A method and system for active sound control in a vehicle cabin under multiple working conditions based on masking effect

Abstract

The application discloses a kind of based on masking effect's in-vehicle multi-working condition active sound control method and system.The method includes: according to vehicle speed variation, the current driving condition of vehicle is identified;And based on the condition, the duration of active sound in vehicle is dynamically controlled, so that the time characteristics of active sound are continuously adjusted with the change of vehicle condition;While collecting the background noise information in vehicle, based on the amplitude of the adaptive adjustment of active sound of auditory masking effect, so that active sound keeps good perceptibility and auditory comfort under different conditions and different noise levels;During the switching process of condition, the duration and amplitude of active sound are smoothly transitioned to control, to realize the continuous output of active sound.Through the above mode, the application can effectively avoid the sound mutation, masking imbalance or auditory interference problem of existing active sound generation scheme when condition changes, improve the stability and comfort of in-vehicle sound environment under different operating conditions.

Description

Technical Field

[0001] This invention belongs to the field of automotive acoustic control technology, and in particular relates to an active sound control method and system for multiple working conditions in a vehicle based on the masking effect. It can be applied to electric vehicles and other vehicles or transportation tools that use active sound generation methods to regulate the in-vehicle sound environment. Background Technology

[0002] With the rapid development of the new energy vehicle industry, vehicle users are increasingly focusing on higher-level driving comfort and experience quality, shifting their attention from basic indicators such as range and power performance. Among these factors, the in-vehicle acoustic environment, as a crucial element directly impacting the driving experience, has become a key component in evaluating the overall quality of electric vehicles. Unlike traditional gasoline-powered vehicles, electric vehicles eliminate the internal combustion engine and its complex mechanical transmission structure, significantly reducing low-frequency mechanical noise during operation. However, at the same time, the mid-to-high frequency noise generated by the electric drive system, power electronic devices, and the interaction between the tires and the road surface becomes more prominent. This results in an in-vehicle acoustic environment characterized by a dispersed spectral structure, a sharper sound, and insufficient emotional directionality, easily causing auditory fatigue and even discomfort for drivers and passengers.

[0003] To improve the in-vehicle sound quality of electric vehicles, various active sound control or active sound generation solutions have been proposed in related technical fields. These solutions involve the in-vehicle audio system actively outputting specific sounds during driving to compensate for the inherent deficiencies in sound feedback in electric vehicles. Existing active sound technologies typically trigger or modulate preset sound signals based on vehicle operating parameters (such as vehicle speed and acceleration), making them correlated with vehicle operating conditions to some extent, thereby enhancing the driving feedback experience. However, existing solutions still have significant limitations in practical applications, making it difficult to meet the comprehensive requirements for sound quality continuity and comfort under complex driving conditions.

[0004] On the one hand, existing active sound control technologies are relatively limited in their sound type selection. Most solutions still follow the acoustic logic of traditional gasoline vehicles, primarily enhancing the vehicle's dynamic perception by simulating engine sounds. These sounds have strong mechanical properties in terms of spectral structure and auditory characteristics, which do not fully match the operating characteristics of electric vehicles and fail to meet users' demands for personalized and emotional sound experiences. Furthermore, when music or melodic sound sources are introduced, existing technologies typically only perform simple playback or amplitude adjustments, without establishing dedicated control mechanisms for melodic continuity and auditory sensitivity. This can easily create abrupt changes in operating conditions, affecting overall sound quality.

[0005] On the other hand, existing active sound control strategies have limited coverage of vehicle driving conditions, often designed separately for single conditions such as acceleration or constant speed, lacking overall consideration for continuous switching between multiple conditions such as acceleration, constant speed, and deceleration. In actual road driving, the vehicle's operating state changes frequently. If the control strategy cannot smoothly transition with the changes in operating conditions, it can easily lead to discontinuities in the time or intensity characteristics of the active sound, thereby weakening its auxiliary effect and even generating new auditory interference.

[0006] Furthermore, existing technologies generally neglect the dynamic changes in in-vehicle background noise during active sound output. Active sound control often relies on fixed parameters or simple mapping relationships, failing to adequately consider the auditory masking relationship between active sound and background noise. During vehicle operation, background noise fluctuates significantly with factors such as speed and road conditions. When the intensity of active sound is lower than the background noise, its effect is easily masked; conversely, when the intensity of active sound is too high, it may create a new noise burden for passengers, disrupting the overall balance of the in-vehicle acoustic environment. Due to the lack of systematic consideration of masking effects, existing solutions struggle to simultaneously achieve both sound perceptibility and auditory comfort under different operating conditions. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a method and system for active in-vehicle sound control under multiple operating conditions based on the masking effect. Specifically, the technical solution provided by this invention is as follows:

[0008] A method for active in-vehicle sound control under multiple operating conditions based on the masking effect includes the following steps:

[0009] S1. Identify vehicle driving conditions based on changes in vehicle speed, including acceleration, constant speed, and deceleration;

[0010] S2. Determine the duration stretching rate of the sound segment as the active sound inside the vehicle according to the driving conditions. The duration stretching rate is used to shorten the duration of the sound segment as the vehicle speed increases under acceleration conditions, extend the duration as the vehicle speed decreases under deceleration conditions, and maintain the same duration as the previous driving conditions under constant speed conditions.

[0011] S3. Based on the duration stretching rate and vehicle speed update cycle, the original signal of the sound segment is resampled, and the duration of the sound segment is adjusted while maintaining the stability of the original signal spectrum structure to obtain the resampled audio signal.

[0012] S4. Adaptively adjust the output intensity of the resampled audio signal based on the real-time intensity of the background noise inside the vehicle, so as to mask the background noise without creating new noise interference.

[0013] S5. The audio signal with adjusted output intensity is used as the active sound in the vehicle and played through the vehicle speakers.

[0014] Furthermore, in step S1, the vehicle's operating condition is identified by the changes in vehicle speed within the vehicle speed update cycle:

[0015]

[0016] in, Indicates the first k The driving conditions corresponding to each speed update cycle and The first k The starting and ending vehicle speeds of each speed update cycle. This represents the threshold for vehicle speed change used to determine driving conditions.

[0017] Furthermore, the formula for calculating the duration elongation rate in step S2 is as follows:

[0018]

[0019] in, For the first k Real-time vehicle speed within each speed update cycle For the corresponding duration stretching rate, This indicates extending the duration of a sound segment. This indicates shortening the duration of a sound segment; and These are the reference elongation rates for acceleration and deceleration conditions, respectively. and These are the stretching ratio coefficients for acceleration and deceleration conditions, respectively. and These are the reference speeds for acceleration and deceleration conditions, respectively.

[0020] Preferably, in order to avoid abrupt changes in the melody and rhythm of the active sound inside the vehicle when two adjacent vehicle speed update cycles alternate, the duration stretching rate at the beginning of the later vehicle speed update cycle is made equal to the duration stretching rate at the end of the earlier vehicle speed update cycle.

[0021] Furthermore, in step S3, it is assumed that the vehicle speed update cycle is... T v The sampling rate of active sound inside the vehicle is f s The number of sampling points of the resampled audio signal The original signal of the sound segment is resampled using a finite bandwidth resampling algorithm, including the following steps:

[0022] Determine the firstk Resampling time-domain division and interpolation point position within each rate update cycle:

[0023] ,

[0024] in, and The first i The and the first i -1 interpolation point temporal division, For the first k Each speed update cycle ends at the time of the cycle. The elongation rate used For the first k Each speed update cycle begins at the start of the cycle. The elongation rate used and They represent the first N The corresponding time of the first and second sampling points; and The first i The and the first i -1 interpolation point corresponding to the position in the resampled signal sampling sequence;

[0025] The sinc interpolation function is used to reconstruct the resampled audio signal:

[0026]

[0027] ,

[0028] in, This indicates the first sampled audio signal after time stretching. n One sampling point, The first part represents the original signal. m point, For sinc interpolation function, L The half-window length of the sinc interpolation function; and These represent the upper and lower limit indices of the original signal sampling points participating in the interpolation calculation.

[0029] Further, step S4 includes:

[0030] S401. Real-time acquisition of in-vehicle background noise and calculation of its equivalent sound pressure level;

[0031] S402. Determine the real-time target sound pressure level of active sound inside the vehicle based on the auditory masking effect:

[0032]

[0033] in, and They represent the first k The in-vehicle active sound target sound pressure level and background noise equivalent sound pressure level corresponding to each speed update cycle. This is a masking margin used to compensate for the needs of human hearing perception;

[0034] S403. Convert the target sound pressure level into the amplitude gain of the resampled audio signal:

[0035]

[0036] in, For amplitude gain, The original sound pressure level of the audio signal;

[0037] S404. Adjust the audio signal according to the amplitude gain. Perform amplitude scaling:

[0038]

[0039] in, Indicates the first k The amplitude-scaled audio signal corresponding to each speed update cycle.

[0040] Preferably, to prevent the active sound inside the vehicle from being too loud or too weak under extreme conditions, upper and lower limits are imposed on the target sound pressure level:

[0041]

[0042] in, To determine the target sound pressure level after applying constraints, and These represent the minimum and maximum permissible sound pressure levels for active sound, respectively.

[0043] Furthermore, when the vehicle's driving conditions change, to avoid discontinuous changes in amplitude and perceived sound of the in-vehicle active sound corresponding to different conditions, crossfade-in and crossfade-out processing is performed within the switching window:

[0044] Let the length of the switching window be... T c The corresponding number of sampling points is N c Then in the switching window, the first i The output signal of each sampling point is represented as:

[0045]

[0046] in, and These represent the active in-vehicle sound levels before and after the operating condition switch. i Each sampling point signal; and Let represent the fade-out and fade-in weights respectively, and satisfy . The weighting function uses a smoothing function to ensure the continuity of sound energy during the switching process.

[0047] An in-vehicle multi-condition active sound control system based on the above method, the system includes the following modules:

[0048] The operation status perception module is used to acquire at least one operation parameter that reflects the vehicle's operating status;

[0049] The driving condition determination module is used to identify the current driving condition of the vehicle based on the operating parameters.

[0050] The active sound time characteristic adjustment module is used to adjust the duration of the sound signal, which is the active sound source in the vehicle, according to the driving conditions, so that the time characteristics of the active sound change accordingly with the vehicle's driving conditions.

[0051] The background noise sensing module is used to collect in-vehicle background noise signals and calculate the in-vehicle background noise intensity.

[0052] An active sound amplitude adaptive control module is used to determine the target output intensity of the active sound inside the vehicle based on the background noise intensity inside the vehicle, and to adjust the amplitude of the sound signal that serves as the active sound source inside the vehicle, so that the active sound can mask the background noise and not produce auditory interference.

[0053] The sound continuity control module is used to perform continuity constraints or smooth transition processing on the time characteristics and amplitude characteristics of the active sound signal when switching driving conditions or updating active sound control parameters.

[0054] The active sound output module is used to output active sound signals, which have undergone time characteristic adjustment, amplitude control and continuous processing, to the vehicle through the speaker system.

[0055] A computer-readable storage medium storing a computer program, which, when executed by a processor, performs the steps of the in-vehicle multi-condition active voice control method as described above.

[0056] Compared to existing in-vehicle active sound control technologies, this invention achieves significant advantages in terms of sound environment adaptability, control continuity, and auditory comfort. By incorporating multiple driving conditions into a unified control framework, the active sound can change smoothly and continuously with different operating states such as acceleration, constant speed, and deceleration. This avoids the abrupt changes or disjointed sound caused by condition switching in existing technologies, thereby improving the overall consistency and naturalness of the in-vehicle sound experience. Simultaneously, this invention incorporates comprehensive consideration of the changing characteristics of in-vehicle background noise during active sound control, ensuring that the active sound output maintains good auditory harmony with the background noise. This effectively prevents the active sound from being masked by background noise or excessively outputting, thus avoiding new noise interference and significantly improving the stability of sound quality under different vehicle speeds and road conditions.

[0057] Furthermore, this invention, through the coordinated regulation of the temporal and intensity characteristics of active sound, enables in-vehicle sound to not only reflect changes in vehicle operating status but also maintain a good balance between perceptibility and comfort at the auditory level. This enhances the driver's and passengers' intuitive perception of vehicle dynamics while reducing the risk of auditory fatigue during long-distance driving. Compared to existing active sound generation solutions that mainly rely on fixed mapping relationships or single parameter adjustments, this invention exhibits stronger environmental adaptability and control precision in complex driving scenarios, better meeting the actual needs of electric vehicles for a high-quality, intelligent in-vehicle sound environment. Therefore, it has significant advantages in both overall acoustic experience and practical application. Attached Figure Description

[0058] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0059] Figure 1 This is a schematic diagram of the in-vehicle multi-condition active sound control framework provided in an embodiment of the present invention;

[0060] Figure 2 This is a time-frequency analysis diagram of the active sound signal collected under combined driving conditions provided in an embodiment of the present invention;

[0061] Figure 3 This is the sound pressure level-time curve of in-vehicle background noise, target sound, and actual active sound under combined driving conditions provided in this embodiment of the invention;

[0062] Figure 4 This is a schematic diagram of the in-vehicle multi-condition active sound control system module provided in an embodiment of the present invention. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative effort are all within the scope of protection of the present invention.

[0064] Example 1

[0065] like Figure 1 As shown, this embodiment provides an in-vehicle multi-condition active sound control method based on the masking effect.

[0066] In this embodiment, a musical clip is used as the active sound source for the in-vehicle audio. Compared to the simulated engine sound, which uses changes in amplitude and frequency to convey acceleration and deceleration, the acceleration and deceleration sensation based on the active sound of a musical clip mainly depends on changes in duration and amplitude. Furthermore, while adjusting the duration, it is also necessary to ensure the audibility of the musical clip's melody. The main reason for using a musical clip as the active sound source in this embodiment is that musical clips have harmonious melodies and diverse styles, naturally suited to comfort and personalized expression needs, making the solution more valuable for practical application. Moreover, because musical clips possess melodic characteristics, they are more sensitive to subtle deviations in control parameters, making control more difficult. Solving these control challenges can lead to a wider range of applications and stronger technological barriers.

[0067] It should be noted that the solution of this invention is universal. If the music clip is replaced with a simulated engine sound or other sound clips, only the basic parameters of the sound source need to be adjusted, and the control framework of this invention is fully applicable. Furthermore, this invention does not specifically describe or limit the design or selection of music clips as active sound sources within the vehicle. Those skilled in the art or users can fully personalize the active sound sources for various driving conditions according to their own preferences (e.g., using sound clip 1 during acceleration, sound clip 2 during constant speed driving, and sound clip 3 during deceleration), or use a matching algorithm to select appropriate sound clips from the sound source library in real time. The core of this invention lies in the control of the parameters (duration and amplitude) of the active sound within the vehicle.

[0068] In this embodiment, the driving condition is identified by calculating the rate of change of vehicle speed and comparing it with a preset threshold:

[0069]

[0070] in, Indicates the first k Each speed update cycle corresponds to the driving conditions, including acceleration, deceleration, and constant speed. and They represent the first k The starting speed and ending speed in each speed update cycle This represents the threshold for vehicle speed change used to determine driving conditions.

[0071] To dynamically control the active sound within the vehicle according to different driving conditions, targeted control strategies are adopted based on the characteristics of each driving condition. For acceleration, a duration stretching strategy is used to enhance the perception of acceleration. As vehicle speed increases, the duration of the active sound music segments gradually shortens, resulting in a faster music rhythm to convey a sense of acceleration. For deceleration, as vehicle speed decreases, the duration of the music segments gradually lengthens, resulting in a slower music rhythm to convey a sense of deceleration. Simultaneously, amplitude control of the music segments is also necessary for both acceleration and deceleration. If the active sound cannot mask the background noise, it will be drowned out; conversely, if the active sound excessively masks the background noise, it will create new auditory interference. Therefore, the main purpose of amplitude control is to maintain the active sound at the amplitude required to mask the background noise, ensuring harmony between the active sound and the background noise. For constant speed driving, to avoid sudden changes in sound duration and amplitude when transitioning from acceleration or deceleration to constant speed, the active sound in constant speed driving needs to follow the duration stretching and amplitude control parameters of the previous condition.

[0072] 1. Active sound duration stretching and resampling

[0073] To address duration stretching control, a mapping relationship is established between the duration stretching rate of music segments and vehicle speed, enabling quantitative control of the degree of duration stretching. This embodiment uses a linear variation model to characterize this relationship. The specific formulas for the duration stretching rate under acceleration, deceleration, and constant speed conditions are as follows:

[0074]

[0075] in, For the first k Real-time vehicle speed within each speed update cycle This is the corresponding duration stretching rate, with values ​​greater than 1 and less than 1 indicating extended and shortened durations, respectively. and These represent the reference elongation rates for acceleration and deceleration conditions, respectively. In this embodiment, they are set to... ; and These represent the stretching ratio coefficients for acceleration and deceleration conditions, respectively. In this embodiment, they are set to... and ; and These are the reference speeds for acceleration and deceleration conditions, which are set to [specific values] in this embodiment. and .

[0076] Since the vehicle speed signal is a discrete signal that is continuously updated at a fixed sampling interval, the duration stretching ratio of the active sound should correspond to each discrete vehicle speed value. Furthermore, the duration of the active sound should be consistent with the discrete vehicle speed update period. Assuming the vehicle speed update period is... T v The sampling rate of active sound f s The active sound after the duration is stretched has N If there are discrete sampling points, then we have .

[0077] To ensure the duration of the elongation rate from the first k The speed update cycle to the [number]th ... k +1 speed update cycle will not change suddenly, and it needs to be guaranteed , Indicates the first k The duration stretching rate used at the end of each cycle (corresponding to the last sampling point in that cycle). Then it means the first k +1 is the duration stretching rate used at the beginning of the cycle (corresponding to the initial sampling point within the cycle). That is, at the boundary between two adjacent vehicle speed update cycles, the duration stretching rate of the active sound must be continuous and cannot jump. Otherwise, the sound will suddenly become faster or slower, the melody rhythm will be broken, and there will be obvious abrupt changes in the listening experience, which is unacceptable in music clips or continuous sound effects.

[0078] In determining the first k After the duration stretching rate within each vehicle speed update cycle, the corresponding active audio signal needs to undergo duration stretching processing to match the temporal characteristics of the active sound with the vehicle's driving conditions. This embodiment uses a finite bandwidth resampling algorithm to achieve duration stretching of the audio signal. This algorithm can change the audio duration while ensuring the basic stability of the spectral structure within the audible frequency band, avoiding the obvious distortion problems caused by simple extraction or repeated sampling points.

[0079] Suppose the original active sound audio signal is a discrete time series. x ( m ),in m This represents the sampling point number of the original audio. To achieve duration stretching, a new set of sampling point positions needs to be reconstructed on the original audio signal, and the output audio signal is generated accordingly. According to the resampling principle, the duration stretching ratio of the resampled signal relative to the original signal is inversely proportional to the time-domain division of the resampled signal interpolation points. Therefore, in the... k Within the first speed update cycle, the first iThe temporal resolution of each interpolation point can be calculated as follows:

[0080]

[0081] Furthermore, the first i The position of each interpolation point can be represented as follows:

[0082]

[0083] Once the locations of these interpolation points are determined, the finite bandwidth resampling algorithm uses the sinc interpolation function to reconstruct the resampled signal. This ensures the sound quality after duration stretching.

[0084] The specific interpolation method is as follows:

[0085]

[0086] ,

[0087] in, This indicates the resampled output signal after duration stretching. The first part represents the original signal. m point, This represents the sinc interpolation function. L This is the half-window length of the sinc interpolation function.

[0088] 2. Amplitude control based on masking effect

[0089] After the duration stretching of the active sound is completed, the active sound amplitude control stage based on the masking effect begins. The core purpose of this stage is to dynamically determine the output intensity of the active sound according to the real-time changes in the in-vehicle background noise, so that the active sound can be clearly perceived by the driver and passengers, but will not create new noise interference due to excessive output, thereby achieving auditory coordination between the active sound and the in-vehicle background noise.

[0090] Within each vehicle speed update cycle, the in-vehicle background noise signal is first acquired. This background noise signal can be acquired by a single microphone or an array of microphones positioned inside the vehicle, with the sound sampling frequency matching or being an integer division of the active sound processing sampling frequency. Within this cycle, the equivalent sound pressure level of the acquired background noise signal is calculated to characterize the current in-vehicle background noise intensity.

[0091] The effective sound pressure level of background noise can be calculated as follows:

[0092]

[0093] in, Indicates the first k The sound pressure level of the in-vehicle background noise within each speed update cycle, in decibels (dB). For reference sound pressure, 20 μPa is usually taken.

[0094] Indicates the first k The root mean square sound pressure level of the background noise signal within each speed update cycle, i.e.:

[0095]

[0096] in, For the first time in this period n The instantaneous sound pressure corresponding to each sound sampling point N This represents the number of sampling points within that period. The root mean square sound pressure level reflects the equivalent energy level of the background noise within that period.

[0097] After obtaining the background noise sound pressure level, the target output sound pressure level of the active sound within that period is determined based on the principle of auditory masking. The auditory masking effect indicates that when two sounds coexist, the stronger sound masks the weaker sound, making the latter difficult for the human ear to perceive. Therefore, to ensure the perceptibility of the active sound, its sound pressure level should be at least a certain margin higher than the background noise, but this margin should not be too large to avoid introducing new auditory burden.

[0098] In this embodiment, the target sound pressure level of the active sound is modeled as a time-varying function that varies with background noise:

[0099]

[0100] in, Indicates the first k The active acoustic target sound pressure level corresponding to each speed update cycle; To provide a masking margin to compensate for the human ear's perception of active sound, it is usually set to 0~6dB.

[0101] To prevent the active sound from being too loud or too weak in extreme cases, upper and lower limits are further imposed on the target sound pressure level to obtain the final target sound pressure level:

[0102]

[0103] in, That is, the target sound pressure level after constraints are applied; This indicates the minimum permissible sound pressure level for active sound, used to prevent the active sound output from being too low and thus failing. This indicates the maximum permissible sound pressure level of active sound, used to ensure driving safety and auditory comfort.

[0104] Subsequently, the target sound pressure level is converted into the amplitude gain of the current active sound signal. Let the active sound signal after time stretching be... In its first k The effective sound pressure level (the original sound pressure level of the music segment as active sound) within each speed update cycle is: The corresponding linear magnitude gain It can be represented as:

[0105]

[0106] After obtaining the amplitude gain, for the first k The amplitude of the active acoustic signal within each speed update cycle is scaled to obtain the final output signal: , This refers to the active sound signal that is ultimately output to the car speakers. n This indicates the audio sampling point number.

[0107] When the vehicle's driving conditions change (e.g., from acceleration to constant speed, or from constant speed to deceleration), crossfade-in and crossfade-out processing is performed within the switching time window to avoid discontinuous changes in amplitude and auditory perception of the active sounds corresponding to different driving conditions. Let the switching window length be... T c The corresponding number of sampling points is N c Then in the switching window, the first i The output signal at each sampling point can be expressed as:

[0108]

[0109] in, and These represent the active sound before and after the operating condition switch. i Each sampling point signal, and Let represent the fade-out and fade-in weights respectively, and satisfy . The weighting function can be a linear function, a cosine function, or other smooth functions to ensure the continuity of sound energy during the switching process.

[0110] To verify the effectiveness of the method under different driving conditions, a combined driving condition was designed, integrating acceleration, constant speed, and deceleration. Specifically, the car accelerates from 40 km / h to 80 km / h, maintains a constant speed of 80 km / h, and then decelerates back to 40 km / h. Each driving condition lasts for 20 seconds. A customized active sound control test platform for this combined driving condition was established within a closed automotive cabin test bench: a laptop computer outputs signals simulating the car's driving conditions, which are transmitted to a controller via a junction box. The controller then controls a power amplifier, which drives an active speaker to emit the target active sound. Recorded background noise from an electric vehicle emitted by the speaker is reproduced to accurately simulate the actual working environment of the active sound system. Furthermore, the sound signals are acquired using a data acquisition device and a human head. To ensure consistency between the test and the actual in-vehicle environment, the positions of the active sound speaker and the seats in the test bench are consistent with those in the actual vehicle.

[0111] like Figure 2 As shown, time-frequency analysis was performed on the acquired active sound signal to verify the effectiveness of the duration stretching control strategy. The time-frequency diagram is divided into three parts: acceleration phase (0-20s), constant speed phase (20-40s), and deceleration phase (40-60s). These three phases are divided by white vertical dashed lines. During the acceleration phase, as the vehicle speed increases, the fundamental frequency and harmonic frequency components of the music clip gradually increase, such as... Figure 2 The red dashed line indicates this. Substituting the initial and final vehicle speeds during acceleration into the duration stretching formula, the initial and final duration stretching rates of the active sound are determined to be 1 and 0.5, respectively, indicating that the final duration stretching rate is 0.5 times the initial value. Since the duration stretching ratio is inversely proportional to the frequency change rate, theoretically, the final frequency should be twice the initial frequency. Using the white dashed auxiliary line, the initial and final frequency ratio is determined to be 2.08, corresponding to a relative error of 4.0%. Similarly, the initial and final scaling factors of other fundamental and harmonic frequency components also approximately double, further confirming the effectiveness of this control method under acceleration conditions. During deceleration, as the vehicle speed decreases, the fundamental and harmonic components of the music segment gradually decrease. Using the same calculation method, the final frequency is found to be 0.6 times the initial frequency. The initial and final scaling factors of other harmonic components are also approximately 0.6 times, verifying the effectiveness of this control method under deceleration conditions. Meanwhile, during constant speed conditions, the fundamental and harmonic frequency components of the music segment remain stable, consistent with the final and initial frequencies of acceleration and deceleration conditions, respectively. These results collectively validate the effectiveness of the duration stretching control strategy under multiple driving conditions.

[0112] like Figure 3As shown, the sound pressure level-time curves of the original background noise, the target active sound, and the measured active sound under combined driving conditions are displayed. It can be observed that the dynamic change trends of the sound pressure levels of the actual active sound and the background noise are consistent, demonstrating a good masking coordination relationship between the two. Furthermore, under this combined driving condition, the total root mean square error (RMSE) of the sound pressure level tracking the target sound is 0.09 dB, with a relative error of 1.3%, verifying the effectiveness of the amplitude control method of this invention.

[0113] A subjective panel evaluation method was employed to assess sound quality in three scenarios: original background noise from a car, the combined sound of active engine noise and background noise, and the combined sound of active engine noise and background noise based on a music clip. The distribution of the subjective evaluation panel members is shown in Table 1. The subjective evaluation used a rating scale, with 11 levels from 0 to 10. The corresponding evaluation terms are shown in Table 2.

[0114] Table 1 Composition of the Subjective Jury

[0115]

[0116] Table 2 Rating Scale

[0117]

[0118] As shown in Table 3, the sound quality score of the active sound based on the music clip is 8.0, while the sound quality score of the background noise is 5.1, which is an improvement of 57%, further verifying the effectiveness of the method of the present invention.

[0119] Table 3 Subjective rating table for original vehicle background noise, internal combustion engine blending noise, and blending noise based on music clips.

[0120]

[0121] Example 2

[0122] Based on the above method, this embodiment provides an in-vehicle multi-condition active sound control system for adaptively adjusting the active sound inside the vehicle during driving, so as to achieve a continuous and comfortable sound output effect that matches the vehicle's operating status and in-vehicle acoustic environment. The system is integrated into the vehicle's electronic and electrical architecture and can be deployed as an independent acoustic control unit, or it can work in conjunction with existing in-vehicle infotainment systems or body control systems.

[0123] like Figure 4As shown, the system generally includes an operating status perception module, a driving condition determination module, an active sound time characteristic adjustment module, a background noise perception module, an active sound amplitude adaptive control module, a sound continuity processing module, and an active sound output module. All modules work together under a unified control logic to jointly complete the adjustment and control of the active sound inside the vehicle.

[0124] The operational status perception module is used to acquire basic information reflecting the current operational status of the vehicle. Its input signals can come from existing sensors or control units in the vehicle, including but not limited to vehicle speed signals, acceleration signals, motor speed signals, or combinations thereof. This module collects and preprocesses the above operational parameters and provides stable and reliable operational status data to subsequent modules according to a preset update cycle, providing a data foundation for subsequent operating condition identification.

[0125] The driving condition determination module is connected to the operation status perception module and is used to identify the vehicle's current driving condition based on the acquired operation status parameters. This module analyzes the changes in operation parameters within adjacent update cycles to determine whether the vehicle is in different conditions such as acceleration, deceleration, or constant speed, and outputs the determination result as a control signal to the subsequent active sound control module. Through this module's configuration, the system can automatically switch the corresponding sound control strategy under various driving conditions without manual intervention.

[0126] The active sound timing characteristic adjustment module adjusts the timing characteristics of the active sound signal based on the operating condition information output by the driving condition determination module. This module incorporates sound timing adjustment logic to determine adjustment parameters for the duration, rhythm, or playback speed of the active sound, and performs duration stretching or compression processing on the original active sound signal based on these parameters. By adjusting the sound timing characteristics, the active sound is made audibly correspond to the dynamic changes of the vehicle's acceleration, deceleration, or constant speed, thereby enhancing the auditory representation of the vehicle's operating state.

[0127] The background noise sensing module is used to collect in-vehicle background noise information. It acquires ambient sound signals through one or more microphones placed inside the vehicle, analyzes the collected background noise, and extracts characteristic parameters that characterize the background noise intensity. The output of this module reflects the current changes in the in-vehicle acoustic environment, providing real-time data for active sound amplitude control.

[0128] The active sound amplitude adaptive control module is connected to the background noise perception module and the active sound time characteristic adjustment module. It determines the target output intensity of the active sound based on background noise information and the characteristics of the active sound signal. Based on the principle of auditory masking, this module ensures that the active sound is effectively perceived within the background noise without causing additional auditory burden to the driver and passengers due to excessive output. It also applies corresponding amplitude adjustment to the active sound signal to achieve harmony between the active sound and the in-vehicle background noise.

[0129] The sound continuity processing module performs continuity constraint processing on the active sound signal when the vehicle's driving conditions change or the active sound control parameters are updated. This module smoothly controls the transition of active sound signals at different times or under different conditions, avoiding discontinuous changes in the time or intensity characteristics of the sound due to sudden parameter changes, thereby improving the naturalness and comfort of the in-vehicle sound experience.

[0130] The active sound output module outputs the active sound signal, after time characteristic adjustment, amplitude control, and continuous processing, to the vehicle speaker system to achieve actual playback of active sound inside the vehicle. This module can share hardware resources with the vehicle's existing audio system or be set up as an independent sound output channel, thus ensuring good engineering compatibility and application flexibility of the system.

[0131] In terms of the overall workflow, the system first obtains vehicle operating parameters in real time through the operating status perception module, and then identifies the current driving condition through the driving condition determination module. Subsequently, the active sound time characteristic adjustment module adjusts the time characteristics of the active sound signal according to the operating condition information, while the background noise perception module collects and analyzes the background noise inside the vehicle. Based on the above information, the active sound amplitude adaptive control module determines the output intensity of the active sound and completes the amplitude adjustment. The continuous processing module smooths the changes in sound parameters when necessary. Finally, the active sound output module plays the processed active sound into the vehicle, thus forming an in-vehicle active sound control process that adaptively adjusts to changes in vehicle operating conditions and acoustic environment.

[0132] The above system can execute the in-vehicle multi-condition active sound control method described in Embodiment 1, and has the corresponding functional modules and beneficial effects of the method. For technical details not described in detail in this embodiment, please refer to the in-vehicle multi-condition active sound control method provided in Embodiment 1 of the present invention.

[0133] Through the above description of the embodiments, those skilled in the art can clearly understand that each embodiment can be implemented using software plus a general-purpose hardware platform, or of course, using hardware. Based on this understanding, the above technical solutions, in essence or the parts that contribute to the related technology, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute the methods described in the various embodiments or some parts of the embodiments.

[0134] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; under the concept of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the present invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for active in-vehicle sound control under multiple operating conditions based on the masking effect, characterized in that, Including the following steps: S1. Identify vehicle driving conditions based on changes in vehicle speed, including acceleration, constant speed, and deceleration; S2. Determine the duration stretching rate of the sound segment as the active sound inside the vehicle according to the driving conditions. The duration stretching rate is used to shorten the duration of the sound segment as the vehicle speed increases under acceleration conditions, extend the duration as the vehicle speed decreases under deceleration conditions, and maintain the same duration as the previous driving conditions under constant speed conditions. S3. Based on the duration stretching rate and vehicle speed update cycle, the original signal of the sound segment is resampled, and the duration of the sound segment is adjusted while maintaining the stability of the original signal spectrum structure to obtain the resampled audio signal. S4. Adaptively adjust the output intensity of the resampled audio signal based on the real-time intensity of the background noise inside the vehicle, so as to mask the background noise without creating new noise interference. S5. The audio signal with adjusted output intensity is used as the active sound in the vehicle and played through the vehicle speakers.

2. The in-vehicle multi-condition active sound control method as described in claim 1, characterized in that, In step S1, the vehicle's operating condition is identified by the changes in vehicle speed within the vehicle speed update cycle: in, Indicates the first k The driving conditions corresponding to each speed update cycle and The first k The starting and ending vehicle speeds of each speed update cycle. This represents the threshold for vehicle speed change used to determine driving conditions.

3. The in-vehicle multi-condition active sound control method as described in claim 1, characterized in that, The formula for calculating the elongation rate under acceleration, deceleration, and constant speed conditions in step S2 is as follows: in, For the first k Real-time vehicle speed within each speed update cycle For the corresponding duration stretching rate, This indicates extending the duration of a sound segment. This indicates shortening the duration of a sound segment; For the first k -1 time stretching rate within a speed update cycle; and These are the reference elongation rates for acceleration and deceleration conditions, respectively. and These are the stretching ratio coefficients for acceleration and deceleration conditions, respectively. and These are the reference speeds for acceleration and deceleration conditions, respectively.

4. The in-vehicle multi-condition active sound control method as described in claim 3, characterized in that, To avoid abrupt changes in the melody and rhythm of the in-vehicle active sound when two adjacent vehicle speed update cycles alternate, the duration stretching rate at the start of the later vehicle speed update cycle is made equal to the duration stretching rate at the end of the earlier vehicle speed update cycle.

5. The in-vehicle multi-condition active sound control method as described in claim 3, characterized in that, In step S3, it is assumed that the vehicle speed update cycle is T v The sampling rate of active sound inside the vehicle is f s The number of sampling points of the resampled audio signal ; The original signal of the sound segment is resampled using a finite bandwidth resampling algorithm, including the following steps: Determine the first k Resampling time-domain division and interpolation point position within each rate update cycle: ， in, and The first i The and the first i -1 interpolation point temporal division, For the first k Each speed update cycle ends at the time of the cycle. The elongation rate used For the first k Each speed update cycle begins at the start of the cycle. The elongation rate used and They represent the first N The corresponding time of the first and second sampling points; and The first i The and the first i -1 interpolation points correspond to the positions in the original signal sampling sequence; The sinc interpolation function is used to reconstruct the resampled audio signal: ， in, This indicates the first sampled audio signal after time stretching. n One sampling point, The first part represents the original signal. m point, For sinc interpolation function, L The half-window length of the sinc interpolation function; and These represent the upper and lower limit indices of the original signal sampling points participating in the interpolation calculation.

6. The in-vehicle multi-condition active sound control method as described in claim 1, characterized in that, Step S4 includes: S401. Real-time acquisition of in-vehicle background noise and calculation of its equivalent sound pressure level; S402. Determine the real-time target sound pressure level of active sound inside the vehicle based on the auditory masking effect: in, and They represent the first k The in-vehicle active sound target sound pressure level and background noise equivalent sound pressure level corresponding to each speed update cycle. This is a masking margin used to compensate for the needs of human hearing perception; S403. Convert the target sound pressure level into the amplitude gain of the resampled audio signal: in, For amplitude gain, The original sound pressure level of the audio signal; S404. Adjust the audio signal according to the amplitude gain. Perform amplitude scaling: in, Indicates the first k The amplitude-scaled audio signal corresponding to each speed update cycle.

7. The in-vehicle multi-condition active sound control method as described in claim 6, characterized in that, To prevent the active sound inside the vehicle from being too loud or too weak under extreme conditions, upper and lower limits are imposed on the target sound pressure level: in, To determine the target sound pressure level after applying constraints, and These represent the minimum and maximum permissible sound pressure levels for active sound, respectively.

8. The in-vehicle multi-condition active sound control method as described in claim 1, characterized in that, When the vehicle's driving conditions change, to avoid discontinuous changes in amplitude and perceived sound of the in-vehicle active sound corresponding to different conditions, cross-fade-in and cross-fade-out processing is performed within the switching time window: Let the length of the switching window be... T c The corresponding number of sampling points is N c Then in the switching window, the first i The output signal of each sampling point is represented as: in, and These represent the active in-vehicle sound levels before and after the operating condition switch. i Each sampling point signal; and Let represent the fade-out and fade-in weights respectively, and satisfy . The weighting function uses a smoothing function to ensure the continuity of sound energy during the switching process.

9. An in-vehicle multi-condition active sound control system based on the method of any one of claims 1 to 8, characterized in that, Includes the following modules: The operation status perception module is used to acquire at least one operation parameter that reflects the vehicle's operating status; The driving condition determination module is used to identify the current driving condition of the vehicle based on the operating parameters. The active sound time characteristic adjustment module is used to adjust the duration of the sound signal, which is the active sound source in the vehicle, according to the driving conditions, so that the time characteristics of the active sound change accordingly with the vehicle's driving conditions. The background noise sensing module is used to collect in-vehicle background noise signals and calculate the in-vehicle background noise intensity. An active sound amplitude adaptive control module is used to determine the target output intensity of the active sound inside the vehicle based on the background noise intensity inside the vehicle, and to adjust the amplitude of the sound signal that serves as the active sound source inside the vehicle, so that the active sound can mask the background noise and not produce auditory interference. The sound continuity control module is used to perform continuity constraints or smooth transition processing on the time characteristics and amplitude characteristics of the active sound signal when switching driving conditions or updating active sound control parameters. The active sound output module is used to output active sound signals, which have undergone time characteristic adjustment, amplitude control and continuous processing, to the vehicle through the speaker system.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, which, when executed by a processor, performs the steps of the in-vehicle multi-condition active voice control method as described in any one of claims 1 to 8.

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