CN116380140A - Distributed acoustic wave sensing system based on mean value filtering technology and measuring method thereof - Google Patents
Distributed acoustic wave sensing system based on mean value filtering technology and measuring method thereof Download PDFInfo
- Publication number
- CN116380140A CN116380140A CN202310664909.6A CN202310664909A CN116380140A CN 116380140 A CN116380140 A CN 116380140A CN 202310664909 A CN202310664909 A CN 202310664909A CN 116380140 A CN116380140 A CN 116380140A
- Authority
- CN
- China
- Prior art keywords
- original
- pixel
- demodulation information
- pixel points
- acoustic wave
- 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.)
- Granted
Links
- 238000001914 filtration Methods 0.000 title claims abstract description 50
- 238000000034 method Methods 0.000 title claims abstract description 30
- 239000013307 optical fiber Substances 0.000 claims abstract description 54
- 238000005259 measurement Methods 0.000 claims abstract description 18
- 238000012545 processing Methods 0.000 claims abstract description 14
- 239000011159 matrix material Substances 0.000 claims description 24
- 239000000835 fiber Substances 0.000 claims description 16
- 238000000691 measurement method Methods 0.000 claims description 12
- 230000008030 elimination Effects 0.000 claims 1
- 238000003379 elimination reaction Methods 0.000 claims 1
- 238000001514 detection method Methods 0.000 abstract description 2
- 238000010586 diagram Methods 0.000 description 11
- 239000000919 ceramic Substances 0.000 description 7
- 230000000694 effects Effects 0.000 description 5
- 230000007613 environmental effect Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 230000010287 polarization Effects 0.000 description 2
- 238000004088 simulation Methods 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- 229910052691 Erbium Inorganic materials 0.000 description 1
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/35338—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre using other arrangements than interferometer arrangements
- G01D5/35354—Sensor working in reflection
- G01D5/35358—Sensor working in reflection using backscattering to detect the measured quantity
- G01D5/35361—Sensor working in reflection using backscattering to detect the measured quantity using elastic backscattering to detect the measured quantity, e.g. using Rayleigh backscattering
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
- G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
- G01D5/26—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light
- G01D5/32—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light
- G01D5/34—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells
- G01D5/353—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable characterised by optical transfer means, i.e. using infrared, visible, or ultraviolet light with attenuation or whole or partial obturation of beams of light the beams of light being detected by photocells influencing the transmission properties of an optical fibre
- G01D5/3537—Optical fibre sensor using a particular arrangement of the optical fibre itself
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
- Y02D30/00—Reducing energy consumption in communication networks
- Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measurement Of Mechanical Vibrations Or Ultrasonic Waves (AREA)
Abstract
The embodiment of the application provides a distributed acoustic wave sensing system based on a mean value filtering technology and a measuring method thereof, which relate to the technical field of distributed optical fiber sensing detection and comprise the following steps: collecting backward Rayleigh scattering signals generated by vibration signals along the sensing optical fiber within a preset time period; demodulating the collected backward Rayleigh scattering signals to obtain first demodulation information, wherein the first demodulation information comprises demodulation information of each position along the sensing optical fiber; constructing an original image according to the first demodulation information, wherein the original image comprises images formed by the first demodulation information of all positions along the sensing optical fiber in the preset time period; performing mean filtering processing on the original image to obtain a target image; reconstructing second demodulation information according to the target image, wherein the second demodulation information comprises demodulation information after noise information is eliminated at each position along the sensing optical fiber, so that measurement accuracy is improved.
Description
Technical Field
The application relates to the technical field of distributed optical fiber sensing detection, in particular to a distributed acoustic wave sensing system based on a mean value filtering technology and a measuring method thereof.
Background
The principle of the distributed acoustic wave sensing technology is to obtain the change of the physical quantity (such as sound, vibration and the like) required to be detected by detecting the phase change of the backward Rayleigh scattered light along the sensing optical fiber. The distributed acoustic wave sensing system has the advantages of light weight, small volume, high sensitivity, strong electromagnetic interference resistance and the like, and has extremely high application value in the fields of perimeter security, oil and gas exploration, pipeline monitoring and the like.
In the related art, in the measurement process of the distributed acoustic wave sensing system, incident light interferes with backward Rayleigh scattered light at a certain point along the sensing optical fiber, and the change of physical quantities such as acoustic wave or vibration of the point can cause the phase change of the backward Rayleigh scattered light and generate backward Rayleigh scattered signals, so that demodulation information of the change quantity of acoustic wave or vibration of the point can be obtained by demodulating the backward Rayleigh scattered signals, and the demodulation information is a measurement result. Because the sensing optical fibers are continuously distributed in the space, the distributed acoustic wave sensing system can quantitatively detect the change of the physical quantity of any point in the space, thereby realizing distributed sensing.
However, in the measurement process of the distributed acoustic wave sensing system, the backward rayleigh scattering signal is affected by random noise fluctuation such as laser phase noise, polarization noise, environmental noise and the like, and when the backward rayleigh scattering signal at each position along the transmission line of the sensing fiber is demodulated, the obtained demodulation information contains noise information generated by a plurality of random noise fluctuation, so that the demodulation information is interfered by the noise information, and measurement errors are brought.
Disclosure of Invention
The embodiment of the application provides a distributed acoustic wave sensing system based on a mean value filtering technology and a measuring method thereof, so as to solve the technical problem of measuring errors of the existing distributed acoustic wave sensing system.
In a first aspect, an embodiment of the present application provides a distributed acoustic wave sensing measurement method based on a mean filtering technique, including:
collecting backward Rayleigh scattering signals generated by vibration signals along the sensing optical fiber within a preset time period;
demodulating the collected backward Rayleigh scattering signals to obtain first demodulation information, wherein the first demodulation information comprises demodulation information of each position along the sensing optical fiber;
constructing an original image according to the first demodulation information, wherein the original image comprises images formed by sensing the first demodulation information of all positions of the optical fiber along the line in a preset time period;
performing mean filtering processing on the original image to obtain a target image;
and reconstructing second demodulation information according to the target image, wherein the second demodulation information comprises demodulation information after noise information is eliminated at each position along the sensing optical fiber.
In one possible implementation, the average filtering processing of the original image to obtain the target image includes:
acquiring first pixel values of all original pixel points in an original image, wherein the first pixel values comprise pixel values of adjacent pixel points of the original pixel points, the adjacent pixel points are pixel points surrounding the original pixel points, and the number of the adjacent pixel points is at least one;
acquiring a second pixel value of each original pixel point of the original image, wherein the second pixel value is the pixel value of the original pixel point;
generating a pixel average value of each original pixel point in the original image, wherein the pixel average value of the original pixel points is an average value of each first pixel value and each second pixel value of the original pixel points;
and generating a target image, wherein the pixel points of the target image are in one-to-one correspondence with the original pixel points of the original image, and the pixel values of the pixel points in the target image are pixel average values of the corresponding original pixel points in the original image.
In a possible implementation, the second pixel value is equal to a median of the gray values of the original pixel points, wherein the gray values of the original pixel points are arranged in order.
In one possible implementation, each original pixel point and a plurality of adjacent pixel points corresponding to the original pixel point form a matrix module, and the center of the matrix module is coincident with the corresponding original pixel point;
the matrix module comprises N multiplied by N pixel points, wherein N is an odd number larger than 3;
the average value of each original pixel point is the average value of the pixel values of the n×n pixel points.
In one possible implementation, obtaining a first pixel value of each original pixel point in the original image includes:
determining the number of adjacent pixel points surrounding each original pixel point, wherein the number of the adjacent pixel points is a preset value, and the preset value is smaller than a quantity threshold value;
and acquiring the first pixel values corresponding to the adjacent pixel points with the preset number.
In one possible implementation, constructing the original image from the first demodulation information includes:
and constructing an original two-dimensional image or an original two-dimensional matrix of the time-distance domain according to the first demodulation information.
In one possible implementation, the average filtering processing of the original image to obtain the target image includes:
performing mean value filtering processing on the original two-dimensional image to obtain a target two-dimensional image in a time-distance domain;
or, carrying out mean filtering treatment on the original two-dimensional matrix to obtain a target two-dimensional matrix in a time-distance domain.
In a second aspect, an embodiment of the present application further provides a distributed acoustic wave sensing system based on a mean filtering technology, where the distributed acoustic wave sensing system includes a demodulation unit and a controller, and the demodulation unit and the controller are connected through signals;
the demodulation unit is configured to collect backward Rayleigh scattering signals generated by vibration signals in the line of the sensing optical fiber within a preset time period, wherein the backward Rayleigh scattering signals comprise signals generated by the vibration signals in the distributed acoustic wave sensing system;
the demodulation unit is further configured to demodulate the collected backward Rayleigh scattering signals to obtain first demodulation information, wherein the first demodulation information comprises demodulation information of each position along the sensing optical fiber;
the controller is configured to construct an original image according to the first demodulation information, wherein the original image comprises images formed by the first demodulation information of each position along the sensing optical fiber in a preset time period;
the controller is further configured to perform mean value filtering processing on the original image to obtain a target image;
the controller is further configured to reconstruct second demodulation information from the target image, the second demodulation information including demodulation information after noise cancellation information for each location along the sensing fiber.
In a first aspect, an embodiment of the present application provides a distributed acoustic wave sensing measurement method based on a mean filtering technology, where an original image is constructed by using first demodulation information, then noise information in the original image is eliminated by using the original image through mean filtering, a target image with noise information eliminated is obtained, and then a second demodulation information is obtained after reconstructing the target image, and then the second demodulation information is a measurement result with noise information eliminated. Therefore, by the distributed acoustic wave sensing measurement method based on the mean value filtering technology, measurement errors caused by noise information can be reduced, and measurement accuracy can be improved.
In a second aspect, an embodiment of the present application further provides a distributed acoustic wave sensing system based on a mean filtering technology, where the sensing system has all the beneficial effects of the distributed acoustic wave sensing method of the first aspect, and is not described herein again.
Drawings
FIG. 1 is a schematic structural diagram of a distributed acoustic wave sensing system based on an average filtering technique according to an embodiment of the present disclosure;
FIG. 2 is a step diagram of a distributed acoustic wave sensing measurement method based on an average filtering technique according to an embodiment of the present application;
FIG. 3 is a diagram of an implementation step of S400 in FIG. 2;
FIG. 4 is a two-dimensional image corresponding to demodulation information of vibration signals measured by a distributed acoustic wave sensing system according to the related art;
fig. 5 is a two-dimensional image corresponding to demodulation information of a vibration signal measured by a distributed acoustic wave sensing system based on an average filtering technology according to an embodiment of the present application.
Reference numerals illustrate:
1-a laser emitting unit; 2-a circulator; a 3-sensing unit; a 4-demodulation unit;
a 101-laser; 102-an isolator; 103-an acousto-optic modulator; 1031-a function generator; 104-a first erbium-doped fiber amplifier; 105-a first filter;
301-sensing optical fibers; 302-a first piezoelectric ceramic;
401-a second erbium-doped fiber amplifier; 402-a second filter; 403-couplers; 404-a first faraday rotator mirror; 405-a second faraday rotator mirror; 406-a second piezoelectric ceramic; 407-detector; 408-acquisition card.
Detailed Description
The principle of the distributed acoustic wave sensing technology is to obtain the change of the physical quantity (such as sound, vibration and the like) to be detected by detecting the phase change of the Rayleigh scattered light along the sensing optical fiber. The distributed acoustic wave sensing system comprises a sensing optical fiber, and the characteristic information of the sensing optical fiber changes along with the changes of the external temperature, the strain and the vibration, so that the change of the surrounding environmental parameters can be sensed through the sensing optical fiber.
In the measuring process of the distributed acoustic wave sensing system, a laser emits pulse light to a sensing optical fiber, the pulse light can interfere with backward Rayleigh scattered light at a certain point along the sensing optical fiber, the change of physical quantities such as acoustic wave or vibration of the point can cause the change of the phase of the backward Rayleigh scattered light, when the pulse light interferes with the backward Rayleigh scattered light, the phase change of the backward Rayleigh scattered light can be influenced by random noise fluctuation such as phase noise, polarization noise and environmental noise of the pulse light, when the backward Rayleigh scattered light at each position along the sensing optical fiber after interference is demodulated, the obtained demodulation information can contain noise information generated by a plurality of random noise fluctuation, and the demodulation information is interfered by the noise information, so that measuring errors are brought.
Therefore, the embodiment of the application provides a distributed acoustic wave sensing system based on a mean value filtering technology and a measuring method thereof, so as to solve the technical problem that the obtained demodulation information is interfered by noise information when the distributed acoustic wave sensing system demodulates the information of each position along the transmission line in the prior art, thereby bringing about measuring errors.
Fig. 1 is a schematic structural diagram of a distributed acoustic wave sensing system based on an average filtering technology according to an embodiment of the present application.
In some examples, referring to fig. 1, the distributed acoustic wave sensing system generally includes a laser emitting unit 1, a circulator 2, a sensing unit 3, a demodulation unit 4, and a controller, where an output terminal of the laser emitting unit 1 is connected to a first input terminal of the circulator 2, a first output terminal of the circulator 2 is connected to an output terminal of the sensing unit 3, a second output terminal of the circulator 2 is connected to the demodulation unit 4, and an output terminal of the demodulation unit 4 is connected to the controller.
Illustratively, when the distributed acoustic wave sensing system in the above embodiment is used for measurement, the measurement process is as follows: the laser transmitting unit 1 transmits a laser signal, the laser signal is output to the sensing unit 3 through the first input end and the first output end of the circulator 2, the laser signal propagates along the sensing optical fiber 301 of the sensing unit 3 to detect a vibration signal in an environment to be detected, backward Rayleigh scattered light is generated, the backward Rayleigh scattered light is output to the demodulating unit 4 through the second output end of the circulator 2, the demodulating unit 4 demodulates the backward Rayleigh scattered light, and demodulated information is output to the controller.
Fig. 2 is a diagram of implementation steps of a distributed acoustic wave sensing measurement method based on an average filtering technique according to an embodiment of the present application. Fig. 3 is a diagram of an implementation step of S400 in fig. 2. The methods shown in fig. 2 and 3 can be applied to the distributed acoustic wave sensing system shown in fig. 1.
In some examples, referring to fig. 2 and 3, based on the distributed acoustic wave sensing system provided in the above embodiments, a measurement method of the distributed acoustic wave sensing system includes the steps of:
s100: the backward Rayleigh scattering signal generated by the vibration signal along the line of the sensing optical fiber 301 in a preset time period is collected.
For example, when testing the distributed acoustic wave sensing system, the distributed acoustic wave sensing system may be set up, and when testing the measurement method, a vibration signal may be applied to the first piezoelectric ceramic 302 on the sensing optical fiber 301 by the function generator 1031, and the distributed acoustic wave sensing system is used to collect the backward rayleigh scattering signal generated by the sensing optical fiber 301 along the line in a preset period of time.
S200: the collected backward Rayleigh scattering signal is demodulated to obtain first demodulation information, wherein the first demodulation information comprises demodulation information containing noise information at each position along the sensing optical fiber 301.
The collected backward Rayleigh scattering signal is subjected to phase demodulation to obtain first demodulation information.
S300: an original image is constructed from the first demodulation information, the original image including an image formed by sensing the first demodulation information at each position along the optical fiber 301 for a preset period of time.
Illustratively, the original two-dimensional image includes two-dimensional graphic information of a time-distance domain or two-dimensional matrix information of a time-distance domain.
It should be noted that, the first demodulation information is information obtained by demodulating a backward rayleigh scattering signal, where the backward rayleigh scattering signal is a signal generated by a vibration signal along the sensing optical fiber 301 in a preset time period, and the first demodulation information includes demodulation information of each position along the sensing optical fiber 301. Therefore, the time of the original two-dimensional image or the original two-dimensional matrix of the time-distance domain constructed by the first demodulation information corresponds to a preset time period, and the distance corresponds to each position along the sensing optical fiber 301.
S400: and carrying out mean filtering processing on the original image to obtain a target image.
The target image includes, for example, two-dimensional graphic information of a time-distance domain or two-dimensional matrix information of a time-distance domain.
It should be noted that, the target two-dimensional image is a two-dimensional image obtained by performing the mean value filtering processing on the original two-dimensional image, and the target two-dimensional matrix is a two-dimensional matrix obtained by performing the mean value filtering processing on the original two-dimensional matrix, so that the time in the target two-dimensional image and the time in the target two-dimensional matrix correspond to a preset time period, and the distance corresponds to each position along the sensing optical fiber 301.
S410: and acquiring first pixel values of all original pixel points in the original image, wherein the first pixel values comprise pixel values of adjacent pixel points of the original pixel points, the adjacent pixel points are pixel points surrounding the original pixel points, and the number of the adjacent pixel points is at least one.
Illustratively, a first pixel value of each original pixel in the original image is obtained, that is, a pixel value of an adjacent pixel surrounding each original pixel is obtained.
Illustratively, the step of obtaining the first pixel value is as follows:
and determining the number of adjacent pixel points surrounding each original pixel point, wherein the number of the adjacent pixel points is a preset value, and the preset value is smaller than a quantity threshold value.
And acquiring the first pixel values corresponding to the adjacent pixel points with the preset number.
S420: and acquiring a second pixel value of each original pixel point of the original image, wherein the second pixel value is the pixel value of the original pixel point.
Illustratively, the second pixel value is equal to the median of the gray values of the original pixel points. It is possible that the gray values are arranged in order from small to large, and then the intermediate value of the gray values is selected as the second pixel value.
According to the method and the device, the gray value of the original pixel point is used as the second pixel value, noise information in the original pixel point is removed more easily, and therefore a target image with a good denoising effect is obtained.
S430: and generating a pixel average value of each original pixel point in the original image, wherein the pixel average value of the original pixel points is the average value of each first pixel value and each second pixel value of the original pixel points.
Illustratively, each original pixel point and a plurality of adjacent pixel points corresponding to the original pixel point form a matrix module, and the center of the matrix module is coincident with the corresponding original pixel point.
The matrix module comprises N multiplied by N pixel points, wherein N is an odd number greater than or equal to 3.
The average value of each original pixel point is the average value of the pixel values of the n×n pixel points.
When N is 3, the matrix module has 9 pixels, wherein the original pixel is taken as a center, the rest 8 adjacent pixels are surrounded around the original pixel, and the 9 pixels together form a filtering window. The average pixel value of 9 pixel points in the filtering window is the pixel average value.
Of course, N may be 5, and when N is equal to 5, the corresponding matrix module has 25 pixels in total, wherein the original pixel is taken as a center, the remaining 24 adjacent pixels surround the original pixel, and the 25 pixels together form a filtering window.
S440: and generating a target image, wherein the pixel points of the target image are in one-to-one correspondence with the original pixel points of the original image, and the pixel values of the pixel points in the target image are pixel average values of the corresponding original pixel points in the original image.
It is possible to obtain a target image that can better eliminate noise information, the size of the filter window is generally selected from a small size, for example, a filter window with a size of 3×3 may be used first, and if the effect is not ideal, a filter window with a size of 5×5 may be selected until the size is selected to be smaller than the number threshold.
As the filter window becomes larger, the number of pixel points is increased, and the noise eliminating effect of the target image is correspondingly enhanced. Accordingly, as the number of pixels increases, the obtained target image becomes increasingly blurred, i.e., the target image definition becomes lower. When the number of the pixel points is larger than the number threshold, the definition of the image influences the definition of the target image, and further influences the content of the second demodulation information obtained after the target image is reconstructed. Therefore, the embodiment of the application can enhance the denoising effect while guaranteeing the definition of the target image through the setting of the quantity threshold value.
According to the method and the device for obtaining the target image, the pixel average value of each original pixel point is calculated, so that noise information on each original pixel point can be eliminated to obtain the pixel average value, the target image with the target pixel value can be further obtained, and the target image with the noise information eliminated can be further obtained.
S500: the second demodulation information is reconstructed from the target image, and includes the noise-removed demodulation information at each position along the sensing fiber 301.
S600: and judging the position of the vibration signal and the intensity of the vibration signal according to the second demodulation information.
The embodiment of the application provides a distributed acoustic wave sensing measurement method based on a mean value filtering technology, which comprises the steps of constructing an original image through first demodulation information, then carrying out mean value filtering processing on the original image to eliminate noise information in the original image, obtaining a target image after eliminating the noise information, and then carrying out reconstruction on the target image to obtain second demodulation information, wherein the second demodulation information is a measurement result after eliminating the noise information, so that the influence of random noise on the measurement result can be effectively eliminated, and high-performance demodulation information is obtained. Therefore, by the distributed acoustic wave sensing measurement method based on the mean value filtering technology, measurement errors caused by noise information can be reduced, and measurement accuracy can be improved.
The embodiment of the application also provides a distributed acoustic wave sensing system based on the mean value filtering technology, which comprises a demodulation unit 4 and a controller, wherein the demodulation unit 4 is connected with the controller through signals.
The demodulation unit 4 is configured to collect backward rayleigh scattering signals generated by the vibration signals along the sensing optical fiber 301 within a preset period of time, wherein the backward rayleigh scattering signals comprise signals generated by the vibration signals in the distributed acoustic wave sensing system.
The demodulation unit 4 is further configured to demodulate the collected backward rayleigh scattering signal, so as to obtain first demodulation information, where the first demodulation information includes demodulation information of each position along the sensing optical fiber 301.
The controller is configured to construct an original image from the first demodulation information, the original image including an image formed by sensing the first demodulation information at each position along the optical fiber 301 for a preset period of time.
The controller is further configured to perform a mean filtering process on the original image to obtain a target image.
The controller is further configured to reconstruct second demodulation information from the target image, the second demodulation information including demodulation information after noise cancellation information at various locations along the sensing fiber 301.
The embodiment of the application also provides a distributed acoustic wave sensing system based on the mean value filtering technology, and the measuring method in any one of the above technical schemes is adopted, so that the distributed acoustic wave sensing system has all the beneficial effects of the measuring method in any one of the above technical schemes, and is not repeated here.
In some examples, the distributed acoustic wave sensing system may include the following structure:
the laser emission unit 1 comprises a laser 101, an isolator 102, an acousto-optic modulator 103, a first erbium-doped fiber amplifier 104 and a first filter 105, wherein the output end of the laser 101 is connected with the input end of the isolator 102, the output end of the isolator 102 is connected with the input end of the acousto-optic modulator 103, the output end of the acousto-optic modulator 103 is connected with the input end of the first erbium-doped fiber amplifier 104, and the output end of the first erbium-doped fiber amplifier 104 is connected with the input end of the first filter 105. The laser 101 is configured to emit a laser signal to an input of the isolator 102; the isolator 102 is configured such that the laser beam is output unidirectionally by the isolator 102 to the acousto-optic modulator 103. The acousto-optic modulator 103 is connected to a function generator 1031, the function generator 1031 being configured to drive the acousto-optic modulator 103 to modulate the pulse width between pulses of the laser signal and the number of frequencies between pulses. The first erbium-doped fiber amplifier 104 is configured to amplify the laser signal output by the output terminal of the acousto-optic modulator 103. The first filter 105 is configured to filter the disturbance light of the laser signal.
The sensing unit 3 comprises a sensing optical fiber 301, the first output end of the circulator 2 is connected with the sensing optical fiber 301, and the sensing optical fiber 301 is configured to transmit laser signals and interfere with vibration signals along the sensing optical fiber 301 to generate backward Rayleigh scattering signals.
The demodulation unit 4 comprises a second erbium doped fiber amplifier 401, a second filter 402, a detector 407, an acquisition card 408, a coupler 403, a first faraday rotator mirror 404 and a second faraday rotator mirror 405. The input end of the second erbium-doped fiber amplifier 401 is connected with the second output end of the circulator 2, the output end of the second erbium-doped fiber amplifier 401 is connected with the input end of the second filter 402, the output end of the second filter 402 is connected with the first end of the coupler 403, the second end of the coupler 403 is connected with the input end of the detector 407, the output end of the detector 407 is connected with the input end of the acquisition card 408, the third end of the coupler 403 is connected with the first faraday rotation mirror 404, and the fourth end of the coupler 403 is connected with the second faraday rotation mirror 405.
By adopting the distributed acoustic wave sensing system provided by the embodiment, in the measuring process, a laser signal is input by the laser 101, sequentially passes through the isolator 102, the acousto-optic modulator 103, the first erbium-doped optical fiber amplifier 104 and the first filter 105, and then is output to the sensing optical fiber 301 through the first output end of the circulator 2, a backward Rayleigh scattering signal is generated by a vibration signal along the sensing optical fiber 301 within a preset time, and then is output to the demodulation unit 4 through the first input end and the second output end of the circulator 2.
The backward rayleigh scattering signal input to the demodulation unit 4 enters the first faraday rotation mirror 404 through the second erbium-doped fiber amplifier 401 and the second filter 402, a part of the first end of the coupler 403 and the third end of the coupler 403 are reflected to the third end of the coupler 403 by the first faraday rotation mirror 404, the other part of the backward rayleigh scattering signal is output to the second faraday rotation mirror 405 through the fourth end of the coupler 403, the second faraday rotation mirror 405 is provided with the second piezoelectric ceramic 406, the carrier signal is loaded through the second piezoelectric ceramic 406 to modulate the other part of the backward rayleigh scattering signal, the modulated backward rayleigh scattering signal is reflected to the fourth end of the coupler 403 by the second faraday rotation mirror 405, the backward rayleigh scattering signal of the fourth end of the coupler 403 and the backward rayleigh scattering signal of the third end of the coupler 403 are all output to the second end of the coupler 403 and are mutually interfered and collected by the collecting card 408, the collecting card 408 is connected with the controller, the collected signal is output to the controller, the demodulated information generated by the backward rayleigh scattering light is processed in the controller, and the information is eliminated.
Fig. 4 is a two-dimensional image corresponding to demodulation information of vibration signals measured using a distributed acoustic wave sensing system in the related art. Fig. 5 is a two-dimensional image corresponding to demodulation information of a vibration signal measured by a distributed acoustic wave sensing system based on an average filtering technology according to an embodiment of the present application.
The vibration signal measured by the distributed acoustic wave sensor system may be a vibration signal applied to the first piezoelectric ceramic 302 on the sensing fiber 301 at the function generator 1031. For example, the vibration signal measured by the distributed acoustic wave sensing system in the related art in fig. 4 and the vibration signal measured by the distributed acoustic wave sensing system provided in the embodiment of the present application in fig. 5 are the same vibration signal applied to the sensing optical fiber 301 by the first piezoelectric ceramic 302, which is hereinafter referred to as the first vibration signal.
When the distributed acoustic wave sensing system provided by the above embodiment is used to measure the first vibration signal, a two-dimensional image in fig. 5 corresponding to the demodulation information can be obtained.
When the distributed acoustic wave sensing system in the related art is used to measure the first vibration signal, a two-dimensional image in fig. 4 corresponding to the demodulation information can be obtained.
Referring to fig. 4, the schematic diagram in fig. 4 is that the distributed acoustic wave sensing system in the related art is used to measure the first vibration signal applied to the sensing optical fiber 301, and it can be seen from observing fig. 4 that there are multiple highlight disturbances a in the area a and multiple disturbances in the vibration signal simulation diagram in the area B in fig. 4, so that the resolution of the vibration signal simulation diagram in the area B is lower.
Referring to fig. 5, the schematic diagram in fig. 5 is that the distributed acoustic wave sensing system in the embodiment of the present application is used to measure the first vibration signal along the sensing optical fiber 301, and it can be seen from observing fig. 5 that, compared with fig. 4, the highlight interference in the area A1 corresponding to the area a in fig. 5 is reduced, and similarly, the highlight interference in the area B1 corresponding to the area B in fig. 5 is also reduced, and the resolution of the vibration signal diagram in the area B1 is higher, so that it can be obtained that the distributed acoustic wave sensor provided in the embodiment of the present application has a better denoising effect and a higher measurement accuracy.
Claims (8)
1. The distributed acoustic wave sensing measurement method based on the mean value filtering technology is characterized by comprising the following steps of:
collecting backward Rayleigh scattering signals generated by vibration signals along the sensing optical fiber within a preset time period;
demodulating the collected backward Rayleigh scattering signals to obtain first demodulation information, wherein the first demodulation information comprises demodulation information of each position along the sensing optical fiber;
constructing an original image according to the first demodulation information, wherein the original image comprises images formed by the first demodulation information of all positions along the sensing optical fiber in the preset time period;
performing mean filtering processing on the original image to obtain a target image;
reconstructing second demodulation information according to the target image, wherein the second demodulation information comprises demodulation information after noise elimination information of all positions along the sensing optical fiber.
2. The method for distributed acoustic wave sensing measurement based on the mean value filtering technology according to claim 1, wherein the step of performing the mean value filtering on the original image to obtain the target image includes:
acquiring first pixel values of original pixel points in the original image, wherein the first pixel values comprise pixel values of adjacent pixel points of the original pixel points, the adjacent pixel points are pixel points surrounding the original pixel points, and the number of the adjacent pixel points is at least one;
acquiring a second pixel value of each original pixel point of the original image, wherein the second pixel value is the pixel value of the original pixel point;
generating a pixel average value of each original pixel point in the original image, wherein the pixel average value of the original pixel points is an average value of each first pixel value and each second pixel value of the original pixel points;
generating a target image, wherein the pixel points of the target image are in one-to-one correspondence with the original pixel points of the original image, and the pixel values of the pixel points in the target image are pixel average values of the corresponding original pixel points in the original image.
3. The method of claim 2, wherein the second pixel value is equal to a median value of gray values of the original pixels, and wherein the gray values of the original pixels are arranged in sequence.
4. A distributed acoustic wave sensing measurement method based on a mean value filtering technique according to claim 2 or 3, wherein each original pixel point and a plurality of adjacent pixel points corresponding to the original pixel point form a matrix module, and the center of the matrix module coincides with the corresponding original pixel point;
the matrix module comprises N multiplied by N pixel points, wherein N is an odd number larger than 3;
the average value of each original pixel point is the average value of the pixel values of N multiplied by N pixel points.
5. The method for distributed acoustic wave sensing measurement based on the mean value filtering technique according to claim 3, wherein the obtaining the first pixel value of each original pixel point in the original image includes:
determining the number of the adjacent pixel points surrounding each original pixel point, wherein the number of the adjacent pixel points is a preset value, and the preset value is smaller than a quantity threshold value;
and acquiring the first pixel values corresponding to the adjacent pixel points with the preset number.
6. A distributed acoustic wave sensing measurement method based on a mean value filtering technique according to any one of claims 1-3, wherein said constructing an original image from said first demodulation information comprises:
and constructing an original two-dimensional image or an original two-dimensional matrix of the time-distance domain according to the first demodulation information.
7. The method for distributed acoustic wave sensing measurement based on the mean value filtering technique according to claim 6, wherein the step of performing the mean value filtering on the original image to obtain the target image includes:
performing mean value filtering processing on the original two-dimensional image to obtain a target two-dimensional image in a time-distance domain;
or, carrying out mean value filtering processing on the original two-dimensional matrix to obtain a target two-dimensional matrix in a time-distance domain.
8. The distributed acoustic wave sensing system based on the mean value filtering technology is characterized by comprising a demodulation unit and a controller, wherein the demodulation unit is connected with the controller through signals;
the demodulation unit is configured to collect backward Rayleigh scattering signals generated by vibration signals in the line of the sensing optical fiber within a preset time period, wherein the backward Rayleigh scattering signals comprise signals generated by the vibration signals in the distributed acoustic wave sensing system;
the demodulation unit is further configured to demodulate the collected backward Rayleigh scattering signals to obtain first demodulation information, wherein the first demodulation information comprises demodulation information of each position along the sensing optical fiber;
the controller is configured to construct an original image according to the first demodulation information, wherein the original image comprises images formed by the first demodulation information of all positions along the sensing optical fiber in the preset time period;
the controller is further configured to perform mean filtering processing on the original image to obtain a target image;
the controller is further configured to reconstruct second demodulation information from the target image, the second demodulation information including noise-canceled demodulation information for each location along the sensing fiber.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310664909.6A CN116380140B (en) | 2023-06-07 | 2023-06-07 | Distributed acoustic wave sensing system based on mean value filtering technology and measuring method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202310664909.6A CN116380140B (en) | 2023-06-07 | 2023-06-07 | Distributed acoustic wave sensing system based on mean value filtering technology and measuring method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN116380140A true CN116380140A (en) | 2023-07-04 |
| CN116380140B CN116380140B (en) | 2023-11-03 |
Family
ID=86975468
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202310664909.6A Active CN116380140B (en) | 2023-06-07 | 2023-06-07 | Distributed acoustic wave sensing system based on mean value filtering technology and measuring method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116380140B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220283021A1 (en) * | 2019-11-13 | 2022-09-08 | Tianjin University | Differential cotdr distributed acoustic sensing device and method based on heterogeneous double-sideband chirped-pulses |
| CN117029999A (en) * | 2023-10-09 | 2023-11-10 | 山东省科学院激光研究所 | Distributed acoustic wave sensing system and measuring method based on pulse modulation technology |
| CN117708506A (en) * | 2024-02-05 | 2024-03-15 | 山东省科学院激光研究所 | Method and system for eliminating deterioration effect caused by distributed acoustic wave sensing coherent fading |
Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2829298A1 (en) * | 2011-02-18 | 2012-08-23 | Hexagon Technology Center Gmbh | Fast image enhancement and three-dimensional depth calculation |
| CN102663719A (en) * | 2012-03-19 | 2012-09-12 | 西安电子科技大学 | Bayer-pattern CFA image demosaicking method based on non-local mean |
| CN106441386A (en) * | 2016-09-29 | 2017-02-22 | 西南交通大学 | Data processing method and device based on distributed fiber sensing system |
| CN106679790A (en) * | 2016-12-05 | 2017-05-17 | 华南理工大学 | Cross-correlation demodulation method for improving sensitivity of distributed optical fiber vibration sensing |
| CN107270952A (en) * | 2017-07-27 | 2017-10-20 | 天津求实飞博科技有限公司 | Based on the distributed destabilization sensing signal processing method of probe beam deflation long-distance optical fiber |
| CN108875684A (en) * | 2018-06-29 | 2018-11-23 | 电子科技大学 | Train operation state method for parameter estimation based on optical fiber sensing time-frequency figure processing |
| CN108981767A (en) * | 2018-08-17 | 2018-12-11 | 山东省科学院激光研究所 | Optical fiber distributed type monitors system and method |
| WO2020237644A1 (en) * | 2019-05-31 | 2020-12-03 | 深圳市晟视科技有限公司 | Fpga architecture-based realtime depth of field synthesis algorithm and system |
| CN112033522A (en) * | 2020-08-10 | 2020-12-04 | 太原理工大学 | Sound signal detection system and method of distributed optical fiber sensor |
| CN112378432A (en) * | 2020-10-29 | 2021-02-19 | 太原理工大学 | Distributed optical fiber Raman sensing device and method based on noise matched filtering |
| CN112747815A (en) * | 2021-01-06 | 2021-05-04 | 苏州光格科技股份有限公司 | Coherent fading noise suppression method in distributed optical fiber acoustic wave sensing system |
| WO2021093181A1 (en) * | 2019-11-13 | 2021-05-20 | 天津大学 | Differential cotdr distributed acoustic sensing device and method based on heterogeneous double-sideband chirped pulse |
| CN112884662A (en) * | 2021-01-05 | 2021-06-01 | 杭州国测测绘技术有限公司 | Three-dimensional digital map image processing method based on aerial image of aircraft |
| CN115622626A (en) * | 2022-12-20 | 2023-01-17 | 山东省科学院激光研究所 | Distributed sound wave sensing voice information recognition system and method |
| CN115824378A (en) * | 2022-10-09 | 2023-03-21 | 上海交通大学 | Vibration detection method of high-frequency-response distributed optical fiber acoustic wave sensor |
| US20230138853A1 (en) * | 2020-01-27 | 2023-05-04 | The Johns Hopkins University | Direct energy windowing for photon counting detectors |
-
2023
- 2023-06-07 CN CN202310664909.6A patent/CN116380140B/en active Active
Patent Citations (16)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2829298A1 (en) * | 2011-02-18 | 2012-08-23 | Hexagon Technology Center Gmbh | Fast image enhancement and three-dimensional depth calculation |
| CN102663719A (en) * | 2012-03-19 | 2012-09-12 | 西安电子科技大学 | Bayer-pattern CFA image demosaicking method based on non-local mean |
| CN106441386A (en) * | 2016-09-29 | 2017-02-22 | 西南交通大学 | Data processing method and device based on distributed fiber sensing system |
| CN106679790A (en) * | 2016-12-05 | 2017-05-17 | 华南理工大学 | Cross-correlation demodulation method for improving sensitivity of distributed optical fiber vibration sensing |
| CN107270952A (en) * | 2017-07-27 | 2017-10-20 | 天津求实飞博科技有限公司 | Based on the distributed destabilization sensing signal processing method of probe beam deflation long-distance optical fiber |
| CN108875684A (en) * | 2018-06-29 | 2018-11-23 | 电子科技大学 | Train operation state method for parameter estimation based on optical fiber sensing time-frequency figure processing |
| CN108981767A (en) * | 2018-08-17 | 2018-12-11 | 山东省科学院激光研究所 | Optical fiber distributed type monitors system and method |
| WO2020237644A1 (en) * | 2019-05-31 | 2020-12-03 | 深圳市晟视科技有限公司 | Fpga architecture-based realtime depth of field synthesis algorithm and system |
| WO2021093181A1 (en) * | 2019-11-13 | 2021-05-20 | 天津大学 | Differential cotdr distributed acoustic sensing device and method based on heterogeneous double-sideband chirped pulse |
| US20230138853A1 (en) * | 2020-01-27 | 2023-05-04 | The Johns Hopkins University | Direct energy windowing for photon counting detectors |
| CN112033522A (en) * | 2020-08-10 | 2020-12-04 | 太原理工大学 | Sound signal detection system and method of distributed optical fiber sensor |
| CN112378432A (en) * | 2020-10-29 | 2021-02-19 | 太原理工大学 | Distributed optical fiber Raman sensing device and method based on noise matched filtering |
| CN112884662A (en) * | 2021-01-05 | 2021-06-01 | 杭州国测测绘技术有限公司 | Three-dimensional digital map image processing method based on aerial image of aircraft |
| CN112747815A (en) * | 2021-01-06 | 2021-05-04 | 苏州光格科技股份有限公司 | Coherent fading noise suppression method in distributed optical fiber acoustic wave sensing system |
| CN115824378A (en) * | 2022-10-09 | 2023-03-21 | 上海交通大学 | Vibration detection method of high-frequency-response distributed optical fiber acoustic wave sensor |
| CN115622626A (en) * | 2022-12-20 | 2023-01-17 | 山东省科学院激光研究所 | Distributed sound wave sensing voice information recognition system and method |
Non-Patent Citations (2)
| Title |
|---|
| QIN, ZG 等: "A fully distributed fiber optic sensor for simultaneous relative humidity and temperature measurement with polyimide-coated polarization maintaining fiber", SENSORS AND ACTUATORS B-CHEMICAL, vol. 373 * |
| 董贯雷等: "基于分布式光纤传感系统的有载变压器故障检测技术研究", 《山东科学》 * |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20220283021A1 (en) * | 2019-11-13 | 2022-09-08 | Tianjin University | Differential cotdr distributed acoustic sensing device and method based on heterogeneous double-sideband chirped-pulses |
| CN117029999A (en) * | 2023-10-09 | 2023-11-10 | 山东省科学院激光研究所 | Distributed acoustic wave sensing system and measuring method based on pulse modulation technology |
| CN117029999B (en) * | 2023-10-09 | 2024-01-30 | 山东省科学院激光研究所 | Distributed acoustic wave sensing system and measuring method based on pulse modulation technology |
| CN117708506A (en) * | 2024-02-05 | 2024-03-15 | 山东省科学院激光研究所 | Method and system for eliminating deterioration effect caused by distributed acoustic wave sensing coherent fading |
| CN117708506B (en) * | 2024-02-05 | 2024-04-26 | 山东省科学院激光研究所 | Method and system for eliminating deterioration effect caused by distributed acoustic wave sensing coherent fading |
Also Published As
| Publication number | Publication date |
|---|---|
| CN116380140B (en) | 2023-11-03 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN116380140B (en) | Distributed acoustic wave sensing system based on mean value filtering technology and measuring method thereof | |
| CN110389170B (en) | Train component crack damage detection method and system based on Lamb wave imaging | |
| Lu et al. | Distributed vibration sensor based on coherent detection of phase-OTDR | |
| US5384635A (en) | Remote sensing in optical fiber networks by synchronously detecting backscattered optical signals | |
| EP3477266B1 (en) | Distributed acoustic sensing device using different coherent interrogating light patterns, and corresponding sensing method | |
| CN108225541A (en) | The distributed fiberoptic sensor and foreign body intrusion signal for identifying foreign body intrusion perceive processing method | |
| CN107907151A (en) | Phi OTDR and sensing method based on optical frequency modulation and direct detection | |
| CN108415067A (en) | A kind of earthquake wave measuring system based on microstructured optical fibers distribution sound wave sensing | |
| CN114543973B (en) | Distributed ultrahigh frequency vibration signal measurement method and optical fiber sensor | |
| CN116399379B (en) | Distributed optical fiber acoustic wave sensing system and measuring method thereof | |
| CN109391321A (en) | Disturbance positioning method in a kind of phase sensitive OTDR sensing | |
| CN116818085B (en) | Distributed optical fiber acoustic wave sensing system based on weak grating and measuring method thereof | |
| WO2020102311A1 (en) | Optical fiber vibration sensor with improved signal to noise ratio management | |
| US20240201008A1 (en) | Distributed Acoustic Sensing Voice Message Recognition System and Method | |
| CN115824378A (en) | Vibration detection method of high-frequency-response distributed optical fiber acoustic wave sensor | |
| CN210567574U (en) | Oil and gas pipeline leakage monitoring system based on optical fiber | |
| CN115165071A (en) | Method and system for realizing accurate vibration positioning based on machine learning and phase segmentation difference | |
| CN112880711B (en) | Distributed optical fiber sensing method and system based on double pulse modulation | |
| CN113237431B (en) | Measurement method for improving distributed spatial resolution of OFDR system | |
| WO2020188888A1 (en) | Vibration detection optical fiber sensor and vibration detection method | |
| WO2020054143A1 (en) | Vibration detection optical fiber sensor and vibration detection method | |
| CN108692766B (en) | BFS measuring device, method and distributed fiber-optic sensor system | |
| CN113091784A (en) | Phase demodulation method for direct detection type phi-OTDR | |
| CN117708506B (en) | Method and system for eliminating deterioration effect caused by distributed acoustic wave sensing coherent fading | |
| CN117029999B (en) | Distributed acoustic wave sensing system and measuring method based on pulse modulation technology |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |