JPH0843361A - Ultrasonic measuring device - Google Patents

Abstract

(57) [Abstract] [Purpose] It is an object of the present invention to provide an ultrasonic measuring device capable of easily extracting a defect echo from an interference wave between a sample surface echo and a defect echo. [Structure] A signal-isolated transmission circuit is provided so that the reference of the signal level on the secondary side corresponds to the level of the surface echo, and the level of the surface echo is regarded as an offset for correction. To get the received signal,
The surface echo level is lowered to near 0V and detected. Therefore, the level of the reflected echo can be detected with this level as a reference. Moreover, since the signal level of the surface echo is eliminated and reduced, the detected reflected echo can be greatly amplified, and the defect signal can be separated more accurately.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic measuring device, and more particularly, to an ultrasonic inspection imaging device for transmitting a burst wave (continuous wave) ultrasonic wave to collect an image immediately below a surface, The present invention relates to an ultrasonic measuring device capable of easily separating and detecting a defect echo.

[0002]

2. Description of the Related Art An ultrasonic image inspection apparatus, which is one of ultrasonic measurement apparatuses, can display the inside of a subject as an image of a B scope image or a C scope image. In order to collect clearer images, this type of imaging device inputs various measurement conditions such as the acoustic characteristics of the probe, the medium, the speed of sound inside the subject at that time, and the like. Set the focus of the probe to the desired depth position within. For that purpose, focus work, gate position, and gate width are set.

A high-resolution ultrasonic image exploration apparatus is more expensive as its resolution is higher, and its measurement operation requires skill. Apart from this, there is an ultrasonic image inspection apparatus that improves resolution without using high frequencies. This utilizes the interference wave between the sample surface echo and the defect echo (including the sample interface echo, the same applies below),
In this case, the ultrasonic waves used for measurement are not pulse waves,
It becomes a burst wave.

[0004]

In the inspection of IC or the like, the boundary surface (defect) near the surface is inspected. However, when an image such as a crack directly below the surface of a member is obtained, Since the echo level is high and the position of the crack is very close to the surface, the reflection echo of the crack is superimposed on the surface echo, which makes it very difficult to detect the level of the reflection echo from the interference wave. In addition, the extraction of the interference wave between the sample surface echo and the defect echo by the burst wave is performed by setting the gate position appropriately.However, when the burst wave is used and the pulse wave is different, it is a continuous wave. It is difficult to fix the wave state of the wave, and it is difficult to detect an appropriate peak because the wave state changes depending on the frequency, and it is difficult to properly set the gate position for the defective echo portion. An object of the present invention is to solve such a problem of the conventional technique, and to provide an ultrasonic measurement device capable of easily extracting a defect echo from an interference wave between a sample surface echo and a defect echo. Especially.

[0005]

The features of the ultrasonic measuring apparatus of the present invention for achieving such an object are that an ultrasonic probe and a burst signal for driving the ultrasonic probe are generated. The burst signal generation circuit, the primary side and the secondary side are insulated, and the signal insulation transmission circuit that extracts the echo reception signal from the secondary side by adding the echo reception signal from the ultrasonic probe to the primary side and this signal insulation A voltage generation circuit that sets the reference level of the secondary side signal of the transmission circuit according to the control signal, and a peak detection circuit that detects the peak value of the detection signal of the secondary side signal of the signal isolation transmission circuit. , The peak value of the interference wave between the surface echo or the surface echo and the defect echo directly under the surface obtained by this peak detection circuit is obtained, and a voltage value corresponding to the level of the surface echo is obtained and offset by this voltage amount. In which a control circuit for sending a control signal to generate a reference level to the voltage generating circuit.

[0006]

As described above, by providing the signal isolation transmission circuit and making the reference of the signal level on the secondary side correspond to the level of the surface echo, the level of the surface echo is regarded as an offset and corrected. As a result, for example, when the echo reception signal on the positive side is obtained, the surface echo level is lowered to near 0 V for detection, and the level of the reflected echo can be detected with this level as a reference. Moreover, since the signal level of the surface echo is eliminated and reduced, the detected reflected echo can be greatly amplified, and the defect signal can be separated more accurately. Further, the gate position can be set by capturing the interference wave between the surface echo and the defect echo,
The setting for extracting only the defective echo portion from the interference wave is not required, and the setting can be easily made because it is relatively rough.

[0007]

1 is a block diagram of an ultrasonic image inspection apparatus according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram of signal waveforms of respective parts thereof. In FIG. 1, 20 is an ultrasonic image inspection apparatus, and 1 is its scanning mechanism having an XYZ moving mechanism. The focus type probe 3 is attached to the scanning mechanism 1 to perform a main scan of the subject 15 in the Y direction,
The sub-scan is performed in the X direction.

The ultrasonic image inspection apparatus 20 obtains a measurement value by which an A scope image is obtained at each measurement point by this XY scanning, and based on this, display data of the B scope image and display data of the C scope image are obtained. Generate B scope image and C
Display the image of the scope image. The subject 15 in this embodiment is, for example, the bottom of a container in which a crack or the like occurs just below the surface.

The scanning mechanism 1 is controlled by the scan control device 2, and the scan control device 2 is controlled by the image processing / control device 11 via the interface 8. The probe 3 is connected to the ultrasonic flaw detector 4. The ultrasonic flaw detector 4 includes a reception circuit 40, a gate circuit 41, a high-frequency pulse transformer (pulse transformer) 42 that receives an echo reception signal from the probe 3, and an offset voltage generation circuit 4.
3, diode 44, high frequency amplifier 45, detection circuit 4
6, and a burst wave transmitter 47.

The receiving circuit 40 has a high frequency amplifying circuit inside, and receives an echo received signal from the probe 3 and amplifies the received signal with an amplification factor according to a control signal from the image processing / control device 11. T wave (transmitted signal on the receiving side)
And surface echo (S echo), defect echo (F echo),
Then, the RF signal composed of the bottom echo (B echo) (see FIG.
(see (a)) is generated and sent to the gate circuit 41. The gate circuit 41 applies a gate (see FIG. 2 (b)) to a predetermined position with respect to the echo reception signal amplified according to the control signal from the image processing / control device 11 to generate a surface echo as a necessary echo portion. The pulse transformer 42 is extracted by extracting the interference wave part (see FIG. 2 (c)) between the defect echo under the surface and the defect echo.
Add to The gate position and its width are determined by a setting signal received from the image processing / control device 11 via the interface 8. The pulse transformer 42 receives the signal of FIG. 2 (c) on the primary winding and applies the output from the secondary winding to the high frequency amplifier 45. The terminal 42a, which is not the input side of the primary winding, is grounded.

The offset voltage generating circuit 43 comprises a programmable constant current source circuit 43a having a switch circuit internally connected to the ground potential and a resistor R.
The switch circuit is turned on by a signal from the control device 11.
Then, the terminal of the resistor R on the output side is set to "0" V, or a constant negative voltage is generated when the switch circuit is OFF. Then, this voltage is applied as an offset voltage to the terminal 42b which is not the output side of the secondary winding of the pulse transformer 42. The high frequency amplifier 45 amplifies the rectified echo reception signal (see FIG. 2 (d)) and sends it to a detection circuit 46 for envelope detection. The diode 44 is inserted in the reverse direction between the input of the high frequency amplifier 45 and the ground,
This is a rectifier circuit that cuts the negative-side signal component of the echo reception signal, and here only the positive-side signal is the high-frequency amplifier 45.
(See Fig. 2 (d)).

The image processing / control device 11 generates a control signal of a repetitive pulse PRF according to the measurement cycle and, in addition to the burst wave oscillator 47, drives the probe 3 by the burst wave. The probe 3 converts an echo obtained from the subject 15 into an electric signal with respect to the transmission wave T (see FIG. 2 (a)) of the burst wave generated in response thereto, and the converted electric signal from the probe 3 is transmitted. The reception circuit 40 receives the echo reception signal. The received signal passes through the gate circuit 41 and the pulse transformer 42, is amplified by the high frequency amplifier circuit 45 (see FIG. 2 (e)), and is detected by the detection circuit 46 (see FIG. 2 (f)). Then, it is sent to the peak detection circuit 5 and the time measurement circuit 6. The peak detection circuit 5 has a peak hold circuit and a sample hold circuit, detects the peak value of the input signal, and outputs this to the A / D conversion circuit 7.

The time measuring circuit 6 is a circuit for measuring the elapsed time after the surface echo is detected. The time measuring circuit 6 obtains the elapsed time from the surface echo or from the count start signal to the data measurement for each measurement data, and this is measured via the interface 8. And sends it to the image processing / control device 11. The A / D conversion circuit 7 converts the analog signal of the peak value obtained according to the control signal from the image processing / control device 11 into a digital value in 8-bit 256 steps, for example. This digital value is converted into a microprocessor (MP of the image processing / control device 11
U) 9 is sent to the bus 14 as input data so that it can be processed. The image processing / control device 11 includes, in addition to the microprocessor 9, an operation panel (not shown), a memory 10 storing various programs and data, an image memory 12,
It has a display 13 and the like, which are connected via a bus 14. The memory 10 is provided with an offset voltage measurement program 10a, a plane scanning program 10b, a focusing program 10c, a parameter storage area 10d, and the like.

In the above configuration, the ultrasonic image inspection apparatus 2
0 indicates that the probe 3
Scans the subject 15 on the XY plane by reciprocal scanning in the Y direction, which is one line scan in the Y direction and is then pitch-fed in the X direction. In this scanning, the peak value is detected by the peak detection circuit 5 for each measurement point assigned at a predetermined pitch, and the MPU 9 takes in the peak value in the form of a digital value. The MPU 9 sequentially stores the peak value data in the memory 1 corresponding to each measurement point.
It will be memorized at 0.

In this embodiment, the offset voltage measuring program 10a is first executed by the MPU 9 at the start of ultrasonic measurement. As a result, the offset voltage measurement program 10a turns on the internal switch circuit to ground the output, and generates a voltage of "0" V at the terminal 42b that is not the output side of the secondary winding of the pulse transformer 42 to ground it. Let Then, the surface echo S is used as the gate range.
And a defect echo F are included in the range (see FIG. 2).
(See (b)), the peak value p obtained from the peak detection circuit 5
(See FIG. 2 (f)).
Is calculated and a control signal for setting the terminal voltage of the resistor R to Ps is added to the offset voltage generating circuit 43. Note that Ps is
It corresponds to the level of the surface echo, and α in this case can be obtained as an experimental value that makes Ps correspond to the level of the surface echo. Instead of α, the gate width may be narrowed to extract only the surface echo portion and the peak value may be sampled as the reference voltage value Ps.

As a result, as shown in FIG. 2 (d),
Grounding side terminal voltage 42 of the secondary winding of the pulse transformer 42
b becomes -Ps. As a result, the ground level shifts to near the surface echo level as shown by the dotted line in (d) and (e) of FIG. At this time, the reference on the primary side of the pulse transformer 42 is "0" V. Therefore, the peak value detected by the peak detection circuit 5 is as shown in FIG.
The peak hold output to the conversion circuit 7 is as shown in FIG. As a result, the surface echo level becomes close to "0" V, and the surface echo level can be suppressed low. Therefore, even if the amplification degree of the high frequency amplifier 45 is increased, this amplifier will not be saturated and the amplification factor can be made large, so that only the defect echo can be detected more clearly than in the conventional case.

Although the pulse transformer is used in the embodiment as described above, a signal-insulated transmission circuit such as a photocoupler capable of separating the primary side and the secondary side may be used.
Further, in the embodiment, the high frequency amplifier circuit is provided after the pulse transformer, but since the high frequency amplifier circuit is provided in the receiving circuit, the high frequency amplifier circuit 45 can be omitted. The echo reception signal amplified by the high frequency amplifier circuit 45 is
Although the negative side is cut to obtain the positive side signal component, the positive side may be cut to obtain the negative side signal component. In this case, the reference level on the secondary side of the pulse transformer is shifted to the positive side. Further, in the embodiment, only the ultrasonic image inspection device is given as an example, but since the present invention is mainly focused on the offset adjustment corresponding to the level of the surface echo before the peak detection, various ultrasonic measurement devices are used. Is applicable to.

[0018]

As can be understood from the above description, in the present invention, the signal isolation transmission circuit is provided so that the reference of the signal level on the secondary side corresponds to the level of the surface echo, and the level of the surface echo is changed. Since the correction is performed by regarding it as an offset, for example, when an echo reception signal on the positive side is obtained, the surface echo level is lowered to near 0 V and detected. Therefore, the level of the reflected echo can be detected with this level as a reference. Moreover, since the signal level of the surface echo is eliminated and reduced, the detected reflected echo can be greatly amplified, and the defect signal can be separated more accurately. In addition, the gate position can be set simply by capturing the interference wave between the surface echo and the defect echo, so the setting that extracts only the defect echo part from the interference wave is not required, and it can be relatively rough and easy to set. Get out. As a result, even if the level of the surface echo is high, the defect echo can be detected, and the defect immediately below the surface can be clearly detected. When measuring a defect directly under the surface, the measurement can be easily performed and the operability of the device is improved.

[Brief description of drawings]

FIG. 1 is a block diagram of an ultrasonic image inspection apparatus according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of signal waveforms of respective parts of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Scanning mechanism, 2 ... Scan control device, 3 ... Probe
4 ... Ultrasonic flaw detector, 5 ... Peak detecting circuit, 5a ... Gate position adjusting circuit. 6 ... Time measuring circuit, 7 ... A / D conversion circuit, 8 ... Interface, 9 ... Microprocessor (M
PU), 10 ... Memory, 10a ... Offset voltage measurement program, 10b ... Planar scanning program, 10c ... Focusing program, 10d ... Parameter storage area, 11
... image processing device, 12 ... image memory, 13 ... display, 14 ... bus, 15 ... touch screen, 16 ... touch screen interface, 15 ... object, 20 ... ultrasonic measurement device, 40 ... burst wave transmitter, 41 ... Receiver circuit, 42 ... High frequency pulse transformer (pulse transformer),
43 ... Offset voltage generating circuit, 44 ... Diode, 4
5 ... High frequency amplifier, 46 ... Detection circuit.

Claims (2)

[Claims] 1. An ultrasonic probe, and a burst signal generation circuit for generating a burst signal for driving the ultrasonic probe,
A signal insulation transmission circuit, in which a primary side and a secondary side are insulated, and an echo reception signal from the ultrasonic probe is applied to the primary side to take out the echo reception signal from the secondary side, and this signal insulation transmission circuit A voltage generating circuit that sets the reference level of the secondary side signal according to the control signal, and a peak detection circuit that detects the peak value of the detection signal of the secondary side signal of the signal isolation transmission circuit, A voltage value corresponding to the level of the surface echo is obtained from the peak value of the surface echo obtained by this peak detection circuit or the interference wave between the surface echo and the defect echo immediately below the surface, and the voltage value is canceled by the voltage value. An ultrasonic measurement device, comprising: a control circuit that sends the control signal that generates a reference level to the voltage generation circuit. 2. A high-frequency amplification circuit and a detection circuit are further provided, and the front signal insulation transmission circuit is a high-frequency pulse transformer. The signal on the secondary side of the high-frequency pulse transformer is amplified by the high-frequency amplification circuit to detect the detection circuit. The signal on the secondary side is rectified by a diode and the signal on the positive side is added to the high-frequency amplifier circuit, and the cancellation is performed with the reference level being negative. The ultrasonic measurement device according to claim 1, which is for shifting to the side.