WO2020087678A1 - 一种多通路三维空间环绕声的虚拟重放方法 - Google Patents

一种多通路三维空间环绕声的虚拟重放方法 Download PDF

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WO2020087678A1
WO2020087678A1 PCT/CN2018/120990 CN2018120990W WO2020087678A1 WO 2020087678 A1 WO2020087678 A1 WO 2020087678A1 CN 2018120990 W CN2018120990 W CN 2018120990W WO 2020087678 A1 WO2020087678 A1 WO 2020087678A1
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signals
sum
signal
channel
virtual
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PCT/CN2018/120990
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English (en)
French (fr)
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谢波荪
张承云
刘路路
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华南理工大学
广州大学
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Priority to US17/290,778 priority Critical patent/US11962995B2/en
Publication of WO2020087678A1 publication Critical patent/WO2020087678A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S7/00—Indicating arrangements; Control arrangements, e.g. balance control
    • H04S7/30—Control circuits for electronic adaptation of the sound field
    • H04S7/302—Electronic adaptation of stereophonic sound system to listener position or orientation
    • H04S7/303—Tracking of listener position or orientation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S7/00—Indicating arrangements; Control arrangements, e.g. balance control
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R3/00—Circuits for transducers, loudspeakers or microphones
    • H04R3/12—Circuits for transducers, loudspeakers or microphones for distributing signals to two or more loudspeakers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R5/00—Stereophonic arrangements
    • H04R5/02—Spatial or constructional arrangements of loudspeakers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S7/00—Indicating arrangements; Control arrangements, e.g. balance control
    • H04S7/30—Control circuits for electronic adaptation of the sound field
    • H04S7/302—Electronic adaptation of stereophonic sound system to listener position or orientation
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S2400/00—Details of stereophonic systems covered by H04S but not provided for in its groups
    • H04S2400/11—Positioning of individual sound objects, e.g. moving airplane, within a sound field
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04S—STEREOPHONIC SYSTEMS 
    • H04S2420/00—Techniques used stereophonic systems covered by H04S but not provided for in its groups
    • H04S2420/01—Enhancing the perception of the sound image or of the spatial distribution using head related transfer functions [HRTF's] or equivalents thereof, e.g. interaural time difference [ITD] or interaural level difference [ILD]

Definitions

  • the invention relates to the technical field of electroacoustics, and specifically refers to a virtual playback method of multi-channel three-dimensional space surround sound.
  • multi-channel surround sound technology has developed from traditional horizontal surround sound to three-dimensional surround sound, and is applied to the fields of movies, home audio and video playback, etc.
  • Traditional horizontal surround sound is arranged with horizontal speakers.
  • the 5.1 channel surround sound recommended by the International Telecommunication Union is a full-range speaker arrangement with left L, middle C and right R in front of the horizontal plane, left surround LS and right surround RS, plus optional sub-low frequency speakers .
  • the replay effect of three-dimensional surround sound is obviously improved compared with horizontal surround sound, but it is more complicated and requires more replay speakers, usually in the form of a layered arrangement.
  • the simplest 9.1-channel spatial surround sound includes 9 full-band speakers, plus a selectable subwoofer.
  • a two-layer loudspeaker arrangement including a horizontal layer and an upper (high) layer is adopted, in which the five full-band speaker arrangements on the horizontal layer are consistent with the 5.1 channel surround sound recommended by the International Telecommunication Union; the four full-band speakers on the upper layer are arranged on the horizontal layer Above the left, right, left surround and right surround speakers.
  • the method of virtual playback can be adopted to reduce the playback speakers.
  • the basic principle is that after multi-channel surround sound signals are subjected to signal processing and mixing through a head-related transfer function (HRTF), they become fewer channel signals, which are then replayed with a smaller number of real speakers, resulting in similar
  • HRTF head-related transfer function
  • the two patented technologies can be used for horizontal surround sound playback of TV sets, and use a pair of left and right speakers arranged on both sides of the TV set, or a pair of left and right channels arranged on the TV (or below) with integrated left and right channels Bar speaker system (called “Sound Blaster” or “Sound” Bar) is implemented.
  • the present invention is based on the prior art, and further provides a virtual playback method of multi-channel three-dimensional spatial surround sound.
  • the method uses HRTF (Head Related Transfer Function) signal processing to convert the multi-channel spatial surround sound signal into a four-channel signal and replay it with four speakers arranged in front left, front right, front left upper, and front right upper.
  • HRTF Head Related Transfer Function
  • a pair of bar speaker systems i.e. dual-sound system
  • a pair of bar speaker systems that are vertically arranged on the left and right sides of the TV (each system includes , The next two speakers), or a pair of speakers arranged on the left and right sides of the TV and a bar speaker system arranged above the TV to achieve playback.
  • a virtual playback method of multi-channel three-dimensional spatial surround sound according to the present invention includes the following steps and processing conditions:
  • the first step place the four speakers in the horizontal front left and front right, and the front left and top right positions on the 30 ° ⁇ 15 ° elevation plane.
  • Step two the original spatial surround sound input level layer via the M (an even number) non-prior signal E after the direction of the non-passage 1, E 2 ... ..E M, and possible forward direction path signal E M + 1 And backward direction path signal E M + 2 .
  • Step 3 Input the signals of the original spatial surround sound upper channel m '(even) non-front and non-rear direction channels E' 1 , E ' 2 ... E' M ' , and possible forward direction channel signals E ' M' + 1 and the backward direction signal E ' M' + 2 .
  • Step 4 Among the M channel signals of the horizontal layer, add and subtract (sum difference) each left half-space channel signal and the symmetric right half-space channel signal to obtain M / 2 sum signals of the horizontal layer ( E 1 + E 2 ), (E 3 + E 4 ).... (E M-1 + E M ), and M / 2 difference signals (E 1 -E 2 ), (E 3 -E 4 ) ... (E M-1 -E M ).
  • Step 5 In the upper M 'channel signals, add and subtract (sum difference) each left half-space channel signal and the symmetric right half-space channel signal to obtain the upper layer M' / 2 sum signals ( E ' 1 + E' 2 ), (E ' 3 + E' 4 ) ... (E ' M'-1 + E' M '+ 1 ), and the upper M' / 2 difference signals (E ' 1 -E ' 2 ), (E' 3 -E ' 4 ) ... (E' M'-1 -E ' M' ).
  • Step 6 M / 2 sum signals of the horizontal layer are respectively filtered and summed by M / 2 virtual playback signal processing functions ⁇ 1,2 , ⁇ 3,4 ... ⁇ M-1, M , and then added
  • the possible path signals E M + 1 and E M + 2 in the front and back directions of the upper possible horizontal layer, and the total signal E SUM ⁇ 1,2 (E 1 + E 2 ) + ⁇ 3,4 (E 3 + E 4 ).... + ⁇ M-1, M (E M + E M + 1 ) + E M + 1 + E M + 2 .
  • Step 8 Filter the upper M '/ 2 sum signals with M' / 2 virtual replay signal processing functions ⁇ ' 1,2 , ⁇ ' 3,4 ... ⁇ ' M'-1,M'
  • E ' SUM ⁇ ' 1,2 (E ' 1 + E ' 2 ) + ⁇ ' 3,4 (E ' 3 + E' 4 ).
  • Step 10 Add and subtract the sum signal E SUM and the total difference signal E DIF of the horizontal layer, and attenuate to obtain the playback signals of the real front left and right front speakers respectively, and feed the signals to the corresponding real speakers for playback ;
  • Step 11 Perform sum and difference operations on the sum signal E ' SUM and the total difference signal E' DIF of the upper layer, and attenuate to obtain the replay signals of the real front left and top right speakers respectively, and feed the signals to the corresponding real speakers Replay.
  • M / 2 virtual playback signal processing functions ⁇ 1,2 , ⁇ 3,4 ... ⁇ M-1, M are used for filtering, and in the seventh step, M / 2 virtual playback is used
  • the signal processing functions ⁇ 1,2 , ⁇ 3,4 ... ⁇ M-1, M are filtered, that is, the virtual playback signal processing function obtained according to the following formula is filtered:
  • HRTF head-related transfer functions
  • H L ( ⁇ ' m' , f), H R ( ⁇ ' m' , f) are head-related transfer functions (HRTF) from the upper virtual speaker in the direction of ⁇ ' m' to the left and right ears;
  • HRTF head-related transfer functions
  • the principle of the present invention is: according to the basic theory of virtual auditory playback, real left and right front loudspeakers arranged on a certain elevation angle plane can generate multiple virtual speakers on the front half elevation plane.
  • Four real speakers are used for virtual playback, of which two speakers are respectively arranged at the front left and front right of the horizontal plane, and the other two speakers are respectively arranged at the top left and front right of the high elevation plane.
  • the virtual auditory playback signal processing can generate a horizontal speaker of the multi-channel spatial surround sound and the front half-plane virtual speaker of the upper layer, thereby producing a three-dimensional spatial surround sound effect, including the effect in the vertical direction.
  • a pair of bar speaker systems arranged above and below the TV or a pair of bar speaker systems arranged vertically on the left and right sides of the TV, or a pair of bar speaker systems arranged on the left and right of the TV, respectively
  • the right speaker and a bar speaker system arranged above the TV set are equivalent to the combination of a pair of left front and right front real speakers on a horizontal plane and a pair of left front upper and right front real speakers on a high elevation plane, so that this can be achieved invention.
  • the present invention has the following advantages and beneficial effects:
  • the present invention performs virtual processing on the independent original signals of multi-channel spatial surround sound, and uses four speakers arranged at the front left and front right positions of the horizontal plane, and the front left and top right positions of the high elevation angle surface to reproduce.
  • the original multi-channel spatial surround sound speakers are simple to arrange, and can produce three-dimensional spatial surround sound effects, including vertical effects.
  • the speaker arrangement of the present invention is suitable for TV and other video playback applications.
  • the present invention is compatible with the two-speaker virtual playback of traditional 5.1-channel surround sound.
  • the present invention can be designed as dedicated hardware or general software for sound playback in digital televisions, home theaters, etc., and can also be used as hardware or software for sound playback in multimedia computers.
  • FIG. 1 is a schematic diagram of implementing the present invention by using a pair of bar speaker systems arranged above and below a television, respectively.
  • FIG. 2 is a schematic diagram of implementing the present invention by using a pair of vertically arranged bar speaker systems on the left and right sides of the television, respectively.
  • FIG. 3 is a schematic diagram of a pair of speakers respectively arranged on the left and right sides of the television and a bar-shaped speaker system arranged above the television to implement the present invention.
  • Fig. 4 is a schematic diagram of a horizontal front left speaker, a front right speaker, and a high elevation angle left front upper and front upper speaker arrangement.
  • FIG. 5 is a block diagram of the signal processing of the present invention.
  • Fig. 6a is a schematic diagram of the horizontal layer arrangement of a 9.1-channel spatial surround sound speaker.
  • Figure 6b is a schematic diagram of the upper layer arrangement of a 9.1-channel spatial surround sound speaker.
  • a virtual playback method of multi-channel three-dimensional space surround sound the speaker is first arranged, the coordinates are selected as elevation angle -90 ° ⁇ 90 °, azimuth angle -180 ° ⁇ 180 °.
  • the playback effect is the left front L1, right front R1, left front shown in Figure 4
  • the front left and right speakers are arranged in a horizontal plane (of course, it may be slightly lower), and their elevation angles are:
  • the opening angle between the real front left and front right speakers is smaller than the standard stereo speaker arrangement of 60 °, usually between 20 ° and 30 °. Therefore, the azimuths of the real front left and right speakers are:
  • the real speakers on the top left and front right are arranged higher than the horizontal plane, and the elevation angle is
  • the azimuths of the upper left and upper right speakers are:
  • multi-channel spatial surround sound there are many different formats for multi-channel spatial surround sound, generally including the two-layer (horizontal layer and upper layer) channel signal and speaker arrangement as shown in Figure 5.
  • the channel signals are E 1 , E 2 ... E M + 2
  • m 1, 2 (M + 2), of which M
  • the channel signals are E' 1 , E ' 2 ... E' M '+ 2
  • m' 1, 2 (M ' +2)
  • the azimuths of M 'non-front or non-rear speakers are respectively ⁇ ' m '
  • m' 1, 2 ... M '
  • the virtual replay signal processing function is given by:
  • H L ( ⁇ m , f) and H R ( ⁇ m , f) are head-related transfer functions (HRTF) from the virtual speaker to the left and right ears in the direction of the horizontal plane ⁇ m , and f is the frequency.
  • HRTF head-related transfer functions
  • the virtual replay signal processing function is given by:
  • H L ( ⁇ ' m' , f) and H R ( ⁇ ' m' , f) are head-related transfer functions (HRTF) from the upper virtual speaker in the direction of ⁇ ' m' to the left and right ears, respectively.
  • HRTF head-related transfer functions
  • the multi-channel spatial surround sound speaker arrangement is symmetrical to the left and right. Using symmetry simplifies signal processing.
  • the signals of the M non-positive front and non-positive back channels in the water layer are sorted by odd numbers representing the left half-space channels and even numbers representing the symmetric right half-space channels. :
  • the signals of the upper M 'non-positive front and non-positive back channels are sorted by odd numbers representing the left half-space channels, and even numbers representing the symmetric right half-space channels, then the virtual signal function processing of (8) has the following symmetry :
  • the virtual signal processing of equations (10) and (13) includes (M + M ') filters, which is half of the original (5) and (7) equation 2 (M + M') filters, thus improving Signal processing efficiency.
  • 5 is a block diagram of the input signal processing of the horizontal layer and the upper layer of the present invention obtained according to equations (10) and (13).
  • the inverse Fourier transform can be used to convert the frequency domain signal processing of equations (10) and (13) into corresponding time domain signal processing.
  • Embodiment 1 Application of Blu-ray Disc Player and TV
  • the Blu-ray disc player decodes the multi-channel spatial surround sound (digital) signal obtained from the digital transmission medium and performs virtual processing according to the method in FIG. 5, four-channel signals E L1 , E R1 , E L2 and E R2 are obtained , and then Feed a pair of bar speaker systems arranged above and below the TV (display), or a pair of bar speaker systems arranged vertically on the left and right sides of the TV, or a pair of bar speaker systems respectively arranged on the left of the TV , The speakers on the right side and a bar speaker system arranged above the TV set, reproduce the effect of spatial surround sound.
  • the virtual signal processing can be used as a part of the hardware circuit in the Blu-ray disc player, a part of the hardware circuit of the TV set, or a hardware circuit inside the active speaker system.
  • Embodiment 2 home theater application
  • the multi-channel spatial surround sound (digital) signal decoded by the Blu-ray disc player or output from the digital transmission media is fed to the amplifier of the home theater.
  • the virtual signal processing in FIG. 5 is a part of the functional circuit in the amplifier.
  • the four-channel signals E L1 , E R1 , E L2 and E R2 are obtained and fed to four external full-band speakers for playback respectively.
  • Embodiment 3 Application of multimedia computer
  • the multi-channel spatial surround sound (digital) signal read by the computer's Blu-ray drive, or decoded through digital transmission media, and then the computer software is used to perform the virtual signal processing of Figure 5 (you can also use a dedicated sound card on the computer (Hardware circuit implementation), get four channels of signals E L1 , E R1 , E L2 and E R2 and feed them to four full-band speakers that are externally connected or built into the computer for playback.
  • the present invention specifically introduces the 9.1 channel spatial surround sound virtual playback in TV applications as an implementation example, and implements the present invention with a hardware circuit made by a general-purpose signal processing chip (DSP).
  • DSP general-purpose signal processing chip
  • the present invention is not limited to the virtual playback of 9.1-channel spatial surround sound, but also includes the virtual playback of other multi-channel spatial surround sound, such as 11.1 channel and 13.1 channel spatial surround sound playback.
  • the invention is not limited to the application of TV, but also includes other applications, such as the application of Blu-ray disc player, the application of home theater, the application of multimedia computer, etc.
  • the present invention is not limited to being implemented with a general-purpose DSP, but can also be implemented in other ways, such as a dedicated integrated circuit chip, or a software implemented on a multimedia computer.
  • the 9.1 channel surround sound is the simplest three-dimensional space surround sound system.
  • the 9.1 channel spatial surround sound includes a two-layer speaker arrangement and 9 independent full-band channel signals.
  • the layout is shown in Figures 6a and 6b.
  • the odd numbers represent the left half-space channels, and the even numbers represent the symmetric right half-space channels.
  • the number of each signal is:
  • the elevation angle of the corresponding speakers on the horizontal layer is 0 °, and the azimuth angles are:
  • the odd numbers represent the left half-space channels, and the even numbers represent the symmetric right half-space channels.
  • the number of each signal is:
  • the corresponding elevation speakers have an elevation angle of 30 ° and an azimuth angle of:
  • the processing method is the same as the signal in the horizontal center channel.
  • a hardware circuit composed of a general-purpose signal processing chip (ADAU1701) is used to realize virtual signal processing, and is used as part of the hardware circuit in the (active) real bar speaker system.
  • the signal processing used is the HRTF data of the KEMAR artificial head measured by experiment, the sampling frequency is 44.1kHz.
  • a virtual impulse response (FIR) filter is used for virtual signal processing, with a filter length of 128 points.
  • the first step place the two bar speaker systems above and below the TV, with the elevation angle of each speaker being 0 ° and 30 °, and the azimuth angle being ⁇ 15 °;
  • Step 2 Input the original 9.1-channel spatial surround sound horizontal layer 5 channel signals, including left E L , right E R , left surround E LS , right surround E RS , the front center channel E C ;
  • the third step input the original 9.1 channel spatial surround sound upper 4 channel signals, including upper left E ' LH , upper right E' RH , upper left surround E ' LSH and upper right surround E' RSH ;
  • Step 4 Add and subtract (sum difference) each left half-space channel signal of the horizontal layer and the symmetric right half-space channel signal to obtain two sum signals (E L + E R ) and (E LS + E RS ), and 2 difference signals (E L -E R ), (E LS -E RS ) of the horizontal layer;
  • Step 5 Add and subtract (sum difference) each left half-space channel signal of the upper layer and the symmetric right half-space channel signal to obtain two upper-level sum signals (E ' LH + E' RH ), (E ' LSH + E' RSH ), and the 2 difference signals of the upper layer (E ' LH -E' RH ), (E ' LSH -E' RSH );
  • a key to evaluating the virtual playback of multi-channel spatial surround sound is the effect of virtual speakers, that is, the perception direction of each virtual speaker.
  • the five virtual speakers in the horizontal layer and the signal processing are completely the same as the existing 5.1-channel surround sound two-player virtual playback, and the effect should be the same. Therefore, the subjective evaluation experiment focuses on verifying the positioning effect of the upper four virtual speakers.
  • the experiment was conducted in a listening room with a reverberation time of 0.15s.
  • the original experimental signals included language signals (Mandarin male voice), music signals (orchestral music: John Strausch, blue Danube fragment). After signal processing, the signals corresponding to the positions of the four virtual speakers in the upper layer of the 9.1-channel spatial surround sound are generated respectively, and real speakers are used.
  • the listener judges the position of the perceived virtual speaker and repeats the judgment 3 times under each playback condition.
  • statistical analysis is performed on 24 judgments under each playback condition.
  • the statistical parameters to measure the positioning effect include: the front-to-back confusion rate of the virtual source, the top-to-bottom confusion rate, the average unsigned azimuth error and standard deviation, and the average unsigned elevation error and standard deviation. The results are shown in Table 1.

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Abstract

本发明所述的一种多通路三维空间环绕声的虚拟重放方法,它将多通路空间环绕声的信号经过和差运算和虚拟重放信号处理函数处理后，反馈给布置在水平的左前、右前，30°±10°高仰角面的左前上、右前上位置的四个真实扬声器重放，产生三维空间环绕声的听觉效果。本发明使多通路空间环绕声所需的重放扬声器数量与布置得到简化，适用于电视等不宜布置空间环绕声多个扬声器的场合。

Description

一种多通路三维空间环绕声的虚拟重放方法 技术领域
本发明涉及电声技术领域，具体是指一种多通路三维空间环绕声的虚拟重放方法。
背景技术
目前多通路环绕声技术已经由传统的水平面环绕声发展到三维空间环绕声，并应用到电影、家用声视频重放等领域。传统的水平面环绕声是采用水平面扬声器布置的。例如国际电信联盟推荐的家用5.1通路环绕声是采用水平面前方左L、中C、右R，侧后方左环绕LS、右环绕RS共五个全频带扬声器布置，加上可选择的次低频扬声器。三维空间环绕声的重放效果较水平面环绕声有明显的提高，但更为复杂，需要更多的重放扬声器，通常是采用分层布置的形式。例如在家用重放中，最简单的9.1通路空间环绕声包括9个全频带扬声器，加上1个可选择的次低频扬声器。采用包括水平层和上(高)层的两层扬声器布置，其中水平层5个全频带扬声器布置和国际电信联盟推荐的5.1通路环绕声的布置一致；上层的4个全频带扬声器布置在水平层左、右、左环绕和右环绕扬声器的上方。
而对于电视等应用，以及由于室内条件的限制，有时并不一定适合布置空间环绕声的多个扬声器。因而可以采用虚拟重放的方法，减少重放扬声器。其基本原理是，将多通路环绕声信号经过头相关传输函数(HRTF)进行信号处理和混合后，变成较少通路信号，再利用较少数量的真实扬声器进行重放，从而得到类似于多通路环绕声的效果,达到简化多通路环绕声的目的。
对水平面的5.1通路环绕声重放，国外已发展了采用前方两真实扬声器虚拟重放的专利技术和产品(如SRS、Qsurround,Dolby等)，但普遍存在一定的缺陷，特别是听音区域较窄、重放音色改变等。在国家发明专利授权(ZL02134416.7，ZL 2006 1 0037495.0)中，克服了过去技术听音区域窄、重放音色改变等问题，并对头相关传输函数滤波器进行了简化。该两个专利技术可用于电视机的水平面环绕声重放，并用一对布置在电视机两侧的左、右扬声器，或者一个布置布置在电视上(或下)方且集成左、右通路的条形扬声器系统(称为“声霸”或“Sound Bar”)实现。
国外也发展了采用前方两真实扬声器虚拟重放空间环绕声的技术。虽然这类技术结构较为简单，但由于两真实扬声器重放本身的物理原理限制，这类技术只能产生前半水平面的声音空间效果，不能产生稳定垂直方向的空间环绕声效果。
发明内容
本发明是在现有技术的基础上，进一步提供一种多通路三维空间环绕声的虚拟重放方 法。该方法采用HRTF(Head Related Transfer Function，头相关传输函数)信号处理，将多通路空间环绕声信号转换为四通路信号，并用布置在左前、右前、左前上、右前上四个扬声器重放。实际中可用一对分别布置在电视机上方和下方的条形扬声器系统(即双声霸系统)，或者一对分别在电视机左、右两侧的竖布置扬声器条形扬声器系统(每系统包含上、下两扬声器)、或者一对分别布置在电视机左、右两侧的扬声器和一个布置在电视机上方的条形扬声器系统实现重放。
本发明所述的一种多通路三维空间环绕声的虚拟重放方法,包括如下步骤和处理条件：
第一步：将四个扬声器分别布置在水平的左前、右前，30°±15°仰角面的左前上、右前上位置。
第二步：输入原始的空间环绕声水平层通路的M(偶数)个非前、非后方向通路的信号E 1,E 2…..E M,以及可能的前方向通路信号E M+1和后方向通路信号E M+2。将M个通路的信号按奇数编号代表左半空间通路、偶数编号代表对称的右半空间通路排序，其中m＝1,2…M；
第三步：输入原始的空间环绕声上层通路的m'(偶数)个非前、非后方向通路的信号E' 1,E' 2…..E' M',以及可能的前方向通路信号E' M'+1和后方向通路信号E' M'+2。将M’个通路的信号按奇数编号代表左半空间通路、偶数编号代表对称的右半空间通路排序，其中m'＝1,2…M'；
第四步：在水平层的M个通路信号中，将每个左半空间通路信号与对称的右半空间通路信号进行加减(和差)运算，得到水平层的M/2个和信号(E 1+E 2),(E 3+E 4)….(E M-1+E M)，以及水平层的M/2个差信号(E 1-E 2),(E 3-E 4)….(E M-1-E M)。
第五步：在上层的M'个通路信号中，将每个左半空间通路信号与对称的右半空间通路信号进行加减(和差)运算，得到上层的M'/2个和信号(E' 1+E' 2),(E' 3+E' 4)….(E' M'-1+E' M'+1)，以及上层的M'/2个差信号(E' 1-E' 2),(E' 3-E' 4)….(E' M'-1-E' M')。
第六步：将水平层的M/2个和信号分别用M/2个虚拟重放信号处理函数Σ 1,2，Σ 3,4…Σ M-1,M进行滤波后求和，再加上可能的水平层前、后方向通路信号E M+1,E M+2，得到水平层的总和信号E SUM＝Σ 1,2(E 1+E 2)+Σ 3,4(E 3+E 4)….+Σ M-1,M(E M+E M+1)+E M+1+E M+2。
第七步：将水平层的M/2个差信号分别用M/2个虚拟重放信号处理函数Δ 1,2，Δ 3,4…Δ M-1,M进行滤波后求和，得到水平层的总差信号E DIF＝Δ 1,2(E 1-E 2)+Δ 3,4(E 3-E 4)….+Δ M-1,M(E M-1-E M))。
第八步：将上层的M'/2个和信号分别用M'/2个虚拟重放信号处理函数Σ' 1,2，Σ' 3,4…Σ' M'-1,M'进行滤波后求和，再加上可能的上层前、后方向通路信号E' M'+1,E' M'+2，得到上层的总和信号E' SUM＝Σ' 1,2(E' 1+E' 2)+Σ' 3,4(E' 3+E' 4)….+Σ' M'-1,M'(E' M'+E' M'+1)+E' M'+1+E' M'+2。
第九步：将上层的M'/2个差信号分别用M'/2个虚拟重放信号处理函数Δ' 1,2，Δ' 3,4…Δ' M-1,M进行滤波处理后求和，得到上层的总差信号E' DIF＝Δ' 1,2(E' 1-E' 2)+Δ' 3,4(E' 3- E' 4)….+Δ' M'-1,M'(E' M'-E' M'+1)。
第十步：对水平层的总和信号E SUM、总差信号E DIF进行加和差运算，并衰减分别得到水平面左前、右前真实扬声器的重放信号，并将信号馈给相应的真实扬声器重放；
第十一步：对上层的总和信号E' SUM、总差信号E' DIF进行和差运算，并衰减分别得到左前上、右前上真实扬声器的重放信号，并将信号馈给相应的真实扬声器重放。
进一步的，第十步中：对水平层的总和信号E SUM、总差信号E DIF进行加和差运算，并衰减-3dB即乘以0.7后，分别得到水平面左前、右前真实扬声器的重放信号E L1＝0.7(E SUM+E DIF)、E R1＝0.7(E SUM-E DIF)，并将信号馈给相应的真实扬声器重放。
进一步的，第十一步中：对上层的总和信号E' SUM、总差信号E' DIF进行和差运算，并衰减-3dB即乘以0.7后，分别得到左前上、右前上真实扬声器的重放信号E L2＝0.7(E' SUM+E' DIF)、E R2＝0.7(E' SUM–E' DIF)，并将信号馈给相应的真实扬声器重放。
进一步的，第六步中用M/2个虚拟重放信号处理函数Σ 1,2，Σ 3,4…Σ M-1,M进行滤波，以及第七步中用M/2个虚拟重放信号处理函数Δ 1,2，Δ 3,4…Δ M-1,M进行滤波，就是根据以下公式得到的虚拟重放信号处理函数进行滤波：
Σ m,m+1＝0.707[A 1(θ m,ω)+A 1(θ m+1,ω)]
Δ m,m+1＝0.707[A 1(θ m,ω)-A 1(θ m+1,ω)]
Figure PCTCN2018120990-appb-000001
H L(θ m,f)、H R(θ m,f)分别为水平面θ m方向的虚拟扬声器到左和右耳的头相关传输函数(HRTF)，f为频率；α 1＝α 1(f)和β 1＝β 1(f)分别为布置在水平面的左前或者右前真实扬声器到同侧和异侧耳的频域传输函数。
进一步的，第八步中用M'/2个虚拟重放信号处理函数Σ' 1,2，Σ' 3,4…Σ' M'-1,M'进行滤波，以及第九步中用M'/2个虚拟重放信号处理函数Δ' 1,2，Δ' 3,4…Δ' M'-1,M'进行滤波，就是根据以下公式得到的虚拟重放信号处理函数进行滤波：
Σ' m',m'+1＝0.707[A 2(θ' m',f)+A 2(θ' m'+1,f)]
Δ' m',m'+1＝0.707[A 2(θ' m',f)-A 1(θ' m'+1,f)]
Figure PCTCN2018120990-appb-000002
H L(θ' m',f)、H R(θ' m',f)分别为上层θ' m'方向的虚拟扬声器到左和右耳的头相关传输函数(HRTF)；α 2＝α 2(f)和β 2＝β 2(f)分别为左前上或者右前上真实扬声器到同侧和异侧耳的频域传输函数。
本发明的原理是：根据虚拟听觉重放的基本理论，布置在某一仰角面的左前、右前真实扬声器可以在该前半仰角面产生多个虚拟扬声器。采用四个真实扬声器进行虚拟重放，其中两个扬声器分别布置在水平面左前、右前的位置，另外两个扬声器分别布置在高仰角面左前上、右前上的位置。虚拟听觉重放信号处理可以产生多通路空间环绕声的水平层和上层的前半平面虚拟扬声器，从而产生三维空间环声的效果，包括垂直方向的效果。实际应用中，一对分别布置在电视机上方和下方的条形扬声器系统，或者一对分别在电视机左、右两侧的竖布置条形扬声器系统，或者一对分别布置在电视机左、右的扬声器和一个布置在电视机上方的条形扬声器系统，都等价于水平面的一对左前、右前真实扬声器与高仰角面的一对左前上、右前上真实扬声器的组合，因而可实现本发明。
本发明与现有技术相比，具有如下优点和有益效果：
1.本发明对多通路空间环绕声的独立原始信号进行虚拟处理后，用布置在水平面左前、右前的位置，以及高仰角面左前上、右前上位置的四个扬声器重放，其硬件结构较原先的多通路空间环绕声扬声器布置简单，同时可产生三维空间环声的效果，包括垂直方向的效果。
2.本发明的扬声器布置适合电视和其他视频重放的应用。
3.本发明可兼容实现传统的5.1通路环绕声的两扬声器虚拟重放。
4.本发明可设计成专用硬件或通用软件而用在数字电视、家庭影院等方面的声音重放，也可作为硬件或软件用在多媒体计算机的声音重放。
附图说明
图1是采用一对分别布置在电视机上方和下方的条形扬声器系统实现本发明的示意图。
图2是采用一对分别在电视机左、右两侧的竖布置条形扬声器系统实现本发明的示意图。
图3是一对分别布置在电视机左、右两侧的扬声器和一个布置在电视机上方的条形扬声器系统实现本发明的示意图。
图4是水平面左前、右前扬声器，以及高仰角左前上、有前上扬声器布置的示意图。
图5是本发明信号处理的方框图。
图6a是9.1通路空间环绕声扬声器水平层布置的示意图。
图6b是9.1通路空间环绕声扬声器上层布置的示意图。
具体实施方式
下面结合附图和实施例，对本发明做进一步的详细说明，但本发明的实施和保护范围不限于此。
本实例的一种多通路三维空间环绕声的虚拟重放方法，先布置扬声器，坐标选取为仰角 -90°≤φ≤90°，方位角-180°<θ≤180°。其中φ＝-90°,0°和90°分别表示正下方、水平面和正上方；在水平面，θ＝0°,90°和180°分别表示正前、正左和正后方。
如图1、图2和图3所示，为一对分别布置在电视机四周的扬声器系统，无论哪种方式实现本发明，重放效果都为图4所示的左前L1、右前R1，左前上L2、右前上R2四个扬声器的放置效果。左前、右前扬声器布置在水平面(当然也可能是略低的位置)，其仰角为：
φ L1＝φ R1＝0°       (1)
对电视机的实际应用，左前、右前真实扬声器之间的张角较标准的立体声扬声器布置的60°小，通常在20°到30°之间。因而左前、右前真实扬声器的方位角为：
θ L1＝10°～15° θ R1＝-10°～-15°      (2)
左前上、右前上真实扬声器布置在比水平面高的位置，其仰角为
φ L2＝φ R2＝30°±15°        (3)
而左前上、右前上扬声器的方位角为：
θ L2＝10°～15° θ R2＝-10°～-15°       (4)
多通路空间环绕声有多种不同的制式，一般包含如图5所示的两层(水平层和上层)通路的信号和扬声器布置。假设水平层有M+2个扬声器,其通路信号为E 1,E 2…..E M+2,仰角为φ m＝0°，m＝1,2…(M+2),其中M个非正前或非正后方的扬声器的方位角分别为θ m，m＝1,2….M,而正前和正后方扬声器的(如果存在)的方位角分别为θ M+1＝0°和θ M+2＝180°。上层有M’+2个扬声器,其通路信号为E' 1,E' 2…..E' M'+2，仰角为φ' m'＝φ H，m'＝1,2…(M'+2),其中M'个非前或非后方的扬声器的方位角分别为θ' m’，m'＝1,2….M'，而前和后方扬声器(如果存在)的方位角分别为θ' M'+1＝0°和θ' M'+2＝180°。
将多通路空间环绕声水平层的非正前和非正后方的M个通路信号用虚拟重放信号处理函数处理并进行和差运算，得到水平层的总和信号E SUM＝Σ 1,2(E 1+E 2)+Σ 3,4(E 3+E 4)….+Σ M-1,M(E M+E M+1)+E M+1+E M+2和水平层的总差信号E DIF＝Δ 1,2(E 1-E 2)+Δ 3,4(E 3-E 4)….+Δ M-1,M(E M-1-E M)；并与水平层正前和正后方信号(如果存在)衰减-3dB(乘以系数0.7)后混合，再馈给左前、右前真实扬声器。根据虚拟重放与真实重放双耳声压相等、再加上重放信号功率谱不变的条件，左前、右前的一对真实扬声器重放的信号为：
Figure PCTCN2018120990-appb-000003
其中,虚拟重放信号处理函数由下式给出:
Figure PCTCN2018120990-appb-000004
H L(θ m,f)、H R(θ m,f)分别为水平面θ m方向的虚拟扬声器到左和右耳的头相关传输函数(HRTF)，f为频率。假设水平面左、右真实扬声器相对于倾听者是左、右对称的，α 1＝α 1(f)和β 1＝β 1(f)分别为布置在水平面的左前(右前)真实扬声器到同侧和异侧耳的频域传输函数(同侧和异侧HRTF)。
将多通路空间环绕声上层的非前和非后方M’个通路信号用虚拟重放信号处理函数处理并进行加减运算，得到上层的总和信号E' SUM＝Σ' 1,2(E' 1+E' 2)+Σ' 3,4(E' 3+E' 4)….+Σ' M'-1,M'(E' M'+E' M'+1)+E' M'+1+E' M'+2和上层的总差信号E' DIF＝Δ' 1,2(E' 1-E' 2)+Δ' 3,4(E' 3-E' 4)….+Δ' M'1,M’(E' M'-E' M'+1)；并与上层前和后方信号(如果存在)衰减-3dB(乘以系数0.7)后混合，再馈给左前上、右前上真实扬声器。根据虚拟重放与真实重放双耳声压相等、再加上重放信号功率谱不变的条件，左前上、右前上的一对真实扬声器重放的信号为：
Figure PCTCN2018120990-appb-000005
其中,虚拟重放信号处理函数由下式给出:
Figure PCTCN2018120990-appb-000006
H L(θ' m',f)、H R(θ' m',f)分别为上层θ' m'方向的虚拟扬声器到左和右耳的头相关传输函数(HRTF)。假设左前上、右前上真实扬声器相对于倾听者是左、右对称的，α 2＝α 2(f)和β 2＝β 2(f)分别为左前上(右前上)真实扬声器到同侧和异侧耳的频域传输函数(同侧和异侧HRTF)。
一般情况下，多通路空间环绕声的扬声器布置是左、右对称的。利用对称性可简化信号 处理。将水层M个非正前、非正后通路的信号按奇数编号代表左半空间通路、偶数编号代表对称的右半空间通路排序，则(6)式的虚拟信号处理函数有以下的对称关系：
Figure PCTCN2018120990-appb-000007
则(5)式的信号处理与下面(10)式是等价的：
Figure PCTCN2018120990-appb-000008
上式是对m为奇数求和，而:
Figure PCTCN2018120990-appb-000009
将上层M'个非正前、非正后通路的信号按奇数编号代表左半空间通路、偶数编号代表对称的右半空间通路排序，则(8)式的虚拟信号函数处理有以下的对称关系：
Figure PCTCN2018120990-appb-000010
则(7)式的信号处理与下面(13)式是等价的：
Figure PCTCN2018120990-appb-000011
上式是对m'为奇数求和，而:
Figure PCTCN2018120990-appb-000012
(10)式和(13)式的虚拟信号处理共包括(M+M')个滤波器，是原先(5)和(7)式2(M+M’)个滤波器的一半，因而提高了信号处理的效率。图5是根据(10)和(13)式得到的本发明水平层和上层输入信号处理的框图。在实际实施中，可利用逆傅立叶变换，将(10)式和(13)式的 频域信号处理转换为相应的时域信号处理。
实施例一 蓝光光盘播放机与电视的应用
将蓝光光盘播放机解码输出或从数字传输媒体得到的多通路空间环绕声(数字)信号按图5的方法进行虚拟处理后，得到四通路信号E L1、E R1、E L2和E R2，然后馈给一对分别布置在电视机(显示器)上方和下方的条形扬声器系统，或者一对分别在电视机左、右两侧的竖布置条形扬声器系统，或者一对分别布置在电视机左、右两侧的扬声器和一个布置在电视机上方的条形扬声器系统，重放出空间环绕声的效果。其中，虚拟信号处理可作为蓝光光盘播放机内的一部分硬件电路，也可作为电视机的一部分硬件电路，或者有源扬声器系统内部的硬件电路。
实施例二 家庭影院的应用
将蓝光光盘播放机解码输出或从数字传输媒体得到的多通路空间环绕声(数字)信号馈给家庭影院的放大器，图5的虚拟信号处理是作为放大器内的一部分功能电路。得到四通路信号E L1、E R1、E L2和E R2后分别馈给外接的四个全频带扬声器进行重放。
实施例三 多媒体计算机的应用
由计算机的蓝光光驱读取，或通过数字传输媒体并经解码得到的多通路空间环绕声(数字)信号，然后用计算机软件实行图5的虚拟信号处理(也可以在计算机的声卡上用专用的硬件电路实现)，得到四通路信号E L1、E R1、E L2和E R2后分别馈给外接或计算机自带的四个全频带扬声器进行重放。
本发明具体介绍9.1通路空间环绕声虚拟重放在电视应用作为其中的实施例子,并以通用的信号处理芯片(DSP)所做成的硬件电路实现本发明。但本发明并不限定于9.1通路空间环绕声的虚拟重放，也包括其它多通路空间环绕声的虚拟重放,如11.1通路、13.1通路空间环绕声重放。本发明并不限定于电视的应用,也包括其它的应用,如蓝光光盘播放机的应用、家庭影院的应用、多媒体计算机的应用等。本发明也不限定于用通用DSP实现，也可以用其他方式实现，如设计成专用的集成电路芯片实现，还可以设计成软件在多媒体计算机上实现。
9.1通路环绕声是最简单的三维空间环绕声系统。9.1通路空间环绕声共包括有两层扬声器布置和9个独立的全频带通路信号。其布置位置如图6a和图6b所示，水平层L、C、R、LS、RS共5个扬声器，上层有LH、RH、LSH、RSH共4个扬声器，另外再加上可选择的低频效果通路(扬声器)。水平层包括M＝4个左、右对称的非前、非后方通路信号，即左E L、右E R、左环绕E LS、右环绕E RS，加上前方的中心通路E C。按奇数编号代表左半空间通路、偶数编号代表对称的右半空间通路排序，各信号的编号为：
E 1＝E L E 2＝E R E 3＝E LS E 4＝E RS E 5＝E C        (15)
对应的水平层各扬声器的仰角为0°，方位角为分别：
θ 1＝θ L＝30° θ 2＝θ R＝-30° θ 3＝θ LS＝110° θ 4＝θ RS＝-110° θ 5＝θ C＝0°
                                                  (16)
9.1通路空间环绕声上层共包括M'＝4个左、右对称的非前、非后方通路信号，即左上E' LH、右上E' RH、左上环绕E' LSH和右上环绕E' RSH，没有前方或后方通路信号。按奇数编号代表左半空间通路、偶数编号代表对称的右半空间通路排序，各信号的编号为：
E' 1＝E' LH E' 2＝E' RH E' 3＝E' LSH E' 4＝E' RSH           (17)
对应的上层各扬声器的仰角为30°，方位角为分别：
θ' 1＝θ' LH＝30° θ' 2＝θ' RH＝-30° θ' 3＝θ' LSH＝110° θ' 4＝θ' RSH＝-110°  (18)
利用9.1通路环绕声的扬声器布置参数，即可按上述(10)和(13)式的方法实现虚拟信号处理。由于前半空间的真实扬声器不能产生后半空间的虚拟声源(虚拟扬声器)，因而信号处理参数中将水平层和上层虚拟环绕扬声器前移两侧而取其方位角为
θ 3＝θ LS＝90° θ 4＝θ RS＝-90° θ' 3＝θ' LS＝90° θ' 4＝θ' RS＝-90°   (19)
对低频效果通路信号，其处理方式和水平面中心通路的信号相同。
将蓝光光盘播放机解码输出或从数字传输媒体得到的9.1通路空间环绕声(数字)信号进行虚拟处理后，得到四通路信号E L1、E R1、E L2和E R2，然后用一对分别布置在电视机上方和下方的真实条形扬声器系统进行重放。采用通用信号处理芯片(ADAU1701)组成的硬件电路实现虚拟信号处理，并作为(有源)真实条形扬声器系统内的硬件电路的一部分。信号处理所用的是实验测量得到的KEMAR人工头的HRTF数据，采样频率44.1kHz。采用有限脉冲响应(FIR)滤波器实现虚拟信号处理，滤波器长度128点。
具体实施的步骤：
第一步：将两个条形扬声器系统分别布置在电视机上方和下方，各扬声器的仰角分别为0°和30°，方位角为±15°；
第二步：输入原始的9.1通路空间环绕声水平层的5个通路信号，包括左E L、右E R、左环绕E LS、右环绕E RS，前方的中心通路E C；
第三步：输入原始的9.1通路空间环绕声上层的4个通路信号，包括左上E' LH、右上E' RH、左上环绕E' LSH和右上环绕E' RSH；
第四步：将水平层的每个左半空间通路信号与对称的右半空间通路信号进行加减(和差)运算，得到水平层的2个和信号(E L+E R)、(E LS+E RS)，以及水平层的2个差信号(E L-E R)、(E LS-E RS)；
第五步：将上层的每个左半空间通路信号与对称的右半空间通路信号进行加减(和差)运算，得到上层的2个和信号(E' LH+E' RH)、(E' LSH+E' RSH)，以及上层的2个差信号(E' LH-E' RH)、(E' LSH-E' RSH)；
第六步：将水平层的2个和信号分别用2个虚拟重放信号处理函数Σ 1,2、Σ 3,4进行滤波 后求和，加上中心通路信号，得到水平层的总和信号E SUM＝Σ 1,2(E L+E R)+Σ 3,4(E LS+E RS)+E C；
第七步：将水平层的2个差信号分别用2个虚拟重放信号处理函数Δ 1,2，Δ 3,4进行滤波后求和，得到水平层的总差信号E DIF＝Δ 1,2(E L-E R)+Δ 3,4(E LS-E RS)；
第八步：将上层的2个和信号分别用2个虚拟重放信号处理函数Σ' 1,2、Σ' 3,4滤波后求和，得到上层的总和信号E' SUM＝Σ' 1,2(E' LH+E' RH)+Σ' 3,4(E' LSH+E' RSH)；
第九步：将上层的2个差信号分别用2个虚拟重放信号处理函数Δ' 1,2、Δ' 3,4进行滤波后求和，得到上层的总差信号E' DIF＝Δ' 1,2(E' LH-E' RH)+Δ' 3,4(E' LSH-E' RSH)；
第十步：对水平层的总和信号E SUM、总差信号E DIF进行加减(和差)运算，并衰减-3dB(乘以0.7)后，得到水平面左前、右前真实扬声器的重放信号E L1＝0.7(E SUM+E DIF)、E R1＝0.7(E SUM-E DIF)，将它们馈给相应的真实扬声器重放。
第十一步：对上层的总和信号E' SUM、总差信号E' DIF进行加减(和差)运算，并衰减-3dB(乘以0.7)后，得到左前上、右前上真实扬声器的重放信号E L2＝0.7(E' SUM+E' DIF)、E R2＝0.7(E' SUM–E' DIF)，将它们馈给相应的真实扬声器重放。
如上所述，即可较好地实现本发明。
由于9.1通路空间环绕声水平层的5个通路和扬声器布置是和传统的5.1水平面环绕声是一致的，因而本发明的信号处理与现有的5.1通路环绕声的两扬声器虚拟重放完全兼容(国家发明专利授权,ZL02134416.7)。
主观评价实验验证了本发明的实际效果。评价多通路空间环绕声虚拟重放的一个关键是虚拟扬声器的效果，也就是评价各虚拟扬声器的感知方向。在本发明的9.1通路空间环绕声虚拟重放的实施例中，水平层的5个虚拟扬声器、信号处理与现有的5.1通路环绕声的两扬声器虚拟重放完全相同，效果也理应相同。因而主观评价实验重点验证上层的4个虚拟扬声器的定位效果。
实验是在一间混响时间0.15s的听音室进行，四个真实扬声器的仰角和方位角为φ L1＝φ R1＝0°，φ L2＝φ R2＝30°；θ L1＝θ L2＝15°，θ R1＝θ R2＝-10°，与倾听者头中心距离1.5m。原始的实验信号包括语言信号(普通话男声),音乐信号(管弦乐:约翰.斯特劳施,蓝色的多瑙河片段)。经过信号处理，分别产生对应9.1通路空间环绕声上层4个虚拟扬声器位置的信号，并用真实扬声器。
实验中，倾听者判断感知虚拟扬声器的位置，在每种重放条件下重复判断3次。共8名受试者参加实验，因而每种重放条件下有24个判断。最后对每种重放条件下24个判断进行统计分析。衡量定位效果的统计参量包括:虚拟源的前后混乱率、上下混乱率、平均无符号方位角误差及标准差、平均无符号仰角误差及标准差。结果如表1所示。
表1定位实验结果统计
Figure PCTCN2018120990-appb-000013
由表1看出，重放没出现感知虚拟源前后和上下混乱的情况。平均无符号仰角误差都不大，因而可以产生垂直方向的定位感知。侧向目标方位角θ＝±90°平均无符号方位角误差较大，实际感知虚拟源的方位角在60°附近，这是虚拟处理固有的缺陷。因此虚拟源定位实验验证了本发明。

Claims (5)

  1. 一种多通路三维空间环绕声的虚拟重放方法，其特征是，包括如下步骤：
    第一步：将四个扬声器分别布置在水平的左前、右前，30°±15°仰角面的左前上、右前上位置；
    第二步：输入原始的空间环绕声水平层通路的m个非前、非后方向通路的信号E 1,E 2.....E M,以及可能的前方向通路信号E M+1和后方向通路信号E M+2，M为偶数；将M个通路的信号按奇数编号代表左半空间通路、偶数编号代表对称的右半空间通路排序，其中m＝1,2…M；
    第三步：输入原始的空间环绕声上层通路的m'个非前、非后方向通路的信号E' 1,E' 2.....E' M',以及可能的前方向通路信号E' M'+1和后方向通路信号E' M'+2，m'为偶数；将M'个通路的信号按奇数编号代表左半空间通路、偶数编号代表对称的右半空间通路排序，其中m'＝1,2…M'；
    第四步：在水平层的M个通路信号中，将每个左半空间通路信号与对称的右半空间通路信号进行和差运算，得到水平层的M/2个和信号(E 1+E 2),(E 3+E 4)....(E M-1+E M)，以及水平层的M/2个差信号(E 1-E 2),(E 3-E 4)....(E M-1-E M)；
    第五步：在上层的M'个通路信号中，将每个左半空间通路信号与对称的右半空间通路信号进行和差运算，得到上层的M'/2个和信号E' 1+E' 2),(E' 3+E' 4)....(E' M'-1+E' M'+1)，以及上层的M'/2个差信号(E' 1-E' 2),(E' 3-E' 4)....(E' M'-1-E' M')；
    第六步：将水平层的M/2个和信号分别用M/2个虚拟重放信号处理函数Σ 1,2，Σ 3,4…Σ M-1,M进行滤波后求和，再加上可能的水平层前、后方向通路信号E M+1,E M+2，得到水平层的总和信号E SUM＝Σ 1,2(E 1+E 2)+Σ 3,4(E 3+E 4)....+Σ M-1,M(E M+E M+1)+E M+1+E M+2；
    第七步：将水平层的M/2个差信号分别用M/2个虚拟重放信号处理函数Δ 1,2，Δ 3,4…Δ M-1,M进行滤波后求和，得到水平层的总差信号E DIF＝Δ 1,2(E 1-E 2)+Δ 3,4(E 3-E 4)....+Δ M-1,M(E M-1-E M)；
    第八步：将上层的M'/2个和信号分别用M'/2个虚拟重放信号处理函数Σ' 1,2，Σ' 3,4…Σ' M’-1,M'进行滤波后求和，再加上可能的上层前、后方向通路信号E M'+1,E M'+2，得到上层的总和信号E' SUM＝Σ' 1,2(E' 1+E' 2)+Σ' 3,4(E' 3+E' 4)....+Σ' M'-1,M'(E' M'+E' M'+1)+E' M'+1+E' M'+2；
    第九步：将上层的M'/2个差信号分别用M'/2个虚拟重放信号处理函数Δ' 1,2，Δ' 3,4…Δ' M'1,M'进行滤波处理后求和，得到上层的总差信号E' DIF＝Δ' 1,2(E' 1-E' 2)+Δ' 3,4(E' 3-E' 4)....+Δ' M'-1,M'(E' M'-E' M' +1)；
    第十步：对水平层的总和信号E SUM、总差信号E DIF进行加和差运算，并衰减分别得到水平面左前、右前真实扬声器的重放信号，并将信号馈给相应的真实扬声器重放；
    第十一步：对上层的总和信号E' SUM、总差信号E' DIF进行和差运算，并衰减分别得到左前上、右前上真实扬声器的重放信号，并将信号馈给相应的真实扬声器重放。
  2. 根据权利要求1所述的一种多通路三维空间环绕声的虚拟重放方法，其特征是，第十步中：对水平层的总和信号E SUM、总差信号E DIF进行加和差运算，并衰减-3dB即乘以0.7后，分别得到水平面左前、右前真实扬声器的重放信号E L1＝0.7(E SUM+E DIF)、E R1＝0.7(E SUM-E DIF)，并将信号馈给相应的真实扬声器重放。
  3. 根据权利要求1所述的一种多通路三维空间环绕声的虚拟重放方法，其特征是，第十一步中：对上层的总和信号E' SUM、总差信号E' DIF进行和差运算，并衰减-3dB即乘以0.7后，分别得到左前上、右前上真实扬声器的重放信号E L2＝0.7(E' SUM+E' DIF)、E R2＝0.7(E' SUM–E' DIF)，并将信号馈给相应的真实扬声器重放。
  4. 根据权利要求1所述的一种多通路三维空间环绕声的虚拟重放方法，其特征是，第六步中用M/2个虚拟重放信号处理函数Σ 1,2，Σ 3,4…Σ M-1,M进行滤波，以及第七步中用M/2个虚拟重放信号处理函数Δ 1,2，Δ 3,4…Δ M-1,M进行滤波，就是根据以下公式得到的虚拟重放信号处理函数进行滤波：
    Σ m,m+1＝0.707[A 1(θ m,f)+A 1(θ m+1,f)]
    Δ m,m+1＝0.707[A 1(θ m,f)-A 1(θ m+1,f)]
    Figure PCTCN2018120990-appb-100001
    H L(θ m,f)、H R(θ m,f)分别为水平面方位角θ m方向的虚拟扬声器到左和右耳的头相关传输函数(HRTF)，f为频率；α 1＝α 1(f)和β 1＝β 1(f)分别为布置在水平面的左前或者右前真实扬声器到同侧和异侧耳的频域传输函数。
  5. 根据权利要求1所述的一种多通路三维空间环绕声的虚拟重放方法，其特征是，第八步中用M'/2个虚拟重放信号处理函数Σ' 1,2，Σ' 3,4…Σ' M' 1,M'进行滤波，以及第九步中用M'/2个虚拟重放信号处理函数Δ' 1,2，Δ' 3,4…Δ' M'-1,M'进行滤波，就是根据以下公式得到的虚拟重放信号处理函数进行滤波：
    Σ' m',m'+1＝0.707[A 2(θ' m',f)+A 2(θ' m'+1,f)]
    Δ' m',m'+1＝0.707[A 2(θ' m',f)-A 1(θ' m'+1,f)]
    Figure PCTCN2018120990-appb-100002
    H L(θ' m',f)、H R(θ' m',f)分别为上层方位角θ' m'方向的虚拟扬声器到左和右耳的头相关传输函数(HRTF)；α 2＝α 2(f)和β 2＝β 2(f)分别为左前上或者右前上真实扬声器到同侧和异侧耳的频域传输函数。
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