CN104864274B - Pipe leakage acoustic signals Enhancement Method - Google Patents

Pipe leakage acoustic signals Enhancement Method Download PDF

Info

Publication number
CN104864274B
CN104864274B CN201510275111.8A CN201510275111A CN104864274B CN 104864274 B CN104864274 B CN 104864274B CN 201510275111 A CN201510275111 A CN 201510275111A CN 104864274 B CN104864274 B CN 104864274B
Authority
CN
China
Prior art keywords
acoustic signals
pipe leakage
frame
points
enhancement method
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
CN201510275111.8A
Other languages
Chinese (zh)
Other versions
CN104864274A (en
Inventor
林伟国
何昭岩
吴海燕
王奋伟
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
PLA 63960 ARMY
Beijing University of Chemical Technology
Original Assignee
PLA 63960 ARMY
Beijing University of Chemical Technology
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by PLA 63960 ARMY, Beijing University of Chemical Technology filed Critical PLA 63960 ARMY
Priority to CN201510275111.8A priority Critical patent/CN104864274B/en
Publication of CN104864274A publication Critical patent/CN104864274A/en
Application granted granted Critical
Publication of CN104864274B publication Critical patent/CN104864274B/en
Expired - Fee Related legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Landscapes

  • Examining Or Testing Airtightness (AREA)

Abstract

The invention discloses a kind of pipe leakage acoustic signals Enhancement Method.This method comprises the following steps:The pipeline inside acoustic signals obtained by dynamic pressure transmitter are sampled, the pending acoustic signals of a frame that length is M points are obtained;Acoustic signals pending to a frame carry out low-pass filtering treatment, eliminate frequency and are higher than fcHigh-frequency Interference acoustic signals;According to formulaEnhancing processing is carried out to acoustic signals after denoising, the enhanced acoustic signals of a frame are obtained.It can compensate for the integral term of the reflecting wave signal LF-response characteristic lacked in the output of dynamic pressure transmitter, has stabilization, significant enhancing effect to pipe leakage acoustic signals, improves the signal to noise ratio of pipe leakage acoustic signals.And when carrying out signal enhancing processing, parameter selection is simple, amount of calculation is small, the real-time that whole processing method is implemented is very strong.

Description

Pipe leakage acoustic signals Enhancement Method
Technical field
Believe the present invention relates to the signal transacting in Discussion on Pipe Leakage Detection Technology field, more particularly to a kind of pipe leakage sound wave Number Enhancement Method.
Background technology
Pipeline transportation is the major way of fossil energy and harmful influence conveying, due to pipeline aging, corrosion failure and punching The reasons such as stolen, pipe leakage happens occasionally, and causes resources loss, environmental pollution even casualties.Therefore, pipe leakage is examined Survey technology is developed so far, and is still one of the hot issue of domestic and foreign scholars research.In existing negative pressure wave method, sonic method, matter In the pipelines leakage detection methods such as amount/volumetric balance method, distribution type fiber-optic method, because sonic sensor frequency response is wide, The features such as sensitivity is high, correlation function peak is sharp, is letting out of most being approved at present in terms of Sensitivity of leak test and positioning precision Leak detection method.The speed that the sensitvity constraint of sonic method pipeline leakage testing occurs in the size of slip and leakage, signal Enhancing is necessary technological means in leak detection practice.But traditional Wavelet Denoising Method and EMD decompose (Empirical Mode Decomposition, empirical mode decomposition) method can not all realize the signal enhancing of active to be difficult to ensure that stable signal Enhancing effect.Wavelet Denoising Method is a kind of signal enhancing method of non-self-adapting, and the different wavelet basis of selection or filter scale may Antipodal signal enhancing effect can be obtained;And EMD methods do not only exist the problem of boundary effect is difficult to effectively overcome, and The problem of also solving which IMF component reconstruction signal of selection.In fact, due to metallic conduit and its pumped (conveying) medium have it is low The frequency domain distribution of its frequency domain distribution and pipeline internal interference signals base when frequency filtering characteristic, leakage signal travel to first and last station This is overlapping, and the active ingredient of leakage signal can also certainly will incur loss while noise is suppressed, and is leaked and small for slow Leakage is even more so.Therefore, a kind of stable acoustic signals active Enhancement Method of enhancing effect is explored to be significant.
The content of the invention
Based on this, it is necessary to which providing a kind of can effectively strengthen the pipe leakage acoustic signals Enhancement Method of acoustic signals.
To realize a kind of pipe leakage acoustic signals Enhancement Method that the object of the invention is provided, comprise the following steps:
The pipeline inside acoustic signals obtained by dynamic pressure transmitter are sampled, it is the one of M points to obtain length The pending acoustic signals of frame;
Acoustic signals pending to a frame carry out low-pass filtering treatment, eliminate frequency and are higher than fcInterference sound wave letter Number, obtain acoustic signals after denoising;
Enhancing processing is carried out to acoustic signals after the removal noise according to below equation, the enhanced sound wave of a frame is obtained Signal:
Wherein, y (t) is acoustic signals after denoising,For y (t) integral term, KsFor low frequency gain factors (Ks>=1), fy (t) is enhanced acoustic signals.
As a kind of embodiment of pipe leakage acoustic signals Enhancement Method, the M=2N, wherein N are positive integer, The pending acoustic signals of one frame include N point historical datas and N point real time datas, the last point of the N points historical data On the historical data time before first real time data of the N points real time data, and the last point historical data with First real time data is two continuous sampled points.
As a kind of embodiment of pipe leakage acoustic signals Enhancement Method, using the N point real time datas as working as The N point historical datas of the pending acoustic signals of next frame of the pending acoustic signals of previous frame.
As a kind of embodiment of pipe leakage acoustic signals Enhancement Method, the dynamic pressure transmitter includes suitable The sonic sensor of secondary connection, charge amplifier, preferably also include voltage order one amplifying circuit, low pass filter, two grades of electricity Press amplifying circuit and V/I converter units;
And the sonic sensor insertion type is arranged on and carried out on the pipeline of leak detection, it is adaptable to inside sense pipeline Sound wave change.
As a kind of embodiment of pipe leakage acoustic signals Enhancement Method, methods described passes through remote-terminal unit Acoustic signals carry out A/D conversions with preset sample frequency inside the pipeline obtained to the dynamic pressure transmitter.
As a kind of embodiment of pipe leakage acoustic signals Enhancement Method, step is to the pending sound wave of a frame Signal carries out low-pass filtering treatment, eliminates the interference acoustic signals that frequency is higher than fc;Beneficial effects of the present invention include:The present invention The pipe leakage acoustic signals Enhancement Method of offer, it can compensate for the reflecting wave letter lacked in the output of dynamic pressure transmitter Pipe leakage acoustic signals are had stabilization, significant enhancing effect by the integral term of number LF-response characteristic, and to pipeline inside just Normal acoustic signals have no influence, improve the signal to noise ratio of pipe leakage acoustic signals.Entered using the acoustic signals after present invention processing Row pipe leakage judges, can effectively reduce the rate of false alarm and rate of failing to report in leak detection.And when carrying out signal enhancing processing, ginseng Number selection is simple, amount of calculation is small, and the real-time that whole processing method is implemented is very strong.
Brief description of the drawings
Fig. 1 is a kind of flow chart of a specific embodiment of pipe leakage acoustic signals Enhancement Method of the invention;
Fig. 2 is dynamic pressure general in an a kind of specific embodiment of pipe leakage acoustic signals Enhancement Method of the invention Signal flow diagram in transmitter;
Fig. 3 for a kind of pipe leakage acoustic signals Enhancement Method of the invention a concrete application example in contain pipe leakage One frame original figure acoustic signals of acoustic signals;
Acoustic signals of the Fig. 4 for the original figure acoustic signals in Fig. 3 after LPF;
Fig. 5 be Fig. 4 in acoustic signals by pipe leakage acoustic signals Enhancement Method processing after obtain it is enhanced Pipe leakage acoustic signals.
Embodiment
In order to make the purpose , technical scheme and advantage of the present invention be clearer, below in conjunction with accompanying drawing to the present invention's The embodiment of pipe leakage acoustic signals Enhancement Method is illustrated.It should be appreciated that specific implementation described herein Example is not intended to limit the present invention only to explain the present invention.
The pipe leakage acoustic signals Enhancement Method of one embodiment of the invention, as shown in figure 1, comprising the following steps:
The pipeline inside acoustic signals obtained by dynamic pressure transmitter are sampled, obtain length for M points by S100 The pending acoustic signals of a frame.
Wherein, can be by sequentially electric for obtaining and transmitting the dynamic pressure transmitter of acoustic signals inside detected pipeline The sonic sensor of connection, charge amplifier, preferably also include voltage order one amplifying circuit, low pass filter, secondary voltage Amplifying circuit and V/I converter units composition.Wherein, as shown in Fig. 2 charge amplifier is used as pipe leakage acoustic signals transport part The pre-amplifier unit divided, voltage order one amplifying circuit, low pass filter and secondary voltage amplifying circuit collectively form pipeline and let out The signal condition unit of acoustic signals hop is leaked, the V/I converter units constitute the signal transmitting of dynamic pressure transmitter Unit.Sonic sensor is arranged on using insertion type mounting means by mounting hole inside the pipeline for implementing leak detection, and is felt The change of acoustic signals inside test tube road.Specifically, sonic sensor can use piezoelectric pressure indicator, pass through mounting hole On pipeline, and sensor end face is set to be in contact with the medium in tested pipeline, so as to obtain inside institute's detection pipeline Acoustic signals.Electric charge amplification and voltage order one amplifying circuit of the acoustic signals by charge amplifier are amplified into low pass filtered Ripple device carries out preliminary noise filtering, and acoustic signals carry out signal amplification by secondary voltage amplifying circuit again afterwards, again finally The acoustic signals of voltage form are converted into 4-20mA current signal transfer to remote-terminal unit by V/I converter units (RTU, Remote Terminal Unit).Current signal herein is used as acoustic signals inside foregoing pipeline.Current signal In remote-terminal unit after sampling resistor, then by A/D converting units with preset sample frequency sampling obtain sound wave believe Number data signal.Data signal by network interface can be uploaded to prison after microprocessor AT91SAM9261 ARM processing Store and handle in control computer.Certainly can also be had using other the microprocessors of similar functions to data signal at Reason.It will be understood by those skilled in the art that the pipe leakage acoustic signals Enhancement Method of the embodiment of the present invention is obtained except step S100 Take outside the pipe leakage acoustic signals of digital form, other the step of all can monitoring computer or other have computing function Carried out in processor.
Herein it should be noted that the pipeline inside acoustic signals in the embodiment of the present invention refer in detected pipeline All acoustic signals, rather than refer in particular to pipeline and occur leakage moment, or certain sound wave that leakage is had occurred and that comprising pipeline Signal.After being handled by the method for the embodiment of the present invention acoustic signals inside detected pipeline, after processing Data can more accurately determine whether detected pipeline is leaked.
And for sample frequency, can be determined according to the ability of the follow-up processor for carrying out data processing.For higher position reason The processor of ability can be sampled using higher sample frequency to analog signal.
S200, acoustic signals pending to a frame carry out low-pass filtering treatment, eliminate frequency and are higher than fcBack drop Ripple signal, obtains acoustic signals after denoising.In this step, the pending acoustic signals of a frame first can be passed through into cut-off frequency For fcLowpass digital filter to eliminate High-frequency Interference, more preferably, LPF can be replaced by the way of Wavelet Denoising Method Device carries out low-pass filtering treatment.
Acoustic signals after the removal noise are carried out enhancing processing according to formula (1), obtain enhanced sound wave by S300 Signal:
Wherein, y (t) is acoustic signals after denoising,For y (t) integral term, KsFor low frequency gain factors (Ks>=1), fy (t) is enhanced acoustic signals.
Specifically, trapezoidal integration, rectangular integration can be used by carrying out numerical integration according to formula (1) in actual calculating process And cubic spline difference product grading mode.It is illustrated herein with trapezoidal integration formula.Carried out using trapezoidal integration formula When numerical integration is calculated, shown in calculating process such as formula (2).
Wherein, y (k) is the pending acoustic signals of kth point in the pending acoustic signals of a frame, and the 1st point of y (1) is pending Acoustic signals, Sy (k) is the integral term to y (k), fsFor sample frequency, TcFor the time constant of charge amplifier, m increases for low frequency Beneficial coefficient (m >=1), x (k) is acoustic signals inside the enhanced pipeline of kth point.
The pipe leakage acoustic signals Enhancement Method of the embodiment of the present invention, it can compensate in the output of dynamic pressure transmitter Pipe leakage acoustic signals are had stabilization, significant enhancing effect by the integral term of the reflecting wave signal LF-response characteristic of missing Really, to ambient noise and have no significant effect, improve the signal to noise ratio of pipe leakage acoustic signals.And from formula (1) and formula (2) as can be seen that when carrying out signal enhancing processing, parameter selection is simple, amount of calculation is small, the real-time of whole processing method implementation is made Property is very strong.It is follow-up that pipe leakage judgement is carried out according to enhanced signal, it can effectively reduce the rate of false alarm in leak detection And rate of failing to report.
Wherein, for the composition of a frame pending data, in one of the embodiments, M is even number.M=2N, N is just Integer.N points are N point historical datas before in the pending acoustic signals of a frame of M points, and rear N points are N point real time datas.The N points are gone through On the last point historical data time of history data before first real time data of the N points real time data, and it is described most Latter point historical data is two continuous sampled points with first real time data., equally can root for N specific value Determined according to specific computational accuracy and the disposal ability of processor.Such as sample frequency fsM may be selected in=50Hz situation 6000, and N is 3000, i.e., the sampled data every time to 6000 points is handled.
One frame pending data is divided into after historical data and real time data, the N points in the pending data of present frame are real When data can as next frame pending data N point historical datas so that two frame processing datas have certain connection, It ensure that the integrality of abnormal signal.And adopt this method to shorten and constitute the pending of the new enough points of a frame The time of signal.Accelerate the speed of data processing, while also just improving the efficiency of pipeline leakage testing.
It should be noted that in actual pipeline leakage testing, sound wave sensing is placed simultaneously in the initial station of pipeline and terminal During device, the acoustic signals that can be obtained respectively to the sonic sensor of initial station and terminal carry out leakage signal using the method for the present invention Enhancing is handled, and carries out the diagnosis of further pipe leakage and the determination of leak position using the signal after enhancing processing.
Below with an instantiation illustrate the present invention pipe leakage acoustic signals Enhancement Method processing procedure and its The effect of signal enhancing.
As shown in figure 3, being one section of original figure acoustic signals (totally 6000 signals) containing pipe leakage acoustic signals. The sampling precision of signal is 12, and sample frequency is 50Hz.Signal after db9 Wavelet Denoising Methods (wavelet decomposition scales are 3) As shown in Figure 4.Then time domain trapezoidal integration signal enhancing (this is carried out to the filtered signal application formula (2) shown in Fig. 4 again The gain coefficient m=50 of time-domain integration in example) afterwards signal it is as shown in Figure 5.From figure 5 it can be seen that at the 2000th point and Pipe leakage acoustic signals between 3000 points have obtained obvious enhancing.It is computed drawing:Pipeline before strengthening as shown in Figure 2 The signal to noise ratio for leaking acoustic signals is 2.8dB, and the signal to noise ratio of enhanced pipe leakage acoustic signals as shown in Figure 5 is 9.7dB, signal to noise ratio enhances 6.9dB.Signal enhancing effect is obvious.
It will be understood by those skilled in the art that to solve the problem of invention is proposed, data processing section can be with computer Based on program handling process, the computer program worked out by above-mentioned flow is performed by computer, pipe leakage sound wave is believed Number carry out signal enhancing processing.And realize all or part of flow in above-described embodiment method can by computer program come Related hardware is instructed to complete, described program can be stored in a computer read/write memory medium, the program is being performed When, it may include such as the flow of the embodiment of above-mentioned each method.Wherein, described storage medium can be magnetic disc, CD, read-only storage Memory body (Read-Only Memory, ROM) or random access memory (Random Access Memory, RAM) etc..
Embodiment described above only expresses the several embodiments of the present invention, and it describes more specific and detailed, but simultaneously Therefore the limitation to the scope of the claims of the present invention can not be interpreted as.It should be pointed out that for one of ordinary skill in the art For, without departing from the inventive concept of the premise, various modifications and improvements can be made, these belong to the guarantor of the present invention Protect scope.Therefore, the protection domain of patent of the present invention should be determined by the appended claims.

Claims (5)

1. a kind of pipe leakage acoustic signals Enhancement Method, it is characterised in that comprise the following steps:
The pipeline inside acoustic signals obtained by dynamic pressure transmitter are sampled, the frame that length is M points is obtained and treats Handle acoustic signals;
Acoustic signals pending to a frame carry out low-pass filtering treatment, eliminate frequency and are higher than fcInterference acoustic signals, obtain Acoustic signals after denoising;
Enhancing processing is carried out to acoustic signals after the denoising according to below equation, the enhanced acoustic signals of a frame are obtained:
Wherein, y (t) is acoustic signals after denoising,For y (t) integral term, KsFor low frequency gain factors, Ks≥ 1, fy (t) is enhanced acoustic signals.
2. pipe leakage acoustic signals Enhancement Method according to claim 1, it is characterised in that M=2N, wherein N is just Integer, the pending acoustic signals of a frame include N point historical datas and N point real time datas, the N points historical data it is last On some historical data time before first real time data of the N points real time data, and N points historical data is most First real time data of latter point historical data and the N points real time data is two continuous sampled points.
3. pipe leakage acoustic signals Enhancement Method according to claim 2, it is characterised in that count the N points in real time According to the N point historical datas of the pending acoustic signals of next frame as the pending acoustic signals of present frame.
4. the pipe leakage acoustic signals Enhancement Method according to any one of claims 1 to 3, it is characterised in that described dynamic State pressure transmitter include be sequentially connected with sonic sensor, charge amplifier, voltage order one amplifying circuit, low pass filter, Secondary voltage amplifying circuit and V/I converter units;
And the sonic sensor insertion type is arranged on and carried out on the pipeline of leak detection, it is adaptable to the sound inside sense pipeline Ripple changes.
5. pipe leakage acoustic signals Enhancement Method according to claim 4, it is characterised in that methods described passes through long-range Acoustic signals carry out A/D conversions with preset sample frequency inside the pipeline that terminal unit is obtained to the dynamic pressure transmitter.
CN201510275111.8A 2015-05-26 2015-05-26 Pipe leakage acoustic signals Enhancement Method Expired - Fee Related CN104864274B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201510275111.8A CN104864274B (en) 2015-05-26 2015-05-26 Pipe leakage acoustic signals Enhancement Method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201510275111.8A CN104864274B (en) 2015-05-26 2015-05-26 Pipe leakage acoustic signals Enhancement Method

Publications (2)

Publication Number Publication Date
CN104864274A CN104864274A (en) 2015-08-26
CN104864274B true CN104864274B (en) 2017-08-04

Family

ID=53910304

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201510275111.8A Expired - Fee Related CN104864274B (en) 2015-05-26 2015-05-26 Pipe leakage acoustic signals Enhancement Method

Country Status (1)

Country Link
CN (1) CN104864274B (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106594526B (en) * 2016-12-02 2019-04-12 上海环宇消防集团有限公司 A kind of water supply network state monitoring method and device based on hydraulic pressure sampled data
CN106989282B (en) * 2017-05-16 2020-03-20 北京化工大学 Virtual sound wave detection method and system for pipeline leakage
CN109088611A (en) * 2018-09-28 2018-12-25 咪付(广西)网络技术有限公司 A kind of auto gain control method and device of acoustic communication system
CN110131595B (en) * 2019-05-21 2020-09-04 北京化工大学 Method, device and system for processing pipeline slow leakage signal
CN112600473B (en) * 2020-11-23 2023-06-30 江苏科技大学 Permanent magnet synchronous motor rotor position estimation system and method
CN114576568B (en) * 2022-02-25 2023-08-29 辽宁石油化工大学 Pipeline leakage detection method and device based on infrasonic wave

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1755342A (en) * 2004-09-28 2006-04-05 北京埃德尔黛威新技术有限公司 Method and apparatus for detecting leakage of liquid pressure pipeline
CN101464171A (en) * 2007-12-18 2009-06-24 深圳职业技术学院 Ultrasonic flux detection system and detection method
CN101871834A (en) * 2010-04-23 2010-10-27 北京中科通视科技有限公司 Wireless remote water leakage detection device and system
CN102095391A (en) * 2010-12-03 2011-06-15 华中科技大学 Duct length measuring device based on sound waves
CN103775833A (en) * 2014-01-09 2014-05-07 中国石油天然气股份有限公司 Pipeline leakage monitoring system and method

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3688400B2 (en) * 1996-08-23 2005-08-24 東京瓦斯株式会社 Signal processing method in piping leak location identification method

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1755342A (en) * 2004-09-28 2006-04-05 北京埃德尔黛威新技术有限公司 Method and apparatus for detecting leakage of liquid pressure pipeline
CN101464171A (en) * 2007-12-18 2009-06-24 深圳职业技术学院 Ultrasonic flux detection system and detection method
CN101871834A (en) * 2010-04-23 2010-10-27 北京中科通视科技有限公司 Wireless remote water leakage detection device and system
CN102095391A (en) * 2010-12-03 2011-06-15 华中科技大学 Duct length measuring device based on sound waves
CN103775833A (en) * 2014-01-09 2014-05-07 中国石油天然气股份有限公司 Pipeline leakage monitoring system and method

Also Published As

Publication number Publication date
CN104864274A (en) 2015-08-26

Similar Documents

Publication Publication Date Title
CN104864274B (en) Pipe leakage acoustic signals Enhancement Method
CN100456010C (en) Method for detecting leakage of oil gas pipe based on pressure signal knee
CN107328528B (en) Ultrasonic air tightness detection system and method based on multiple sensors
CN106352243A (en) Gas transmission pipeline leakage detection system based on acoustic method
CN106523928B (en) Pipeline leakage detection method based on the screening of sound wave real time data two level
CN101246467B (en) Leakage locating method combining self-adapting threshold value leak detection and multi-dimension fast delay time search
CN108050396A (en) A kind of fluid line source of leaks monitoring and positioning system and method
CN104764564B (en) Valves leakage detection method based on sonic sensor
CN113008361B (en) Method and device for detecting noise of substation boundary of transformer substation against environmental interference
CN111695465B (en) Pipe network fault diagnosis and positioning method and system based on pressure wave mode identification
CN102032447A (en) System for monitoring urban gas pipeline in real time and using method thereof
CN105092691A (en) Quantitative detection method and detector for detecting accumulated oxide scales in pipelines
CN102537668B (en) Method for determining ground mark time of inner detector of pipeline
CN202580647U (en) Online leakage detection and positioning system for heating pipeline
CN108181377A (en) A kind of PCCP steel wires fracture of wire intelligent interpretation system and method
CN115949891B (en) Intelligent control system and control method for LNG (liquefied Natural gas) station
CN110285332B (en) Natural gas pipeline safety monitoring method based on acoustic pulse compression
CN116973448A (en) Guided wave pipeline defect guided wave circumferential positioning system and method
CN204085486U (en) A kind of corrosive pipeline monitoring device based on array piezoelectric film sensor
CN114576568B (en) Pipeline leakage detection method and device based on infrasonic wave
CN103363880B (en) Pipeline girth weld joint identification and positioning method
CN108119764A (en) Time reversal adaptive mesh gas pipeline leak hunting method
CN115076619A (en) Gas pipeline ball valve internal leakage detection system based on acoustic emission technology
CN117153194B (en) Real-time water leakage monitoring method of water leakage detection valve
CN110553156B (en) Pipeline ultrasonic guided wave compression sensing health monitoring method

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
EXSB Decision made by sipo to initiate substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant
CF01 Termination of patent right due to non-payment of annual fee

Granted publication date: 20170804