阅读说明：本技术 一种频域下光纤检测管道泄漏与位置的算法 (The algorithm of fiber laser arrays pipe leakage and position under a kind of frequency domain ) 是由 左健存 张洋 朱贤训 赵之阳 于 2019-08-05 设计创作，主要内容包括：本发明公开了一种频域下光纤检测管道泄漏与位置的算法；本发明采用光纤监测管道状态,在频域下结合信号增强算法处理光纤监测信号,最终获得重构信号,从而判断管道状态及泄漏位置。本发明显著提高了管道泄漏位置信号的特征,根据处理后的信号的特点,设定合适的报警阈值即可精确判断管道是否发生泄漏以及泄漏位置,检测精度高,误报率低,实用性强且具有较好的信噪比。(The invention discloses the algorithms of fiber laser arrays pipe leakage and position under a kind of frequency domain；The present invention uses fiber-optic monitoring pipeline conditions, and binding signal enhances algorithm process fiber-optic monitoring signal under frequency domain, reconstruction signal is finally obtained, to judge pipeline conditions and leak position.Invention significantly improves the features of pipe leakage position signal, the characteristics of according to treated signal, setting suitable alarm threshold value can accurately judge whether pipeline occurs leakage and leak position, and detection accuracy is high, rate of false alarm is low, it is practical and have preferable signal-to-noise ratio.)

1. the algorithm of fiber laser arrays pipe leakage and position under a kind of frequency domain, which is characterized in that the method includes the steps of:

Step 1: pretreatment

Signal characteristic when according to pipe leakage pre-processes the N point signal on each meter of optical fiber:

Wherein, x [n] is monitoring signals, and e is the truth of a matter of natural logrithm, and i is imaginary unit, and N is signal length, 0≤n < N；

Step 2: being further processed frequency-region signal

By frequency-region signalIt is decomposed according to formula (2) and formula (3):

c_{J, k}=∑_nc_{J-1, n}h_n-2kK=(0,1,2 ..., N-1) (2)

d_{J, k}=∑_nc_{J-1, n}g_n-2kK=(0,1,2 ..., N-1) (3)

Wherein, c_{J, k}For coefficient, d_{J, k}For coefficient, h (e^jw)=g (e^j(w-π)), j is Decomposition order；

By formula (4) threshold value:

Wherein, N is signal length；

D is handled according to formula (5)_{J, k}, obtain coefficient w_{J, k}, i.e.,

Frequency-region signal after being reconstructed according to formula (6):

c_{J-1, n}=∑_nc_{J, n}h_n-2k+∑_nw_{J, n}g_n-2k (6)

Step 3: frequency on each meter of sensor fibre is done in the signal amplitude of 20-5000Hz it is cumulative, to obtain sensor fibre The distribution curve of position and cumulative signal can determine whether raw pipe according to the signal strength size of distribution curve and position Whether road occurs leakage and leak position.

Technical field

The present invention relates to optical fiber sensing monitoring technical field, under specifically a kind of frequency domain fiber laser arrays pipe leakage with The algorithm of position

Background technique

OTDR technique is relied primarily on to the processing method of the Fibre Optical Sensor signal of pipe leakage position at present, in OTDR technique On the basis of the positioning to leakage point position realized by power spectrumanalysis method, when equal method, time-domain analysis etc. based on frequency domain. By the variation that can cause to survey pipe stress wave power spectrum signal when pipeline internal leakage, the change of this signal of analysis can be passed through Change to detect leak position, it is many due to influencing the factor that pipe stress wave is propagated, it is difficult to describe pipe Vibration with the method for parsing It is dynamic.When by pipe leakage vibration signal do based on frequency domain when processing judgement leakage generation, in answering for Practical Project It is larger with middle limitation, and there is stronger noise signal to cause leakage feature is unobvious, positioning accuracy is low, rate of false alarm is high to ask Topic,

Summary of the invention

For current fiber laser arrays pipe leakage position transducing signal processing method the problem of, the present invention propose The algorithm of fiber laser arrays pipe leakage and position under a kind of frequency domain；It uses fiber-optic monitoring pipeline conditions, combines under frequency domain Signal enhancement algorithm handles fiber-optic monitoring signal, final to obtain reconstruction signal and provide suitable threshold value accordingly, to judge to manage Road state and leak position.Invention significantly improves the features of pipe leakage position signal, and detection accuracy is high, rate of false alarm It is low, it is practical and have preferable signal-to-noise ratio.

The algorithm of fiber laser arrays pipe leakage and position under a kind of frequency domain, the method includes the steps of:

Step 1: pretreatment

Signal characteristic when according to pipe leakage pre-processes the N point signal on each meter of optical fiber:

Wherein, x [n] is monitoring signals, and e is the truth of a matter of natural logrithm, and i is imaginary unit, and N is signal length, 0≤n < N；Step 2: being further processed frequency-region signal

By frequency-region signalIt is decomposed according to formula (2) and formula (3):

c_{J, k}=∑_nc_{J-1, n}h_n-2kK=(0,1,2 ..., N-1) (2)

d_{J, k}=∑_nc_{J-1, n}g_n-2kK=(0,1,2 ..., N-1) (3)

Wherein, c_{J, k}For coefficient, d_{J, k}For coefficient, h (e^jw)=g (e^j(w-π)), j is Decomposition order；

Soft-threshold is determined by formula (4):

Wherein, N is signal length；

D is handled according to formula (5)_{J, k}, obtain coefficient w_j, k, i.e.,

Frequency-region signal after being reconstructed according to formula (6):

c_{J-1, n}=∑_nc_{J, n}h_n-2k+∑_nw_{J, n}g_n-2k (6)

Step 3: frequency on each meter of sensor fibre is done in the signal amplitude of 20-5000Hz it is cumulative, to be sensed The distribution curve of fiber position and cumulative signal can determine whether according to the signal strength size of distribution curve and position Whether raw pipeline occurs leakage and leak position.

Compared to the prior art, the present invention is used to detect easy to operate with the method for leakage position whether pipe leakage, and Detection accuracy is high, and rate of false alarm is low, practical, and has preferable signal-to-noise ratio.

Detailed description of the invention

The transducing signal exemplary diagram of Fig. 1 is that treated in embodiment 1 fiber laser arrays pipe leakage and position.

Specific embodiment

Present invention will be further explained below with reference to the attached drawings and examples, but protection model of the invention should not be limited with this It encloses.