An audio enhancement system and method for a downhole broadcast system

Abstract

The application discloses an audio enhancement system and method of a downhole broadcasting system, relates to the technical field of audio enhancement, and obtains a noise signal and an original audio signal in a mine roadway, carries out standardization processing, encoding transmission and decoding on the noise signal to obtain a standardized noise signal, performs phase inversion operation on the standardized noise signal after frequency-division amplitude shaping and time delay compensation, generates a reverse noise signal, predicts a reverberation component in the roadway based on the original audio signal and a roadway sound reflection model, generates a reverse reverberation signal after phase inversion, introduces a reverberation gate control coefficient to perform weighted control, and obtains an actual reverse reverberation signal, and superimposes the original audio signal, the reverse noise signal and the actual reverse reverberation signal to obtain a final audio signal. The application utilizes the principle of destructive interference and can effectively reduce the influence of environmental noise and reverberation.

Description

Technical Field

[0001] This invention relates to the field of audio enhancement technology, and in particular to an audio enhancement system and method for an underground broadcasting system. Background Technology

[0002] The statements in this section are merely background information relating to this disclosure and do not necessarily constitute prior art.

[0003] In coal mine operations, due to the harsh underground conditions, complex roadway structures, dispersed work sites, and high personnel mobility, mine broadcasting is one of the key means of information transmission and safety management. Under normal circumstances, mine broadcasting is mainly used for safety announcements, dispatching and command, and public voice notifications, enabling synchronized work organization, instruction issuance, and information dissemination. In the event of an emergency underground, mine broadcasting can be centrally dispatched by the dispatching and command center to issue emergency instructions and evacuation guidance information in a fixed-point, zoned, or global manner, organizing underground personnel to quickly and orderly evacuate to designated safe locations to minimize the impact of accidents and losses to personnel and property. However, traditional mine voice alarms have the following drawbacks: Traditional underground broadcasting systems are prone to sound distortion or blurring due to noise interference from the underground environment (such as mechanical operation, airflow, mining operations, etc.), and the volume and voice content are easily masked and suppressed by strong environmental noise, making it difficult for personnel to clearly receive broadcast information; underground structures are complex, typically containing narrow passages and open spaces, making it difficult for traditional broadcasting systems to evenly cover the entire underground area, often resulting in problems of "too loud" or "too weak" sound; broadcast sound mainly propagates in all directions, leading to numerous sound reflections and significant interference, reducing the efficiency of actual information transmission; existing broadcasting systems fail to dynamically adjust audio signals according to real-time environmental changes (such as noise levels and personnel distribution), making it difficult to meet the information transmission needs in complex and dynamic environments.

[0004] Existing technologies, such as signal noise reduction methods, devices, and electronic equipment, have solved the problem of suppressing environmental noise. This is mainly achieved by using algorithms to identify and classify noise (environmental noise and channel noise), and then eliminating or repairing distortion accordingly. For example, a sound effect recommendation method, system, and device based on sound reverberation suppression and white noise primarily addresses the decline in auditory comfort caused by engine / tire / wind noise and in-vehicle reverberation within the vehicle cabin, as well as the lack of comprehensive perception and dynamic adaptation of existing sound effect recommendation systems to the "current in-vehicle sound environment + user preferences." The approach involves preprocessing and performing spectral analysis on real-time in-vehicle sound to determine the noise source / type and extract features. Simultaneously, a "white noise sound effect preference model" is established through interactive data. Then, matching white noise sound effects are selected from a sound effect library and mixed with the original in-vehicle audio, with the mixing ratio dynamically adjusted before playback. This improves the experience through a combination of "white noise shielding + recommended matching."

[0005] Due to the complex structure of underground mine roadways, the variable sound propagation paths, and strong reflections, coupled with strong noise from mechanical operation, mining activities, and airflow, the noise is characterized by prominent low-frequency components, non-stationarity, and random spatial distribution. This makes existing audio noise reduction / enhancement technologies difficult to apply in engineering settings within mine environments. Traditional methods often use global filters to process the entire signal uniformly, which easily produces distortion and edge effects, and is difficult to effectively eliminate random time-varying noise. Some methods only focus on time-domain / frequency-domain characteristics, ignoring time-frequency correlations and spatial propagation differences, resulting in effects that are significantly affected by noise time-varying and frequency bands. At the same time, underground broadcasts suffer from severe reverberation and a high proportion of reflected sound, making it difficult for traditional techniques to separate and suppress reflected components, resulting in muffled, trailing speech and reduced intelligibility. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention provides an audio enhancement system and method for an underground broadcasting system. By generating reverse noise signals and reverse reverberation signals in real time and utilizing the principle of destructive interference, the influence of environmental noise and reverberation can be effectively reduced.

[0007] To achieve the above objectives, one or more embodiments of the present invention provide the following technical solutions:

[0008] In a first aspect, the present invention provides an audio enhancement system for a downhole broadcasting system, comprising:

[0009] A signal acquisition unit is used to acquire audio data in a mine roadway; the audio data includes noise signals and raw audio signals.

[0010] The first signal processing unit is used to standardize the noise signal to obtain a standardized noise signal, which is then encoded to obtain a coded noise signal.

[0011] The second signal processing unit is used to decode the coded noise signal and generate energy balance coefficient and time delay compensation parameter based on the noise signal and target control area parameters. The standardized noise signal and the original audio signal are transmitted to the third signal processing unit and the fourth signal processing unit, respectively.

[0012] The third signal processing unit is used to perform frequency band amplitude shaping and time delay compensation on the standardized noise signal, and then perform a phase reversal operation to generate an inverse noise signal.

[0013] The fourth signal processing unit is used to predict the reverberation component in the tunnel based on the original audio signal and the tunnel sound reflection model, generate the reverse reverberation signal after phase inversion, and introduce reverberation gating coefficients for weighted control to obtain the actual reverse reverberation signal.

[0014] The fifth signal processing unit is used to superimpose the original audio signal, the inverse noise signal, and the actual inverse reverberation signal to obtain the final audio signal.

[0015] In a further technical solution, the second signal processing unit performs a comprehensive analysis of the timestamp, energy distribution, and spatial correlation characteristics of the noise signal based on the decoded noise signal, and generates an energy balance coefficient and a time delay compensation parameter.

[0016] A further technical solution is that the frequency band amplitude shaping specifically involves: dividing the standardized noise signal into multiple frequency components, applying amplitude shaping weights to each frequency component based on the energy balance coefficient, and obtaining the noise signal after frequency band amplitude shaping.

[0017] A further technical solution involves introducing time delay compensation into the noise signal after frequency band amplitude shaping to obtain a time delay compensated noise signal.

[0018] A further technical solution is that the tunnel acoustic reflection model is represented as follows:

[0019]

[0020] in, For reverberation signal, The original audio signal. For the first Attenuation coefficient of each reflection path, For the signal at the specified acquisition point, For the first The propagation delay of each reflection path, The number of reflection paths, is the time constant.

[0021] In a further technical solution, the attenuation coefficient is expressed as:

[0022]

[0023] in, The attenuation coefficient is... For the first The intensity of the reflected signal, The intensity of the initial reflected signal;

[0024] The propagation delay is expressed as:

[0025]

[0026] in, To delay the transmission time, For the first The propagation distance of a reflection path, c This is the speed at which sound travels through the air.

[0027] A further technical solution involves limiting the amplitude of the superimposed signals to obtain the final audio signal.

[0028] Secondly, the present invention provides an audio enhancement method for a downhole broadcasting system, comprising:

[0029] Acquire audio data from within a mine roadway; the audio data includes noise signals and raw audio signals.

[0030] The noise signal is standardized to obtain a standardized noise signal, which is then encoded to obtain a coded noise signal.

[0031] The encoded noise signal is decoded, and energy balance coefficients and time delay compensation parameters are generated based on the noise signal and the target control area parameters.

[0032] After performing frequency-segment amplitude shaping and time delay compensation on the standardized noise signal, a phase reversal operation is performed to generate an inverse noise signal;

[0033] Based on the original audio signal and the tunnel sound reflection model, the reverberation component in the tunnel is predicted. After phase reversal, the reverse reverberation signal is generated, and a reverberation gating coefficient is introduced for weighted control to obtain the actual reverse reverberation signal.

[0034] The original audio signal, the inverse noise signal, and the actual inverse reverberation signal are superimposed to obtain the final audio signal.

[0035] Thirdly, the present invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of an audio enhancement method for a downhole broadcasting system as described in the second aspect.

[0036] Fourthly, the present invention provides a computer device including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of an audio enhancement method for an underground broadcasting system as described in the second aspect.

[0037] The above one or more technical solutions have the following beneficial effects:

[0038] This invention generates inverse noise and inverse reverberation signals in real time and utilizes the principle of destructive interference to effectively reduce the impact of environmental noise and reverberation, thereby improving broadcast sound quality, clarity, and coverage. This solves the problem of noise reduction and reverberation suppression in complex environments using existing technologies.

[0039] Compared to traditional noise reduction methods that rely on global filtering or single suppression, this invention employs an active noise cancellation mechanism based on acoustic wave destructive interference. A third signal processing unit performs spectral and phase analysis on the collected environmental noise, and a control strategy is used to perform amplitude shaping on different frequency bands, along with time delay compensation and phase alignment. This generates an inverse noise signal that matches the amplitude of the main components of the environmental noise but has the opposite phase. This inverse noise signal then undergoes destructive interference with the environmental noise within a preset control area. This reduces noise masking while minimizing the weakening of the effective voice content of the broadcast, thereby improving the clarity and coverage consistency of underground broadcasts.

[0040] The system can analyze the reverberation components of audio signals in the tunnel, generate a reverse reverberation signal through the fourth signal processing unit, and effectively suppress the reverberation effect through interference, thereby improving the clarity of broadcasting and voice transmission in the tunnel.

[0041] The system can analyze the reverberation component of audio signals within the tunnel, generate a reverse reverberation signal through the fourth signal processing unit, and introduce reverberation intensity assessment and gating coefficients to achieve adaptive start / stop and intensity adjustment of the reverse reverberation branch. Specifically, when reverberation is significant, suppression is enhanced to reduce reflection tails and improve speech intelligibility; when reverberation is weak or under open / semi-open propagation conditions, the reverse reverberation output is appropriately reduced or turned off to avoid sound quality degradation caused by overcompensation. Simultaneously, stability mechanisms such as amplitude limiting / rate of change constraints and channel reestimation are incorporated to improve the long-term operational safety and auditory consistency of the system. Attached Figure Description

[0042] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0043] Figure 1 This is a block diagram of the audio enhancement system structure of an underground broadcasting system according to an embodiment of the present invention;

[0044] Figure 2 This is a flowchart of an audio enhancement method for an underground broadcasting system according to an embodiment of the present invention. Detailed Implementation

[0045] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0046] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0047] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0048] Terminology Explanation:

[0049] Environmental noise cancellation: This involves using technical means to reduce or eliminate noise interference in the environment, making signals (such as sound and images) clearer. Environmental noise cancellation technology is mainly used to improve signal quality in noisy environments, especially in fields such as communications, audio playback, and hearing devices.

[0050] Reverb suppression: Improves the clarity and intelligibility of audio signals by reducing or eliminating the reverberation effect caused by sound reflections in the environment. Reverb typically occurs in enclosed or semi-enclosed spaces, especially on hard surfaces such as walls, ceilings, and floors. After sound is reflected, multiple signals reach the listener's ears at different times, causing the sound to become blurred and overlapping, making originally clear audio information difficult to discern.

[0051] Example 1

[0052] like Figure 1 As shown in the figure, this embodiment discloses an audio enhancement system for an underground broadcasting system, including a signal acquisition unit, a first signal processing unit, a second signal processing unit, a third signal processing unit, a fourth signal processing unit, a fifth signal processing unit, and an audio playback unit.

[0053] (a) Signal Acquisition Unit

[0054] The signal acquisition unit includes a noise acquisition unit, used to acquire audio data within the mine roadway. The audio data includes noise signals and raw audio signals.

[0055] In this embodiment, the original audio signal It is directly acquired in real time from the digital audio output interface of the broadcast system, that is, the digital stream of the broadcast audio that is currently playing, without the need for additional acquisition.

[0056] The noise acquisition unit is positioned within the speaker's coverage area and close to the front of the speaker's acoustic axis or along the main propagation direction of the alleyway to acquire ambient noise consistent with the sound field at the actual playback point of the speaker. The noise acquisition unit includes at least one explosion-proof microphone, which is mounted using an impact-resistant bracket to ensure stability and continuously record ambient noise. The noise signal may include, but is not limited to, low-frequency noise, high-frequency noise, or a combination of both. The noise is converted into an electrical signal via the microphone, generating a real-time noise audio stream, which is transmitted to the first signal processing unit via a data bus.

[0057] In some implementations, the noise acquisition unit can be fixed to the side wall or roof of the tunnel, or the fixed position can be flexibly selected according to the actual situation, without specific limitations.

[0058] In some implementations, preferably, the noise acquisition unit is positioned within a straight-line distance of 3-20 meters from the corresponding loudspeaker in areas with a high concentration of people.

[0059] In some implementations, the sampling rate of the noise acquisition unit can be set to 48kHz, and the dynamic range ≥110dB. The sampling rate and dynamic range of the noise acquisition unit can be flexibly set according to actual conditions and are not specifically limited.

[0060] (ii) First Signal Processing Unit

[0061] The first signal processing unit is used to standardize the noise signal to obtain a standardized noise signal, which is then encoded to obtain a coded noise signal.

[0062] In this embodiment, the first signal processing unit performs standardization processing on the acquired audio data (noise audio data) to obtain standardized noise audio data, which is then encoded to obtain encoded noise audio data.

[0063] The audio data is standardized, specifically as follows:

[0064] (1) Calculate the maximum amplitude for each audio signal (noise signal and reverberation signal). The calculation formula is as follows:

[0065]

[0066] in, Indicates the time of the audio signal The value on, Indicates all points in time The maximum absolute amplitude of the signal is shown in the figure. This maximum amplitude value will be used in the subsequent normalization process.

[0067] (2) Apply a linear method to the audio signal based on the calculated maximum amplitude to unify the signal intensity. The formula is:

[0068]

[0069] in, This represents the standardized audio signal. This represents the maximum amplitude of the original signal. This represents the target standard amplitude value. The value can be adjusted according to the actual situation to achieve the best noise reduction effect.

[0070] The standardized noise audio data (noise signal) is encoded into AAC or ADTS format. The encoded audio data (coded noise audio data) is first packaged into data packets, each containing the time sequence information of the audio data and necessary synchronization information. The encoded audio data is then transmitted in real time to the second signal processing unit via a communication unit.

[0071] The communication unit uses at least one of wireless communication and wired communication methods to transmit data packets, and can package and encrypt data packets during transmission to ensure the security of transmission and the integrity of data.

[0072] In some implementations, wireless communication may employ Wi-Fi, Bluetooth, or a dedicated wireless transmission protocol, while wired communication may employ Ethernet, fiber optic cable, coaxial cable, CAN bus, RS485 bus, or other industrial communication links, without specific limitations.

[0073] In some implementations, modulation and demodulation techniques (such as OFDM modulation) are used during data transmission to optimize signal transmission quality and reduce the effects of noise and interference.

[0074] (III) Second Signal Processing Unit

[0075] The second signal processing unit is used to decode the coded noise signal and generate energy balance coefficient and time delay compensation parameters based on the noise signal and target control area parameters. The standardized noise signal and the original audio signal are then transmitted to the third signal processing unit and the fourth signal processing unit, respectively.

[0076] In this embodiment, after receiving the encoded audio data transmitted through the communication unit, the second signal processing unit first performs decoding processing. The second signal processing unit uses a decoder to decode the received audio data. After decoding, the second signal processing unit transmits the noise signal and the original audio signal to the third signal processing unit and the fourth signal processing unit, respectively.

[0077] Furthermore, after the second signal processing unit completes the decoding of the noise signal, the system enters the control strategy analysis stage. Based on the decoded noise signal, the second signal processing unit comprehensively analyzes the signal's timestamp, energy distribution, and spatial correlation characteristics to determine the main noise sources in the environment and their impact on the broadcast coverage area. Specifically, the second signal processing unit performs time alignment and energy statistical analysis on the noise signal, calculating the average energy, peak energy, and variation trend of each signal within different time windows to determine the dominant noise region in space and time. Simultaneously, based on the spatial correspondence between the noise acquisition unit and the broadcast loudspeakers, the contribution weight of each noise source to the target control area is determined.

[0078] Furthermore, determining the contribution weight of each noise level to the target control area specifically includes:

[0079] Let the first The connection coefficient of the noise acquisition unit corresponding to each target control area is: When the first The noise acquisition unit serves the first When there is a target control area ;otherwise The connection factor is predetermined during the system installation or commissioning phase based on the layout of the noise acquisition unit and the loudspeaker.

[0080] Let the first The effective energy of each noise acquisition unit within the current analysis window is: Then the first The acquisition unit for the first... The contribution weight of each target control area can be expressed as:

[0081]

[0082] in, Indicates the first The acquisition unit for the first... Contribution weights of each target control area For the first The first target control area corresponding to the first The connection coefficient of each noise acquisition unit For the first The effective energy of each noise acquisition unit within the current analysis window.

[0083] Based on the aforementioned weights, the second signal processing unit performs weighted fusion of the control parameters corresponding to each noise acquisition unit to obtain the signal processing parameters for the first noise acquisition unit. Comprehensive control parameters for each target control area.

[0084] Based on this, the second signal processing unit generates a set of control parameters for subsequent inverse noise signals, including but not limited to: energy balance coefficient. and delay compensation parameters The control parameters are used to constrain the amplitude and timing of the subsequently generated reverse audio signal to avoid overcompensation or undercompensation of the reverse audio output by a single noise source. The control parameters are transmitted to the third and fourth signal processing units via the internal control interface as the basis for controlling the generation of the reverse noise signal.

[0085] Furthermore, the control parameters can be obtained in the following manner:

[0086] (1) Energy balance coefficient

[0087]

[0088] in, This represents the weighted noise energy of the target control region. Indicates the contribution weight of the target control area. Indicates the first The waveform of noise (or noise components separated by pre-processing) acquired by each acquisition unit over time.

[0089] RMS is a metric that measures the ratio of effective amplitude to average energy intensity of a signal, expressed as:

[0090]

[0091] in, For the root mean square, in the window The term "internal" is a commonly used metric for measuring the "effective amplitude / average energy intensity" of a signal. This represents the audio signal to be analyzed. Indicates the length of the analysis time window. This indicates the start time of the current analysis time window. It represents the square of the instantaneous amplitude of the signal.

[0092] Calculate the broadcast reference signal energy and determine it based on the desired signal-to-noise ratio target. The energy balance coefficient is determined as follows:

[0093]

[0094]

[0095] in, For broadcast reference signal energy, Indicates the broadcast reference signal; This is a limiting function that restricts the output to a safe range. This represents the compensation adjustment coefficient, used to correct the compensation intensity based on the target signal-to-noise ratio. Its value is determined according to the target signal-to-noise ratio. Pre-set or adaptively determined, This represents the target signal-to-noise ratio threshold that the system hopes to achieve, where... Indicates the signal-to-noise ratio. Indicates the target value; Minimum compensation strength (to prevent complete lack of compensation); Maximum compensation strength (to prevent overcompensation, distortion, howling, or instability).

[0096] (2) Delay compensation parameters

[0097] When multiple acquisition channels exist, the position of the main cross-correlation peak is determined for each channel. And take their weighted average as a unified time delay compensation parameter:

[0098]

[0099] in, Used to provide a unified time delay compensation parameter for inverse noise signals / inverse reverberation signals; For the first The contribution weight of each acquisition channel, Indicates the first The latency values ​​for each acquisition channel are obtained by calculating the position of the main peak through cross-correlation. The contribution weights corresponding to each acquisition channel are normalized to satisfy:

[0100]

[0101] (iv) Third signal processing unit

[0102] The third signal processing unit is used to perform frequency band amplitude shaping and time delay compensation on the standardized noise signal, and then perform a phase reversal operation to generate an inverse noise signal.

[0103] In this embodiment, after receiving the standardized noise signal, the third signal processing unit first performs spectral analysis on it, using Fourier transform to decompose the noise signal into multiple frequency components to obtain the frequency distribution characteristics of the noise signal. Subsequently, the third signal processing unit extracts the amplitude and initial phase information corresponding to each frequency component, which are used to characterize the intensity and temporal position relationship of each frequency component, respectively. After completing the extraction of frequency components, amplitude, and phase parameters, the third signal processing unit, in conjunction with the energy balance coefficient generated by the second signal processing unit, performs frequency band amplitude shaping on each frequency component; then, based on the time delay compensation parameters, it performs time alignment on the shaped noise signal so that the subsequently generated reverse noise signal can maintain temporal and phase correspondence with the environmental noise within the target control area. Finally, a phase reversal operation is performed on the noise signal after amplitude shaping and time delay compensation to generate the reverse noise signal.

[0104] Assume the linearly amplified noise signal is In the third signal processing unit, a mathematical model of the noise signal is established, which is expressed as:

[0105]

[0106] in, Indicates the amplitude of environmental noise. Indicates the frequency of ambient noise. Represents the time constant. This represents the initial phase of the frequency component.

[0107] After linearly amplifying and modeling the noise signal, the third signal processing unit divides the noise signal into multiple frequency sub-bands according to the spectral distribution characteristics of the noise signal, and applies amplitude adjustment coefficients to different frequency sub-bands to enhance the reverse cancellation effect of the main noise frequency band.

[0108] Specifically, a noise signal can be represented as a superposition of multiple frequency components:

[0109]

[0110] in, Indicates the first The amplitude of each frequency component, Indicates the first The angular frequency of each frequency component. Indicates the first The initial phase of each frequency component, Indicates the number of frequency components.

[0111] The third signal processing unit, in conjunction with the energy balance coefficient generated by the second signal processing unit, applies amplitude shaping weights to each frequency component. The noise signal model after frequency band amplitude shaping is obtained:

[0112]

[0113] Amplitude shaping weight According to the energy balance coefficient The energy proportion of the frequency band components is determined by the following formula:

[0114]

[0115] in, Indicates the first The energy percentage of each frequency component This represents the weight allocation function.

[0116] Since the propagation of noise signals in the roadway and the system processing introduce time delay, in order to make the reverse noise signal phase-aligned with the ambient noise in the preset control area, the third signal processing unit introduces time compensation on the noise signal after frequency band amplitude shaping according to the time delay compensation parameter, so as to achieve phase alignment between the reverse noise and the ambient noise at the target control point.

[0117] The target control point can be a single or multiple spatial locations, and the control area can be defined by a set of locations of one or more microphones. When there are multiple target control points, the system can weight and summarize the error signals of each control point according to preset weights to form a comprehensive evaluation quantity for control strategy analysis and parameter updates. The weights can be set according to the area of ​​personnel activity, the main direction of sound propagation, or the geometric relationship between each point and the loudspeaker, thereby achieving point-like, linear, or area-like active sound field optimization in the roadway.

[0118] Let the compensation time be... Then, the noise signal after introducing time delay compensation can be expressed as:

[0119]

[0120] Through the aforementioned time compensation, the reverse noise signal is synchronized with the environmental noise signal on the time axis when it propagates to the preset control area, and the phase cancellation condition is satisfied, thereby improving the effectiveness of reverse interference.

[0121] After completing the frequency band amplitude shaping and time delay compensation, the third signal processing unit performs a phase reversal operation on the noise signal to generate a reverse noise signal with a phase difference of 180° from the original noise signal:

[0122]

[0123] The reverse noise signal maintains a correspondence with the ambient noise in terms of frequency and amplitude characteristics, and undergoes destructive interference with the ambient noise during propagation, achieving the effect of noise suppression. Subsequently, the reverse noise signal is transmitted to the fifth signal processing unit.

[0124] (v) Fourth Signal Processing Unit

[0125] The fourth signal processing unit is used to predict the reverberation component in the tunnel based on the original audio signal and the tunnel sound reflection model. After phase reversal, it generates a reverse reverberation signal and introduces a reverberation gating coefficient for weighted control to obtain the actual reverse reverberation signal.

[0126] In this embodiment, the fourth signal processing unit uses the original audio signal y(t) currently being played by the broadcast system as a reference signal and predicts the reverberation component using the established tunnel sound reflection model. As an observation signal.

[0127] because Simultaneously including both direct sound components and multipath reflection components, the fourth signal processing unit... and Cross-correlation analysis is performed to identify the arrival time of the direct sound and the time delay of each significant reflection peak, thereby enabling dynamic extraction and differentiation of reverberation components. The main peak in the cross-correlation function corresponds to the direct sound path, and the multiple secondary peaks following the main peak correspond to the delay characteristics of the reflection path. Based on this, the system can strip away the component corresponding to the direct sound to obtain reverberation reference information dominated by reflected sound, which is then used for subsequent reflection characteristic modeling and reverse reverberation signal generation, allowing the reverberation parameters to be updated in real time according to changes in playback content and environment.

[0128] The fourth signal processing unit calculates and models the acoustic wave reflection characteristics within the tunnel using time-domain or frequency-domain analysis methods. The extraction of reverberation components depends on the delay, reflection path, and intensity information of the captured signal. This information is used to obtain the delay and attenuation coefficients of each reflection path in the tunnel through mathematical modeling. Based on this, a mathematical model of the reverberation signal is established in the fourth signal processing unit, specifically as follows:

[0129] Assuming the tunnel is a straight segment or a passage formed by connecting multiple straight segments, the length is... ,width and height These are the main geometric parameters of the tunnel. If the tunnel is a straight section, the sound wave propagates directly within the straight section, and reflection mainly occurs on the tunnel wall. If there are bends in the tunnel, the bends will affect the propagation of the sound wave, causing sound wave reflection and refraction. Therefore, it is necessary to model the tunnel based on the specific bend angle and length.

[0130] The walls, floors, and ceilings within a tunnel typically possess different reflective properties. Each surface has a sound absorption coefficient. The reflection coefficient is used to describe the degree to which sound is reflected when it comes into contact with a surface. The relationship with the sound absorption coefficient is as follows:

[0131]

[0132] The higher the reflection coefficient, the stronger the sound reflection; conversely, the higher the sound absorption, the weaker the reflection.

[0133] Once the structure of the tunnel space is determined, the propagation path of sound waves within the tunnel can be calculated. The propagation path includes the direct path and the path after reflection.

[0134] Furthermore, the direct path: the straight-line propagation path of a sound wave from the sound source to the receiving point; the delay time can be calculated from the distance the sound wave travels. Let... Location of the sound source Given the location of the receiving point, the propagation distance of the direct path is... for:

[0135]

[0136] Direct path delay time for:

[0137]

[0138] in, It is the speed of sound in the air, usually 340 m / s.

[0139] Furthermore, the reflection path: the reflection path of sound waves within the tunnel is quite complex, requiring multiple reflections before finally reaching the receiving point. The propagation distance of each reflection path... This includes the total length of multiple reflections. For a simple reflection path, the total propagation distance from the reflection point is:

[0140]

[0141] in, , , It is the propagation distance of each reflection.

[0142] By comparing the amplitude of the reference signal (original audio signal) with the amplitude of the captured reflected signal, the fourth signal processing unit can calculate the attenuation of each reflection path. The fourth signal processing unit analyzes the attenuation of each reflection path, that is, the ratio of the intensity of the reflected signal to the intensity of the original signal, to obtain the attenuation coefficient, calculated using the following formula:

[0143]

[0144] in, For the first The intensity of the reflected signal, The intensity of the initial reflected signal.

[0145] The fourth signal processing unit performs cross-correlation analysis on the raw audio signal and the observed signal. The main peak in the cross-correlation function corresponds to the direct sound path, and the secondary peaks correspond to the reflection paths. The time positions of the secondary peaks are used to determine the reflection path delay. For the first The propagation delay of a reflection path is expressed as follows:

[0146]

[0147] in, For the first The propagation distance of a reflection path, The speed at which sound travels through the air is approximately 340 m / s.

[0148] Select tunnel CAD / parametric geometry (length) ,width ,high The boundary conditions, such as the sound absorption coefficients of walls, ceilings, and floors, are imported into tools like ODEON, CATT-Acoustic's TUCT module, or COMSOL acoustic module. Based on ray tracing / hybrid acoustic methods, the echo map or impulse response of the space is output, thereby directly obtaining the effective reflection sequence and its... , and The initial estimate is then used to adjust the parameters online by combining the real-time cross-correlation results to adapt to the time-varying reflection characteristics of the downhole environment.

[0149] Not all reflection paths significantly affect reverberation suppression. Some reflection paths may have very long propagation distances or large attenuation coefficients, thus contributing negligibly to the final reverberation signal. A threshold can be determined empirically or through analysis. If the attenuation coefficient of a certain reflection path Exceeding this threshold, or the propagation distance of the path Beyond a certain maximum distance, the contribution of that path to the final reverberation can be considered negligible. If the attenuation coefficient is greater than... The path, that is, The contribution of this path can be ignored.

[0150] After determining the tunnel structure, sound wave propagation path, delay, attenuation coefficient, and negligible path, the fourth signal processing unit can establish a mathematical model of the reflection path (tunnel sound reflection model). This model will be used for further reverberation signal analysis and generation of reverse reverberation signals.

[0151] This can be expressed using a mathematical model formula:

[0152]

[0153] in, For reverberation signal, The original audio signal. For the first Attenuation coefficient of each reflection path, For the first The propagation delay of each reflection path, Indicates the number of reflection paths. For the signal at the specified acquisition point ( The location is chosen at the point where the flow of people in the alley is most concentrated. is the time constant.

[0154] The fourth signal processing unit, based on the delay and attenuation parameters of each reflection path of the noise signal, performs cross-correlation analysis from... After separating the pure reverberation component, inverse signals are generated for each reflection path (by reversing the phase to generate a reverberation signal that is completely symmetrical and opposite to the original reverberation signal). The generated inverse reverberation signal forms a waveform completely opposite to the original reverberation signal in the time domain, and the phase of the inverse reverberation signal differs from that of the original reverberation signal by 180 degrees. At this point, the generated inverse reverberation signal can be expressed by the following formula:

[0155]

[0156] in, It is a reverse reverberation signal. and It is the inverse parameter corresponding to the original reverberation component. After obtaining the inverse reverberation signal, the system will transmit the signal to the fifth signal processing unit.

[0157] Furthermore, the reverse reverberation signal introduces a reverberation gating coefficient. Weighted control is implemented to achieve adaptive start / stop and intensity adjustment of the reverse reverberation branch under different reverberation intensities.

[0158] Based on the energy ratio of direct sound and reverberation sound The reverberation intensity index can be obtained by cross-correlation of the energy ratio of the main peak and the secondary peak. The reverberation gating coefficient is then obtained through gating mapping. , represented as:

[0159]

[0160] in, The slope The threshold value is used.

[0161] To avoid side effects such as muffled speech and compressed spatial perception caused by applying excessively strong reverse reverberation under conditions of weak reverberation or open / semi-open propagation, the second signal processing unit further calculates the reverberation intensity index and generates reverberation gating coefficients. , This is used for adaptive control of the start / stop and intensity of the reverse reverberation branch, thereby avoiding overcompensation and sound quality degradation under weak reverberation conditions. The reverberation intensity index can be obtained based on the direct-to-reverberation energy ratio (DRR) or the cross-correlation ratio of the main peak to the secondary peak energy, or the sum of the secondary peak energies, between the playback reference signal and the reverberation acquisition signal. When the reverberation intensity is below a threshold, Approaching 0, to reduce or turn off the reverse reverberation output; when the reverberation intensity is above the threshold, Approaching 1 to enhance the reverse reverb output.

[0162] Specifically, the reverse reverberation signal can be represented as:

[0163]

[0164] in, This is the reverse reverberation signal from the actual output to the overlay / playback link after adding the gating factor.

[0165] when At lower levels, the system reduces or disables the inverse reverberation output to avoid sound quality degradation caused by overcompensation under weak reverberation conditions; when At higher levels, the system enhances the back reverberation output to suppress significant reflection tails, thereby improving speech intelligibility and localization. The back reverberation signal transmitted to the fifth signal processing unit at this time is... .

[0166] (vi) Fifth Signal Processing Unit

[0167] The fifth signal processing unit is used to superimpose the original audio signal, the inverse noise signal, and the actual inverse reverberation signal to obtain the final audio signal.

[0168] In this embodiment, the fifth signal processing unit superimposes the original audio signal, the inverse noise signal, and the inverse reverberation signal:

[0169]

[0170] in, The signal is the superimposed signal. The original audio signal. This is a reverse noise signal. This is a reverse reverberation signal.

[0171] Superimposed signal There may be occasional instances of excessively high peak values ​​or dynamic range exceeding limits. To ensure speaker output safety, system stability, and consistent sound quality, the fifth signal processing unit... After performing amplitude limiting and smoothing, the final output audio signal is obtained. For example, this can be achieved through peak limiting: when When the signal exceeds a preset threshold, a limit is applied; otherwise, the original amplitude remains unchanged, thus avoiding distortion or abnormal sound pressure levels caused by overcompensation. The processed signal is denoted as:

[0172]

[0173] in, This is the final audio signal after clipping. This represents the amplitude limiting function.

[0174] The final audio signal generated by the fifth signal processing unit is transmitted through the audio playback unit. The signal is output to the tunnel environment. Since the reverse noise signal and the reverse reverberation signal are out of phase and aligned with the ambient noise component and the reverberation reflection component, respectively, when they meet, they will cancel each other out in the tunnel through the destructive interference effect, reducing or eliminating the noise and reverberation components in the tunnel. That is, in response to the real-time noise in the external environment, the reverse sound wave is generated to cancel the ambient noise, thereby improving the clarity of the audio signal in the tunnel.

[0175] This invention addresses high-noise, high-reflection scenarios in mine roadways. By separately acquiring and modeling noise and reverberation, and under the constraints of control strategies (such as noise source determination and energy balance parameters), it generates reverse noise and reverse reverberation signals. Then, it performs frequency band amplitude shaping, time delay compensation, and phase alignment to make them cancel each other out with the environmental noise component and the reflected reverberation component in the control area, thereby improving broadcast intelligibility and coverage consistency.

[0176] The present invention achieves the following objectives: (1) Cancellation of environmental noise. By detecting environmental noise signals through a noise acquisition unit, the system generates an inverse noise signal with the same energy as the environmental noise but a phase difference of 180°. The two sound waves interfere in the tunnel, significantly reducing the noise component in the target control area, thereby achieving the purpose of noise reduction. (2) Suppression of reverberation. The system can establish a tunnel sound reflection model, predict the reverberation component in the tunnel online, generate an inverse reverberation signal by phase reversal, and effectively suppress the reverberation effect through interference, thereby improving the clarity of broadcasting and voice transmission in the tunnel.

[0177] The system analyzes the captured reverberation signals in real time and extracts the reflection components. Based on the delay, attenuation coefficient, and frequency characteristics of the reflected sound, it generates an inverse reverberation signal with opposite phase to these reverberation signals. By adjusting the amplitude, delay, and frequency of the inverse reverberation signal, it causes destructive interference with the reverberation signals in the environment in space, thereby suppressing reverberation and improving audio quality. This invention can enhance the sound quality of underground broadcasting systems, reduce environmental noise, suppress reverberation, and improve coverage.

[0178] Therefore, this invention improves the propagation quality of audio signals by using reverse noise signals to cancel environmental noise and reverse reverberation signals to suppress reverberation. It is particularly suitable for the special environments of underground mines, characterized by high noise, strong reflections, and varied structures. The system can improve voice clarity and coverage consistency during routine broadcasts and safety management information dissemination, and can also more clearly and accurately transmit critical instructions and evacuation guidance information in emergency scenarios such as hazardous situations, improving information accessibility and recognizability, ensuring worker safety, and enhancing management efficiency.

[0179] Example 2

[0180] like Figure 2 As shown, this embodiment discloses an audio enhancement method for an underground broadcasting system, including:

[0181] Acquire audio data from within a mine roadway; the audio data includes noise signals and raw audio signals.

[0182] The noise signal is standardized to obtain a standardized noise signal, which is then encoded to obtain a coded noise signal.

[0183] The encoded noise signal is decoded, and energy balance coefficients and time delay compensation parameters are generated based on the noise signal and the target control area parameters.

[0184] After performing frequency-segment amplitude shaping and time delay compensation on the standardized noise signal, a phase reversal operation is performed to generate an inverse noise signal;

[0185] Based on the original audio signal and the tunnel sound reflection model, the reverberation component in the tunnel is predicted. After phase reversal, the reverse reverberation signal is generated, and a reverberation gating coefficient is introduced for weighted control to obtain the actual reverse reverberation signal.

[0186] The original audio signal, the inverse noise signal, and the actual inverse reverberation signal are superimposed to obtain the final audio signal.

[0187] Example 3

[0188] The purpose of this embodiment is to provide a computing device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the method of Embodiment 2.

[0189] Example 4

[0190] The purpose of this embodiment is to provide a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, performs the steps of the method of Embodiment 2.

[0191] The steps and methods involved in the apparatuses of Embodiments 3 and 4 above correspond to those in Embodiment 1. For specific implementation details, please refer to the relevant description section of Embodiment 1. The term "computer-readable storage medium" should be understood as a single medium or multiple media including one or more instruction sets; it should also be understood as including any medium capable of storing, encoding, or carrying an instruction set for execution by a processor and enabling the processor to perform any of the methods in this invention.

[0192] Those skilled in the art will understand that the modules or steps of the present invention described above can be implemented using general-purpose computer devices. Optionally, they can be implemented using computer-executable program code, thereby allowing them to be stored in a storage device for execution by a computer device, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. The present invention is not limited to any particular combination of hardware and software.

[0193] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0194] While the specific embodiments of the present invention have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of the present invention are still within the scope of protection of the present invention.

Claims

1. An audio enhancement system for an underground broadcasting system, characterized in that, include: A signal acquisition unit is used to acquire audio data in a mine roadway; the audio data includes noise signals and raw audio signals. The first signal processing unit is used to standardize the noise signal to obtain a standardized noise signal, which is then encoded to obtain a coded noise signal. The second signal processing unit is used to decode the coded noise signal and generate energy balance coefficient and time delay compensation parameter based on the noise signal and target control area parameters. The standardized noise signal and the original audio signal are transmitted to the third signal processing unit and the fourth signal processing unit, respectively. The third signal processing unit is used to perform frequency band amplitude shaping and time delay compensation on the standardized noise signal, and then perform a phase reversal operation to generate an inverse noise signal. The fourth signal processing unit is used to predict the reverberation component in the tunnel based on the original audio signal and the tunnel sound reflection model, generate the reverse reverberation signal after phase inversion, and introduce reverberation gating coefficients for weighted control to obtain the actual reverse reverberation signal. The fifth signal processing unit is used to superimpose the original audio signal, the inverse noise signal, and the actual inverse reverberation signal to obtain the final audio signal; The frequency band amplitude shaping specifically involves: dividing the standardized noise signal into multiple frequency components, applying amplitude shaping weights to each frequency component based on the energy balance coefficient to obtain the frequency band amplitude-shaped noise signal; and introducing time delay compensation into the frequency band amplitude-shaped noise signal to obtain the time delay-compensated noise signal. The tunnel acoustic reflection model is represented as follows: in, For reverberation signal, y The original audio signal. For the first Attenuation coefficient of each reflection path, For the signal at the specified acquisition point, For the first The propagation delay of each reflection path, The number of reflection paths, It is a time constant; The attenuation coefficient is expressed as: in, The attenuation coefficient is... For the first The intensity of the reflected signal, The intensity of the initial reflected signal; The propagation delay is expressed as: in, To delay the transmission time, For the first The propagation distance of a reflection path, c This is the speed at which sound travels through the air.

2. The audio enhancement system for an underground broadcasting system as described in claim 1, characterized in that, The second signal processing unit performs a comprehensive analysis of the timestamp, energy distribution, and spatial correlation characteristics of the noise signal based on the decoded noise signal, and generates an energy balance coefficient and a time delay compensation parameter.

3. The audio enhancement system for an underground broadcasting system as described in claim 1, characterized in that, The superimposed signals are then limited to obtain the final audio signal.

4. An audio enhancement method for an underground broadcasting system, employing an audio enhancement system for an underground broadcasting system as described in any one of claims 1-3, characterized in that, include: Acquire audio data from within a mine roadway; the audio data includes noise signals and raw audio signals. The noise signal is standardized to obtain a standardized noise signal, which is then encoded to obtain a coded noise signal. The encoded noise signal is decoded, and energy balance coefficients and time delay compensation parameters are generated based on the noise signal and the target control area parameters. After performing frequency-segment amplitude shaping and time delay compensation on the standardized noise signal, a phase reversal operation is performed to generate an inverse noise signal; Based on the original audio signal and the tunnel sound reflection model, the reverberation component in the tunnel is predicted. After phase reversal, the reverse reverberation signal is generated, and a reverberation gating coefficient is introduced for weighted control to obtain the actual reverse reverberation signal. The original audio signal, the inverse noise signal, and the actual inverse reverberation signal are superimposed to obtain the final audio signal.

5. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in the audio enhancement method for a downhole broadcasting system as described in claim 4.

6. A computer device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the audio enhancement method for a downhole broadcasting system as described in claim 4.

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