JP7564063B2 - Ultrasonic measurement device and ultrasonic measurement method - Google Patents

Description

The present invention relates to an ultrasonic measurement device and an ultrasonic measurement method for measuring the thickness of a concrete structure.

Ultrasonic measurement is a type of non-destructive measurement, and is used to measure the thickness of an object to be inspected. In more detail, ultrasonic waves are transmitted to the object to be inspected, and the reflected wave (bottom echo) reflected from the bottom surface of the object to be inspected is received. The thickness of the object to be inspected is calculated based on the reception time of the bottom echo (i.e., the propagation time of the ultrasonic waves).

Patent Document 1 discloses a method for improving the signal-to-noise ratio of the reflected wave (bottom echo) to the surface wave (noise). In Patent Document 1, while changing the distance between a transmitting probe and a receiving probe arranged on the surface of the object to be inspected, ultrasonic waves are transmitted by the transmitting probe, and the surface wave and the reflected wave are received by the receiving probe and converted into waveform signals, thereby obtaining multiple waveform signals according to the distance between the transmitting probe and the receiving probe. If the distance between the transmitting probe and the receiving probe is changed, the surface wave components in the waveform signal change significantly, whereas the reflected wave components do not change significantly. Therefore, it is possible to reduce the amplitude of the surface wave by performing a process of adding multiple waveform signals.

Japanese Patent Application Publication No. 09-061144

When ultrasonic measurement is used to measure the thickness of a concrete structure, scattered waves (scattered noise) are generated by the aggregates in the concrete structure, and the signal-to-noise ratio of the bottom echo to the scattered noise decreases. Therefore, it is conceivable to improve the signal-to-noise ratio of the bottom echo to the scattered noise by adopting the technology of Patent Document 1, for example. If the position of the transmitting probe or the receiving probe is changed, the scattered noise component in the waveform signal changes significantly, whereas the bottom echo component does not change significantly. Therefore, it is possible to reduce the amplitude of the scattered noise by performing a process of adding together multiple waveform signals.

However, in Patent Document 1, the process of adding up all the waveform signals is performed, which may result in a decrease in the signal-to-noise ratio. To explain in more detail, for example, if there are protrusions, depressions, or attachments on the surface of a concrete structure, the adhesion between the transmitting probe or receiving probe and the surface of the concrete structure is impaired, reducing the reception sensitivity of the receiving probe and decreasing the amplitude of the entire waveform signal. Therefore, if a process of adding up all the waveform signals is performed when waveform signals with reduced amplitudes are mixed, the signal-to-noise ratio will decrease.

The object of the present invention is to provide an ultrasonic measurement device and an ultrasonic measurement method that can improve the signal-to-noise ratio by selecting and processing multiple waveform signals.

In order to achieve the above object, a representative embodiment of the present invention is an ultrasonic measuring device comprising: a transmitting probe that is placed on the surface of a concrete structure and transmits ultrasonic waves; a receiving probe that is placed on the surface of the concrete structure and receives reflected waves and converts them into waveform signals; a moving device that changes the position of the transmitting probe and the position of the receiving probe on the surface of the concrete structure; and a signal processing device that records a plurality of waveform signals corresponding to combinations of the positions of the transmitting probe and the receiving probe, and selects and processes the plurality of waveform signals. In the apparatus, the signal processing device compares an integral value of the amplitude of a first waveform signal when the distance between the transmitting probe and the receiving probe is relatively short with an integral value of the amplitude of a second waveform signal when the distance between the transmitting probe and the receiving probe is relatively long, and includes the first waveform signal as a processing target when the integral value of the amplitude of the first waveform signal is greater than the integral value of the amplitude of the second waveform signal, but does not include the first waveform signal as a processing target when the integral value of the amplitude of the first waveform signal is smaller than the integral value of the amplitude of the second waveform signal.

According to the present invention, the signal-to-noise ratio can be improved by selecting and processing multiple waveform signals.

1 is a schematic diagram illustrating a configuration of an ultrasonic measurement device according to a first embodiment of the present invention. FIG. 2 is a diagram illustrating an arrangement of a transmitting probe and a receiving probe according to the first embodiment of the present invention. 3A to 3C are diagrams showing a plurality of waveform signals corresponding to combinations of positions of a transmitting probe and a receiving probe in the first embodiment of the present invention. FIG. 2 is a diagram showing the arrangement of a transmitting probe and a receiving probe in the first embodiment of the present invention, illustrating a case where the receiving sensitivity of the receiving probe is low. 4 is a flowchart showing a control procedure related to acquisition and selection of waveform signals in the first embodiment of the present invention. 4A to 4C are diagrams showing specific examples of a plurality of waveform signals in the first embodiment of the present invention, and also showing the relationship between the distance between the probes and the integral value of the amplitude of the waveform signals. 11A and 11B are diagrams illustrating a specific example of an addition signal in the first comparative example. 5A to 5C are diagrams illustrating specific examples of an addition signal in the first embodiment of the present invention. FIG. 11 is a schematic diagram illustrating a configuration of an ultrasonic measurement device according to a second embodiment of the present invention. FIG. 11 is a schematic diagram illustrating a structure of a moving mechanism of a moving device according to a second embodiment of the present invention. FIG. 11 is a diagram geometrically illustrating the propagation path of ultrasonic waves within a concrete wall in a second embodiment of the present invention. 13A and 13B are diagrams illustrating a specific example of an amplitude distribution image in the second comparative example. 13A to 13C are diagrams illustrating specific examples of amplitude distribution images according to the second embodiment of the present invention. 13 is a schematic diagram showing the shape of a concrete wall according to a modified example of the present invention together with a movement mechanism of a movement device. FIG.

The first embodiment of the present invention will be described with reference to the drawings.

Figure 1 is a schematic diagram showing the configuration of an ultrasonic measurement device in this embodiment. Figure 2 is a diagram showing the arrangement of a transmitting probe and a receiving probe in this embodiment. Figure 3 is a diagram showing multiple waveform signals corresponding to combinations of the positions of the transmitting probe and the receiving probe in this embodiment.

The ultrasonic measuring device of this embodiment measures the thickness of a concrete wall 2 erected on a floor 1. The ultrasonic measuring device of this embodiment includes a transmitting probe 11 and a receiving probe 12 arranged on the surface 3 of the concrete wall 2, a moving device 13A that changes the position of the transmitting probe 11 on the surface 3 of the concrete wall 2, a moving device 13B that changes the position of the receiving probe 12 on the surface 3 of the concrete wall 2, a moving control device 14 that controls the moving devices 13A and 13B, an ultrasonic flaw detector 15 that inputs and outputs signals between the transmitting probe 11 and the receiving probe 12, a signal processing device 16 connected to the moving control device 14 and the ultrasonic flaw detector 15 via wiring, and a display device 17 connected to the signal processing device 16 via wiring. The display device 17 is, for example, a display.

The moving device 13A has a running body that runs on the floor 1 in response to commands from the moving control device 14, and a support that is provided on the upper side of the running body and presses the transmitting probe 11 against the surface 3 of the concrete wall 2. It also has a running sensor (not shown) that detects state quantities related to the running of the running body, and outputs a detection signal of the running sensor to the moving control device 14.

Similarly, the moving device 13B has a running body that runs on the floor 1 in response to commands from the moving control device 14, and a support that is provided on the upper side of the running body and presses the receiving probe 12 against the surface 3 of the concrete wall 2. It also has a running sensor (not shown) that detects state quantities related to the running of the running body, and outputs a detection signal from the running sensor to the moving control device 14.

The movement control device 14 has a processor (not shown) that executes control according to a program, and a memory that stores programs and data. The movement control device 14 has, as its functional configuration, a movement control unit 18, a position calculation unit 19, and a distance calculation unit 20. The movement control unit 18 outputs commands to the movement devices 13A and 13B to control the position of the transmitting probe 11 and the receiving probe 12 on the surface 3 of the concrete wall 2.

The position calculation unit 19 of the movement control device 14 calculates the position of the transmitting probe 11 on the surface 3 of the concrete wall 2 based on the detection signal of the travel sensor of the movement device 13A, calculates the position of the receiving probe 12 on the surface 3 of the concrete wall 2 based on the detection signal of the travel sensor of the movement device 13A, and outputs it to the signal processing device 16. The distance calculation unit 20 calculates the distance between the transmitting probe 11 and the receiving probe 12 based on the positions of the transmitting probe 11 and the receiving probe 12, and outputs it to the signal processing device 16.

The ultrasonic flaw detector 15 has a pulser 21 and a receiver 22. The pulser 21 applies a voltage to the piezoelectric element of the transmitting probe 11 each time at least one of the positions of the transmitting probe 11 and the receiving probe 12 is changed, causing the transducer to transmit ultrasonic waves to the concrete wall 2. The piezoelectric element of the receiving probe 12 receives the reflected waves from the concrete wall 2, converts them into a waveform signal, and outputs it to the receiver 22. The receiver 22 digitally converts the waveform signal and outputs it to the signal processing device 16. The waveform signal indicates the change over time in the amplitude (intensity) of the reflected waves received by the receiving probe 12, based on the timing of transmission of ultrasonic waves by the transmitting probe 11.

Although not shown, the signal processing device 16 has a processor that executes control according to a program and a memory that stores programs and data. The signal processing device 16 records combinations of the positions of the transmitting probe 11 and the receiving probe 12, as well as the corresponding waveform signals and distances between the probes.

More specifically, positions _P1 , _P2 , _P3 , _P4 , _P5 , ..., Pk _-1 , _Pk are set at a predetermined interval ΔP in the horizontal direction (X direction) on the surface 3 of the concrete wall 2 (see FIG. 2). Then, the transmitting probe 11 is placed at position _P1 , and the receiving probe 12 is successively placed at positions _P2 , _P3 , _P4 , _P5 , ..., Pk _-1 , _Pk, to obtain and record corresponding waveform signals _W12 , _W13 , _W14 , _W15 , ..., W1 _(k-1) , _W1k . Thereafter, the transmitting probe 11 is placed at position _P2 , and the receiving probe 12 is successively placed at positions _P3 , _P4 , _P5 , ..., Pk _-1 , _Pk, thereby acquiring and recording the corresponding waveform signals _W23 , _W24 , _W25 , ..., W2 _(k-1) , _W2k . Note that the waveform signal W21 when the transmitting probe 11 is placed at position _P2 and the receiving probe 12 is placed at position _P1 is theoretically the same as the waveform signal _W12 when the transmitting probe 11 is placed at position _P1 and the receiving probe ₁₂ is placed at position _P2 , and is therefore not acquired. Furthermore, the waveform signals are acquired and recorded while changing the combination of the positions of the transmitting probe 11 and the receiving probe 12. Finally, transmitting probe 11 is placed at position P _k−1 and receiving probe 12 is placed at position P _k to acquire and record waveform signal W _(k−1)k .

Each waveform signal contains not only reflected waves (bottom echoes) reflected by the bottom surface 4 of the concrete wall 2 as shown by the solid arrows in FIG. 2, but also scattered waves (scattered noise) scattered by the aggregate 5 inside the concrete wall 2 as shown by the dotted arrows in FIG. 2. Therefore, the signal processing device 16 performs processing to add up multiple waveform signals to generate a sum signal. This reduces the amplitude of the scattered noise in the sum signal, improving the signal-to-noise ratio of the bottom echo. Then, the reception time of the bottom echo is extracted from the sum signal, and the thickness of the concrete wall 2 is calculated based on this.

If the signal processing device were to add up all the waveform signals, the S/N ratio would likely decrease. To explain in more detail, for example, if there are protrusions 6, depressions 7, or deposits 8 on the surface 3 of the concrete wall 2 as shown in Figures 4(a) to 4(c), the adhesion between the transmitting probe 11 or the receiving probe 12 and the surface 3 of the concrete wall 2 would be impaired, and the receiving sensitivity of the receiving probe 12 would decrease, causing the amplitude of the entire waveform signal to decrease. Also, for example, as shown in Figure 4(d), if aggregate 5 in the concrete wall 2 is biased toward the propagation path of the ultrasonic waves, the receiving sensitivity of the receiving probe 12 would decrease, causing the amplitude of the entire waveform signal to decrease. Therefore, if a process of adding up all the waveform signals is performed in a state where waveform signals with reduced amplitudes are mixed, the S/N ratio would decrease.

The signal processing device 16 of this embodiment is therefore designed to improve the signal-to-noise ratio by selecting and processing a plurality of waveform signals. The signal processing device 16 has, as its functional configuration, a waveform signal recording unit 23, an integral value calculation unit 24, a signal selection unit 25, and a signal processing unit 26. The waveform signal recording unit 23 records combinations of the positions of the transmitting probe 11 and the receiving probe 12, as well as the corresponding waveform signals and the distance between the probes. The integral value calculation unit 24 calculates the integral value of the amplitude of each waveform signal, and causes the waveform signal recording unit 23 to record it.

The signal selection unit 25 of the signal processing device 16 sequentially selects, from among the multiple waveform signals recorded by the waveform signal recording unit 23, a first waveform signal when the distance between the probes is relatively short and a second waveform signal when the distance between the probes is relatively long, and compares the integral values of their amplitudes. When the integral value of the amplitude of the first waveform signal is greater than the integral value of the amplitude of the second waveform signal, it is determined that the receiving sensitivity of the receiving probe 12 is normal, and the first waveform signal is included in the processing target. On the other hand, when the integral value of the amplitude of the first waveform signal is smaller than the integral value of the amplitude of the second waveform signal, it is determined that the receiving sensitivity of the receiving probe 12 has decreased, and the first waveform signal is not included in the processing target.

The signal processing unit 26 of the signal processing device 16 performs processing to add up the multiple waveform signals to be processed, and generates an added signal. Then, the reception time of the bottom echo is extracted from the added signal, and the thickness of the concrete wall 2 is calculated based on this. The display 17 displays, for example, the added signal and the thickness of the concrete wall 2.

Next, details of the control related to the acquisition and selection of waveform signals in this embodiment will be described. FIG. 5 is a flowchart showing the procedure of the control related to the acquisition and selection of waveform signals in this embodiment. FIG. 6(a) to FIG. 6(d) show specific examples of multiple waveform signals in this embodiment, and FIG. 6(e) is a diagram showing the relationship between the distance between the probes and the integral value of the amplitude of the waveform signal.

First, in step S1, the signal processing device 16 initializes an identifier m corresponding to the position of the transmitting probe 11 (m=1), and in step S2, the moving device 13A sets the transmitting probe 11 to position _P1 .

In step S3, the signal processing device 16 initializes an identifier n corresponding to the position of the receiving probe 12 (n=(m+1), initially n=2), and in step S4, the moving device 13B sets the receiving probe 12 to position _P2 .

Proceeding to steps S5 and S6, the signal processing device 16 acquires a waveform signal _W12 (see FIG. 6(a)) corresponding to the combination of the position _P1 of the transmitting probe 11 and the position _P2 of the receiving probe 12, calculates the integral value _A12 of the amplitude, and records them. At this point, since there is only one waveform signal, steps S7 to S10 are skipped and the process moves to step S11.

In step S11, the signal processing device 16 changes the identifier n (n=3), and in step S4, the moving device 13B sets the receiving probe 12 to position _P3 .

Proceeding to steps S5 and S6, signal processing device 16 acquires waveform signal _W13 (see FIG. 6(b)) corresponding to the combination of position _P1 of transmitting probe 11 and position _P3 of receiving probe 12, calculates the integral value _A13 of its amplitude, and records them. Proceeding to step S7, signal processing device 16 compares the integral value A12 of the amplitude of waveform signal _W12 when the distance between the probes is ΔP with the integral value _A13 of the amplitude of waveform signal W13 when the distance between the probes is (ΔP×2). Then, if the integral value _A12 of the amplitude of waveform signal W12 is greater than the integral value _A13 of the amplitude of waveform signal _W13 , as shown in FIG. ₆ (e ₎ , for example, the process proceeds to step _S8 , where waveform signal _W12 is included in the processing target.

Proceeding to step S10, the signal processing device 16 determines whether or not the number of waveform signals to be processed when the transmitting probe 11 is placed at position _P1 has reached a predetermined threshold (e.g., (k-1)). At this point, the number of waveform signals has not reached the predetermined threshold, so the process proceeds to step S11.

In step S11, the signal processing device 16 changes the identifier n (n=4), and in step S4, the moving device 13B sets the receiving probe 12 to position _P4 .

Proceeding to steps S5 and S6, signal processing device 16 acquires waveform signal _W14 (see FIG. 6(c)) corresponding to the combination of position _P1 of transmitting probe 11 and position _P4 of receiving probe 12, calculates amplitude integral value _A14 , and records them. Proceeding to step S7, signal processing device 16 compares amplitude integral value A13 of waveform signal _W13 when the distance between the probes is (ΔP×2) with amplitude integral value A14 of waveform signal _W14 when the distance between the probes is (ΔP×3). Then, if amplitude integral _{value A13} of waveform signal _W13 is smaller than amplitude integral value _A14 of waveform signal _W14 , for example as shown in FIG. 6(e ₎ , then the process proceeds to step S9, and waveform signal _W13 is not included in the processing target.

The process proceeds from step S10 to step S11, where the signal processing device 16 changes the identifier n (n=5), and in step S4, the moving device 13B sets the receiving probe 12 to position _P5 .

Proceeding to steps S5 and S6, signal processing device 16 acquires waveform signal _W15 (see FIG. 6(d)) corresponding to the combination of position _P1 of transmitting probe 11 and position _P5 of receiving probe 12, calculates the integral value _A15 of its amplitude, and records them. Proceeding to step S7, signal processing device 16 compares the integral value A14 of the amplitude of waveform signal _W14 when the distance between the probes is (ΔP×3) with the integral value _A15 of the amplitude of waveform signal _W15 when the distance between the probes is (ΔP×4). Then, if the integral value _A14 of the amplitude of waveform signal _W14 is greater than _the integral value _A15 of the amplitude of waveform signal _W15 , as shown in FIG. 6(e), for example, the process proceeds to step S7, and waveform signal _W15 is included in the processing target.

The above-mentioned steps S4 to S11 are repeated (description omitted). Note that the waveform signal _W1k corresponding to the combination of the position P1 of the transmitting probe ₁₁ and the position _Pk of the receiving probe 12 is included in the processing target without performing the judgment of step S7. As described above, if the waveform signal _W13 is not included in the processing target, the number of waveform signals to be processed when the transmitting probe 11 is placed at the position _P1 does not reach the predetermined threshold. Therefore, even after the waveform signal _W1k is acquired and recorded, the process proceeds to step S11 via step S10.

In step S11, the signal processing device 16 changes the identifier n (n=3'), and in step S4, the moving device 13B sets the receiving probe 12 to position P3 _' . That is, a combination of the position of the transmitting probe 11 and the position of the receiving probe 12 is added. Note that position P3 _' is between position _P3 and position _P4 or _P2 .

Proceeding to steps S5 and S6, signal processing device 16 acquires waveform signal W13 _' (not shown) corresponding to the combination of position _P1 of transmitting probe 11 and position P3 _' of receiving probe 12, calculates the integral value _A13' of the amplitude, and records them. Proceeding to step S7, signal processing device 16 compares the integral value _A13' of the amplitude of waveform signal W13 _' when the distance between the probes is relatively short with the integral value _A14 of the amplitude of waveform signal _W14 when the distance between the probes is relatively long. Then, for example, as shown in Fig. 6(e), if the integral value A13 _' of the amplitude of waveform signal W13 _' is larger than the integral value _A14 of the amplitude of waveform signal _W14 , proceeding to step S8, waveform signal W13 _' is included as a processing target. As a result, the number of waveform signals to be processed when transmitting probe 11 is placed at position _P1 reaches a predetermined threshold value. Therefore, the process proceeds to step S12 via step S10.

In step S12, the signal processing device 16 determines whether or not the movement of the transmitting probe 11 is complete, that is, whether or not the transmitting probe 11 is set to position P _k−1 . At this point, the movement of the transmitting probe 11 is not complete, so the process proceeds to step S13.

In step S13, the signal processing device 16 changes the identifier m (m=2), and in step S2, the moving device 13A sets the transmitting probe 11 to position _P2 . Thereafter, the above-mentioned procedure is repeated (description is omitted).

If the movement of the transmitting probe 11 is completed in step S12, that is, if the transmitting probe 11 is set to position P _k-1 , this control ends. Thereafter, the signal processing device 16 performs a process of adding up the multiple waveform signals to be processed (more specifically, the waveform signals W ₁₂ , W _13′ , W ₁₄ , W _15, etc.).

As described above, in this embodiment, the S/N ratio can be improved by selecting and processing multiple waveform signals. Furthermore, when the number of waveform signals to be processed does not reach a predetermined threshold, the S/N ratio can be improved by adding combinations of the positions of the transmitting probe 11 and the receiving probe 12 and acquiring the corresponding waveform signals.

Figure 7 shows a specific example of the sum signal in the first comparative example (more specifically, when all waveform signals are processed while waveform signals with reduced amplitudes are mixed in). Figure 8 shows a specific example of the sum signal in this embodiment. As is clear from these figures, this embodiment can improve the signal-to-noise ratio.

The second embodiment of the present invention will be described with reference to the drawings. In this embodiment, parts equivalent to those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

Figure 9 is a schematic diagram showing the configuration of an ultrasonic measurement device in this embodiment. Figure 10 is a schematic diagram showing the structure of a movement mechanism of a movement device in this embodiment.

In place of the moving devices 13A and 13B, the ultrasonic measurement device of this embodiment is equipped with a moving device 13 that changes the position of the transmitting probe 11 and the receiving probe 12 on the surface 3 of the concrete wall 2.

The moving device 13 includes a pair of running bodies 27A, 27B that run on the floor 1 in response to commands from the moving control device 14, a fixed frame 28 that is installed between the running bodies 27A, 27B and extends in the horizontal direction (X direction) along the surface 3 of the concrete wall 2, a moving mechanism 29A that is provided on the fixed frame 28 and moves the transmitting probe 11 in response to commands from the moving control device 14, and a moving mechanism 29B that is provided on the fixed frame 28 and moves the receiving probe 12 in response to commands from the moving control device 14.

The movement mechanism 29A is composed of a circular belt 30A rotatably mounted on the fixed frame 28, a motor 31A that rotates the belt 30A in response to a command from the movement control device 14, a holder 32A that moves laterally (X direction) as the belt 30A rotates, a screw 33A screwed into a screw hole in the holder 32A, a spring (not shown) that biases the screw 33A in a direction toward the surface of the concrete wall 2 (Z direction), and a gimbal 34A that is provided at the tip of the screw 33A and holds the transmitting probe 11.

Similarly, the movement mechanism 29B is composed of a circular belt 30B rotatably mounted on the fixed frame 28, a motor 31B that rotates the belt 30B in response to a command from the movement control device 14, a holder 32B that moves laterally (X direction) as the belt 30B rotates, a screw 33B screwed into a screw hole in the holder 32B, a spring (not shown) that biases the screw 33B in a direction toward the surface of the concrete wall 2 (Z direction), and a gimbal 34B that is provided at the tip of the screw 33B and holds the receiving probe 12.

The moving device 13 has a running sensor (not shown) that detects state quantities related to the running of the running bodies 27A and 27B, a motor sensor 35A that detects the amount of rotation of the motor 31A, a motor sensor 35B that detects the amount of rotation of the motor 31B, a screw sensor 36A that detects the amount of rotation of the screw 33A, and a screw sensor 36B that detects the amount of rotation of the screw 33B, and outputs detection signals of the running sensor, motor sensors 35A and 35B, and screw sensors 36A and 36B to the moving control device 14.

The movement control unit 18 of the movement control device 14 outputs a command to the movement device 13 to control the position of the transmitting probe 11 and the receiving probe 12 on the surface 3 of the concrete wall 2. The position calculation unit 19 calculates the position of the transmitting probe 11 on the surface 3 of the concrete wall 2 based on the detection signals of the travel sensor, motor sensor 35A, and screw sensor 36A, and calculates the position of the receiving probe 12 on the surface 3 of the concrete wall 2 based on the detection signals of the travel sensor, motor sensor 35B, and screw sensor 36B, and outputs the position to the signal processing device 16.

As in the first embodiment, the waveform signal recording unit 23 of the signal processing device 16 records the combination of the position of the transmitting probe 11 and the position of the receiving probe 12, as well as the corresponding waveform signal and the distance between the probes. The integral value calculation unit 24 calculates the integral value of the amplitude of each waveform signal and causes the waveform signal recording unit 23 to record it.

As in the first embodiment, the signal selection unit 25 of the signal processing device 16 sequentially selects, from among the multiple waveform signals recorded by the waveform signal recording unit 23, a first waveform signal when the distance between the probes is relatively short and a second waveform signal when the distance between the probes is relatively long, and compares the integral values of their amplitudes. Then, when the integral value of the amplitude of the first waveform signal is greater than the integral value of the amplitude of the second waveform signal, it is determined that the receiving sensitivity of the receiving probe 12 is normal, and the first waveform signal is included in the processing target. On the other hand, when the integral value of the amplitude of the first waveform signal is smaller than the integral value of the amplitude of the second waveform signal, it is determined that the receiving sensitivity of the receiving probe 12 has decreased, and the first waveform signal is not included in the processing target.

The signal processing unit 26A of the signal processing device 16 extracts and adds the corresponding amplitudes of the multiple waveform signals to be processed for each position within the concrete wall 2, to generate an amplitude distribution image (full matrix capture method).

A method for calculating the amplitude (added value) at position p in the concrete wall 2 will be described. As shown in Fig. 11, it is assumed that the transmitting probe 11 is placed at position _Pm , the receiving probe 12 is placed at position _Pn , and ultrasonic waves from the transmitting probe 11 are reflected at position p and received by the receiving probe 12. The position _Pm of the transmitting probe 11 is defined by coordinates ( _xm , _zm ) in the XZ coordinate system, the position _Pn of the receiving probe 12 is defined by coordinates ( _xn , _zn ) in the XZ coordinate system, and the position p is defined by coordinates (r, θ) in the polar coordinate system.

The propagation distance r _m of the ultrasonic wave from the transmitting probe 11 to the position p is given by the following formula (1). Moreover, the propagation distance r _n of the ultrasonic wave from the position p to the receiving probe 12 is given by the following formula (2). Therefore, the propagation time τ _mn of the ultrasonic wave from the transmitting probe 11 to the receiving probe 12 is given by the following formula (3). Note that c in the formula is the speed of sound in the concrete wall.

The amplitude (added value) S at position p in the concrete wall 2 is given by the following equation (4). That is, for each waveform signal, the amplitude at the propagation time corresponding to position p in the concrete wall 2 is extracted and added up. However, as shown in the above-mentioned FIG. 3, some waveform signals (more specifically, waveform signals _W11 , _W21 , _W22 , _W31 , _W32 , _W33 , ..., _Wkk ) do not exist, so these are excluded. Then, an amplitude distribution image showing the amplitude at each position p by brightness or the like is generated and displayed on display 17.

In this embodiment, as in the first embodiment, the S/N ratio can be improved by selecting and processing multiple waveform signals. Also, as in the first embodiment, when the number of waveform signals to be processed does not reach a predetermined threshold, the S/N ratio can be improved by adding combinations of the positions of the transmitting probe 11 and the receiving probe 12 and acquiring the corresponding waveform signals.

Figure 12 shows a specific example of an amplitude distribution image in the second comparative example (more specifically, when all waveform signals are processed while some waveform signals have reduced amplitudes). Figure 13 shows a specific example of an amplitude distribution image in this embodiment. As is clear from these figures, this embodiment can improve the signal-to-noise ratio.

In the first and second embodiments, the concrete structure to be measured is described as a concrete wall 2 that does not have a curvature, but the present invention is not limited to this. For example, as shown in FIG. 14, the concrete structure may be a concrete wall 2 that has a curvature. Also, the concrete structure may be a concrete structure other than the concrete wall 2.

2 concrete wall 3 surface 11 transmitting probe 12 receiving probe 13, 13A, 13B moving device 16 signal processing device

Claims (8)

a transmitting probe that is placed on the surface of the concrete structure and transmits ultrasonic waves;
a receiving probe disposed on the surface of the concrete structure, receiving the reflected wave and converting it into a waveform signal;
a moving device that changes the position of the transmitting probe and the position of the receiving probe on the surface of the concrete structure;
a signal processing device that records a plurality of waveform signals corresponding to combinations of positions of the transmitting probe and the receiving probe, and selects and processes the plurality of waveform signals,
The signal processing device includes:
comparing an integral value of the amplitude of a first waveform signal when the distance between the transmitting probe and the receiving probe is relatively short with an integral value of the amplitude of a second waveform signal when the distance between the transmitting probe and the receiving probe is relatively long;
an ultrasonic measuring device comprising: an ultrasonic measuring unit that includes the first waveform signal as a processing target when an integral value of the amplitude of the first waveform signal is greater than an integral value of the amplitude of the second waveform signal; and that does not include the first waveform signal as a processing target when the integral value of the amplitude of the first waveform signal is smaller than the integral value of the amplitude of the second waveform signal. 2. The ultrasonic measuring device according to claim 1,
The ultrasonic measuring device is characterized in that, when the number of waveform signals to be processed does not reach a predetermined threshold, the signal processing device adds a combination of the position of the transmitting probe and the position of the receiving probe to obtain a corresponding waveform signal. 2. The ultrasonic measuring device according to claim 1,
The ultrasonic measuring device is characterized in that the signal processing device performs processing for adding up a plurality of waveform signals to be processed. 2. The ultrasonic measuring device according to claim 1,
The ultrasonic measuring device is characterized in that the signal processing device performs processing to extract and add corresponding amplitudes of multiple waveform signals to be processed for each position within the concrete structure, thereby generating an amplitude distribution image. 1. An ultrasonic measurement method comprising: transmitting ultrasonic waves from a transmitting probe while changing positions of a transmitting probe and a receiving probe on a surface of a concrete structure; receiving reflected waves from the transmitting probe and converting the reflected waves into waveform signals; acquiring a plurality of waveform signals corresponding to combinations of positions of the transmitting probe and the receiving probe; and selecting and processing the plurality of waveform signals;
comparing an integral value of the amplitude of a first waveform signal when the distance between the transmitting probe and the receiving probe is relatively short with an integral value of the amplitude of a second waveform signal when the distance between the transmitting probe and the receiving probe is relatively long;
an ultrasonic measurement method comprising: when an integral value of the amplitude of the first waveform signal is greater than an integral value of the amplitude of the second waveform signal, the first waveform signal is included as a processing target; and when the integral value of the amplitude of the first waveform signal is smaller than the integral value of the amplitude of the second waveform signal, the first waveform signal is not included as a processing target. The ultrasonic measurement method according to claim 5,
An ultrasonic measurement method characterized in that, when the number of waveform signals to be processed does not reach a predetermined threshold, a combination of the position of the transmitting probe and the position of the receiving probe is added to obtain a corresponding waveform signal. The ultrasonic measurement method according to claim 5,
An ultrasonic measuring method characterized by performing a process of adding up a plurality of waveform signals to be processed. The ultrasonic measurement method according to claim 5,
An ultrasonic measurement method comprising the steps of: extracting and adding amplitudes corresponding to a plurality of waveform signals to be processed for each position within the concrete structure; and generating an amplitude distribution image.

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