JP3384863B2 - Evaluation method of defect height in radiation transmission test, reference body for evaluation of defect height, and evaluation device for defect height - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect height evaluation method, a defect height evaluation reference body, and a defect height evaluation apparatus in a radiation transmission test of steel plates, steel pipes, and the like.

[0002]

2. Description of the Related Art Conventionally, as a method for evaluating the height of a defect in a radiation transmission test, a stereoscopic photographing method, an oblique photographing method, a three-direction photographing method and the like are known. However, according to these conventional methods, when there is a defect in a transmission photograph obtained by one-time photographing, the defect height cannot be directly evaluated from the transmission photograph itself. Therefore, it is necessary to take a transmission photograph of the defective portion again by changing the irradiation direction of the radiation, and not only taking the trouble of taking the photograph again,
The positional relationship when shooting with changing the irradiation direction had to be set very accurately, and the shooting was extremely difficult on site.

[0003]

In view of such a problem,
A first object of the present invention is to provide a defect height evaluation method and an evaluation device in a radiation transmission test, which can accurately evaluate the defect height by one imaging. A second object of the present invention is to provide a defect height evaluation reference body that improves workability when capturing a transmission image.

[0004]

In order to achieve the above first object, the first characteristic configuration of the defect height evaluation method according to the present invention is to irradiate a test body with radiation and at the same time, use a photographing means to test the test body. In the method for obtaining the height of the defect portion S3 ′ shown in the taken transmission image by taking a transmission image of the reference image, a reference piece having a property that is radiologically equivalent to that of the test object is superposed on the test object, and then taken. This is to find the defect height X by an equation. X = ln {(D ₂ '-b) / (D ₁ -b)} ・ ΔT / [ln {(D ₂ -b) / (D ₁ -b)} ・ Q] However, D ₂ ' is the above-mentioned photographing The reaction amount of the portion S3 corresponding to the defective portion S3 ′ in the means, D ₁ is the reaction amount of the portion S1 corresponding to the normal portion S1 ′ in the photographing means, and D ₂ is the normal portion and the reference piece in the photographing means. Of the reaction amount of the portion S2 corresponding to the overlapping portion S2 ', b is the background amount of the reaction amount in the photographing means, ΔT is the thickness of the reference piece, and Q is the reference coefficient determined in advance.

A second characteristic construction of the defect height evaluation method is the same as the first characteristic construction, wherein the photographing means comprises a radiation film, and the reaction amount is a transmission photographic density photographed on the radiation film. Yes, the background amount b of the reaction amount is the fog density of the transmission photograph taken on the radiation film.

On the other hand, the characteristic structure of the reference body for evaluating the defect height according to the present invention is such that the surface of the reference piece described in either the first or second characteristic structure is aligned with the surface of the test body. This is because the reference member is supported by the support member and a material having a smaller radiation absorption rate than that of the reference member is used for the support member.

Further, the characteristic construction of the defect height evaluation apparatus for a radiation transmission test according to the present invention is a photographing means for photographing a transmission image obtained by irradiating a test body with radiation, and a photographing means. And a display device for displaying the processing result of the processing device, wherein the processing device stores the reaction amount D of a portion corresponding to each test target portion in the imaging device. Photographed image storage means and a portion S1 corresponding to a normal portion in the photographing means
Of the reaction amount D ₁ and the reaction amount D ₂ of the portion S2 corresponding to the overlapping portion of the normal portion and the reference piece in the photographing means from the reaction amount D stored in the photographed image storage means. Means, parameter determining means for determining the reference coefficient Q and the thickness ΔT of the reference piece, which have been obtained in advance, BG detecting means for obtaining the background amount b of the reaction amount in the photographing means, and the photographed image storage means. The reaction amount conversion means for converting the reaction amount D into the defect height X by the following equation and displaying the defect height X as an absolute amount on the display device is provided. X = ln {(D-b) / (D ₁ -b)} ・ ΔT / [ln {(D ₂ -b) / (D ₁ -b)} ・ Q]

[0008]

According to the inventor's experiment, ln {(D ₂ '-b) / (D ₁ -b)}
The value of is approximately proportional to the known defect height ΔT ', and the value of the equation ln {(D ₂
The value of -b) / (D ₁ -b)} was found to be approximately proportional to the thickness ΔT of the reference piece. Therefore, it can be considered that the following relationship is established (see FIG. 3A). ln {(D ₂ '-b) / (D ₁ -b)} = q ₂ ' ・ ΔT '(a) ln {(D ₂ -b) / (D ₁ -b)} = q ₂・ ΔT (B)

By the way, the reaction amount _{D 1, D 2, D 2} ' and the reference amount b is the proportionality constant q ₂ of formula for varying the shooting conditions (a)' and Formula proportional constant q ₂ of (b) The absolute value also changes depending on the shooting conditions. However, the ratio of the proportionality constant q ₂ 'and the proportionality constant q ₂ measured under the same shooting conditions Q = q ₂ ' / q ₂
The value of is a constant peculiar to the thickness of the test piece and the area of the reference piece.

Therefore, a defect having a known defect height ΔT 'in place of the unknown defect height X and a test body having a known thickness, and a reference piece having a known thickness ΔT and a known area are used. _{, Q = q 2 '/ q} 2 = [ln {(D 2' -b) / (D 1 -b)} / ΔT '] / [ln {(D 2 -b) / (D 1 -b)} / ΔT] (c) The reference coefficient Q is calculated in advance.

Furthermore, by actually photographing, each reaction amount D ₁ ,
When D ₂ , D ₂ 'and the reference amount b are obtained and the reference coefficient Q according to the thickness of the test piece and the area of the reference piece used at the time of this photographing is selected, the following equation is established (see FIG. 3 (b)). ). Q = [ln {(D ₂ '-b) / (D ₁ -b)} / X] / [ln {(D ₂ -b) / (D ₁ -b)} / ΔT] (d)

By transforming the above equation, X = [ln {(D ₂ '-b) / (D ₁ -b)}] ΔT / [ln {(D ₂ -b) / (D ₁ -b) } · Q] (e), the unknown defect height X can be obtained. The value of the reference coefficient Q is a value including Q = 1 as described later.

Therefore, according to the first characteristic configuration of the above defect height evaluation method, the unknown defect height X can be obtained from the photographed image obtained by one photographing. Moreover, since the formula (e) is established without being affected by the intensity of radiation, the unknown defect height X can be accurately evaluated even if the intensity of the radiation source and the irradiation time are different each time an actual image is taken. can do.

According to the second characteristic configuration of the above evaluation method, the defect height is evaluated based on the density of the transmission photograph taken on the radiation film, but the exposure amount of the entire transmission photograph differs for each photographing. However, the absolute evaluation of the unknown defect height X is possible.

By the way, when the area of the reference piece becomes small, the reference coefficient Q becomes almost 1 and the trouble of selecting the reference coefficient can be saved, but it is difficult to make the surface of the small reference piece follow the surface of the test body. Also, it is easy to lose and inconvenient to handle. According to the characteristic configuration of the defect height evaluation device, since the reference piece is supported by the supporting member for aligning the surface of the reference piece with the surface of the test piece, the reference piece can be easily attached and handled. Become. Moreover, since the support member is made of a material having a smaller radiation absorption rate than the reference piece, it is difficult to interfere with photographing.

On the other hand, according to the characteristic structure of the defect height evaluation device, the reaction amount extraction means is configured so that the reaction amount D ₁ of the stored reaction amount D is the reaction amount D _{1, of} the portion corresponding to the normal portion and the overlapping portion _.
Extract D ₂ . Further, the reference coefficient Q, the thickness ΔT of the reference piece, and the background amount b are obtained by the parameter determining means and the BG detecting means. Then, by the reaction amount conversion means, the defect height X is the same as in the first characteristic configuration of the evaluation method.
Can be obtained and the value is displayed as an absolute quantity.

[0017]

As described above, according to the characteristic structure of the defect height evaluation method and the defect height evaluation apparatus according to the present invention, the defect height can be accurately evaluated by one photographing. Became. Further, according to the characteristic structure of the defect height evaluation reference body, the reference piece can be easily handled and the workability in capturing a transmission image can be improved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a defect height evaluation method in a radiation transmission test according to the present invention will be described below with reference to the drawings. In this embodiment, X-rays are used as the radiation, and the X-ray film 4 is used as the radiation film of the photographing means.

FIG. 1 is a conceptual diagram showing an outline of the test equipment used when obtaining the reference coefficient Q and when obtaining the unknown defect height X. The test facility includes an X-ray irradiator 1, which is a radiation source for irradiating X-rays, and a known defect height Δ.
A test piece 2 having a defect S3 'of T'and having a constant thickness T1, and a reference piece 3 superposed on the test piece 2.
There is provided an X-ray film 4 as a photographing means which is arranged in close contact with the surface of the test body opposite to the radiation source. In this embodiment, a steel plate made of carbon steel SM490A is used as the test body 2, and a small plate made of stainless steel SUS304 having the same radiation properties as the carbon steel SM490A is used as the reference piece 3. The test piece 2 can evaluate not only carbon steel, high-strength steel, stainless steel, but also aluminum and the like, and the material of the reference piece 3 has the same radiation property as the test piece 2. There is enough.

As the reference piece 3, a gradation meter used at the time of photographing the radiation transmission test can be used. The reference piece 3 has a square shape in a plan view and has a constant thickness ΔT. The thickness ΔT of the reference piece 3 and the length L of one side in plan view can be changed for each test. It is desirable that the reference piece 3 be superposed on the test body 2 as closely as possible, and the reference piece 3 may be superposed on either the radiation source side surface or the film side surface of the test body 2, but if the superposition side is different. The reference coefficient Q is different. It is desirable that the reference piece 3 be positioned as close to the center of the X-ray film as possible for photographing. The reference piece 3 can usually be attached with an adhesive tape or the like.

As for the gradation meter, it is usual to use one having a side length of about 15 mm or more in a plan view, but as will be described later, if the area of the reference piece 3 in a plan view becomes small, the reference While the coefficient Q is approximately 1 to facilitate the evaluation of the defect height, the reference piece 3 is easily tilted or lost, which is inconvenient to handle. Therefore, when the length of one side of the reference piece 3 is as short as 5 mm or less,
As shown in (a) and (b), the reference piece 3 is supported by a support member 5 for aligning the surface of the reference piece 3 with the surface of the test piece 2 to form a defect height evaluation reference body 6. There is. A film made of a material having a smaller radiation absorption rate than the reference piece 3, for example, a resin film such as vinyl chloride or nylon is used as the support member 5 so as not to interfere with photographing. In supporting the reference piece 3 on the resin film serving as the support member 5, the reference piece 3 is attached onto the resin film 5 as shown in FIG. 4A, and the resin film is also shown as shown in FIG. You may embed the reference piece 3 in 5. When the surface of the test body 2 is curved, it is desirable that the support member 5 is made of a flexible material. However, when the surface of the test body 2 is flat, the support member 5 is made of a rigid member. Good.

Next, a transmission image of the point S1 on the film by the X-ray that has passed only the normal portion S1 'of the test piece, and a point S on the film by the X-ray that has passed the overlapping portion S2' with the reference piece.
Consider the transmission image of No. 2 and the transmission image of the point S3 on the film by the X-ray that has passed through the defect portion S3 ′. The irradiation dose E ₁ that reaches the point S1 on the X-ray film is represented by the following equation.

[0023]

[Equation 1]

Where I ₀ : point S1 when there is no test body
Radiation dose μ ₁ : Linear absorption coefficient n ₁ : Scattering ratio of the specimen. The quotient of the scattered dose rate reaching point S1 multiplied by the sensitivity coefficient of the X-ray film divided by the transmission dose rate reaching point S1 multiplied by the sensitivity coefficient of the X-ray film. t: X-ray exposure time

By the way, when the cross-sectional area of the defect portion S3 'is small, the scattered dose rates at the points S1 and S3 are substantially equal, and the scattered dose rate at the point S2 is equal to the scattered dose rate at the point S1 by a correction coefficient P. Expressed as a value multiplied by. Therefore, the scattering ratios n ₂ and n ₂ 'at the points S2 and S3, respectively, are affected by the increase or decrease of the transmitted dose rate and are respectively expressed by the following equations.

[0026]

[Equation 2]

Here, the correction coefficient P is a coefficient for correcting the scattering ratio at the overlapping portion with the reference piece, and is the length of one side of the reference piece, the thickness of the test piece, and the position of the reference piece (test. It is a value that varies depending on whether the body is placed on the side of the radiation source or on the side of the film. Therefore, the irradiation dose E ₂ 'at the point S3 corresponding to the defective portion is expressed by the following equation.

[0028]

[Equation 3]

The transmission photographic density D of the X-ray film is
It is directly proportional to the irradiation dose E and is represented by the following equation. D = aE + b (j) Here, a: proportional constant, b: fog density of the X-ray film.

From the formulas (f), (i) and (j), the transmission photographic density D _{1 at} the point S1 corresponding to the normal portion and the transmission photographic density D ₂ 'at the point S3 corresponding to the defective portion are respectively expressed by the following equations. It is represented by.

[0031]

[Equation 4]

From the equations (k) and (l), the following equation is obtained.

[0033]

[Equation 5]

The linear absorption coefficient μ varies depending on the thickness T1 of the test piece and is represented by the following equation. μ = cT ₁ ^d (n) where c and d are constants that vary depending on the energy of radiation, the range of the thickness of the test body, and the material of the test body. Substituting the result of expression (n) into expression (m) gives the following expression.

[0035]

[Equation 6]

Further, similarly to the equation (o), the following equation is obtained.

[0037]

[Equation 7]

When equations (o) and (p) are calculated, FIG.
As shown in, the value of ln {(D ₂ '-b) / (D ₁ -b)} is approximately linearly proportional to the known defect height ΔT', and the expression ln {(D ₂ -b) / (D _1-
It was found that the value of b)} is almost linearly proportional to the thickness ΔT of the reference piece, and the experimental result of the inventor is linearly proportional to the calculated result. Therefore, as described above, FIG.
The reference coefficient Q can be obtained in advance from (a) and the equation (c), and the unknown defect height X can be obtained from FIG. 3 (b) and the equation (e). That is, point A in FIG.
1 and A2, the value of the reference coefficient Q is obtained, and the point B in FIG.
The unknown defect height X can be calculated by identifying the point B3 from the values of 1 and the reference coefficient Q and determining the point B2.
If the known thickness ΔT of the reference piece is equal to the known height of the defect, the reference coefficient Q can be obtained from the points A1 and A3.

In specifying each photographic density, for example, the point S1
The transmission photographic density D ₁ can be specified by adjusting the exposure amount, and the transmission photographic density D _{2 at the} point S2 can be determined by a densitometer.
The transmission photographic densities D ₂ 'at point S3 may be measured by a microdensitometer. The transmission photographic density D _{2 at} the point S2 is measured at the portion corresponding to the center of the reference piece.

FIG. 4 is a graph showing changes in the reference coefficient when the type of radiation, the thickness T1 of the test piece and the length of one side of the reference piece are used as parameters. From this result, the reference coefficient Q changes depending on the thickness T1 of the test body and the length of one side of the reference piece, but does not change depending on whether the type of radiation is X-rays or γ-rays such as iridium. I understand. In particular, the length of one side of the reference piece in plan view is 2.
In the case of 5 mm, since the reference piece is small and it is difficult for the scattered radiation to be blocked, the correction coefficient P in the equation (g) increases,
The reference coefficient Q becomes close to 1. That is, it is sufficient to consider in advance only the thickness ΔT of the reference piece used in the actual photographing, and thus the defect height can be easily derived. According to another experiment by the inventor, in order to treat the reference coefficient Q as 1,
The length L of one side of the reference piece is preferably 0.5 mm or more 4
mm or less, and more preferably 1 mm or more and 3 mm or less. If the length of one side is larger than the upper limit value, the reference coefficient Q becomes a value that cannot be regarded as 1, and in order to measure the concentration of the portion P2 corresponding to the overlapping portion with the reference piece by the densitometer, A general-purpose densitometer with a side length of 1 mm
This is because the above is necessary, and if the length of one side is less than 0.5 mm, it becomes difficult to measure even with a special densitometer.

Next, a second embodiment of the present invention will be described. This embodiment relates to a defect height evaluation apparatus for a radiation transmission test for realizing the above defect height evaluation method.

FIG. 5 is a functional block diagram showing the basic structure of the evaluation apparatus. This evaluation apparatus 10 is an imaging means for imaging a transmission image obtained by irradiating the test body 2 with radiation. The apparatus 12 includes a processing device 14 for processing a transparent image captured by the imaging device, and a monitor 16 as a display device for displaying the processing result of the processing device.

As shown in FIGS. 5 and 6, the processing device 12 includes a photographed image storage means 18 for storing a reaction amount D of a portion corresponding to each test target portion in the photographing device, and a normal photographing device. Reaction amount of part S1 corresponding to part S1 '
D ₁ and the overlapping part S between the normal part and the reference piece 3 in the imaging device
Reaction amount extraction means 20 for extracting the reaction amount D ₂ of the portion S2 corresponding to 2 ′ from the reaction amount D stored in the photographed image storage means
And the reference coefficient Q and the thickness Δ of the reference piece 3 obtained in advance.
Parameter determining means 22 for determining T, and the photographing device 12
BG detection means 24 for obtaining the background amount b of the reaction amount in the above, and the reaction amount D stored in the photographed image storage means 18 are converted into the defect height X by the following equation (q) and the defect height X is monitored. 16 is provided with a reaction amount conversion means 26 for displaying as an absolute amount. The defect height X in the present embodiment corresponds to the reaction amount of the portion corresponding to each test target portion, and X = 0 in the portion S1 corresponding to the normal portion as in the first embodiment. different. X = ln {(D−b) / (D ₁ −b)} · ΔT / [ln {(D ₂ −b) / (D ₁ −b)} · Q] (q)

As shown in FIG. 6, the above-mentioned photographing apparatus includes an image intensifier 42 for converting a perspective image by transmission X-rays into an image of visible light and a CCD image pickup device for photographing the output of the image intensifier. 44 and C
An optical lens 46 for forming an output image of the image intensifier on the light receiving surface of the CD image. The image intensifier first converts incident X-rays into visible light on the input phosphor screen 42a, then converts them into photoelectrons on the photocathode 42b, and forms an image on the output phosphor screen 42c with an electronic lens (not shown). In this embodiment, the reaction amounts D, D ₁ and D ₂ are C
This corresponds to the amount of electron emission caused by the light hitting the photodiode that constitutes the CD image pickup device 44.

FIG. 8 is a sectional view 17 showing the distribution of defect heights X displayed on the monitor 16 by the processing of the reaction amount conversion means 20. This reaction amount conversion means is configured such that the position of the display cross section can be selected by the display cross section changeover switch 28, and the required reaction amounts D ₁ and D ₂ , the thickness ΔT of the reference piece 3 and the reference coefficient Q, etc. When the parameter is determined, the reaction amount D stored in the photographed image storage unit 18 is converted into the defect height X by the above equation (q), and the defect height X is displayed as an absolute amount on the monitor. Two-dimensional display is performed together with the display gauge 17a. However, before the parameters are determined, the reaction amount D is two-dimensionally displayed as a relative value without being converted, and the display range can be switched by the range switch 30. The coordinates of each point in the cross section display can be specified by the positions of the horizontal gauge 17b and the cross section changeover switch.
In FIG. 8, an example of a cross-sectional display is shown, in which 17c is a crack, 17d is a welded portion, 17e is a blow hole, and 17f is a reference piece.

The reaction amount extracting means 20 shown in FIG. 5 is a coordinate input unit 32 for visually selecting a portion corresponding to the normal portion and the overlapping portion on the cross-section display screen of FIG. 8 and inputting the coordinates thereof. Is equipped with. Further, the reaction amount extraction means 2
0 represents the reaction amounts D1 and D2 of the normal part and the part corresponding to the overlapping part from the reaction amount D of each test target part stored in the photographed image storage means 18 based on the coordinates input by the coordinate input part 32. A transfer unit 34 for selecting and transferring to the reaction amount conversion means is provided.

The parameter determining means 22 uses the reference piece 3
Parameter input key 36 for inputting the thickness ΔT and the length of one side and the thickness T1 of the test piece 2, the length of one side of the reference piece 3 in each record, the thickness T1 of the test piece 2 and the reference coefficient. It has a reference coefficient DB device 38 which is a database having Q as data fields. The reference coefficient DB device 38 searches for a record that matches the length of one side of the reference piece 3 and the thickness T1 of the test piece 2 input from the parameter input key, and determines the length of one side of the reference piece 3 and the test. A reference coefficient Q suitable for the thickness T1 of the body 2 is selected and output to the reaction amount conversion means 26. Parameter input key 36
The thickness ΔT of the reference piece 3 inputted from the reaction amount conversion means 2
Directly output to 6. The BG detection unit 24 recognizes the level of the output signal from the imaging device 12 as the background amount b of the reaction amount in the imaging unit when the X-ray is not irradiated.

Next, the operation of the evaluation apparatus will be described with reference to the flowchart of FIG. 7 and the monitor output screen of FIG. When the evaluation device is activated, the BG detection means 24 detects the background amount b (step N1). Next, when the photographing is started (step N2), the photographed image storage means 18 stores the reaction amount D in each test target portion of the photographed image (step N3), and the reaction amount memo conversion means 26 follows the display cross section changeover switch 28 to display the display cross section. Is selected (step N4), two-dimensional display processing is performed (step N5), and the monitor 16 is displayed in the display range corresponding to the range changeover switch 30.
Then, two-dimensional display is performed using each reaction amount D as a relative value (step N6).

While referring to the display on the monitor 16, the coordinates of the highest portion and the normal portion of the overlapping portion are selected, and the coordinate input portion 3 is selected.
When designated input from 2 (step N6), the reaction amount transfer section 34 selects the reaction amounts D ₁ and D ₂ of the portions S1 and S2 corresponding to the normal portion and the overlapping portion and transfers them to the reaction amount conversion means 26. These coordinates are selected by sequentially switching the display sections by switching the display section changeover switch 28. Then, the parameter input key 36 is pressed to set the thickness ΔT of the reference piece 3.
When the length of one side and the thickness T1 of the test body 2 are input (step N8), the reference coefficient DB means 38 retrieves and determines the reference coefficient Q that meets the conditions, and the reference coefficient Q is converted into the reaction amount conversion means 26. Output to. The reaction amount conversion means 26 converts the reaction amount D stored in the photographed image storage means 18 into the defect height X by the above equation (q) (step N9), and selects the display cross section similarly to step 4 (step N10). ), Two-dimensional display processing is performed (step N11), and the defect height X is two-dimensionally displayed together with the gauge on the monitor 16 as an absolute amount (step N12).

Next, a modified example of the present invention will be described.
A fluorescent plate or MCP may be used in place of the image intensifier 42 in the photographing device 12, and a MOS type image pickup device or a vidicon may be used in place of the CCD image pickup device as the image pickup device. When an image intensifier or a fluorescent screen is used, the defective portion is displayed brighter than the normal portion, contrary to the case of the X-ray film.

When the respective reaction amounts do not have a linear relationship with the irradiation dose, the value after correction by the correction means is the reaction quantity, and the image pickup device includes the image pickup device and the correction means. . Further, the case where the correction means has a function for linearizing and the function of the equation (q) as an integral function is also included in the reaction amount conversion means described in the claims of the present invention. is there.

The parameter determining means 22 may be configured to directly input the thickness ΔT of the reference piece 3 and the reference coefficient Q. Further, when the length of one side of the reference piece is 4 mm or less, the reference coefficient Q can be fixed to 1. Therefore, it is not necessary to specify Q in the parameter determining means.
The reference coefficient DB device is also unnecessary. Reaction amount extraction means 20
Is configured to automatically extract the reaction amount of the portion corresponding to the normal portion and the reaction amount of the portion corresponding to the overlapping portion from the reaction amount D of the portion corresponding to each test target portion stored in the photographed image storage unit 18. May be The display device is not limited to a monitor and may be a printer or the like, and the display by the display device is
Not only two-dimensional display but also three-dimensional display may be used.

In the above-mentioned first embodiment, the reference piece was attached to the sheet-like support member in constructing the reference body. However, as shown in FIG. 9 (b), the defect height of the steel pipe 2 as the test body was measured. In the case of evaluation, a strip-shaped resin tape 5 is used as a supporting member as shown in FIG. 3A, the reference piece 3 is attached to the resin tape 5, and a hook tape 5a is attached to each end of the resin tape 5. The reference body 6 may be configured by attaching a surface fastener 5c (trademark name Velcro tape) including the loop tape 5b.

[Brief description of drawings]

FIG. 1 is a side view conceptually showing a test facility for carrying out the present invention (first embodiment).

FIG. 2 is a perspective view showing a reference body.

3A is a graph for explaining a principle of obtaining a reference coefficient Q, and FIG. 3B is a graph for explaining a principle of deriving an unknown defect height X.

FIG. 4 is a graph showing the value of a reference coefficient Q when the length of one side of the reference piece, the thickness of the test piece, and the type of the radiation source are used as parameters.

FIG. 5 is a functional block diagram showing a basic configuration of an evaluation device (second embodiment).

FIG. 6 is a conceptual diagram showing a configuration of a photographing device.

FIG. 7 is a flowchart showing the operation of the evaluation device.

FIG. 8 is a sectional view displayed on a monitor.

FIG. 9 shows a modified example of the reference body, (a) is a plan view,
(B) is a longitudinal sectional view showing a state in which a reference body is wound around a tube and an image is taken.

[Explanation of symbols]

2 Specimen 3 Reference piece 4 Imaging means S3 'Defect portion X Defect height S1 Part S2 corresponding to normal portion in imaging means S2 Part corresponding to overlapping portion of normal portion and reference piece in imaging means S3 Defect portion in imaging means The part corresponding to.

Claims (4)

(57) [Claims] 1. The height of a defect portion (S3 ′) shown in the photographed transmission image obtained by irradiating the specimen (2) with radiation and photographing the transmission image of the specimen (2) by the photographing means (4). Is a method of evaluating the height of a defect in a radiation transmission test, in which a reference piece (3) having a property that is radiologically equivalent to that of the test body (2) is superposed on the test body (2) and photographed. A defect height evaluation method in a radiation transmission test for obtaining a defect height (X). X = ln {(D ₂ '-b) / (D ₁ -b)} ・ ΔT / [ln {(D ₂ -b) / (D ₁ -b)} ・ Q] However, D ₂ ' is the above-mentioned photographing Defective part (S
The reaction amount of the portion (S3) corresponding to 3 '), D ₁ is the portion (S1) corresponding to the normal portion (S1') in the photographing means (4).
1) the reaction amount, D ₂ is the reaction amount of the portion (S2) corresponding to the overlapped portion (S2 ′) between the normal portion and the reference piece (3) in the photographing means (4), and b is the photographing means. The background amount of reaction amount in (4), ΔT is a reference piece (3)
Thickness, Q is the standard coefficient determined in advance. 2. The photographing means comprises a radiation film (4), the reaction amount is a transmission photographic density photographed on the radiation film (4), and the background amount b of the reaction amount is the radiation film (4). The method for evaluating the height of a defect in a radiation transmission test according to claim 1, wherein the fog density is a transmission photograph taken in 4). 3. A defect height evaluation reference body having a reference piece used in the evaluation method according to claim 1, wherein the surface of the reference piece (3) is a test piece (2). The reference piece (3) is attached to the supporting member (5) for fitting along the surface of the
And an evaluation reference body for the defect height in which the support member (5) is made of a material having a smaller radiation absorption rate than the reference piece (3). 4. A photographing means (12) for photographing a transmission image obtained by irradiating a test body (2) with radiation.
And a processing device for a transparent image photographed by the photographing means (1
4) and a display device (16) for displaying the processing result of this processing device, and the processing device stores the reaction amount (D) of a portion corresponding to each test target portion in the imaging device. The photographed image storage means (18), the reaction amount (D ₁ ) of the portion (S1) corresponding to the normal portion (S1 ′) in the photographing means, the normal portion in the photographing means, and the reference piece (3) The part (S2 ') corresponding to the overlapping part (S2')
A reaction amount extraction means (20) for extracting the reaction amount (D ₂ ) of 2) from the reaction amount (D) stored in the photographed image storage means (18), and a reference coefficient (Q) and a reference piece determined in advance. Parameter determining means (22) for determining the thickness (ΔT) of (3), and BG detecting means (24) for determining the background amount (b) of the reaction amount in the photographing means (12).
And the reaction amount (D) stored in the photographed image storage means (18) is converted into the defect height X by the following formula and the defect height X is displayed on the display device (16) as an absolute amount. An apparatus for evaluating the height of a defect for a radiation transmission test, which comprises a conversion means (26). X = ln {(D-b) / (D ₁ -b)} ・ ΔT / [ln {(D ₂ -b) / (D ₁ -b)} ・ Q]