In-vehicle sound field zoning control method and system considering spatial consistency

Abstract

The present invention discloses a method and system for controlling the zoning of the sound field in a vehicle considering spatial consistency, which comprises the following steps: Step 1: measuring the transfer function H from the loudspeaker array to the microphone array in different areas of the vehicle; i (f); Step 2: Divide the car's interior sound field into several bright areas and several dark areas according to actual needs, and determine the transfer function H from the loudspeaker array to the microphone array in the bright area based on the measurement results of step 1. B (f) Transfer function H from the loudspeaker array to the microphone array in the dark area D (f) Determine the target sound field P that is expected to be reconstructed in the bright area BT (f); Step 3, based on H B (f), H D (f), P BT (f) A sound field zoning control model that considers spatial consistency is constructed. The corresponding generalized Lagrangian penalty function F(f) is determined, and the speaker array excitation signal q(f) is obtained by solving the equation #imgabs0#. This improves the spatial consistency of the control area while adjusting the acoustic energy contrast between bright and dark areas and the reconstruction accuracy of the bright area.

Description

Technical Field

[0001] The present invention relates to the field of in-vehicle sound control, and in particular to an in-vehicle sound field zoning control method and system taking spatial consistency into consideration. Background Art

[0002] In recent years, as sound is a key means of communication in smart cockpits, research on personalized sound experiences, including sound field zoning, has garnered significant attention from academics and automakers. Sound field zoning aims to create distinct sound fields in different areas without interfering with each other, providing customers with a private, personalized, localized sound space. The area where a specific sound field needs to be recreated is defined as a bright zone, while other areas are defined as a dark zone.

[0003] There are currently two main methods for achieving sound field zoning: 1) The sound field zoning of the car cabin is achieved based on the strong directivity of parametric array speakers. 2) Based on algorithms such as PM (Pressure Matching) and ACC (Acoustic Contrast Control), the sound field zoning of the car cabin is achieved by using a speaker array to emit superposition sounds. Based on the nonlinear effect of ultrasonic carrier propagation in the air medium, parametric array speakers can achieve strong directivity, but are prone to harmonic distortion during the demodulation process, resulting in poor accuracy in bright area reconstruction. When using a speaker array to emit superposition sounds to achieve sound field zoning based on algorithms such as PM and ACC, the contrast between the sound energy in the bright and dark areas and the accuracy of bright area reconstruction can be adjusted, but the problem of spatial consistency within the area is not considered. If perceptible sound pressure level fluctuations occur at different locations within the area, it will affect the passengers' sound field zoning experience.

[0004] CN114827837A discloses a sound field zoning control method for maximizing sound energy contrast under reconstruction error constraints. By giving a given allowable reconstruction sound field error, a coordinate descent algorithm is used to solve the loudspeaker array filter. This method does not require manual parameter adjustment and can maximize the sound energy contrast as much as possible under a given reconstruction error. However, it does not consider the issue of spatial consistency within the region.

[0005] CN110446136B discloses a control method for a vehicle interior sound field zoning reconstruction system, which uses a virtual sound source to generate a bright area sound field control signal, and proposes a control method for independent and non-linked switching of bright and dark areas, thereby ensuring a stereo effect in the bright area and realizing independent and non-linked switching of bright and dark areas. However, the problem of spatial consistency within the area is not considered. Summary of the Invention

[0006] The purpose of the present invention is to provide a method and system for controlling the zoning of the in-vehicle sound field taking into account spatial consistency, which can improve the spatial consistency of the control area while adjusting the sound energy contrast between bright and dark areas and the reconstruction accuracy of the bright area.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A method for controlling the zoning of the vehicle interior sound field taking into account spatial consistency comprises the following steps:

[0009] Step 1: Measure the transfer function H from the speaker array to the microphone array in different areas of the car. i (f);

[0010] Step 2: Divide the car's interior sound field into several bright areas and several dark areas according to actual needs, and determine the transfer function H from the speaker array to the microphone array in the bright area based on the measurement results of step 1. B (f) Transfer function H from the loudspeaker array to the microphone array in the dark area D (f) Determine the target sound field P that is expected to be reconstructed in the bright area BT (f);

[0011] Step 3: Based on H B (f), H D (f), P BT (f) Construct a sound field partition control model considering spatial consistency, determine the generalized Lagrangian penalty function F(f) corresponding to the sound field partition control model, and the speaker array excitation signal q(f) is obtained by solving the equation The optimal solution is obtained.

[0012] Furthermore, the sound field partition control model considering spatial consistency in step 3 is:

[0013] st||P B (f)-P BT (f)|| 2 ≤K1,||q(f)|| 2 ≤K2,||C(f)|| 2 ≤K3;

[0014] Where, P D (f) = H D (f)q(f) is the reconstructed sound field in the dark area, and q(f) is the speaker array excitation signal;

[0015] P B (f) = H B (f)q(f) is the reconstructed sound field in the bright area, K1 is the constraint condition for the reconstruction accuracy of the bright area, and K2 is the constraint condition for the speaker array power;

[0016] C(f)=[H B (f)-h B (f)]q(f) is the spatial consistency parameter of the bright area, h B(f) is the mean value of the transfer function from the loudspeaker array to the microphone array in the bright area, and K3 is the constraint condition for spatial consistency in the bright area;

[0017] The generalized Lagrangian penalty function F(f) corresponding to the sound field partition control model is:

[0018] F(f)=λ1(f)||P D (f)|| 2 +λ2(f)(||P B (f)-P BT (f)|| 2 -K1)+λ3(f)(||q(f)|| 2 -K2)+λ4(f)(||C(f)|| 2 -K3),

[0019] Where λ1(f), λ2(f), λ3(f), and λ4(f) are weight factors, all of which are ≥0;

[0020] Furthermore, step 1 is specifically as follows: by giving the speaker array a white noise excitation signal w l (t), the acoustic signals S collected by the microphone array in different areas of the car mli (t) calculated;

[0021]

[0022] Where H i (f) is the transfer function matrix from the loudspeaker array to the microphone array in the i-th control area, i = {1, 2, ..., N}, N is the number of control areas; l = {1, 2, ..., L}, L is the number of loudspeakers; m = {1, 2, ..., M}, M is the number of microphones in the i-th control area; h mli (f) is the transfer function from the lth loudspeaker to the mth microphone in the i-th control area; S mli (f) is the acoustic signal S collected by the mth microphone in the i-th control area mli (t) and the white noise excitation signal w of the l-th speaker l The cross power spectral density of (t); S ll (f) is the white noise excitation signal w of the lth speaker l (t); f is the frequency domain and t is the time domain.

[0023] Furthermore, in step 2, the in-car sound field includes the driver area, the co-pilot area, the rear left passenger area, and the rear right passenger area.

[0024] A vehicle interior sound field zoning control system that takes spatial consistency into consideration can implement the vehicle interior sound field zoning control method that takes spatial consistency into consideration described in the present invention, comprising a sound field zoning control algorithm integration unit, a digital-to-analog converter, a power amplifier, a speaker array, and a microphone array for collecting vehicle interior sound signals. The sound field zoning control algorithm integration unit calculates a speaker array excitation signal based on the divided bright and dark areas and the target sound field to be reconstructed in the bright area. The speaker array excitation signal is transmitted to the speaker array through the digital-to-analog converter and the power amplifier, and the speaker array finally emits sound.

[0025] Beneficial effects of the present invention: The present invention divides the sound field in the car into several bright areas and several dark areas according to actual needs, and based on the transfer function H from the speaker array to the microphone array in the bright area B (f) Transfer function H from the loudspeaker array to the microphone array in the dark area D (f), and the target sound field PBT(f) that is expected to be reconstructed in the bright area, a sound field partition control model considering spatial consistency is constructed. The sound field partition control model is used to constrain the sound pressure difference at different positions in the bright area, thereby achieving adjustable sound energy contrast between bright and dark areas and the reconstruction accuracy of the bright area, while improving the spatial consistency of the control area. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of the vehicle interior sound field partition control method considering spatial consistency according to the present invention;

[0027] Figure 2 Schematic diagram of the structure of the sound field partition control system considering spatial consistency according to the present invention;

[0028] Figure 3 This is a schematic diagram of the layout of a single-zone microphone array in a car cabin;

[0029] Figure 4 This is a diagram of the speaker array layout in a car cabin;

[0030] Figure 5 This is a schematic diagram comparing the spatial consistency of different control methods in a car cockpit.

[0031] In the figure, 1 is the sound field partition control algorithm integrated unit, 2 is the digital-to-analog converter, 3 is the power amplifier, 4 is the speaker array, and 5 is the microphone array. DETAILED DESCRIPTION

[0032] The following describes the embodiments of the present invention with reference to the accompanying drawings and preferred embodiments. Those skilled in the art will readily appreciate the other advantages and benefits of the present invention from the disclosure herein. The present invention may also be implemented or applied through various other specific embodiments, and the various details in this specification may be modified or altered based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are intended only to illustrate the present invention and are not intended to limit the scope of protection of the present invention.

[0033] It should be noted that the illustrations provided in the following embodiments are merely schematic illustrations of the basic concept of the present invention. Therefore, the illustrations only show components related to the present invention and are not drawn according to the number, shape, and size of components in actual implementation. In actual implementation, the type, quantity, and proportion of each component may be changed arbitrarily, and the component layout may also be more complex.

[0034] Taking the realization of four-zone sound field zoning control in a certain car cockpit as an example, a sound field zoning control system with four-zone sound field in the car cockpit considering spatial consistency is established. Figure 2 The sound field zoning control system considering spatial consistency shown in the figure includes a sound field zoning control algorithm integration unit 1, a digital-to-analog converter 2, a power amplifier 3, a speaker array 4, and a microphone array 5 for collecting sound signals inside the car. The sound field zoning control algorithm integration unit 1 calculates the speaker array excitation signal based on the divided bright and dark areas and the target sound field to be reconstructed in the bright area. The speaker array excitation signal is transmitted to the speaker array 4 through the digital-to-analog converter 2 and the power amplifier 3, and finally the speaker array 4 emits sound to achieve the reconstruction of the target sound field in the bright area and reduce the sound energy as much as possible in the dark area. The microphone array 5 is used to collect sound signals inside the car and is only used when measuring the transfer function from the speaker array 4 to the microphone array 5 and detecting the zoning control effect. In this specific example, there are four sound field zoning control areas in the car cabin, including the driver area, the co-pilot area, the rear left passenger area, and the rear right passenger area. The navigation sound is played at the driver's position and is set as the bright area; the co-pilot, rear left passenger, and rear right passenger areas remain quiet and are set as the dark area. See Figure 3 The specific arrangement of the microphone array 4 is as follows: the number of microphones in each control area is set to 24, distributed in two layers, arranged in the passenger head area, with 12 microphones in each layer, evenly distributed on a circle with a diameter D of 16 cm, and the height difference d between the upper and lower layers is 8 cm. Figure 4 ,The number of speakers in the speaker array 5 is set to 8, which are arranged on the top of the car cabin.

[0035] In this specific example, a method for controlling the vehicle interior sound field partitioning taking into account spatial consistency is adopted, which includes the following steps:

[0036] Step 1: Measure the transfer function H from the speaker array to the four-zone microphone array in the car. i (f); obtain the transfer function H1(f) from the speaker array to the microphone array in the driver area, the transfer function H2(f) from the speaker array to the microphone array in the co-pilot area, the transfer function H3(f) from the speaker array to the microphone array in the rear left passenger area, and the transfer function H4(f) from the speaker array to the microphone array in the rear right passenger area. Specifically, by giving the speaker array a white noise excitation signal wl(t), the acoustic signals S of the four regional microphone arrays in the car are collected. m li(t) is calculated;

[0037]

[0038] Where H i (f) is the transfer function matrix from the loudspeaker array to the microphone array in the i-th control area, i = {1, 2, ..., N}, N is the number of control areas; l = {1, 2, ..., L}, L is the number of loudspeakers; m = {1, 2, ..., M}, M is the number of microphones in the i-th control area; h m li(f) is the transfer function from the lth loudspeaker to the mth microphone in the i-th control area; S m li(f) is the acoustic signal S collected by the mth microphone in the i-th control area m where li(t) is the cross power spectral density with the white noise excitation signal wl(t) of the l-th loudspeaker; Sll(f) is the autopower spectral density of the white noise excitation signal wl(t) of the l-th loudspeaker; f is the frequency domain and t is the time domain.

[0039] Step 2: Divide the car's interior sound field into several bright areas and several dark areas according to actual needs, and determine the transfer function H from the speaker array to the microphone array in the bright area based on the measurement results of step 1. B (f) Transfer function H from the loudspeaker array to the microphone array in the dark area D (f) Determine the target sound field P that is expected to be reconstructed in the bright area BT (f) In this embodiment, the navigation sound is played in the driver's seat, which is set as the bright zone; the passenger seat, rear left passenger and rear right passenger areas are kept quiet and set as the dark zone. B (f)=H1(f), P BT (f) is the spectrum characteristics of a certain segment of navigation sound.

[0040] It should be noted that the four different areas can also define different light and dark areas according to actual needs, see Table 1 for details.

[0041] Table 1 Definition of light and dark areas in the car cabin

[0042]

[0043] Step 3: Based on H B (f), H D (f), P BT (f) Constructing a sound field partition control model that considers spatial consistency. In this embodiment, the sound field partition control model that considers spatial consistency is:

[0044] st||P B (f)-P BT (f)|| 2 ≤K1,||q(f)|| 2 ≤K2,||C(f)|| 2 ≤K3;

[0045] Where, P D (f) = H D (f)q(f) is the reconstructed sound field in the dark area, and q(f) is the speaker array excitation signal;

[0046] P B (f) = H B (f)q(f) is the reconstructed sound field in the bright area, K1 is the constraint condition for the reconstruction accuracy of the bright area, and K2 is the constraint condition for the speaker array power;

[0047] C(f)=[H B (f)-h B (f)]q(f) is the spatial consistency parameter of the bright area, h B (f) is the mean value of the transfer function from the loudspeaker array to the microphone array in the bright area, and K3 is the constraint condition for spatial consistency in the bright area;

[0048] The generalized Lagrangian penalty function F(f) corresponding to the sound field partition control model is:

[0049] F(f)=λ1(f)||P D (f)|| 2 +λ2(f)(||P B (f)-P BT (f)|| 2 -K1)+λ3(f)(||q(f)| 2 -K2)+λ4(f)(||C(f)|| 2 -K3),

[0050] Where λ1(f), λ2(f), λ3(f), and λ4(f) are weight factors, all of which are ≥0;

[0051] The loudspeaker array excitation signal q(f) is obtained by solving the equation The optimal solution is obtained.

[0052] In order to test the spatial consistency and partition control performance of the vehicle interior sound field partition control method considering spatial consistency, the method is compared with the ACC method in the prior art, as shown in Table 2 and Figure 5 As shown in Table 2, the time domain level light and dark area sound energy contrast value obtained by the sound field partition control method considering spatial consistency is 22dB, which is not much different from the time domain level light and dark area sound energy contrast value of 23.4dB obtained by the ACC method, indicating that the partition control performance obtained by the two methods is comparable. Figure 5 It can be seen that the maximum difference in sound pressure levels of control points in the bright area of ​​the sound field zoning control method considering spatial consistency is 3.7dB(A), and the maximum difference in sound pressure levels of control points in the bright area of ​​the ACC method is 8.5dB(A), indicating that the sound field zoning control method considering spatial consistency reduces the sound pressure level fluctuations at different positions in the bright area and improves spatial consistency.

[0053] Table 2 Comparison of sound energy in the bright and dark areas of a certain car cabin under different control methods in the time domain

[0054] Control methods Time domain level sound energy contrast value of bright and dark areas dB(A) Sound field zoning control method considering spatial consistency 22 ACC 23.4

[0055] The above embodiments are only preferred embodiments for fully illustrating the present invention, and the protection scope of the present invention is not limited thereto. Any equivalent substitution or modification made by those skilled in the art based on the present invention is within the protection scope of the present invention.

Claims

1. A method for controlling the zoning of the vehicle's interior sound field taking into account spatial consistency, characterized in that: The steps include: Step 1: Measure the transfer function H from the speaker array to the microphone array in different areas of the car. i (f); Step 2: Divide the car's interior sound field into several bright areas and several dark areas according to actual needs, and determine the transfer function H from the speaker array to the microphone array in the bright area based on the measurement results of step 1. B (f) Transfer function H from the loudspeaker array to the microphone array in the dark area D (f) Determine the target sound field P that is expected to be reconstructed in the bright area BT (f); Step 3: Based on H B (f), H D (f), P BT (f) Construct a sound field partition control model considering spatial consistency, determine the generalized Lagrangian penalty function F(f) corresponding to the sound field partition control model, and the speaker array excitation signal q(f) is obtained by solving the equation The optimal solution is obtained; The sound field partition control model considering spatial consistency is: Where, P D (f) = H D (f)q(f) is the reconstructed sound field in the dark area, and q(f) is the speaker array excitation signal; P B (f) = H B (f)q(f) is the reconstructed sound field in the bright area, K1 is the constraint condition for the reconstruction accuracy of the bright area, and K2 is the constraint condition for the speaker array power; C(f)=[H B (f)-h B (f)]q(f) is the spatial consistency parameter of the bright area, h B (f) is the mean value of the transfer function from the loudspeaker array to the microphone array in the bright area, and K3 is the constraint condition for spatial consistency in the bright area; The generalized Lagrangian penalty function F(f) corresponding to the sound field partition control model is: F(f)=λ1(f)||P D (f)|| 2 +λ2(f)(||P B (f)-P BT (f)|| 2 -K1)+λ3(f)(||q(f)|| 2 -K2)+λ4(f)(||C(f)|| 2 -K3), Where λ1(f), λ2(f), λ3(f), and λ4(f) are weight factors, and their values ​​are all ≥0.

2. The method for controlling the vehicle interior sound field partitioning considering spatial consistency according to claim 1, characterized in that: Step 1 is as follows: by giving the speaker array a white noise excitation signal w l (t), the acoustic signals S collected by the microphone array in different areas of the car mli (t) calculated; Where H i (f) is the transfer function matrix from the loudspeaker array to the microphone array in the i-th control area, i = {1, 2, ..., N}, N is the number of control areas; l = {1, 2, ..., L}, L is the number of loudspeakers; m = {1, 2, ..., M}, M is the number of microphones in the i-th control area; h mli (f) is the transfer function from the lth loudspeaker to the mth microphone in the i-th control area; S mli (f) is the acoustic signal S collected by the mth microphone in the i-th control area mli (t) and the white noise excitation signal w of the l-th speaker l The cross power spectral density of (t); S ll (f) is the white noise excitation signal w of the lth speaker l (t); f is the frequency domain and t is the time domain.

3. The method for controlling the vehicle interior sound field zoning according to claim 1, wherein: In step 2, the in-car sound field includes the driver area, the co-pilot area, the rear left passenger area, and the rear right passenger area.

4. A vehicle interior sound field zoning control system that takes spatial consistency into consideration, characterized by: A method for controlling the in-vehicle sound field zoning taking into account spatial consistency as described in any one of claims 1 to 3 can be implemented, comprising a sound field zoning control algorithm integration unit, a digital-to-analog converter, a power amplifier, a speaker array, and a microphone array for collecting in-vehicle sound signals. The sound field zoning control algorithm integration unit calculates a speaker array excitation signal based on the divided bright and dark areas and the target sound field to be reconstructed in the bright area. The speaker array excitation signal is transmitted to the speaker array through the digital-to-analog converter and the power amplifier, and finally the speaker array emits sound.

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