Acoustic signal processing device

Abstract

The problem is to provide an "acoustic signal processing device" capable of using a sound signal with a smaller number of channels to achieve an acoustic effect that gives a listener a spatial recognition of surround sound that exceeds that of the past. The solution is to have: a spatial separation processing unit (1) that generates a spatial component sound signal for each of a plurality of spatial components corresponding to a plurality of virtual sound sources set at different spatial positions, respectively, from input sound signals of a plurality of channels; and a unification processing unit (2) that adds the spatial component sound signals of the plurality of channels generated by the spatial separation processing unit (1) for each of the plurality of spatial components to the input sound signals of the plurality of channels, and is capable of achieving an acoustic effect that gives a listener a spatial recognition of surround sound that exceeds that of the past by performing a sound emphasis process on the input sound signals of the plurality of channels for each spatial component.

Description

Technical Field

[0001] This disclosure relates to audio signal processing devices. Background Technology

[0002] In recent years, technologies known as immersive sound or immersive audio have garnered attention. Immersive sound is an audio technology that creates a sense of realism and immersion, as if the sound were heard from all directions, such as stereo sound or 3D surround sound, making the listener feel as if they were actually there. Unlike traditional surround sound, which expands the sound field in a planar manner, immersive sound expands the sound field in three dimensions.

[0003] In immersive sound, the use of multi-channel surround sound, such as 7.1.4 channels, is trending; however, most existing sound sources are two-channel or have a relatively small number of channels. Therefore, there is a need to achieve sound effects exceeding the required number of channels using existing sound sources with fewer channels. Furthermore, several techniques are known regarding sound signal processing for imparting sound effects (see, for example, Patent Documents 1-3).

[0004] In the audio processing apparatus described in Patent Document 1, a converted spatial audio signal is determined based on an input spatial audio signal. The input spatial audio signal has an input audio characteristic and an input direction of arrival, and the converted spatial audio signal has an omnidirectional audio component and at least one directional audio component. The audio processing apparatus estimates a wave characteristic including a wave field quantity and a wave direction of arrival quantity based on the input audio characteristic and the input direction of arrival, and obtains the omnidirectional audio component and at least one directional component by processing the wave field quantity and the wave direction of arrival quantity.

[0005] In the audio processing apparatus described in Patent Document 2, an extended downmixing signal is generated based on a multi-channel microphone signal. This apparatus includes: a spatial analyzer that calculates a set of spatial queue parameters, including directional information describing the direction of arrival of the direct tone, direct tone power information, and diffuse tone power information, based on the multi-channel microphone signal; a filter calculator that calculates extended filter parameters depending on the directional information describing the direction of arrival of the direct tone, the direct tone power information, and the diffuse tone power information; and a filter that uses the extended filter parameters to filter the microphone signal or a signal derived from the microphone signal in order to obtain the extended downmixing signal.

[0006] In the audio processing system described in Patent Document 3, the stereo signal is divided into stereo time-frequency signal segments that correspond to frequency domain samples in a given time interval. For each stereo time-frequency signal segment pair, a similarity index representing the degree of similarity between the stereo time-frequency signal segments is determined. Using this similarity index, pairs of central, side stereo segments are generated, thereby decomposing the time-frequency signal segments. Furthermore, a multi-channel signal is generated, comprising a central signal generated based on the central segments and side signals generated based on the side stereo segments.

[0007] The technology described in Patent Document 1 involves a method for resynthesizing sound recorded in a specific format such as directional audio encoding into components for each direction. This method is only valid in the case of a specific format and is difficult to apply to general 2ch stereo sound signals.

[0008] The technology described in Patent Document 2 is a technology for converting multi-channel microphone signals into extended downmixed signals, rather than a technology for multi-channeling audio signals with two or fewer channels.

[0009] The technology described in Patent Document 3 is a technology for generating multi-channel signals based on stereo signals, but it requires calculating parameters such as indices to separate the stereo signals into multiple spatial segments.

[0010] Existing technical documents: Patent documents: Patent Document 1: Japanese Patent Publication No. 2011-530915 Patent Document 2: Japanese Patent Publication No. 2013-520691 Patent Document 3: Japanese Patent Publication No. 2013-527727 Summary of the Invention

[0011] The problem that the invention aims to solve: The purpose of this disclosure is to enable the use of fewer audio channels to achieve a surround sound effect that provides listeners with spatial awareness beyond what has been achieved before.

[0012] Methods used to solve problems: To solve the above problems, this disclosure includes: a spatial separation processing unit that generates spatial component sound signals based on input sound signals from multiple channels for each of multiple spatial components corresponding to multiple virtual sound sources set at different spatial locations; and an integration processing unit that adds the spatial component sound signals generated by the spatial separation processing unit for each of the multiple spatial components to the input sound signals from multiple channels.

[0013] Invention effects: According to the present disclosure as described above, multiple channel input sound signals are added to each of the multiple spatial components, thereby enhancing the sound according to each spatial component and enabling the listener to achieve a sound effect that provides spatial recognition of surround sound beyond previous methods. Attached Figure Description

[0014] Figure 1 This is a diagram illustrating an example of the configuration of the audio signal processing apparatus according to the first embodiment.

[0015] Figure 2 This is a diagram showing an example of the configuration of the space separation processing unit in the first embodiment.

[0016] Figure 3 This is a diagram illustrating an example of the configuration of the filter coefficient calculation circuit in the first embodiment.

[0017] Figure 4 This is a diagram illustrating a configuration example of a modified audio signal processing device.

[0018] Figure 5 This is a diagram illustrating an example of the configuration of the audio signal processing device according to the second embodiment.

[0019] Figure 6 This is a diagram showing an example of the configuration of the space separation processing unit in the second embodiment.

[0020] Figure 7 This is a diagram showing the typical configuration of surround speakers.

[0021] Figure 8A This is a diagram illustrating an example of the configuration of the filter coefficient calculation circuit in the second embodiment.

[0022] Figure 8B This is a diagram illustrating an example of the configuration of the filter coefficient calculation circuit in the second embodiment.

[0023] Explanation of reference numerals in the attached figures: 1, 1B…Spatial separation processing unit; 2, 2A, 2B…Integration processing unit; 3, 3B…Delay circuit; 4, 4A, 4B…Correction processing unit; 5, 5A, 5B…Correction processing unit; 6, 6B…Multichannel processing unit; 10, 10A, 10B…Audio signal processing device; 11… L 11 R …adder, 12 L 12 R …subtractor, 13 L 13 R …delay circuit, 14 L 14 R …FIR filters, 15L 15 R …subtractor, 20, 20B…filter coefficient calculation circuit, 21 L ,twenty one R …adder, 22 L ,twenty two R …subtractor, 23 L ,twenty three R …delay circuit, 24 L ,twenty four R …FIR adaptive filter, 25 L 25 R …subtractor, 26 L 26 R …FIR filters, 27 L 27 R …delay circuit, 31 LS 31 L 31 R 31 RS 32 LS 32 L 32 R 32 RS …adder, 33 LS 33 L 33 R 33 RS 34 LS 34 L 34 R 34 RS …subtractor, 35 LS 35 L 35 R 35 RS …delay circuits, 36 LS 36 L 36 R 36 RS …FIR filters, 37 LS 37 L 37 R 37 RS …subtractor, 41 LS 42 LS …adder, 43 LS 44 LS …subtractor, 45 LS …delay circuits, 46 LS …FIR adaptive filter, 47 LS …subtractor, 48 LS …FIR filters, 49 LS …delay circuit, 101 L 101 R101 LS 101 RS …microphone, 201, 201 LS 201 L 201 R 201 RS …First Signal Processing Department, 202, 202 LS 202 L 202 R 202 RS …Second Signal Processing Unit, 203, 203 LS 203 L 203 R 203 RS …Error signal calculation unit. Detailed Implementation

[0024] (First Implementation) Hereinafter, one embodiment of the present disclosure will be described based on the accompanying drawings. Figure 1 This is a diagram illustrating an example configuration of the audio signal processing apparatus 10 according to the first embodiment. (See diagram below.) Figure 1 As shown, the audio signal processing device 10 of the first embodiment is configured to include a spatial separation processing unit 1, an integration processing unit 2, a delay circuit 3, and correction processing units 4 and 5.

[0025] The spatial separation processing unit 1 generates spatial component sound signals based on the input sound signals from multiple channels for each of the multiple spatial components corresponding to multiple virtual sound sources set at different spatial locations. In the first embodiment, the input sound signals from multiple channels are stereo sound signals consisting of a left channel (Lch) and a right channel (Rch). In the following description, "two channels" refers to Lch and Rch. Furthermore, in the first embodiment, the multiple spatial component sound signals corresponding to the multiple virtual sound sources are spatial component sound signals with N values ​​for Lch (N being any integer greater than 2) and N values ​​for Rch. The multiple virtual sound sources will be described later. The following uses... Figure 2 The spatial components of the sound signal are explained.

[0026] Figure 2 This is a diagram showing an example of the configuration of the space separation processing unit 1. Figure 2 The diagram only illustrates the portion that generates the first spatial component sound signal; the portions that generate the second to Nth spatial component sound signals are simplified. Except for the different filter coefficients used, the components used to generate the first to Nth spatial component sound signals are identical.

[0027] like Figure 2As shown, the spatial separation processing unit 1 generates first to Nth spatial component sound signals for both channels based on the input sound signals from the two channels. Regarding the composition of the first spatial component sound signal generated at Lch, the spatial separation processing unit 1 includes an adder 11. L Subtractor 12 L Delay circuit 13 L 14 FIR filters L and subtractor 15 L Furthermore, regarding the composition of the first spatial component sound signal for generating Rch, the spatial separation processing unit 1 includes an adder 11. R Subtractor 12 R Delay circuit 13 R 14 FIR filters R and subtractor 15 R .

[0028] Regarding the composition of the first spatial component sound signal that generates Lch (equivalent to one channel), the spatial separation processing unit 1 uses adder 11. L Subtractor 12 L The sum and difference signals of Lch and Rch are generated based on the input sound signals Lch and Rch. Additionally, the spatial separation processing unit 1 uses an FIR filter 14... L The input audio signal of Rch (equivalent to an input audio signal from outside one channel), the signal, and the difference signal are each filtered according to the first spatial component. Furthermore, a subtractor 15 is used... L From the FIR filter 14 L The processing time is coordinated by the delay circuit 13 L The delayed Lch input audio signal, minus the signal passed through FIR filter 14 L Multiple sound signals are then used to generate the first spatial component sound signal of Lch.

[0029] In Lch signal processing, filtering based on the first spatial component refers to using filter coefficients W, which are set for Lch based on the first spatial component. L1 W L2 W L3 To perform filtering. That is, FIR filter 14. L Using filter coefficients W L1 The input audio signal to Rch is filtered using filter coefficients W. L2 For adder 11 L The output signal is filtered using filter coefficients W. L3 For subtractor 12 L The output difference signal is filtered. Three filter coefficients W are used. L1 WL2 W L3 If used Figure 3 And then set up as described later.

[0030] Furthermore, regarding the composition of the first spatial component sound signal that generates Rch (equivalent to one channel), the spatial separation processing unit 1 uses adder 11. R and subtractor 12 R The sum and difference signals of Lch and Rch are generated based on the input sound signals Lch and Rch. Additionally, the spatial separation processing unit 1 uses an FIR filter 14... R The input audio signal of Lch (equivalent to an input audio signal from outside one channel), the signal, and the difference signal are each filtered according to the first spatial component. Furthermore, a subtractor 15 is used... R From FIR filter 14 R The processing time is coordinated by the delay circuit 13 R The delayed input audio signal of Rch, minus the signal passed through FIR filter 14 R Multiple sound signals are then used to generate the first spatial component sound signal of Rch.

[0031] In Rch signal processing, filtering based on the first spatial component refers to using filter coefficients W, which are set for Rch based on the first spatial component. R1 W R2 W R3 To perform filtering. That is, FIR filter 14. R Using filter coefficients W R1 The input audio signal of Lch is filtered using filter coefficients W. R2 For adder 11 R The output signal is filtered using filter coefficients W. R3 For subtractor 12 R The output difference signal is filtered. Three filter coefficients W are used. R1 W R2 W R3 If used Figure 3 And then set up as described later.

[0032] return Figure 1 Explanation follows. Delay circuit 3 (delay circuit 3 used in Lch) L Delay circuit 3 used with Rch R The input sound signals of the two channels are delayed in accordance with the processing time of the spatial separation processing unit 1.

[0033] The correction processing unit 4 performs arbitrary correction processing on the input sound signals of the two channels after passing through the delay circuit 3 and the spatial component sound signals of the two channels generated by the spatial separation processing unit 1 according to each of the first to Nth spatial components. The correction processing unit 4 can be configured, for example, by an equalizer that adjusts the sound quality by adding or subtracting specific frequency domains, a reverb circuit that imparts arbitrary sound effects, a bandpass filter, or a delay circuit. Alternatively, the correction processing unit 4 can be omitted.

[0034] Integrated Processing Unit 2 (Adder 2 for Lch) L Adder 2 used by Rch R The spatial component sound signals of the two channels are added to the input sound signals of the two channels by the spatial separation processing unit 1 according to each of the first to Nth spatial components. Figure 1 In the configuration example shown, the integration processing unit 2 adds the first to Nth spatial component sound signals of Lch, which has passed through the correction processing unit 4, to the input sound signal of Lch. Additionally, the first to Nth spatial component sound signals of Rch, which has passed through the correction processing unit 4, are added to the input sound signal of Rch, which has passed through the correction processing unit 4.

[0035] The correction processing unit 5 performs arbitrary correction processing on the input audio signals of the two channels after passing through the integration processing unit 2. The correction processing unit 5 can be configured, for example, by an equalizer, reverberation circuit, bandpass filter, or delay circuit. Alternatively, the correction processing unit 5 can be omitted.

[0036] Figure 3 It indicates that the calculation pair Figure 2 FIR filter 14 L 14 R The set filter coefficients W L1 W L2 W L3 W R1 W R2 W R3 A diagram illustrating an example configuration of the filter coefficient calculation circuit 20 is shown. It also shows the FIR filter 14 used to calculate the parameters for generating the first spatial component sound signal. L 14 R (Hereinafter referred to as the first spatial component FIR filter 14) L 14 R The filter coefficients W are set. L1 W L2 W L3 W R1 W R2 W R3 Example of its construction. Used to calculate the FIR filter for the second to Nth spatial components (in Figure 2 The composition of the filter coefficients (not shown in the figure) is also similar to... Figure 3 same.

[0037] like Figure 3 As shown, assume there are N virtual sound sources S1~S2 N Existing at any location in the virtual sound space, and originating from each virtual sound source S1~S N The output sound is produced by microphone 101 used by Lch, which is located in the same virtual sound space. L The microphone used by Rch 101 R Sound collection. Here, the sound emitted from the virtual sound source S1 is subject to the spatial transfer function C. 1L The influence reached the microphone 101 used by Lch. L And subject to the space transfer function C lR The influence reached the microphone 101 used by Rch. R These spatial transfer functions C can be pre-calculated. 1L C lR It is also possible to pre-calculate the signals from other virtual sound sources S2~S2. N To microphone 101 L 101 R The spatial transfer function.

[0038] like Figure 3 As shown, the filter coefficient calculation circuit 20 is configured to include a first signal processing unit 201, a second signal processing unit 202, and an error signal calculation unit 203. The first signal processing unit 201 calculates the filter coefficients from multiple virtual sound sources S1 to S2. N Input to microphone 101 L 101 R The virtual sound signals of the two channels are used to generate spatial component virtual sound signals of the two channels. The structure of the first signal processing unit 201 is similar to... Figure 2 The configuration of the space separation processing unit 1 shown is roughly the same. However, for Figure 2 The first spatial component FIR filter 14 shown L 14 R The filter coefficients are set to fixed values; the difference lies in that... Figure 3 The first spatial component FIR filter 24 shown L ,twenty four R It is constructed from an adaptive filter with variable filter coefficients. Hereinafter, it is denoted as an FIR adaptive filter 24. L ,twenty four R .

[0039] Regarding the composition of the virtual sound signal of the first spatial component generated by Lch, the first signal processing unit 201 includes an adder 21.L Subtractor 22 L Delay circuit 23 L 24 FIR adaptive filters L And subtractor 25 L As mentioned above, besides the FIR adaptive filter 24 L and Figure 2 FIR filter 14 L Aside from the differences, adder 21 L Subtractor 22 L Delay circuit 23 L And subtractor 25 L Is with Figure 2 Adder 11 L Subtractor 12 L Delay circuit 13 L and subtractor 15 L Same composition.

[0040] Furthermore, regarding the composition of the virtual sound signal of the first spatial component generated by Rch, the first signal processing unit 201 includes an adder 21. R Subtractor 22 R Delay circuit 23 R 24 FIR adaptive filters R And subtractor 25 R As mentioned above, besides the FIR adaptive filter 24 R and Figure 2 FIR filter 14 R Aside from the differences, adder 21 R Subtractor 22 R Delay circuit 23 R And subtractor 25 R Is with Figure 2 Adder 11 R Subtractor 12 R Delay circuit 13 R and subtractor 15 R Same composition.

[0041] The second signal processing unit 202 generates a signal from a virtual sound source (in... Figure 3 In the case of the first virtual sound source S1, the input is sent to the microphone 101. L 101 R Virtual sound signals from two channels. For example... Figure 3 As shown, the second signal processing unit 202 is configured to include an FIR filter 26. L 26 R and delay circuit 27 L 27 R The FIR filter 26L 26 R It was configured to install from the first virtual sound source S1 to the microphone 101 L 101 R Space transfer function C lL C 1R The filter coefficients.

[0042] Error signal calculation unit 203 calculates the error signal E between the spatial component virtual sound signal generated by the first signal processing unit 201 and the virtual sound signal from the virtual sound source S1 generated by the second signal processing unit 202. 1L E 1R The FIR adaptive filter 24 of the first signal processing unit 201 L ,twenty four R To make the error signal E 1L E 1R The error minimization method shown determines the filter coefficients for which the error is minimized. Furthermore, the filter coefficients determined in this way are set as follows: Figure 2 The first spatial component FIR filter 14 shown L 14 R filter coefficients W L1 W L2 W L3 W R1 W R2 W R3 .

[0043] That is, for Figure 2 The first spatial component FIR filter 14 of Lch shown L The set filter coefficients W L1 W L2 W L3 like Figure 3 The diagram shows the use of an FIR adaptive filter 24. L The coefficients determined by the FIR adaptive filter 24 L So that the input from the first virtual sound source S1 is to the microphone 101 L The virtual sound signal of Lch is based on multiple virtual sound sources S1~S N Input to microphone 101 L 101 R The coefficients are determined by minimizing the error between the virtual sound signals of the two channels and the spatial component virtual sound signals generated by Lch.

[0044] Similarly, for Figure 2 The first spatial component FIR filter 14 of Rch is shown. R The set filter coefficients W R1W R2 W R3 like Figure 3 As shown, using an FIR adaptive filter 24 R The coefficients determined by the FIR adaptive filter 24 R So that the input from the first virtual sound source S1 is to the microphone 101 R The virtual sound signal of Rch is based on multiple virtual sound sources S1~S N Input to microphone 101 L 101 R The coefficients are determined by minimizing the error between the virtual sound signals of the two channels and the spatial component virtual sound signals generated by Rch.

[0045] According to the audio signal processing device 10 of the first embodiment configured as described above, the integration processing unit 2 adds spatial component audio signals of the two channels generated by the spatial separation processing unit 1 according to each of the multiple spatial components to the input audio signals of the two channels. Therefore, the sound is emphasized according to each spatial component, and the sound effect of giving the listener spatial recognition of surround sound is achieved beyond that of the past.

[0046] (Modified example) Next, variations of the first embodiment will be described based on the accompanying drawings. Figure 4 This is a diagram illustrating a configuration example of the modified audio signal processing device 10A. Figure 4 In the middle, it is marked with Figure 1 The symbols shown have the same function for the same parts, so repeated descriptions are omitted here.

[0047] like Figure 4 As shown, the modified audio signal processing device 10A further includes a multi-channel processing unit 6. Additionally, the modified audio signal processing device 10A replaces... Figure 1 The integrated processing unit 2 and the correction processing units 4 and 5 shown are equipped with integrated processing unit 2A and correction processing units 4A and 5A.

[0048] The multi-channel processing unit 6 generates sound signals for other channels based on the input sound signals from the two channels. Figure 4 In the example shown, the multi-channel processing unit 6 uses the stereo sound signals of Lch and Rch to generate sound signals of Cch (center channel), LFE (subwoofer channel), LS (left surround channel) and RS (right surround channel).

[0049] As a method for generating surround sound signals for four channels in addition to the stereo sound signals of two channels, known methods can be used. For example, the multichannel processing unit 6 performs processing equivalent to the following operations using adders, subtractors, multipliers, and filters, thereby generating surround sound signals for four channels.

[0050] C = (L + R) / 2 LFE = LPF((L+R) / 2) LS = (LR) / 2 RS = (RL) / 2 The correction processing unit 4A performs arbitrary correction processing on the two-channel input sound signals after passing through the delay circuit 3, the four-channel surround sound signals generated by the multi-channel processing unit 6, and the two-channel spatial component sound signals generated by the spatial separation processing unit 1 according to each of the first to Nth spatial components. The correction processing unit 4A can be configured, for example, by an equalizer, reverberation circuit, bandpass filter, or delay circuit. Alternatively, the correction processing unit 4A can be omitted.

[0051] Integrated processing unit 2A is equipped with an adder 2 for Lch. L 2 adders used by Rch R Adder 2 used by Cch C Adder 2 used by LFEch LFE LSch uses adder 2 LS And adder 2 used by RSch RS Furthermore, the spatial component sound signals of the two channels are added to the input sound signals of the two channels and the surround sound signals of the four channels, and the spatial component sound signals of the two channels are generated by the spatial separation processing unit 1 according to each of the first to Nth spatial components.

[0052] exist Figure 4In the illustrated configuration example, the integration processing unit 2A adds the first to Nth spatial component sound signals of Lch (after passing through the correction processing unit 4A) to the input sound signal Lch (after passing through the correction processing unit 4A). Additionally, it adds the first to Nth spatial component sound signals of Rch (after passing through the correction processing unit 4A) to the input sound signal Rch (after passing through the correction processing unit 4A). Furthermore, it adds the first to Nth spatial component sound signals of Lch and Rch (after passing through the correction processing unit 4A) to the input sound signal Cch (after passing through the correction processing unit 4A). Additionally, it adds the first to Nth spatial component sound signals of Lch and Rch (after passing through the correction processing unit 4A) to the input sound signal LFEch (after passing through the correction processing unit 4A). Furthermore, it adds the first to Nth spatial component sound signals of Lch (after passing through the correction processing unit 4A) to the input sound signal LSch (after passing through the correction processing unit 4A). Finally, it adds the first to Nth spatial component sound signals of Rch (after passing through the correction processing unit 4A) to the input sound signal RSch (after passing through the correction processing unit 4A).

[0053] The correction processing unit 5A performs arbitrary correction processing on the input audio signals of the two channels and the surround sound signals of the four channels after passing through the integration processing unit 2A. The correction processing unit 5A can be configured, for example, by an equalizer, reverberation circuit, bandpass filter, or delay circuit. Alternatively, the correction processing unit 5A can be omitted.

[0054] like Figure 4 As shown in the modified example, by adding the two-channel input sound signals and the four-channel surround sound signals generated based on the input sound signals, along with the two-channel spatial component sound signals generated by the spatial separation processing unit 1 according to each of the multiple spatial components, it is possible to emphasize the total six-channel surround sound signal according to each spatial component. That is, Figure 1 The illustrated implementation can be extended to Figure 4 The multi-channel surround sound shown.

[0055] (Second Implementation) In the first embodiment and its variations, examples were described where the input audio signal to the audio signal processing apparatus 10, 10A was a two-channel stereo audio signal. In contrast, the second embodiment described below represents a configuration where the input audio signal is a four-channel (Lch, Rch, LSch, and RSch) surround sound signal. In the second embodiment, "four-channel surround sound signal" means the audio signals Lch, Rch, LSch, and RSch.

[0056] Figure 5 This is a diagram illustrating an example configuration of the audio signal processing device 10B according to the second embodiment. (See diagram below.) Figure 5As shown, the audio signal processing device 10B of the second embodiment is configured to include a spatial separation processing unit 1B, an integration processing unit 2B, a delay circuit 3B, correction processing units 4B and 5B, and a multi-channel processing unit 6B.

[0057] The spatial separation processing unit 1B generates spatial component sound signals according to the input sound signals of the four channels for each of the multiple spatial components corresponding to multiple virtual sound sources set at different spatial locations.

[0058] Figure 6 This is a diagram showing an example of the configuration of the space separation processing unit 1B. Figure 6 The diagram only illustrates the structure for generating the first spatial component sound signal, while the structures for generating the second to Nth spatial component sound signals are omitted. Except for the different filter coefficients used, the structures for generating the first to Nth spatial component sound signals are identical.

[0059] like Figure 6 As shown, the spatial separation processing unit 1B generates a first spatial component sound signal for the four channels based on the input sound signals from the four channels. Here, when generating the spatial component sound signal for one of the four channels, the input sound signals from the three channels including that channel are used to generate the spatial component sound signal. Of the three input sound signals, the input sound signals from the two channels other than the first channel are the input sound signals from two channels that are adjacent to the first channel.

[0060] Based on such Figure 7 The typical arrangement of the surround speakers determines the channel adjacency. Specifically, if one channel is LSch, the other two channels are Lch and RSch, which are adjacent to LSch. If one channel is Lch, the other two channels are Rch and LSch, which are adjacent to Lch. If one channel is Rch, the other two channels are Lch and RSch, which are adjacent to Rch. If one channel is RSch, the other two channels are Rch and LSch, which are adjacent to RSch.

[0061] For example, the spatial separation processing unit 1B generates a first spatial component sound signal of LSch based on the input sound signals from the three channels LSch, Lch, and RSch. The composition of the generated first spatial component sound signal of LSch is as follows: Figure 6 As shown, the space separation processing unit 1B includes an adder 31. LS 32 LS Subtractor 33 LS34 LS Delay circuit 35 LS 36 FIR filters LS and subtractor 37 LS .

[0062] Regarding the composition of the first spatial component sound signal for generating LSch (equivalent to one channel), the spatial separation processing section 1B uses adder 31. LS Subtractor 33 LS The sum and difference signals of LSch and Lch are generated based on the input sound signals LSch and Lch, and then passed through adder 32. LS Subtractor 34 LS The sum and difference signals of LSch and RSch are generated based on the input audio signals LSch and RSch. Additionally, the spatial separation processing unit 1B uses an FIR filter 36... LS The input audio signals Lch and RSch (equivalent to input audio signals other than one channel), the signal, and the difference signal are respectively filtered according to the first spatial component. Furthermore, subtractor 37... LS From the FIR filter 36 LS The processing time is coordinated by the delay circuit 35 LS The delayed input audio signal of LSch, minus the signal passed through the FIR filter 36 LS Multiple sound signals are then used to generate the first spatial component sound signal of LSch.

[0063] In LSch signal processing, filtering based on the first spatial component refers to using filter coefficients W, which are set according to the first spatial component for LSch. LS1 ~W LS6 To perform filtering. That is, FIR filter 36. LS Using filter coefficients W LS1 The input audio signal of Lch is filtered using filter coefficients W. LS2 For adder 31 LS The output signal is filtered using filter coefficients W. LS3 For subtractor 33 LS The output difference signal is filtered using filter coefficients W. LS4 The input audio signal of RSch is filtered using filter coefficients W. LS5 For adder 32 LS The output signal is filtered using filter coefficients W. LS6 For subtractor 34 LS The output difference signal is filtered. There are 6 filter coefficients W. LS1 ~WLS6 If used Figure 8A As described later.

[0064] Furthermore, the spatial separation processing unit 1B generates the first spatial component sound signal of Lch based on the input sound signals from the three channels Lch, Rch, and LSch. Regarding the composition of the first spatial component sound signal for generating Rch, as follows... Figure 6 As shown, the space separation processing unit 1B includes an adder 31. L 32 L Subtractor 33 L 34 L Delay circuit 35 L 36 FIR filters L and subtractor 37 L .

[0065] Regarding the composition of the first spatial component sound signal that generates Lch (equivalent to one channel), the spatial separation processing unit 1B uses adder 31. L Subtractor 33 L The sum and difference signals of Lch and LSch are generated based on the input sound signals Lch and LSch, and then passed through adder 32. L Subtractor 34 L The sum and difference signals of Lch and Rch are generated based on the input sound signals Lch and Rch. Additionally, the spatial separation processing unit 1B uses an FIR filter 36... L The input audio signals LSch and Rch (equivalent to input audio signals other than one channel), the signal, and the difference signal are respectively filtered according to the first spatial component. Furthermore, subtractor 37... L From the FIR filter 36 L The processing time is coordinated by the delay circuit 35 L The delayed Lch input audio signal, minus the signal passed through the FIR filter 36 L Multiple sound signals are then used to generate the first spatial component sound signal of Lch.

[0066] In signal processing, Lch filtering based on the first spatial component refers to using filter coefficients W, which are set according to the first spatial component and used in Lch. L1 ~W L6 To perform filtering. That is, FIR filter 36. L Using filter coefficients W L1 The input audio signal of LSch is filtered using filter coefficients W. L2 For adder 31 L The output signal is filtered using filter coefficients W.L3 For subtractor 33 L The output difference signal is filtered using filter coefficients W. L4 The input audio signal to Rch is filtered using filter coefficients W. L5 For adder 32 L The output signal is filtered using filter coefficients W. L6 For subtractor 34 L The output difference signal is filtered. There are 6 filter coefficients W. L1 ~W L6 If used Figure 8A As described later.

[0067] Furthermore, the spatial separation processing unit 1B generates a first spatial component sound signal for Rch based on the input sound signals from the three channels Rch, Lch, and RSch. The composition of the generated first spatial component sound signal for Rch is as follows: Figure 6 As shown, the space separation processing unit 1B includes an adder 31. R 32 R Subtractor 33 R 34 R Delay circuit 35 R 36 FIR filters R and subtractor 37 R .

[0068] Regarding the composition of the first spatial component sound signal that generates Rch (equivalent to one channel), the spatial separation processing unit 1B uses adder 31. R Subtractor 33 R The sum and difference signals of Rch and RSch are generated based on the input sound signals Rch and RSch, and then passed through adder 32. R Subtractor 34 R The sum and difference signals of Rch and Lch are generated based on the input sound signals Rch and Lch. Additionally, the spatial separation processing unit 1B uses an FIR filter 36... R The input audio signals Lch and RSch (equivalent to input audio signals other than one channel), the signal, and the difference signal are respectively filtered according to the first spatial component. Furthermore, subtractor 37... R From the FIR filter 36 R The processing time is coordinated by the delay circuit 35 R The delayed input audio signal of Rch, minus the signal passed through the FIR filter 36 R Multiple sound signals are then used to generate the first spatial component sound signal of Rch.

[0069] In Rch signal processing, filtering based on the first spatial component refers to using filter coefficients W, which are set according to the first spatial component for Rch. R1 ~W R6 To perform filtering. That is, FIR filter 36. R Using filter coefficients W R1 The input audio signal of RSch is filtered using filter coefficients W. R2 For adder 31 R The output signal is filtered using filter coefficients W. R3 For subtractor 33 R The output difference signal is filtered using filter coefficients W. R4 The input audio signal of Lch is filtered using filter coefficients W. R5 For adder 32 R The output signal is filtered using filter coefficients W. R6 For subtractor 34 R The output difference signal is filtered. There are 6 filter coefficients W. R1 ~W R6 If used Figure 8B As described later.

[0070] Furthermore, the spatial separation processing unit 1B generates a first spatial component sound signal for RSch based on the input sound signals from the three channels RSch, Rch, and LSch. The composition of the generated first spatial component sound signal for RSch is as follows: Figure 6 As shown, the space separation processing unit 1B includes an adder 31. RS 32 RS Subtractor 33 RS 34 RS Delay circuit 35 RS 36 FIR filters RS and subtractor 37 RS .

[0071] Regarding the composition of the first spatial component sound signal for generating RSch (equivalent to one channel), the spatial separation processing section 1B uses adder 31. RS Subtractor 33 RS The sum and difference signals of RSch and Rch are generated based on the input sound signals RSch and Rch, and then passed through adder 32. RS Subtractor 34 RS The sum and difference signals of RSch and LSch are generated based on the input audio signals RSch and LSch. Additionally, the spatial separation processing unit 1B uses an FIR filter 36... RSThe input audio signals LSch and Rch (equivalent to input audio signals other than one channel), the signal, and the difference signal are respectively filtered according to the first spatial component. Furthermore, subtractor 37... RS From the FIR filter 36 RS The processing time is coordinated by the delay circuit 35 RS The delayed input audio signal of RSch, minus the signal passed through the FIR filter 36 RS Multiple sound signals are then used to generate the first spatial component sound signal of RSch.

[0072] In RSch signal processing, filtering based on the first spatial component refers to using filter coefficients W, which are set according to the first spatial component for RSch. RS1 ~W RS6 To perform filtering. That is, FIR filter 36. RS Using filter coefficients W RS1 The input audio signal to Rch is filtered using filter coefficients W. RS2 For adder 31 RS The output signal is filtered using filter coefficients W. RS3 For subtractor 33 RS The output difference signal is filtered using filter coefficients W. RS4 The input audio signal of LSch is filtered using filter coefficients W. RS5 For adder 32 RS The output signal is filtered using filter coefficients W. RS6 For subtractor 34 RS The output difference signal is filtered. There are 6 filter coefficients W. RS1 ~W RS6 If used Figure 8B As described later.

[0073] return Figure 5 The delay circuit 3B delays the input audio signals of the four channels in coordination with the processing time of the spatial separation processing unit 1B.

[0074] The multi-channel processing unit 6B generates sound signals for all other channels based on the input sound signals for the four channels. Figure 5 In the example shown, the multichannel processing unit 6B uses four input audio signals to generate audio signals for Cch (center channel), LFE (subwoofer channel), LBS (rear left channel), RBS (rear right channel), and BS (rear center channel). Alternatively, the multichannel processing unit 6B can be omitted.

[0075] As a method for generating a surround sound signal with five channels in addition to the four-channel input sound signal, a known method can be used. For example, the multichannel processing unit 6B can generate a five-channel surround sound signal by performing operations equivalent to the following using adders, subtractors, multipliers, and filters.

[0076] C = (L + R) / 2 LFE = LPF((L+R) / 2) LBS = (LS - R) / 2 RBS = (RS - L) / 2 BS = (LBS + RBS) / 2 The correction processing unit 4B performs arbitrary correction processing on the nine-channel audio signals after passing through the multi-channel processing unit 6B and the four-channel spatial component audio signals generated by the spatial separation processing unit 1B according to each of the first to Nth spatial components. The correction processing unit 4B can be configured, for example, by an equalizer, reverberation circuit, bandpass filter, or delay circuit. Alternatively, the correction processing unit 4B can be omitted.

[0077] The integration processing unit 2B adds four spatial component sound signals generated by the spatial separation processing unit 1B according to each of the first to Nth spatial components to the nine-channel sound signals after passing through the correction processing unit 4B. Figure 5 In the illustrated configuration example, the integrated processing unit 2B adds the first to Nth spatial component sound signals of Lch to the Lch sound signal. Additionally, it adds the first to Nth spatial component sound signals of Rch to the Rch sound signal. Furthermore, it adds the first to Nth spatial component sound signals of Lch and Rch to the Cch sound signal. Additionally, it adds the first to Nth spatial component sound signals of Lch and Rch to the LFEch sound signal. Additionally, it adds the first to Nth spatial component sound signals of LSch and Lch to the LSch sound signal. Additionally, it adds the first to Nth spatial component sound signals of RSch and Rch to the RSch sound signal. Additionally, it adds the first to Nth spatial component sound signals of LSch to the LBSch sound signal. Additionally, it adds the first to Nth spatial component sound signals of RSch to the RBSch sound signal. Finally, it adds the first to Nth spatial component sound signals of LSch and RSch to the BSch sound signal.

[0078] The correction processing unit 5B performs arbitrary correction processing on the nine-channel audio signals after passing through the integration processing unit 2B. The correction processing unit 5B can be configured, for example, by an equalizer, reverberation circuit, bandpass filter, or delay circuit. Alternatively, the correction processing unit 5B can be omitted.

[0079] Figure 8A and Figure 8B It indicates that the calculation pair Figure 6 FIR filter 36 LS 36 L 36 R 36 RS The set filter coefficients W LS1 ~W LS6 W L1 ~W L6 W R1 ~W R6 W RS1 ~W RS6 A diagram illustrating an example configuration of the filter coefficient calculation circuit 20B. Figure 8A and Figure 8B This indicates the FIR filter 36 used for calculating the sound signal of the first spatial component. LS 36 L 36 R 36 RS The filter coefficients W (hereinafter referred to as the first spatial component FIR filter 36) are set. LS1 ~W LS6 W L1 ~W L6 W R1 ~W R6 W RS1 ~W RS6 Example of its construction. Used to calculate the FIR filter for the second to Nth spatial components (in Figure 5 The composition of the filter coefficients (not shown in the figure) is also similar to... Figure 8A as well as Figure 8B same.

[0080] like Figure 8A and Figure 8B As shown, the filter coefficient calculation circuit 20B is configured to include a first signal processing unit 201. LS 201 L 201 R 201 RS Second Signal Processing Unit 202 LS 202 L 202 R 202 RS and error signal calculation unit 203 LS 203 L 203 R 203 RS .

[0081] First Signal Processing Unit 201 LS Second Signal Processing Unit 202 LSError signal calculation unit 203 LS Based on multiple virtual sound sources S1~S N Input to microphone 101 LS 101 L 101 R 101 RS The four channels of virtual sound signals are used to generate the spatial component virtual sound signal of LSch.

[0082] First Signal Processing Unit 201 L Second Signal Processing Unit 202 L Error signal calculation unit 203 L Based on multiple virtual sound sources S1~S N Input to microphone 101 LS 101 L 101 R 101 RS The four channels of virtual sound signals are used to generate the spatial component virtual sound signal of Lch.

[0083] First Signal Processing Unit 201 R Second Signal Processing Unit 202 R Error signal calculation unit 203 R Based on multiple virtual sound sources S1~S N Input to microphone 101 LS 101 L 101 R 101 RS The four channels of virtual sound signals are used to generate the spatial component virtual sound signal of Rch.

[0084] First Signal Processing Unit 201 RS Second Signal Processing Unit 202 RS Error signal calculation unit 203 RS Based on multiple virtual sound sources S1~S N Input to microphone 101 LS 101 L 101 R 101 RS The four channels of virtual sound signals are used to generate the spatial component virtual sound signal of RSch.

[0085] The following explanation uses the generation of the spatial component virtual sound signal of LSch as an example, but the generation of other spatial component virtual sound signals of Lch, Rch, and RSch is the same.

[0086] First Signal Processing Unit 201 LS The composition and in Figure 6The spatial separation processing unit 1B shown has a largely similar structure for generating the first spatial component sound signal of LSch. However, the difference lies in the fact that, relative to the... Figure 6 The first spatial component FIR filter 36 shown LS Set fixed values ​​for the filter coefficients. Figure 8A The first spatial component FIR filter 46 shown LS It is constructed from an adaptive filter with variable filter coefficients. Hereinafter, it is denoted as an FIR adaptive filter 46. LS .

[0087] First Signal Processing Unit 201 LS Equipped with adder 41 LS 42 LS Subtractor 43 LS 44 LS Delay circuit 45 LS 46 FIR adaptive filters LS Subtractor 47 LS As mentioned above, besides the FIR adaptive filter 46 LS and Figure 6 FIR filter 36 LS Aside from the differences, adder 41 LS 42 LS Subtractor 43 LS 44 LS Delay circuit 45 LS And subtractor 47 LS Is with Figure 6 Adder 31 LS 32 LS Subtractor 43 LS 44 LS Delay circuit 45 LS and subtractor 47 LS Same composition.

[0088] Second Signal Processing Unit 202 LS Generate from a virtual sound source (in Figure 8A In the case of the first virtual sound source S1, the signal is directed to the microphone 101. LS The input LS channel virtual audio signal. For example... Figure 8A As shown, the second signal processing unit 202 LS It is configured to have an FIR filter 48 LS and delay circuit 49 LS The FIR filter has 48 LS It was configured to install from the first virtual sound source S1 to the microphone 101 LS Space transfer function C lLS The filter coefficients.

[0089] Error Signal Calculator 203 LS The calculation is performed by the first signal processing unit 201 LS The generated spatial component virtual sound signal and the signal generated by the second signal processing unit 202 LS The error signal E between the generated virtual sound signals from virtual sound source S1 and LSch 1LS First Signal Processing Unit 201 LS FIR adaptive filter 46 LS So that the error signal E 1LS The process involves minimizing the error as shown, determining the filter coefficients whose error is minimized. Furthermore, these determined filter coefficients are set to... Figure 6 The first spatial component FIR filter 36 shown LS filter coefficients W LS1 ~W LS6 .

[0090] That is, for Figure 6 The first spatial component FIR filter 64 of the LSch shown LS The set filter coefficients W LS1 ~W LS6 like Figure 8A As shown, using an FIR adaptive filter 46 LS The coefficients determined by the FIR adaptive filter 46 LS So that the input from the first virtual sound source S1 is to the microphone 101 LS The virtual sound signal of LSch is based on multiple virtual sound sources S1~S N Input to microphone 101 LS 101 L 101 R 101 RS The coefficients are determined by minimizing the error between the four channels of the virtual sound signal and the spatial component virtual sound signal generated by LSch.

[0091] The audio signal processing device 10B according to the second embodiment configured as described above can achieve a further expansion to multi-channel surround sound than the modified example described above. That is, when there are more input audio signals than two channels, the integration processing unit 2B adds the spatial component audio signals of each channel generated by the spatial separation processing unit 1B according to each of the multiple spatial components to the input audio signals of each channel. Therefore, by emphasizing the sound according to each spatial component, it is possible to achieve an audio effect that provides the listener with spatial recognition of surround sound beyond the past.

[0092] Furthermore, in the second embodiment, an example is described where the input audio signal is four channels, and when generating the spatial component audio signal for one of the channels, the spatial component audio signal is generated using the input audio signals of the three channels including that one channel, and the input audio signals of the two channels adjacent to that one channel are used as the input audio signals for the other two channels. However, the invention is not limited to this. For example, when generating the spatial component audio signal for one channel, the spatial component audio signal may be generated using the input audio signals of all four channels, and the input audio signals of the three channels other than that one channel may be used as the input audio signals for the other two channels.

[0093] If spatial component sound signals are generated using all four channels of input sound signals, then by adding spatial component sound signals that reflect the acoustic characteristics of all channels of input sound signals, sound emphasis can be applied to each spatial component. Furthermore, even when using three channels of input sound signals (one less channel) to generate spatial component sound signals as in the second embodiment, since spatial component sound signals are generated using input sound signals from one channel and two adjacent channels relative to that channel, the following advantages are also present: sound emphasis can be applied to each spatial component by adding spatial component sound signals that reflect the acoustic characteristics that have a greater influence on that channel, and the increase in circuit size can be suppressed.

[0094] Furthermore, in the second embodiment, an example was described where a four-channel audio signal consisting of Lch, Rch, LSch, and RSch was input to the audio signal processing device 10B; however, the input audio signal is not limited to this. For example, the multi-channel processing unit 6B may be omitted, and a nine-channel audio signal may be input.

[0095] The configuration of the spatial separation processing units 1 and 1B shown in the various embodiments and variations described herein is an example and is not limited thereto. That is, in the spatial separation processing units 1 and 1B, the sound signal generated by adding or subtracting the sound signals of each channel is filtered, but the method of addition and subtraction may, for example, be different from the example described.

[0096] In addition, the following are examples of structures that can be applied to the content of this disclosure.

[0097] [Component 1] An audio signal processing device, characterized in that it comprises: The spatial separation processing unit generates spatial component sound signals based on the input sound signals from multiple channels, according to each of the multiple spatial components corresponding to multiple virtual sound sources set at different spatial locations; and The integration processing unit adds the spatial component sound signals of the multiple channels generated by the spatial separation processing unit according to each of the multiple spatial components to the input sound signals of the multiple channels.

[0098] [Component 2] The audio signal processing apparatus according to configuration 1 is characterized in that, The spatial separation processing unit generates a sum signal and a difference signal for the multiple channels based on the input sound signals of the multiple channels. It subtracts multiple sound signals, after filtering based on spatial components on the input sound signals (excluding one channel), the sum signal, and the difference signal, from the input sound signal of the one channel, thereby generating the spatial component sound signal of the one channel.

[0099] [Component 3] The audio signal processing apparatus according to configuration 2 is characterized in that, As filter coefficients for the filtering process, coefficients determined by an adaptive filter are used, which determines the coefficients in a manner that minimizes the error between the virtual sound signal of the one channel input from a virtual sound source and the spatial component virtual sound signal generated for the one channel based on the virtual sound signals of the multiple channels input from the plurality of virtual sound sources.

[0100] [Composition 4] The audio signal processing apparatus according to any one of configurations 1 to 3 is characterized in that, The input audio signal for the multiple channels is a stereo audio signal for two channels.

[0101] [Component 5] The audio signal processing apparatus according to any one of configurations 1 to 3 is characterized in that, The input sound signals for the multiple channels are surround sound signals for four channels.

[0102] [Composition 6] The audio signal processing apparatus according to configuration 2 or configuration 3 is characterized in that, The input sound signals for the multiple channels are four-channel surround sound signals. The input sound signal other than the one channel refers to the input sound signal of the two channels other than the one channel, and the input sound signal of the two channels is the input sound signal of the two channels that are adjacent to the one channel.

[0103] [Component 7] The audio signal processing apparatus according to configuration 2 or configuration 3 is characterized in that, The input sound signals for the multiple channels are four-channel surround sound signals. The input audio signal other than the one channel refers to the input audio signal of the three channels other than the one channel.

[0104] [Composition 8] The audio signal processing apparatus according to any one of configurations 1 to 7 is characterized in that, It also includes a multi-channel processing unit that generates audio signals for other channels based on the input audio signals from the multiple channels. The integration processing unit takes the input sound signals of the multiple channels and the sound signals of the other channels generated by the multichannel processing unit, and adds the spatial component sound signals of the multiple channels generated by the spatial separation processing unit according to each of the multiple spatial components.

[0105] Furthermore, the embodiments described are merely illustrative examples of implementing this disclosure and should not be construed as limiting the technical scope of this disclosure. That is, this disclosure can be implemented in various forms without departing from its spirit or main features.

Claims

1. An audio signal processing device, characterized in that, have: The spatial separation processing unit generates spatial component sound signals according to the input sound signals from multiple channels for each of the multiple spatial components corresponding to multiple virtual sound sources set at different spatial locations. as well as The integration processing unit adds the spatial component sound signals of the multiple channels generated by the spatial separation processing unit according to each of the multiple spatial components to the input sound signals of the multiple channels.

2. The audio signal processing device according to claim 1, characterized in that, The spatial separation processing unit generates a sum signal and a difference signal for the multiple channels based on the input sound signals of the multiple channels. It subtracts multiple sound signals, after filtering based on spatial components on the input sound signals (excluding one channel), the sum signal, and the difference signal, from the input sound signal of the one channel, thereby generating the spatial component sound signal of the one channel.

3. The audio signal processing device according to claim 2, characterized in that, As filter coefficients for the filtering process, coefficients determined by an adaptive filter are used, which determines the coefficients in a manner that minimizes the error between the virtual sound signal of the one channel input from a virtual sound source and the spatial component virtual sound signal generated for the one channel based on the virtual sound signals of the multiple channels input from the plurality of virtual sound sources.

4. The audio signal processing device according to any one of claims 1 to 3, characterized in that, The input audio signal for the multiple channels is a stereo audio signal for two channels.

5. The audio signal processing apparatus according to any one of claims 1 to 3, characterized in that, The input sound signals for the multiple channels are surround sound signals for four channels.

6. The audio signal processing device according to claim 2 or 3, characterized in that, The input sound signals for the multiple channels are four-channel surround sound signals. The input sound signal other than the one channel refers to the input sound signal of the two channels other than the one channel, and the input sound signal of the two channels is the input sound signal of the two channels that are adjacent to the one channel.

7. The audio signal processing device according to claim 2 or 3, characterized in that, The input sound signals for the multiple channels are four-channel surround sound signals. The input audio signal other than the one channel refers to the input audio signal of the three channels other than the one channel.

8. The audio signal processing apparatus according to any one of claims 1 to 3, characterized in that, It also includes a multi-channel processing unit that generates audio signals for other channels based on the input audio signals from the multiple channels. The integration processing unit takes the input sound signals of the multiple channels and the sound signals of the other channels generated by the multichannel processing unit, and adds the spatial component sound signals of the multiple channels generated by the spatial separation processing unit according to each of the multiple spatial components.

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