JP5941373B2 - Speaker array driving apparatus and speaker array driving method - Google Patents
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Description
この発明は、スピーカアレイ駆動装置およびスピーカアレイ駆動方法に関する。 The present invention relates to a speaker array driving apparatus and a speaker array driving method.
将来、スーパーハイビジョンを放送する場合には、スーパーハイビジョン音響である２２．２チャネル音響を家庭でどのように再生するかが課題となる。その１つの方法として、映像ディスプレイと一体化したＷＦＳ（Wave Field Synthesis）対応のスピーカアレイによる再生方式がある。この方式は、映像ディスプレイの周りに備えたスピーカアレイにより、２２．２チャネル音響の前方１１チャネルの位置に、その仮想音像を形成するものである。ここで、ＷＦＳは、直線状のスピーカアレイや、音場を取り囲む直線上あるいは曲線状アレイによって音の場を再現する方法であり、５．１チャネルのスピーカアレイ再生技術などが実用化されている（例えば、非特許文献１参照）。 In the future, when broadcasting Super Hi-Vision, the issue is how to reproduce 22.2 channel sound, which is Super Hi-Vision sound, at home. As one of the methods, there is a reproduction method using a speaker array compatible with WFS (Wave Field Synthesis) integrated with a video display. In this system, a virtual sound image is formed at the position of 11 channels ahead of 22.2 channel sound by a speaker array provided around the video display. Here, WFS is a method of reproducing a sound field by using a linear speaker array, a straight line surrounding a sound field or a curved array, and 5.1 channel speaker array reproduction technology has been put into practical use. (For example, refer nonpatent literature 1).
映像ディスプレイの周りに配した窓枠状のスピーカアレイの場合には、特に映像ディスプレイの中央に対応したチャネルへの仮想音像を形成する場合に、その近傍に実際のスピーカが存在せず、スピーカからの距離も遠いため、仮想音像からの音波の合成波面や音の周波数特性が損なわれたりすることがあり、特に２２．２チャネル音響を映像ディスプレイ一体型のスピーカアレイで再生する場合の問題となっていた。 In the case of a window frame speaker array arranged around the video display, there is no actual speaker in the vicinity of the speaker, especially when a virtual sound image is formed on a channel corresponding to the center of the video display. Therefore, the synthesized wavefront of the sound wave from the virtual sound image and the frequency characteristics of the sound may be impaired, which is particularly a problem when reproducing 22.2 channel sound with a speaker array integrated with a video display. It was.
したがって、かかる点に鑑みてなされた本発明の目的は、映像ディスプレイの周囲に配置可能なスピーカアレイにおいて、実際のスピーカが配置されていない仮想音像からの音波の合成波面や音の周波数特性を改善可能なスピーカアレイ駆動装置およびスピーカアレイ駆動方法を提供することにある。 Accordingly, an object of the present invention made in view of such a point is to improve a synthetic wavefront of sound waves and a frequency characteristic of sound from a virtual sound image in which no actual speaker is arranged in a speaker array that can be arranged around a video display. An object is to provide a speaker array driving device and a speaker array driving method.
上述した諸課題を解決すべく、本発明に係るスピーカアレイ駆動装置は、複数のスピーカを有するスピーカアレイと、仮想音像位置と前記スピーカアレイ中のスピーカの位置に基づき前記スピーカアレイの駆動信号を計算する駆動信号計算部と、前記駆動信号に対して重み係数を乗算して重み付け駆動信号を生成する重み係数乗算部と、前記重み付け駆動信号により前記スピーカアレイを駆動することにより受音点で得られる周波数特性を計算する周波数特性計算部と、前記周波数特性の非平坦度を計算する周波数特性非平坦度計算部と、前記重み付け駆動信号を前記スピーカアレイにより再生した際の前記受音点を含む受音エリアでの音波の合成波面の乱れ度を計算する合成波面乱れ度計算部と、前記周波数特性の非平坦度と前記合成波面の乱れ度とを最小化するように前記重み係数を計算する重み係数計算部と、を備える。 In order to solve the above-described problems, a speaker array driving apparatus according to the present invention calculates a speaker array drive signal based on a speaker array having a plurality of speakers, a virtual sound image position, and a speaker position in the speaker array. Obtained at a sound receiving point by driving the speaker array with the weighted drive signal, a drive signal calculating unit for generating the weighted drive signal by multiplying the drive signal with a weighting factor A frequency characteristic calculation unit that calculates frequency characteristics; a frequency characteristic non-flatness calculation unit that calculates non-flatness of the frequency characteristic; and a receiving point that includes the sound receiving point when the weighted drive signal is reproduced by the speaker array. A synthetic wavefront turbulence degree calculating unit for calculating a turbulence degree of a synthetic wavefront of a sound wave in a sound area; and non-flatness of the frequency characteristic and the synthetic wavefront It includes a weighting factor calculator for calculating the weighting coefficients so as to minimize the disturbance degree, the.
また、前記周波数特性非平坦度計算部は、前記周波数特性を多項式近似し、当該多項式の係数の二乗和に基づいて前記周波数特性の非平坦度を計算する、ことが好ましい。 The frequency characteristic non-flatness calculating unit preferably approximates the frequency characteristic by a polynomial and calculates the non-flatness of the frequency characteristic based on a square sum of the coefficients of the polynomial.
また、前記合成波面乱れ度計算部は、前記仮想音像位置に実音像を置いた場合の音圧と、前記重み付け駆動信号を前記スピーカアレイにより再生した際の音圧との差分を、前記受音エリアにおいて空間的に積分することにより、前記合成波面の乱れ度を計算する、ことが好ましい。 Further, the synthetic wavefront disturbance degree calculator calculates a difference between a sound pressure when a real sound image is placed at the virtual sound image position and a sound pressure when the weighted drive signal is reproduced by the speaker array. It is preferable to calculate the degree of disturbance of the combined wavefront by integrating spatially in the area.
さらに、本発明に係るスピーカアレイ駆動方法は、複数のスピーカを有するスピーカアレイを備えるスピーカアレイ駆動装置におけるスピーカアレイ駆動方法であって、前記スピーカアレイ駆動装置による処理手順が、仮想音像位置と前記スピーカアレイ中のスピーカの位置に基づき前記スピーカアレイの駆動信号を計算するステップと、前記駆動信号に対して重み係数を乗算して重み付け駆動信号を生成するステップと、前記重み付け駆動信号により前記スピーカアレイを駆動することにより受音点で得られる周波数特性を計算するステップと、前記周波数特性の非平坦度を計算するステップと、前記重み付け駆動信号を前記スピーカアレイにより再生した際の前記受音点を含む受音エリアでの音波の合成波面の乱れ度を計算するステップと、前記周波数特性の非平坦度と前記合成波面の乱れ度とを最小化するように前記重み係数を計算するステップと、を備える。 Furthermore, the speaker array driving method according to the present invention is a speaker array driving method in a speaker array driving apparatus including a speaker array having a plurality of speakers, and the processing procedure by the speaker array driving apparatus includes a virtual sound image position and the speaker. Calculating a drive signal for the speaker array based on the position of the speaker in the array; generating a weighted drive signal by multiplying the drive signal by a weighting factor; and A step of calculating a frequency characteristic obtained at a sound receiving point by driving; a step of calculating a non-flatness of the frequency characteristic; and the sound receiving point when the weighted drive signal is reproduced by the speaker array. Calculating the degree of disturbance of the combined wavefront of the sound wave in the receiving area , And a step of calculating the weighting coefficients so as to minimize the disturbance of non-flatness and the combined wavefront of the frequency characteristic.
本発明に係るスピーカアレイ駆動装置およびスピーカアレイ駆動方法によれば、映像ディスプレイの周囲に配置可能なスピーカアレイにおいて、実際のスピーカが配置されていない仮想音像からの音波の合成波面や音の周波数特性を改善することができる。 According to the speaker array driving apparatus and the speaker array driving method according to the present invention, in the speaker array that can be arranged around the video display, the synthesized wavefront of sound waves from the virtual sound image in which no actual speaker is arranged and the frequency characteristics of the sound Can be improved.
以降、諸図面を参照しながら、本発明の実施態様を詳細に説明する。ここで、以下の説明においては、スピーカアレイに入力される駆動信号として、スーパーハイビジョン音響である２２．２チャネル音響を例に説明を行うが、本発明は２２．２チャネル音響のみに限定されるものではない点に留意されたい。 Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Here, in the following description, a 22.2 channel sound that is a super high-definition sound will be described as an example of a drive signal input to the speaker array, but the present invention is limited to only a 22.2 channel sound. Note that it is not a thing.
図１は、本発明の一実施形態に係るスピーカアレイ駆動装置１のスピーカアレイ配置を示す図である。図示の通り、スピーカアレイ駆動装置１のスピーカアレイ９０の各スピーカは、表示部ＤＩＳの周囲に配置されている。以降の説明において、スピーカアレイ駆動装置１の水平方向をｘ軸、垂直方向をｙ軸、光軸方向をｚ軸とし、表示部ＤＩＳの中央を原点とする座標系を用いて説明を行う。 FIG. 1 is a diagram showing a speaker array arrangement of a speaker array driving apparatus 1 according to an embodiment of the present invention. As illustrated, each speaker of the speaker array 90 of the speaker array driving apparatus 1 is arranged around the display unit DIS. In the following description, the speaker array driving apparatus 1 will be described using a coordinate system in which the horizontal direction is the x axis, the vertical direction is the y axis, the optical axis direction is the z axis, and the center of the display unit DIS is the origin.
ここで、２２．２チャネル音響は、視聴者より高い位置に配置された上層の９チャネルと、視聴者の耳の高さの位置に配置された中層の１０チャネルと、視聴者より低い位置に配置された下層の３チャネルと、低音用ＬＦＥの２チャネル（０．２チャネル）とから構成される。２２．２チャネル音響のうち、視聴者の前方の１１チャネルは、上層の３ｃｈ、中層の５ｃｈ、および下層の３ｃｈから構成される。 Here, the 22.2 channel sound is in the upper 9 channels arranged higher than the viewer, the middle 10 channels arranged at the height of the viewer's ears, and lower than the viewer. It is composed of three lower-layer channels and two low-frequency LFE channels (0.2 channels). Among the 22.2 channel sounds, 11 channels in front of the viewer are composed of 3 ch of the upper layer, 5 ch of the middle layer, and 3 ch of the lower layer.
図２は、２２．２チャネル音響の前方１１チャネルの位置を示す図である。表示部ＤＩＳの上辺にはＴｐＦＬ、ＴｐＦＣ、ＴｐＦＲの上層３チャネル、表示部ＤＩＳの垂直方向中央にはＦＬ、ＦＬｃ、ＦＣ、ＦＲｃ、ＦＲの中層５チャネル、表示部ＤＩＳの下辺にはＢｔＦＬ、ＢｔＦＣ、ＢｔＦＲの下層３チャネルが配置されている。特に、中層５チャネルのうち、ＦＬｃ、ＦＣ、ＦＲｃの３チャネルは表示部ＤＩＳ内（スピーカが存在しない領域）に位置しており、実際のスピーカが存在しないチャネルとなっている。 FIG. 2 is a diagram illustrating the positions of the front 11 channels of 22.2 channel sound. The upper side of the display unit DIS is the upper three channels of TpFL, TpFC, TpFR, the center of the display unit DIS is the middle layer of FL, FLc, FC, FRc, FR, and the lower layer of the display unit DIS is BtFL, BtFC. , BtFR lower 3 channels are arranged. In particular, among the five channels of the middle layer, three channels of FLc, FC, and FRc are located in the display unit DIS (region where no speaker is present), and are channels in which no actual speaker is present.
ここで、図１に示すスピーカアレイ９０を駆動する方法として、第１種レイリー積分が知られている。スピーカアレイ９０中のスピーカ位置をｒ（ｒ＝（ｘ，ｙ，ｚ））、形成すべき仮想音像位置をｒｓ（ｒｓ＝（ｘｓ，ｙｓ，ｚｓ））とすると、第１種レイリー積分によるスピーカの駆動信号ｑｒ（ｔ）は、式（１）により計算することができる。ここでｃは音速を表し、Ｓ（ｔ）は２２．２チャネル音響の各チャネルの時刻ｔにおける入力信号を表す関数である。 Here, as a method of driving the speaker array 90 shown in FIG. 1, the first type Rayleigh integration is known. The speaker positions in the speaker array 90 r (r = (x, y, z)), a virtual sound image position for forming r s (r s = (x s, y s, z s)) When, first The loudspeaker drive signal q r (t) by seed Rayleigh integration can be calculated by the equation (1). Here, c represents the speed of sound, and S (t) is a function representing an input signal at time t of each channel of 22.2 channel sound.
図３は、式（１）の駆動信号のシミュレーション環境を示す図である。本シミュレーションにおけるスピーカアレイ９０では、表示部ＤＩＳの周りの横１．５８ｍ、縦１．０ｍのフレーム上に、直径４．５ｃｍの実スピーカが６０個配置されている。仮想音源からは１ｋＨｚ正弦波が放射されるものとし、１ｋＨｚ正弦波の合成波面と、仮想音源から聴取位置（ｘ，ｙ，ｚ）＝（０，０，１）までの伝達関数の周波数特性について評価を行なった。図４は、従来方式である式（１）を用いて、２２．２チャネル音響のＦＣチャネルの位置（ｘｓ，ｙｓ，ｚｓ）＝（０，０，０．０５）に仮想音像を形成した場合のシミュレーション結果を示す図である。表示部ＤＩＳ中央に位置するＦＣチャネルには、スピーカアレイ９０（実スピーカ）が存在しないため、合成波面や周波数特性ともに乱れが見られ、特に周波数特性の乱れは顕著である。このように、実スピーカが存在しない位置での仮想音像は、音色が大きく損なわれることが予想される。 FIG. 3 is a diagram illustrating a simulation environment of the drive signal of Expression (1). In the speaker array 90 in this simulation, 60 real speakers having a diameter of 4.5 cm are arranged on a frame having a width of 1.58 m and a length of 1.0 m around the display unit DIS. It is assumed that a 1 kHz sine wave is radiated from the virtual sound source, and the frequency characteristic of the transfer function from the virtual sound source to the listening position (x, y, z) = (0, 0, 1) is assumed to be a 1 kHz sine wave. Evaluation was performed. FIG. 4 shows a virtual sound image at the position (x s , y s , z s ) = (0, 0, 0.05) of the 22.2 channel acoustic FC channel using the conventional method (1). It is a figure which shows the simulation result at the time of forming. Since there is no speaker array 90 (real speaker) in the FC channel located at the center of the display unit DIS, both the composite wavefront and the frequency characteristics are disturbed, and the frequency characteristics are particularly disturbed. Thus, it is expected that the timbre of the virtual sound image at a position where no real speaker is present is greatly impaired.
ここで、スピーカアレイ９０によって安定した仮想音像を形成するためには、仮想音像位置に実音像を置いた場合に得られる周波数特性及び合成波面を、スピーカアレイ９０による再生で実現すれば良い。このため、本発明に係るスピーカアレイ駆動装置１は、式（１）に示す駆動信号に対して、スピーカアレイ再生による合成波面の乱れや、周波数特性の非平坦度を考慮した重みを乗算し、良好な合成波面及び周波数特性を実現するものである。 Here, in order to form a stable virtual sound image by the speaker array 90, the frequency characteristics and the synthesized wavefront obtained when the real sound image is placed at the virtual sound image position may be realized by reproduction by the speaker array 90. For this reason, the speaker array driving apparatus 1 according to the present invention multiplies the driving signal shown in Expression (1) by a weight that takes into account the disturbance of the composite wavefront due to the speaker array reproduction and the non-flatness of the frequency characteristics, It achieves good composite wavefront and frequency characteristics.
図５は、本発明の一実施形態に係るスピーカアレイ駆動装置１の機能ブロックを示す図である。スピーカアレイ駆動装置１は、駆動信号計算部１０と、信号分配器２０と、合成波面乱れ度計算部３０と、周波数特性計算部４０と、周波数特性非平坦度計算部５０と、重み係数計算部６０と、重み係数乗算部７０と、増幅器８０と、スピーカアレイ９０と、を備える。 FIG. 5 is a diagram showing functional blocks of the speaker array driving apparatus 1 according to one embodiment of the present invention. The speaker array driving apparatus 1 includes a drive signal calculation unit 10, a signal distributor 20, a combined wavefront disturbance degree calculation unit 30, a frequency characteristic calculation unit 40, a frequency characteristic non-flatness calculation unit 50, and a weight coefficient calculation unit. 60, a weighting factor multiplier 70, an amplifier 80, and a speaker array 90.
駆動信号計算部１０は、２２．２チャネル音響の各チャネルの信号から、スピーカアレイ９０用の駆動信号を計算する。駆動信号計算部１０は、仮想音像位置とスピーカアレイ９０中のスピーカの位置に基づきスピーカアレイ９０の駆動信号を計算する。具体的には、駆動信号計算部１０は、式（１）によりスピーカアレイ９０の駆動信号を計算し、計算した駆動信号を信号分配器２０に出力する。なお、スピーカアレイ駆動装置１において、スピーカアレイ９０の各スピーカ位置は既知であるものとする。 The drive signal calculation unit 10 calculates a drive signal for the speaker array 90 from the signal of each channel of 22.2 channel sound. The drive signal calculation unit 10 calculates a drive signal for the speaker array 90 based on the virtual sound image position and the position of the speaker in the speaker array 90. Specifically, the drive signal calculation unit 10 calculates a drive signal for the speaker array 90 according to Equation (1), and outputs the calculated drive signal to the signal distributor 20. In the speaker array driving apparatus 1, each speaker position of the speaker array 90 is known.
信号分配器２０は、駆動信号計算部１０の出力を、合成波面乱れ度計算部３０、周波数特性計算部４０、及び重み係数計算部７０に出力する。 The signal distributor 20 outputs the output of the drive signal calculation unit 10 to the combined wavefront disturbance degree calculation unit 30, the frequency characteristic calculation unit 40, and the weight coefficient calculation unit 70.
重み係数乗算部７０は、駆動信号計算部１０からの駆動信号に対して重み係数を乗算した重み付け駆動信号を増幅器８０に出力する。以下、スピーカアレイ再生による合成波面の乱れ度及び周波数特性の非平坦度を考慮した重み係数の計算方法について詳述する。 The weighting factor multiplier 70 outputs a weighted driving signal obtained by multiplying the driving signal from the driving signal calculator 10 by the weighting factor to the amplifier 80. Hereinafter, a method of calculating a weighting factor in consideration of the degree of disturbance of the synthesized wavefront and the non-flatness of the frequency characteristics due to speaker array reproduction will be described in detail.
合成波面乱れ度計算部３０は、重み付け駆動信号をスピーカアレイ９０により再生した際の受音点を含む受音エリアでの音波の合成波面の乱れ度（合成波面乱れ度）を計算する。ここで、合成波面乱れ度は、適宜定めた受音点を含む受音エリアにおいて、仮想音像位置に実音像を置いた場合の音圧と、重み付け駆動信号をスピーカアレイ９０により再生した際の音圧との差の二乗を積分したものである。受音エリアをＲＡとし、各スピーカが点音源で近似できるとすると、仮想音像位置に実音源を置いた場合の受音点ｒＡ∈ＲＡにおける音圧は、式（２）で表される。ここで、Gはスピーカから単位距離離れた点での音圧と単位駆動信号との比例定数であり、ｒｓ（ｒｓ＝（ｘｓ，ｙｓ，ｚｓ））は形成すべき仮想音像位置である。 The synthesized wavefront turbulence degree calculation unit 30 calculates the turbulence degree of the synthesized wavefront (synthetic wavefront turbulence degree) of the sound wave in the sound receiving area including the sound receiving point when the weighted drive signal is reproduced by the speaker array 90. Here, the synthesized wavefront disturbance degree is the sound pressure when the real sound image is placed at the virtual sound image position in the sound receiving area including the sound receiving point determined as appropriate, and the sound when the weighted drive signal is reproduced by the speaker array 90. It is the integration of the square of the difference from the pressure. Assuming that the sound receiving area is R A and each speaker can be approximated by a point sound source, the sound pressure at the sound receiving point r A ∈R A when the real sound source is placed at the virtual sound image position is expressed by equation (2). The Here, G is a proportional constant between the sound pressure at a point away from the speaker and the unit drive signal, and r s (r s = (x s , y s , z s )) is a virtual sound image to be formed. Position.
また、スピーカアレイ９０による音圧は、式（３）で表される。ここで、Lはスピーカアレイ９０におけるスピーカの個数、ｒｊ（ｒｊ＝（ｘｊ、ｙｊ、ｚｊ））はｊ番目（ｊ＝１〜L）のスピーカの位置、ｗｊを重み係数計算部６０により計算されたｊ番目のスピーカの駆動信号に対する重み係数、ｗはｗｊを要素とするベクトルである。 Further, the sound pressure by the speaker array 90 is expressed by Expression (3). Here, L is the number of speakers in the speaker array 90, r j (r j = (x j , y j , z j )) is the position of the j-th (j = 1 to L) speaker, and w j is a weighting factor. The weight coefficient for the drive signal of the j-th speaker calculated by the calculation unit 60, w is a vector having w j as an element.
合成波面乱れ度計算部３０は、式（２）に示す実音像を置いた場合の音圧と、式（３）に示すスピーカアレイ９０による音圧とから、合成波面乱れ度を式（４）により計算する。ここで、Ｔは予め定めた時間区間である。 The synthetic wavefront disturbance degree calculation unit 30 calculates the synthetic wavefront disturbance degree from the sound pressure when the real sound image shown in Expression (2) is placed and the sound pressure by the speaker array 90 shown in Expression (3). Calculate according to Here, T is a predetermined time interval.
合成波面乱れ度計算部３０は、計算した合成波面乱れ度Ｅｐ（ｗ）を、重み係数計算部６０に出力する。 The combined wavefront disturbance degree calculation unit 30 outputs the calculated combined wavefront disturbance degree E p (w) to the weighting coefficient calculation unit 60.
周波数特性計算部４０は、重み付け駆動信号によりスピーカアレイ９０を駆動することにより受音点で得られる周波数特性を計算する。式（３）に示すスピーカアレイ９０による音圧に単位インパルス関数δ（ｔ）を代入して、フーリエ変換を行うと、受音点ｒＡにおける周波数応答は、式（５）により表される。ここで、Ｆはフーリエ変換であり、ｆは周波数を表す。 The frequency characteristic calculator 40 calculates the frequency characteristic obtained at the sound receiving point by driving the speaker array 90 with the weighted drive signal. When the unit impulse function δ (t) is substituted into the sound pressure by the speaker array 90 shown in Equation (3) and Fourier transform is performed, the frequency response at the sound receiving point r A is expressed by Equation (5). Here, F is a Fourier transform, and f represents a frequency.
周波数特性計算部４０は、ｆを０ＨｚからＦｓ／２Ｈｚまで変化させることにより、式（６）で示す周波数特性を得る。なおＦｓは信号周波数の上限を表す。 The frequency characteristic calculator 40 obtains the frequency characteristic represented by Expression (6) by changing f from 0 Hz to Fs / 2 Hz. Fs represents the upper limit of the signal frequency.
周波数特性計算部４０は、計算した周波数特性を周波数特性非平坦度計算部５０に出力する。 The frequency characteristic calculation unit 40 outputs the calculated frequency characteristic to the frequency characteristic non-flatness calculation unit 50.
周波数特性非平坦度計算部５０は、周波数特性の概形に着目し、式（６）の周波数特性を式（８）に示す多項式により近似する。 The frequency characteristic non-flatness calculation unit 50 pays attention to the outline of the frequency characteristic, and approximates the frequency characteristic of Expression (6) by a polynomial shown in Expression (8).
周波数特性非平坦度計算部５０は、計算した周波数特性非平坦度Ｅｆ（ｗ）を重み係数計算部６０に出力する。 The frequency characteristic non-flatness calculation unit 50 outputs the calculated frequency characteristic non-flatness E f (w) to the weighting coefficient calculation unit 60.
重み係数計算部６０は、合成波面乱れ度計算部３０からの合成波面乱れ度Ｅｐ（ｗ）と、周波数特性非平坦度計算部５０からの周波数特性非平坦度Ｅｆ（ｗ）とにより式（１０）に示す誤差関数を定義し、当該誤差関数を最小化する重み係数ｗを計算する。ここで、γは予め定めた係数である。 The weighting factor calculation unit 60 uses the combined wavefront disturbance degree E p (w) from the combined wavefront disturbance degree calculation unit 30 and the frequency characteristic nonflatness E f (w) from the frequency characteristic nonflatness calculation unit 50 to calculate an equation. The error function shown in (10) is defined, and a weighting coefficient w that minimizes the error function is calculated. Here, γ is a predetermined coefficient.
重み係数ｗの求め方については、種々の方法があるが、例えば、重み係数計算部６０は、simulated annealing法（例えば非特許文献２参照）を用いた繰り返し処理により、誤差関数を最小化する重み係数を算出することができる。simulated annealing法は、重み係数の初期値に対して誤差関数を計算した後重み係数に摂動を与え、その結果誤差関数が小さくなった場合には、摂動を与えた重み係数を新たな重み係数として採用する。また、重み係数に摂動を与えた結果誤差関数が大きくなった場合でも、温度と呼ばれるパラメータによって定まる確率にしたがって、摂動を与えられた重み係数を新たな重み係数として採用するものである。 There are various methods for obtaining the weight coefficient w. For example, the weight coefficient calculation unit 60 performs weighting that minimizes the error function by iterative processing using a simulated annealing method (see, for example, Non-Patent Document 2). A coefficient can be calculated. In the simulated annealing method, after calculating the error function with respect to the initial value of the weighting factor, a perturbation is given to the weighting factor. As a result, when the error function becomes small, the weighting factor with the perturbation is used as a new weighting factor. adopt. Further, even when the error function increases as a result of perturbing the weighting factor, the weighting factor given the perturbation is employed as a new weighting factor according to the probability determined by a parameter called temperature.
重み係数計算部６０は、計算した重み係数を重み係数乗算部７０に出力する。 The weighting factor calculation unit 60 outputs the calculated weighting factor to the weighting factor multiplication unit 70.
重み係数乗算部７０は、上述の通り、駆動信号計算部１０からの駆動信号に対して、重み係数計算部６０からの重み係数を乗算し、乗算後の駆動信号を増幅器８０に出力する。 As described above, the weighting factor multiplier 70 multiplies the driving signal from the driving signal calculator 10 by the weighting factor from the weighting factor calculator 60, and outputs the multiplied driving signal to the amplifier 80.
増幅器８０は、重み係数乗算部７０からの駆動信号を増幅し、スピーカアレイ９０の各スピーカに出力する。 The amplifier 80 amplifies the drive signal from the weight coefficient multiplication unit 70 and outputs it to each speaker of the speaker array 90.
スピーカアレイ９０の各スピーカは、増幅器８０より入力される駆動信号をそれぞれ音に変換して放射する。 Each speaker of the speaker array 90 converts the drive signal input from the amplifier 80 into sound and radiates it.
このように、本実施形態によれば、重み係数計算部６０は、周波数特性の非平坦度と合成波面の乱れ度とを最小化するように重み係数を計算し、重み係数乗算部７０は、駆動信号に対して重み係数を乗算して重み付け駆動信号を生成する。これにより、映像ディスプレイの周囲に設置可能なスピーカアレイ９０において、実際のスピーカが配置されていない仮想音像からの音波の合成波面や音の周波数特性を改善することができる。また、例えば、スーパーハイビジョン用の２２．２チャネル音響信号の前方１１チャネルを、映像ディスプレイの周りに配したスピーカアレイによって高音質で再生することが可能となり、将来の３次元音響の家庭導入が促進される。 As described above, according to the present embodiment, the weighting factor calculation unit 60 calculates the weighting factor so as to minimize the non-flatness of the frequency characteristic and the degree of disturbance of the combined wavefront, and the weighting factor multiplication unit 70 A weighted drive signal is generated by multiplying the drive signal by a weighting factor. Thereby, in the speaker array 90 that can be installed around the video display, it is possible to improve the synthetic wavefront of sound waves and the frequency characteristics of sound from a virtual sound image in which no actual speaker is arranged. In addition, for example, the front 11 channels of 22.2 channel sound signals for Super Hi-Vision can be played back with high sound quality by a speaker array placed around the video display, and the future introduction of 3D sound into the home is promoted. Is done.
また、周波数特性非平坦度計算部５０は、周波数特性を多項式近似し、当該多項式の係数の二乗和に基づいて前記周波数特性の非平坦度を計算する。これにより、平坦周波数特性に対する周波数特性の概形の非平坦度を定量的に計算することが可能となる。 Further, the frequency characteristic non-flatness calculation unit 50 approximates the frequency characteristic by a polynomial, and calculates the non-flatness of the frequency characteristic based on the square sum of the coefficients of the polynomial. Thereby, it is possible to quantitatively calculate the non-flatness of the rough shape of the frequency characteristic with respect to the flat frequency characteristic.
また、合成波面乱れ度計算部３０は、仮想音像位置に実音像を置いた場合の音圧と、重み付け駆動信号をスピーカアレイ９０により再生した際の音圧との差分を、受音エリアにおいて空間的に積分することにより、合成波面の乱れ度を計算する。これにより、これにより、実音像による波面に対するスピーカアレイ９０による波面の乱れ度を定量的に計算することが可能となる。 In addition, the synthesized wavefront disturbance degree calculation unit 30 calculates a difference between the sound pressure when the real sound image is placed at the virtual sound image position and the sound pressure when the weighted drive signal is reproduced by the speaker array 90 in the sound receiving area. The degree of turbulence of the composite wavefront is calculated by integrating it. Thereby, it becomes possible to quantitatively calculate the degree of disturbance of the wavefront by the speaker array 90 with respect to the wavefront of the actual sound image.
本発明を諸図面や実施例に基づき説明してきたが、当業者であれば本開示に基づき種々の変形や修正を行うことが容易であることに注意されたい。従って、これらの変形や修正は本発明の範囲に含まれることに留意されたい。例えば、各構成部材、各手段などに含まれる機能などは論理的に矛盾しないように再配置可能であり、複数の構成部や手段などを１つに組み合わせたり、或いは分割したりすることが可能である。 Although the present invention has been described based on the drawings and examples, it should be noted that those skilled in the art can easily make various modifications and corrections based on the present disclosure. Therefore, it should be noted that these variations and modifications are included in the scope of the present invention. For example, the functions included in each component, each means, etc. can be rearranged so that there is no logical contradiction, and a plurality of components, means, etc. can be combined into one or divided. It is.
例えば、スピーカアレイ駆動装置１は、２２．２チャネル音響のうち、ＦＣチャネル、ＦＬｃチャネル、ＦＲｃチャネルなど、実スピーカが存在しない表示部ＤＩＳ内のチャネルの入力信号について、重み係数乗算部７０により重み付け駆動信号を求め、ＴｐＦＬチャネルのように、実スピーカが存在するチャネルの入力信号については、式（１）に示す駆動信号をそのままスピーカアレイ９０の駆動信号とすることができる。 For example, the speaker array driving apparatus 1 weights the input signal of the channel in the display unit DIS where there is no real speaker, such as the FC channel, the FLc channel, and the FRc channel, out of the 22.2 channel sound, by the weight coefficient multiplication unit 70. A drive signal is obtained, and the drive signal shown in Expression (1) can be used as the drive signal of the speaker array 90 as it is for the input signal of the channel where the actual speaker is present, such as the TpFL channel.
また、上記実施形態においては、表示部ＤＩＳを方形状の映像ディスプレイとして説明を行ったが、本発明は、方形状のディスプレイに限らず中央部分にスピーカを有しない任意のスピーカアレイに適応可能である。さらに、映像ディスプレイの周りにスピーカを配したスピーカアレイに限らず、任意のスピーカアレイにも適用可能な技術であることは言うまでもない。 In the above embodiment, the display unit DIS has been described as a rectangular video display. However, the present invention is not limited to a rectangular display, and can be applied to any speaker array that does not have a speaker in the center. is there. Furthermore, it goes without saying that the present invention is not limited to a speaker array in which speakers are arranged around a video display, but can be applied to any speaker array.
本発明によれば、映像ディスプレイの周囲に配置可能なスピーカアレイにおいて、実際のスピーカが配置されていない仮想音像からの音波の合成波面や音の周波数特性を改善することができるという有用性がある。 Advantageous Effects of Invention According to the present invention, in a speaker array that can be arranged around a video display, there is a usefulness that it is possible to improve the synthesized wavefront of sound waves and the frequency characteristics of sound from a virtual sound image in which no actual speaker is arranged. .
１ スピーカアレイ駆動装置
１０ 駆動信号計算部
２０ 信号分配器
３０ 合成波面乱れ度計算部
４０ 周波数特性計算部
５０ 周波数特性非平坦度計算部
６０ 重み係数計算部
７０ 重み係数乗算部
８０ 増幅器
９０ スピーカアレイ
ＤＩＳ 表示部
DESCRIPTION OF SYMBOLS 1 Speaker array drive device 10 Drive signal calculation part 20 Signal distributor 30 Synthetic wavefront disorder degree calculation part 40 Frequency characteristic calculation part 50 Frequency characteristic non-flatness calculation part 60 Weight coefficient calculation part 70 Weight coefficient multiplication part 80 Amplifier 90 Speaker array DIS Display section
Claims (4)
仮想音像位置と前記スピーカアレイ中のスピーカの位置に基づき前記スピーカアレイの駆動信号を計算する駆動信号計算部と、
前記駆動信号に対して重み係数を乗算して重み付け駆動信号を生成する重み係数乗算部と、
前記重み付け駆動信号により前記スピーカアレイを駆動することにより受音点で得られる周波数特性を計算する周波数特性計算部と、
前記周波数特性の非平坦度を計算する周波数特性非平坦度計算部と、
前記重み付け駆動信号を前記スピーカアレイにより再生した際の前記受音点を含む受音エリアでの音波の合成波面の乱れ度を計算する合成波面乱れ度計算部と、
前記周波数特性の非平坦度と前記合成波面の乱れ度とを最小化するように前記重み係数を計算する重み係数計算部と、を備えるスピーカアレイ駆動装置。 A loudspeaker array having a plurality of loudspeakers, a virtual sound image position, and a drive signal calculation unit for calculating a drive signal of the loudspeaker array based on the positions of the loudspeakers in the loudspeaker array;
A weighting factor multiplier for multiplying the driving signal by a weighting factor to generate a weighting driving signal;
A frequency characteristic calculator that calculates a frequency characteristic obtained at a sound receiving point by driving the speaker array with the weighted drive signal;
A frequency characteristic non-flatness calculator that calculates non-flatness of the frequency characteristic;
A synthetic wavefront turbulence degree calculation unit for calculating a turbulence degree of a synthetic wavefront of a sound wave in a sound receiving area including the sound receiving point when the weighted driving signal is reproduced by the speaker array;
A speaker array driving device comprising: a weighting factor calculation unit that calculates the weighting factor so as to minimize the non-flatness of the frequency characteristic and the degree of disturbance of the combined wavefront.
前記スピーカアレイ駆動装置による処理手順が、
仮想音像位置と前記スピーカアレイ中のスピーカの位置に基づき前記スピーカアレイの駆動信号を計算するステップと、
前記駆動信号に対して重み係数を乗算して重み付け駆動信号を生成するステップと、
前記重み付け駆動信号により前記スピーカアレイを駆動することにより受音点で得られる周波数特性を計算するステップと、
前記周波数特性の非平坦度を計算するステップと、
前記重み付け駆動信号を前記スピーカアレイにより再生した際の前記受音点を含む受音エリアでの音波の合成波面の乱れ度を計算するステップと、
前記周波数特性の非平坦度と前記合成波面の乱れ度とを最小化するように前記重み係数を計算するステップと、を備えるスピーカアレイ駆動方法。 A speaker array driving method in a speaker array driving apparatus including a speaker array having a plurality of speakers,
The processing procedure by the speaker array driving device is as follows:
Calculating a driving signal of the speaker array based on a virtual sound image position and a position of the speaker in the speaker array;
Multiplying the drive signal by a weighting factor to generate a weighted drive signal;
Calculating a frequency characteristic obtained at a sound receiving point by driving the speaker array with the weighted drive signal;
Calculating the non-flatness of the frequency characteristic;
Calculating the degree of disturbance of the composite wavefront of the sound wave in the sound receiving area including the sound receiving point when the weighted drive signal is reproduced by the speaker array;
And a step of calculating the weighting factor so as to minimize the non-flatness of the frequency characteristic and the degree of disturbance of the combined wavefront.
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