Ocean reverberation time domain waveform implementation method and system based on convolution operation

Abstract

The invention provides an ocean reverberation time domain waveform realization method and system based on convolution operation, and the method comprises the steps: generating a one-dimensional random number sequence meeting a random process, and the data size of the random sequence is the same as the data size of a reverberation time domain waveform to be realized; generating a sound source signal time domain waveform; performing convolution operation on the random number sequence and the sound source signal time domain waveform to obtain a stabilized time domain waveform signal subjected to reverberation intensity stabilization processing; generating an ocean reverberation intensity attenuation curve according to the reverberation intensity theoretical model; and performing intensity weighting on the stabilized time-domain waveform signal subjected to reverberation intensity stabilization processing by using the attenuation curve to obtain a reverberation time-domain waveform. The method has the advantages that cross superposition of scattering echoes of different discrete points does not need to be considered; the calculation speed is high, the requirement for the data cache capacity is small, and the amplitude and the phase of each discrete point echo and the broadening of a transmitted signal do not need to be calculated; the method is suitable for realizing reverberation time domain waveforms in various waveguide environments.

Description

Technical Field

[0001] The present application belongs to the field of underwater acoustic physics and underwater acoustic signal processing, and specifically relates to a method and system for realizing ocean reverberation time domain waveform based on convolution operation. Background Art

[0002] At present, there are three main methods to realize reverberation signals: point scattering superposition, broadband inverse Fourier transform and reverberation waveform generation based on reverberation statistical characteristics.

[0003] The discrete point scattering method primarily discretizes the scattering points in space. First, the time-domain signal propagates from the sound source to the scattering point, experiencing intensity attenuation and phase variation. Second, the scattering loss and random phase variations caused by superposition scattering are considered. Finally, the point scattering method is used during the propagation from the scattering point to the receiving location. This method assumes that the phase variations caused by scattering at discrete points in the scattering process are random processes. This method places high demands on device storage space due to the sampling rate and pulse width requirements of the sound source signal, necessitating a large cache space on the computing device. This large cache size also reduces computational speed.

[0004] The broadband inverse Fourier transform method can only obtain broadband time-domain waveform signals. The frequency interval is inversely proportional to the time length of the time-domain waveform. Therefore, the smaller the frequency interval and the denser the frequency sampling, the greater the roughness of the calculated time-domain waveform. The coarser the frequency sampling interval, the more difficult it is to characterize the information of the corresponding bandwidth.

[0005] The statistical characteristics of reverberation stationary signals are based on the assumption that the phase of the reverberation stationary random signal is uniformly distributed. A time series with a random phase distribution is generated as the reverberation stationary random signal. The time-varying reverberation intensity sequence is then multiplied one-to-one with the stationary random signal to change the instantaneous amplitude, resulting in the reverberation time domain waveform. This generation method is relatively simple and crude, unable to represent more reverberation characteristics beyond intensity, and lacks physical significance. Summary of the Invention

[0006] The purpose of this application is to overcome the defects of the existing reverberation time domain waveform realization method, which is slow, requires high prediction buffer space, and carries little reverberation characteristic information.

[0007] To achieve the above objectives, this application proposes a method for realizing ocean reverberation time domain waveform based on convolution operation, including:

[0008] Step 1: Generate a one-dimensional random number sequence that satisfies the random process. The data volume of the random sequence is the same as the data volume of the reverberation time domain waveform to be realized;

[0009] Step 2: Generate the time domain waveform of the sound source signal;

[0010] Step 3: performing a convolution operation on the random number sequence and the time domain waveform of the sound source signal to obtain a stabilized time domain waveform signal with stabilized reverberation intensity;

[0011] Step 4: Generate the ocean reverberation intensity attenuation curve based on the reverberation intensity theoretical model;

[0012] Step 5: Using the ocean reverberation intensity attenuation curve, intensity-weight the stabilized time-domain waveform signal that has undergone the reverberation intensity stabilization process to obtain a reverberation time-domain waveform.

[0013] As an improvement to the above method, the intensity weighting includes: multiplying the stabilized time domain waveform signal of the reverberation intensity stabilization processing by the reverberation intensity attenuation curve in a one-to-one temporal correspondence to achieve an inverse stabilization processing process of the reverberation signal.

[0014] The present application also provides a system for realizing ocean reverberation time domain waveform based on convolution operation, which is realized based on the above method, and the system includes:

[0015] A random number sequence generation module is used to generate a one-dimensional random number sequence that satisfies a random process, wherein the data volume of the random sequence is the same as the data volume of the reverberation time domain waveform to be realized;

[0016] A sound source signal generating module is used to generate a time domain waveform of a sound source signal;

[0017] a module for generating a stabilized time-domain waveform signal, configured to perform a convolution operation on the random number sequence and the time-domain waveform of the sound source signal to obtain a stabilized time-domain waveform signal with a stable reverberation intensity;

[0018] A module for generating an ocean reverberation intensity attenuation curve is used to calculate and generate an ocean reverberation intensity attenuation curve based on a reverberation intensity theoretical model;

[0019] The reverberation time domain waveform generating module is used to perform intensity weighting on the stabilized time domain waveform signal after the reverberation intensity stabilization processing using the ocean reverberation intensity attenuation curve to obtain the reverberation time domain waveform.

[0020] Compared with the prior art, the advantages of this application are:

[0021] 1. The reverberation time domain waveform implementation method of the present application is simple, and the reverberation intensity decay curve is generated relatively quickly. Once the reverberation intensity decay curve and the form of the sound source emission signal are known, the corresponding reverberation time domain waveform can be generated without considering the cross-superposition of scattered echoes from different discrete points;

[0022] 2. Compared with the traditional form of discrete scattering point superposition, this application has a fast calculation speed and relatively small data cache capacity requirement. It does not need to calculate the amplitude and phase of the echo of each discrete point, nor the broadening of the transmitted signal.

[0023] 3. The reverberation time domain waveform proposed in this application is closer to the measured data and carries more reverberation characteristic information, including intensity attenuation characteristics, frequency characteristics, and statistical characteristics;

[0024] 4. This application is applicable to the realization of reverberation time domain waveforms in various waveguide environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Shown is a flow chart for realizing ocean reverberation time domain waveform;

[0026] Figure 2 The figure shows the generation of uniformly distributed random numbers (for the convenience of observation, 0.5s of data are given), which satisfy the uniform distribution.

[0027] Figure 3 The figure shows the form of a 300Hz sound source signal (1ms of data is provided for easy observation);

[0028] Figure 4 Shown is the Figure 2 Random number in Figure 3 The sound source signal shown is subjected to matched filtering to obtain a reverberation-stabilized signal;

[0029] Figure 5 Shown is the reverberation intensity decay curve;

[0030] Figure 6 Shown is the Figure 4 The reverberation-stabilized signal in Figure 5 The reverberation time domain waveform generated by the inverse stabilization of the reverberation intensity weighted shown;

[0031] Figure 7 Shown is the Figure 6 The reverberation intensity feature extraction result of the reverberation time domain signal shown;

[0032] Figure 8 Shown is the Figure 6 The reverberation spectrum feature extraction result of the reverberation time domain signal shown;

[0033] Figure 9 Shown is the Figure 6 The results of extracting statistical features of the reverberation envelope of the reverberation time domain signal are shown. DETAILED DESCRIPTION

[0034] The technical solution of this application is described in detail below with reference to the accompanying drawings.

[0035] This application provides a convolution-based ocean reverberation time-domain waveform realization method and system. This method implements the reverberation time-domain waveform through convolution operations. A convolution operation is performed on a random process and a sound source signal to obtain a stabilized signal similar to reverberation. The stabilized signal is then intensity-weighted by the reverberation intensity to obtain the ocean reverberation time-domain waveform. This method offers the advantages of fast computational speed and low computational cost, while also being able to reflect information such as the intensity characteristics of the ocean reverberation, the frequency characteristics of the sound source, and the statistical characteristics of the reverberation.

[0036] Example 1

[0037] like Figure 1 As shown, the method for realizing ocean reverberation time domain waveform based on convolution operation provided by this application includes:

[0038] Step 1: Generate a one-dimensional random number sequence that satisfies the random process. The data volume of the random sequence is the same as the data volume of the reverberation time domain waveform to be realized.

[0039] Step 2: Generate the time domain waveform of the sound source signal, which mainly controls the spectral characteristics of the reverberation;

[0040] In step 3, a convolution operation is performed on the random array generated in step 1 and the sound source signal generated in step 2 to obtain a stabilized time domain waveform signal of the reverberation intensity stabilized process.

[0041] Step 4: Calculate and generate the ocean reverberation intensity attenuation curve based on the reverberation intensity theoretical model. This curve determines the intensity characteristics of the reverberation time domain waveform.

[0042] In step 5, the reverberation intensity attenuation curve generated in step 4 is used to perform intensity weighting on the stabilized reverberation time domain waveform signal obtained in step 3. That is, the stabilized reverberation time domain waveform signal in step 3 is multiplied by the reverberation intensity one-to-one in time to realize the inverse stabilization process of the reverberation signal and finally obtain the reverberation time domain waveform.

[0043] The ocean reverberation time domain waveform implementation method based on convolution operation is verified using actual data:

[0044] Step 1: Generate random numbers that satisfy uniform distribution and get Figure 2 The results shown are for a random array length of 20 seconds and a sampling rate of 20 kHz. For ease of observation, 0.5 seconds of data are shown.

[0045] Step 2: Generate the time domain waveform of the 300Hz sound source signal, such as Figure 3 The single-frequency signal given has a frequency of 300 Hz and a sampling rate of 20 kHz. For ease of observation, 1 ms of data is given.

[0046] Step 3, yes Figure 2 The random array shown is Figure 3 The sound source signal shown in the figure is processed by convolution operation to obtain a time domain waveform signal with stable reverberation intensity, as shown in Figure 4 shown.

[0047] Step 4, generate Figure 3 The ocean reverberation intensity attenuation curve of the corresponding frequency of the sound source signal is shown in the figure. Figure 5 As shown, this is the attenuation curve of shallow sea reverberation intensity at 300Hz.

[0048] Step 5, yes Figure 4 The stabilized reverberation time domain waveform signal shown is Figure 5 The reverberation intensity attenuation curve shown in the figure is weighted to obtain Figure 6 The time domain waveform of shallow sea reverberation is shown.

[0049] Step 6, Extract Figure 6 The reverberation time domain waveform shown is extracted by data processing method to obtain the reverberation intensity attenuation curve (such as Figure 7 As shown), reverberation spectrum characteristics (such as Figure 8 ) and reverberation envelope statistical characteristics (as shown in Figure 9 The results are basically consistent with the preset results.

[0050] The ocean reverberation time domain waveform realization method based on convolution operation provided in this application can more realistically reflect the characteristics of ocean reverberation. The reverberation time domain waveform is realized by means of convolution operation. This method has a fast implementation method and low computational cost. It can invert the intensity characteristics, sound source frequency characteristics, reverberation phase information, etc. of the ocean reverberation, and provide theoretical support for reverberation suppression and active detection signal processing.

[0051] Example 2

[0052] The present application also provides a system for realizing ocean reverberation time domain waveform based on convolution operation, which is realized based on the above method, and the system includes:

[0053] A random number sequence generation module is used to generate a one-dimensional random number sequence that satisfies a random process, wherein the data volume of the random sequence is the same as the data volume of the reverberation time domain waveform to be realized;

[0054] A sound source signal generating module is used to generate a time domain waveform of a sound source signal;

[0055] a module for generating a stabilized time-domain waveform signal, configured to perform a convolution operation on the random number sequence and the time-domain waveform of the sound source signal to obtain a stabilized time-domain waveform signal with a stable reverberation intensity;

[0056] A module for generating an ocean reverberation intensity attenuation curve is used to calculate and generate an ocean reverberation intensity attenuation curve based on a reverberation intensity theoretical model;

[0057] The reverberation time domain waveform generating module is used to perform intensity weighting on the stabilized time domain waveform signal after the reverberation intensity stabilization processing using the ocean reverberation intensity attenuation curve to obtain the reverberation time domain waveform.

[0058] The present application may also provide a computer device comprising: at least one processor, memory, at least one network interface, and a user interface. The various components in the device are coupled together via a bus system. It will be understood that the bus system is used to enable communication between these components. In addition to a data bus, the bus system also includes a power bus, a control bus, and a status signal bus.

[0059] The user interface may include a display, a keyboard, or a pointing device, such as a mouse, a trackball, a touchpad, or a touch screen.

[0060] It is understood that the memory in the embodiments disclosed in the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories. Among them, the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory. The volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example and not limitation, many forms of RAM are available, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate synchronous DRAM (DDRSDRAM), enhanced synchronous DRAM (ESDRAM), synchronous link DRAM (SLDRAM), and direct RAM bus RAM (DRRAM). The memories described herein are intended to include, but are not limited to, these and any other suitable types of memory.

[0061] In some embodiments, the memory stores the following elements, executable modules or data structures, or a subset or an extension thereof: an operating system and applications.

[0062] The operating system includes various system programs, such as the framework layer, core library layer, and driver layer, which are used to implement various basic services and handle hardware-based tasks. Application programs include various application programs, such as media players and browsers, which are used to implement various application services. The program that implements the method of the embodiment of the present disclosure can be included in the application program.

[0063] In the above embodiment, the processor may also call a program or instruction stored in the memory, specifically, a program or instruction stored in the application program, to:

[0064] Perform the steps of the above method.

[0065] The above method can be applied to or implemented by a processor. The processor may be an integrated circuit chip with signal processing capabilities. During implementation, each step of the above method can be completed by hardware integrated logic circuits in the processor or by software instructions. The above processor may be a general-purpose processor, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic devices, discrete gate or transistor logic devices, or discrete hardware components. The above-disclosed methods, steps, and logic block diagrams can be implemented or executed. The general-purpose processor may be a microprocessor or any conventional processor. The steps of the above-disclosed method can be directly implemented and executed by a hardware decoding processor, or by a combination of hardware and software modules in the decoding processor. The software module can be located in a storage medium well-known in the art, such as random access memory, flash memory, read-only memory, programmable read-only memory, electrically erasable programmable memory, registers, etc. The storage medium is located in the memory, and the processor reads the information in the memory and, in conjunction with its hardware, completes the steps of the above method.

[0066] It is understood that the embodiments described herein may be implemented using hardware, software, firmware, middleware, microcode, or a combination thereof. For hardware implementation, the processing unit may be implemented in one or more application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), general-purpose processors, controllers, microcontrollers, microprocessors, or other electronic units or combinations thereof for performing the functions described herein.

[0067] For software implementation, the technology of the present application can be implemented by executing the functional modules (e.g., procedures, functions, etc.) of the present application. The software code can be stored in a memory and executed by a processor. The memory can be implemented in the processor or external to the processor.

[0068] The present application may also provide a non-volatile storage medium for storing a computer program. When the computer program is executed by a processor, each step in the above method embodiment can be implemented.

[0069] Finally, it should be noted that the above embodiments are intended only to illustrate the technical solutions of this application and are not intended to limit the scope of the present invention. Although this application has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions to the technical solutions of this application do not depart from the spirit and scope of the technical solutions of this application and should be encompassed by the claims of this application.

Claims

1. A method for realizing ocean reverberation time domain waveform based on convolution operation, comprising: Step 1: Generate a one-dimensional random number sequence that satisfies the random process. The data volume of the random sequence is the same as the data volume of the reverberation time domain waveform to be realized; Step 2: Generate the time domain waveform of the sound source signal; Step 3: performing a convolution operation on the random number sequence and the time domain waveform of the sound source signal to obtain a stabilized time domain waveform signal with stabilized reverberation intensity; Step 4: Generate the ocean reverberation intensity attenuation curve based on the reverberation intensity theoretical model; Step 5: Using the ocean reverberation intensity attenuation curve, intensity-weight the stabilized time-domain waveform signal that has undergone the reverberation intensity stabilization process to obtain a reverberation time-domain waveform.

2. The method for realizing ocean reverberation time domain waveform based on convolution operation according to claim 1, characterized in that: The intensity weighting includes: multiplying the stabilized time domain waveform signal of the reverberation intensity stabilization process by the reverberation intensity attenuation curve in a one-to-one correspondence in time to achieve an inverse stabilization process of the reverberation signal.

3. A system for realizing ocean reverberation time domain waveform based on convolution operation, implemented based on the method according to any one of claims 1-2, characterized in that: The system comprises: A random number sequence generation module is used to generate a one-dimensional random number sequence that satisfies a random process, wherein the data volume of the random sequence is the same as the data volume of the reverberation time domain waveform to be realized; A sound source signal generating module is used to generate a time domain waveform of a sound source signal; a module for generating a stabilized time-domain waveform signal, configured to perform a convolution operation on the random number sequence and the time-domain waveform of the sound source signal to obtain a stabilized time-domain waveform signal with a stable reverberation intensity; A module for generating an ocean reverberation intensity attenuation curve is used to calculate and generate an ocean reverberation intensity attenuation curve based on a reverberation intensity theoretical model; and The reverberation time domain waveform generating module is used to perform intensity weighting on the stabilized time domain waveform signal after the reverberation intensity stabilization processing using the ocean reverberation intensity attenuation curve to obtain the reverberation time domain waveform.

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