _S (n) is the n th sample of the output signal of the bidirectional directional microphone member, and b _r (n) and the o _r (n) are the n th sample of the output signal of the first and second unidirectional directional microphone members, It is different from the sum of u _F (n) and u _B (n), and θ can be defined in any direction.

According to an aspect of the present invention, there is provided a method of implementing surround audio, comprising: preparing a predetermined sound source obtained from first and second unidirectional microphone members facing front and rear surfaces, and bidirectional directional microphone members facing left and right directions; Mixing a sum and a difference of output signals from the two unidirectional microphone members to obtain a signal corresponding to the sum and a signal corresponding to the difference; Combining the two signals obtained in the mixing step with a sound source provided from the bidirectional directional microphone member to obtain a direction function for a unidirectional directional signal having an arbitrary direction as a factor; And synthesizing the sound in an arbitrary angle channel according to the specification of the surround sound system using the direction function.

The method of implementing surround audio includes: generating an omni-directional signal by averaging signals obtained from the first and second unidirectional microphone members; And generating a woofer signal by passing the non-directional signal through a low pass filter for passing only a specific low frequency. Thus, a full 5.1 channel can be realized.

In addition, the surround audio input apparatus according to the present invention, the microphone receiving portion that is housed at least three microphone members therein; And a connection port electrically connected to the microphone and connected to another electronic device, wherein the microphone includes two unidirectional directional microphone members that largely receive sound in the front-rear direction with respect to a first direction, and the first direction intersects with the first direction. A bidirectional microphone member for receiving a large amount of sound in the direction can be included.

In addition, the microphone according to the present invention includes two unidirectional mic members each receiving a large amount of front and rear sound; And it may include a bidirectional directional microphone member that receives a large amount of sound in the left and right directions.

According to the present invention, it is possible to obtain a surround audio signal in a small space without being limited in space, to be portable at a low cost.

1 is a microphone according to the embodiment.
2 is a beam pattern of the microphone shown in FIG.
3 is a system configuration diagram of a surround audio implementing apparatus according to an embodiment.
4 is a beam pattern of a signal obtained by processing an input signal of a microphone member.
5 is a channel-specific beam pattern of 5.1 channels obtained according to an experiment.
6 is a flow chart illustrating a method of implementing surround audio.
7 is a view illustrating a surround audio input device applied to a mobile phone, and FIG. 8 is a perspective view of the surround audio input device.

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

1 shows a microphone according to an embodiment.

Referring to Figure 1, the microphone is provided with three directional microphone members. In detail, the first unidirectional microphone member 1 facing the front surface, the second unidirectional microphone facing the rear surface (hereinafter also referred to as unidirectional), the microphone member 2 and the bidirectional orientation facing the left and right (hereinafter also referred to as bidirectional) Microphone member 3 is included. The first unidirectional microphone member 1 largely receives sound in the positive y-axis direction (hereinafter referred to as 0 degree or the front side) in the drawing. The second unidirectional microphone member 2 greatly receives sound in the y-axis direction (hereinafter, also referred to as 180 degrees or rear side) in the figure. The bidirectional directional microphone member 3 is largely accommodated in the positive x-axis direction and the negative x-axis direction.

FIG. 2 is a beam pattern of the microphone shown in FIG. 1. Referring to FIG. 2, it can be seen that the first and second unidirectional mic members 1 and 2, which are represented by M +, greatly receive sound in the positive y-axis direction and the negative y-axis direction. The bidirectional mic member 3 is shown as S + and S-, which can be seen to greatly receive sound in the positive and negative x-axis directions.

The audio signal received through the three microphone members described above allows the surround sound to be reproduced through a predetermined process. Exemplary surround sound may include 5.1 channels, and 7.1 channels may be possible. In addition, various types of surround channels presented may be implemented.

3 is a system configuration diagram of a surround audio implementing apparatus according to an embodiment.

Referring to FIG. 3, the signal input from the first unidirectional mic member 1 and 2 is inputted as U _F , the signal input from the second unidirectional directional microphone member 2 is inputted as U _B , and bidirectional. The signal input from the directional microphone member 3 is input to B _S. Among the input signals, U _F and U _B are mixed by the mixing unit 11. In the mixing unit, a process of obtaining a bidirectional signal and an omnidirectional signal by obtaining a sum and a difference of U _F and U _B as an input signal is performed. The process of calculating the sum and difference of the input signals may be represented by Equations 1 and 2.

In Equations 1 and 2, u _F (n) and u _B (n) represent n-th samples of the input signals of the first and second unidirectional microphone members 1 and 2, respectively.

As shown in Equation 1, when u _B (n) is subtracted from u _F (n), a bidirectional signal having a direction axis at 0 degrees is provided. At this time, the signal phase difference of 180 degrees occurs in the front and rear. As shown in Equation 2, when u _F (n) and u _B (n) are summed, an omnidirectional signal is generated. Referring to b _r (n), o _r (n), and B _S provided by the sum and difference of the u _F (n) and u _B (n) as shown in FIG.

The bidirectional signals b _r (n) generated in Equations 1 and 2 and the non-directional signals o _r (n) are transmitted to the direction function generator 13. Along with this, B _{S is} also transmitted to the direction function generator 13. The direction function generation unit 13 provides a direction function for providing a unidirectional directional signal for an arbitrary direction by utilizing b _r (n), o _r (n), and B _S. The direction function is represented by equation (3).

Here, b _S (n) denotes the n th sample of the input signal of the bidirectional directional microphone member 3. According to Equation 3, when two co-directional signals b _r (n) and b _S (n) are rotated by arbitrary angles, the cosine and sine values are respectively rotated by arbitrary directions (θ). A bidirectional signal can be obtained. By adding o _r (n), which is a non-directional signal, to the rotated bi-directional signal, a portion having a phase difference of 180 degrees is eliminated, and only components having the same phase remain, so that the direction is rotated by an arbitrary direction (θ). Can only generate a directional signal

According to Equation 3, it can be seen that the unidirectional directional signal for any direction can be obtained. That is, the signal U _F input from the first unidirectional microphone member 1, 2, the signal U _B input from the second unidirectional microphone member 2, and the bidirectional directional microphone member 3. By using the signal (B _S ) input from the, it is possible to obtain a unidirectional signal for any direction.

Information according to Equation 3 is transmitted to the channel synthesizer 15 to synthesize the sound allocated to each channel according to each direction of the 5.1 channel. For example, ITU-R BS.755 [7] recommends the playback environment for 5.1-channel systems. Specifically, in the 5.1 channel, 0 degrees (Center: C), +30 degrees (Front Left: FL), -30 degrees (Front Right: FR), +110 degrees (Real Left: RL), and -110 degrees One-way directional signals in each direction corresponding to (Real Right: RR) are synthesized and output.

According to an embodiment, in order to improve the directivity of the 5.1-channel system recommended in the ITU-R BS.755 [7], a signal of about 10 degrees with respect to the direction determined by each channel is also synthesized. It is desirable to increase the directivity. Equation 4 shows a signal for each channel provided accordingly.

According to Equation 4, Y _ch (n) means an output signal of each channel (C, FL, FR, RL, RR), and before and after each direction (θ) defined in ITU-R BS.755 [7]. The synthesized signal within the range of 10 degrees is output as the combined signal of each channel. If the surround sound is 5.1 channel, the sound synthesized according to Equation 4 will be output at an angle according to ITU-R BS.755 [7]. However, if the channel is changed to 7.1 channel, Therefore, the sound is output by changing the direction and the number of channels so that the corresponding surround sound can be reproduced.

On the other hand, it is also necessary to provide a Low Frequency Enhancement (LFE), which is a channel of 5.1. The woofer signal is a low band signal having no directivity. In order to provide the woofer signal, an averager 12 and a low pass filter (LPF) 14 are used. First, in the averager 12, a signal U _F input from the first unidirectional microphone member 1 and a signal U _B input from the second unidirectional microphone member 2 are received. The omni-directional signal is obtained from the average value of the signals. Thereafter, the low pass filter 14 passes the omni-directional signal generated by the averager 12 at a cutoff frequency of 120 Hz to produce an LFE.

<Experimental Example>

The experiment was performed by implementing the surround audio implementer as described above under the following conditions.

In an audio room with less reverberation, a white noise sound source is used, and three microphone members coaxially positioned are installed in the structure of FIG. Placed.

The sound was reproduced through the speaker, and the microphone members were rotated 360 degrees at intervals of 10 degrees.

FIG. 5 shows a beam pattern for each channel of 5.1 channels obtained according to the experiment. Referring to FIG. 5, it can be seen that the beam pattern is smoothly formed according to the direction of each channel.

Hereinafter, a method of implementing surround audio will be described. 6 is a flowchart illustrating a method of implementing surround audio.

Referring to FIG. 6, the method for implementing surround audio according to the embodiment prepares a sound source obtained from each microphone member configured as shown in FIG. 1 (S1). In this case, each microphone may be prepared as a first and second unidirectional mic members 2 facing the front and rear, respectively, and a bidirectional directional microphone member 3 facing the left and right directions. Of the prepared sound sources, the sum and difference of the output signals from the two unidirectional microphone members 1 and 2 are mixed to obtain a signal corresponding to the sum and a signal corresponding to the difference (S2). The two signals obtained in the mixing step S2 and the sound source provided from the bidirectional directional microphone member 3 are combined to obtain a direction function for a unidirectional signal having an arbitrary direction as a factor (S3). A sound of a channel corresponding to an arbitrary angle is synthesized in accordance with the standard of the surround sound system exemplified as 5.1 channels in the function obtained in the direction function generating step S3 (S4).

On the other hand, in order to obtain a non-directional woofer signal irrespective of the angle, an omnidirectional signal is generated as an average value of the signals obtained from the first and second unidirectional directional microphone members 2 (S11), and the omnidirectional signal is specified. It can obtain by passing the low pass filter which passes only a low frequency (S12).

Each signal provided through the channel synthesis step S4 and the low pass step S12 is output as an acoustic signal suitable for a surround sound system such as a 5.1 channel or a 7.1 channel (S5).

8 is a perspective view of a surround audio input device.

Referring to FIG. 8, a surround audio input device includes a connection port 103 that can be connected to an electronic device such as a mobile phone, and three microphone members 1 connected to the connection port and provided in the configuration shown in FIG. 1. There is provided a microphone accommodating portion 104 in which (2) and (3) are housed and provided with a structure such as a slit for allowing sound propagation on the outer surface. The three microphone members may include first and second unidirectional microphone members facing the front and rear surfaces, and a bidirectional microphone member facing the left and right directions.

According to the surround audio input device, the microphone accommodating part 104 is provided in a structure capable of introducing external sound into the inside in at least two directions. The internal microphones 1, 2 and 3 can sufficiently receive external sounds, convert them into electrical signals, and then transmit them to the electronics through the connectors.

7 illustrates that a mobile phone can be used as an example of an electronic device. According to FIG. 7, the connector may be inserted into the mobile phone.

The surround audio input device may be provided as a mounting type of an electronic device. Therefore, the connector 103 may not be provided in the form of a rigid rod such as a general jack, but may be provided in the form of a conductive wire or the like. In this case, it may be provided in the form of being inserted into the electronic device.

The spirit of the present invention is not limited to the above embodiments, and those skilled in the art who understand the spirit of the present invention can easily suggest other embodiments falling within the scope of the same idea by adding, changing, deleting, and adding small elements. However, this will also be included within the scope of the present invention.

According to the present invention, it is possible to obtain surround audio in a small space without portability and to be portable at a small cost. Since the sound source of the surround sound can be conveniently obtained, it is possible to solve the difficulties of the stereophonic sound industry caused by the lack of content.

1,2: unidirectional directional microphone member
3: 2-way directional microphone member

Claims (8)

A mixing unit for outputting a sum and a difference of output signals of the first and second unidirectional microphone members facing the front and the rear;
A direction function generator for providing a unidirectional directional signal in an arbitrary direction by using the output signal from the mixing unit and the output signal from the bidirectional directional microphone member facing in the left and right directions; And
And a channel synthesizer for synthesizing and outputting a channel corresponding to a channel of a surround sound according to the direction function provided by the direction function generator.
The direction function is,
y _θ (n) = (o _r (n) + cos θ b _r (n) + sin θ b _S (n)) / 2,
Here, b _S (n) is the n th sample of the output signal of the bidirectional microphone member,
b _r (n) and o _r (n) are different from the sum of u _F (n) and u _B (n), which is the n th sample of the output signal of the first and second unidirectional microphone members,
θ is any direction,
Surround audio implementer given by. The method according to claim 1,
In the channel synthesizer, a surround audio implementor for synthesizing five channels. The method according to claim 1,
An averager for averaging output signals of the first and second unidirectional microphone members; And
And a low pass filter providing a woofer signal by low-passing the output signal passing through the averager. delete Preparing a predetermined sound source obtained from the first and second unidirectional directional microphone members facing the front and rear surfaces, and the bidirectional directional microphone members facing the left and right directions, respectively;
Mixing a sum and a difference of output signals from the two unidirectional microphone members to obtain a signal corresponding to the sum and a signal corresponding to the difference;
Combining the two signals obtained in the mixing step with a sound source provided from the bidirectional directional microphone member to obtain a direction function for a unidirectional directional signal having an arbitrary direction as a factor; And
Using the directional function, to synthesize the sound in any angle channel in accordance with the specification of the surround sound system
The direction function is,
y _θ (n) = (o _r (n) + cos θ b _r (n) + sin θ b _S (n)) / 2,
Here, b _S (n) is the n th sample of the output signal of the bidirectional microphone member,
b _r (n) and o _r (n) are different from the sum of u _F (n) and u _B (n), which is the n th sample of the output signal of the first and second unidirectional microphone members,
θ is any direction,
How to implement surround audio. 6. The method of claim 5,
Making an omnidirectional signal by averaging the signals obtained from the first and second unidirectional microphone members; And
And generating a woofer signal by passing the omni-directional signal through a low pass filter that passes only a specific low frequency. delete delete

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