JP3637146B2 - Method and apparatus for determining wounds to be inspected - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for inspecting an object to be inspected, which is applied to a rail flaw determination device or the like in an ultrasonic rail flaw detection vehicle and determines a flaw on a railroad rail.
[0002]
[Prior art]
FIG. 2 is a perspective view showing a measurement state when a rail (inspection material) such as a conventional railway is flaw-detected with ultrasonic waves, and FIG. 3 is a block diagram showing a functional configuration of the ultrasonic flaw detection apparatus 2. 2 and 3, in this example, the ultrasonic probe 4 provided at the tip of the cable 3 connected to the ultrasonic flaw detector 2 is moved on the rail (inspection material) 1 to be flaw detected. The rail 1 is inspected.
[0003]
In the ultrasonic flaw detector 2 shown in FIG. 3, the ultrasonic probe 4 moves on the rail 1 in contact. At this time, a transmission signal output from the transmission unit 2 a at a constant cycle is input to the ultrasonic probe 4, and an ultrasonic pulse from an internal transducer (not shown) is radiated to the rail 1. This ultrasonic pulse is reflected by a flaw on the rail 1, and this reflected wave is received by the transducer in the ultrasonic probe 4.
[0004]
This received signal is input to the receiving unit 2b, where it is amplified and input to the signal processing unit 2c. In the signal processing unit 2c, the gate circuit provided here selects only a predetermined beam path range as a detection range, further converts an analog signal into a digital signal, compares the received signal bell with a determination level, and reflects echoes. Is detected. Based on the detected reflected echo data and movement amount data from a travel distance sensor (not shown), the position of the scratch on the rail 1 and its severity are determined, and the result data is displayed on a display unit 2d such as a cathode ray tube (CRT). Is displayed on the screen. Further, it is stored and stored in a memory or the like of the recording unit 2e, and further printed on a recording sheet and output as necessary.
[0005]
In this case, the severity is determined based on the range in which reflected echoes are continuously detected when the ultrasonic probe 4 moves on the rail 1 (hereinafter referred to as a defect indication length). From the idea of representing, it is determined that the greater the defect indication length, the greater the severity.
[0006]
[Problems to be solved by the invention]
However, the determination of the seriousness of the conventional example has the following drawbacks, and this improvement is a problem.
(1) Even when the reflected echo is continuously detected when the ultrasonic probe 4 moves, the number of scratches is not limited to one. For example, as shown in FIG. 4, when two flaws a and b exist, reflected echoes are continuously detected, and as a result, a very large defect indication length is detected.
(2) The defect indication length does not match the actual scratch size depending on the scratch angle. For example, when the scratch is relatively parallel to the moving direction of the ultrasonic probe 4 as shown in FIG. 5A, the defect indication length matches the actual scratch size. When the flaw is inclined with respect to the moving direction of the ultrasonic probe 4 as shown in FIG. 5B, the defect indication length and the actual flaw size do not match.
(3) Since the actual ultrasonic pulse incident on the rail 1 has a wider beam width in the radiation direction, the defect indication length becomes longer than the actual flaw size as shown in FIG. In this case, the extent of the damage at a position farther from the incident position of the ultrasonic pulse becomes larger.
(4) The size of the flaw is reflected in the received signal level of the reflected echo. In other words, since the ultrasonic pulse has a wide beam width, for example, as shown in FIG. 7A, when the scratch is larger than the beam width, the total energy of the ultrasonic pulse is reflected. As shown in FIG. 7B, when the scratch is smaller than the beam width, a part of the energy of the ultrasonic pulse is reflected. That is, the received signal level is higher in the example shown in FIG. 7A than in the example shown in FIG. By the way, information relating to such detection has not been conventionally used, and does not contribute to accurate flaw determination.
(5) The seriousness of the flaw has not only its size, but also an evaluation factor such as how far the flaw has reached from the surface of the rail 1, but this consideration has conventionally been made. In this case, it is difficult to accurately determine the scratches.
[0007]
The present invention solves such a drawback in the conventional technique, and provides an inspection object flaw determination method and apparatus capable of determining the seriousness of flaws in an inspection material such as a railroad rail with high reliability.
[0008]
[Means for Solving the Problems]
In order to achieve the above-described object, the method for determining a wound of an object to be inspected according to the present invention provides a method for determining a wound of a reflected echo from a reflected echo obtained by radiating an ultrasonic pulse to the object to be inspected. A connected area on the B scope image is extracted, and the size, end point position, and representative value of the received signal level of the reflection echo constituting the connected area are extracted as the feature amount of the extracted connected area. Then, based on the feature amount, the severity of the scratch that is the reflection source of the reflection echo constituting the connection region is determined.
[0009]
The inspected object wound determination apparatus of the present invention determines an object to be inspected from a reflected echo obtained by radiating an ultrasonic pulse to the inspected object. A reflection echo is detected from the reception signal of the reflection of the ultrasonic pulse radiated to the body, and the connection region extraction unit extracts a connection region on the B scope image of the reflection echo detected by the reflection echo detection unit. Further, the feature value extraction unit extracts the representative value of the size of the B-scope image, the end point position, and the reception signal level of the reflection echo constituting the connection region as the feature amount of the connection region extracted by the connection region extraction unit. Based on the feature amount extracted by the feature amount extraction unit, the determination unit determines the severity of the scratch that is the reflection source of the reflection echo constituting the connected region.
[0010]
Furthermore, in the inspection object wound determination method and apparatus of the present invention, the representative value of the reception signal level of the reflection echo constituting the connection area is set to the maximum value of the reception signal level of the reflection echo constituting the connection area.
Further, in the inspection object wound determination method and apparatus of the present invention, correction is performed by subtracting the beam width of the ultrasonic pulse from the size of the connected region on the B-scope image.
[0011]
Furthermore, in the inspection object wound determination method and apparatus according to the present invention, a representative value of the beam path of the reflected echo constituting the connected area is further obtained as the extracted feature value of the connected area, and the reflected echo constituting the connected area is determined. The representative value of the received signal level is corrected so that the representative value of the received signal level becomes smaller as the representative value of the beam path of the reflected echo constituting the connection region is smaller.
[0012]
In the method and apparatus for inspecting an object to be inspected according to the present invention, the representative value of the beam path of the reflected echo constituting the connection area is set as the beam path of the reflection echo located at the center of gravity of the connection area.
Further, in the inspection object wound determination method and apparatus of the present invention, the difference between the representative value of the beam path of the reflected echo constituting the connected area and the representative value of the reception signal level of the reflected echo constituting the connected area is minimized. The beam path of the reflected echo at the reception signal level is used. Further, in the inspection object damage determination method and apparatus of the present invention, the inspection object damage determination method and apparatus are applied to a rail damage determination apparatus in an ultrasonic rail flaw detection vehicle while the inspection object is a rail. is there.
[0013]
In such an inspection object wound determination method and apparatus of the present invention, since determination is performed for each connected region on the B-scope image of the reflected echo, the severity of each wound is determined with high reliability.
In addition, since the determination is made using the size on the B scope image instead of the conventional defect instruction length, the actual size of the scratch can be evaluated regardless of the angle of the scratch. The severity of the wound is judged with high reliability.
[0014]
Furthermore, in addition to the size of the flaw on the B scope image, the received signal level is also used to estimate the size of the flaw, and the depth of the flaw from the surface by focusing on the end point position. Therefore, the severity of the wound is determined with high reliability.
Further, the beam width is corrected for the size of the scratch on the B scope image, and the correction according to the beam path considering the spread and attenuation of the beam width is performed for the received signal level. The size of the wound is estimated more accurately.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Next, an embodiment of the method and apparatus for determining a wound to be inspected according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a block diagram showing a configuration of an embodiment of an inspection object wound determination method and apparatus according to the present invention. In FIG. 1, this inspected object wound determination apparatus has an ultrasonic probe 11 that radiates an ultrasonic pulse into the rail 10 while moving on the rail 10 to be inspected and receives a reflected wave. In addition, an ultrasonic transmission / reception unit 12 that transmits transmission signals to the ultrasonic probe 11 at regular intervals during the movement and amplifies and outputs reception signals received by the transducers in the ultrasonic probe 11. have.
[0016]
Furthermore, in this inspected object damage determination apparatus, only the range of a predetermined beam path from the reception signal output from the ultrasonic transmission / reception unit 12 is set as a detection range, and the reflection echo detection unit 13 that converts the detection range into a digital signal and outputs the digital signal. Is provided. The reflected echo detector 13 compares the received signal level with a predetermined determination level, detects a portion of the received signal level equal to or higher than the determined level as a reflected echo, and detects the detected reflected echo, received signal level, and beam path length. And movement distance data indicating the movement amount of the ultrasonic probe 11 is output.
[0017]
The reflection echo detection unit 13 further includes a connection region extraction unit 14 that extracts a connection region of the reflection echo on the B scope image. The reflection echo B scope extracted by the connection region extraction unit 14 is also included. As a feature value of the connected region on the image, a feature value extracting unit 15 is provided that extracts a representative value of the size of the B scope image, the position of the end point, and the reception signal level of the reflected echo constituting the connected region. .
[0018]
In addition, the determination unit 16 that determines the severity of the flaw from the feature amount of the connected area on the B-scope image of the reflected echo extracted by the feature amount extraction unit 15, the position of the determined flaw, and the seriousness of the flaw Display unit 17 composed of a cathode ray tube (CRT) or the like that displays the determination result of the sex on the screen, and the determination result of the determined position and severity of the scratch on the hard disk (HDD) and the printed hardware A recording unit 18 for outputting a copy (recording paper) is provided. Furthermore, it has the movement distance sensor 19 which outputs the movement distance data when the ultrasonic probe 11 moves on the rail 10. The reflection echo detection unit 13, the connected region extraction unit 14, the feature amount extraction unit 15, and the determination unit 16 are configured by a gate circuit, an A / D converter, a counter, a CPU, a memory, an I / O circuit, a device controller, and the like. I can do it.
[0019]
Next, the operation in the configuration of this embodiment will be described.
In FIG. 1, the ultrasonic probe 11 moves while contacting on the rail 10 to be inspected, and this moving distance is detected by a moving distance sensor 19. At this time, the ultrasonic transmission / reception unit 12 outputs transmission signals to the ultrasonic probe 11 at regular intervals during movement based on the movement distance data from the movement distance sensor 19, and vibrations in the ultrasonic probe 11. An ultrasonic pulse is emitted from the child to the rail 10. The ultrasonic pulse is reflected by a flaw on the rail 10 or the like, and the reflected echo is received by the transducer in the ultrasonic probe 11.
[0020]
The received signal is amplified by the ultrasonic transmission / reception unit 12 and output to the reflection echo detection unit 13. The reflection echo detection unit 13 selects a range of a predetermined beam path as a detection range for the reception signal from the ultrasonic transmission / reception unit 12 through a gate circuit (not shown), and converts the analog reception signal into a digital signal. Further, the reflection echo detector 13 compares the received signal level with a predetermined determination level, and detects a portion equal to or higher than the determination level of the reception signal level as a reflection echo. The detected reception echo signal level and beam path, and the movement distance data of the ultrasonic probe 11 obtained by the movement distance sensor 19 are output to the connected region extraction unit 14.
[0021]
Here, the beam path is equivalent to the propagation time from when an ultrasonic pulse is radiated from the ultrasonic probe 11 to the rail 10 until it is reflected by a flaw and received, and this time is counted by a counter or the like. By seeking.
The connected region extracting unit 14 extracts a connected region on the B scope image of the reflected echo detected by the reflected echo detecting unit 13. The B-scope image has a constant pixel value at a position where the reflected echo exists, with the moving distance of the ultrasonic probe 11, that is, the incident position of the ultrasonic pulse and the beam path (propagation time) as the vertical and horizontal axes. , “1”, or a value corresponding to the received signal level of the reflected echo, and the pixel value at a position where no reflected echo exists is, for example, “0”.
[0022]
A connected region on the B-scope image, that is, a set of reflection echo pixels having a connection relationship with each other on the B-scope image is extracted as one connected region. This can be done, for example, using an image processing technique called labeling. This labeling is described in, for example, “Introduction to Computer Image Processing” (Tamura Supervised Research Institute Publishing, 1985), and performs a process of assigning a label (number) to each connected area. As another method, it is also possible to use the method described in “Method and apparatus for extracting connected region of B-scope image” proposed by the applicant of the present application in Japanese Patent Application No. 8-075501.
[0023]
Hereinafter, the connected region extraction processing based on the latter method will be briefly described.
First, every time a reflected echo is detected by the reflected echo detector 13, attention is paid to the position on the B scope image defined by the incident position of the ultrasonic pulse and the beam path, and this position is already used. The position of the reflected echo assigned last is compared with the position on the B-scope image, and when the distance between the two is within a predetermined range, the assigned assigned number is assigned to the detected reflected echo. Further, when an assigned number that has already been used is not assigned to the reflected echo detected under the above condition, an unused assigned number is assigned to the detected reflected echo.
[0024]
By this processing procedure, a different allocation number is assigned to each connected area on the B scope image, and the connected area is extracted. Note that the connection condition may be that the pixels when the reflection echo is provided are adjacent to each other and, for example, the number of pixels when there is no reflection echo existing between the pixels when the reflection echo is provided is equal to or less than a predetermined number. . In this case, even if the reflected echo is somewhat lost, it can be regarded as one connected region.
[0025]
Next, the feature amount extraction unit 15 uses the size, end point position, and connection region on the B scope image as the feature amount of the connection region on the B scope image of the reflected echo extracted by the connection region extraction unit 14. A representative value of the reception signal level of the reflection echo that constitutes is obtained. First, the positions of both end points of the connected region are determined on the respective B scope images of the reflected echo assigned first with a certain assigned number and the reflected echo assigned last in the connected region extraction processing of the connected region extracting unit 14. It is calculated as the position at. Moreover, the magnitude | size of a connection area | region is calculated | required as a distance between both end point positions, for example.
[0026]
Furthermore, the representative value of the reception level of the reflection echo that constitutes the connection area may be, for example, the maximum value of the reception signal level of the reflection echo that constitutes the connection area. Note that the feature amount extraction unit 15 may have a function of performing the following correction on the size of the connected area and the representative value of the reception signal level of the reflected echo that forms the connected area.
In this correction, the beam width is subtracted from the size of the connected region in order to eliminate the influence of the spread of the beam width of the ultrasonic pulse. For simplicity, the beam width may be a constant value and a predetermined value may be subtracted. More precisely, in consideration of the fact that the beam width increases as the distance from the ultrasound probe 11 increases, the beam width is determined in advance as a function of the beam path length, and the beam of the reflected echo constituting the connection region is determined. The beam width with respect to the representative value of the path length may be subtracted.
[0027]
As a representative value of the beam path of the reflected echo constituting this connection area, for example, the beam path of the reflection echo located at the center of gravity of the connection area is used. Here, the center of gravity is defined as a moment feature. For example, it can be simply calculated as the center of both end points. Further, as a representative value of another beam path, a beam path of a reflected echo having a reception signal level having a minimum difference from a representative value of a reception signal level of a reflected echo constituting the connection region may be employed. This is the beam path of the reflected echo of the maximum received signal level when the maximum value of the received signal level of the reflected echo constituting the connection region is used as a representative value.
[0028]
Next, with respect to the representative value of the reception signal level of the reflection echo constituting the connection region, for example, a non-decreasing function for the beam path length is considered in consideration of the broadening of the beam width of the ultrasonic pulse and the attenuation of energy. A certain positive correction coefficient may be determined in advance and multiplied by a correction coefficient for the representative value of the beam path length of the reflected echo constituting the connected region. Here, as the representative value of the beam path of the reflection echo constituting the connection region, the above-described representative value may be used.
[0029]
In the determination unit 16, the size of the reflection echo extracted by the feature amount extraction unit 15 on the B scope image, which is the feature amount of the connection region on the B scope image, the end point position, and reception of the reflection echo constituting the connection region Based on the representative value of the signal level, the severity of the flaw that is the reflection source of the reflection echo constituting the connection region is determined.
The specific determination method of the seriousness of this flaw is, for example, that the size of the connection region is L, the distance from the surface of the rail 10 farther from the surface of the rail 10 at both end points is D, the received signal level Assuming that the representative value is H and the predetermined coefficients are k1, k2 and k3, an index S representing the seriousness of the flaw is calculated by the following equation (1). Severity is determined by the value of this index S.
[0030]
S = k1 · L + k2 · D + k3 · H (1)
The determination result of the seriousness of the flaw along with the flaw position obtained in this way is displayed on the screen by the display unit 17 and the recording unit 18, stored in the hard disk, and further output as a hard copy.
[0031]
【The invention's effect】
As is clear from the above description, according to the inspection object wound determination method and apparatus of the present invention, determination is made for each connected region on the B-scope image of the reflected echo. Further, since the determination is made using the size on the B scope image instead of the conventional defect instruction length, the evaluation is performed with the actual size of the scratch regardless of the angle of the scratch. In addition to the size of the scratch on the B scope image, the received signal level is also used to estimate the size of the scratch, and the depth of the scratch from the surface by focusing on the end point position. Is taking into account. As a result, it becomes possible to determine the severity of individual scratches with high reliability.
[0032]
In addition, the correction of the beam width is performed for the size of the scratch on the B scope image, and the correction according to the beam path considering the spread and attenuation of the beam width is performed for the reception signal level. The size of the flaw can be estimated more accurately.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of an embodiment of an inspection object wound determination method and apparatus according to the present invention. FIG. 2 is a perspective view showing a measurement state when a railroad rail is ultrasonically detected in a conventional example. FIG. 3 is a block diagram showing a configuration of a conventional ultrasonic flaw detector. FIG. 4 is a diagram for explaining a detection state in which there are two flaws on a rail in the conventional example. FIG. FIG. 6 is a diagram for explaining a detection state of coincidence or mismatch between the instruction length and the actual scratch size. FIG. 6 illustrates a detection state in the conventional example in which the defect instruction length is longer than the actual scratch size. FIG. 7 is a diagram for explaining a detection state of a beam range and a flaw size in a conventional example.
10: Rail 11: Ultrasonic probe 12: Ultrasonic transmission / reception unit 13: Reflected echo detection unit 14: Connection region extraction unit 15: Feature amount extraction unit 16: Determination unit 17: Display unit 18: Recording unit 19: Movement distance Sensor

Claims (14)

In the inspection object wound determination method for determining a wound of the inspection object from a reflected echo obtained by radiating an ultrasonic pulse to the inspection object,
The connected area of the reflected echo on the B scope image is extracted, and the size, end point position, and received signal level of the reflected echo constituting the connected area as the feature amount of the extracted connected area are extracted. A method for determining a wound to be inspected, characterized in that a representative value is obtained, and then the severity of a wound which is a reflection source of a reflection echo constituting the connection region is determined based on the feature amount. In the inspected object wound determination method according to claim 1,
A method for determining an object to be inspected, wherein the representative value of the reception signal level of the reflection echo constituting the connection area is the maximum value of the reception signal level of the reflection echo constituting the connection area. In the inspected body wound determination method according to claim 1 or 2,
A method for determining an inspection subject wound, comprising: correcting a size of the connected region on a B-scope image by subtracting a beam width of the ultrasonic pulse. 4. The inspected object wound determination method according to claim 1, 2, or 3, wherein a representative value of a beam path length of a reflected echo constituting the connection area is further obtained as the extracted feature quantity of the connection area, and the connection area is determined. Is corrected so that the representative value of the received signal level becomes smaller as the representative value of the beam path of the reflected echo constituting the connected region is smaller than the representative value of the received signal level of the reflected echo constituting A method for determining a wound to be inspected. In the inspection subject wound judgment method according to claim 4,
A method for determining an object to be inspected, wherein a representative value of a beam path of a reflection echo constituting the connection area is set to a beam path of a reflection echo positioned at the center of gravity of the connection area. In the inspection subject wound judgment method according to claim 4,
The representative value of the beam path of the reflected echo constituting the connected area is set to the beam path of the reflected echo having the minimum difference between the received signal level of the reflected echo constituting the connected area and the representative value. A method for determining a wound to be inspected as a feature. In the inspected object wound determination apparatus for determining a wound on the inspected object from a reflected echo obtained by radiating an ultrasonic pulse to the inspected object,
A reflection echo detector for detecting a reflection echo from a reception signal of reflection of an ultrasonic pulse radiated to the inspection object;
A connected region extracting unit for extracting a connected region on the B scope image of the reflected echo detected by the reflected echo detecting unit;
A feature amount extraction unit that extracts a representative value of a reception signal level of a reflection echo that constitutes the size, the end point position, and the reflection region constituting the connection region as a feature amount of the connection region extracted by the connection region extraction unit; ,
Based on the feature amount extracted by the feature amount extraction unit, a determination unit that determines the severity of a scratch that is a reflection source of the reflection echo that configures the connected region;
A device for determining an object to be inspected is provided. In the inspected wound determination device according to claim 7,
The inspected object scratch characterized in that the representative value of the reception signal level of the reflection echo constituting the connection area extracted by the feature amount extraction unit is set to the maximum value of the reception signal level of the reflection echo constituting the connection area. Judgment device. In the inspected wound determination device according to claim 7 or 8,
The inspection object wound determination apparatus, wherein the feature amount extraction unit performs correction by subtracting a beam width of the ultrasonic pulse with respect to a size of the connection region on a B-scope image. In the inspected wound determination apparatus according to claim 7, 8 or 9,
The feature amount extraction unit further obtains a representative value of the beam path of the reflected echo constituting the connection region as the feature amount of the connection region extracted by the connection region extraction unit, and also reflects the reflection echo constituting the connection region. The received signal level is corrected so that the representative value of the received signal level becomes smaller as the representative value of the beam path of the reflected echo constituting the connected region is smaller. Inspection body wound judgment device. In the inspected wound determination apparatus according to claim 10,
Inspected object wound determination apparatus characterized in that a representative value of a beam path of a reflection echo constituting the connection area extracted by the feature amount extraction unit is a beam path of a reflection echo positioned at the center of gravity of the connection area. . In the inspected wound determination apparatus according to claim 10,
Reflection of the received signal level with the smallest difference between the representative value of the beam path of the reflected echo constituting the connected area extracted by the feature amount extraction unit and the representative value of the received signal level of the reflected echo constituting the connected area. An inspection object wound determination apparatus characterized by having an echo beam path length. Claim 7, in the test subject wound-size TeiSo location of 8, 9, 10, 11 or 12, wherein,
Device under test scratch-format TeiSo location, wherein the object to be inspected is rail. Claim 7, the device under test scratch-format TeiSo location of 8, 9, 10, 11 or 12, wherein the test subject wound-size constant, characterized in that applied to the rail flaw determination unit in the ultrasonic rail flaw detection vehicles equipment.

Images