Residual echo cancellation method and device
阅读说明：本技术 残留回声消除方法和装置 (Residual echo cancellation method and device ) 是由 耿岭 陈宇 于 2019-07-31 设计创作，主要内容包括：本公开提供一种残留回声消除方法和装置。残留回声消除装置对所采集的信号进行回声消除处理,以得到时域误差信号和时域回声估计信号,将时域误差信号和时域回声估计信号分别转换为相应的频域误差信号和频域回声估计信号,根据频域误差信号和频域回声估计信号的互相关,以及频域回声估计信号的自相关,计算泄漏系数估计值,利用频域误差信号和频域回声估计信号的幅值,以及泄漏系数估计值计算残留回声估计值,利用残留回声估计值对频域误差信号中的残留回声进行抑制,以得到频域误差抑制信号,将频域误差抑制信号转换为相应的时域输出信号。本公开在有效消除残留回声的同时,不会对有用的语音造成明显的失真,同时降低计算量。(The present disclosure provides a residual echo cancellation method and apparatus. The residual echo eliminating device carries out echo eliminating processing on the collected signals to obtain time domain error signals and time domain echo estimation signals, the time domain error signals and the time domain echo estimation signals are respectively converted into corresponding frequency domain error signals and frequency domain echo estimation signals, leakage coefficient estimation values are calculated according to cross correlation of the frequency domain error signals and the frequency domain echo estimation signals and autocorrelation of the frequency domain echo estimation signals, amplitude values of the frequency domain error signals and the frequency domain echo estimation signals and the leakage coefficient estimation values are used for calculating residual echo estimation values, residual echoes in the frequency domain error signals are restrained by the residual echo estimation values to obtain frequency domain error restraining signals, and the frequency domain error restraining signals are converted into corresponding time domain output signals. The present disclosure effectively eliminates residual echo without significant distortion of useful speech while reducing the amount of computation.)
1. A residual echo cancellation method, comprising:
carrying out echo cancellation processing on the acquired signals to obtain time domain error signals and time domain echo estimation signals;
converting the time domain error signal and the time domain echo estimation signal into a corresponding frequency domain error signal and a corresponding frequency domain echo estimation signal respectively;
calculating a leakage coefficient estimation value according to the cross correlation of the frequency domain error signal and the frequency domain echo estimation signal and the self correlation of the frequency domain echo estimation signal;
calculating a residual echo estimation value by using the frequency domain error signal, the amplitude of the frequency domain echo estimation signal and the leakage coefficient estimation value;
suppressing the residual echo in the frequency domain error signal by using the residual echo estimation value to obtain a frequency domain error suppression signal;
the frequency domain error suppression signal is converted to a corresponding time domain output signal.
2. The method of claim 1, wherein calculating a leakage coefficient estimate comprises:
calculating a first sum of cross-correlation values of the frequency-domain error signal of the l frame and the frequency-domain echo estimation signal of the l frame at each frequency point;
calculating a second sum of autocorrelation values of the frequency-domain echo estimation signal of the l frame at each frequency point;
and taking the ratio of the first sum to the second sum as a leakage coefficient estimated value corresponding to the l-th frame, wherein l is more than or equal to 1 and less than or equal to M, and M is the total frame number.
3. The method of claim 2, wherein,
and determining the cross-correlation value of the frequency domain error signal of the l frame and the frequency domain echo estimation signal of the l frame at the frequency point k by utilizing the product of the power value of the frequency domain error signal of the l frame at the frequency point k and the power value of the frequency domain echo estimation signal of the l frame at the frequency point k, and the cross-correlation value of the frequency domain error signal of the l-1 frame and the frequency domain echo estimation signal of the l-1 frame at the frequency point k.
4. The method of claim 2, wherein,
and determining the autocorrelation value of the frequency domain echo estimation signal of the frame l at the frequency point k by utilizing the square of the power value of the frequency domain echo estimation signal of the frame l at the frequency point k and the autocorrelation value of the frequency domain echo estimation signal of the frame l-1 at the frequency point k.
5. The method of claim 2, wherein computing a residual echo estimate using the leakage coefficient estimate comprises:
determining a first energy value of the frequency domain echo estimation signal of the l frame at the frequency point k by utilizing the square of the amplitude value of the frequency domain echo estimation signal of the l frame at the frequency point k, the product of the square of the amplitude value of the frequency domain echo estimation signal of the l frame and the leakage coefficient estimation value corresponding to the l frame and the energy value of the frequency domain echo estimation signal of the l-1 frame at the frequency point k;
determining a second energy value of the frequency domain error signal of the l frame at the frequency point k by utilizing the square of the amplitude value of the frequency domain error signal of the l frame at the frequency point k;
and determining a residual echo estimation value corresponding to the frequency point k of the ith frame according to the smaller energy value of the first energy value and the second energy value.
6. The method of claim 5, wherein determining the residual echo estimate corresponding to frequency point k of the l-th frame based on the smaller of the first energy value and the second energy value comprises:
and taking the product of the smaller energy value in the first energy value and the second energy value and a preset weight as a residual echo estimated value corresponding to the frequency point k of the l-th frame.
7. The method of claim 5, wherein suppressing residual echo in the frequency domain error signal using the residual echo estimate comprises:
determining a gain value corresponding to the frequency point k of the frame l by using the energy value of the frequency domain error signal of the frame l at the frequency point k and the difference value of the residual echo estimation value corresponding to the frequency point k of the frame l;
the product of the gain value corresponding to the frequency point k of the l-th frame and the value of the frequency domain error signal of the l-th frame at the frequency point k is taken as the frequency domain error suppression signal corresponding to the frequency point k of the l-th frame.
8. A residual echo cancellation device, comprising:
an echo cancellation processing module configured to perform echo cancellation processing on the acquired signal to obtain a time domain error signal and a time domain echo estimation signal;
a first processing module configured to convert the time domain error signal and the time domain echo estimation signal into a corresponding frequency domain error signal and a corresponding frequency domain echo estimation signal, respectively;
a leakage coefficient estimation module configured to calculate a leakage coefficient estimate based on a cross-correlation of the frequency domain error signal and the frequency domain echo estimate signal and an autocorrelation of the frequency domain echo estimate signal;
a residual echo estimation module configured to calculate a residual echo estimate using the frequency domain error signal and the amplitude of the frequency domain echo estimate signal, and the leakage coefficient estimate;
a residual echo suppression module configured to suppress a residual echo in the frequency domain error signal by using the residual echo estimation value to obtain a frequency domain error suppression signal;
a second processing module configured to convert the frequency domain error suppression signal into a corresponding time domain output signal.
9. A residual echo cancellation device, comprising:
a memory configured to store instructions;
a processor coupled to the memory, the processor configured to perform implementing the method of any of claims 1-7 based on instructions stored by the memory.
10. A computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions which, when executed by a processor, implement the method of any one of claims 1-7.
Technical Field
The present disclosure relates to the field of information processing, and in particular, to a residual echo cancellation method and apparatus.
Background
In the related art of processing a speech signal, adaptive filtering is generally employed. Since adaptive filtering is linear filtering, the processing effect is acceptable when the echo is small, but when the echo is large, the processed audio may generate a serious residual echo.
To process the residual echo, the following two methods are generally adopted:
1) one or more coherence measures between the received signals (including far-end signals and near-end signals) are calculated for each frequency point, a corresponding suppression factor for each frequency point is obtained, and the suppression factors are applied to the near-end signals to eliminate residual echoes in the near-end signals.
2) The linear prediction method is adopted for processing, namely, an AR (Auto Regressive) model is used for voice estimation, the difference between an original signal and an estimated value is used as an input of noise elimination, and the AR model is an autoregressive model, so that the output of the AR model is a white noise output, and further suppression can be performed in combination with other noise suppression methods.
Disclosure of Invention
The inventor finds through research that the residual echo cancellation scheme in the prior art has the following defects: 1) distortion to the useful speech signal; 2) a specific excitation signal needs to be provided, and the inverse of the Toeplitz matrix needs to be solved, which is computationally expensive.
Therefore, the present disclosure provides a scheme capable of effectively eliminating residual echo without causing significant distortion to useful speech and reducing the amount of computation.
According to a first aspect of the embodiments of the present disclosure, there is provided a residual echo cancellation method, including: carrying out echo cancellation processing on the acquired signals to obtain time domain error signals and time domain echo estimation signals; converting the time domain error signal and the time domain echo estimation signal into a corresponding frequency domain error signal and a corresponding frequency domain echo estimation signal respectively; calculating a leakage coefficient estimation value according to the cross correlation of the frequency domain error signal and the frequency domain echo estimation signal and the self correlation of the frequency domain echo estimation signal; calculating a residual echo estimation value by using the frequency domain error signal, the amplitude of the frequency domain echo estimation signal and the leakage coefficient estimation value; suppressing the residual echo in the frequency domain error signal by using the residual echo estimation value to obtain a frequency domain error suppression signal; the frequency domain error suppression signal is converted to a corresponding time domain output signal.
In some embodiments, calculating the leakage coefficient estimate comprises: calculating a first sum of cross-correlation values of the frequency-domain error signal of the l frame and the frequency-domain echo estimation signal of the l frame at each frequency point; calculating a second sum of autocorrelation values of the frequency-domain echo estimation signal of the l frame at each frequency point; and taking the ratio of the first sum to the second sum as a leakage coefficient estimated value corresponding to the l-th frame, wherein l is more than or equal to 1 and less than or equal to M, and M is the total frame number.
In some embodiments, the cross-correlation value of the frequency-domain error signal of the l frame and the frequency-domain echo estimation signal of the l frame at the frequency point k is determined by utilizing the product of the power value of the frequency-domain error signal of the l frame at the frequency point k and the power value of the frequency-domain echo estimation signal of the l frame at the frequency point k, and the cross-correlation value of the frequency-domain error signal of the l-1 frame and the frequency-domain echo estimation signal of the l-1 frame at the frequency point k.
In some embodiments, the autocorrelation value of the frequency domain echo estimation signal of the ith frame at the frequency point k is determined by using the square of the power value of the frequency domain echo estimation signal of the ith frame at the frequency point k and the autocorrelation value of the frequency domain echo estimation signal of the (l-1) th frame at the frequency point k.
In some embodiments, calculating a residual echo estimate using the leakage coefficient estimate comprises: determining a first energy value of the frequency domain echo estimation signal of the l frame at the frequency point k by utilizing the square of the amplitude value of the frequency domain echo estimation signal of the l frame at the frequency point k, the product of the square of the amplitude value of the frequency domain echo estimation signal of the l frame and the leakage coefficient estimation value corresponding to the l frame and the energy value of the frequency domain echo estimation signal of the l-1 frame at the frequency point k; determining a second energy value of the frequency domain error signal of the l frame at the frequency point k by utilizing the square of the amplitude value of the frequency domain error signal of the l frame at the frequency point k; and determining a residual echo estimation value corresponding to the frequency point k of the ith frame according to the smaller energy value of the first energy value and the second energy value.
In some embodiments, determining the residual echo estimate corresponding to frequency point k of the ith frame according to the smaller of the first energy value and the second energy value comprises: and taking the product of the smaller energy value in the first energy value and the second energy value and a preset weight as a residual echo estimated value corresponding to the frequency point k of the l-th frame.
In some embodiments, suppressing the residual echo in the frequency domain error signal using the residual echo estimate value comprises: determining a gain value corresponding to the frequency point k of the frame l by using the energy value of the frequency domain error signal of the frame l at the frequency point k and the difference value of the residual echo estimation value corresponding to the frequency point k of the frame l; the product of the gain value corresponding to the frequency point k of the l-th frame and the value of the frequency domain error signal of the l-th frame at the frequency point k is taken as the frequency domain error suppression signal corresponding to the frequency point k of the l-th frame.
According to a second aspect of the embodiments of the present disclosure, there is provided a residual echo cancellation device, including: an echo cancellation processing module configured to perform echo cancellation processing on the acquired signal to obtain a time domain error signal and a time domain echo estimation signal; a first processing module configured to convert the time domain error signal and the time domain echo estimation signal into a corresponding frequency domain error signal and a corresponding frequency domain echo estimation signal, respectively; a leakage coefficient estimation module configured to calculate a leakage coefficient estimate based on a cross-correlation of the frequency domain error signal and the frequency domain echo estimate signal and an autocorrelation of the frequency domain echo estimate signal; a residual echo estimation module configured to calculate a residual echo estimate using the frequency domain error signal and the amplitude of the frequency domain echo estimate signal, and the leakage coefficient estimate; a residual echo suppression module configured to suppress a residual echo in the frequency domain error signal by using the residual echo estimation value to obtain a frequency domain error suppression signal; a second processing module configured to convert the frequency domain error suppression signal into a corresponding time domain output signal.
According to a third aspect of the embodiments of the present disclosure, there is provided a residual echo cancellation device, including: a memory configured to store instructions; a processor coupled to the memory, the processor configured to perform a method according to any of the embodiments described above based on instructions stored in the memory.
According to a fourth aspect of the embodiments of the present disclosure, a computer-readable storage medium is provided, in which computer instructions are stored, and when executed by a processor, the computer-readable storage medium implements the method according to any of the embodiments described above.
Other features of the present disclosure and advantages thereof will become apparent from the following detailed description of exemplary embodiments thereof, which proceeds with reference to the accompanying drawings.
Drawings
In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only some embodiments of the present disclosure, and for those skilled in the art, other drawings can be obtained according to the drawings without inventive exercise.
Fig. 1 is a flowchart illustrating a residual echo cancellation method according to an embodiment of the present disclosure;
fig. 2 is a diagram illustrating a structure of a residual echo cancellation device according to an embodiment of the present disclosure;
fig. 3 is a diagram illustrating a structure of a residual echo cancellation device according to another embodiment of the present disclosure.
Detailed Description
The technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the drawings in the embodiments of the present disclosure, and it is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the disclosure, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments disclosed herein without making any creative effort, shall fall within the protection scope of the present disclosure.
The relative arrangement of the components and steps, the numerical expressions, and numerical values set forth in these embodiments do not limit the scope of the present disclosure unless specifically stated otherwise.
Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description.
Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail but are intended to be part of the specification where appropriate.
In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values.
It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.
Fig. 1 is a flowchart illustrating a residual echo cancellation method according to an embodiment of the present disclosure. In some embodiments, the residual echo cancellation method steps may be performed by a residual echo cancellation device.
In
In some embodiments, the acquired signals include a far-end signal and a near-end signal. The far-end signal is a signal played through a self-loudspeaker, such as music played by an audio device. The near-end signal is a signal collected by a microphone.
In some embodiments, the acquired signal is echo-cancelled using an adaptive filter to obtain a time-domain error signal { e }lH and a time domain echo estimation signal yl}. Wherein elTime-domain error signal for the l-th frame, ylThe signal is estimated for the time domain echo of the l-th frame. L is more than or equal to 1 and less than or equal to M, M is the total frame number
In
In some embodiments, the time-domain error signal { e } is transformed by using a fast Fourier transform FFTlH and a time domain echo estimation signal ylAre converted into corresponding frequency domain error signals { E } respectivelyl,k} and the frequency domain echo estimation signal Yl,k}. Wherein El,kIs the value of the frequency domain error signal of the l-th frame at frequency point k, Yl,kAnd estimating the value of the signal at the frequency point k for the frequency domain echo of the ith frame. K is more than or equal to 1 and less than or equal to N, and N is the number of frequency points.
In
In some embodiments, the first sum of the cross-correlation values at each frequency point of the frequency-domain error signal of the l-th frame and the frequency-domain echo estimation signal of the l-th frame is calculated, the second sum of the autocorrelation values at each frequency point of the frequency-domain echo estimation signal of the l-th frame is calculated, and the ratio of the first sum to the second sum is used as the leakage coefficient estimation value η corresponding to the l-th framelFor example, leakage coefficient estimate η is calculated by using equation (1)l。
Wherein the content of the first and second substances,the cross-correlation value of the frequency domain error signal of the l frame and the frequency domain echo estimation signal of the l frame at the frequency point k is obtained,and estimating the autocorrelation value of the signal at the frequency point k for the frequency domain echo of the ith frame.
In some embodimentsIn the method, the power value of the frequency domain error signal of the first frame at the frequency point k is utilized
For example, by calculating the cross-correlation value using equation (2)
In some embodiments, the power value of the signal at frequency point k is estimated by using the frequency domain echo of the l frame
For example, by calculating the cross-correlation value using equation (3)
In some embodiments, the power value of the frequency domain echo estimation signal at frequency point k of the I frame is calculated by using formula (4)Calculating the power value of the frequency domain error signal of the l frame at the frequency point k by using the formula (5)
The parameter γ is a smoothing factor. For example, the parameter γ is 0.85.
In some embodiments, the parameter β is described abovelAs shown in equation (6).
Parameter β0Can be adjusted as desired, e.g., β0Is 0.016.
Variance of frequency domain error signal
In
In some embodiments, the first energy value of the frequency domain echo estimation signal of the l-th frame at the frequency point k is determined by using the square of the amplitude of the frequency domain echo estimation signal of the l-th frame at the frequency point k, the product of the square of the amplitude of the frequency domain echo estimation signal of the l-th frame and the leakage coefficient estimation value corresponding to the l-th frame, and the energy value of the frequency domain echo estimation signal of the l-1 th frame at the frequency point k. And determining a second energy value of the frequency domain error signal of the ith frame at the frequency point k by utilizing the square of the amplitude value of the frequency domain error signal of the ith frame at the frequency point k. And determining the residual echo estimated value corresponding to the frequency point k of the l frame according to the smaller energy value of the first energy value and the second energy value.
For example, the first energy value of the frequency domain echo estimation signal of the l-th frame at the frequency point k is calculated by using the formula (9)
Calculating a second energy value of the frequency domain error signal of the l frame at the frequency point k by using the formula (10)
The residual echo estimate is calculated using equation (11)
Wherein the parameter a can be adjusted as required. For example, parameter a takes 0.8.
In
In some embodiments, the gain value corresponding to frequency point k of the ith frame is determined by using the energy value of the frequency domain error signal of the ith frame at frequency point k and the difference value of the residual echo estimation value corresponding to frequency point k of the ith frame. The product of the gain value corresponding to the frequency point k of the l-th frame and the value of the frequency domain error signal of the l-th frame at the frequency point k is taken as the frequency domain error suppression signal corresponding to the frequency point k of the l-th frame.
The corresponding gain value is calculated using equation (12), for example.
Wherein the parameter B can be adjusted as required. For example, the parameter B takes 1.0e-10。
Next, the residual echo in the frequency domain error signal is suppressed using equation (13).
Thereby obtaining a frequency domain error suppression signal corresponding to the frequency point k of the l-th frame
In
In some embodiments, the frequency domain error is suppressed by using an inverse Fourier transform (IFFT)Into a corresponding time domain output signal.
The resulting time domain output signal may be windowed and framed, for example, to obtain a final signal.
In the method for canceling residual echo according to the above embodiment of the present disclosure, the residual echo estimation value is calculated by using the leakage coefficient estimation value, and then the residual echo is suppressed by using the residual echo estimation value. Thereby effectively eliminating residual echo without significant distortion of useful speech and reducing computational effort.
Fig. 2 is a diagram illustrating a structure of a residual echo cancellation device according to an embodiment of the present disclosure. As shown in fig. 2, the residual echo cancellation device includes an echo
The echo
In some embodiments, the acquired signals include a far-end signal and a near-end signal. The far-end signal is a signal played through a self-loudspeaker, such as music played by an audio device. The near-end signal is a signal collected by a microphone.
In some embodiments, the acquired signal is echo-cancelled using an adaptive filter to obtain a time-domain error signal { e }lH and a time domain echo estimation signal yl}. Wherein elTime-domain error signal for the l-th frame, ylThe signal is estimated for the time domain echo of the l-th frame. L is more than or equal to 1 and less than or equal to M, M is the total frame number
The
In some embodiments, the time-domain error signal { e } is transformed by using a fast Fourier transform FFTlAnd time domain echo estimation signal{ylAre converted into corresponding frequency domain error signals { E } respectivelyl,k} and the frequency domain echo estimation signal Yl,k}. Wherein El,kIs the value of the frequency domain error signal of the l-th frame at frequency point k, Yl,kAnd estimating the value of the signal at the frequency point k for the frequency domain echo of the ith frame. K is more than or equal to 1 and less than or equal to N, and N is the number of frequency points.
The leakage
In some embodiments, the first sum of the cross-correlation values at each frequency point of the frequency-domain error signal of the l-th frame and the frequency-domain echo estimation signal of the l-th frame is calculated, the second sum of the autocorrelation values at each frequency point of the frequency-domain echo estimation signal of the l-th frame is calculated, and the ratio of the first sum to the second sum is used as the leakage coefficient estimation value η corresponding to the l-th framelFor example, leakage coefficient estimate η is calculated by using equation (1) abovel。
In some embodiments, the power value of the frequency domain error signal at frequency point k of the ith frame is utilizedThe power value of the frequency domain echo estimation signal of the ith frame at the frequency point kAnd the cross-correlation value of the frequency domain error signal of the l-1 frame and the frequency domain echo estimation signal of the l-1 frame at the frequency point k
In some embodiments, the power value of the signal at frequency point k is estimated by using the frequency domain echo of the l frame
The residual
In some embodiments, the first energy value of the frequency domain echo estimation signal of the l-th frame at the frequency point k is determined by using the square of the amplitude of the frequency domain echo estimation signal of the l-th frame at the frequency point k, the product of the square of the amplitude of the frequency domain echo estimation signal of the l-th frame and the leakage coefficient estimation value corresponding to the l-th frame, and the energy value of the frequency domain echo estimation signal of the l-1 th frame at the frequency point k. And determining a second energy value of the frequency domain error signal of the ith frame at the frequency point k by utilizing the square of the amplitude value of the frequency domain error signal of the ith frame at the frequency point k. And determining the residual echo estimated value corresponding to the frequency point k of the l frame according to the smaller energy value of the first energy value and the second energy value.
For example, the first energy value of the frequency domain echo estimation signal of the l-th frame at the frequency point k is calculated by using the above formula (9)
The residual
In some embodiments, the gain value corresponding to frequency point k of the ith frame is determined by using the energy value of the frequency domain error signal of the ith frame at frequency point k and the difference value of the residual echo estimation value corresponding to frequency point k of the ith frame. The product of the gain value corresponding to the frequency point k of the l-th frame and the value of the frequency domain error signal of the l-th frame at the frequency point k is taken as the frequency domain error suppression signal corresponding to the frequency point k of the l-th frame.
For example, the corresponding gain value is calculated using the above equation (12), and the residual echo in the frequency domain error signal is suppressed using the above equation (13).
The
In some embodiments, the frequency domain error suppression signal is converted to a corresponding time domain output signal by using an inverse fourier transform IFFT.
Fig. 3 is an exemplary block diagram of a residual echo cancellation device according to yet another embodiment of the present disclosure. As shown in fig. 3, the residual echo cancellation device comprises a memory 31 and a processor 32.
The memory 31 is used for storing instructions, the processor 32 is coupled to the memory 31, and the processor 32 is configured to execute the method according to any embodiment in fig. 1 based on the instructions stored in the memory.
As shown in fig. 3, the residual echo cancellation device further includes a communication interface 33 for information interaction with other devices. Meanwhile, the device also comprises a bus 34, and the processor 32, the communication interface 33 and the memory 31 are communicated with each other through the bus 34.
The memory 31 may comprise a high-speed RAM memory, and may further include a non-volatile memory (non-volatile memory), such as at least one disk memory. The memory 31 may also be a memory array. The storage 31 may also be partitioned and the blocks may be combined into virtual volumes according to certain rules.
Further, the processor 32 may be a central processing unit CPU, or may be an application specific integrated circuit ASIC, or one or more integrated circuits configured to implement embodiments of the present disclosure.
The present disclosure also relates to a computer-readable storage medium, wherein the computer-readable storage medium stores computer instructions, and the instructions, when executed by a processor, implement the method according to any one of the embodiments in fig. 1.
In some embodiments, the functional unit modules described above may be implemented as a general purpose Processor, a Programmable Logic Controller (PLC), a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA) or other Programmable Logic device, discrete gate or transistor Logic, discrete hardware components, or any suitable combination thereof for performing the functions described in this disclosure.
It will be understood by those skilled in the art that all or part of the steps for implementing the above embodiments may be implemented by hardware, or may be implemented by a program instructing relevant hardware, where the program may be stored in a computer-readable storage medium, and the above-mentioned storage medium may be a read-only memory, a magnetic disk or an optical disk, etc.
The description of the present disclosure has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to practitioners skilled in this art. The embodiment was chosen and described in order to best explain the principles of the disclosure and the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated.