阅读说明：本技术 一种基于坐标转换的负压波信号拐点定位方法及系统 (Negative pressure wave signal inflection point positioning method and system based on coordinate transformation ) 是由 姜涛 冼明照 李东升 于 2021-07-16 设计创作，主要内容包括：本发明涉及管道泄漏检测技术领域,具体涉及一种基于坐标转换的负压波信号拐点定位方法及系统,所述方法包括：接收传感器采集到的检测信号,根据检测信号建立信号时程曲线；若确定管道发生泄漏,则根据信号时程曲线划分得到平稳段和下降段；在平稳段选取任一点作为起始点A,在下降段选取任一点作为结束点B,分别确定起始点A和结束点B所对应的坐标；从信号时程曲线中截取起始点A和结束点B之间的曲线,作为第一曲线；将第一曲线进行旋转,得到第二曲线,确定第二曲线中每个信号点的坐标；定位第二曲线中的极值点,计算该极值点在第一曲线中所对应的时间,作为拐点出现的时间,本发明能够直接判断负压波拐点出现的时间。(The invention relates to the technical field of pipeline leakage detection, in particular to a negative pressure wave signal inflection point positioning method and system based on coordinate transformation, wherein the method comprises the following steps: receiving a detection signal acquired by a sensor, and establishing a signal time-course curve according to the detection signal; if the pipeline is determined to be leaked, dividing according to the signal time-course curve to obtain a stable section and a descending section; selecting any point as a starting point A in the stationary section, selecting any point as an end point B in the descending section, and respectively determining coordinates corresponding to the starting point A and the end point B; intercepting a curve between a starting point A and an end point B from a signal time course curve to be used as a first curve; rotating the first curve to obtain a second curve, and determining the coordinates of each signal point in the second curve; and positioning an extreme point in the second curve, and calculating the time corresponding to the extreme point in the first curve as the time when the inflection point appears.)

1. A negative pressure wave signal inflection point positioning method based on coordinate transformation is characterized by comprising the following steps:

receiving a detection signal acquired by a sensor, and establishing a signal time-course curve according to the detection signal; wherein the detection signal comprises a plurality of discrete signal points;

if the pipeline is determined to be leaked, dividing according to the signal time-course curve to obtain a stable section and a descending section;

selecting any point as a starting point A in the stable section, selecting any point as an end point B in the descending section, and respectively determining coordinates corresponding to the starting point A and the end point B;

intercepting a curve between a starting point A and an end point B from the signal time course curve to be used as a first curve;

rotating the first curve to obtain a second curve, and determining the coordinate of each signal point in the second curve;

locating an extreme point in the second curve by using an extremum solving method, wherein the extreme point is an inflection point of the original negative pressure wave signal, and calculating the time corresponding to the extreme point in the first curve as the time when the inflection point appears;

and the extreme point is a maximum value point or a minimum value point.

2. The method for positioning inflection points of negative pressure wave signals based on coordinate transformation as claimed in claim 1, wherein said receiving sensor collects detection signals, and establishes a signal time-course curve according to the detection signals, comprising:

receiving a detection signal acquired by a sensor;

determining a signal value of each signal point in the detection signal and acquisition time corresponding to the signal value;

establishing a rectangular coordinate system, and determining the coordinate of each signal point in the detection signal in the rectangular coordinate system; the abscissa of the rectangular coordinate system is time, and the ordinate of the rectangular coordinate system is a signal value;

and forming a signal time-course curve by connecting each signal point in the detection signal.

3. The method for locating the inflection point of a negative pressure wave signal based on coordinate transformation as claimed in claim 1, wherein if it is determined that a pipeline leaks, the method for locating the inflection point of the negative pressure wave signal based on coordinate transformation divides a signal time course curve into a stationary section and a descending section, and comprises the following steps:

determining a first threshold value, wherein the first threshold value is an average value of a plurality of detection signal values in a normal state of a pipeline;

sequentially selecting a section of continuous number of signal points from a signal time-course curve according to a time sequence, and dividing the signal time-course curve before a first signal point lower than a first threshold into stable sections when the signal values of the continuous number of signal points are all lower than the first threshold;

sequentially selecting a section of continuous number of signal points from the signal time-course curve according to the time sequence, and dividing the signal time-course curve after the first signal point lower than the second threshold value into descending sections when the signal values of the continuous number of signal points are all lower than the second threshold value; wherein the second threshold is less than the first threshold.

4. The method for locating an inflection point of a negative pressure wave signal based on coordinate transformation as claimed in claim 1, wherein the determining the coordinate of each signal point in the second curve comprises:

determining a coordinate value of the first signal point as a first coordinate value; wherein the first signal point is a signal point in the first curve;

calculating the first coordinate value by using a coordinate conversion formula to obtain a second coordinate value; the second coordinate value is a coordinate of a second signal point, and the second signal point is a signal point corresponding to the first signal point in the second curve.

5. The method for locating the inflection point of a negative pressure wave signal based on coordinate transformation as claimed in claim 4, wherein the coordinate transformation formula is as follows:

t_i ^′＝t_icosa+y_isina，y_i ^′＝y_icosa-t_isina；

wherein (t)_i,y_i) Is a first coordinate value of (t'_i,y'_i) And a is a rotation angle.

6. A computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, implements the steps of the coordinate transformation-based negative pressure wave signal inflection point locating method according to any one of claims 1 to 5.

7. A negative pressure wave signal inflection point positioning system based on coordinate transformation is characterized by comprising:

at least one processor;

at least one memory for storing at least one program;

when executed by the at least one processor, cause the at least one processor to implement the coordinate transformation-based negative pressure wave signal inflection point locating method of any one of claims 1 to 5.

Technical Field

The invention relates to the technical field of pipeline leakage detection, in particular to a negative pressure wave signal inflection point positioning method and system based on coordinate transformation.

Background

The pipeline is the most important conveying mode of oil and gas resources, but under the effect of factors such as third party's destruction, self ageing, corruption, the pipeline can produce the leakage inevitable, and then arouses more serious accident, has caused serious threat to the safe operation of pipeline, therefore detects the pipeline and leaks and fix a position the leakage point and has the significance.

Among various leakage detection and positioning methods, the method based on negative pressure waves has been widely paid attention to because of its advantages of simplicity, effectiveness, high reaction speed, suitability for long-distance pipelines, and the like. The time for effectively identifying the inflection point of the negative pressure wave is the key for leakage positioning by using the negative pressure wave, and has great significance for improving the leakage positioning precision. In the method for positioning the inflection point of the negative pressure wave, the inflection point of the negative pressure wave is searched by using methods such as wavelet transformation and the like through singular value detection, after singular value analysis is carried out, the occurrence time of the inflection point of the negative pressure wave is determined by judging the position where the singular value appears, and because one-time calculation is added, the error is increased, and the positioning precision of pipeline leakage is not ideal enough.

Therefore, it is desirable to provide a solution for improving the positioning accuracy of the pipeline leakage.

Disclosure of Invention

The invention aims to provide a method and a system for positioning an inflection point of a negative pressure wave signal based on coordinate transformation, which are used for solving one or more technical problems in the prior art and at least provide a beneficial selection or creation condition.

In order to achieve the purpose, the invention provides the following technical scheme:

a negative pressure wave signal inflection point positioning method based on coordinate transformation comprises the following steps:

receiving a detection signal acquired by a sensor, and establishing a signal time-course curve according to the detection signal; wherein the detection signal comprises a plurality of discrete signal points;

if the pipeline is determined to be leaked, dividing according to the signal time-course curve to obtain a stable section and a descending section;

selecting any point as a starting point A in the stable section, selecting any point as an end point B in the descending section, and respectively determining coordinates corresponding to the starting point A and the end point B;

intercepting a curve between a starting point A and an end point B from the signal time course curve to be used as a first curve;

rotating the first curve to obtain a second curve, and determining the coordinate of each signal point in the second curve;

locating an extreme point in the second curve by using an extremum solving method, wherein the extreme point is an inflection point of the original negative pressure wave signal, and calculating the time corresponding to the extreme point in the first curve as the time when the inflection point appears;

and the extreme point is a maximum value point or a minimum value point.

Further, the receiving a detection signal collected by a sensor, and establishing a signal time-course curve according to the detection signal includes:

receiving a detection signal acquired by a sensor;

determining a signal value of each signal point in the detection signal and acquisition time corresponding to the signal value;

establishing a rectangular coordinate system, and determining the coordinate of each signal point in the detection signal in the rectangular coordinate system; the abscissa of the rectangular coordinate system is time, and the ordinate of the rectangular coordinate system is a signal value;

and forming a signal time-course curve by connecting each signal point in the detection signal.

Further, if it is determined that the pipeline leaks, a stationary section and a descending section are obtained by dividing according to the signal time-course curve, and the method comprises the following steps:

determining a first threshold value, wherein the first threshold value is an average value of a plurality of detection signal values in a normal state of a pipeline;

sequentially selecting a section of continuous number of signal points from a signal time-course curve according to a time sequence, and dividing the signal time-course curve before a first signal point lower than a first threshold into stable sections when the signal values of the continuous number of signal points are all lower than the first threshold;

sequentially selecting a section of continuous number of signal points from the signal time-course curve according to the time sequence, and dividing the signal time-course curve after the first signal point lower than the second threshold value into descending sections when the signal values of the continuous number of signal points are all lower than the second threshold value; wherein the second threshold is less than the first threshold.

Further, the determining coordinates of each signal point in the second curve includes:

determining a coordinate value of the first signal point as a first coordinate value; wherein the first signal point is a signal point in the first curve;

calculating the first coordinate value by using a coordinate conversion formula to obtain a second coordinate value; the second coordinate value is a coordinate of a second signal point, and the second signal point is a signal point corresponding to the first signal point in the second curve.

Further, the coordinate transformation formula is as follows:

t′_i＝t_icosa+y_isina，y′_i＝y_icosa-t_isina；

wherein (t)_i,y_i) Is a first coordinate value of (t'_i,y'_i) And a is a rotation angle.

A computer-readable storage medium, on which a coordinate-conversion-based negative pressure wave signal inflection point locating program is stored, which, when executed by a processor, implements the steps of the coordinate-conversion-based negative pressure wave signal inflection point locating method as set forth in any one of the above.

A negative pressure wave signal inflection point positioning system based on coordinate transformation, the terminal comprises:

at least one processor;

at least one memory for storing at least one program;

when the at least one program is executed by the at least one processor, the at least one processor is enabled to implement any one of the above negative pressure wave signal inflection point location methods based on coordinate transformation.

The invention has the beneficial effects that: the invention discloses a negative pressure wave signal inflection point positioning method and system based on coordinate transformation, which can calculate the time of the inflection point of a negative pressure wave only through simple curve rotation. The invention has simple principle and high calculation precision and efficiency, and is suitable for being applied in the real-time automatic monitoring process.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without inventive exercise.

FIG. 1 is a schematic flow chart of a negative pressure wave signal inflection point locating method based on coordinate transformation in an embodiment of the present invention;

FIG. 2 is a schematic diagram of a signal time course curve according to an embodiment of the present invention;

FIG. 3 is a diagram illustrating a second curve in an embodiment of the present invention.

Detailed Description

The conception, specific structure and technical effects of the present application will be described clearly and completely with reference to the following embodiments and the accompanying drawings, so that the purpose, scheme and effects of the present application can be fully understood. It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict.

Referring to fig. 1, as shown in fig. 1, a negative pressure wave signal inflection point locating method based on coordinate transformation according to an embodiment of the present application includes the following steps:

s100, receiving a detection signal acquired by a sensor, and establishing a signal time-course curve according to the detection signal;

wherein the detection signal comprises a plurality of discrete signal points;

step S200, if the pipeline is determined to be leaked, a stable section and a descending section are obtained through division according to the signal time-course curve;

s300, selecting any point as a starting point A in the stable section, selecting any point as an end point B in the descending section, and respectively determining coordinates corresponding to the starting point A and the end point B;

in this embodiment, the coordinates corresponding to the starting point a include a time point and a signal value of the starting point a, and the coordinates corresponding to the ending point B include a time point and a signal value of the ending point B.

Step S400, intercepting a curve between a starting point A and an end point B from the signal time course curve to be used as a first curve;

s500, rotating the first curve to obtain a second curve, and determining the coordinates of each signal point in the second curve;

it can be understood that the slope of curve attenuation is different due to different leakage rates, and how to rotate the curve to obtain the highest point or the lowest point needs to be determined according to the signal falling rate; in this step, the first curve is rotated, that is, each signal point in the first curve is subjected to coordinate conversion to obtain the coordinate of each signal point in the second curve; it is understood that the inflection point in the second curve is located at the highest point or the lowest point in the coordinate system;

s600, positioning an extreme point in the second curve by using an extreme value solving method, wherein the extreme point is an inflection point of the original negative pressure wave signal, and calculating the time corresponding to the extreme point in the first curve as the time when the inflection point appears;

and the extreme point is a maximum value point or a minimum value point.

In a preferred embodiment, the detection signal comprises a pressure signal generated by a pipeline leak or a hoop strain signal of the pipe wall; the sensors are arranged at different positions of the pipeline, so that detection signals of different positions on the pipeline can be acquired;

as shown in fig. 2 and 3, according to the form of the rotated image, the maximum point of the rotated image is located by using the method of obtaining the extremum, the maximum point is the inflection point of the original negative pressure wave signal, the time of the maximum point before the image rotation is calculated, and the time is the time t when the inflection point appears_i。

It should be noted that before the negative pressure wave appears, the pressure in the pipeline or the circumferential strain signal of the pipe wall remains stable; after the negative pressure wave appears, the related signals suddenly attenuate, and for the signals, the conventional extreme value solving method cannot capture the negative pressure wave; the invention intercepts the interval which may have the negative pressure wave inflection point, and rotates the signal by adopting a coordinate conversion mode, thereby directly and rapidly determining the negative pressure wave inflection point.

In a preferred embodiment, the step S100 includes:

step S110, receiving a detection signal acquired by a sensor;

step S120, determining a signal value of each signal point in the detection signal and acquisition time corresponding to the signal value;

step S130, establishing a rectangular coordinate system, and determining the coordinate of each signal point in the detection signal in the rectangular coordinate system; the abscissa of the rectangular coordinate system is time, and the ordinate of the rectangular coordinate system is a signal value;

and step S140, forming a signal time-course curve by connecting each signal point in the detection signal.

It can be understood that the detection signal collected by the sensor is a discrete signal, and for the convenience of subsequent processing, the discrete detection signal is connected to obtain the signal time-course curve shown in fig. 2.

In a preferred embodiment, the step S200 includes:

step S210, determining a first threshold value, wherein the first threshold value is an average value of a plurality of detection signal values in a normal state of the pipeline;

specifically, a plurality of detection signal values in a normal state of the pipeline are collected before the pipeline leaks, the average value of the detection signal values is calculated, and the average value is set as a first threshold value;

step S220, sequentially selecting a section of continuous number of signal points from a signal time-course curve according to a time sequence, and dividing the signal time-course curve before a first signal point lower than a first threshold into stable sections when the signal values of the continuous number of signal points are all lower than the first threshold;

it will be appreciated that if no consecutive, certain number of detection signals is below the first threshold, the detection signal is deemed to be in a plateau; when the continuous number of detection signal values are all lower than a first threshold value, determining that the pipeline leaks;

step S230, continuously selecting a section of continuous number of signal points from the signal time-course curve according to the time sequence, and dividing the signal time-course curve after the first signal point lower than the second threshold value into descending sections when the signal values of the continuous number of signal points are all lower than the second threshold value; wherein the second threshold is less than the first threshold.

In this embodiment, the second threshold is set to a value lower than the first threshold according to the fluctuation degree of the detection signal value when the pipeline normally operates, if a certain number of continuous signals are lower than the second threshold, it is determined that a negative pressure wave occurs, and the signal lower than the second threshold is a descending section signal; it should be noted that the size of the second threshold is set according to the actual situation, generally, the smaller the second threshold is compared with the first threshold, the longer the time period of the segment to be measured is, more calculations need to be performed to determine the inflection point time, but the inflection point occurrence time can be determined more accurately; therefore, the size of the second threshold needs to be set on the premise of ensuring the accuracy of the time of occurrence of the inflection point; in one embodiment, the first threshold is set to 130.92, and correspondingly, the second threshold is set to 120; the 5000 th point is selected as a start point a in the stationary section, and the 3000 th point after the second threshold is selected as an end point B in the descending section.

In a preferred embodiment, the step S600 includes:

step S610, determining a coordinate value of the first signal point as a first coordinate value; wherein the first signal point is a signal point in the first curve;

step S620, calculating the first coordinate value by using a coordinate conversion formula to obtain a second coordinate value; the second coordinate value is a coordinate of a second signal point, and the second signal point is a signal point corresponding to the first signal point in the second curve.

In a preferred embodiment, the coordinate transformation formula is:

t′_i＝t_icosa+y_isina，y′_i＝y_icosa-t_isina；

wherein (t)_i,y_i) Is a first coordinate value of (t'_i,y'_i) And a is a rotation angle.

In one embodiment, let the signal point coordinate taken be (t)_i,y_i) The coordinate of point A is (t)_A,y_A) And the coordinate of the point B is (t)_B,y_B) (ii) a An image containing A, B interpoint curves is extracted, and then its coordinate axes are rotated by 45 ° to obtain a rotated image, as shown in fig. 3.

Corresponding to the method of fig. 1, an embodiment of the present invention further provides a computer-readable storage medium, where a coordinate-transformation-based negative pressure wave signal inflection point locating program is stored on the computer-readable storage medium, and when the coordinate-transformation-based negative pressure wave signal inflection point locating program is executed by a processor, the steps of the coordinate-transformation-based negative pressure wave signal inflection point locating method according to any of the above embodiments are implemented.

Corresponding to the method in fig. 1, an embodiment of the present invention further provides a negative pressure wave signal inflection point locating system based on coordinate transformation, where the system includes:

at least one processor;

at least one memory for storing at least one program;

when the at least one program is executed by the at least one processor, the at least one processor may implement the negative pressure wave signal inflection point locating method based on coordinate transformation according to any of the above embodiments.

The contents in the above method embodiments are all applicable to the present system embodiment, the functions specifically implemented by the present system embodiment are the same as those in the above method embodiment, and the beneficial effects achieved by the present system embodiment are also the same as those achieved by the above method embodiment.

The Processor may be a Central-Processing Unit (CPU), other general-purpose Processor, a Digital Signal Processor (DSP), an Application-Specific-Integrated-Circuit (ASIC), a Field-Programmable Gate Array (FPGA) or other Programmable logic device, a discrete Gate or transistor logic device, a discrete hardware component, or the like. The general processor can be a microprocessor or the processor can be any conventional processor and the like, the processor is a control center of the coordinate transformation based negative pressure wave signal inflection point positioning system, and various interfaces and lines are utilized to connect various parts of the whole coordinate transformation based negative pressure wave signal inflection point positioning system operable device.

The memory can be used for storing the computer program and/or the module, and the processor realizes various functions of the coordinate transformation-based negative pressure wave signal inflection point locating system by operating or executing the computer program and/or the module stored in the memory and calling the data stored in the memory. The memory may mainly include a storage program area and a storage data area, wherein the storage program area may store an operating system, an application program required by at least one function (such as a sound playing function, an image playing function, etc.), and the like; the storage data area may store data (such as audio data, a phonebook, etc.) created according to the use of the cellular phone, and the like. In addition, the memory may include high speed random access memory, and may also include non-volatile memory, such as a hard disk, a memory, a plug-in hard disk, a Smart-Media-Card (SMC), a Secure-Digital (SD) Card, a Flash-memory Card (Flash-Card), at least one magnetic disk storage device, a Flash memory device, or other volatile solid state storage device.

While the description of the present application has been made in considerable detail and with particular reference to a few illustrated embodiments, it is not intended to be limited to any such details or embodiments or any particular embodiments, but it is to be construed that the present application effectively covers the intended scope of the application by reference to the appended claims, which are interpreted in view of the broad potential of the prior art. Further, the foregoing describes the present application in terms of embodiments foreseen by the inventor for which an enabling description was available, notwithstanding that insubstantial changes from the present application, not presently foreseen, may nonetheless represent equivalents thereto.