WO2017141732A1 - Bubble parameter identifying device, bubble parameter identifying method, and program - Google Patents

Bubble parameter identifying device, bubble parameter identifying method, and program Download PDF

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Publication number
WO2017141732A1
WO2017141732A1 PCT/JP2017/003967 JP2017003967W WO2017141732A1 WO 2017141732 A1 WO2017141732 A1 WO 2017141732A1 JP 2017003967 W JP2017003967 W JP 2017003967W WO 2017141732 A1 WO2017141732 A1 WO 2017141732A1
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bubble
amplitude
reflected
wave
reflected wave
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PCT/JP2017/003967
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French (fr)
Japanese (ja)
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貴裕 中野
浩之 細谷
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三菱重工業株式会社
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Publication of WO2017141732A1 publication Critical patent/WO2017141732A1/en

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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/02—Analysing fluids
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
    • G01N29/44—Processing the detected response signal, e.g. electronic circuits specially adapted therefor

Definitions

  • the present invention relates to a bubble parameter specifying device, a bubble parameter specifying method, and a program that specify parameters related to bubbles included in a measurement target.
  • Patent Document 1 discloses a method for obtaining the amount of bubbles contained in water and the void ratio in water. Specifically, Patent Document 1 discloses irradiating ultrasonic waves into water and obtaining the amount and diameter of bubbles based on the reflected waves.
  • the intensity of the reflected wave of the ultrasonic wave irradiated into the water containing bubbles can be obtained based on the intensity of the irradiated ultrasonic wave and the reflection coefficient according to the bubble diameter.
  • the intensity of the ultrasonic wave is different near the center and near the end of the ultrasonic beam, the intensity of the reflected wave received varies depending on the position of the bubble with respect to the ultrasonic beam. Specifically, the intensity of the reflected wave by the bubble becomes relatively smaller as the position of the bubble is further away from the center of the ultrasonic beam. For this reason, in the method described in Patent Document 1, since the calculated bubble diameter is not accurate, the void ratio calculated based on the bubble diameter may be inaccurate.
  • An object of the present invention is to provide a bubble parameter identification device, a bubble parameter identification method, and a program capable of accurately identifying parameters relating to bubbles included in a measurement target.
  • the bubble parameter specifying device is a bubble parameter specifying device that specifies a parameter relating to a bubble included in a measurement target, and is a reflected wave of a transmission wave transmitted toward the measurement target.
  • a reflected wave receiving unit that extracts a bubble reflected wave that is a reflected wave reflected by a bubble included in the measurement object from the received reflected wave, and the extracted bubble reflection
  • An amplitude identification unit that identifies the amplitude of the wave
  • an extraction number information generation unit that generates extraction number information indicating the relationship between the amplitude of the plurality of bubble reflected waves and the number of extractions, Included in the measurement object based on the appearance rate information indicating the relationship between the amplitude and the appearance rate of the bubble reflected wave observed when the transmission wave is irradiated to the bubble having the bubble diameter, and the specified appearance rate Bubbles
  • a bubble parameter specifying unit for specifying the number of each cell diameter.
  • the bubble parameter specifying device is the time from the irradiation time of the transmission wave to the reception time of the bubble reflection wave for each of the extracted bubble reflection waves. It may further include a propagation time specifying unit for specifying the propagation time.
  • the bubble parameter specifying device specifies the reflected bubble reflected from the bubble included in the measurement target based on the propagation time.
  • the extraction number information generation unit further includes extraction number information indicating a relationship between the amplitude of the bubble reflected wave specified by the in-target bubble specification unit and the extraction number. It's okay.
  • the amplitude of each of the plurality of bubble reflected waves specified by the amplitude specifying unit is set to the corresponding propagation time.
  • An amplitude normalization unit that normalizes based on the amplitude may be further provided.
  • the bubble parameter identification unit includes a weighted sum of appearance rates for each amplitude indicated by the appearance rate information.
  • the weight coefficient for each amplitude used for the calculation of the weighted sum may be specified so as to approximate the number of extraction for each amplitude indicated by the extraction number information.
  • the bubble parameter specifying unit multiplies the weight coefficient for each amplitude by the total number of extractions of the bubble reflected waves.
  • the number of bubbles included in the measurement object for each bubble diameter may be specified.
  • the bubble parameter specifying device is the number of bubbles included in the measurement target specified by the bubble parameter specifying unit for each bubble diameter.
  • a void ratio specifying unit that specifies the void ratio of the measurement target.
  • the bubble parameter specifying device according to any one of the first to seventh aspects further includes an envelope processing unit that specifies an envelope of the reflected wave, and the bubble reflected wave
  • the extraction unit may extract the plurality of bubble reflected waves based on the peak of the envelope.
  • the amplitude specifying unit may specify the amplitude based on an amplitude of a peak of the envelope.
  • the bubble parameter identification unit includes the plurality of measurement objects having different depths.
  • the number of bubbles contained in each bubble diameter may be specified by obtaining the sum of the number of bubbles contained in the measurement target at each depth.
  • the bubble parameter specifying unit is configured so that each of the depths is based on the appearance rate information obtained in advance for each depth. You may specify by calculating
  • the transmission wave is transmitted as a longitudinal wave through a steel plate, and the transmission wave is in the steel plate.
  • the transverse wave refraction angle may be 40 degrees or more and 45 degrees or less.
  • the bubble parameter specifying method is a bubble parameter specifying method for specifying a parameter relating to a bubble included in a measurement target, and a reflected wave of a transmission wave transmitted toward the measurement target
  • a reflected wave receiving step for extracting a plurality of bubble reflected waves that are reflected waves reflected by the bubbles included in the measurement object from the reflected wave, and a plurality of the extracted bubble reflected waves
  • An amplitude step for specifying the amplitude of the bubble reflection wave, an extraction number information generation step for generating extraction number information indicating the relationship between the amplitude of the plurality of bubble reflection waves and the extraction number, and a plurality of bubble diameters are obtained in advance.
  • the program receives the reflected wave of the transmission wave transmitted to the measurement target by the computer of the bubble parameter specifying device that specifies the parameter relating to the bubble included in the measurement target.
  • a reflected wave receiving unit a bubble reflected wave extracting unit that extracts a plurality of bubble reflected waves, which are reflected waves reflected by bubbles included in the measurement object, from the reflected wave, and amplitudes of the extracted bubble reflected waves
  • An amplitude identification unit that identifies the number of extractions
  • an extraction number information generation unit that generates extraction number information indicating the relationship between the amplitudes of the plurality of bubble reflected waves and the number of extractions.
  • the bubbles included in the measurement object based on the appearance rate information indicating the relationship between the amplitude and the appearance rate of the bubble reflected wave observed when the transmission wave is irradiated to the bubbles having the air bubble and the specified appearance rate
  • the bubble parameter specifying device specifies the number of bubbles included in the measurement target for each bubble diameter based on the amplitude and appearance rate of the bubble reflected wave for each bubble diameter. Thereby, the bubble parameter specifying device can specify the parameter regarding the bubble in view of the variation in the intensity of the bubble reflected wave.
  • FIG. 1 is a diagram illustrating a configuration of a bubble parameter specifying system according to the first embodiment.
  • the bubble parameter specifying system 1 specifies the void ratio in the water near the bottom B of the ship.
  • the void ratio is a parameter indicating the volume ratio of bubbles contained per unit volume of fluid. That is, the bubble parameter specifying system 1 according to the first embodiment uses water near the ship bottom B as a measurement target.
  • the bubble parameter specifying system 1 includes an ultrasonic probe 100 and a bubble parameter specifying device 200.
  • the ultrasonic probe 100 transmits an ultrasonic wave at a predetermined angle with respect to the ship bottom B and receives a reflected wave of the ultrasonic wave.
  • the bubble parameter specifying device 200 specifies the void ratio in the water near the bottom B based on the reflected wave received by the ultrasonic probe 100.
  • the ultrasonic probe 100 is installed on the bottom B of the ship.
  • the ultrasonic probe 100 includes a probe main body 101 that transmits and receives longitudinal ultrasonic waves, and a spacer 102 that defines an angle of the probe main body 101 with respect to the ship bottom B. . That is, the ultrasonic wave emitted from the probe body 101 is reflected on the boundary surface between the spacer 102 and the ship bottom B, the boundary surface between the ship bottom B and water, and the boundary surface between water and bubbles.
  • the reflected wave reflected at the boundary surface between water and bubbles is referred to as a bubble reflected wave.
  • the probe body 101 is attached at an appropriate angle that can suppress the influence of such multiple reflection and increase the amount of transmission of acoustic energy into water.
  • the transverse wave refraction angle at the ship bottom B is an angle within a range of 40 degrees or more and 45 degrees or less.
  • the probe main body 101 is preferably installed so that the transverse wave refraction angle is 40 degrees.
  • FIG. 2 is a graph showing the relationship between the refraction angle of ultrasonic waves in steel and the echo level of bubble reflected waves.
  • FIG. 3 is a diagram showing the relationship between the refraction angle of the ultrasonic wave in steel and the echo ratio of the bubble reflected wave with respect to the entire reflected wave. 2 and 3, the echo level of the bubble reflected wave and the echo ratio of the bubble reflected wave with respect to the entire reflected wave are maximized when the transverse wave refraction angle ⁇ at the bottom B is 40 degrees. Since 40 degrees is a critical angle, no longitudinal wave component is generated during ultrasonic propagation from the probe body 101 to the ship bottom.
  • the longitudinal wave component is not included in the reflected wave by installing the probe body 101 so that the transverse wave refraction angle ⁇ is 40 degrees or more. That is, the influence of multiple reflection can be suppressed by installing the probe body 101 so that the transverse wave refraction angle ⁇ is 40 degrees or more.
  • the transverse wave refraction angle ⁇ exceeds 45 degrees, the echo level of the bubble reflected wave is less than 90% of the echo level obtained when the transverse wave refraction angle ⁇ is 40 degrees. That is, by setting the probe body 101 so that the transverse wave refraction angle ⁇ is 45 degrees or less, it is possible to prevent a decrease in the amount of transmission of acoustic energy into water.
  • the mounting angle ⁇ of the probe main body 101 (the angle of the perpendicular of the ultrasonic wave transmitting surface of the probe main body 101 with respect to the vertical line) at which the transverse wave refraction angle ⁇ is 40 degrees is 28 degrees. is there.
  • the bubble parameter specifying device 200 includes a probe control unit 201, a reflected wave recording unit 202, a reflected wave storage unit 203, a bubble reflected wave extraction unit 204, a propagation time specifying unit 205, an in-target bubble specifying unit 206, and an amplitude specifying unit 207. , An amplitude normalization unit 208, an extraction number information generation unit 209, a histogram storage unit 210, a bubble parameter specification unit 211, and a void rate specification unit 212.
  • the probe control unit 201 outputs an instruction to transmit ultrasonic waves to the ultrasonic probe 100.
  • the probe control unit 201 receives the waveform of the reflected wave of the ultrasonic wave transmitted from the ultrasonic probe 100 from the ultrasonic probe 100. Specifically, the probe control unit 201 amplifies the analog signal output from the ultrasonic probe 100 and converts it into a digital signal.
  • the probe control unit 201 is an example of a reflected wave receiving unit.
  • the reflected wave recording unit 202 records the waveform of the reflected wave received by the probe control unit 201 in the reflected wave storage unit 203 in association with the transmission time (irradiation time) of the ultrasonic wave.
  • the waveform of the reflected wave is specified by the relationship between the reception time of the reflected wave and the level.
  • the reflected wave storage unit 203 stores the reflected wave of the ultrasonic wave for each transmission time of the ultrasonic wave.
  • the bubble reflected wave extraction unit 204 and the bubble reflected wave extraction unit 204 extract the bubble reflected wave from the reflected wave stored in the reflected wave storage unit 203.
  • the propagation time identifying unit 205 identifies the propagation time that is the time from the transmission time of the ultrasonic wave to the reception time of the bubble reflected wave.
  • the in-target bubble specifying unit 206 specifies bubbles that exist within the range that is the target of specifying the bubble parameter.
  • the amplitude specifying unit 207 specifies the amplitude of the bubble reflected wave extracted by the bubble reflected wave extracting unit 204. Specifically, the amplitude specifying unit 207 specifies the maximum value of the envelope of the bubble reflected wave as the amplitude.
  • the amplitude normalization unit 208 normalizes the amplitude specified by the amplitude specification unit 207 according to the propagation time. The reflected ultrasonic wave is attenuated as the distance to the reflection position is longer. Therefore, the amplitude normalization unit 208 can reduce the influence of attenuation according to the position of the bubble by normalizing the amplitude.
  • the extraction number information generation unit 209 generates extraction number information indicating the extraction number for each amplitude range of the bubble reflected wave.
  • the histogram storage unit 210 stores a histogram indicating the relationship between the bubble reflected wave reflected by the bubble and the number of appearances in association with the bubble diameter and the bubble depth.
  • the histogram is obtained in advance by simulation or experiment.
  • the “depth” is a distance in the direction perpendicular to the transmission surface of the probe main body 101.
  • an example of a method for generating a histogram indicating the relationship between the amplitude of the bubble reflected wave and the number of appearances thereof by simulation will be described.
  • the operator creates a model in which the ultrasonic probe 100 is installed on a steel plate having the same thickness as the ship bottom B, and one bubble having a predetermined diameter exists in water.
  • the positions of the bubbles in the model are provided at random positions on a plane parallel to the ultrasonic irradiation surface at a predetermined depth.
  • the worker causes the simulator to execute an acoustic simulation using the ultrasonic probe 100 using the model. Thereby, the simulator can generate
  • the operator shows the relationship between the amplitude of the bubble reflected wave reflected by the bubble and the number of appearances of the bubble having a predetermined diameter existing at a predetermined depth by executing the simulation a plurality of times. Generate a histogram. The operator executes the generation of the histogram according to the above procedure for bubbles having a plurality of diameters and a plurality of depths.
  • the histogram stored in the histogram storage unit 210 is an appearance indicating the relationship between the amplitude and the appearance rate of the bubble reflected wave, which is obtained in advance for each bubble diameter and observed when the transmission wave is irradiated to the bubble having the bubble diameter. It is an example of rate information.
  • the bubble parameter specifying unit 211 specifies the relationship between the diameter and the number of bubbles included in the measurement target based on the extraction number information generated by the extraction number information generation unit 209 and the histogram stored in the histogram storage unit 210. .
  • the relationship between the diameter and the number of bubbles included in the measurement target is an example of a parameter related to bubbles.
  • the void ratio specifying unit 212 calculates the void ratio to be measured based on the relationship between the diameter and the number of bubbles specified by the bubble parameter specifying unit 211.
  • FIG. 4 is a flowchart showing a void ratio calculation process according to the first embodiment.
  • the probe control unit 201 intermittently sends an ultrasonic wave transmission instruction to the ultrasonic probe 100 a plurality of times (for example, several hundred to several times). 1000 times) (step S1).
  • the ultrasonic probe 100 executes transmission of ultrasonic waves and reception of reflected waves a plurality of times.
  • the probe control unit 201 receives a plurality of reflected wave waveforms from the ultrasonic probe 100 (step S2).
  • the reflected wave recording unit 202 records the reflected wave waveform received by the probe control unit 201 in the reflected wave storage unit 203 in association with the transmission time of the ultrasonic wave (step S3).
  • the bubble parameter specifying device 200 selects the reflected wave waveforms stored in the reflected wave storage unit 203 one by one, and executes the processing from step S5 to step S10 shown below for each selected waveform (step S4). ).
  • the bubble reflected wave extraction unit 204 performs envelope processing on the waveform of the reflected wave selected in step S4 (step S5).
  • the bubble reflected wave extraction unit 204 extracts each peak of the envelope of the reflected wave as a bubble reflected wave (step S6).
  • the propagation time specifying unit 205 determines each bubble reflection from the transmission time of the ultrasonic wave associated with the reflected wave selected in step S4 and the reception time of each bubble reflected wave extracted by the bubble reflected wave extraction unit 204.
  • a wave propagation time (TOF: Time Of Fright) is specified (step S7).
  • the in-target bubble specifying unit 206 reflects a bubble reflected from the bubble included in the measurement target when the propagation time specified by the propagation time specifying unit 205 is present in the predetermined evaluation target section.
  • the reflected wave is identified (step S8).
  • the evaluation target section is the propagation time of the bubble reflected wave when the ultrasonic wave is reflected at the deepest position of the measurement object from the propagation time of the bubble reflected wave when the ultrasonic wave is reflected at the shallowest position of the measurement target. It is the interval to.
  • the evaluation target section is obtained in advance by simulation or the like. Thereby, the bubble parameter specifying device 200 can exclude the reflected wave at the ship bottom B from the bubble reflected wave extracted by the bubble reflected wave extracting unit 204.
  • the amplitude specifying unit 207 specifies the amplitude related to the peak of the bubble reflected wave specified by the in-target bubble specifying unit 206 (step S9).
  • the amplitude normalization unit 208 normalizes the amplitude specified by the amplitude specifying unit 207 based on the propagation time (step S10). Specifically, the amplitude normalization unit 208 performs amplitude normalization according to the following procedure. First, the amplitude normalization unit 208 calculates the bubble depth as the target depth by multiplying the propagation time specified by the propagation time specifying unit 205 by the propagation speed of the ultrasonic wave and obtaining a half value thereof. To do.
  • the amplitude normalization unit 208 identifies the bubble depth stored in the histogram storage unit 210 that is closest to the calculated depth as the reference depth.
  • the amplitude normalization unit 208 calculates the attenuation rate of the ultrasonic wave between the reference depth and the target depth.
  • the amplitude normalization unit 208 normalizes the amplitude by multiplying the amplitude of the bubble reflected wave by the attenuation rate. As a result, the amplitude normalization unit 208 can align the reflection positions of the plurality of bubble reflected waves to the reference depth.
  • step S11 the number-of-extraction-information generating unit 209 calculates a normalized amplitude and a bubble reflected wave having the amplitude related to the selected reference depth among the bubble reflected waves normalized by the amplitude normalizing unit 208. A histogram showing the relationship with the number is generated (step S12).
  • the bubble parameter specifying unit 211 reads a histogram of each bubble diameter associated with the reference depth selected in step S11 from the histogram storage unit 210 (step S13).
  • the bubble parameter specifying unit 211 calculates a weighting factor for obtaining the histogram generated in step S12 based on the load sum of the histograms of the bubble diameters (step S14). That is, the bubble parameter specifying unit 211 obtains a weighting coefficient p that satisfies the following formula (1).
  • h is a vector indicating the histogram generated in step S12. That is, h is a column vector whose element is the number of bubble reflected waves for each amplitude.
  • G is a matrix indicating the histogram read in step S13. That is, G is a matrix having the amplitude as a row, the bubble diameter as a column, and the number of reflected bubbles as elements.
  • p is a column vector having a weighting factor for each bubble diameter as an element.
  • the bubble parameter specifying unit 211 can obtain the weighting coefficient p from Expression (1) by, for example, the least square method. Further, the bubble parameter specifying unit 211 may obtain the weighting coefficient p using an inverse matrix or a pseudo inverse matrix of the matrix G.
  • the bubble parameter specifying unit 211 specifies the weighting coefficient p so that the weighted sum of the number of bubbles for each amplitude indicated by the histogram read out in step S13 approximates the histogram generated in step S12.
  • the bubble parameter specifying unit 211 calculates the presence ratio of bubbles related to each bubble diameter in the measurement target from the specified weight coefficient p (step S15).
  • the bubble parameter specifying unit 211 specifies the relationship between the bubble diameter and the number of bubbles related to the bubble diameter by multiplying each specified existence ratio by the total number of bubble reflected waves related to the reference depth ( Step S16).
  • the void ratio specifying unit 212 determines the void ratio in the vicinity of the reference depth selected in step S11 based on the relationship between the bubble diameter specified by the bubble parameter specifying unit 211 and the number of bubbles related to the bubble diameter. Is calculated (step S17).
  • the void ratio V can be obtained by the following equation (2).
  • Nc is a volume in a predetermined range including the reference depth among the measurement objects.
  • a j is the j-th bubble diameter.
  • n j is the number of bubbles related to the j-th bubble diameter included in a predetermined range including the reference depth among the measurement objects.
  • q is the number of times ultrasonic waves are transmitted.
  • the bubble parameter specifying device 200 can specify the spatial distribution of the void ratio related to the measurement target by executing the processing from step S12 to step S17 for each reference depth.
  • the spatial distribution of the void ratio is information indicating the relationship between the depth from the ship bottom B and the void ratio in water at the depth.
  • the bubble parameter specifying system 1 determines the number and voids of bubbles included in the measurement target for each bubble diameter based on the amplitude and appearance rate of the bubble reflected wave for each bubble diameter. Identify rates. Thereby, the bubble parameter specifying device can accurately specify the relationship between the bubble diameter and the number of bubbles related to the bubble diameter and the void ratio in view of the variation in the intensity of the bubble reflected wave.
  • the bubble parameter specifying device 200 specifies the propagation time for each of the extracted bubble reflected waves. Thereby, the bubble parameter specifying unit 211 can specify the depth of the bubble reflected by the bubble reflected wave. According to the first embodiment of the present invention, the bubble parameter specifying device 200 specifies a bubble reflected wave reflected from a bubble included in the measurement target based on the propagation time. Thereby, the bubble parameter specifying device 200 can exclude bubbles that are not to be measured from the reflected wave.
  • the bubble parameter specifying device 200 normalizes the amplitude of each of the plurality of bubble reflected waves based on the corresponding propagation time. Thereby, the bubble parameter specifying device 200 can accurately specify the relationship between the bubble diameter and the number of bubbles related to the bubble diameter and the void ratio regardless of the attenuation according to the depth of the bubble.
  • the ultrasonic wave is transmitted as a longitudinal wave through the steel plate, and the transverse wave refraction angle ⁇ in the ultrasonic steel plate is not less than 40 degrees and not more than 45 degrees.
  • the transverse wave refraction angle ⁇ is 40 degrees or more, the longitudinal wave component is not included in the reflected wave.
  • the probe body 101 so that the transverse wave refraction angle ⁇ is 45 degrees or less, it is possible to prevent a decrease in the amount of transmitted acoustic energy into water.
  • the bubble parameter specifying device 200 specifies the number of bubbles included in the measurement target for each bubble diameter as the parameter related to the bubbles included in the measurement target, but is not limited thereto. .
  • the bubble parameter specifying device 200 calculates the bubble diameter appearance rate, the bubble volume, or other parameters of the bubbles included in the measurement target as the parameters related to the bubbles included in the measurement target. May be.
  • the bubble parameter specifying device 200 does not necessarily calculate the void ratio.
  • the bubble parameter specifying device 200 specifies the propagation time of the bubble reflected wave, but is not limited thereto.
  • the bubble parameter specifying device 200 may specify a parameter related to a bubble without performing correction based on the propagation time.
  • the histogram storage unit 210 stores a histogram indicating the relationship between the bubble reflected wave amplitude and the number of bubble reflected waves in association with the bubble diameter, but is not limited thereto. Absent.
  • the histogram storage unit 210 may store a table or function that records the appearance probability for each amplitude of the bubble reflected wave.
  • the void ratio specifying unit 212 calculates the void ratio for each depth of the measurement target, but is not limited thereto.
  • the void ratio specifying unit 212 may specify the void ratio of the entire measurement target.
  • the void ratio specifying unit 212 calculates the relationship between the bubble diameter and the number of bubbles in the entire measurement target by the bubble parameter specifying unit 211 adding the relationship between the bubble diameter and the number of bubbles related to each reference depth.
  • the void ratio of the whole measurement object can be specified by applying the said relationship to Formula (2).
  • the bubble parameter specifying device 200 specifies the void ratio of the entire measurement target by normalizing the measurement target to a certain depth without dividing the measurement target for each depth. May be.
  • the ultrasonic probe 100 transmits an ultrasonic wave as a transmission wave.
  • the present invention is not limited to this.
  • the probe may transmit a sound wave as a transmission wave.
  • FIG. 5 is a schematic block diagram illustrating a configuration of a computer according to at least one embodiment.
  • the computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input / output interface 904, and a communication interface 905.
  • the above-described bubble parameter specifying device 200 is mounted on the computer 900.
  • the operation of each processing unit described above is stored in the auxiliary storage device 903 in the form of a program.
  • the CPU 901 reads a program from the auxiliary storage device 903, develops it in the main storage device 902, and executes the above processing according to the program. Further, the CPU 901 secures a storage area corresponding to each of the above-described storage units in the main storage device 902 according to the program.
  • the auxiliary storage device 903 is an example of a tangible medium that is not temporary.
  • Other examples of the non-transitory tangible medium include an external storage 910 connected via the input / output interface 904 and a server 920 connected via the network N.
  • Examples of the external storage 910 include a magnetic disk, a magneto-optical disk, a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), and a semiconductor memory.
  • the program is distributed from the server 920 to the computer 900 via the network N, the computer 900 that has received the distribution may develop the program in the main storage device 902 and execute the above processing.
  • the program may be for realizing a part of the functions described above. Further, the program may be a difference file (difference program) that realizes the above-described function in combination with another program already stored in the auxiliary storage device 903.
  • difference file difference program
  • the probe control unit 201, the reflected wave recording unit 202, the reflected wave storage unit 203, the bubble reflected wave extraction unit 204, the propagation time specifying unit 205, the in-target bubble specifying unit 206, the amplitude specifying Unit 207, amplitude normalization unit 208, extraction number information generation unit 209, histogram storage unit 210, bubble parameter identification unit 211, void ratio identification unit 212 are provided in server 920, and the execution result is stored in computer 900. It may be delivered. That is, the bubble parameter specifying system 1 may be realized by a cloud computing system or a grid computing system.
  • the bubble parameter identification device can identify a parameter related to bubbles in view of variations in the intensity of the bubble reflected wave.
  • Bubble parameter specific system 100 Ultrasonic probe 200 Bubble parameter specific device 201 Probe control part 202 Reflected wave recording part 203 Reflected wave memory

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Abstract

A reflected wave receiving unit receives a reflected wave of a transmitted wave transmitted toward an object to be measured. A bubble reflected wave extracting unit extracts from the received reflected wave a bubble reflected wave, which is a reflected wave reflected from bubbles contained in the object being measured. An amplitude identifying unit identifies the amplitude of the extracted bubble reflected wave. An extracted number information generating unit generates extracted number information indicating a relationship between the amplitudes of a plurality of bubble reflected waves and the number of extracted bubble reflected waves. On the basis of appearance rate information indicating a relationship between the amplitude and the appearance rate of bubble reflected waves observed when bubbles having a certain bubble diameter are irradiated with a transmitted wave, said appearance rate information having been obtained in advance for each bubble diameter, and also on the basis of an identified appearance proportion, a bubble parameter identifying unit identifies the number of bubbles contained in the measurement object, for each bubble diameter.

Description

気泡パラメータ特定装置、気泡パラメータ特定方法、およびプログラムBubble parameter identification device, bubble parameter identification method, and program
　本発明は、計測対象に含まれる気泡に関するパラメータを特定する気泡パラメータ特定装置、気泡パラメータ特定方法、およびプログラムに関する。
　本願は、２０１６年０２月１８日に日本に出願された特願２０１６－０２８９５２号について優先権を主張し、その内容をここに援用する。 The present invention relates to a bubble parameter specifying device, a bubble parameter specifying method, and a program that specify parameters related to bubbles included in a measurement target.
This application claims priority on Japanese Patent Application No. 2016-028952 filed in Japan on February 18, 2016, the contents of which are incorporated herein by reference.
　特許文献１には、水中に含まれる気泡の量および水中のボイド率を求める方法が開示されている。具体的には、特許文献１には、水中に超音波を照射し、その反射波に基づいて気泡の量および径を求めることが開示されている。 Patent Document 1 discloses a method for obtaining the amount of bubbles contained in water and the void ratio in water. Specifically, Patent Document 1 discloses irradiating ultrasonic waves into water and obtaining the amount and diameter of bubbles based on the reflected waves.
特開２０１０－２１６８７２号公報JP 2010-216872 A
　気泡を含む水中に照射された超音波の反射波の強度は、照射された超音波の強度と、気泡の径に応じた反射係数とに基づいて求めることができる。他方、超音波の強度は、超音波ビームの中央付近と端部付近とで異なるため、超音波ビームに対する気泡の位置によって、受信される反射波の強度にばらつきが生じる。具体的には、気泡の位置が超音波ビームの中央から離れるほど、当該気泡による反射波の強度は相対的に小さくなる。そのため、特許文献１に記載の方法では、算出される気泡の径が正確でないため、当該気泡の径に基づいて算出されるボイド率も、精度に欠ける可能性がある。 The intensity of the reflected wave of the ultrasonic wave irradiated into the water containing bubbles can be obtained based on the intensity of the irradiated ultrasonic wave and the reflection coefficient according to the bubble diameter. On the other hand, since the intensity of the ultrasonic wave is different near the center and near the end of the ultrasonic beam, the intensity of the reflected wave received varies depending on the position of the bubble with respect to the ultrasonic beam. Specifically, the intensity of the reflected wave by the bubble becomes relatively smaller as the position of the bubble is further away from the center of the ultrasonic beam. For this reason, in the method described in Patent Document 1, since the calculated bubble diameter is not accurate, the void ratio calculated based on the bubble diameter may be inaccurate.
　本発明の目的は、計測対象に含まれる気泡に関するパラメータを精度よく特定することができる気泡パラメータ特定装置、気泡パラメータ特定方法、およびプログラムを提供することにある。 An object of the present invention is to provide a bubble parameter identification device, a bubble parameter identification method, and a program capable of accurately identifying parameters relating to bubbles included in a measurement target.
　本発明の第１の態様によれば、気泡パラメータ特定装置は、計測対象に含まれる気泡に関するパラメータを特定する気泡パラメータ特定装置であって、前記計測対象へ向けて発信された送信波の反射波を受信する反射波受信部と、受信した前記反射波から、前記計測対象に含まれる気泡によって反射された反射波である気泡反射波を抽出する気泡反射波抽出部と、抽出された前記気泡反射波の振幅を特定する振幅特定部と、前記複数の気泡反射波の振幅と抽出数との関係を示す抽出数情報を生成する抽出数情報生成部と、気泡径ごとに予め得られた、当該気泡径を有する気泡に送信波を照射した場合に観測される気泡反射波の振幅と出現率との関係を示す出現率情報と、特定された前記出現割合とに基づいて、前記計測対象に含まれる気泡の気泡径ごとの個数を特定する気泡パラメータ特定部とを備える。 According to the first aspect of the present invention, the bubble parameter specifying device is a bubble parameter specifying device that specifies a parameter relating to a bubble included in a measurement target, and is a reflected wave of a transmission wave transmitted toward the measurement target. A reflected wave receiving unit that extracts a bubble reflected wave that is a reflected wave reflected by a bubble included in the measurement object from the received reflected wave, and the extracted bubble reflection An amplitude identification unit that identifies the amplitude of the wave, an extraction number information generation unit that generates extraction number information indicating the relationship between the amplitude of the plurality of bubble reflected waves and the number of extractions, Included in the measurement object based on the appearance rate information indicating the relationship between the amplitude and the appearance rate of the bubble reflected wave observed when the transmission wave is irradiated to the bubble having the bubble diameter, and the specified appearance rate Bubbles And a bubble parameter specifying unit for specifying the number of each cell diameter.
　本発明の第２の態様によれば、第１の態様に係る気泡パラメータ特定装置は、抽出された前記気泡反射波それぞれについて、前記送信波の照射時刻から前記気泡反射波の受信時刻までの時間である伝播時間を特定する伝播時間特定部をさらに備えるものであってよい。 According to the second aspect of the present invention, the bubble parameter specifying device according to the first aspect is the time from the irradiation time of the transmission wave to the reception time of the bubble reflection wave for each of the extracted bubble reflection waves. It may further include a propagation time specifying unit for specifying the propagation time.
　本発明の第３の態様によれば、第２の態様に係る気泡パラメータ特定装置は、前記伝播時間に基づいて、前記気泡反射波のうち前記計測対象に含まれる気泡に反射したものを特定する対象内気泡特定部をさらに備え、前記抽出数情報生成部が、前記対象内気泡特定部によって特定された前記気泡反射波の振幅と抽出数との関係を示す抽出数情報を特定するものであってよい。 According to the third aspect of the present invention, the bubble parameter specifying device according to the second aspect specifies the reflected bubble reflected from the bubble included in the measurement target based on the propagation time. The extraction number information generation unit further includes extraction number information indicating a relationship between the amplitude of the bubble reflected wave specified by the in-target bubble specification unit and the extraction number. It's okay.
　本発明の第４の態様によれば、第２または第３の態様に係る気泡パラメータ特定装置は、前記振幅特定部が特定した前記複数の気泡反射波それぞれの振幅を、対応する前記伝播時間に基づいて正規化する振幅正規化部をさらに備えるものであってよい。 According to the fourth aspect of the present invention, in the bubble parameter specifying device according to the second or third aspect, the amplitude of each of the plurality of bubble reflected waves specified by the amplitude specifying unit is set to the corresponding propagation time. An amplitude normalization unit that normalizes based on the amplitude may be further provided.
　本発明の第５の態様によれば、第１から第４の何れかの態様に係る気泡パラメータ特定装置は、前記気泡パラメータ特定部が、前記出現率情報が示す振幅ごとの出現率の加重和が前記抽出数情報が示す振幅ごとの抽出数と近似するように、前記加重和の算出に用いる振幅ごとの重み係数を特定するものであってよい。 According to the fifth aspect of the present invention, in the bubble parameter identification device according to any one of the first to fourth aspects, the bubble parameter identification unit includes a weighted sum of appearance rates for each amplitude indicated by the appearance rate information. The weight coefficient for each amplitude used for the calculation of the weighted sum may be specified so as to approximate the number of extraction for each amplitude indicated by the extraction number information.
　本発明の第６の態様によれば、第５の態様に係る気泡パラメータ特定装置は、前記気泡パラメータ特定部が、前記振幅ごとの重み係数に前記気泡反射波の総抽出数を乗算することで、前記計測対象に含まれる気泡の気泡径ごとの個数を特定するものであってよい。 According to a sixth aspect of the present invention, in the bubble parameter specifying device according to the fifth aspect, the bubble parameter specifying unit multiplies the weight coefficient for each amplitude by the total number of extractions of the bubble reflected waves. The number of bubbles included in the measurement object for each bubble diameter may be specified.
　本発明の第７の態様によれば、第１から第６の何れかの態様に係る気泡パラメータ特定装置は、前記気泡パラメータ特定部が特定した前記計測対象に含まれる気泡の気泡径ごとの個数とに基づいて、前記計測対象のボイド率を特定するボイド率特定部をさらに備えるものであってよい。 According to the seventh aspect of the present invention, the bubble parameter specifying device according to any one of the first to sixth aspects is the number of bubbles included in the measurement target specified by the bubble parameter specifying unit for each bubble diameter. And a void ratio specifying unit that specifies the void ratio of the measurement target.
　本発明の第８の態様によれば、第１から第７の何れかの態様に係る気泡パラメータ特定装置は、前記反射波の包絡線を特定する包絡線処理部をさらに備え、前記気泡反射波抽出部が、前記包絡線のピークに基づいて、前記複数の気泡反射波を抽出するものであってよい。 According to an eighth aspect of the present invention, the bubble parameter specifying device according to any one of the first to seventh aspects further includes an envelope processing unit that specifies an envelope of the reflected wave, and the bubble reflected wave The extraction unit may extract the plurality of bubble reflected waves based on the peak of the envelope.
　本発明の第９の態様によれば、第８の態様に係る気泡パラメータ特定装置は、前記振幅特定部が、前記包絡線のピークの振幅に基づいて前記振幅を特定するものであってよい。 According to the ninth aspect of the present invention, in the bubble parameter specifying device according to the eighth aspect, the amplitude specifying unit may specify the amplitude based on an amplitude of a peak of the envelope.
　本発明の第１０の態様によれば、第１から第９の何れかの態様に係る気泡パラメータ特定装置は、前記気泡パラメータ特定部が、深さが異なる複数の前記計測対象からなる本計測対象に含まれる気泡の気泡径ごとの個数を、各深さの前記計測対象に含まれる前記気泡の気泡径ごとの個数の和を求めることで特定するものであってよい。 According to a tenth aspect of the present invention, in the bubble parameter identification device according to any one of the first to ninth aspects, the bubble parameter identification unit includes the plurality of measurement objects having different depths. The number of bubbles contained in each bubble diameter may be specified by obtaining the sum of the number of bubbles contained in the measurement target at each depth.
　本発明の第１１の態様によれば、第１０の態様に係る気泡パラメータ特定装置は、前記気泡パラメータ特定部が、深さごとに予め得られた前記出現率情報に基づいて、各深さの前記計測対象に含まれる前記気泡の気泡径ごとの個数の和を求めることで特定するものであってよい。 According to an eleventh aspect of the present invention, in the bubble parameter specifying device according to the tenth aspect, the bubble parameter specifying unit is configured so that each of the depths is based on the appearance rate information obtained in advance for each depth. You may specify by calculating | requiring the sum of the number for every bubble diameter of the said bubble contained in the said measurement object.
　本発明の第１２の態様によれば、第１から第１１の何れかの態様に係る気泡パラメータ特定装置は、前記送信波が縦波として鋼板を介して発信され、前記送信波の前記鋼板中の横波屈折角が４０度以上４５度以下であるものであってよい。 According to a twelfth aspect of the present invention, in the bubble parameter specifying device according to any one of the first to eleventh aspects, the transmission wave is transmitted as a longitudinal wave through a steel plate, and the transmission wave is in the steel plate. The transverse wave refraction angle may be 40 degrees or more and 45 degrees or less.
　本発明の第１３の態様によれば、気泡パラメータ特定方法は、計測対象に含まれる気泡に関するパラメータを特定する気泡パラメータ特定方法であって、前記計測対象へ向けて発信された送信波の反射波を受信する反射波受信ステップと、前記反射波から、前記計測対象に含まれる気泡によって反射された反射波である複数の気泡反射波を抽出する気泡反射波抽出ステップと、抽出された前記複数の気泡反射波の振幅を特定する振幅ステップと、前記複数の気泡反射波の振幅と抽出数との関係を示す抽出数情報を生成する抽出数情報生成ステップと、複数の気泡径ごとに予め得られた、前記気泡径を有する気泡に送信波を照射した場合に観測される気泡反射波の振幅と出現率との関係を示す出現率情報と、特定された前記出現割合とに基づいて、前記計測対象に含まれる気泡の気泡径と個数との関係を特定する気泡パラメータ特定ステップとを備える。 According to a thirteenth aspect of the present invention, the bubble parameter specifying method is a bubble parameter specifying method for specifying a parameter relating to a bubble included in a measurement target, and a reflected wave of a transmission wave transmitted toward the measurement target A reflected wave receiving step for extracting a plurality of bubble reflected waves that are reflected waves reflected by the bubbles included in the measurement object from the reflected wave, and a plurality of the extracted bubble reflected waves An amplitude step for specifying the amplitude of the bubble reflection wave, an extraction number information generation step for generating extraction number information indicating the relationship between the amplitude of the plurality of bubble reflection waves and the extraction number, and a plurality of bubble diameters are obtained in advance. Further, based on the appearance rate information indicating the relationship between the amplitude and the appearance rate of the bubble reflected wave observed when the transmission wave is irradiated to the bubble having the bubble diameter, and the specified appearance rate. Te, and a bubble parameter specifying step of specifying a relationship between the bubble diameter and the number of bubbles contained in the measurement target.
　本発明の第１４の態様によれば、プログラムは、計測対象に含まれる気泡に関するパラメータを特定する気泡パラメータ特定装置のコンピュータを、前記計測対象へ向けて発信された送信波の反射波を受信する反射波受信部、前記反射波から、前記計測対象に含まれる気泡によって反射された反射波である複数の気泡反射波を抽出する気泡反射波抽出部、抽出された前記複数の気泡反射波の振幅を特定する振幅特定部、前記複数の気泡反射波の振幅と抽出数との関係を示す抽出数情報を生成する抽出数情報生成部、複数の気泡径ごとに予め得られた、前記気泡径を有する気泡に送信波を照射した場合に観測される気泡反射波の振幅と出現率との関係を示す出現率情報と、特定された前記出現割合とに基づいて、前記計測対象に含まれる気泡の気泡径と個数との関係を特定する気泡パラメータ特定部として機能させる。 According to the fourteenth aspect of the present invention, the program receives the reflected wave of the transmission wave transmitted to the measurement target by the computer of the bubble parameter specifying device that specifies the parameter relating to the bubble included in the measurement target. A reflected wave receiving unit, a bubble reflected wave extracting unit that extracts a plurality of bubble reflected waves, which are reflected waves reflected by bubbles included in the measurement object, from the reflected wave, and amplitudes of the extracted bubble reflected waves An amplitude identification unit that identifies the number of extractions, and an extraction number information generation unit that generates extraction number information indicating the relationship between the amplitudes of the plurality of bubble reflected waves and the number of extractions. The bubbles included in the measurement object based on the appearance rate information indicating the relationship between the amplitude and the appearance rate of the bubble reflected wave observed when the transmission wave is irradiated to the bubbles having the air bubble and the specified appearance rate To function as a bubble parameter specifying unit for specifying a relationship between the bubble diameter to the number.
　上記態様のうち少なくとも１つの態様によれば、気泡パラメータ特定装置は、気泡径ごとの気泡反射波の振幅と出現率に基づいて、計測対象に含まれる気泡の気泡径ごとの個数を特定する。これにより、気泡パラメータ特定装置は、気泡反射波の強度のばらつきを鑑みて、気泡に関するパラメータを特定することができる。 According to at least one of the above aspects, the bubble parameter specifying device specifies the number of bubbles included in the measurement target for each bubble diameter based on the amplitude and appearance rate of the bubble reflected wave for each bubble diameter. Thereby, the bubble parameter specifying device can specify the parameter regarding the bubble in view of the variation in the intensity of the bubble reflected wave.
第１の実施形態に係る気泡パラメータ特定システムの構成を示す図である。It is a figure which shows the structure of the bubble parameter specific system which concerns on 1st Embodiment. 超音波の鋼中屈折角と、気泡反射波のエコーレベルとの関係を示す図である。It is a figure which shows the relationship between the refraction angle of an ultrasonic wave in steel, and the echo level of a bubble reflected wave. 超音波の鋼中屈折角と、反射波全体に対する気泡反射波のエコー比との関係を示す図である。It is a figure which shows the relationship between the refraction angle of an ultrasonic wave in steel, and the echo ratio of the bubble reflected wave with respect to the whole reflected wave. 第１の実施形態に係るボイド率の算出処理を示すフローチャートである。It is a flowchart which shows the calculation process of the void ratio which concerns on 1st Embodiment. 少なくとも１つの実施形態に係るコンピュータの構成を示す概略ブロック図である。It is a schematic block diagram which shows the structure of the computer which concerns on at least 1 embodiment.
〈第１の実施形態〉
《全体構成》
　以下、図面を参照しながら第１の実施形態について詳しく説明する。
　図１は、第１の実施形態に係る気泡パラメータ特定システムの構成を示す図である。
　気泡パラメータ特定システム１は、船舶の船底Ｂ近傍の水中のボイド率を特定する。ボイド率とは、流体の単位体積あたりに含まれれる気泡の容積割合を示すパラメータである。つまり、第１の実施形態に係る気泡パラメータ特定システム１は、船底Ｂ近傍の水を計測対象とする。気泡パラメータ特定システム１は、超音波探触子１００と気泡パラメータ特定装置２００とを備える。
　超音波探触子１００は、船底Ｂに対して所定の角度を以て超音波を発信し、その超音波の反射波を受信する。
　気泡パラメータ特定装置２００は、超音波探触子１００で受信された反射波に基づいて、船底Ｂ近傍の水中のボイド率を特定する。 <First Embodiment>
"overall structure"
Hereinafter, the first embodiment will be described in detail with reference to the drawings.
FIG. 1 is a diagram illustrating a configuration of a bubble parameter specifying system according to the first embodiment.
The bubble parameter specifying system 1 specifies the void ratio in the water near the bottom B of the ship. The void ratio is a parameter indicating the volume ratio of bubbles contained per unit volume of fluid. That is, the bubble parameter specifying system 1 according to the first embodiment uses water near the ship bottom B as a measurement target. The bubble parameter specifying system 1 includes an ultrasonic probe 100 and a bubble parameter specifying device 200.
The ultrasonic probe 100 transmits an ultrasonic wave at a predetermined angle with respect to the ship bottom B and receives a reflected wave of the ultrasonic wave.
The bubble parameter specifying device 200 specifies the void ratio in the water near the bottom B based on the reflected wave received by the ultrasonic probe 100.
《超音波探触子の構成》
　超音波探触子１００は、船舶の船底Ｂに設置される。具体的には、超音波探触子１００は、縦波の超音波を発信し、また受信する探触子本体１０１と、船底Ｂに対する探触子本体１０１の角度を規定するスペーサ１０２とを備える。つまり、探触子本体１０１から発される超音波は、スペーサ１０２と船底Ｂとの境界面、船底Ｂと水との境界面、および水と気泡との境界面で反射される。以下、水と気泡との境界面で反射された反射波を気泡反射波という。そのため、探触子本体１０１は、このような多重反射の影響を抑え、かつ水中への音響エネルギーの透過量を増大させることができる適切な角度で取り付けられる。具体的には、船底Ｂが鋼板で構成され、板厚が１５ミリメートル以上３０ミリメートル以下である場合、船底Ｂにおける横波屈折角が４０度以上かつ４５度以下の範囲内の角度となるように、好ましくは横波屈折角が４０度となるように探触子本体１０１が設置されるとよい。 <Configuration of ultrasonic probe>
The ultrasonic probe 100 is installed on the bottom B of the ship. Specifically, the ultrasonic probe 100 includes a probe main body 101 that transmits and receives longitudinal ultrasonic waves, and a spacer 102 that defines an angle of the probe main body 101 with respect to the ship bottom B. . That is, the ultrasonic wave emitted from the probe body 101 is reflected on the boundary surface between the spacer 102 and the ship bottom B, the boundary surface between the ship bottom B and water, and the boundary surface between water and bubbles. Hereinafter, the reflected wave reflected at the boundary surface between water and bubbles is referred to as a bubble reflected wave. Therefore, the probe body 101 is attached at an appropriate angle that can suppress the influence of such multiple reflection and increase the amount of transmission of acoustic energy into water. Specifically, when the ship bottom B is made of a steel plate and the plate thickness is 15 mm or more and 30 mm or less, the transverse wave refraction angle at the ship bottom B is an angle within a range of 40 degrees or more and 45 degrees or less. The probe main body 101 is preferably installed so that the transverse wave refraction angle is 40 degrees.
　図２は、超音波の鋼中屈折角と、気泡反射波のエコーレベルとの関係を示す図である。図３は、超音波の鋼中屈折角と、反射波全体に対する気泡反射波のエコー比との関係を示す図である。
　図２および図３によれば、船底Ｂにおける横波屈折角度θが４０度の近傍において、気泡反射波のエコーレベルおよび反射波全体に対する気泡反射波のエコー比が最大となる。４０度は臨界角であるため、探触子本体１０１から船底への超音波伝搬時に縦波成分が発生しない。したがって、横波屈折角度θが４０度以上となるように探触子本体１０１を設置することで、反射波に縦波成分が含まれれなくなる。つまり、横波屈折角度θが４０度以上となるように探触子本体１０１を設置することで、多重反射の影響を抑えることができる。他方、横波屈折角度θを４５度を超えると、気泡反射波のエコーレベルは横波屈折角度θが４０度であるときに得られるエコーレベルの９０パーセント未満となる。つまり、横波屈折角度θが４５度以下となるように探触子本体１０１を設置することで、水中への音響エネルギーの透過量の減少を防ぐことができる。
　なお、本実施形態において、横波屈折角度θが４０度となる探触子本体１０１の取付角度φ（鉛直線に対する探触子本体１０１の超音波の発信面の垂線の角度）は、２８度である。 FIG. 2 is a graph showing the relationship between the refraction angle of ultrasonic waves in steel and the echo level of bubble reflected waves. FIG. 3 is a diagram showing the relationship between the refraction angle of the ultrasonic wave in steel and the echo ratio of the bubble reflected wave with respect to the entire reflected wave.
2 and 3, the echo level of the bubble reflected wave and the echo ratio of the bubble reflected wave with respect to the entire reflected wave are maximized when the transverse wave refraction angle θ at the bottom B is 40 degrees. Since 40 degrees is a critical angle, no longitudinal wave component is generated during ultrasonic propagation from the probe body 101 to the ship bottom. Therefore, the longitudinal wave component is not included in the reflected wave by installing the probe body 101 so that the transverse wave refraction angle θ is 40 degrees or more. That is, the influence of multiple reflection can be suppressed by installing the probe body 101 so that the transverse wave refraction angle θ is 40 degrees or more. On the other hand, when the transverse wave refraction angle θ exceeds 45 degrees, the echo level of the bubble reflected wave is less than 90% of the echo level obtained when the transverse wave refraction angle θ is 40 degrees. That is, by setting the probe body 101 so that the transverse wave refraction angle θ is 45 degrees or less, it is possible to prevent a decrease in the amount of transmission of acoustic energy into water.
In the present embodiment, the mounting angle φ of the probe main body 101 (the angle of the perpendicular of the ultrasonic wave transmitting surface of the probe main body 101 with respect to the vertical line) at which the transverse wave refraction angle θ is 40 degrees is 28 degrees. is there.
《気泡パラメータ特定装置の構成》
　気泡パラメータ特定装置２００は、探触子制御部２０１、反射波記録部２０２、反射波記憶部２０３、気泡反射波抽出部２０４、伝播時間特定部２０５、対象内気泡特定部２０６、振幅特定部２０７、振幅正規化部２０８、抽出数情報生成部２０９、ヒストグラム記憶部２１０、気泡パラメータ特定部２１１、ボイド率特定部２１２を備える。 <Configuration of bubble parameter identification device>
The bubble parameter specifying device 200 includes a probe control unit 201, a reflected wave recording unit 202, a reflected wave storage unit 203, a bubble reflected wave extraction unit 204, a propagation time specifying unit 205, an in-target bubble specifying unit 206, and an amplitude specifying unit 207. , An amplitude normalization unit 208, an extraction number information generation unit 209, a histogram storage unit 210, a bubble parameter specification unit 211, and a void rate specification unit 212.
　探触子制御部２０１は、超音波探触子１００に、超音波を発信指示を出力する。探触子制御部２０１は、超音波探触子１００が発信した超音波の反射波の波形を、超音波探触子１００から受信する。具体的には、探触子制御部２０１は、超音波探触子１００から出力されるアナログ信号を増幅してデジタル信号に変換する。探触子制御部２０１は、反射波受信部の一例である。
　反射波記録部２０２は、探触子制御部２０１が受信した反射波の波形を、超音波の発信時刻（照射時刻）に関連付けて反射波記憶部２０３に記録する。反射波の波形は、反射波の受信時刻とレベルとの関係により特定される。
　反射波記憶部２０３は、超音波の発信時刻ごとに、当該超音波の反射波を記憶する。 The probe control unit 201 outputs an instruction to transmit ultrasonic waves to the ultrasonic probe 100. The probe control unit 201 receives the waveform of the reflected wave of the ultrasonic wave transmitted from the ultrasonic probe 100 from the ultrasonic probe 100. Specifically, the probe control unit 201 amplifies the analog signal output from the ultrasonic probe 100 and converts it into a digital signal. The probe control unit 201 is an example of a reflected wave receiving unit.
The reflected wave recording unit 202 records the waveform of the reflected wave received by the probe control unit 201 in the reflected wave storage unit 203 in association with the transmission time (irradiation time) of the ultrasonic wave. The waveform of the reflected wave is specified by the relationship between the reception time of the reflected wave and the level.
The reflected wave storage unit 203 stores the reflected wave of the ultrasonic wave for each transmission time of the ultrasonic wave.
　気泡反射波抽出部２０４、気泡反射波抽出部２０４は、反射波記憶部２０３が記憶する反射波から、気泡反射波を抽出する。
　伝播時間特定部２０５は、気泡反射波抽出部２０４が抽出した気泡反射波に基づいて、超音波の発信時刻から気泡反射波の受信時刻までの時間である伝播時間を特定する。
　対象内気泡特定部２０６は、伝播時間特定部２０５が特定した伝播時間に基づいて、気泡パラメータの特定対象となる範囲内に存在する気泡を特定する。 The bubble reflected wave extraction unit 204 and the bubble reflected wave extraction unit 204 extract the bubble reflected wave from the reflected wave stored in the reflected wave storage unit 203.
Based on the bubble reflected wave extracted by the bubble reflected wave extracting unit 204, the propagation time identifying unit 205 identifies the propagation time that is the time from the transmission time of the ultrasonic wave to the reception time of the bubble reflected wave.
Based on the propagation time specified by the propagation time specifying unit 205, the in-target bubble specifying unit 206 specifies bubbles that exist within the range that is the target of specifying the bubble parameter.
　振幅特定部２０７は、気泡反射波抽出部２０４が抽出した気泡反射波の振幅を特定する。具体的には、振幅特定部２０７は、気泡反射波の包絡線の極大値を振幅として特定する。
　振幅正規化部２０８は、振幅特定部２０７が特定した振幅を伝播時間に応じて正規化する。超音波の反射波は、反射位置までの距離が長いほど減衰する。したがって、振幅正規化部２０８は、振幅を正規化することで、気泡の位置に応じた減衰の影響を低減することができる。
　抽出数情報生成部２０９は、気泡反射波の振幅範囲ごとの抽出数を示す抽出数情報を生成する。 The amplitude specifying unit 207 specifies the amplitude of the bubble reflected wave extracted by the bubble reflected wave extracting unit 204. Specifically, the amplitude specifying unit 207 specifies the maximum value of the envelope of the bubble reflected wave as the amplitude.
The amplitude normalization unit 208 normalizes the amplitude specified by the amplitude specification unit 207 according to the propagation time. The reflected ultrasonic wave is attenuated as the distance to the reflection position is longer. Therefore, the amplitude normalization unit 208 can reduce the influence of attenuation according to the position of the bubble by normalizing the amplitude.
The extraction number information generation unit 209 generates extraction number information indicating the extraction number for each amplitude range of the bubble reflected wave.
　ヒストグラム記憶部２１０は、気泡の直径と、気泡の深さとに関連付けて、当該気泡で反射した気泡反射波の振幅とその出現数との関係を示すヒストグラムを記憶する。当該ヒストグラムは、シミュレーションまたは実験により予め得られたものである。ここで「深さ」とは、探触子本体１０１の発信面の垂線方向の距離である。
　ここで、シミュレーションにより気泡反射波の振幅とその出現数との関係を示すヒストグラムを生成する方法の一例を説明する。作業者は、シミュレーションのモデルとして、船底Ｂと同じ厚さを有する鋼板の上に超音波探触子１００が設置され、水中に所定径の気泡が１つ存在するモデルを作成する。当該モデルにおける気泡の位置は、所定の深さにおける、超音波の照射面に平行な面上のランダムな位置に設けられる。次に、作業者は、シミュレータに当該モデルを用いて超音波探触子１００による音響シミュレーションを実行させる。これにより、シミュレータは、気泡反射波の波形を生成することができる。次に、作業者は、上記シミュレーションを複数回実行することで、所定深さの位置に存在する所定径の気泡について、当該気泡で反射した気泡反射波の振幅とその出現数との関係を示すヒストグラムを生成する。作業者は、上記手順によるヒストグラムの生成を、複数の径および複数の深さの気泡について実行する。これにより、作業者は、気泡の直径ごとおよび深さごとのヒストグラムを生成することができる。
　ヒストグラム記憶部２１０が記憶するヒストグラムは、気泡径ごとに予め得られた、当該気泡径を有する気泡に送信波を照射した場合に観測される気泡反射波の振幅と出現率との関係を示す出現率情報の一例である。 The histogram storage unit 210 stores a histogram indicating the relationship between the bubble reflected wave reflected by the bubble and the number of appearances in association with the bubble diameter and the bubble depth. The histogram is obtained in advance by simulation or experiment. Here, the “depth” is a distance in the direction perpendicular to the transmission surface of the probe main body 101.
Here, an example of a method for generating a histogram indicating the relationship between the amplitude of the bubble reflected wave and the number of appearances thereof by simulation will be described. As a simulation model, the operator creates a model in which the ultrasonic probe 100 is installed on a steel plate having the same thickness as the ship bottom B, and one bubble having a predetermined diameter exists in water. The positions of the bubbles in the model are provided at random positions on a plane parallel to the ultrasonic irradiation surface at a predetermined depth. Next, the worker causes the simulator to execute an acoustic simulation using the ultrasonic probe 100 using the model. Thereby, the simulator can generate | occur | produce the waveform of a bubble reflected wave. Next, the operator shows the relationship between the amplitude of the bubble reflected wave reflected by the bubble and the number of appearances of the bubble having a predetermined diameter existing at a predetermined depth by executing the simulation a plurality of times. Generate a histogram. The operator executes the generation of the histogram according to the above procedure for bubbles having a plurality of diameters and a plurality of depths. Thereby, the operator can generate | occur | produce the histogram for every diameter of a bubble, and every depth.
The histogram stored in the histogram storage unit 210 is an appearance indicating the relationship between the amplitude and the appearance rate of the bubble reflected wave, which is obtained in advance for each bubble diameter and observed when the transmission wave is irradiated to the bubble having the bubble diameter. It is an example of rate information.
　気泡パラメータ特定部２１１は、抽出数情報生成部２０９が生成した抽出数情報と、ヒストグラム記憶部２１０が記憶するヒストグラムとに基づいて、計測対象に含まれる気泡の径と数との関係を特定する。計測対象に含まれる気泡の径と数との関係は、気泡に関するパラメータの一例である。
　ボイド率特定部２１２は、気泡パラメータ特定部２１１が特定した気泡の径と数との関係に基づいて、計測対象のボイド率を算出する。 The bubble parameter specifying unit 211 specifies the relationship between the diameter and the number of bubbles included in the measurement target based on the extraction number information generated by the extraction number information generation unit 209 and the histogram stored in the histogram storage unit 210. . The relationship between the diameter and the number of bubbles included in the measurement target is an example of a parameter related to bubbles.
The void ratio specifying unit 212 calculates the void ratio to be measured based on the relationship between the diameter and the number of bubbles specified by the bubble parameter specifying unit 211.
　次に、第１の実施形態に係る気泡パラメータ特定システム１の動作について説明する。図４は、第１の実施形態に係るボイド率の算出処理を示すフローチャートである。
　気泡パラメータ特定システム１がボイド率の算出処理を開始すると、探触子制御部２０１は、超音波探触子１００に、超音波を発信指示を間欠的に複数回（例えば、数百回から数千回）出力する（ステップＳ１）。これにより、超音波探触子１００は、超音波の送信および反射波の受信を複数回実行する。次に、探触子制御部２０１は、超音波探触子１００から複数の反射波の波形を受信する（ステップＳ２）。反射波記録部２０２は、探触子制御部２０１が受信した反射波の波形を超音波の発信時刻に関連付けて反射波記憶部２０３に記録する（ステップＳ３）。 Next, the operation of the bubble parameter specifying system 1 according to the first embodiment will be described. FIG. 4 is a flowchart showing a void ratio calculation process according to the first embodiment.
When the bubble parameter specifying system 1 starts the void ratio calculation process, the probe control unit 201 intermittently sends an ultrasonic wave transmission instruction to the ultrasonic probe 100 a plurality of times (for example, several hundred to several times). 1000 times) (step S1). Thereby, the ultrasonic probe 100 executes transmission of ultrasonic waves and reception of reflected waves a plurality of times. Next, the probe control unit 201 receives a plurality of reflected wave waveforms from the ultrasonic probe 100 (step S2). The reflected wave recording unit 202 records the reflected wave waveform received by the probe control unit 201 in the reflected wave storage unit 203 in association with the transmission time of the ultrasonic wave (step S3).
　次に、気泡パラメータ特定装置２００は、反射波記憶部２０３が記憶する反射波の波形を１つずつ選択し、選択した各波形について以下に示すステップＳ５からステップＳ１０の処理を実行する（ステップＳ４）。
　気泡反射波抽出部２０４は、ステップＳ４で選択された反射波の波形に包絡線処理を実施する（ステップＳ５）。次に、気泡反射波抽出部２０４は、反射波の包絡線の各ピークを気泡反射波として抽出する（ステップＳ６）。次に、伝播時間特定部２０５は、ステップＳ４で選択された反射波に関連付けられた超音波の発信時刻と気泡反射波抽出部２０４が抽出した各気泡反射波の受信時刻とから、各気泡反射波の伝播時間（ＴＯＦ：Time Of Fright）を特定する（ステップＳ７）。次に、対象内気泡特定部２０６は、気泡反射波のうち、伝播時間特定部２０５が特定した伝播時間が所定の評価対象区間内に存在するものを、計測対象に含まれる気泡に反射した気泡反射波と特定する（ステップＳ８）。なお、評価対象区間とは、超音波が計測対象の最も浅い位置で反射する場合における気泡反射波の伝播時間から、超音波が計測対象の最も深い位置で反射する場合における気泡反射波の伝播時間までの区間である。評価対象区間は、予めシミュレーション等により求められる。これにより、気泡パラメータ特定装置２００は、気泡反射波抽出部２０４が抽出した気泡反射波から船底Ｂでの反射波を除外することができる。 Next, the bubble parameter specifying device 200 selects the reflected wave waveforms stored in the reflected wave storage unit 203 one by one, and executes the processing from step S5 to step S10 shown below for each selected waveform (step S4). ).
The bubble reflected wave extraction unit 204 performs envelope processing on the waveform of the reflected wave selected in step S4 (step S5). Next, the bubble reflected wave extraction unit 204 extracts each peak of the envelope of the reflected wave as a bubble reflected wave (step S6). Next, the propagation time specifying unit 205 determines each bubble reflection from the transmission time of the ultrasonic wave associated with the reflected wave selected in step S4 and the reception time of each bubble reflected wave extracted by the bubble reflected wave extraction unit 204. A wave propagation time (TOF: Time Of Fright) is specified (step S7). Next, the in-target bubble specifying unit 206 reflects a bubble reflected from the bubble included in the measurement target when the propagation time specified by the propagation time specifying unit 205 is present in the predetermined evaluation target section. The reflected wave is identified (step S8). Note that the evaluation target section is the propagation time of the bubble reflected wave when the ultrasonic wave is reflected at the deepest position of the measurement object from the propagation time of the bubble reflected wave when the ultrasonic wave is reflected at the shallowest position of the measurement target. It is the interval to. The evaluation target section is obtained in advance by simulation or the like. Thereby, the bubble parameter specifying device 200 can exclude the reflected wave at the ship bottom B from the bubble reflected wave extracted by the bubble reflected wave extracting unit 204.
　次に、振幅特定部２０７は、対象内気泡特定部２０６によって特定された気泡反射波のピークに係る振幅を特定する（ステップＳ９）。次に、振幅正規化部２０８は、振幅特定部２０７によって特定された振幅を、伝播時間に基づいて正規化する（ステップＳ１０）。具体的には、振幅正規化部２０８は、以下の手順で振幅の正規化を行う。まず振幅正規化部２０８は、伝播時間特定部２０５が特定した伝播時間に超音波の伝播速度を乗算し、その２分の１の値を求めることで、気泡の深さを対象深さとして算出する。次に、振幅正規化部２０８は、ヒストグラム記憶部２１０が記憶する気泡の深さのうち、算出された深さに最も近いものを基準深さとして特定する。次に、振幅正規化部２０８は、基準深さから対象深さまでの間における超音波の減衰率を算出する。次に、振幅正規化部２０８は、気泡反射波の振幅に当該減衰率を乗算することで、振幅の正規化を行う。これにより、振幅正規化部２０８は、複数の気泡反射波の反射位置を基準深さにそろえることができる。 Next, the amplitude specifying unit 207 specifies the amplitude related to the peak of the bubble reflected wave specified by the in-target bubble specifying unit 206 (step S9). Next, the amplitude normalization unit 208 normalizes the amplitude specified by the amplitude specifying unit 207 based on the propagation time (step S10). Specifically, the amplitude normalization unit 208 performs amplitude normalization according to the following procedure. First, the amplitude normalization unit 208 calculates the bubble depth as the target depth by multiplying the propagation time specified by the propagation time specifying unit 205 by the propagation speed of the ultrasonic wave and obtaining a half value thereof. To do. Next, the amplitude normalization unit 208 identifies the bubble depth stored in the histogram storage unit 210 that is closest to the calculated depth as the reference depth. Next, the amplitude normalization unit 208 calculates the attenuation rate of the ultrasonic wave between the reference depth and the target depth. Next, the amplitude normalization unit 208 normalizes the amplitude by multiplying the amplitude of the bubble reflected wave by the attenuation rate. As a result, the amplitude normalization unit 208 can align the reflection positions of the plurality of bubble reflected waves to the reference depth.
　気泡パラメータ特定装置２００は、反射波記憶部２０３が記憶するすべての反射波の波形から正規化された気泡反射波を抽出すると、基準深さを１つずつ選択し、各基準深さについて以下のステップＳ１２からステップＳ１７の処理を実行する（ステップＳ１１）。
　まず抽出数情報生成部２０９は、振幅正規化部２０８によって正規化された気泡反射波のうち、選択された基準深さに係るものについて、正規化された振幅と当該振幅を有する気泡反射波の数との関係を示すヒストグラムを生成する（ステップＳ１２）。次に、気泡パラメータ特定部２１１は、ヒストグラム記憶部２１０からステップＳ１１で選択された基準深さに関連付けられた各気泡径のヒストグラムを読み出す（ステップＳ１３）。次に、気泡パラメータ特定部２１１は、各気泡径のヒストグラムの荷重和によりステップＳ１２で生成したヒストグラムを得るための重み係数を算出する（ステップＳ１４）。つまり、気泡パラメータ特定部２１１は、以下の式（１）を満たす重み係数ｐを求める。 When the bubble parameter specifying device 200 extracts the normalized bubble reflected wave from the waveform of all the reflected waves stored in the reflected wave storage unit 203, the bubble parameter specifying device 200 selects the reference depth one by one. The processing from step S12 to step S17 is executed (step S11).
First, the number-of-extraction-information generating unit 209 calculates a normalized amplitude and a bubble reflected wave having the amplitude related to the selected reference depth among the bubble reflected waves normalized by the amplitude normalizing unit 208. A histogram showing the relationship with the number is generated (step S12). Next, the bubble parameter specifying unit 211 reads a histogram of each bubble diameter associated with the reference depth selected in step S11 from the histogram storage unit 210 (step S13). Next, the bubble parameter specifying unit 211 calculates a weighting factor for obtaining the histogram generated in step S12 based on the load sum of the histograms of the bubble diameters (step S14). That is, the bubble parameter specifying unit 211 obtains a weighting coefficient p that satisfies the following formula (1).
Figure JPOXMLDOC01-appb-M000001
Figure JPOXMLDOC01-appb-M000001
　ｈは、ステップＳ１２で生成したヒストグラムを示すベクトルである。つまり、ｈは、振幅ごとの気泡反射波の数を要素とする列ベクトルである。Ｇは、ステップＳ１３で読み出されたヒストグラムを示す行列である。つまり、Ｇは、振幅を行とし、気泡径を列とし、気泡反射波の数を要素とする行列である。ｐは、気泡径ごとの重み係数を要素とする列ベクトルである。気泡パラメータ特定部２１１は、例えば最小二乗法により式（１）から重み係数ｐを求めることができる。また、気泡パラメータ特定部２１１は、行列Ｇの逆行列または疑似逆行列を用いて重み係数ｐを求めてもよい。つまり、気泡パラメータ特定部２１１は、ステップＳ１３で読み出されたヒストグラムが示す振幅ごとの気泡の数の加重和がステップＳ１２で生成したヒストグラムと近似するように、重み係数ｐを特定する。
　次に、気泡パラメータ特定部２１１は、特定した重み係数ｐから、計測対象における各気泡径に係る気泡の存在割合を算出する（ステップＳ１５）。次に、気泡パラメータ特定部２１１は、特定した各存在割合を基準深さに係る気泡反射波の総数に乗算することで、気泡径と当該気泡径に係る気泡の数との関係を特定する（ステップＳ１６）。次に、ボイド率特定部２１２は、気泡パラメータ特定部２１１が特定した気泡径と当該気泡径に係る気泡の数との関係に基づいて、ステップＳ１１で選択された基準深さの近傍におけるボイド率を算出する（ステップＳ１７）。ボイド率Ｖは、以下に示す式（２）により求めることができる。 h is a vector indicating the histogram generated in step S12. That is, h is a column vector whose element is the number of bubble reflected waves for each amplitude. G is a matrix indicating the histogram read in step S13. That is, G is a matrix having the amplitude as a row, the bubble diameter as a column, and the number of reflected bubbles as elements. p is a column vector having a weighting factor for each bubble diameter as an element. The bubble parameter specifying unit 211 can obtain the weighting coefficient p from Expression (1) by, for example, the least square method. Further, the bubble parameter specifying unit 211 may obtain the weighting coefficient p using an inverse matrix or a pseudo inverse matrix of the matrix G. That is, the bubble parameter specifying unit 211 specifies the weighting coefficient p so that the weighted sum of the number of bubbles for each amplitude indicated by the histogram read out in step S13 approximates the histogram generated in step S12.
Next, the bubble parameter specifying unit 211 calculates the presence ratio of bubbles related to each bubble diameter in the measurement target from the specified weight coefficient p (step S15). Next, the bubble parameter specifying unit 211 specifies the relationship between the bubble diameter and the number of bubbles related to the bubble diameter by multiplying each specified existence ratio by the total number of bubble reflected waves related to the reference depth ( Step S16). Next, the void ratio specifying unit 212 determines the void ratio in the vicinity of the reference depth selected in step S11 based on the relationship between the bubble diameter specified by the bubble parameter specifying unit 211 and the number of bubbles related to the bubble diameter. Is calculated (step S17). The void ratio V can be obtained by the following equation (2).
Figure JPOXMLDOC01-appb-M000002
Figure JPOXMLDOC01-appb-M000002
　Ｎｃは、計測対象のうち基準深さを含む所定範囲の体積である。ａｊは、ｊ番目の気泡径である。ｎｊは、計測対象のうち基準深さを含む所定範囲に含まれるｊ番目の気泡径に係る気泡の個数である。ｑは、超音波の発信回数である。 Nc is a volume in a predetermined range including the reference depth among the measurement objects. a j is the j-th bubble diameter. n j is the number of bubbles related to the j-th bubble diameter included in a predetermined range including the reference depth among the measurement objects. q is the number of times ultrasonic waves are transmitted.
　気泡パラメータ特定装置２００は、各基準深さについて上記ステップＳ１２からステップＳ１７の処理を実行することで、計測対象に係るボイド率の空間分布を特定することができる。ボイド率の空間分布とは、船底Ｂからの深さと当該深さにおける水中のボイド率との関係を示す情報である。 The bubble parameter specifying device 200 can specify the spatial distribution of the void ratio related to the measurement target by executing the processing from step S12 to step S17 for each reference depth. The spatial distribution of the void ratio is information indicating the relationship between the depth from the ship bottom B and the void ratio in water at the depth.
　このように、第１の実施形態によれば、気泡パラメータ特定システム１は、気泡径ごとの気泡反射波の振幅と出現率に基づいて、計測対象に含まれる気泡の気泡径ごとの個数およびボイド率を特定する。これにより、気泡パラメータ特定装置は、気泡反射波の強度のばらつきを鑑みて、精度よく気泡径と当該気泡径に係る気泡の数との関係およびボイド率を特定することができる。 As described above, according to the first embodiment, the bubble parameter specifying system 1 determines the number and voids of bubbles included in the measurement target for each bubble diameter based on the amplitude and appearance rate of the bubble reflected wave for each bubble diameter. Identify rates. Thereby, the bubble parameter specifying device can accurately specify the relationship between the bubble diameter and the number of bubbles related to the bubble diameter and the void ratio in view of the variation in the intensity of the bubble reflected wave.
　また、第１の実施形態によれば、気泡パラメータ特定装置２００は、抽出された前記気泡反射波それぞれについて伝播時間を特定する。これにより、気泡パラメータ特定部２１１は、気泡反射波が反射した気泡の深さを特定することができる。本発明の第１の実施形態によれば、気泡パラメータ特定装置２００は、伝播時間に基づいて気泡反射波のうち計測対象に含まれる気泡に反射したものを特定する。これにより、気泡パラメータ特定装置２００は、反射波から計測対象外の気泡を除外することができる。 Further, according to the first embodiment, the bubble parameter specifying device 200 specifies the propagation time for each of the extracted bubble reflected waves. Thereby, the bubble parameter specifying unit 211 can specify the depth of the bubble reflected by the bubble reflected wave. According to the first embodiment of the present invention, the bubble parameter specifying device 200 specifies a bubble reflected wave reflected from a bubble included in the measurement target based on the propagation time. Thereby, the bubble parameter specifying device 200 can exclude bubbles that are not to be measured from the reflected wave.
　また、第１の実施形態によれば、気泡パラメータ特定装置２００は、複数の気泡反射波それぞれの振幅を、対応する伝播時間に基づいて正規化する。これにより、気泡パラメータ特定装置２００は、気泡の深さに応じた減衰によらず、正確に気泡径と当該気泡径に係る気泡の数との関係およびボイド率を特定することができる。 In addition, according to the first embodiment, the bubble parameter specifying device 200 normalizes the amplitude of each of the plurality of bubble reflected waves based on the corresponding propagation time. Thereby, the bubble parameter specifying device 200 can accurately specify the relationship between the bubble diameter and the number of bubbles related to the bubble diameter and the void ratio regardless of the attenuation according to the depth of the bubble.
　また、第１の実施形態によれば、超音波は、縦波として鋼板を介して発信され、超音波の鋼板中の横波屈折角度θが４０度以上４５度以下である。横波屈折角度θが４０度以上となるように探触子本体１０１を設置することで、反射波に縦波成分が含まれれなくなる。また、横波屈折角度θが４５度以下となるように探触子本体１０１を設置することで、水中への音響エネルギーの透過量の減少を防ぐことができる。 Also, according to the first embodiment, the ultrasonic wave is transmitted as a longitudinal wave through the steel plate, and the transverse wave refraction angle θ in the ultrasonic steel plate is not less than 40 degrees and not more than 45 degrees. By installing the probe body 101 so that the transverse wave refraction angle θ is 40 degrees or more, the longitudinal wave component is not included in the reflected wave. Further, by installing the probe body 101 so that the transverse wave refraction angle θ is 45 degrees or less, it is possible to prevent a decrease in the amount of transmitted acoustic energy into water.
　以上、図面を参照して第１の実施形態について詳しく説明してきたが、具体的な構成は上述のものに限られることはなく、様々な設計変更等をすることが可能である。
　例えば、第１の実施形態によれば、気泡パラメータ特定装置２００は、計測対象に含まれる気泡に関するパラメータとして、計測対象に含まれる気泡の気泡径ごとの個数を特定するが、これに限られない。例えば、他の実施形態においては、気泡パラメータ特定装置２００は、計測対象に含まれる気泡に関するパラメータとして、計測対象に含まれる気泡の気泡径の出現率、気泡の体積、またはその他のパラメータを算出してもよい。また、他の実施形態に係る気泡パラメータ特定装置２００は、必ずしもボイド率を算出しなくてよい。 As described above, the first embodiment has been described in detail with reference to the drawings. However, the specific configuration is not limited to the above, and various design changes and the like can be made.
For example, according to the first embodiment, the bubble parameter specifying device 200 specifies the number of bubbles included in the measurement target for each bubble diameter as the parameter related to the bubbles included in the measurement target, but is not limited thereto. . For example, in another embodiment, the bubble parameter specifying device 200 calculates the bubble diameter appearance rate, the bubble volume, or other parameters of the bubbles included in the measurement target as the parameters related to the bubbles included in the measurement target. May be. In addition, the bubble parameter specifying device 200 according to another embodiment does not necessarily calculate the void ratio.
　また、第１の実施形態によれば、気泡パラメータ特定装置２００は、気泡反射波の伝播時間を特定するが、これに限られない。例えば、他の実施形態においては、気泡パラメータ特定装置２００は、伝播時間に基づく補正等を行うことなく気泡に関するパラメータを特定してもよい。 Further, according to the first embodiment, the bubble parameter specifying device 200 specifies the propagation time of the bubble reflected wave, but is not limited thereto. For example, in another embodiment, the bubble parameter specifying device 200 may specify a parameter related to a bubble without performing correction based on the propagation time.
　また、第１の実施形態によれば、ヒストグラム記憶部２１０は、気泡径に関連付けて、気泡反射波の振幅と当該気泡反射波の数との関係を示すヒストグラムを記憶するが、これに限られない。例えば、他の実施形態においては、ヒストグラム記憶部２１０は、気泡反射波の振幅ごとの出現確率を記録したテーブルまたは関数を記憶してもよい。 Further, according to the first embodiment, the histogram storage unit 210 stores a histogram indicating the relationship between the bubble reflected wave amplitude and the number of bubble reflected waves in association with the bubble diameter, but is not limited thereto. Absent. For example, in another embodiment, the histogram storage unit 210 may store a table or function that records the appearance probability for each amplitude of the bubble reflected wave.
　また、第１の実施形態によれば、ボイド率特定部２１２は、計測対象の深さごとのボイド率を算出したが、これに限られない。例えば、他の実施形態においては、ボイド率特定部２１２は、計測対象全体のボイド率を特定しても良い。具体的には、ボイド率特定部２１２は、気泡パラメータ特定部２１１が各基準深さに係る気泡径と気泡数の関係を加算することで、計測対象全体における気泡径と気泡数の関係を算出し、当該関係を式（２）に適用することにより計測対象全体のボイド率を特定することができる。また、他の実施形態においては、気泡パラメータ特定装置２００は、計測対象を深さごとに区切らず、計測対象全体について一定深さに正規化を行うことで、計測対象全体のボイド率を特定してもよい。 Further, according to the first embodiment, the void ratio specifying unit 212 calculates the void ratio for each depth of the measurement target, but is not limited thereto. For example, in another embodiment, the void ratio specifying unit 212 may specify the void ratio of the entire measurement target. Specifically, the void ratio specifying unit 212 calculates the relationship between the bubble diameter and the number of bubbles in the entire measurement target by the bubble parameter specifying unit 211 adding the relationship between the bubble diameter and the number of bubbles related to each reference depth. And the void ratio of the whole measurement object can be specified by applying the said relationship to Formula (2). In another embodiment, the bubble parameter specifying device 200 specifies the void ratio of the entire measurement target by normalizing the measurement target to a certain depth without dividing the measurement target for each depth. May be.
　また、第１の実施形態では、超音波探触子１００が送信波として超音波を発信する場合について説明したが、これに限られない。例えば、他の実施形態では、探触子は送信波として音波を発信してもよい。 In the first embodiment, the case where the ultrasonic probe 100 transmits an ultrasonic wave as a transmission wave has been described. However, the present invention is not limited to this. For example, in another embodiment, the probe may transmit a sound wave as a transmission wave.
　図５は、少なくとも１つの実施形態に係るコンピュータの構成を示す概略ブロック図である。
　コンピュータ９００は、ＣＰＵ９０１、主記憶装置９０２、補助記憶装置９０３、入出力インタフェース９０４、通信インタフェース９０５を備える。
　上述の気泡パラメータ特定装置２００は、コンピュータ９００に実装される。そして、上述した各処理部の動作は、プログラムの形式で補助記憶装置９０３に記憶されている。ＣＰＵ９０１は、プログラムを補助記憶装置９０３から読み出して主記憶装置９０２に展開し、当該プログラムに従って上記処理を実行する。また、ＣＰＵ９０１は、プログラムに従って、上述した各記憶部に対応する記憶領域を主記憶装置９０２に確保する。 FIG. 5 is a schematic block diagram illustrating a configuration of a computer according to at least one embodiment.
The computer 900 includes a CPU 901, a main storage device 902, an auxiliary storage device 903, an input / output interface 904, and a communication interface 905.
The above-described bubble parameter specifying device 200 is mounted on the computer 900. The operation of each processing unit described above is stored in the auxiliary storage device 903 in the form of a program. The CPU 901 reads a program from the auxiliary storage device 903, develops it in the main storage device 902, and executes the above processing according to the program. Further, the CPU 901 secures a storage area corresponding to each of the above-described storage units in the main storage device 902 according to the program.
　なお、少なくとも１つの実施形態において、補助記憶装置９０３は、一時的でない有形の媒体の一例である。一時的でない有形の媒体の他の例としては、入出力インタフェース９０４を介して接続される外部ストレージ９１０およびネットワークＮを介して接続されるサーバ９２０が挙げられる。外部ストレージ９１０の例としては、磁気ディスク、光磁気ディスク、ＣＤ－ＲＯＭ（Compact Disc Read Only Memory）、ＤＶＤ－ＲＯＭ（Digital Versatile Disc Read Only Memory）、半導体メモリ等が挙げられる。
　プログラムがネットワークＮを介してサーバ９２０からコンピュータ９００に配信される場合、配信を受けたコンピュータ９００が当該プログラムを主記憶装置９０２に展開し、上記処理を実行してもよい。 In at least one embodiment, the auxiliary storage device 903 is an example of a tangible medium that is not temporary. Other examples of the non-transitory tangible medium include an external storage 910 connected via the input / output interface 904 and a server 920 connected via the network N. Examples of the external storage 910 include a magnetic disk, a magneto-optical disk, a CD-ROM (Compact Disc Read Only Memory), a DVD-ROM (Digital Versatile Disc Read Only Memory), and a semiconductor memory.
When the program is distributed from the server 920 to the computer 900 via the network N, the computer 900 that has received the distribution may develop the program in the main storage device 902 and execute the above processing.
　また、当該プログラムは、前述した機能の一部を実現するためのものであってもよい。さらに、当該プログラムは、前述した機能を補助記憶装置９０３に既に記憶されている他のプログラムとの組み合わせで実現する差分ファイル（差分プログラム）でもよい。 Further, the program may be for realizing a part of the functions described above. Further, the program may be a difference file (difference program) that realizes the above-described function in combination with another program already stored in the auxiliary storage device 903.
　また、他の実施形態においては、探触子制御部２０１、反射波記録部２０２、反射波記憶部２０３、気泡反射波抽出部２０４、伝播時間特定部２０５、対象内気泡特定部２０６、振幅特定部２０７、振幅正規化部２０８、抽出数情報生成部２０９、ヒストグラム記憶部２１０、気泡パラメータ特定部２１１、ボイド率特定部２１２の少なくとも一部がサーバ９２０に備えられ、その実行結果がコンピュータ９００に配信されるものであってもよい。つまり、気泡パラメータ特定システム１は、クラウドコンピューティングシステムやグリッドコンピューティングシステムにより実現されてもよい。 In another embodiment, the probe control unit 201, the reflected wave recording unit 202, the reflected wave storage unit 203, the bubble reflected wave extraction unit 204, the propagation time specifying unit 205, the in-target bubble specifying unit 206, the amplitude specifying Unit 207, amplitude normalization unit 208, extraction number information generation unit 209, histogram storage unit 210, bubble parameter identification unit 211, void ratio identification unit 212 are provided in server 920, and the execution result is stored in computer 900. It may be delivered. That is, the bubble parameter specifying system 1 may be realized by a cloud computing system or a grid computing system.
　気泡パラメータ特定装置は、気泡反射波の強度のばらつきを鑑みて、気泡に関するパラメータを特定することができる。 The bubble parameter identification device can identify a parameter related to bubbles in view of variations in the intensity of the bubble reflected wave.
１　気泡パラメータ特定システム
１００　超音波探触子
２００　気泡パラメータ特定装置
２０１　探触子制御部
２０２　反射波記録部
２０３　反射波記憶部
２０４　気泡反射波抽出部
２０５　伝播時間特定部
２０６　対象内気泡特定部
２０７　振幅特定部
２０８　振幅正規化部
２０９　抽出数情報生成部
２１０　ヒストグラム記憶部
２１１　気泡パラメータ特定部
２１２　ボイド率特定部 DESCRIPTION OF SYMBOLS 1 Bubble parameter specific system 100 Ultrasonic probe 200 Bubble parameter specific device 201 Probe control part 202 Reflected wave recording part 203 Reflected wave memory | storage part 204 Bubble reflected wave extraction part 205 Propagation time specific part 206 In-object bubble specific part 207 Amplitude specifying unit 208 Amplitude normalizing unit 209 Extraction number information generating unit 210 Histogram storage unit 211 Bubble parameter specifying unit 212 Void rate specifying unit

Claims (14)

  1. 　計測対象に含まれる気泡に関するパラメータを特定する気泡パラメータ特定装置であって、
    　前記計測対象へ向けて発信された送信波の反射波を受信する反射波受信部と、
    　受信した前記反射波から、前記計測対象に含まれる気泡によって反射された反射波である気泡反射波を抽出する気泡反射波抽出部と、
    　抽出された前記気泡反射波の振幅を特定する振幅特定部と、
    　前記気泡反射波の振幅と抽出数との関係を示す抽出数情報を生成する抽出数情報生成部と、
    　気泡径ごとに予め得られた、当該気泡径を有する気泡に送信波を照射した場合に観測される気泡反射波の振幅と出現率との関係を示す出現率情報と、特定された前記抽出数情報とに基づいて、前記計測対象に含まれる気泡の気泡径ごとの個数を特定する気泡パラメータ特定部と
    　を備える気泡パラメータ特定装置。     A bubble parameter specifying device for specifying a parameter related to a bubble included in a measurement object,
    A reflected wave receiving unit that receives a reflected wave of a transmission wave transmitted toward the measurement target;
    A bubble reflected wave extraction unit that extracts a bubble reflected wave that is a reflected wave reflected by a bubble included in the measurement target from the received reflected wave;
    An amplitude specifying unit for specifying the amplitude of the extracted bubble reflected wave;
    An extraction number information generating unit for generating extraction number information indicating the relationship between the amplitude of the bubble reflected wave and the extraction number;
    Appearance rate information indicating the relationship between the amplitude and appearance rate of bubble reflection waves observed when a transmission wave is irradiated to a bubble having the bubble size, obtained in advance for each bubble diameter, and the number of extractions specified A bubble parameter identification device comprising: a bubble parameter identification unit that identifies the number of bubbles included in the measurement target for each bubble diameter based on the information.
  2. 　抽出された前記気泡反射波それぞれについて、前記送信波の照射時刻から前記気泡反射波の受信時刻までの時間である伝播時間を特定する伝播時間特定部をさらに備える
    　請求項１に記載の気泡パラメータ特定装置。     The bubble parameter specification according to claim 1, further comprising: a propagation time specification unit that specifies a propagation time that is a time from an irradiation time of the transmission wave to a reception time of the bubble reflection wave for each of the extracted bubble reflection waves. apparatus.
  3. 　前記伝播時間に基づいて、前記気泡反射波のうち前記計測対象に含まれる気泡に反射したものを特定する対象内気泡特定部をさらに備え、
    　前記抽出数情報生成部が、前記対象内気泡特定部によって特定された前記気泡反射波の振幅と抽出数との関係を示す抽出数情報を特定する
    　請求項２に記載の気泡パラメータ特定装置。     Based on the propagation time, further comprising an in-target bubble specifying unit for specifying the reflected wave from the bubble reflected in the bubble included in the measurement target,
    The bubble parameter specifying device according to claim 2, wherein the extraction number information generation unit specifies extraction number information indicating a relationship between an amplitude of the bubble reflected wave specified by the in-target bubble specifying unit and the number of extractions.
  4. 　前記振幅特定部が特定した前記気泡反射波それぞれの振幅を、対応する前記伝播時間に基づいて正規化する振幅正規化部
    　をさらに備える請求項２または請求項３に記載の気泡パラメータ特定装置。     The bubble parameter specifying device according to claim 2, further comprising: an amplitude normalization unit that normalizes the amplitude of each of the bubble reflected waves specified by the amplitude specifying unit based on the corresponding propagation time.
  5. 　前記気泡パラメータ特定部が、前記出現率情報が示す振幅ごとの出現率の加重和が前記抽出数情報が示す振幅ごとの抽出数と近似するように、前記加重和の算出に用いる振幅ごとの重み係数を特定する
    　請求項１から請求項４の何れか１項に記載の気泡パラメータ特定装置。     A weight for each amplitude used for calculating the weighted sum so that the bubble parameter specifying unit approximates the weighted sum of the appearance rate for each amplitude indicated by the appearance rate information to the number of extractions for each amplitude indicated by the extracted number information. The bubble parameter specifying device according to any one of claims 1 to 4, wherein a coefficient is specified.
  6. 　前記気泡パラメータ特定部が、前記振幅ごとの重み係数に前記気泡反射波の総抽出数を乗算することで、前記計測対象に含まれる気泡の気泡径ごとの個数を特定する
    　請求項５に記載の気泡パラメータ特定装置。     The said bubble parameter specific | specification part specifies the number for every bubble diameter of the bubble contained in the said measurement object by multiplying the total extraction number of the said bubble reflected waves to the weighting coefficient for every said amplitude. Bubble parameter identification device.
  7. 　前記気泡パラメータ特定部が特定した前記計測対象に含まれる気泡の気泡径ごとの個数とに基づいて、前記計測対象のボイド率を特定するボイド率特定部をさらに備える
    　請求項１から請求項６の何れか１項に記載の気泡パラメータ特定装置。     The void ratio specific | specification part which specifies the void ratio of the said measurement object based on the number for every bubble diameter of the bubble contained in the said measurement object which the said bubble parameter specific | specification part specified is further provided. The bubble parameter specifying device according to any one of the above.
  8. 　前記反射波の包絡線を特定する包絡線処理部をさらに備え、
    　前記気泡反射波抽出部が、前記包絡線のピークに基づいて、前記気泡反射波を抽出する
    　請求項１から請求項７の何れか１項に記載の気泡パラメータ特定装置。     An envelope processing unit that identifies an envelope of the reflected wave;
    The bubble parameter specifying device according to any one of claims 1 to 7, wherein the bubble reflected wave extraction unit extracts the bubble reflected wave based on a peak of the envelope.
  9. 　前記振幅特定部が、前記包絡線のピークの振幅に基づいて前記振幅を特定する
    　請求項８に記載の気泡パラメータ特定装置。     The bubble parameter specifying device according to claim 8, wherein the amplitude specifying unit specifies the amplitude based on an amplitude of a peak of the envelope.
  10. 　前記気泡パラメータ特定部が、深さが異なる複数の前記計測対象からなる本計測対象に含まれる気泡の気泡径ごとの個数を、各深さの前記計測対象に含まれる前記気泡の気泡径ごとの個数の和を求めることで特定する
    　請求項１から請求項９の何れか１項に記載の気泡パラメータ特定装置。     The bubble parameter specifying unit calculates the number of bubbles for each bubble diameter included in the measurement target including the plurality of measurement targets having different depths for each bubble diameter of the bubbles included in the measurement target at each depth. The bubble parameter specifying device according to any one of claims 1 to 9, wherein the bubble parameter specifying device is specified by calculating a sum of the numbers.
  11. 　前記気泡パラメータ特定部が、深さごとに予め得られた前記出現率情報に基づいて、各深さの前記計測対象に含まれる前記気泡の気泡径ごとの個数の和を求めることで特定する
    　請求項１０に記載の気泡パラメータ特定装置。     The air bubble parameter specifying unit specifies the sum by obtaining the sum of the numbers of the air bubbles included in the measurement target at each depth for each air bubble diameter based on the appearance rate information obtained in advance for each depth. Item 10. The bubble parameter specifying device according to Item 10.
  12. 　前記送信波が縦波として鋼板を介して発信され、
    　前記送信波の前記鋼板における横波屈折角が４０度以上４５度以下である
    　請求項１から請求項１１の何れか１項に記載の気泡パラメータ特定装置。     The transmission wave is transmitted as a longitudinal wave through the steel plate,
    The bubble parameter specifying device according to any one of claims 1 to 11, wherein a transverse wave refraction angle of the transmission wave in the steel plate is not less than 40 degrees and not more than 45 degrees.
  13. 　計測対象に含まれる気泡に関するパラメータを特定する気泡パラメータ特定方法であって、
    　前記計測対象へ向けて発信された送信波の反射波を受信することと、
    　前記反射波から、前記計測対象に含まれる気泡によって反射された反射波である複数の気泡反射波を抽出することと、
    　抽出された前記複数の気泡反射波の振幅を特定することと、
    　前記複数の気泡反射波の振幅と抽出数との関係を示す抽出数情報を生成することと、
    　複数の気泡径ごとに予め得られた、前記気泡径を有する気泡に送信波を照射した場合に観測される気泡反射波の振幅と出現率との関係を示す出現率情報と、特定された前記抽出数情報とに基づいて、前記計測対象に含まれる気泡の気泡径と個数との関係を特定することと
    　を有する気泡パラメータ特定方法。     A bubble parameter specifying method for specifying a parameter related to a bubble included in a measurement object,
    Receiving a reflected wave of a transmission wave transmitted toward the measurement object;
    Extracting a plurality of bubble reflected waves that are reflected waves reflected by the bubbles included in the measurement object from the reflected waves;
    Identifying amplitudes of the extracted bubble reflected waves;
    Generating extraction number information indicating a relationship between the amplitude of the plurality of bubble reflected waves and the number of extractions;
    Appearance rate information, which is obtained in advance for each of a plurality of bubble diameters, indicates the relationship between the amplitude and the appearance rate of the bubble reflected wave observed when the transmission wave is irradiated to the bubble having the bubble diameter, and the identified A bubble parameter identification method comprising: identifying a relationship between a bubble diameter and a number of bubbles included in the measurement target based on extraction number information.
  14. 　計測対象に含まれる気泡に関するパラメータを特定する気泡パラメータ特定装置のコンピュータに、
    　前記計測対象へ向けて発信された送信波の反射波を受信することと、
    　前記反射波から、前記計測対象に含まれる気泡によって反射された反射波である複数の気泡反射波を抽出することと、
    　抽出された前記複数の気泡反射波の振幅を特定することと、
    　前記複数の気泡反射波の振幅と抽出数との関係を示す抽出数情報を生成することと、
    　複数の気泡径ごとに予め得られた、前記気泡径を有する気泡に送信波を照射した場合に観測される気泡反射波の振幅と出現率との関係を示す出現率情報と、特定された前記抽出数情報とに基づいて、前記計測対象に含まれる気泡の気泡径と個数との関係を特定することと
    　を実行させるためのプログラム。     In the computer of the bubble parameter identification device that identifies the parameters related to the bubbles included in the measurement target,
    Receiving a reflected wave of a transmission wave transmitted toward the measurement object;
    Extracting a plurality of bubble reflected waves that are reflected waves reflected by the bubbles included in the measurement object from the reflected waves;
    Identifying amplitudes of the extracted bubble reflected waves;
    Generating extraction number information indicating a relationship between the amplitude of the plurality of bubble reflected waves and the number of extractions;
    Appearance rate information, which is obtained in advance for each of a plurality of bubble diameters, indicates the relationship between the amplitude and the appearance rate of the bubble reflected wave observed when the transmission wave is irradiated to the bubble having the bubble diameter, and the identified A program for executing, based on the extraction number information, specifying the relationship between the bubble diameter and the number of bubbles included in the measurement target.
PCT/JP2017/003967 2016-02-18 2017-02-03 Bubble parameter identifying device, bubble parameter identifying method, and program WO2017141732A1 (en)

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010216872A (en) * 2009-03-13 2010-09-30 Yokogawa Electric Corp Ultrasonic measuring device
JP2015161663A (en) * 2014-02-28 2015-09-07 横河電機株式会社 Multi-phase flow meter

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2010216872A (en) * 2009-03-13 2010-09-30 Yokogawa Electric Corp Ultrasonic measuring device
JP2015161663A (en) * 2014-02-28 2015-09-07 横河電機株式会社 Multi-phase flow meter

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