JPH03221862A - Ultrasonic inspecting device - Google Patents

Abstract

PURPOSE:To make the focusing position of an ultrasonic wave coincide with a coordinate and to accurately detect the defective position of a subject to be checked by detecting and correcting deviation between the reference position of a scanning means and the focusing position of the ultrasonic wave based on the result of scanning. CONSTITUTION:The scanning means 3 scans a line segment A-A' and a line segment B-B' parallel with a Y-axis. A probe 2 transmits an ultrasonic pulse to the reference subject S, and the reflected ultrasonic wave is received by the probe 2 again and transmitted to a gate circuit 5 through a pulser receiver 4. As to the output of a surface distance counter 6, a distance to the bottom of the groove Sd of the reference subject S is compared with a level equivalent to the middle of other distance to the surface in a control processing circuit 9 and the coordinate of a position where the scanning means 3 is located among four points where length relation between them is reversed is stored. The circuit 9 separately averages the X and Y components of the coordinate, measures and stores a difference from the coordinate of the center line of the center line of the groove Sd of the subject S which is previously inputted and finishes the preparation of correction. At the time of inspection, the stored difference is subtracted from the coordinate of the means 3 to obtain an output value.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an ultrasonic inspection apparatus that scans a subject with a focused ultrasonic probe and performs defect inspection using a pulse echo method.

[Conventional technology] Ultrasonic pulses are transmitted toward the object while scanning the object using a focused ultrasonic probe, and the depth and distribution of defects within the object are displayed from the reflected signals. Ultrasonic testing devices that do this are widely known.

Conventionally, when inspecting a regular-shaped object with this type of device, the object is fixed at a fixed position on a sample stage, and the scanning range is adjusted to the previously known position and size of the object. How to set up is done. At this time, the ultrasound probe is fixed so that the position of the ultrasound probe and the coordinates of the scanning means match.

[Problem to be solved by the invention] However, in general, the center of the ultrasound probe and the focal position of the ultrasound waves are often misaligned, and the focal position of the ultrasound waves and the coordinates of the scanning means are misaligned. This results in a deviation between the scanning range and the range actually measured by ultrasonic waves. For this reason, positional deviation occurs when specifying the position of a defect within the object to be inspected from the measurement results or when processing measurement data for a fixed range within the object to be inspected.

This drawback becomes a major problem when the measurement resolution is high or when the object to be measured is small. Furthermore, when setting the scanning range, it is necessary to take into account the deviation and set a measurement range that is correspondingly larger, which results in wasted scanning time and data memory.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and provide an ultrasonic inspection apparatus in which the focal position of ultrasonic waves and coordinates coincide.

[Means for Solving the Problems] In order to achieve the above-mentioned object, in the ultrasonic inspection apparatus according to the present invention, ultrasonic pulses are directed toward the subject from a focused ultrasound probe that scans the subject. In an apparatus for inspecting the inside of an object using the reflected signal, a scanning means scans a reference object, and the amount of deviation between the reference position of the scanning means and the focal position of the ultrasonic wave is calculated based on the scanning result. The present invention is characterized in that it comprises a detection means for detecting the amount of deviation, and a correction means for correcting the position of the scanning means based on the amount of deviation detected by the detection means.

[Operation] The ultrasonic inspection apparatus having the above-mentioned configuration detects the amount of deviation in the coordinates of the scanning means from the result of scanning a reference object placed in a fixed position and having a known shape, and performs correction based on this,
Match the coordinates and the ultrasound focus position.

[Example] The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows a configuration diagram of the apparatus, in which a reference subject S serving as a measurement standard is fixed at a fixed position in a water tank 1 by the ultrasonic water immersion method. The ultrasonic probe 2 that transmits and receives ultrasonic waves to and from the reference object S is attached to the scanning means 2 with its tip immersed in water, so that it can be scanned in a horizontal plane by the scanning means 3. It has become. Further, the probe 2 is connected to a balsa receiver 4 that applies a voltage to generate ultrasonic waves and amplifies a received signal. The output of the received signal of the balsa receiver 4 is separated into signal elements via a gate circuit 5, and is then separated into a surface distance counter 6, a signal strength detector 7,
Each of the defect depth counters is connected to a defect depth counter 8, and each output is further connected to a control processing circuit 9. The control processing circuit 9 sends control signals to the scanning means 3 to control scanning, sends output signals to the image output means 10 and the printing means 1], and functions according to input commands from the instruction manual means 12. .

In the above configuration, the control processing circuit 9 controls the scanning means 3 in accordance with the instruction to start the correction preparation stage from the command output means 12.
As shown in FIG. Scan the parallel line segment BB'.

At the same time, the balsa receiver 4 sends high voltage pulses to the probe 2 at regular intervals, and the probe 2 sends ultrasound pulses toward the reference object S. The ultrasonic waves reflected from the surface of the reference object S are received by the probe 2 again and sent to the balsa receiver 4.
The signal is amplified and sent to the gate circuit 5. At this time, the gate circuit 5 and the surface distance counter 6 are electrically synchronized with the balsa receiver 4, and the time elapses from transmitting the ultrasonic wave until receiving the reflected signal from the surface of the reference object S. Count. The output of the surface distance counter 6 is compared in the control processing circuit 9 with levels t and o corresponding to the intermediate distance between the distance to the bottom of the groove Sd of the reference object S and the distance to other surfaces. The coordinates at which the scanning means 3 is located at four points whose magnitude relationship is reversed are stored. The control processing circuit 9 averages these coordinates separately for the X component and the Y component, calculates and stores the difference with the coordinates of the center cotton of the groove Sd of the reference object S that has been input in advance, and completes the correction preparation stage. do. At the time of inspection, this stored difference is subtracted from the coordinates of the scanning means 3 to obtain an output value.

FIG. 3 shows an output figure obtained by the surface distance counter 6 when scanning along the line A-A' in FIG. Reference object S from the tip of probe 2
Since the distance to the surface and the output of the surface distance counter 6 are proportional, the edge positions e and e' of the groove Sd of the reference object S can be detected by comparing the output of the surface distance counter 6 with the level to. By finding the midpoint X°, the center position of the groove Sd can be detected. The difference ΔX between the detected center position X′ of the groove Sd and the actual position X of the groove Sd is the amount of deviation in the X-axis direction between the focal position of the ultrasonic wave and the coordinates of the scanning means 3. Y
In the axial direction, the deviation amount Δy is similarly detected by scanning the line segment BB'.

In actual scanning, the set range can be accurately measured by scanning a range shifted by the detected deviation amounts ΔX and Δy with respect to the set scan range. Furthermore, since the output is corrected, there is no positional deviation.

FIGS. 4 and 5 show a second embodiment regarding detection of the amount of deviation. FIG. 4 shows the shape of the reference object S' of the second embodiment, in which a thin groove S' is cut in the shape of a cross on a flat plate. The detector 7 detects the intensity of the reflected signal from the surface of the reference object S. FIG. 5 shows the signal when scanning a line segment C-C° parallel to the X axis on the reference object S. The output figure of the intensity detector 7 is shown, and ■ is the output of the signal intensity detector 7.Groove S
Since the reflected signal is scattered above d', the signal strength becomes weaker, so the output of the signal strength detector 7 becomes a level Io.
The position of the groove Sd' can be detected by finding the center of the intersection f, f' between the outputs I and Io, and the deviation amount ΔX can be detected from the difference between the detected position and the actual position. Similarly, the displacement amount Δy in the Y direction can be detected by scanning the line segment DD′ parallel to the Y axis.

FIGS. 6 and 7 show a third embodiment regarding detection of the amount of deviation, and the reference object S" is a cylinder as shown in FIG. 6. FIG. 7 shows the range of E in FIG. was scanned two-dimensionally, and from the output of the surface distance counter 6 at that time, the edge of the reference object S° was detected in the same manner as in the first embodiment, and the position was detected by finding the center. The results are shown. From the difference between the position detected in this way and the actual position of the reference object S°, the amount of deviation in the X and Y directions ΔX, △
y can be detected.

[Effects of the Invention] As explained above, the ultrasonic inspection apparatus according to the present invention can accurately align the coordinates at the time of input and output with the focal position of ultrasonic waves using a reference object, thereby making it possible to The scanning range can be set without waste, and the position of the defect on the object can be accurately determined.

[Brief explanation of drawings]

The drawings show an embodiment of the ultrasonic testing apparatus according to the present invention, and FIG. 1 is a configuration diagram, FIG. 2 is a perspective view of a reference object of the first embodiment, FIG. 3 is a time chart diagram, and FIG. The figure is a perspective view of the second embodiment, Figure 5 is a time chart diagram, and Figure 6 is a diagram of the third embodiment.
FIG. 7 is a perspective view of the reference object of the embodiment, and FIG. 7 is a time chart. 1 is a water tank, 2 is an ultrasonic probe, 3 is a scanning means, 4 is a pulser receiver, 5 is a gate circuit, 6 is a surface distance counter, 7 is a signal strength detector, 8 is a defect depth counter, 9 is a control processing circuit, 10 is an image output means, 11 is a printing means, 1
2 is command manual means, S, S. So. is the reference subject.

Claims (1)

[Claims] 1. In a device that scans the object, a focused ultrasound probe emits ultrasound pulses toward the object, and uses the reflected signals to inspect the inside of the object, scanning over the reference object. a scanning means; a detection means for detecting the amount of deviation between the reference position of the scanning means and the focal position of the ultrasonic wave from the scanning result;
An ultrasonic inspection apparatus comprising: a correction means for correcting the position of the scanning means based on the amount of deviation detected by the detection means.