Patent Application
20230112790
This disclosure relates to a signal processing method and device for ultrasonic inspection and thickness measuring method and device.
In ultrasonic inspection, an ultrasonic probe is driven by an electric signal so as to generate ultrasonic waves and to cause them to inject an inspection target, a reflective wave from the inspection target is converted to the electric signal and received, and a thickness, a distance and the like are measured on the basis of time from incidence of the ultrasonic waves to reception of the reflected wave. As the electric signal for driving the ultrasonic probe, it is known that an impulse or a burst wave signal, for example, is used.
Patent Literature 1 discloses an ultrasonic image apparatus using the burst wave signal as a transmitted signal which drives the ultrasonic probe.
By the way, when the ultrasonic probe is driven by using the burst wave signal, energy efficiency of the signal caused to inject the ultrasonic probe is higher as compared with a case where the impulse with wide frequency response is used. Therefore, measurement can be made by using an electric signal with a lower voltage, and it can be applied easily to a use under an inflammable gas atmosphere, for example. On the other hand, when the ultrasonic probe is driven by using the burst wave signal, a level of a detection signal based on the reflected wave is changed in accordance with a thickness, a frequency and the like of the inspection target, and there are measurement values (thickness and the like) whose detection voltage is in the vicinity of zero. Thus, the inspection target cannot be measured appropriately in some cases.
In view of the aforementioned circumstances, at least one embodiment of the present invention has an object to provide a signal processing method and a device for ultrasonic inspection and a thickness measurement method and a device which can measure an inspection target appropriately.
A signal processing method for ultrasonic inspection according to at least one embodiment of the present invention includes
a step of generating ultrasonic waves by driving an ultrasonic probe by using a plurality of burst wave signals with different frequencies, respectively, and causing the ultrasonic waves to inject an inspection target,
a receiving step of receiving a plurality of reflected waves corresponding to the plurality of burst wave signals having injected the inspection target, respectively,
a step of obtaining a plurality of detection signals by executing detection processing of receiving signals of the plurality of reflected waves corresponding to the plurality of burst wave signals, respectively, and
a generating step of generating an inspection signal for obtaining an inspection result related to the inspection target by using the plurality of detection signals.
Moreover, a thickness measuring method according to at least one embodiment of the present invention includes
a step of obtaining the inspection signal by the signal processing method; and
a step of determining a thickness of the inspection target by using the inspection signal.
Moreover, a signal processing device for an ultrasonic inspection according to at least one embodiment of the present invention includes
a burst wave oscillator configured to be capable of oscillating a plurality of burst wave signals with different frequencies,
an ultrasonic probe configured to generate ultrasonic waves by being driven by the burst wave signals so as to cause the ultrasonic waves to inject an inspection target and to receive reflected waves from the inspection target,
an inspection processing unit configured to execute inspection processing of receiving signals of the plurality of reflected waves corresponding to each of the plurality of burst wave signals and to obtain a plurality of detection signals, and
an inspection-signal generating unit generating an inspection signal for obtaining an inspection result related to the inspection target by using the plurality of detection signal.
Moreover, a thickness measuring device according to at least one embodiment of the present invention includes
the aforementioned signal processing device, and
a thickness calculation unit configured to calculate a thickness of the inspection target by using the inspection signal obtained by the signal processing device.
According to at least one embodiment of the present invention, a signal processing method and a device for ultrasonic inspection and a thickness measuring method and a device which can measure an inspection target appropriately are provided.
Hereinafter, some embodiments of the present invention will be described by referring to the attached drawings. However, dimensions, materials, shapes, relative disposition and the like of components described as the embodiments or illustrated in the drawings are not intended to limit the scope of the present invention to them but are only examples for explanation.
In the following, an example in which the signal processing method and device for ultrasonic inspection according to some embodiments are applied to thickness measurement will be described, but the signal processing method and device according to the present invention can be applied also to ultrasonic inspection other than the thickness measurement. For example, the signal processing method and device according to some embodiments can be applied also to an ultrasonic flaw detecting device, an ultrasonic microscope and the like.
(Constitution of Thickness Measuring Device and Signal Processing Device)
First, by referring to
The signal processing device 2 includes a burst-wave oscillator 10 constituted capable of oscillating a burst wave signal, a transmission unit 16 which causes the burst wave signal to inject an ultrasonic probe 6, a receiving unit 18 which receives a receiving signal from the ultrasonic probe 6, an inspection processing unit 20 for obtaining a detection signal by inspection processing of the receiving signal, and an inspection-signal generating unit 30 for generating an inspection signal on the basis of the detection signal. Elements (a signal generator 11, a timing-pulse generator 12, a mixer 14 and the like, which will be described later) constituting the oscillator 16, the receiving unit 18, and the burst-wave oscillator 10 and elements (a phase shifter 24, a processing unit 28 and the like, which will be described later) constituting the inspection processing unit 20 are electrically connected as shown in the figure.
The burst-wave oscillator 10 includes the signal generator 11 capable of generating a continuous sine-wave signal (electric signal), the timing-pulse generator 12 for generating a timing pulse which turns ON/OFF the signal from the signal generator 11 at a specified timing, and the mixer 14. By mixing the continuous sine-wave signal and the timing pulse by the mixer 14, a burst wave signal obtained by cutting out a specified length from the continuous sine-wave signal is generated. It may be so constituted that, instead of the timing-pulse generator 12, the burst wave may be generated by generating a timing pulse from the processing unit 28 which will be described later. Moreover, the generation of the burst wave can be realized also by using an analog switch instead of the mixer 14. The signal generator 11 is constituted capable of changing a frequency of the continuous sine-wave signal to be generated. That is, the burst-wave oscillator 10 is constituted capable of oscillating a plurality of burst wave signals with different frequencies (that is, the burst wave signals with the frequencies f1, f2, . . . fN, where n≥2). The burst wave signal oscillated by the burst-wave oscillator 10 is configured to be sent to the transmission unit 16.
The transmission unit 16 is configured to apply the burst wave signal received from the burst-wave oscillator 10 to the ultrasonic probe 6. In order to drive the ultrasonic probe 6 appropriately, the transmission unit 16 may be configured to apply the burst wave signal from the burst-wave oscillator 10 to the ultrasonic probe after amplification.
The ultrasonic probe 6 is configured to be driven by the burst wave signal received from the transmission unit 16, to generate an ultrasonic wave, and to inject it to an inspection target (the pipe 50, for example). In
The receiving unit 18 is configured to send out the receiving signal received from the ultrasonic probe 6 to the inspection processing unit 20. In order to execute the inspection processing at the inspection processing unit 20 appropriately, the receiving unit 18 may be configured to send out the received signal from the ultrasonic probe 6 to the inspection processing unit 20 after amplification.
The inspection processing unit 20 is configured to execute the inspection processing of the receiving signal received from the receiving unit 18 and to obtain the detection signal. The detection signal is a detection signal indicating the reflected wave 102 from the inspection target and is a signal including information indicating a traveling time from application of the burst wave signal by the transmission unit 16 to the ultrasonic probe 6 to reception of the receiving signal of the reflected wave 102 at the receiving unit 18 and a signal level (detection voltage) of the reflected wave 102.
In the mixer 22, the receiving signal from the receiving unit 18 and the continuous sine-wave signal from the signal generator 11 are mixed, and an I-phase signal (In-phase signal) is obtained. Moreover, in the mixer 26, the receiving signal from the receiving unit 18 and the continuous sine-wave signal from the signal generator 11 are mixed with a signal whose phase was shifted only by 90 degrees by the phase shifter 24, and a Q-phase signal (Quadrature-phase signal) is obtained. The I-phase signal and the Q-phase signal obtained as above are sent to the processing unit 28. It may be so configured that the I-phase signal and the Q-phase signal based on the receiving signal are sent to the processing unit 28 after being attenuated by an attenuator or after a frequency component of the inspection target is amplified by an intermediate-frequency amplifier. In the processing unit 28, inspection is conducted on the basis of the I-phase signal and the Q-phase signal, and the detection signal indicating the reflected wave 102 is taken out of the receiving signal.
In the inspection processing unit 20, the detection signal according to the frequency of the burst wave signal is obtained. That is, when the ultrasonic waves based on the burst wave signals with the frequencies f1, f2, . . . , fN are caused to inject the same inspection target (the pipe 50, for example) by the burst-wave oscillator 10, the inspection processing unit 20 executes the inspection processing of the receiving signals corresponding to the burst wave signals with the frequencies f1, f2, . . . , fN, respectively, whereby a plurality of the detection signals SD1, SD2, . . . , SDN corresponding to the burst wave signals with the frequencies f1, f2, . . . , fN are obtained.
The detection signal obtained in the inspection processing unit 20 is sent out to the inspection-signal generating unit 30.
The inspection-signal generating unit 30 is configured to generate an inspection signal for obtaining an inspection result (a thickness, for example) related to the inspection target (the pipe 50, for example) on the basis of the plurality of detection signals (the detection signals SD1, SD2, . . . , SDN corresponding to the burst wave signals with the frequencies f1, f2, . . . , fN, respectively) received from the inspection processing unit 20. The inspection signal generated in the inspection-signal generating unit 30 is sent out to a thickness calculation unit 4. A procedure for generating the inspection signal on the basis of the plurality of detection signals in the inspection-signal generating unit 30 will be described later.
The thickness calculation unit 4 is configured to calculate a thickness of the inspection target (the pipe 50, for example) on the basis of the inspection signal received from the inspection-signal generating unit 30. The thickness D of the inspection target (the pipe 50, for example) can be expressed by the following formula (A) by using a speed of sound cs in a material of the inspection target and time T from incidence of the ultrasonic wave from the ultrasonic probe 6 to the inspection target to reception by the ultrasonic probe 6 of the reflected wave from the inspection target:
c
s
×T=2D (A)
The aforementioned time T can be obtained from the inspection signal. Therefore, the thickness calculation unit 4 may be configured to calculate the thickness D of the inspection target on the basis of the aforementioned formula.
(Signal Processing Device and Signal Processing Method)
Subsequently, the signal processing method according to some embodiments will be described along the flowchart shown in
In the signal processing method according to the one embodiment, first, by oscillating the burst wave signal of the specified frequency f1 (n=1) from the burst-wave oscillator 10 and by applying the burst wave signal to the ultrasonic probe 6 through the transmission unit 16 so as to drive the ultrasonic probe 6, the ultrasonic waves are generated (Step S2). Moreover, the ultrasonic waves generated at Step S2 are caused to inject the inspection target (the pipe 50, for example) (Step S4).
The burst wave signal oscillated from the burst-wave oscillator 10 at Step S2 may be a continuous sine-wave signal as shown in
Subsequently, in the ultrasonic probe 6, a reflected wave 102 (see
The receiving signal obtained at Step S6 has a waveform as shown in
Subsequently, in the inspection processing unit 20, by executing the inspection processing of the aforementioned receiving signal (receiving signal corresponding to the burst wave signal with the frequency f1) received through the receiving unit 18, the detection signal (see
At Step S8, the I-phase signal and the Q-phase signal are generated on the basis of the receiving signal from the receiving unit 18 and the continuous sine-wave signal from the signal generator 11, for example (see
By means of the aforementioned Steps S2 to S8, the detection signal SD1 corresponding to the burst wave signal with the frequency f1 is obtained.
Subsequently, the frequency of the burst wave signal is changed to the specified frequency f2 (Steps S10 to S12), and similarly to the case of the aforementioned frequency f1 of the burst wave signal, Steps S2 to S8 are executed, and the detection signal SD2 corresponding to the burst wave signal with the frequency f2 is obtained.
Similarly, the frequency of the burst wave signal is changed up to the specified frequency fN (Steps S10 to S12), and at each time, similarly to the case of the aforementioned frequency f1 of the burst wave signal, Steps S2 to S8 are executed. As described above, the plurality of detection signals SD1, SD2, . . . , SDN corresponding to the burst wave signals with the frequencies f1, f2, . . . , fN, respectively, are obtained. The intensity of each of the burst wave signals with the frequencies f1, f2, . . . , fN is preferably made the same.
A peak appearing in the vicinity of time 0 [μs] in the graph in
As shown in
Though not particularly illustrated, in the second reflected wave and after, too, the feature that the time when the voltage peak appears substantially coincide, but the voltage levels at the peaks are different from each other is similar to that of the first reflected wave.
And at Step S14, the inspection signal ST for obtaining an inspection result related to the inspection target (a thickness of the inspection target, for example) is generated from the plurality of detection signals SD1 to SDN obtained as above.
As shown in
Here,
In the ultrasonic inspection using the burst wave signal, the signal level (voltage) of the detection signal obtained by inspection processing of the receiving signal based on the reflected wave is fluctuated by interference between the incident wave to the inspection target and the reflected wave from the inspection target depending on the thickness of the inspection target and the like. For example, as shown in
Here, when an absolute value of the signal level of the detection signal corresponding to the actual thickness D of the inspection target is in the vicinity of the maximum value (VA in
On the other hand, the signal level of the detection signal SDb obtained on the basis of the burst wave signal with the frequency fb different from the frequency fa is, as shown in
In this point, according to the method according to the aforementioned embodiment, by using a plurality of the burst wave signals with different frequencies (that is, the burst wave signal with any one of the frequencies f1 of fN), respectively, for an inspection target (the pipe 50, for example), the plurality of detection signals SD1 to SDN corresponding to the plurality of burst wave signals, respectively, are obtained, and the inspection signal ST is generated. Therefore, by using the inspection signal ST generated as above, the aforementioned time T (time T from the incidence of the ultrasonic wave from the ultrasonic probe 6 to the inspection target to reception of the reflected wave by the ultrasonic prove 6 from the inspection target) can be obtained appropriately on the basis of the peak voltage of the inspection signal ST regardless of the thickness of the like of the inspection target, and the thickness or the like of the inspection target can be measured appropriately. Thus, the thickness or the like of the inspection target can be measured appropriately by using the electric signal (burst wave signal) at a lower voltage as compared with the case where the impulse is used and thus, appropriate ultrasonic inspection (measurement) can be conducted even under an inflammable gas atmosphere or the like. Moreover, it can be suitably applied to continuous thickness measurement of the inspection target whose thickness can change with elapse of time (a pipe which can be thinner by erosion or the like with elapse of time, for example), for example.
In some embodiments, at the aforementioned Step S14, the aforementioned inspection signal ST is generated on the basis of the statistic amount of the signal levels of the plurality of detection signals SD1 to SDN corresponding to the plurality of burst wave signals with different frequencies (frequencies f1 to fN). The aforementioned statistic amount may be an average value, a maximum value, an n-th maximum value, a median value and the like of the signal levels of the plurality of detection signals SD1 to SDN.
In this case, by using the statistic amount of the signal levels of the plurality of detection signals SD1 to SDN, the inspection signal ST considering the detection signal with a relatively high signal level other than the level minimum signal can be generated. Thus, measurement can be conducted appropriately regardless of the thickness or the like of the inspection target.
For example, at the aforementioned Step S14, the inspection signal ST may be generated on the basis of a summation value or an average value of the signal levels of the plurality of detection signals SD1 to SDN. The inspection signal ST illustrated in
In this case, by using the summation value or the average value of the signal levels of the plurality of detection signals SD1 to SDN, the inspection signal ST considering the detection signal with a relatively high signal level other than the level minimum signal can be generated. Thus, measurement can be conducted appropriately regardless of the thickness or the like of the inspection target. Since the signal levels of the detection signals are periodically changed with respect to the frequency change of the burst wave signal, the summation value or the average value of the signal levels of the plurality of detection signals become a value close to a predetermined value regardless of the thickness or the like of the inspection target, and the measurement of the inspection target can be conducted more reliably.
Here,
When the ultrasonic waves propagate in a member, a disturbance noise is generated due to micro scattering, reflection and the like in the middle of the propagation. In the detection signal SDn based on the burst wave signal with a specific frequency fn, as shown in
On the other hand, a propagation state of the ultrasonic waves in the member is changed if the frequency of the burst wave signal is changed. Thus, as in the aforementioned embodiment, with the inspection signal ST obtained as the average value of the plurality of detection signals SD1 to SDN, the disturbance noise (the waveform in the region indicated by A in
Moreover, at the aforementioned Step S14, the inspection signal may be generated on the basis of the maximum value of the signal levels of the plurality of detection signals SD1 to SDN (the signal level of the detection signal SD2 in the case shown in
In this case, by using the maximum value of the signal levels of the plurality of detection signals SD1 to SDN, the inspection signal ST considering the detection signal with the relatively highest signal level in the plurality of detection signals SD1 to SDN can be generated. Thus, the measurement can be conducted appropriately regardless of the thickness or the like of the inspection target.
In the one embodiment, at the aforementioned Step S6, it may be so configured that, after the application of the burst wave signal oscillated from the burst-wave oscillator 10 to the ultrasonic probe 6 is finished, the reflected wave 102 from the inspection target is received at the ultrasonic probe 6.
In the example shown in
When the burst wave signal is applied to the ultrasonic probe 6 as shown in
In
The receiving signal obtained by receiving the reflected wave from the inspection target in a state where the burst wave signal is being applied to the ultrasonic probe 6 is superimposed with the transmission signal (burst wave signal) and thus, if the receiving signal becomes small, it is masked by the transmission signal, and detection of the receiving signal becomes difficult. In this point, according to the aforementioned embodiment, it is configured such that the reflected wave from the inspection target (the pipe 50 or the like) is received after the application of the burst wave signal to the ultrasonic probe 6 is finished and thus, the receiving signal and the detection signals SD1 to SDN not affected by the transmission signal can be obtained. Thus, the S/N ratio of the inspection signal ST can be further improved and thus, the measurement accuracy can be improved.
Each of the frequencies f1 to fN of the plurality of burst wave signals (burst wave signal generated at Step S2) used in the method according to the embodiment described above may be set appropriately in accordance with the thickness D of the inspection target (the pipe 50, for example) or may be set as described below, for example.
Assuming that the thickness of the inspection target is Dmin or more at the smallest, a minimum path length of the ultrasonic wave in the inspection target is 2×Dmin. That is, assuming that the speed of sound in the material of the inspection target is cs, an amount of phase change θa with the minimum frequency fa of the burst wave signal can be expressed by the following formula (B):
θa=2Dmin/Cs×fa (B)
On the other hand, the phase rotation amount θb at the maximum frequency fb can be expressed by the following formula (C):
θb=2Dmin/Cs×fb (C)
Here, a condition that the inspection signal is sufficiently changed, and averaging becomes effective is the following formula (D):
θb−θa≥π/2 (D)
Therefore, a width Δf of fb and the frequency fa is determined by the following formula (E):
Δf=fb−fa≤π/2×Cs/(2Dmin)=Cs/Dmin×π/4 (E)
From the viewpoint of the detection efficiency, the central frequency (fb−fa)/2 preferably should be selected at the center of the central frequency of the ultrasonic probe 6. Similarly, from the viewpoint of the detection efficiency, Δf is also preferably set within a bandwidth of the ultrasonic probe 6.
That is, by using the burst wave signals in plural in the frequency band within a range of such a degree that the width Δf of the frequency is expressed by the aforementioned formula (E), the detection signal SD having various signal levels can be obtained correspondingly to the thickness of the inspection target. Moreover, regarding the inspection target with the thickness larger than Dmin, by using a plurality of the burst wave signals in the frequency band within the range of the approximate width Δf acquired as above, the detection signals SD having the various signal levels can be obtained.
A pitch (interval) of each frequency fn (f1, f2, . . . , fN) of the burst wave signal within the range of the aforementioned width Δf can be the one obtained by dividing the aforementioned width Δf into 10 to 20 parts. As a result, the detection signal SD having the various signal levels including the relatively large voltage level corresponding to each thickness of the inspection target can be obtained, and appropriate inspection signals can be obtained easily.
As an example, assuming that the thickness of the pipe 50 as the inspection target has at least 5 mm or more, by substituting Dmin: 5×10−3 [m] and the speed of sound cs: 5.92×103 [m/s] in the case where the pipe 50 is made of steel into the aforementioned formula (E), the aforementioned frequency width Δf is calculated as approximately 0.94 MHz. Moreover, if this Δf is divided into 20 parts (N=20), for example, the pitch (interval) of each frequency fn of the plurality of burst wave signals is approximately 50 kHz. Therefore, as the frequency of the plurality of burst wave signals, by using each frequency fn with the pitch set to 50 kHz for f1=10 MHz to f20=11 MHz in the signal processing method according to the embodiment described above, the inspection signal ST which can appropriately calculate the thickness of the pipe 50 can be obtained.
Contents described in each of the embodiments are grasped as follows, for example.
(1) The signal processing method for ultrasonic inspection according to at least one embodiment of the present invention includes
a step (Steps S2, S4 described above, for example) of generating ultrasonic waves by driving the ultrasonic probe (6) by using the plurality of burst wave signals with different frequencies, respectively, and causing the ultrasonic waves to inject the inspection target,
a receiving step (Step S6 described above, for example) of receiving the plurality of reflected waves corresponding to the plurality of burst wave signals having injected the inspection target, respectively,
a step (Step S8 described above, for example) of obtaining the plurality of detection signals by executing the inspection processing of the receiving signals of the plurality of reflected waves corresponding to the plurality of burst wave signals, respectively, and
a generating step (Step S14 described above, for example) of generating the inspection signal for obtaining an inspection result related to the inspection target by using the plurality of detection signals.
In the ultrasonic inspection using the burst wave signal, a level (voltage) of the detection signal obtained by inspection processing of the receiving signal based on the reflected wave can be zero or a small value in the vicinity of zero in some cases due to interference of the incident wave into the inspection target and the reflected wave from the inspection target depending on the thickness or the like of the inspection target. In this point, according to the aforementioned method (1), for an inspection target, a plurality of inspection signals corresponding to the plurality of burst wave signals, respectively, are obtained by using the plurality of burst wave signals with different frequencies, respectively, and the inspection signal is generated by using the plurality of detection signals. That is, the plurality of detection signals having the different signal levels according to the frequency of the burst wave signal are obtained, and the inspection signal is generated by using the plurality of detection signals. Therefore, by using the inspection signal generated as above, appropriate measurement can be conducted regardless of the thickness or the like of the electric signal (burst wave signal). Thus, the inspection target can be appropriately measured by using the electric signal (burst wave signal) with a relatively low voltage, for example, and thus, the appropriate ultrasonic inspection (measurement) can be conducted even under the inflammable gas atmosphere or the like.
(2) In some embodiments, in the method of the aforementioned (1),
in the generating step, the inspection signal is generated on the basis of the statistic amount of the signal levels of the plurality of detection signals.
According to the aforementioned method (2), by using the statistic amount of the signal levels of the plurality of detection signals, the inspection signal can be generated. Thus, the measurement can be conducted appropriately regardless of the thickness or the like of the inspection target.
(3) In some embodiments, in the aforementioned method (2),
in the generating step, the inspection signal is generated on the basis of the summation value of the signal levels of the plurality of detection signals.
(4) In some embodiments, in the aforementioned method (2) or (3),
in the generating step, the inspection signal is generated on the basis of the average value of the signal levels of the plurality of detection signals.
According to the aforementioned method (3) or (4), by using the summation value or the average value of the signal levels of the plurality of detection signals, the inspection signal can be generated. Thus, the measurement can be conducted appropriately regardless of the thickness or the like of the inspection target. Since the signal level of the detection signal is changed periodically with respect to the frequency change of the burst wave signal, the summation value or the average value of the signal levels of the plurality of detection signals becomes a value close to a predetermined value regardless of the thickness or the like of the inspection target and thus, the measurement of the inspection target can be conducted more reliably.
Moreover, when the frequency of the burst wave signal is changed, the frequency of the ultrasonic wave caused to inject the inspection target is also changed, and the propagation state of the ultrasonic waves in the inspection target is changed. In this point, according to the aforementioned method (3) or (4), by summating or averaging the signal levels of the plurality of detection signals obtained by changing the frequency of the burst wave signal, the S/N ratio to the disturbance noise of the inspection signal can be improved, and the measurement accuracy can be improved.
(5) In some embodiments, in the aforementioned method (2),
in the generating step, the inspection signal is generated on the basis of the maximum value of the signal levels of the plurality of detection signals.
According to the aforementioned method (5), by using the maximum value of the signal levels of the plurality of detection signals, the inspection signal can be generated. Thus, the measurement can be conducted appropriately regardless of the thickness or the like of the inspection target.
(6) In some embodiments, in any one of the aforementioned methods (1) to (5),
in the receiving step, the reflected wave is received after the application of each of the burst wave signals to the ultrasonic probe is finished.
The receiving signal obtained by receiving the reflected wave from the inspection target in the state where the burst wave signal is applied to the ultrasonic probe is superimposed with the transmission signal (burst wave signal) and thus, if the receiving signal becomes small, it is masked by the transmission signal, and detection of the receiving signal becomes difficult. In this point, according to the aforementioned method (6), it is configured such that the reflected wave from the inspection target is received after the application of the burst wave signal to the ultrasonic probe is finished and thus, the receiving signal and the detection signal not affected by the transmission signal can be obtained. Therefore, the S/N ratio of the inspection signal can be further improved, and the measurement accuracy can be improved.
(7) The thickness measuring method according to at least one embodiment of the present invention includes
a step of obtaining an inspection signal by the signal processing method described in any one of the aforementioned (1) to (6), and a step of determining a thickness of the inspection target by using the inspection signal.
According to the aforementioned method (7), the inspection signal for obtaining a thickness of the inspection target by the method described in (1) is generated. Therefore, therefore, by using the inspection signal generated as above, the thickness of the inspection target can be measured appropriately regardless of the thickness of the inspection target.
(8) The signal processing device (2) for ultrasonic inspection according to at least one embodiment of the present invention includes
a burst wave oscillator (10) configured to be capable of oscillating a plurality of burst wave signals with different frequencies,
an ultrasonic probe (6) configured to generate ultrasonic waves by being driven by the burst wave signals so as to cause the ultrasonic waves to inject an inspection target and to receive reflected waves from the inspection target;
an inspection processing unit (20) configured to execute inspection processing of receiving signals of the plurality of reflected waves corresponding to the plurality of burst wave signals, respectively, and to obtain a plurality of detection signals, and
an inspection-signal generating unit (30) generating an inspection signal for obtaining an inspection result related to the inspection target by using the plurality of detection signals.
According to the configuration of the aforementioned (8), for an inspection target, a plurality of detection signals corresponding to the plurality of burst wave signals, respectively, are obtained by using the plurality of burst wave signals with different frequencies, respectively, and the inspection signal is generated by using the plurality of detection signals. That is, the plurality of detection signals having the different signal levels according to the frequency of the burst wave signal are obtained, and the inspection signal is generated by using the plurality of detection signals. Therefore, by using the inspection signal generated as above, appropriate measurement can be conducted regardless of the thickness or the like of the inspection target. Thus, the inspection target can be appropriately measured by using the electric signal (burst wave signal) with a relatively low voltage, for example and thus, the appropriate ultrasonic inspection (measurement) can be conducted even under the inflammable gas atmosphere or the like.
(9) The thickness measuring device (1) according to at least one embodiment of the present invention includes
the signal processing device (2) described in the aforementioned (8), and
a thickness calculation unit (4) configured to calculate a thickness of the inspection target by using the inspection signal obtained by the signal processing device.
According to the configuration of the aforementioned (9), the inspection signal for obtaining the thickness of the inspection target is generated by the signal processing device described in the aforementioned (8). Therefore, therefore, by using the inspection signal generated as above, the thickness of the inspection target can be measured appropriately regardless of the thickness of the inspection target.
The embodiment of the present invention has been described so far, but the present invention is not limited to the aforementioned embodiment but includes a form obtained by adding deformation to the aforementioned embodiment or a form combining these forms as appropriate.
In this description, expressions expressing relative or absolute disposition such as “in a direction”, “along a direction”, “parallel”, “orthogonal”, “center”, “concentric”, “coaxial” and the like express not only strictly such disposition but also a state with relative displacement with a tolerance or an angle or a distance of such a degree that the same function is obtained.
For example, the expressions expressing a state in which matters are equal such as “same”, “equal”, “uniform”, and the like express not only the strictly equal state but also the state in which a tolerance or a difference of such a degree that the same function is present.
Moreover, in this description, the expressions expressing shapes such as a square shape, a cylindrical shape and the like express not only the shapes such as a square shape or a cylindrical shape and the like in strictly geographical meaning but also shapes including irregular parts, chamfered parts and the like within a range by which the same effects are obtained.
Furthermore, in this description, expressions of “including”, “containing”, or “having” one constituent element are not exclusive expressions excluding presence of the other constituent elements.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2020-026635 | Feb 2020 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2021/005029 | 2/10/2021 | WO |
