JP2016145757A - Ultrasonic diagnostic apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an apparatus capable of accurately detecting the depth of damage of a structure with an ultrasonic wave.SOLUTION: An ultrasonic diagnostic apparatus comprises: a first probe 12 arranged on the surface of a test piece on which an acoustic discontinuous portion is generated and emitting ultrasonic waves to the test piece; a second probe 13 arranged at the position on the surface of the test piece sandwiching the acoustic discontinuous portion with the first probe, and receiving the ultrasonic waves emitted from the first probe and propagating in the test piece; and a determination part which determines the property and condition of the test piece on which the acoustic discontinuous portion is generated from information on the ultrasonic wave within a gate period of the ultrasonic waves received by the second probe.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an ultrasonic diagnostic apparatus that determines the properties of a specimen such as a concrete structure in which cracks, which are acoustic discontinuities, have occurred.

  In recent years, damage to structures has become obvious, and appropriate maintenance is required.

  Especially in concrete structures, for example, cracking is a problem as damage, and if the crack is shallow, it does not affect the strength of the structure so much, but if the crack is deep, the strength of the structure is low. Since it has deteriorated, it is necessary to repair it.

  For this reason, there is a demand for a technique for diagnosing the properties of a structure not only by detecting cracks but also by determining the approximate depth of cracks. Since the depth of cracks cannot be measured with the naked eye, diagnosis by ultrasound is expected.

  FIG. 14 is an explanatory view showing a conventional ultrasonic measurement method (see Patent Document 1).

  In this conventional ultrasonic measurement method, when measuring a crack (crack) 102 generated in a concrete specimen 101, the transmitting probe 201 and the receiving probe 202 are placed between the concrete specimen so as to sandwich the crack 102. Of the ultrasonic waves radiated from the transmitting probe 201, the receiving probe 202 receives the ultrasonic waves diffracted at the tip of the crack 102, and the length of the crack 102 is set. To measure.

  This conventional ultrasonic measurement method is based on the premise that the ultrasonic waves diffracted at the tip of the crack 102 can be clearly received. However, the actual concrete specimen 101 may receive not only the ultrasonic wave diffracted at the tip of the crack 102 but also various ultrasonic echoes whose propagation path is difficult to explain. In such a case, even if the receiving probe 202 receives an ultrasonic wave, the length of the crack 102 cannot be measured.

JP 59-46503 (FIG. 1)

  Since the conventional ultrasonic measurement method is configured as described above, not only the ultrasonic wave diffracted at the tip of the crack 102 but also various ultrasonic echoes whose propagation paths are difficult to explain are received. Cannot measure the length of the crack 102. For this reason, the degree of strength deterioration of the concrete specimen 101 due to the crack 102 is not known, and there is a problem that the properties of the concrete specimen 101 (for example, whether or not the specimen 101 needs to be repaired) cannot be determined.

  The present invention has been made to solve the above-described problems, and is capable of easily diagnosing whether the acoustic discontinuity generated on the surface layer of the specimen is damage that affects the strength of the specimen. An object is to obtain an ultrasonic diagnostic apparatus.

  The ultrasonic diagnostic apparatus according to the present invention is arranged on the surface of a test body in which an acoustic discontinuity occurs, and a first probe that emits ultrasonic waves into the test body, and a first probe A second ultrasonic wave is disposed at a position on the surface of the test body that is paired with the child and sandwiches the acoustic discontinuity, and receives the ultrasonic wave that has propagated through the test body after being emitted from the first probe. The determination unit that determines the property of the test body in which the acoustic discontinuity occurs from the ultrasonic information within the gate period among the ultrasonic waves received by the second probe and the second probe And with.

  According to the present invention, the property of the test object is determined from the ultrasonic information within the gate period among the ultrasonic waves that are radiated to the test object in which the acoustic discontinuity occurs and propagated through the test object. Since it comprised as mentioned above, there exists an effect which can be easily diagnosed whether the acoustic discontinuity which arose in the surface layer of the test body is the damage which affects the intensity | strength of a test body.

It is a block diagram which shows an example of the ultrasonic diagnosing device by Embodiment 1 of this invention. 2 is a cross-sectional view showing a structure of a test body 1. FIG. It is a non-defective diagnosis explanatory drawing. It is an explanatory view of the diagnosis status of defective products. It is a schematic diagram of the signal waveform received by the test body. It is explanatory drawing of the interface V path | route. It is sectional drawing which shows a slit test body. It is a wave form diagram of a received signal obtained by experimenting with a slit specimen. It is a figure which shows the relationship between the value of the maximum amplitude in a gate period, and slit depth. It is a figure which shows the relationship between the signal integration value in a gate period, and slit depth. It is explanatory drawing of a boundary surface echo. It is a figure which shows an example of the interface echo received by experiment. It is a block diagram which shows an example of the ultrasonic diagnosing device by Embodiment 2 of this invention. It is explanatory drawing which shows the conventional ultrasonic measurement method.

Embodiment 1 FIG.
1 is a block diagram showing an example of an ultrasonic diagnostic apparatus according to Embodiment 1 of the present invention.

  Here, the test body 1 that is diagnosed with ultrasonic waves by the ultrasonic diagnostic apparatus is a structure in which a crack 2 that is an acoustic discontinuity is generated. First, the test body 1 will be described. FIG. 2 is a cross-sectional view showing the structure of the test body 1. The test body 1 is a structure in which a mortar 1b is applied as a surface layer on a concrete 1a, and cracks 2 that are acoustic discontinuities are generated. The concrete 1a and the mortar 1b have a boundary surface 1c as a boundary, and the concrete 1a includes an aggregate 1d.

  In FIG. 1, the ultrasonic diagnostic apparatus includes a transceiver 10, a first probe 12, and a second probe 13. The transceiver 10 includes a transmission unit 11, a reception unit 14, a determination unit 15, a display unit 16, and a control unit 21.

  The transmission unit 11 of the transceiver 10 transmits an electric signal to the first probe 12.

  The first probe 12 is driven by receiving an electrical signal from the transmitter 11 and radiates ultrasonic waves to the test body 1.

  The second probe 13 is disposed at a position on the surface of the test body 1 that is paired with the first probe 12 and sandwiches the crack 2. Then, the ultrasonic wave propagating through the test body 1 is received, and the ultrasonic wave is converted into an electric signal.

  In the example of FIG. 1, the first probe 12 is arranged on the left side with respect to the crack 2 which is an acoustic discontinuity generated on the surface of the test body 1, and the second probe 13 is arranged on the right side.

  The receiver 14 of the transceiver 10 receives the electrical signal converted by the second probe 13 and outputs it to the determination unit 15.

  The determination unit 15 of the transmitter / receiver 10 receives an ultrasonic electric signal from the receiving unit 14, performs signal processing on the electric signal received within the gate period, analyzes the characteristic, and the property of the specimen 1 in which the crack 2 is generated. Determine. Here, the property of the test body 1 is, for example, whether or not the test body needs repair. The determination unit 15 is configured as a property determination unit.

  The display unit 16 of the transceiver 10 displays the determination result of the determination unit 15, the waveform of the ultrasonic wave received by the second probe 13, and the like. In addition, information such as the set gate and the thickness of the mortar 1b is displayed. When displaying the waveform of the ultrasonic wave received by the second probe 13, a signal line for directly receiving the waveform from the receiver 13 as shown in FIG. You may receive via the determination part 15 without providing the signal line to perform. The display unit 16 does not necessarily have to be provided inside the transmitter / receiver 10. The display unit 16 is provided with an interface for outputting display information and connected to the external display unit 16. May be displayed. Here, the display unit 16 to be externally connected is not limited to a wired connection, and a display unit of a wirelessly connected display terminal may be used.

  The control unit 21 of the transceiver 10 controls the operation by outputting control signals to the transmission unit 11, the reception unit 14, the determination unit 15, and the display unit 16.

  In addition, the control part 21 and the determination part 15 of the transmitter / receiver 10 can be comprised, for example from the semiconductor integrated circuit which mounted CPU, or a one-chip microcomputer. These controls and determinations are not limited to hardware, software, and combinations thereof. Further, the program may be executed by a computer.

  Next, the operation will be described.

  FIG. 2 is a cross-sectional view showing the structure of the test body 1. As shown in FIG. 2, a concrete structure for building often has a mortar 1b applied on a concrete 1a. In this case, it becomes a two-layer structure of concrete 1a and mortar 1b.

  The crack 2 occurring in the surface layer portion of the specimen 1 may be detected by visual inspection or the like, but the crack 2 occurring in the surface layer portion also affects the strength of the specimen 1. It is not possible to determine whether the crack is present.

  Here, in the case of the two-layer structure of the concrete 1a and the mortar 1b, when the depth of the crack 2 is the mortar layer stop, the strength as a structure is not deteriorated so much. On the other hand, when the crack 2 extends to the depth of the lower concrete 1a, the strength as a structure is deteriorated. Therefore, if the strength of the structure can be roughly determined by whether the depth of the crack 2 is a mortar layer that is the surface layer or whether it reaches the depth of the concrete 1a beyond the boundary surface 1c, it is a great guideline for repair. It can be said.

  Hereinafter, the content of this invention is demonstrated about the case where the test body 1 is a 2 layer structure of the concrete 1a and the mortar 1b. First, an explanation will be given regarding the ultrasonic waves received by the second probe 13 with reference to FIGS. 3, 4 and 5.

  FIG. 3 is a diagram showing a diagnosis situation for a state in which the crack 2 is stopped by the mortar 1b. Since the crack 2 stops at the mortar 1b, this is determined as “good”. On the other hand, FIG. 4 is a figure which shows the diagnostic condition which made the object the state where the crack 2 has reached the back of the concrete 1a. Since the crack 2 reaches the depth of the concrete 1a beyond the boundary surface 1c, it is determined as a “defective product”.

  3 and 4, the thickness of the mortar 1 b is different, but the crack 2 is drawn at the same depth. In both figures, since the depth of the crack 2 is the same, there is no difference in the waveform of the ultrasonic wave blocked by the crack 2, so that the signal received by the second probe 13 in the situation of FIG. The signals received by the second probe 13 in the situation of FIG. 4 are substantially the same. That is, it is necessary to discriminate a good product (FIG. 3) and a defective product (FIG. 4) from the same signal.

  Here, the difference between the non-defective product of FIG. 3 and the defective product of FIG. 4 is the thickness of the mortar 1b. Therefore, in the present invention, the position of the gate is determined based on the thickness of the mortar 1b, and the non-defective product and the defective product are determined using the received signal within the gate period. The received signal outside this gate period is not used for diagnosis. The gate position can be defined as the time (start time) and judgment period (length) from when the ultrasonic wave is emitted until the diagnosis is started using the received signal, or the start time and the diagnosis is completed. It can also be defined as the time to finish (end time).

  FIG. 5 is a schematic diagram of a signal waveform in which the signal input from the first probe 12 is received by the second probe 13 in the situation of FIG. 3 and FIG. Show. In the figure, if the gate is applied to a position earlier in time (gate 1), the signal in the gate period becomes smaller. On the other hand, if the gate is applied to a position that is late in time (gate 2), the signal in the gate period increases. By making good use of this difference, it is possible to discriminate between good products and defective products.

  That is, using the relationship between the position of the gate and the received signal, for example, in the case of FIG. 3 where the thickness of the mortar 1b is thick, the gate is applied to a position (gate 2) later in time than FIG. In the case of FIG. 4 where the thickness of 1b is thin, the gate is hung at a position earlier in time (gate 1) than in FIG. That is, even when substantially the same signal is received, if the signal within the gate 2 determined by the thickness of the mortar 1b in FIG. If the signal in the gate 1 determined by the thickness of the mortar 1b in FIG. 4 is small, it can be determined as a defective product. A specific setting example of the position of the gate will be described by an experiment using a test specimen described later.

  The reception signal schematically shown in FIG. 5 is a signal obtained by scattering a pulse-like input signal by the aggregate 1d in the concrete 1a. The reception time of the scattered wave is received later than the signal received by following the path received by being reflected by the boundary surface 1c shown in FIG. In the present invention, the start position of the gate is set and used for determination with reference to the time when the ultrasonic wave propagates through the path shown in FIG. Hereinafter, the route used as the criterion is referred to as “boundary surface V route”. The length of the boundary surface V path becomes longer as the thickness of the mortar 1b becomes thicker, and the propagation time thereof becomes longer, so that the start position of the gate is delayed.

  Here, if the crack 2 is a defective product exceeding the thickness of the mortar 1b, it propagates along a path longer than the boundary surface V path, and the propagation time becomes longer, so that it is set based on the thickness of the mortar 1b. The signal reception start time is delayed from the start position of the gate. Further, not only the signal reception start time is delayed from the gate start position, but also the signal is scattered by the aggregate 1d in the concrete 1a, and as a result, the reception signal in the gate period becomes small. In addition, the aggregate 1d is not only one, but many exist in the concrete 1a. For this reason, scattering by the aggregate 1d is complicated, and multiple scattering occurs inside the concrete 1a. Therefore, as shown in FIG. 5, the received signal becomes complicated, and becomes a signal waveform having a relatively long duration rather than a pulse-like signal waveform like the input signal.

  Next, a diagnostic process for a specimen using a received signal within the gate period will be described.

  The first probe 12 radiates ultrasonic waves to the test body 1. The emitted ultrasonic wave propagates also inside the concrete 1a and is scattered by the internal aggregate 1d. The second probe 13 receives the ultrasonic waves that have been scattered and propagated, and converts them into electrical signals. The determination unit 15 receives the converted electric signal as a reception signal via the reception unit 14.

  Furthermore, the determination unit 15 determines the value of the maximum amplitude within the gate period of the received signal, for example, and compares these with a preset amplitude threshold value, thereby diagnosing the specimen. In addition, the amplitude threshold value used for the comparison may be set based on a value obtained in a portion where no crack is generated, or may be set by another method. An amplitude threshold calculated externally may be input to the determination unit 15 and set.

  Further, as a diagnostic method other than the comparison between the maximum amplitude value in the gate period and the amplitude threshold value, for example, a signal integral value in the gate period of the received signal is obtained, and these are compared with a preset integral threshold value. May be diagnosed. The integration threshold value used for comparison may be set based on a value obtained in a portion where no crack is generated, or may be set by another method. An integration threshold value calculated externally may be input to the determination unit 15 and set. Alternatively, the specimen may be diagnosed both by comparing the maximum amplitude value within the gate period of the received signal with the amplitude threshold value and comparing the signal integral value with the integral threshold value.

  In order to confirm the effectiveness of the present invention, a test body provided with a slit instead of a crack as an acoustic discontinuity was created and tested. FIG. 7 shows a sectional view of the slit specimen. The experiment was performed by installing the first probe 12 and the second probe 13 at a position sandwiching the slit. A probe having a center frequency of 500 kHz was used. As test specimens, slits 3 having depths of 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 40 mm and 50 mm were prepared.

  The specimens used in the experiment were prepared with a mortar 1b thickness of 20 mm. The distance between the probes was 40 mm. For this reason, the length of the interface V path is 56.6 mm. Further, considering the time delay (2.9 μs) in the response characteristic of the probe as the mortar sound velocity of 3600 m / s, the gate start position was set to 18.6 μs from these conditions. The gate width was 20 μs.

  FIG. 8 shows a waveform of a signal received by the second probe 13 using a test body in which the depth of the slit 3 is 5 mm, 10 mm, 15 mm, 20 mm, 25 mm, 30 mm, 40 mm, and 50 mm, and a gate. The period is also shown.

  FIG. 9 shows the relationship between the value of the maximum amplitude of the signal in the gate period and the slit depth. As can be seen from this figure, as the slit becomes deeper, the value of the maximum amplitude of the signal within the gate period also decreases. For example, if the amplitude threshold of the signal is set to −20 dB from a value obtained from a sound part (value of zero slit depth), a product having a slit depth of 25 mm or less can be roughly diagnosed as a good product.

  Thus, the value of the maximum amplitude of the signal within the gate period can be used for diagnosis of the specimen.

FIG. 10 shows the relationship between the signal integral value in the gate period and the slit depth. Here, energy is used as the signal integration value within the gate period. That is, assuming that the signal voltage is V and the resistance is R, Σ (V ² / R) is calculated, and this is defined as the signal integration value within the gate period. As can be seen from FIG. 10, as the slit becomes deeper, the energy within the gate period also decreases. For example, if the integral threshold value is set to −20 dB from a value obtained from a sound part (value of zero slit depth), a product having a slit depth of 25 mm or less can be roughly diagnosed as a good product. Note that the signal integration value within the gate period is not limited to energy. For example, the integrated value (Σ | V |) of the absolute value of the voltage may be used, or the integrated value of the absolute value of the voltage may be converted into an average value.

  As described above, the signal integration value within the gate period can be used for diagnosis of the specimen.

  Note that the diagnostic processing of the specimen may be performed using both diagnosis based on the maximum amplitude value of the signal within the gate period and diagnosis based on the signal integral value within the gate period.

  In the first embodiment, the thickness of the mortar 1b is known, the position of the gate is determined in advance, and the specimen is diagnosed. Therefore, if the thickness of the mortar 1b is known and the position of the gate can be determined in advance, the first probe 12 should be at least a transmission probe that can emit ultrasonic waves. Good. Alternatively, when the thickness of the mortar 1b is measured by another apparatus and information on the measured thickness of the mortar 1b is provided, the position of the gate can be determined in advance and set so that only ultrasonic waves can be emitted. Any credit probe is acceptable.

  As described above, according to the ultrasonic diagnostic apparatus according to Embodiment 1 of the present invention, the ultrasonic wave radiated to the test body in which the acoustic discontinuity occurs and propagated through the inside is received within the gate period. Because it is configured to determine the properties of the specimen from the ultrasonic information of the ultrasonic wave, it is possible to easily diagnose whether the acoustic discontinuity generated on the surface layer of the specimen is damage that affects the strength of the specimen. effective.

Embodiment 2. FIG.
In the ultrasonic diagnostic apparatus according to Embodiment 1 of the present invention, the case where the thickness of the mortar 1b is known and the position of the gate can be determined in advance has been described. In the second embodiment, an ultrasonic diagnostic apparatus that first determines the position of the gate after measuring the thickness of the mortar 1b when the thickness of the mortar 1b is not known will be described.

  In Embodiment 2, the reflected wave of the ultrasonic wave in the interface 1c of the concrete 1a and the mortar 1b is used for measuring the thickness of the mortar 1b. Hereinafter, this reflected wave is referred to as “boundary surface echo”.

  FIG. 11 is an explanatory diagram of boundary surface echoes. FIG. 12 is a diagram illustrating an example of a boundary echo that appears in a received wave confirmed in an experiment. First, the ultrasonic wave radiated from the first probe 12 propagates in the mortar 1b and is reflected by the boundary surface 1c. Next, the ultrasonic wave reflected by the boundary surface 1 c propagates again in the mortar 1 b and returns to the first probe 12. Therefore, if the first probe 12 is a transmission / reception probe, the reflected wave can be received by the first probe 12. Further, the thickness of the mortar 1b can be calculated from the time from the emission of ultrasonic waves to the detection of the boundary surface echo, the speed of sound propagating through the mortar 1b, and the like.

  FIG. 13 is a block diagram showing an example of an ultrasonic diagnostic apparatus according to Embodiment 2 of the present invention. As in the first embodiment, this ultrasonic diagnostic apparatus includes a transceiver 10, a first probe 12, and a second probe 13. The transceiver 10 includes a transmission unit 11, a reception unit 14, a determination unit 15, a display unit 16, and a control unit 21. In contrast to the configuration of the ultrasonic diagnostic apparatus according to the first embodiment, the first probe 12 is changed from the transmitting probe to the transmitting / receiving probe, so that the first probe 12 to the receiving unit 14 can be used. A signal line for sending a reception signal to is added. Each operation of the components functions and operates in the same manner as the components with the same reference numerals described in the first embodiment, and thus description thereof is omitted here.

  The first probe 12 receives an electrical signal from the transmitter 11, radiates an ultrasonic wave to the test body 1, receives a boundary surface echo reflected by the boundary surface 1 of the emitted ultrasonic wave, and receives this boundary surface. The echo is converted into an electric signal and transmitted to the receiving unit 14.

  The receiver 14 of the transceiver 10 receives the electrical signal converted by the first probe 12 and outputs it to the determination unit 15.

  The determination unit 15 of the transceiver 10 receives the electrical signal of the boundary surface echo from the reception unit 14, and based on the time difference from the emission of the ultrasonic wave by the first probe 12 to the reception of the boundary surface echo, the mortar 1b Measure the thickness. Further, the position of the gate is determined from the measured thickness of the mortar 1b, the distance between the first probe 12 and the second probe 13, the speed of sound propagating through the mortar 1b, and the like.

  The display unit 16 of the transceiver 10 includes not only the determination result of the determination unit 15 and the waveform of the ultrasonic wave received by the second probe 13, but also the waveform of the ultrasonic wave received by the first probe 12. Or the calculated thickness of the mortar 1b or the like.

  As described above, even when the thickness of the mortar 1b is not known, the ultrasonic diagnostic apparatus measures the thickness of the mortar 1b and determines the position of the gate based on the thickness of the mortar 1b. You can also. After determining the position of the gate, the processing may be performed in the same manner as in the ultrasonic diagnostic apparatus of the first embodiment to determine the properties of the specimen 1, and the description thereof is omitted here.

  In the second embodiment of the present invention, the ultrasonic diagnostic apparatus that measures the thickness of the mortar 1b using the interface echo has been described.

  In the first embodiment, the separate device described as an example of the configuration measures the thickness of the mortar 1b and supplies the thickness information to the ultrasonic diagnostic device. May be used to measure the thickness of the mortar 1b.

  As described above, according to the ultrasonic diagnostic apparatus according to the second embodiment of the present invention, as in the first embodiment, the radiation is radiated to the test body in which the acoustic discontinuity occurs, and is received by propagating through the inside. The ultrasonic discontinuity generated in the surface layer of the specimen is damage that affects the strength of the specimen because it is configured to determine the properties of the specimen from the ultrasonic information within the gate period. There is an effect that can be easily diagnosed.

  In addition, according to the ultrasonic diagnostic apparatus according to Embodiment 2 of the present invention, the position of the gate is set from the boundary surface echo received by the first probe for both transmission and reception, and the property of the specimen is determined. Thus, even if the thickness of the mortar 1b is not known, there is an effect that it is possible to easily diagnose whether the acoustic discontinuity generated on the surface layer of the specimen is damage affecting the strength of the specimen. .

  In the ultrasonic diagnostic apparatus of the present invention, the diagnosis of a test body having a two-layer structure in which concrete and mortar are combined has been described. However, the test body is not limited to the combination of concrete and mortar, and can be applied to diagnosis.

  DESCRIPTION OF SYMBOLS 1 Test body, 1a concrete, 1b mortar, 1c interface, 1d aggregate, 2 crack (acoustic discontinuity part), 3 slit, 10 transmitter / receiver, 11 transmission part, 12 1st probe, 13 2nd Probe, 14 receiver, 15 determination unit, 16 display unit, 21, 21a, 21b control unit, 31 transmitter, 32 receiver, 101 concrete specimen, 102 crack, 201 probe for transmission, 202 reception Probe for.

Claims (7)

A first probe disposed on the surface of the specimen where an acoustic discontinuity has occurred and emitting ultrasonic waves into the specimen;
It is arranged at a position on the surface of the test body that is paired with the first probe and sandwiches the acoustic discontinuity, and after being emitted from the first probe, A second probe for receiving the ultrasonic wave propagating through
A determination unit for determining a property of the test body in which the acoustic discontinuity occurs from ultrasonic information within a gate period among ultrasonic waves received by the second probe; Ultrasound diagnostic device. The first probe radiates into the specimen, receives ultrasonic waves reflected inside the specimen and propagated through the specimen,
The ultrasonic diagnostic apparatus according to claim 1, wherein the determination unit determines a position of the gate period from ultrasonic information received by the first probe. The first probe receives an ultrasonic wave reflected on a boundary surface of a layer constituting the test body,
The determination unit calculates a distance from the surface of the test body to the boundary surface from ultrasonic information received by the first probe, and determines the position of the gate period based on the calculated distance. The ultrasonic diagnostic apparatus according to claim 2, wherein the ultrasonic diagnostic apparatus is set.   The determination unit compares the value of the maximum amplitude of the ultrasonic wave within the gate period with a preset amplitude threshold value, and determines the property of the test specimen in which the acoustic discontinuity occurs. The ultrasonic diagnostic apparatus according to any one of claims 1 to 3, characterized in that:   The amplitude threshold is set on the basis of the value of the maximum amplitude of the ultrasonic wave in the gate period measured and received in a portion of the test body where the acoustic discontinuity does not occur. The ultrasonic diagnostic apparatus according to claim 4.   The determination unit compares the ultrasonic signal integration value within the gate period with a preset integration threshold value to determine the property of the specimen in which the acoustic discontinuity occurs. The ultrasonic diagnostic apparatus according to any one of claims 1 to 3.   The integration threshold is set with reference to a signal integration value of an ultrasonic wave in the gate period measured and received in a portion of the test body where the acoustic discontinuity does not occur. The ultrasonic diagnostic apparatus according to claim 6.

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