CN108985277B - Method and system for filtering background noise in power signal - Google Patents

Method and system for filtering background noise in power signal Download PDF

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CN108985277B
CN108985277B CN201810970724.7A CN201810970724A CN108985277B CN 108985277 B CN108985277 B CN 108985277B CN 201810970724 A CN201810970724 A CN 201810970724A CN 108985277 B CN108985277 B CN 108985277B
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翟明岳
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Guangdong University of Petrochemical Technology
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Abstract

The invention discloses a method and a system for filtering background noise in a power signal. The filtering method comprises the following steps: acquiring a measured power signal parameter; dividing the actually measured power sequence to determine a plurality of subsequences; calculating a mean of autocorrelation functions of a plurality of the subsequences; determining the impulse response of the superposition filter according to the mean value; filtering the subsequence according to the impulse response, and determining a filtered subsequence; rearranging the filtered subsequences to determine a filtered power signal sequence. The filtering method and the system provided by the invention can effectively filter the background noise in the continuously generated strong pulse power signal.

Description

一种功率信号中背景噪声滤除方法及系统A method and system for filtering background noise in a power signal

技术领域technical field

本发明涉及背景噪声滤除领域，特别是涉及一种功率信号中背景噪声滤除方法及系统。The present invention relates to the field of background noise filtering, in particular to a method and system for filtering background noise in a power signal.

背景技术Background technique

负载开关事件检测是能量分解中最为重要的一步，既要检测到事件发生，同时还能确定事件发生的时刻，但是开关事件检测的精度受功率信号(功率序列)中噪声的影响较大，尤其是功率信号中普遍存在着脉冲噪声，进一步影响了检测精度；在负载开关事件检测过程中，对功率信号进行滤波是很重要的一步，常用的消除背景噪声的方法是低通滤波器和中值滤波器对功率信号滤波。Load switching event detection is the most important step in energy decomposition. It is necessary to detect the occurrence of the event and to determine the moment when the event occurs. However, the accuracy of switching event detection is greatly affected by the noise in the power signal (power sequence), especially It is the impulse noise that generally exists in the power signal, which further affects the detection accuracy; in the process of load switching event detection, filtering the power signal is a very important step. The commonly used methods to eliminate background noise are low-pass filter and median The filter filters the power signal.

尽管低通滤波器可以有效地滤除背景噪声，并能在一定程度上保持信号的突变性；但是，鉴于信号突变点(功率发生跳变的地方)对于确定开关事件的重要性，希望滤波器不要改变功率信号的突变性，但是低通滤波器往往做不到这一点，低通滤波器会使得突变点不再陡峭，变得光滑，使得突变时间(对应于开关事件的发生时间)难以确定。Although a low-pass filter can effectively filter out background noise and preserve the abruptness of the signal to a certain extent; however, given the importance of the signal abrupt point (where the power jump occurs) in determining switching events, it is desirable that the filter Don't change the abruptness of the power signal, but this is often not possible with low-pass filters, which make the transition point less steep and smooth, making the transition time (corresponding to when the switching event occurs) difficult to determine .

中值滤波器虽然在保持信号突变性以及滤除脉冲噪声方面表现突出，但是对于连续发生的强脉冲功率信号中的背景噪声(白噪声)，滤波效果欠佳。Although the median filter is outstanding in maintaining the abruptness of the signal and filtering out the impulse noise, the filtering effect is not good for the background noise (white noise) in the continuous strong impulse power signal.

发明内容SUMMARY OF THE INVENTION

本发明的目的是提供一种功率信号中背景噪声滤除方法及系统，以解决连续发生的强脉冲功率信号中的背景噪声滤除效果欠佳的问题。The purpose of the present invention is to provide a method and system for filtering background noise in a power signal, so as to solve the problem of poor filtering effect of background noise in a continuously occurring strong pulse power signal.

为实现上述目的，本发明提供了如下方案：For achieving the above object, the present invention provides following scheme:

一种功率信号中背景噪声滤除方法，包括：A method for filtering background noise in a power signal, comprising:

获取实测功率信号参数；所述实测功率信号参数包括实测功率信号序列以及实测功率信号序列长度N；所述实测功率信号序列包括多个实测功率信号，所述实测功率信号为含有噪声的功率信号，N为所述实测功率信号的序号，N≥1；Acquiring measured power signal parameters; the measured power signal parameters include a measured power signal sequence and a measured power signal sequence length N; the measured power signal sequence includes a plurality of measured power signals, and the measured power signals are power signals containing noise, N is the sequence number of the measured power signal, N≥1;

对所述实测功率序列进行划分，确定多个子序列；所述子序列的长度为L，

Figure BDA0001776121660000021
The measured power sequence is divided to determine a plurality of subsequences; the length of the subsequence is L,
Figure BDA0001776121660000021

计算多个所述子序列的自相关函数的均值；calculating the mean value of the autocorrelation functions of a plurality of the subsequences;

根据所述均值确定叠加滤波器的脉冲响应；determining the impulse response of the superposition filter according to the mean;

根据所述脉冲响应，对所述子序列进行滤波，确定滤波后的子序列；filtering the subsequence according to the impulse response to determine the filtered subsequence;

将所述滤波后的子序列重新排列，确定滤波后的功率信号序列。The filtered subsequences are rearranged to determine a filtered power signal sequence.

可选的，所述对所述实测功率序列进行划分，确定多个子序列，具体包括：Optionally, dividing the measured power sequence to determine multiple subsequences, specifically including:

按照所述实测功率序列的先后次序进行划分，确定多个子序列。The measured power sequence is divided according to the order of sequence, and a plurality of subsequences are determined.

可选的，所述按照所述实测功率序列的先后次序进行划分，确定多个子序列之后，还包括：Optionally, after the division is performed according to the order of the measured power sequence, and after multiple subsequences are determined, the method further includes:

判断所述实测功率序列是否存在剩余功率信号，得到第一判断结果；Judging whether there is a residual power signal in the measured power sequence, and obtaining a first judgment result;

若所述第一判断结果表示为所述实测功率序列存在剩余功率信号，将所述剩余功率信号内最后一个功率信号扩充为长度为L的剩余序列，并将所述剩余序列作为所述实测功率序列的子序列。If the first judgment result indicates that there is a residual power signal in the measured power sequence, expand the last power signal in the residual power signal into a residual sequence of length L, and use the residual sequence as the measured power A subsequence of a sequence.

可选的，所述计算多个所述子序列的自相关函数的均值，具体包括：Optionally, the calculating the mean value of the autocorrelation functions of the plurality of subsequences specifically includes:

根据公式

Figure BDA0001776121660000022
计算多个所述子序列的自相关函数的均值；其中，
Figure BDA0001776121660000023
τ为自相关函数的自变量，在计算自相关函数值时，子序列xi的时间延迟；
Figure BDA0001776121660000024
τ＝-L+1,…,0,…,L-1。According to the formula
Figure BDA0001776121660000022
Calculate the mean of the autocorrelation functions of a plurality of the subsequences; wherein,
Figure BDA0001776121660000023
τ is the independent variable of the autocorrelation function, when calculating the value of the autocorrelation function, the time delay of the subsequence x i ;
Figure BDA0001776121660000024
τ=-L+1,...,0,...,L-1.

可选的，所述根据所述均值确定叠加滤波器的脉冲响应，具体包括：Optionally, the determining the impulse response of the superposition filter according to the mean value specifically includes:

根据公式

Figure BDA0001776121660000025
确定叠加滤波器的脉冲响应；其中，
Figure BDA0001776121660000026
d为时间窗的长度，
Figure BDA0001776121660000027
ωd[τ]是叠加滤波器脉冲响应的时间窗。According to the formula
Figure BDA0001776121660000025
Determines the impulse response of the superposition filter; where,
Figure BDA0001776121660000026
d is the length of the time window,
Figure BDA0001776121660000027
ω d [τ] is the time window of the impulse response of the stack filter.

一种功率信号中背景噪声滤除系统，包括：A background noise filtering system in a power signal, comprising:

实测功率信号参数获取模块，用于获取实测功率信号参数；所述实测功率信号参数包括实测功率信号序列以及实测功率信号序列长度N；所述实测功率信号序列包括多个实测功率信号，所述实测功率信号为含有噪声的功率信号，N为所述实测功率信号的序号，N≥1；The measured power signal parameter acquisition module is used to obtain the measured power signal parameters; the measured power signal parameters include the measured power signal sequence and the measured power signal sequence length N; the measured power signal sequence includes a plurality of measured power signals, the measured power signal The power signal is a power signal containing noise, N is the serial number of the measured power signal, and N≥1;

子序列确定模块，用于对所述实测功率序列进行划分，确定多个子序列；所述子序列的长度为L，

Figure BDA0001776121660000031
A subsequence determination module, configured to divide the measured power sequence to determine a plurality of subsequences; the length of the subsequence is L,
Figure BDA0001776121660000031

均值计算模块，用于计算多个所述子序列的自相关函数的均值；a mean value calculation module, used for calculating the mean value of the autocorrelation functions of a plurality of the subsequences;

脉冲响应确定模块，用于根据所述均值确定叠加滤波器的脉冲响应；an impulse response determination module, configured to determine the impulse response of the superposition filter according to the mean value;

滤波模块，用于根据所述脉冲响应，对所述子序列进行滤波，确定滤波后的子序列；a filtering module, configured to filter the subsequence according to the impulse response, and determine the filtered subsequence;

滤波后的功率信号序列确定模块，用于将所述滤波后的子序列重新排列，确定滤波后的功率信号序列。The filtered power signal sequence determination module is configured to rearrange the filtered subsequences to determine the filtered power signal sequence.

可选的，所述子序列确定模块具体包括：Optionally, the subsequence determination module specifically includes:

子序列确定单元，用于按照所述实测功率序列的先后次序进行划分，确定多个子序列。A subsequence determination unit, configured to divide the measured power sequence according to the sequence of the measured power sequence, and determine a plurality of subsequences.

可选的，还包括：Optionally, also include:

第一判断单元，用于判断所述实测功率序列是否存在剩余功率信号，得到第一判断结果；a first judging unit, configured to judge whether there is a residual power signal in the measured power sequence, and obtain a first judgment result;

子序列扩充单元，用于若所述第一判断结果表示为所述实测功率序列存在剩余功率信号，将所述剩余功率信号内最后一个功率信号扩充为长度为L的剩余序列，并将所述剩余序列作为所述实测功率序列的子序列。A subsequence expansion unit, configured to expand the last power signal in the residual power signal into a residual sequence of length L if the first judgment result indicates that there is a residual power signal in the measured power sequence, and add the residual power signal to the residual sequence. The remaining sequence is used as a subsequence of the measured power sequence.

可选的，所述均值计算模块具体包括：Optionally, the mean value calculation module specifically includes:

均值计算单元，用于根据公式

Figure BDA0001776121660000032
计算多个所述子序列的自相关函数的均值；其中，
Figure BDA0001776121660000033
τ为自相关函数的自变量，在计算自相关函数值时，子序列xi的时间延迟；
Figure BDA0001776121660000041
τ＝-L+1,…,0,…,L-1。Mean calculation unit, used to calculate according to the formula
Figure BDA0001776121660000032
Calculate the mean of the autocorrelation functions of a plurality of the subsequences; wherein,
Figure BDA0001776121660000033
τ is the independent variable of the autocorrelation function, when calculating the value of the autocorrelation function, the time delay of the subsequence x i ;
Figure BDA0001776121660000041
τ=-L+1,...,0,...,L-1.

可选的，所述脉冲响应确定模块具体包括：Optionally, the impulse response determination module specifically includes:

脉冲响应确定单元，用于根据公式

Figure BDA0001776121660000042
确定叠加滤波器的脉冲响应；其中，
Figure BDA0001776121660000043
d为时间窗的长度，
Figure BDA0001776121660000044
Figure BDA0001776121660000045
ωd[τ]是叠加滤波器脉冲响应的时间窗。Impulse response determination unit for
Figure BDA0001776121660000042
Determines the impulse response of the superposition filter; where,
Figure BDA0001776121660000043
d is the length of the time window,
Figure BDA0001776121660000044
Figure BDA0001776121660000045
ω d [τ] is the time window of the impulse response of the stack filter.

根据本发明提供的具体实施例，本发明公开了以下技术效果：本发明提供了一种功率信号中背景噪声滤除方法及系统，通过对实测功率序列进行划分，确定多个子序列，并对每个子序列进行滤波，确定滤波后的子序列，再将对滤波后的子序列重新排列，能够有效滤除连续发生的强脉冲功率信号中的背景噪声。According to the specific embodiments provided by the present invention, the present invention discloses the following technical effects: the present invention provides a method and system for filtering background noise in a power signal. Filter the subsequences, determine the filtered subsequences, and then rearrange the filtered subsequences, which can effectively filter out the background noise in the continuously occurring strong pulse power signal.

附图说明Description of drawings

为了更清楚地说明本发明实施例或现有技术中的技术方案，下面将对实施例中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动性的前提下，还可以根据这些附图获得其他的附图。In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings required in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some of the present invention. In the embodiments, for those of ordinary skill in the art, other drawings can also be obtained according to these drawings without creative labor.

图1为本发明所提供的功率信号中背景噪声滤除方法流程图；1 is a flowchart of a method for filtering background noise in a power signal provided by the present invention;

图2为本发明所提供的子序列划分示意图；2 is a schematic diagram of subsequence division provided by the present invention;

图3为本发明所提供的功率信号中背景噪声滤除系统结构图。FIG. 3 is a structural diagram of a system for filtering background noise in a power signal provided by the present invention.

具体实施方式Detailed ways

下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其他实施例，都属于本发明保护的范围。The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

本发明的目的是提供一种功率信号中背景噪声滤除方法及系统，能够有效滤除连续发生的强脉冲功率信号中的背景噪声。The purpose of the present invention is to provide a method and system for filtering background noise in a power signal, which can effectively filter out the background noise in a continuously occurring strong pulse power signal.

为使本发明的上述目的、特征和优点能够更加明显易懂，下面结合附图和具体实施方式对本发明作进一步详细的说明。In order to make the above objects, features and advantages of the present invention more clearly understood, the present invention will be described in further detail below with reference to the accompanying drawings and specific embodiments.

图1为本发明所提供的功率信号中背景噪声滤除方法流程图，如图1所示，一种功率信号中背景噪声滤除方法，包括：FIG. 1 is a flowchart of a method for filtering background noise in a power signal provided by the present invention. As shown in FIG. 1 , a method for filtering background noise in a power signal includes:

步骤101：获取实测功率信号参数；所述实测功率信号参数包括实测功率信号序列以及实测功率信号序列长度N；所述实测功率信号序列包括多个实测功率信号，所述实测功率信号为含有噪声的功率信号，N为所述实测功率信号的序号，N≥1。Step 101: Obtain the measured power signal parameters; the measured power signal parameters include a measured power signal sequence and a measured power signal sequence length N; the measured power signal sequence includes a plurality of measured power signals, and the measured power signals are noise-containing. Power signal, N is the serial number of the measured power signal, N≥1.

输入实测的功率信号序列P1,P2,…,PN,N为功率信号序列的长度。Input the measured power signal sequence P 1 , P 2 , . . . , P N , where N is the length of the power signal sequence.

步骤102：对所述实测功率序列进行划分，确定多个子序列；所述子序列的长度为L，

Figure BDA0001776121660000051
Step 102: Divide the measured power sequence to determine a plurality of subsequences; the length of the subsequence is L,
Figure BDA0001776121660000051

图2为本发明所提供的子序列划分示意图，如图2所示，选取长度为L的时间窗，

Figure BDA0001776121660000052
符号
Figure BDA0001776121660000053
表示下取整，同时将功率信号序列按照先后次序划分为10个子序列，每个子序列的长度为L，相邻子序列中的数据不重复。除了这10个子序列之外，有可能还有一些功率数据未被划进这10个子序列，并且这些剩余数据的个数小于L。以最后一个数据的值扩充为L个长度的子序列，作为最后一个子序列(第11个子序列)。Fig. 2 is a schematic diagram of subsequence division provided by the present invention, as shown in Fig. 2, a time window of length L is selected,
Figure BDA0001776121660000052
symbol
Figure BDA0001776121660000053
Represents rounding down, and at the same time, the power signal sequence is divided into 10 subsequences according to the sequence, the length of each subsequence is L, and the data in adjacent subsequences are not repeated. In addition to the 10 subsequences, there may be some power data not included in the 10 subsequences, and the number of these remaining data is less than L. The value of the last data is expanded into a subsequence of length L as the last subsequence (the 11th subsequence).

步骤103：计算多个所述子序列的自相关函数的均值。Step 103: Calculate the mean value of the autocorrelation functions of a plurality of the subsequences.

将多个子序列xi重新表示为：Re-express multiple subsequences x i as:

x1＝[P1,P2,…,PL]x 1 =[P 1 ,P 2 ,...,P L ]

x2＝[PL+1,PL+2,…,PL+L]x 2 =[ PL+1 , PL+2 ,..., PL+L ]

xi＝[P(i-1)*L+1,P(i-1)*L+2,…,P(i-1)*L+L],i＝1,2,…,11x i =[P (i-1)*L+1 ,P (i-1)*L+2 ,...,P (i-1)*L+L ],i=1,2,...,11

根据公式

Figure BDA0001776121660000054
计算多个所述子序列的自相关函数的均值；其中，
Figure BDA0001776121660000055
τ为自相关函数的自变量，在计算自相关函数值时，子序列xi的时间延迟；
Figure BDA0001776121660000061
τ＝-L+1,…,0,…,L-1。According to the formula
Figure BDA0001776121660000054
Calculate the mean of the autocorrelation functions of a plurality of the subsequences; wherein,
Figure BDA0001776121660000055
τ is the independent variable of the autocorrelation function, when calculating the value of the autocorrelation function, the time delay of the subsequence x i ;
Figure BDA0001776121660000061
τ=-L+1,...,0,...,L-1.

步骤104：根据所述均值确定叠加滤波器的脉冲响应。Step 104: Determine the impulse response of the superposition filter according to the mean value.

叠加滤波器的脉冲响应f(τ)为：

Figure BDA0001776121660000062
其中，
Figure BDA0001776121660000063
d为时间窗的长度，决定了滤波器长度，一般
Figure BDA0001776121660000064
ωd[τ]是叠加滤波器脉冲响应的一项，为一种特殊的时间窗；由于这一个时间窗，使得叠加滤波器的脉冲响应为有限脉冲响应滤波器，便于计算。The impulse response f(τ) of the superposition filter is:
Figure BDA0001776121660000062
in,
Figure BDA0001776121660000063
d is the length of the time window, which determines the length of the filter, generally
Figure BDA0001776121660000064
ω d [τ] is an item of the impulse response of the superposition filter, which is a special time window; because of this time window, the impulse response of the superposition filter is a finite impulse response filter, which is easy to calculate.

步骤105：根据所述脉冲响应，对所述子序列进行滤波，确定滤波后的子序列。Step 105: Filter the subsequence according to the impulse response to determine the filtered subsequence.

根据公式

Figure BDA0001776121660000065
i＝1,2,…,11对每一个子序列进行滤波，其中，运算*表示卷积；
Figure BDA0001776121660000066
为实测数据子序列xi(l)的估计，
Figure BDA0001776121660000067
为滤除了背景噪声的功率信号。According to the formula
Figure BDA0001776121660000065
i=1,2,...,11 filter each subsequence, where operation * represents convolution;
Figure BDA0001776121660000066
is the estimation of the measured data subsequence x i (l),
Figure BDA0001776121660000067
is the power signal with background noise filtered out.

步骤106：将所述滤波后的子序列重新排列，确定滤波后的功率信号序列。Step 106: Rearrange the filtered subsequences to determine a filtered power signal sequence.

将子序列重新组合，得到滤波后的功率信号序列

Figure BDA0001776121660000068
Figure BDA0001776121660000069
Recombine the subsequences to get the filtered power signal sequence
Figure BDA0001776121660000068
Figure BDA0001776121660000069

由于第11个序列有可能是通过扩充第N个数据值得到的，所以只需从序列

Figure BDA00017761216600000610
中选取前面的N个数据即可。Since it is possible that the 11th sequence was obtained by augmenting the Nth data value, it is only necessary to start from the sequence
Figure BDA00017761216600000610
You can select the first N data from the .

图3为本发明所提供的功率信号中背景噪声滤除系统结构图，如图3所示，一种功率信号中背景噪声滤除系统，包括：FIG. 3 is a structural diagram of a background noise filtering system in a power signal provided by the present invention. As shown in FIG. 3, a background noise filtering system in a power signal includes:

实测功率信号参数获取模块301，用于获取实测功率信号参数；所述实测功率信号参数包括实测功率信号序列以及实测功率信号序列长度N；所述实测功率信号序列包括多个实测功率信号，所述实测功率信号为含有噪声的功率信号，N为所述实测功率信号的序号，N≥1。The measured power signal parameter acquisition module 301 is used to obtain measured power signal parameters; the measured power signal parameters include a measured power signal sequence and a measured power signal sequence length N; the measured power signal sequence includes a plurality of measured power signals, the The measured power signal is a power signal containing noise, N is the serial number of the measured power signal, and N≥1.

子序列确定模块302，用于对所述实测功率序列进行划分，确定多个子序列；所述子序列的长度为L，

Figure BDA0001776121660000071
A subsequence determination module 302, configured to divide the measured power sequence to determine a plurality of subsequences; the length of the subsequence is L,
Figure BDA0001776121660000071

所述子序列确定模块302具体包括：The subsequence determination module 302 specifically includes:

子序列确定单元，用于按照所述实测功率序列的先后次序进行划分，确定多个子序列。A subsequence determination unit, configured to divide the measured power sequence according to the sequence of the measured power sequence, and determine a plurality of subsequences.

第一判断单元，用于判断所述实测功率序列是否存在剩余功率信号，得到第一判断结果；a first judging unit, configured to judge whether there is a residual power signal in the measured power sequence, and obtain a first judgment result;

子序列扩充单元，用于若所述第一判断结果表示为所述实测功率序列存在剩余功率信号，将所述剩余功率信号内最后一个功率信号扩充为长度为L的剩余序列，并将所述剩余序列作为所述实测功率序列的子序列。A subsequence expansion unit, configured to expand the last power signal in the residual power signal into a residual sequence of length L if the first judgment result indicates that there is a residual power signal in the measured power sequence, and add the residual power signal to the residual sequence. The remaining sequence is used as a subsequence of the measured power sequence.

均值计算模块303，用于计算多个所述子序列的自相关函数的均值。The mean value calculation module 303 is configured to calculate the mean value of the autocorrelation functions of the plurality of subsequences.

所述均值计算模块303具体包括：The mean value calculation module 303 specifically includes:

均值计算单元，用于根据公式

Figure BDA0001776121660000072
计算多个所述子序列的自相关函数的均值；其中，
Figure BDA0001776121660000073
τ为自相关函数的自变量，在计算自相关函数值时，子序列xi的时间延迟；
Figure BDA0001776121660000074
τ＝-L+1,…,0,…,L-1。Mean calculation unit, used to calculate according to the formula
Figure BDA0001776121660000072
Calculate the mean of the autocorrelation functions of a plurality of the subsequences; wherein,
Figure BDA0001776121660000073
τ is the independent variable of the autocorrelation function, when calculating the value of the autocorrelation function, the time delay of the subsequence x i ;
Figure BDA0001776121660000074
τ=-L+1,...,0,...,L-1.

脉冲响应确定模块304，用于根据所述均值确定叠加滤波器的脉冲响应。The impulse response determination module 304 is configured to determine the impulse response of the superposition filter according to the mean value.

所述脉冲响应确定模块304具体包括：The impulse response determination module 304 specifically includes:

脉冲响应确定单元，用于根据公式

Figure BDA0001776121660000075
确定叠加滤波器的脉冲响应；其中，
Figure BDA0001776121660000076
d为时间窗的长度，
Figure BDA0001776121660000077
Figure BDA0001776121660000078
ωd[τ]是叠加滤波器脉冲响应的时间窗。Impulse response determination unit for
Figure BDA0001776121660000075
Determines the impulse response of the superposition filter; where,
Figure BDA0001776121660000076
d is the length of the time window,
Figure BDA0001776121660000077
Figure BDA0001776121660000078
ω d [τ] is the time window of the impulse response of the stack filter.

滤波模块305，用于根据所述脉冲响应，对所述子序列进行滤波，确定滤波后的子序列。The filtering module 305 is configured to filter the subsequence according to the impulse response, and determine the filtered subsequence.

滤波后的功率信号序列确定模块306，用于将所述滤波后的子序列重新排列，确定滤波后的功率信号序列。The filtered power signal sequence determination module 306 is configured to rearrange the filtered subsequences to determine the filtered power signal sequence.

采用本发明所提供的滤除方法及系统在实际应用中为一种叠加滤波器，主要滤除背景噪声中的白噪声，该叠加滤波器带通滤波器，比单纯的低通滤波器相比具有更高的截止频率，使得信号突变点的高频特性得以更好地保留，从而可以得到比低通滤波器更好的滤波效果，计算速度更快。In practical application, the filtering method and system provided by the present invention is a superposition filter, which mainly filters out white noise in the background noise. Compared with the simple low-pass filter, the superposition filter band-pass filter With a higher cutoff frequency, the high-frequency characteristics of the signal mutation point can be better preserved, so that a better filtering effect can be obtained than a low-pass filter, and the calculation speed is faster.

本说明书中各个实施例采用递进的方式描述，每个实施例重点说明的都是与其他实施例的不同之处，各个实施例之间相同相似部分互相参见即可。对于实施例公开的系统而言，由于其与实施例公开的方法相对应，所以描述的比较简单，相关之处参见方法部分说明即可。The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same and similar parts between the various embodiments can be referred to each other. For the system disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant part can be referred to the description of the method.

本文中应用了具体个例对本发明的原理及实施方式进行了阐述，以上实施例的说明只是用于帮助理解本发明的方法及其核心思想；同时，对于本领域的一般技术人员，依据本发明的思想，在具体实施方式及应用范围上均会有改变之处。综上所述，本说明书内容不应理解为对本发明的限制。In this paper, specific examples are used to illustrate the principles and implementations of the present invention. The descriptions of the above embodiments are only used to help understand the methods and core ideas of the present invention; meanwhile, for those skilled in the art, according to the present invention There will be changes in the specific implementation and application scope. In conclusion, the contents of this specification should not be construed as limiting the present invention.

Claims (8)

1. A method for filtering background noise from a power signal, comprising:
acquiring a measured power signal parameter; the actually measured power signal parameters comprise an actually measured power signal sequence and an actually measured power signal sequence length N; the actually measured power signal sequence comprises a plurality of actually measured power signals, the actually measured power signals are power signals containing noise, N is a serial number of the actually measured power signals, and N is more than or equal to 1;
dividing the actually measured power sequence to determine a plurality of subsequences; the length of the sub-sequence is L,
Figure FDA0002564311420000011
calculating a mean of autocorrelation functions of a plurality of the subsequences;
determining the impulse response of the superposition filter according to the mean value; the determining the impulse response of the superposition filter according to the mean value specifically includes: according to the formula
Figure FDA0002564311420000012
Determining an impulse response of a superposition filter; wherein,
Figure FDA0002564311420000013
d is the length of the time window,
Figure FDA0002564311420000014
ωd[τ]is the time window of the superposition filter impulse response; r isi[τ]A mean of autocorrelation functions for a plurality of said subsequences; τ is an argument of the autocorrelation function, τ -L +1, …,0, …, L-1;
filtering the subsequence according to the impulse response, and determining a filtered subsequence;
rearranging the filtered subsequences to determine a filtered power signal sequence.
2. The background noise filtering method according to claim 1, wherein the dividing the measured power sequence to determine a plurality of subsequences specifically comprises:
and dividing according to the sequence of the actually measured power sequence to determine a plurality of subsequences.
3. The background noise filtering method according to claim 2, wherein the dividing according to the sequence of the measured power sequence and after determining the plurality of subsequences further comprises:
judging whether the actually measured power sequence has a residual power signal or not to obtain a first judgment result;
and if the first judgment result indicates that the actually measured power sequence has a residual power signal, expanding the last power signal in the residual power signal into a residual sequence with the length of L, and taking the residual sequence as a subsequence of the actually measured power sequence.
4. The method of claim 1, wherein the calculating a mean of the autocorrelation functions of the plurality of subsequences specifically comprises:
according to the formula
Figure FDA0002564311420000021
Calculating a mean of autocorrelation functions of a plurality of the subsequences; wherein,
Figure FDA0002564311420000022
τ being an argument of the autocorrelation function, i.e. the subsequence x when calculating the autocorrelation function valueiA time delay of (d);
Figure FDA0002564311420000023
5. a system for filtering background noise from a power signal, comprising:
the actual measurement power signal parameter acquisition module is used for acquiring actual measurement power signal parameters; the actually measured power signal parameters comprise an actually measured power signal sequence and an actually measured power signal sequence length N; the actually measured power signal sequence comprises a plurality of actually measured power signals, the actually measured power signals are power signals containing noise, N is a serial number of the actually measured power signals, and N is more than or equal to 1;
a subsequence determining module for dividing the actually measured power sequence and determiningA plurality of subsequences; the length of the sub-sequence is L,
Figure FDA0002564311420000024
the mean value calculation module is used for calculating the mean value of the autocorrelation functions of the subsequences;
the impulse response determining module is used for determining the impulse response of the superposition filter according to the mean value; the impulse response determining module specifically includes: an impulse response determination unit for determining the impulse response according to the formula
Figure FDA0002564311420000025
Determining an impulse response of a superposition filter; wherein,
Figure FDA0002564311420000026
d is the length of the time window,
Figure FDA0002564311420000027
Figure FDA0002564311420000028
ωd[τ]is the time window of the superposition filter impulse response; r isi[τ]A mean of autocorrelation functions for a plurality of said subsequences; τ is an argument of the autocorrelation function, τ -L +1, …,0, …, L-1;
the filtering module is used for filtering the subsequence according to the impulse response and determining a filtered subsequence;
and a filtered power signal sequence determining module, configured to rearrange the filtered subsequences, and determine a filtered power signal sequence.
6. The background noise filtering system of claim 5, wherein the subsequence determining module specifically comprises:
and the subsequence determining unit is used for dividing according to the sequence of the actually measured power sequence and determining a plurality of subsequences.
7. The background noise filtering system according to claim 6, further comprising:
the first judging unit is used for judging whether the actually measured power sequence has a residual power signal or not to obtain a first judging result;
and the subsequence expansion unit is used for expanding the last power signal in the residual power signal into a residual sequence with the length of L and taking the residual sequence as the subsequence of the actual measurement power sequence if the first judgment result indicates that the actual measurement power sequence has residual power signals.
8. The background noise filtering system according to claim 5, wherein the mean calculating module specifically includes:
a mean value calculation unit for calculating a mean value according to a formula
Figure FDA0002564311420000031
Calculating a mean of autocorrelation functions of a plurality of the subsequences; wherein,
Figure FDA0002564311420000032
τ being an argument of the autocorrelation function, i.e. the subsequence x when calculating the autocorrelation function valueiA time delay of (d);
Figure FDA0002564311420000033
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