JPH06308105A - Ultrasonic inspecting method and apparatus - Google Patents

Abstract

PURPOSE:To negate influences by the multiple reflection within a lens, by processing signals without using a plurality of ultrasonic vibrators. CONSTITUTION:A detecting signal from an ultrasonic probe 20 is divided into a pair of detecting/distributing signals by a distributer 26. One of the signals is delayed a predetermined amount by a delay circuit 29, and the level of the signal is adjusted by a level adjusting circuit 30. The differece of the pair of detecting signals is obtained by an operational circuit 28. Accordingly, a signal multi-reflected within an acoustic lens 21 is removed from the detecting signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic inspection method and apparatus capable of canceling the influence of multiple reflections in an acoustic lens.

[0002]

2. Description of the Related Art FIG. 7 is a diagram showing a conventional example of this type of ultrasonic inspection apparatus (see Japanese Patent Laid-Open No. 162162/1990).
In this figure, reference numeral 1 is an ultrasonic probe, which is in contact with the upper surface of the subject 3 via a medium (for example, water) 2.

An ultrasonic probe 1 is constructed by housing a diaphragm 5 and a lens 6 at one end of a case 4 having a predetermined shape, and a diaphragm 7 and a lens 8 having the same shape and characteristics at the other end. Has been done. The diaphragm 5 and the lens 6 are the first ultrasonic probe U.
P1 and the diaphragm 7 and the lens 8 constitute a second ultrasonic probe UP2, and the first ultrasonic probe UP1 directs an ultrasonic beam toward the subject 3 via the medium 2. And the second ultrasonic probe UP2 is installed so as to irradiate the ultrasonic signal into the air which is the dummy irradiation target.

Reference numerals 9 and 10 respectively denote a circulator for flowing a signal only in the directions indicated by arrows, 11 denotes a transmitter for generating an excitation pulse, 12 denotes a receiver, and the receiver 12 has output terminals a and b.
Is connected to each of the ultrasonic probes UP1 and UP2. As shown in FIG. 8, the receiver 12 inverts the polarity of the output signal from the output terminal b and adjusts the level due to the difference in the acoustic impedance of the air and the medium 2, and the code converter 13. And an adder 14 for adding the output of the adder 13 and the output signal from the output terminal a. The output of the adder 14 is output via the output terminal c.

The operation of the above configuration will be described below with reference to the waveform chart of FIG. First, when the excitation pulse is input to each of the ultrasonic probes UP1 and UP2, the diaphragms 5 and 7 simultaneously generate ultrasonic waves. The ultrasonic waves generated by the diaphragm 5 are applied to the subject 3 through the lens 6 and are reflected by the exit of the lens 6, the surface of the subject 3 and the defect 15 to obtain ultrasonic echo signals P _L , P _s. , P _f are received by the diaphragm 5 via the lens 6, and the received signal is output from the output terminal a. On the other hand, the ultrasonic wave generated by the diaphragm 7 is irradiated into the air through the lens 8 and the pseudo echo signal P _L obtained by being reflected at the exit of the lens 8 is received by the diaphragm 7 through the lens 8. The received signal is output from the output terminal b.

The pseudo echo signal from the output terminal b has its polarity inverted by the code converter 13 and is subjected to level adjustment value correction and the like, and is input to the adder 14. As a result, the echo signal as shown in FIGS. 9A and 9B is input to the adder 14. Here, P _p and −P _p are excitation pulses applied to the vibrating plates 5 and 7, P _{L1 to} P _L3 are echo signals multiple-reflected in the lens 6, and −P _L1 to −P _L3 are in the lens 8. Is reflected by the code converter 13 and the polarity is inverted by the code converter 13, P _s is the echo signal reflected on the surface of the subject 3, and P _f ′ is from the defect 15 containing the in-lens multiple reflection component P _L2 . Is an echo signal, P _p and −P _p ,
P _L1 and -P _L1, P _L2 and -P _L2, P _L3 and -P _L3 respectively the same phase is at the same level, the polarity becomes opposite.

Therefore, when such an echo signal is added by the adder 14, the echo signals due to the multiple reflections in the lens are canceled by each other with the same phase, as shown in FIG. 9C. Only the echo signals P _s and P _f reflected from the surface 15 and the defect 15 inside thereof remain and are output from the output terminal c of the adder 14. That is, the echo signal P _f from the defect 15 is extracted in a form that does not include multiple reflection components in the lens. This is extracted without being affected by the multiple reflection in the lens even if the distance between the lens 5 and the subject 3 or the thickness of the medium 2 changes. This makes it possible to obtain accurate information on the defect 15.

[0008]

However, in the above-mentioned conventional ultrasonic inspection apparatus, one of the pair of ultrasonic probes UP1 and UP2 having the same characteristics is directed toward the subject 3 and the ultrasonic probe UP1 is turned on. Signals from the specimen 3 and the lens 5 are obtained, the other ultrasonic probe UP2 is directed to the air, and a signal from the lens 6 is obtained, and the in-lens multiple reflection component is canceled by the pair of signals. It is difficult to manufacture a pair of ultrasonic probes UP1 and UP2 having exactly the same acoustic characteristics with the current technology, and there is a problem that the ultrasonic probe 1 as a whole becomes large. .

It is an object of the present invention to provide an ultrasonic inspection method and apparatus capable of canceling the influence of multiple reflection in a lens by signal processing without using a plurality of ultrasonic transducers.

[0010]

An embodiment of the invention of claim 1 will be described with reference to FIG. 1 showing an embodiment.
1 and is applied to an ultrasonic inspection method using the ultrasonic probe 20 that transmits and receives ultrasonic waves to and from the subject 23.
The above-mentioned object is to divide the reception signal from the ultrasonic probe 20 into a pair of reception distribution signals, and to delay one of the reception distribution signals with a predetermined delay by the delay means 29, thereby adjusting the level adjusting means. This is achieved by adjusting the level of the pair of reception distribution signals by 30 and obtaining the difference between the pair of reception distribution signals by the subtracting means 28, and removing the signal multi-reflected in the acoustic lens 21 from the reception signal. To be done. The invention according to claim 2 includes an acoustic lens 21, and an ultrasonic probe 2 for transmitting and receiving ultrasonic waves to and from a subject 23.
0 is applied to the ultrasonic inspection apparatus, and the above-mentioned purpose is to divide the reception signal from the ultrasonic probe 20 into a pair of reception distribution signals, and one of the reception distribution signals. Delay means 29 for giving a predetermined delay to a signal
And level adjustment means 30 for adjusting the level of the pair of received distribution signals, and subtraction means 28 for obtaining the difference between the pair of received distribution signals. Here, the delay setting means 31 for variably setting the delay time given by the delay means 29, and the level adjusting means 3
Level setting means 32 for variably setting the level of the reception distribution signal adjusted by 0 may be provided. According to a fourth aspect of the present invention, the received signal from the ultrasonic probe 20 is stored in the storage means as received data, the delay means gives a predetermined delay to the received data, and the level adjusting means gives the received data. The reference data by adjusting the level of, the difference between the received data and the reference data by subtraction means, by an ultrasonic inspection method such as removing the signal multiple reflected in the acoustic lens from the received data, The above-mentioned purpose is achieved. Further, in the invention of claim 5, the received signal from the ultrasonic probe 20 is stored in the storage means as received data, and the multiple reflected signal which is multiple-reflected in the acoustic lens 22 by the extracting means, and An interference signal in which a multiple reflection signal and a signal to be inspected interfere with each other is extracted from the received data, a level adjusting unit adjusts the levels of the multiple reflection signal and the interference signal, and a subtracting unit adjusts the multiple reflection signal and the interference signal. The above object is achieved by an ultrasonic inspection method in which the difference from the interference signal is obtained and the multiple reflection signal is removed from the received data.

[0011]

[Action]

-Claim 1-The delay means 29 gives a predetermined delay to one of the reception distribution signals, and the level adjusting means 30 adjusts the levels of the pair of reception distribution signals. The signal multiple-reflected in the acoustic lens 21 is received at a predetermined time interval and is attenuated as the number of reflections increases. Therefore, the delay means 29 delays one reception distribution signal by the time interval described above. By adjusting the attenuation amount of the signal by the level adjusting means 30 and obtaining the difference between the pair of reception distribution signals by the subtracting means 28, the signal multiply reflected in the acoustic lens 21 can be removed from the reception signal. -Claim 4 The delay means is the ultrasonic probe 20 stored in the storage means.
Gives a predetermined delay to the received data which is the received signal from
The level adjusting means adjusts the level of the received data and uses it as reference data. The signal multiple-reflected in the acoustic lens 21 is received at a predetermined time interval and is attenuated as the number of reflections increases. Therefore, the delay means delays the received data by the time interval described above, and the level adjusting means. If the attenuation of the signal is adjusted by 30 and the difference between the received data and the reference data is obtained by the subtracting means, the signal multiply reflected in the acoustic lens 21 can be removed from the received data. According to a fifth aspect of the present invention, the extracting means stores the multiple reflection signal which is multiple reflected in the acoustic lens 22 and the interference signal in which the multiple reflection signal interferes with the inspection target signal, in the storage means. Extracted from the reception data which is the reception signal from 20, the level adjusting means adjusts the levels of the multiple reflection signal and the interference signal. The signal multiple-reflected in the acoustic lens 21 is received at a predetermined time interval and is attenuated as the number of reflections increases. Therefore, the level adjusting unit 30 adjusts the signal attenuation and the subtracting unit multiple-reflects. The multiple reflection signal can be removed from the received data by determining the difference between the signal and the interference signal.

Incidentally, in the section of means and action for solving the above problems for explaining the constitution of the present invention, the drawings of the embodiments are used for the purpose of making the present invention easy to understand. It is not limited to.

[0013]

【Example】

First Embodiment FIG. 1 is a block diagram showing an ultrasonic flaw detector which is a first embodiment of the ultrasonic inspection apparatus according to the present invention. In this figure, reference numeral 20 denotes an ultrasonic probe, and an ultrasonic transducer 22 is provided on the upper surface 21a of the acoustic lens 21, and ultrasonic waves generated by the ultrasonic transducer 22 and propagated in the acoustic lens 21 are generated. The concave curved surface 21b provided at the lower part of the concave portion 21b focuses the light and irradiates the subject 23 with the light. The subject 23 has a defect 35 near the surface thereof. 24
Is a transmitter that generates a pulse for exciting the ultrasonic transducer 22, and 25 is a circulator that sends a signal only in the direction shown by the arrow in the figure.

The reception signal received by the ultrasonic transducer 22 is distributed to the two reception lines 27a and 27b by the distributor 26 via the circulator 25. One receiving line 27a is directly connected to the A port of the subtracting circuit 28, and the other receiving line 27b is provided with a delay circuit 29 and a level adjusting circuit 30 and is connected to the B port of the subtracting circuit 28. The delay circuit 29 gives a predetermined delay to the reception signal flowing through the reception line 27b, and the level adjustment circuit 30
Similarly, the received signal flowing through the receiving line 27b is amplified and its level is adjusted. Normally, the ultrasonic signal is transmitted to the acoustic lens 2.
The level adjusting circuit 30 preferably includes a logarithmic amplifier, because its intensity exponentially attenuates when propagating in 1. The delay time provided by the delay circuit 29 and the amplification factor of the attenuator 30 are variably set by the delay time setting circuit 31 and the level setting circuit 32, respectively.

The subtraction circuit 28 outputs the difference between the signals input to the pair of ports A and B. The amplifier 33 amplifies the output of the subtraction circuit 28. This output is processed by a well-known image processing circuit or the like located in the subsequent stage. Reference numeral 34 is a waveform observing device such as an oscilloscope that monitors the input signals to the ports A and B of the subtraction circuit 28 and the output signal of the subtraction circuit 28.

Next, the operation of the ultrasonic flaw detector according to this embodiment will be described with reference to the waveform diagrams of FIGS. The transmitter 24 generates a pulse for exciting the ultrasonic probe 20, and the pulse is input to the ultrasonic transducer 22 of the probe 20 via the circulator 25. The oscillator 22 is excited by the pulse to generate an ultrasonic wave, and the ultrasonic wave propagates through the acoustic lens 21 and is irradiated toward the subject 23. As shown in FIG. 3, the surface echo of the surface of the subject 23, the surface echo P _s reflected by the defect 35, and the defect echo P _f are received by the ultrasonic transducer 22 following the above-mentioned propagation paths in reverse. at the same time,
The multi-reflected waves P _L1 and P _L2 (hereinafter also referred to as P _L in some cases) reflected at the interface of the concave curved surface 21 b of the acoustic lens 21 are also received by the ultrasonic transducer 22. Although only the double reflected wave P _L2 is shown in FIG. 3, since the acoustic lens 21 is usually made of a material having a low attenuation factor,
A multiple number of times of multiple reflected waves are received by the oscillator 22 (hereinafter, the number of times of reflection is indicated by a subscript such as P _{L3 for} triple reflected waves).

The ultrasonic wave received by the ultrasonic oscillator 22 is converted into an electric signal and output, and the distributor 26 outputs the received signal of the oscillator 22 to the two receiving lines 27a and 27b.
Distribute to. The reception signal distributed to the reception line 27a is directly input to the A port of the subtraction circuit 28. On the other hand, the received signal distributed to the receiving line 27b is delayed by the delay circuit 2 based on the delay time set by the delay time setting circuit 31.
A delay is given by 9 and the level is adjusted by the level adjusting circuit 30 based on the amplification factor set by the level setting circuit 32, and is input to the B port of the subtracting circuit 28. The subtraction circuit 28 outputs the difference between the signals input to these ports A and B, and this output signal is the amplifier 3
It is amplified by 3 and output to an image processing circuit or the like in the subsequent stage.

FIG. 2 shows input signals ((a) and (b)) input to the ports A and B of the subtraction circuit 28 and the subtraction circuit 2
8 is a waveform diagram showing an output signal ((c)) output from FIG. In the figure, P _p is an excitation pulse applied to the oscillator 22. In the illustrated example, the double reflected wave P _L2 and the defect echo P _f
And are redundant, and cannot be distinguished as they are. The delay time setting circuit 31 sets the double reflected wave P _L2 in the input signal to the port A and the multiple reflected wave P _L1 in the input signal to the port B to have the same phase, that is, the multiple reflected wave P _{L of the} port B. _L sets the delay time to delay one cycle with respect to the multiple reflection waves P _L port a. This delay time is approximately equal to the propagation time of one round trip of the ultrasonic wave in the acoustic lens 21. On the other hand, in the level setting circuit 32, two multi-reflected waves P _L (for example, multi-reflected wave P _L1 and double-reflected wave P _L2 ) deviated by one cycle are _input to ports A and B.
The amplification factors are set so that they are at the same level when they are input to. This amplification factor corresponds to the attenuation factor given when the ultrasonic wave makes one round trip in the acoustic lens 21.

The method of setting the delay time and the amplification factor is arbitrary, but in the present embodiment, the input signal to the ports A and B of the subtraction circuit 28 and the subtraction circuit 28 by the waveform observing device 34 are used.
The delay time and the amplification factor are set while observing the output signal of (the waveform observed by the waveform observing device 34 is as shown in FIG. 2). It is preferable that the test object at the time of setting the delay time and the amplification factor is a standard test object having the same material as the test object 23 to be flaw-detected and having no defect. On the other hand, since the delay time and the approximate value of the amplification factor can be estimated from the material and size of the acoustic lens 21, the delay time setting circuit 31 and the level setting circuit 32 are set in advance according to the estimated delay time and the amplification factor. Alternatively, the output may be appropriately corrected while observing the output from the amplifier 33.

When the subtraction circuit 28 calculates the difference between the input signals input to the ports A and B of the subtraction circuit 28, that is, the signals shown in FIGS. 2 (a) and 2 (b), the multiple reflected wave P _L is obtained. 1
Since the multiple reflected waves P _L of the same phase are subtracted with a periodic delay and are adjusted to the same level as each other, the components of the multiple reflected waves cancel each other out, and as shown in FIG. Only the excitation pulse P _p , the surface echo P _s and the defect echo P _f are extracted. As a result, as shown in FIG. 2, even when the multiple reflected waves P _L and the defective echo P _f overlap and interfere and are received, only the defective echo P _f can be extracted and measured, and the defect 7 can be accurately measured. It is possible to obtain various information. Moreover, even if the distance between the lens 21 and the subject 23 changes, it is not necessary to change the setting.

Here, in the present embodiment, the reception signal obtained from the single probe 20 is used for two reception lines without using the plurality of probes UP1 and UP2 as in the above-mentioned conventional example. 27a and 27b, and these reception lines 27a and 27a
Since the influence of the multiple reflected waves P _L is removed by performing the predetermined signal processing on the received signal flowing through 27b, it is possible to save the labor of producing a plurality of probes having the same characteristics as in the conventional example, and The entire size including the probe 20 can be reduced.

Second Embodiment FIG. 4 is a block diagram showing an ultrasonic flaw detector which is a second embodiment of the ultrasonic inspection apparatus according to the present invention. In the following description, the same components as those in the above-mentioned first embodiment are designated by the same reference numerals.

The received signal output from the ultrasonic probe 20 is directly input to the A / D converter 41 of the computer 40, converted into a digital signal, and input to the CPU 42. The CPU 42 includes the first to fourth memories 43a to 43
d is connected, and the signal input to the CPU 42 is appropriately stored. The CPU 42 is also connected to a delay setting numeric keypad 44 for setting a delay time described later and a level adjustment numeric keypad 45 for similarly setting a level adjustment. The output from the CPU 42 is the D / A converter 4
6 is displayed on the screen of the CRT 47. The basic configuration (the probe 20, the transmitter 26, etc.) is the same as that of the above-described first embodiment except that the received signal is branched and delayed, and the level is adjusted to one side. And the description is omitted.

Next, the flowcharts of FIGS. 5 and 6,
The operation of the ultrasonic flaw detector according to this embodiment will be described with reference to FIGS. The program shown in the flowchart of FIG. 5 is a program for initial setting and is executed prior to the flaw detection operation of the subject 23. Basically, it may be performed once for the same subject 23.

First, in step S1, the ultrasonic probe 2
The echo from the subject 23 is received by 0. That is, as in the first embodiment, the transmitter 24 generates a pulse for exciting the ultrasonic probe 20 in response to a command from the CPU 42, and the pulse vibrates the ultrasonic wave of the probe 20 via the circulator 25. It is input to the child 22. The oscillator 22 is excited by the pulse to generate an ultrasonic wave, and the ultrasonic wave is generated by the acoustic lens 2.
1 is propagated and irradiated toward the subject 23. Upon irradiation with ultrasonic waves, surface echoes and defect echoes are returned from the subject, multiple reflection echoes are returned from the acoustic lens 21, and these echoes are received by the transducer 22 of the ultrasonic probe 20. The ultrasonic wave received by the ultrasonic transducer 22 is converted into an electric signal and outputted, and after being converted into a digital signal by the A / D converter 41, it is inputted into the CPU 42.

In step S2, the CPU 42 reads the received signal data and stores it in the first memory 43a. In step S3, the CPU 42 causes the first memory 43
The received signal data is read by the CRT 47 by reading the data stored in a and sending it to the D / A converter 46.
Display on top.

In step S4, while the operator observes the data displayed on the CRT 47 (corresponding to FIG. 2A in the first embodiment), the delay setting numeric keypad 44 is used to set one of multiple reflection echoes. Set the delay time for the cycle. Similarly, in step S5, the operator sets the gain for level adjustment using the ten keys 45 for level adjustment while observing the data displayed on the CRT 47. This gain is shifted by one cycle, as in the first embodiment described above.
The two multiple reflection echoes are set to the same level. In step S6, the delay time set in steps S4 and 5 and the level adjustment setting result are stored in the second memory 43b.
Store in.

Next, the program shifts to the program shown in the flowchart of FIG. First, step S11
Then, as in step S1, the ultrasonic probe 20 receives an echo from the subject 23. Step S12
Then, the received signal data of the ultrasonic probe 20 is transferred to the CPU 42.
Read and store it in the third memory 43c.

In step S13, the CPU 42 reads the delay time and the level adjustment setting result stored in the second memory 42b. In step S14, the CPU 42 causes the third
The received signal data stored in the memory 43c is read, and in step S15, the received signal data read in step S14 is delayed by the delay time read in step S13. In step S16, the level of the received signal data to which the predetermined delay has been added in step S15 is adjusted based on the level adjustment setting read in step S13. The received signal data at the time when step S16 ends is shown in FIG. 2B in the first embodiment.
Equivalent to. In step S17, the CPU 42 stores the received signal data that has undergone the predetermined delay and level adjustment in the fourth memory 43d.

In step S18, the CPU 42 causes the third,
The data is read from the fourth memories 43c and 43d, respectively, and the difference between the data in these memories 43c and 43d is calculated. As described above, the data in the fourth memory 43d is delayed from the data in the third memory 43c by the delay time of one cycle of the multiple reflection echo, and the two multiple reflections shifted by one cycle. Since the levels are adjusted so that the echoes have the same level, the components of the multiple reflected waves cancel each other out by the difference calculation, and only the excitation pulse, the surface echo and the defective echo are extracted from the output signal. This difference signal corresponds to that in FIG. 2C in the first embodiment. In step S19, the CPU 42 uses the difference calculation result in step S18 as the D / A converter 4
This calculation result is displayed on the CRT 47 by being sent to the CRT 47. Therefore, according to the present embodiment as well, the above-mentioned first
It is possible to obtain the same effect as that of the embodiment.

In the correspondence between the embodiment described above and the claims, the distributor 26 is a branching means, the delay circuit 29 is a delay means, the level adjusting circuit is a level adjusting means, and the subtracting circuit 28 is a subtractor. The delay time setting circuit 31 constitutes delay setting means, and the level setting circuit 32 constitutes level setting means.

The details of the ultrasonic inspection method and apparatus of the present invention are not limited to the above-described embodiments, and various modifications are possible. As an example, which of the receiving lines 27a and 27b is provided with the delay circuit 29 and the level adjusting circuit 30 is arbitrary, and only one of the lines 27a and 27b is provided.
It may be provided in b. The same result can be obtained by extracting only the multiple reflected waves from the received data, adjusting the level, and then partially subtracting the difference from the received data.

[0033]

As described in detail above, according to the present invention, a received signal obtained from a single ultrasonic probe is not required, unlike the conventional example described above, which uses a plurality of probes. Since the effect of multiple reflected waves is removed by performing a predetermined signal processing on the above, it is possible to save the labor of creating a plurality of probes having the same characteristics as in the conventional example, and moreover, the whole including the probe. Can be miniaturized.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of an ultrasonic flaw detector to which an ultrasonic inspection apparatus according to the present invention is applied.

FIG. 2 is a waveform diagram for explaining an example of the ultrasonic flaw detection method of the first embodiment.

FIG. 3 is a diagram showing a reflected wave received by an ultrasonic probe.

FIG. 4 is a block diagram showing a second embodiment of an ultrasonic flaw detector to which the ultrasonic inspection apparatus according to the present invention is applied.

FIG. 5 is a flow chart for explaining an example of the ultrasonic flaw detection method of the second embodiment.

FIG. 6 is a flowchart similar to FIG.

FIG. 7 is a schematic configuration diagram showing an example of a conventional ultrasonic inspection apparatus.

FIG. 8 is a block diagram showing a specific configuration of the receiver of FIG.

FIG. 9 is a waveform diagram for explaining the operation of the conventional ultrasonic inspection apparatus.

[Explanation of symbols]

 20 ultrasonic probe 21 acoustic lens 22 ultrasonic transducer 26 distributor 27a, 27b reception line 28 subtraction circuit 29 delay circuit 30 level adjusting circuit 31 delay time setting circuit 32 level setting circuit

Claims (5)

[Claims] 1. An ultrasonic inspection method using an ultrasonic probe including an acoustic lens for transmitting and receiving ultrasonic waves to and from a subject, comprising: receiving a pair of reception signals from the ultrasonic probe. The signal is branched into a distribution signal, a delay unit gives a predetermined delay to one of the reception distribution signals, a level adjusting unit adjusts the levels of the pair of reception distribution signals, and a subtracting unit adjusts the level of the pair of reception distribution signals. Seeking the difference,
An ultrasonic inspection method characterized in that a signal that has been multiple-reflected in the acoustic lens is removed from the received signal. 2. An ultrasonic inspection apparatus having an ultrasonic probe for transmitting and receiving ultrasonic waves to and from a subject, comprising an acoustic lens, comprising: a pair of reception distribution signals received from the ultrasonic probe. Distribution means for branching into signals, delay means for giving a predetermined delay to one of the reception distribution signals, level adjusting means for adjusting the level of the pair of reception distribution signals, and difference between the pair of reception distribution signals An ultrasonic inspection apparatus comprising: a subtraction unit that obtains 3. The ultrasonic inspection apparatus according to claim 2, wherein a delay setting unit that variably sets a delay time given by the delay unit, and a level of the reception distribution signal adjusted by the level adjusting unit. An ultrasonic inspection apparatus comprising: a level setting unit that variably sets. 4. An ultrasonic inspection method using an ultrasonic probe, comprising an acoustic lens, for transmitting and receiving ultrasonic waves to and from a subject, wherein a received signal from the ultrasonic probe is stored in a storage means. The received data is stored as a received data in the received data, the delay means gives a predetermined delay to the received data, the level adjusting means adjusts the level of the received data to obtain reference data, and the subtracting means stores the received data and the reference data. An ultrasonic inspection method, wherein a difference is obtained, and a signal that is multiple-reflected in the acoustic lens is removed from the received data. 5. An ultrasonic inspection method using an ultrasonic probe, comprising an acoustic lens, for transmitting and receiving ultrasonic waves to and from an object, the received signal from the ultrasonic probe being stored in a storage means. Stored in the acoustic lens as the received data, and the extracting means extracts from the received data the multiple reflected signal which is multiple reflected in the acoustic lens and the interference signal in which the multiple reflected signal interferes with the signal to be inspected, and the level adjusting means. Adjusting the levels of the multiple reflection signal and the interference signal by means of calculating the difference between the multiple reflection signal and the interference signal by subtracting means, and removing the multiple reflection signal from the received data. Sonography method.