KR102121860B1 - Separate sound field forming apparatus used in digital signage and digital signage system including the same - Google Patents

Abstract

The present invention relates to an independent sound field forming apparatus for digital signage and a digital signage system including the same, and more specifically, a specific area on the front side of the screen of the digital signage that sounds related to the content displayed on the screen of the digital signage. Independent sound field forming apparatus for digital signage that can be heard well in the digital signage system including the same.
An apparatus for forming an independent sound field for digital signage according to an embodiment includes an input unit that receives a sound source signal related to content displayed through a screen of a digital signage; An interface unit formed on a front side of the screen of the digital signage and controlling a bright zone, which is an area where sound is heard above a threshold; A filter unit including a digital filter, updating a filtering coefficient corresponding to a control signal from the interface unit to the digital filter, and filtering the sound source signal received from the input unit with the digital filter; And an amplifier that amplifies and outputs the filtered sound source signal output from the filter unit.

Description

Independent sound field forming apparatus for digital signage and digital signage system including the same{SEPARATE SOUND FIELD FORMING APPARATUS USED IN DIGITAL SIGNAGE AND DIGITAL SIGNAGE SYSTEM INCLUDING THE SAME}

The present invention relates to an apparatus for forming an independent sound field for digital signage and a digital signage system including the same, and more specifically, a specific area on the front side of the screen of digital signage that sounds related to content displayed on the screen of the digital signage. Independent sound field forming apparatus for digital signage that can be heard well in the digital signage system including the same.

In general, advertisement is a series of activities aimed at informing potential consumers of information and purchase methods for products and services. Recently, due to the rapid development of technology, various media such as newspapers and television media, for example, New media such as digital signage are emerging.

Digital signage is a combination of various IT technologies such as hardware, software, content, and network, and means a digital information display (DID) that can output various types of information such as still images and videos and advertisement data. do.

Digital signage is currently installed and operated in large buildings and businesses, such as terminals, government offices, bus stops, department stores, subways, airports, hotels, hospitals, etc., where people stay for a certain period of time, such as elevators, movie theaters, restaurants, shopping malls, and stores. The demand for digital signage continues to increase.

The initial form of digital signage consists of a digital signage display such as a PDP (Plasma Display Panel), LCD (Liquid Crystal Display), and LED (Light Emitting Diode), and stores pre-made information and advertisement data. Recently, attention has been paid to a network-type digital signage in which the advertisement providing apparatus transmits information and advertisement data through a communication network, or a digital signage receiving the received information and advertisement data through a communication network. Digital signage mainly provides pictures or videos. Recently, there is a demand to provide a predetermined sound associated with a photo or video along with the photo or video. In particular, in the case of a movie or game advertisement, there is a demand to provide a predetermined sound together in order to maximize information transmission.

However, since digital signage is mainly installed in public places with many floating populations, provision of a predetermined sound may cause noise pollution to people who are not interested in the advertisement.

In order to solve these problems, there has been an attempt to prevent sound from being heard only in a specific area in front of a digital signage and not well in other areas using a directional speaker or an ultrasonic speaker.

However, the directional speakers are hardware-based, and once installed in a specific place, it is difficult to re-adjust the direction or width of the sound, and it is difficult to design a directional speaker suitable for a place because the environment of the installed place is different. have. In addition, since the ultrasonic speaker consumes a lot of power and uses ultrasonic waves, sound quality is poor.

The problem to be solved by the embodiments of the present invention is that the sound is heard well in a specific area on the front side of the screen of the digital signage, and the sound is hardly heard in other areas or the noise is caused by back ground noise. Provided is an independent sound field forming apparatus for digital signage that can be buried to minimize interference, and a digital signage system including the same.

In addition, the present invention provides an independent sound field forming apparatus for digital signage capable of adjusting the size or/and position of a specific region where sound is well heard, and a digital signage system including the same.

An apparatus for forming an independent sound field for digital signage according to an embodiment includes an input unit that receives a sound source signal related to content displayed through a screen of a digital signage; An interface unit formed on a front side of the screen of the digital signage and controlling a bright zone, which is an area where sound is heard above a threshold; A filter unit including a digital filter, updating a filtering coefficient corresponding to a control signal from the interface unit to the digital filter, and filtering the sound source signal received from the input unit with the digital filter; And an amplifier that amplifies and outputs the filtered sound source signal output from the filter unit.

When an independent sound field forming apparatus for digital signage according to an embodiment of the present invention and a digital signage system including the same are used, sound is heard well in a specific area on the front side of the screen of the digital signage, and sound in other areas It has the advantage that it can be difficult to hear or the noise is buried in other ground noise (back ground noise) to minimize interference.

In addition, there is an advantage that can adjust the size or / and the position of a specific area where the sound is well heard.

1 and 2 are perspective views of a conventional digital signage.
3 is a block diagram of a digital signage system 10 including an independent sound field forming apparatus 100 according to an embodiment of the present invention.
4 is a perspective view of an example of the independent sound field forming apparatus 100 shown in FIG. 3.
6 is a block diagram of an independent sound field forming apparatus 100 illustrated in FIGS. 4 and 5.
7 to 8 are views illustrating a case where the independent sound field forming apparatus 100 including the speaker module shown in FIG. 4 is connected to the digital signage shown in FIG. 1.
9 is a view showing that the rotating member is further added in the example shown in FIG. 7.
10 to 11 are views for exemplarily explaining a method of forming filtering coefficients stored in the storage unit 645 of the filter unit 640 illustrated in FIG. 6.

For a detailed description of the present invention, which will be described later, reference is made to the accompanying drawings that illustrate specific embodiments in which the present invention may be practiced. These examples are described in detail enough to enable those skilled in the art to practice the present invention. It should be understood that the various embodiments of the invention are different, but need not be mutually exclusive. For example, the specific shapes, structures, and properties described herein may be implemented in other embodiments without departing from the spirit and scope of the invention in relation to one embodiment. In addition, it should be understood that the location or placement of individual components within each disclosed embodiment can be changed without departing from the spirit and scope of the invention. Therefore, the following detailed description is not intended to be taken in a limiting sense, and the scope of the present invention, if appropriately described, is limited only by the appended claims, along with all ranges equivalent to those claimed. In the drawings, similar reference numerals refer to the same or similar functions throughout several aspects.

1 and 2 are perspective views of a conventional digital signage.

The digital signage DS shown in FIG. 1 may visually provide one or a plurality of contents through a multivision function using a plurality of display modules. In addition, the digital signage DS' illustrated in FIG. 2 may visually provide predetermined content using one display module.

The independent sound field forming apparatus according to the embodiment of the present invention may be a device that can be connected to the digital signage (DS, DS') shown in FIGS. 1 and 2 through wired or wireless. Alternatively, the independent sound field forming apparatus according to the embodiment of the present invention is mounted on the inside or outside of the digital signage (DS, DS') shown in FIGS. 1 and 2 and integrally with the digital signage (DS, DS'). It may be configured.

The independent sound field forming apparatus according to the embodiment of the present invention may emit content provided through digital signage, for example, a sound related to a picture or a video.

Here, the independent sound field forming apparatus according to the embodiment of the present invention emits a predetermined sound, but makes the sound well to a person located in a specific area (or a bright zone) on the front side of the screen of the digital signage, and the specific area Others located in other areas (or dark zones) can make the sound inaudible.

In addition, the independent sound field forming apparatus according to the embodiment of the present invention can adjust the position and size (or range) of the specific region (or bright zone) without changing the hardware configuration of the independent sound field forming apparatus.

Hereinafter, an independent sound field forming apparatus according to an embodiment of the present invention will be described in detail with reference to the drawings.

3 is a block diagram of a digital signage system 10 including an independent sound field forming apparatus 100 according to an embodiment of the present invention.

Referring to FIG. 3, the digital signage system 10 according to an embodiment of the present invention may include an independent sound field forming apparatus 100, a digital signage 300 and a content providing apparatus 500.

The content providing apparatus 500 provides predetermined contents to the independent sound field forming apparatus 100 and the digital signage 300. Here, the predetermined content may be one or more.

The predetermined content may include visual information such as picture or video data and auditory information such as a sound source signal. The sound source signal may be a stereo sound signal or a mono sound signal. The stereo sound source signal includes at least two or more channel sound source signals. The two channel sound source signals may be a left channel sound source signal and a right channel sound source signal.

The content providing apparatus 500 may provide visual information of a predetermined content to the digital signage 300 and auditory information of the predetermined content to the independent sound field forming apparatus 100. The visual information and the auditory information may be provided to the independent sound field forming apparatus 100 and the digital signage 300 through wired or wireless communication, respectively.

The content providing device 500 receives predetermined content from the outside through wired or wireless, separates and processes visual information and auditory information from the received predetermined content, and provides auditory information to the independent sound field forming apparatus 100, digitally Visual information may be provided to the signage 300.

The independent sound field forming apparatus 100 may receive auditory information, that is, a sound source signal, from the content providing apparatus 500, and convert and output the provided sound source signal into sound (or sound waves).

The independent sound field forming apparatus 100 may form a predetermined sound field on the front side of the digital signage 300. Here, the sound field means a place where a medium transmits sound to a space where sound exists.

The sound field formed by the independent sound field forming apparatus 100 includes a bright zone (BZ) and a dark zone (DZ). Here, the bright zone (BZ) may be a region that is included in the independent sound field forming apparatus 100 or is output from an array speaker connected to the independent sound field forming apparatus 100 to a region where a sound is heard above a threshold, and a dark zone ( DZ) may be an area defocused to an area in which sound output from the array speaker is heard below a threshold.

The independent sound field forming apparatus 100 may adjust the position (or direction) and size (or range) of the bright zones BZ and the dark zones DZ. Here, the independent sound field forming apparatus 100 may adjust the position (or direction) and the size (or range) of the bright zone (BZ) and the dark zone (DZ) according to the user's selection. Hereinafter, with reference to FIGS. 4 to 6, the bright zone (BZ) and the dark zone (DZ) are formed, and the location and size (or range) of the bright zone (BZ) and the dark zone (DZ) can be adjusted independently The sound field forming apparatus 100 will be described in detail.

4 is a perspective view of an example of the independent sound field forming apparatus 100 shown in FIG. 3.

Referring to FIG. 4, the independent sound field forming apparatus 100 may include an output unit 110 through which sound is output, and an interface unit 130 capable of adjusting the location and size (or range) of the bright zone BZ. have.

Sound is output through the output unit 110 so that a predetermined sound field is formed toward the front side of the output unit 110.

The output unit 110 may include an array speaker. The array speaker may be embodied as at least one of a line array arranged in a straight rod shape and a round array structure arranged in a circular shape. The round array structure wraps around the user, and may be implemented in a circular shape, an oval shape, or the like. Through such a round array structure, it is possible to reproduce a more effective sound source centering on the user than the line array structure.

The interface unit 130 may be formed on the outer surface of the independent sound field forming apparatus 100 for ease of user selection. However, the present invention is not limited thereto, and the interface unit 130 may be disposed inside the independent sound field forming apparatus 100.

The interface unit 130 includes a first interface 131 for adjusting the size (or range) of the bright zone BZ, a second interface 133 for adjusting the position (or direction) of the bright zone BZ, and bright It may include a third interface 135 for adjusting the volume of the sound in the zone (BZ).

The first interface 131 may adjust the width of the sound or sound field emitted from the output unit 110 of the independent sound field forming apparatus 100, as shown in FIG. 5(a). The width may correspond to the size or range of the bright zone (BZ). The user may adjust the width of the sound or sound field emitted from the output unit 110 by adjusting the first interface 131 to be normal, wide, or narrow. In FIG. 4, the first interface 131 is illustrated as being configured in a switch form, but is not limited thereto. The first interface 131 may also be configured as a jog dial, button, or touch screen.

The second interface 133 may adjust the direction of the sound or sound field emitted from the output unit 110 of the independent sound field forming apparatus 100, as shown in FIG. 5(b). The direction may correspond to the location or direction of the bright zone BZ. The user may adjust the direction of the sound or sound field emitted from the output unit 110 by adjusting the second interface 133 as front, right, and left. The right or left side may be adjusted at a predetermined angle (eg, 30 degrees, -30 degrees) based on the forward direction. In FIG. 4, the second interface 133 is illustrated as being configured as a switch, but is not limited thereto, and the second interface 133 may also be configured as a jog dial, button, or touch screen.

The third interface 135 may adjust the volume of sound emitted from the output unit 110 of the independent sound field forming apparatus 100. More specifically, the sound volume in the bright zone (BZ) can be adjusted. In FIG. 4, the third interface 135 is illustrated as being configured in the form of a jog dial, but is not limited thereto, and the third interface 135 may also be configured as a switch, a button, and a touch screen.

Hereinafter, an internal block diagram of the independent sound field forming apparatus 100 illustrated in FIGS. 4 and 5 will be described in detail with reference to FIG. 6.

6 is a block diagram of an independent sound field forming apparatus 100 illustrated in FIGS. 4 and 5.

Referring to FIG. 6, an independent sound field forming apparatus 100 according to an embodiment of the present invention includes an input unit 601, an adder 610, an analog digital converter (ADC) 620, a demultiplexer 630, and a filter unit 640, a DAC (Digital Analog Converter, 650) and an amplifier (Amp, 660). Here, the independent sound field forming apparatus 100 may further include a speaker module (not shown).

One or more channel sound source signals are input to the input unit 601. When a mono channel sound source signal is input, the input unit 601 may be configured as one terminal. In addition, when a 2-channel stereo sound source signal is input, the input unit 601 may include two terminals. In addition, when a multi-channel sound source signal is input, the input unit 601 may include a plurality of terminals.

The summer 601 adds two or more channel sound source signals provided from the input unit 601. Here, when the input unit 601 is composed of one terminal, the summer 601 may be omitted.

The ADC 620 converts one analog sound source signal output from the summer 610 into a digital sound source signal.

The demultiplexer 630 distributes one digital sound source signal output from the ADC 620 to any one of a plurality of channels. Here, the demultiplexer 630 may distribute a digital sound source signal to any one of 8 channels. The demultiplexer 630 may also be referred to as a divider. For example, the demultiplexer 630 may be 8 channels.

The filter unit 640 may include a plurality of digital filters 641, a control unit 643, and a storage unit 645. The storage unit 645 stores a plurality of filtering coefficients in advance. The filtering coefficient may be, for example, a coefficient such that the ratio of the spatial average acoustic energy of the bright zone (BZ) and the spatial average acoustic energy of the dark zone (DZ) outside the bright zone (BZ) is maximized. The filtering coefficients have different values depending on the location (or direction) and size (or range) of the bright zone BZ.

The digital filter 641 may be an infinite impulse response filter (FIR filter). The digital filter 641 may be plural. The number of digital filters 641 may correspond to the number of a plurality of channels through which the demultiplexer 630 can distribute digital sound source signals. That is, each channel of the demultiplexer 630 may correspond to one digital filter 641.

The control unit 643 may receive a control signal output from the interface unit 130 and update the digital filter 641 based on the received control signal. The control unit 643 may receive the filtering coefficient corresponding to the control signal from the storage unit 645 and update the corresponding digital filter 641 by sending the received filtering coefficient to a predetermined digital filter 641.

Here, the control signal received by the control unit 643 from the interface unit 130 includes a first control signal from the first interface unit 131 and a second control signal from the second interface unit 133. The controller 643 may determine a filtering coefficient to request the storage unit 645 based on the first control signal and the second control signal, and receive the determined filtering coefficient from the storage unit 645.

The digital filter 641 filters the digital sound source signal provided through the demultiplexer 630 with the updated filtering coefficient to output the filtered sound source signal. Here, the filtered sound source signal is a sound source signal optimized for the bright zone (BZ).

The filtered sound source signal output from the digital filter 641 is input to the DAC 650. The DAC 650 converts the input filtered sound source signal to an analog sound source signal and outputs it.

The demultiplexer 630 and the filter unit 640 may be implemented with a field programmable gate array (FPGA).

The DAC 650 may have a plurality of channels, for example, a channel of the demultiplexer 630 or a channel corresponding to the number of digital filters 641. Specifically, the DAC 650 may be 8 channels.

The amplifier 660 amplifies the analog sound source signal output from the DAC 650. The amplifier 660 may be plural. Each amplifier 660 may receive an analog sound source signal from one or more DACs 650. The amplifier 660 may be a stereo amplifier that receives and amplifies two analog sound source signals. For example, four amplifiers 660 may be provided as stereo amplifiers.

The amplifier 660 may have an amplification gain adjusted according to a control signal provided from the interface 130. The volume (or amplitude) of sound output through the speaker module (not shown) may be adjusted according to the adjustment of the amplification degree. As a result, the volume (or amplitude) of the sound in the bright zone (BZ) can be adjusted.

The control signal provided to the amplifier 660 may be a control signal received from the third interface 135 of the interface unit 130.

The amplified sound source signal output from each amplifier 660 is output to the output unit 609, and the output unit 609 may be connected to a speaker module (not shown). The sound source signal amplified through the speaker module (not shown) is converted into sound waves and output. The speaker module (not shown) may be composed of one or multiple array speakers.

The speaker module (not shown) may not be included in the independent sound field forming apparatus 100. That is, the independent sound field forming apparatus 100 is configured separately from the speaker module (not shown), and the speaker module (not shown) is a sound source signal capable of forming a predetermined bright zone BZ from the independent sound field forming apparatus 100. You can receive and emit sound.

The independent sound field forming apparatus 100 according to an embodiment of the present invention converts a sound source signal input to the input unit 601 into a digital sound source signal, and provides a digital sound source signal from the interface unit 130 through the filter unit 640 It can filter with the updated filtering coefficient according to the control signal, convert the filtered sound source signal to an analog sound source signal, and amplify and output the converted analog sound source signal.

The independent sound field forming apparatus 100 according to the embodiment of the present invention filters the sound source signal through the filter unit 640, and filters the filtered sound source signal through the DAC 650, the amplifier 660, and a speaker (not shown). By outputting it, it is possible to form a predetermined bright zone BZ on the front side of the digital signage 300.

In addition, the independent sound field forming apparatus 100 according to the embodiment of the present invention can update the filtering coefficient of the digital filter 641 according to the control signal provided from the interface 130, and digitally update the filtering coefficient. The position (or direction) and the size (or range) of a given bright zone BZ that was formed on the front side of the signage 300 may be adjusted.

7 and 8 are diagrams illustrating a case in which the independent sound field forming apparatus 100 including the speaker module shown in FIG. 4 is connected to the digital signage shown in FIG. 1.

7 is an exemplary view showing that the independent sound field forming apparatus 100 forms a bright zone BZ in a specific area in front of the digital signage 300.

In FIG. 7, the independent sound field forming apparatus 100 is illustrated as being installed adjacent to the upper portion of the digital signage 300, but is not limited thereto. For example, the independent sound field forming apparatus 100 may be installed adjacent to the lower portion of the digital signage 300, or may be installed adjacent to one or both sides of the digital signage 300.

In addition, the independent sound field forming apparatus 100 may be installed at a predetermined distance from the digital signage 300. For example, the independent sound field forming apparatus 100 may be disposed to face each other at a predetermined distance from the front of the digital signage 300, or may be disposed over a distance from the front of the digital signage 300. .

8 is an exemplary view showing that the independent sound field forming apparatus 100 forms a newly adjusted bright zone BZ' when the interface unit is adjusted by the user.

Compared with the bright zone BZ shown in FIG. 7, the newly adjusted bright zone BZ' has been moved to the right a predetermined distance, and the size of the zone has become larger.

As described above, the independent sound field forming apparatus 100 according to the embodiment of the present invention does not change the internal hardware configurations of the independent sound field forming apparatus 100, and the location of the bright zone is only controlled by the interface unit 130 by the user. (Or direction) and size (or range) can be adjusted.

Meanwhile, the position of the bright zone may be adjusted by physically or mechanically adjusting the independent sound field forming apparatus 100 itself.

For example, as illustrated in FIG. 9, the independent sound field forming apparatus 100 may be rotated using a rotating member (not shown) that can mechanically rotate the independent sound field forming apparatus 100. When the independent sound field forming apparatus 100 is rotated mechanically, a new bright zone BZ'' can be formed. It can be confirmed that the new bright zone BZ'' was moved upward compared to the bright zone BZ shown in FIG. 7.

Meanwhile, FIGS. 10 to 11 are views for explaining a method of forming filtering coefficients stored in the storage unit 645 of the filter unit 640 illustrated in FIG. 6.

In FIG. 10, for convenience of explanation and understanding, a sound space for measuring a transfer function, a speaker 1100, a microphone 2000, and the like are schematically illustrated, but a larger number of microphones 2000 and a speaker 1100 Can be used to measure the transfer function.

The plurality of speakers 1100 and 1120 of FIG. 10 may be included in a speaker of the independent sound field forming apparatus 100 according to an embodiment of the present invention or a speaker module connected to the independent sound field forming apparatus 100. The plurality of speakers 1110 and 1120 may constitute a speaker array. For example, 30 channel microphones 2000 of 6X5 array spaced at 4 cm intervals and a plurality of speakers 1100 and 1120 having independent channels may be generated in independent sound fields. Further, the measurement of the transfer function may be performed in a plurality of regions within a predetermined space. However, this is only an example, and the setting system may be configured in various ways according to the size of the space and the structure of the space.

Referring back to FIG. 10, a first speaker array 1110 and a second speaker array 1120 functioning as sound sources at arbitrary positions are configured in an acoustic space (here, corresponding to a predetermined space). Here, the first speaker array 1110 means at least one speaker outputting a first sound source signal, and the second speaker array 1120 means at least one speaker outputting a second sound source signal.

The first speaker array 1110 and the second speaker array 1120 are not included in the areas of the Bright Zone (hereinafter,'BZ') and the Dark Zone (hereinafter,'DZ'), but are not limited thereto. Does not work.

In the description of FIG. 10, the bright zone BZ may be an area in which sound output from the first speaker array 1110 and the second speaker array 1120 is focused to an area where a sound is heard above a threshold, and the dark zone DZ ) May be an area defocused to an area in which sounds output from the first speaker array 1110 and the second speaker array 1120 are heard below a threshold. That is, since the distinction between the bright zone (BZ) and the dark zone (DZ) is based on the contrast of the sound pressure level, and more specifically, the contrast of the spatial average acoustic energy, the dark zone (DZ) region can be controlled so that no sound is heard. It may be, but may be controlled to detect a small sound.

)에서의 음압(

, 마이크로폰(2000)에 의하여 감지되는 신호)은 수학식 1과 같이 표현할 수 있다.On the other hand, any point created by the first sound source signal generated from the first speaker array 1110 and the second sound source signal generated from the second speaker array 1120 (

Sound pressure at)

, The signal sensed by the microphone 2000 may be expressed as Equation (1).

은 공간상의 j번째 지점이고,

은 i번째 음원 신호(제 1 음원 신호 또는 제 2 음원 신호에 포함되는)의 위치를 의미한다. 그리고

는

과

사이의 관계를 표현해주는 전달 함수이다. 여기서 전달 함수는 수학적인 모델로 정의하거나 실제 측정을 통해서 쉽게 얻을 수 있다. 수학식 1을 두 개의 지점의 경우에 대해 행렬의 형태로 표현하면 수학식 2와 같이 표현할 수 있다. here

Is the jth point in space,

Denotes the position of the i-th sound source signal (included in the first sound source signal or the second sound source signal). And

The

and

It is a transfer function that expresses the relationship between them. Here, the transfer function can be defined by a mathematical model or easily obtained through actual measurement. When Equation 1 is expressed in the form of a matrix for the case of two points, it can be expressed as Equation 2.

Similarly, the determinant expression for the first bright zone (BZ1), the second bright zone (BZ2), the dark zone (DZ), and the entire acoustic region (TZ) including the two regions described above is expressed by Equation 3 to Equation Same as 5. Subscripts b, d, and t in Equations 3 to 5 denote a bright zone (BZ), a dark zone (DZ), and an entire acoustic region (TZ), respectively.

Next, a variable representing space is determined. As the variable, it is defined as a spatial average acoustic energy, and can be expressed as Equation (6).

The reason for setting the spatial average acoustic energy as a representative variable of space is that it is difficult to express the acoustic characteristics inside a certain region by the sound pressure levels of each point alone. That is, the spatial average acoustic potential energy of the bright zone (BZ), the spatial average acoustic potential energy of the dark zone (DZ), and the spatial average acoustic potential energy of the entire acoustic region TZ may be defined as the sound pressure level of each region. have.

은 정의된 영역에서의 각 음원이 만들어내는 간섭정도를 나타내는 상관행렬로 정의된다. 그리고 2라는 숫자는 수학식 2에서의 마이크로폰(2000)의 개수를 의미한다. 이해의 편의를 위해서 간단한 경우에 대하여 표현한 것이지만, 실제로는 어떤 정의된 영역 내부에 포함되어있는 마이크로폰의 개수를 의미한다. 즉, 30개의 마이크로폰이 이용되는 경우라면, 2라는 숫자가 30으로 바뀔 것이다. 이러한 논리로 정의된 브라이트존(BZ)과 다크존(DZ)에 대한 공간평균음향에너지를 표현할 수 있다. Matrix in equation (6)

Is defined as a correlation matrix representing the degree of interference produced by each sound source in the defined region. And the number 2 means the number of microphones 2000 in Equation (2). For convenience of understanding, it is expressed as a simple case, but actually means the number of microphones included in a defined area. That is, if 30 microphones are used, the number 2 will change to 30. The spatial average acoustic energy for bright zone (BZ) and dark zone (DZ) defined by this logic can be expressed.

Next, a process of deriving a first sound source signal and a second sound source signal required to obtain a required control effect using sound pressure levels in each region defined in Equations 7 to 9 will be described for each case. .

One. In Bright Zone (BZ) Determination of the sound source signal that maximizes the contrast between the sound pressure level and the total size of the input

The total size of the input is defined as the sum of the absolute value of the complex size of the first sound source signal and the absolute value of the complex size of the second sound source signal, which can be referred to as the total size of control effort. The total size of the input is expressed by the following equation (10).

은 입력의 총 크기, 즉 제어 노력을 공간평균음향에너지의 차원(dimension)으로 변화시키는 정규화 상수이다.here,

Is the normalization constant that changes the total size of the input, that is, the control effort into the dimension of the spatial average acoustic energy.

Now, the contrast between the sound pressure level in the bright zone (BZ) and the total size of the input is expressed by the following Equation 11 using Equations 7 and 10, which is defined as “acoustic brightness”.

Therefore, determining the sound source signal that maximizes the contrast between the sound pressure level in the bright zone BZ and the total size of the input is a problem of obtaining a sound source signal that maximizes the value of α in Equation (11).

Equation 11 may be mathematically formulated as a problem that maximizes the Rayleigh quotient, which is expressed as Equation 12 below.

As shown in Equation 12, obtaining a sound source signal that maximizes the value of α is the same as obtaining the maximum eigenvalue of the generalized eigenvalue problem. Then, the eigenvectors corresponding to the maximum eigenvalues are the first sound source signal and the second sound source signal.

2. Determining the input signal that maximizes the contrast between bright zone (BZ) and dark zone (DZ)

Consider the input signal of the sound source that maximizes the contrast between the sound pressure level of the bright zone (BZ) and the sound pressure level of the dark zone (DZ). As in case 1, when the sound pressure level of the bright zone (BZ) for the dark zone (DZ) is mathematically expressed, it can be expressed as in Equation 13, which is defined as “acoustic contrast 1”.

Equation 13 can also be formulated as a problem that maximizes the Rayleigh quotient β, and is the same as the maximum eigenvalue and problem of the generalized eigenvalue problem as shown in Equation (14). The eigenvectors corresponding to the maximum eigenvalues are the first sound source signal and the second sound source signal.

Therefore, the above-described method uses a method of obtaining an optimal sound source control signal by grasping all of the transfer functions, compared to the conventional methods that reflect the relationship between the listener and the sound source in a limited form.

Therefore, unlike the active noise control that merely reduces the sound pressure level, the above-described method makes it possible to increase the relative difference in sound pressure level for each space. That is, it is possible to perform a control that increases not only the size of the sound pressure level corresponding to the acoustic brightness, but also increases the acoustic contrast between two different spaces.

3. Bright zone (BZ) and Total acoustic area ( TZ ) Determines the input signal that maximizes the contrast of the sound pressure level

The sound source input signal that maximizes the contrast of the sound pressure level of the bright zone (BZ) and the entire sound area (TZ) will be dealt with. As in the case of 2., the sound pressure level of the entire acoustic region TZ for the dark zone DZ can be expressed as in Equation 15, which is defined as "acoustic contrast 2".

를 최대로 하는 문제로 정식화할 수 있으며, 수학식 16에서 보는 바와 같이 일반화된 고유치문제의 최대 고유치와 문제와 동일하다. 그리고 최대 고유치에 해당하는 고유벡터가 제1 음원 신호와 제2 음원 신호가 된다.Equation 15 is the same for Rayleigh quotient.

It can be formulated as a problem that maximizes, and is the same as the maximum eigenvalue and the problem of the generalized eigenvalue problem as shown in Equation (16). The eigenvectors corresponding to the maximum eigenvalues are the first sound source signal and the second sound source signal.

4. A method for providing an independent acoustic environment to multiple bright zones (BZ)

A method for providing an independent acoustic environment to a plurality of bright zones (BZ) can be described in three ways.

[Method 1] In the first bright zone BZ1, the ratio of the sum of the spatial average acoustic energy of the first sound source signal and the energy of the first sound source signal is maximized, and the second bright zone BZ2 has a second When the ratio of the sum of the space average acoustic energy and the energy of the second sound source signal by the sound source signal is maximized

In this case, the input signal is differently derived for each bright zone BZ1, BZ2. This can be expressed as the following equation.

[Method 2] In the first bright zone (BZ1), the ratio of the spatial average acoustic energy by the first sound source signal and the spatial average acoustic energy in the rest of the area except for the first bright zone (BZ1) is maximized. 2 When the ratio of the spatial average acoustic energy due to the second sound source signal to the bright zone (BZ2) and the spatial average acoustic energy in the remaining regions except for the second bright zone (BZ2) are maximized

In this case, the input signal is differently derived for each bright zone BZ. This can be expressed as the following equation.

[Method 3] When there are a large number of bright zones (BZ), the first bright zone (BZ1) has a spatial average acoustic energy in the entire region including a first average sound source signal and a first bright zone (BZ1). At the same time, the ratio of the space average acoustic energy by the second sound source signal to the second bright zone (BZ2) and the space average acoustic energy in the entire area including the second bright zone (BZ2) are maximized. If

In this case, the input signal is differently derived for each bright zone BZ. This can be expressed as the following equation.

In the case of the above three methods, the input signals are differently derived for each bright zone (BZ), and the input signals entering the first and second sound sources are commonly represented by Equation (23).

In this case, a plurality of independent acoustic environments in which the reproduction sound by the first input signal is present in the first bright zone BZ1 and the reproduction sound by the second input signal is present in the second bright zone BZ2 can be created. .

In summary, the above-described method uses a method of acquiring an optimal sound source signal by grasping all the transfer functions, compared to the conventional methods reflecting the relationship between the listener and the sound source in a limited form.

Therefore, the above-described method increases the relative difference in sound pressure level for each region in the acoustic space, unlike active noise control that simply reduces the sound pressure level. That is, the above-described method is to perform a control that increases not only the magnitude of the sound pressure level corresponding to the acoustic brightness, but also increases the acoustic contrast between two different areas.

The method of forming the bright zone (BZ) and the dark zone (DZ) will be described in more detail with reference to FIG. 11 further.

The system for measuring the transfer function to set the bright zone (BZ), as shown in Figure 11, the speaker module 300, a microphone 2000, a signal generator 3000, a signal analyzer 4000 It can contain.

The speaker module 300 may include a plurality of speakers 1110 and 1120 generating a plurality of sound source signals and a multi-channel amplifier 1200 capable of driving the plurality of speakers.

The signal generator 3000 may include a multi-channel signal generator 3100 capable of providing synchronized individual sound source signals to the respective speakers 1100 and 1120 through the multi-channel amplifier 1200.

The signal analysis unit 4000 measures the transfer function between the sound signal (q) generated by the plurality of speakers 1110 and 1120 and the sound signal (p) detected by the microphone 2000, and determines the appropriate sound source signal. It may include a multi-channel signal analyzer 4100 for transmitting information to the multi-channel signal generator 3100 of the signal generator 3000.

를 최대로 하거나(음향밝기 제어), 수학식 19, 20의 음향대조 1

을 최대로 하거나(음향대조 1 제어), 수학식 21, 22의 음향대조 2

를 최대로 하는(음향대조 2 제어) 음원 신호를 의미할 수 있다.Here, a suitable sound source signal is the acoustic brightness of Equations 17 and 18 above.

To maximum (acoustic brightness control), Equation 19, 20 sound contrast 1

To maximum (acoustic contrast 1 control), or acoustic contrast 2 of equations 21 and 22

It may mean a sound source signal that maximizes (controls the acoustic contrast 2).

Referring to FIG. 11, the signal analysis unit 4000 measures a transfer function between the sound source signal q generated in the speaker module 300 and the sound signal p detected by the microphone 2000 (step S1). In measuring the transfer function, since a large amount of measurement is required according to the number of the speaker 1100 and the number of the microphones 2000, it is convenient to measure the transfer function in the following simple method that is commonly used. You can.

In this simple method, after inputting uncorrelated white noise as a sound source signal (q) input to a plurality of speakers (1100), the sound signal (p) detected by each microphone (2000) of each sound source By separating the contribution, the transfer function between the sound source signal q of the speaker module 300 and the sound signal p of the microphone 2000 is measured by one measurement.

Next, the signal analysis unit 4000 determines a suitable sound source signal using the transfer function measured in step S1, and transmits the determined suitable sound source signal to the signal generation unit 3000 (step S2).

Here, although a single frequency is described, if it is composed of a plurality of frequencies, it may be understood that the sound source signals for each frequency are determined. Further, the sound source signal determined here may function as a filtering coefficient for filtering the original sound signal (any sound to be heard in the bright zone BZ) in step S3 described later.

Next, the signal generation unit 3000 filters the original sound signal based on the information received from the signal analysis unit 4000 with the determined sound source signal (or filtering coefficient) determined in step S2, and then transmits it to the bright zone BZ. The optimized sound source signal (filtered sound source signal) is generated, and the optimized sound source signal is transmitted to the speaker module 300 (step S3).

Next, the speaker module 300 may output the optimized sound source signal received from the signal generator 3000 through the bright zone (step S4).

Acoustic brightness control is to have the maximum sound pressure level in the bright zone (BZ) for the same input size, so it is more useful when the size of the input cannot be increased, for example, when the size of the input is limited.

However, the acoustic brightness control has a disadvantage that the sound is relatively louder than the acoustic control 1 control and the acoustic control 2 control in an area other than the bright zone (BZ). Therefore, it is more efficient and effective in the case where the sound is not too small in a region other than the bright zone (BZ).

The acoustic control 1 control and the acoustic control 2 control show better bright zone (BZ) generation results than the acoustic brightness control unless the size of the input is excessively limited. In addition, since the sound control 1 control and the sound control 2 control have a very small sound in areas other than the bright zone (BZ), the size of the sound reproduction device is better than the sound brightness control in all cases of small, medium, and large Do.

The features, structures, and effects described in the above embodiments are included in one embodiment of the present invention, and are not necessarily limited to only one embodiment. Furthermore, features, structures, effects, and the like exemplified in each embodiment may be combined or modified for other embodiments by a person having ordinary knowledge in the field to which the embodiments belong. Therefore, the contents related to such combinations and modifications should be interpreted as being included in the scope of the present invention.

In addition, although the embodiments have been mainly described above, these are merely examples and do not limit the present invention, and those skilled in the art to which the present invention pertains are exemplified above without departing from the essential characteristics of this embodiment. It will be appreciated that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be implemented by modification. And differences related to these modifications and applications should be construed as being included in the scope of the invention defined in the appended claims.

100: independent sound field forming device
300: digital signage
500: content providing device

Claims (10)

An input unit that receives a sound source signal related to the content displayed through the screen of the digital signage;
An interface unit formed on a front side of the screen of the digital signage and controlling a bright zone, which is an area where sound is heard above a threshold;
A filter unit including a digital filter, updating a filtering coefficient corresponding to a control signal from the interface unit to the digital filter, and filtering the sound source signal received from the input unit with the digital filter; And
An amplifier for amplifying and outputting the filtered sound source signal output from the filter unit;
Including,
The filter unit further includes a storage unit storing a plurality of the filtering coefficients, a control unit receiving the control signal output from the interface unit, and updating the digital filter based on the received control signal,
The control unit receives the filtering coefficient corresponding to the received control signal from the storage unit, and sends the received filtering coefficient to the digital filter to update the digital filter,
The filter unit outputs the filtered sound source signal by filtering the sound source signal received from the input unit with the updated digital filter, an independent sound field forming apparatus for digital signage.
According to claim 1, wherein the interface unit,
A first interface unit outputting a first control signal for adjusting the size of the bright zone to the control unit of the filter unit; And
And a second interface unit configured to output a second control signal for adjusting the position of the bright zone to the control unit of the filter unit.
According to claim 2, The interface unit,
Further comprising a third interface unit for outputting a third control signal for adjusting the volume of the sound heard in the bright zone to the amplifier;
The amplifier controls the amplification degree of the filtered sound source signal according to the third control signal, and amplifies and outputs the filtered sound source signal according to the adjusted amplification degree, an independent sound field forming apparatus for digital signage.
According to claim 1,
An ADC that converts the sound source signal received from the input unit into a digital sound source signal; And
Includes; a demultiplexer for distributing the digital sound signal to any one of a plurality of channels;
The demultiplexer outputs the digital sound source signal to the digital filter of the filter unit, an independent sound field forming apparatus for digital signage.
The method of claim 4,
The input unit includes a plurality of input terminals to which a plurality of channel sound source signals are respectively input,
And a summator for summing the plurality of channel sound source signals input through the plurality of input terminals.
According to claim 1,
And a DAC that is connected between the filter unit and the amplifier and converts the filtered sound source signal output from the filter unit to an analog sound source signal.
According to claim 1,
Independent sound field forming apparatus for digital signage further comprising a; speaker module for outputting the sound source signal output from the amplifier as sound.
An independent sound field forming apparatus for digital signage according to any one of claims 1 to 7;
The digital signage; And
A content providing device that receives the content, provides the sound source signal related to the content to the independent sound field forming device, and provides the content to the digital signage;
Including, digital signage system.
The method of claim 8,
A rotating member equipped with the independent sound field forming apparatus and rotating the independent sound field forming apparatus to change the position of the bright zone; The digital signage system further comprising.
The method of claim 8,
The independent sound field forming apparatus is integral with the digital signage, a digital signage system.

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