JP2019090740A - Radioscopic non-destructive inspection method and radioscopic non-destructive inspection apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine the size of an inspected object and an X-ray source from an imaged magnified image when the position of a point light source radiation source (focus) such as X-rays and the positional relationship between the receiver and the inspected object are unknown. Provided are a radiation fluoroscopic non-destructive inspection method and a radiation fluoroscopic non-destructive inspection apparatus capable of estimating the positional relationship (distance) between the subject and the subject to be inspected. SOLUTION: In the non-destructive inspection method of the present invention, two or more radiation fluoroscopic images at each position are acquired by changing the positional relationship between the radiation source and the irradiated object, and the size of the image on the image is obtained. Alternatively, using the measurement data of at least one of the changes in diameter and position and the distance data between the two positions of the radiation source and the receiver, the size of the object to be inspected, the magnification of the image, and the image are described. It is characterized in that at least one of the distances between the radiation source and the object to be inspected is geometrically calculated and estimated. [Selection diagram] Fig. 1

Description

  The present invention relates to a fluoroscopic nondestructive inspection method and fluoroscopic nondestructive inspection using a (quasi-) point source ionizing radiation source.

  In the medical and industrial fields, fluoroscopy of the human body and nondestructive inspection of structures using ionizing radiation are performed. Among the ionizing radiations, X-rays and gamma rays in particular are frequently used for nondestructive testing.

  Nondestructive testing using ionizing radiation is often performed by simple fluoroscopy or fluoroscopy from two directions, but computed tomography (CT) is also frequently performed. In this fluoroscopy, ionizing radiation is irradiated to the irradiated body, and information on the inside of the irradiated body is obtained from the intensity (transmittance) of the radiation transmitted through the irradiated body.

  In the case of simple fluoroscopy or fluoroscopy from two directions, the X-ray detector is often a two-dimensional detector. As a two-dimensional detector, an X-ray film or an imaging plate is used, but a flat panel detector (FPD) capable of electromagnetically transferring an image to a computer for online visualization and storage is also used. These x-ray detectors are generally referred to as receivers. The surface that senses x-rays in the receiver is called the image receiving surface.

  Generally, an object to be irradiated with ionizing radiation is referred to as an irradiated body. Moreover, although it is not a general expression, the area | region etc. which should be test | inspected inside a to-be-irradiated body shall be called a to-be-tested body here.

  In general, ionizing radiation such as X-rays limits the radiation field using a collimator or the like, and aligns the center of the radiation receiving surface with the center of the radiation field of the image receiver. For convenience, a line connecting the radiation source and the center of the radiation field or a perpendicular drawn from the top of the utilization line pyramid to the bottom is referred to as an irradiation axis. The utilization ray cone is a space irradiated with an X-ray or the like, and has a cone shape. The shape of the bottom of the cone depends on the shape of the collimator or the like, and can take any shape. The apex of the utilization cone coincides with the position (focus) of the radiation source. Also, the bottom surface of the utilization line means a surface that is considered to include or be included in the image receiving surface.

  By applying CT, it is possible to quantitatively evaluate the internal structure of the human body and structures. However, since CT requires a large amount of fluoroscopic image information to obtain a reconstructed image, there are problems in terms of imaging time and exposure. In addition, it is necessary to move the X-ray generator and the X-ray detector in a circular shape around the irradiated body or to rotate the irradiated body. In a medical CT apparatus, since it is not desirable to rotate a patient, an X-ray tube and an X-ray detector are arranged on a doughnut-shaped rotation stage to scan around the patient.

  As described above, CT is a very expensive method, and if it is not necessary to apply CT, it is customary to perform simple fluoroscopy. The cost referred to here includes not only the price of the device but also the labor and time required for imaging, exposure of the patient, and the like. Nondestructive inspection can not ignore worker exposure. There is no need to apply expensive CT if the required information can be obtained by simple fluoroscopy.

  However, in the case of simple fluoroscopy, the X-ray source is usually a (quasi-) point source, so there is a problem with magnification.

  Assuming that the distance from the position of the X-ray source (focus) to the inspection object is a and the distance from the X-ray source to the X-ray detector is b, the magnification is represented by b / a. For example, assuming that the size of the inspection object is d, the size D of the image on the image obtained on the image receiving surface of the image receiver can be obtained by d × b / a.

  If a and b are known, d can be estimated from D. However, if the exact position is unknown such as the test object which is a high density substance inherent to the irradiated body which is a low density substance, for example, a bone in a human body or a reinforcing bar in reinforced concrete, b may be known a is unknown and can not ask for d. For example, as shown in FIG. 10, even if high density material of the same size is inherent to low density material, the size of the image obtained by the X-ray detector varies depending on the distance from the X-ray source. Therefore, it is not possible to determine the exact size d of the high density material. In that case, assuming that a falls within a certain range, the range of possible values of d will be determined.

  In addition, as shown in FIG. 11, when high density material portions having different sizes are present at different positions on the same line along the X-ray irradiation axis direction, an image of the same size may be formed by the X-ray detector. is there. Also in this case, it is not possible to estimate the correct size d.

  As described above, CT can be used to determine the cross-sectional area of an object to be inspected, but CT is expensive. For example, in a reinforced concrete structure, it is ideal to accurately know the cross-sectional area of a reinforcing bar, but it is possible to obtain important information simply by being able to estimate the diameter (diameter, radius).

  In addition, if stereo imaging that photographs the same object in two or more directions is applied, the position of the object in FIG. 10 can be estimated, but the positional relationship between the X-ray source and the X-ray detector and the object is It is not possible to estimate the position of the part of the test subject unless In practical nondestructive testing this is not easy and costly.

  As another solution, the depth from the surface of the irradiated object is obtained by a method (for example, ultrasonic wave, infrared light or electromagnetic wave) capable of measuring the position of the object other than fluoroscopy by ionizing radiation (X-ray etc.) A method is also conceivable. However, in this case, it is necessary to wait for measurement by another method, and it may be more convenient to be able to estimate the position of the object by X-rays alone.

  In the case where a plurality of reinforcing bars are adjacent to each other within the imaging range with X-rays, for example, in the measurement using ultrasonic waves, it is not possible to determine which reinforcing bar the position in the depth direction of the reinforcing bars belongs to. Possible cases are conceivable.

  Furthermore, the position of the object to be inspected, which is a low density portion inside the object to be irradiated which is a high density substance such as a cavity in concrete, a cavity of a metal casting or a crack, is estimated by the same method as above. It is not always possible.

  In FIG. 10, the object to be inspected which is a high density substance inherent to the object to be irradiated which is a low density substance object is assumed. However, the object to be inspected is a low density portion which is inherent to the object to be irradiated which is a high density substance object. The same is true for the body.

  If a method of scanning the object one-dimensionally or two-dimensionally using so-called pencil beam X-rays is applied, it is not necessary to consider the magnification of the image, but it takes a lot of time for inspection.

  There is also a method of using X-rays as a fan beam (fan type) and using a line sensor as a receiver. In that case, it is not necessary to consider the enlargement factor for the scanning direction of the line sensor. However, with respect to the direction perpendicular to the scan axis, i.e. the direction in which the sensors are aligned, the problem of magnification occurs. Moreover, since it is necessary to scan even though it is a single axis, it takes time to obtain a two-dimensional image.

  In principle, X-rays can be regarded as parallel lines at a sufficient distance from the X-ray source (focus), so the problem of magnification can be ignored. However, a general X-ray source is a (quasi-) point light source, and the X-ray dose per unit area decreases in inverse proportion to the square of the distance. Therefore, imaging the X-ray source away from the irradiated object is disadvantageous in terms of imaging time. This is a problem that leads to radiation exposure to workers. In addition, it requires a corresponding space that encloses the X-ray source and the object to be irradiated.

  Patent Document 1 attempts to estimate the magnification of an image of an internal organ or the like from the thickness of a human body, but it is necessary to use distance estimating means for measuring the distance between the measurement target site and the image receiving surface in combination. Since it is not intended to estimate the position or magnification directly from only the image obtained by line imaging, the possibility of including an error can not be denied. In addition, since there is a precondition of the position of the viscera, if this precondition is not satisfied, an accurate value can not be obtained, and there is room for improvement.

In addition, Non-Patent Document 1 shows a method of obtaining the enlargement ratio by a geometric method (Equation 2.6). However, since the distance b ₀ from the X-ray source to the X-ray detector needs to be known, and the calculation formula is somewhat complicated, there is room for improvement.

Patent publication 2013-255700 gazette

Takefumi Akira, Doctoral Thesis, Graduate School of Engineering, The University of Tokyo (2014)

  According to the present invention, when the position of a radiation source such as X-ray and the relationship between the position of a receiver and an object to be inspected are unknown, the size of the object to be inspected, the radiation source, etc. An object of the present invention is to provide a fluoroscopic nondestructive inspection method and a fluoroscopic nondestructive inspection device capable of estimating the positional relationship (distance) of the body.

  The present invention acquires two or more of fluoroscopic images at each position by changing the positional relationship between the radiation source and the irradiated object, and changes the size or diameter of the image on the image, and the position Using at least one of measurement data and distance data between two positions of the radiation source and the receiver, the size of the inspection object, the magnification of the image, and the radiation source and the inspection object And providing at least one of the distances according to the geometric shape.

The present invention also relates to the positional relationship between the radiation source and the irradiated object when acquiring two or more fluoroscopic images in which the positional relationship between the radiation source and the irradiated object is changed. (F) The size of the object under inspection, the magnification of the image, and the radiation source and the object under inspection based on simultaneous equations established according to each means, changing by any of the six means shown in (f) The present invention provides a fluoroscopic nondestructive inspection method characterized by geometrically calculating and estimating at least any one of the distances
(A) means for moving the radiation source along an axis parallel to the irradiation axis of the radiation from the radiation source;
(B) a means for moving the irradiated object along an axis parallel to the irradiation axis of the radiation from the radiation source (c) an inner diameter of the surface perpendicular to the irradiation axis of the radiation from the radiation source Means for moving the irradiated object along any one axis of the direction (d) moving the radiation source along any one axis in the surface radial direction perpendicular to the irradiation axis of the radiation from the radiation source (E) at least one of the radiation source and the irradiator along two axial directions of an axis parallel to the irradiation axis of the radiation from the radiation source and any one axis in a direction radially inward of the surface Means for moving the radiation sources independently of each other, and (f) a surface formed by an axis parallel to and perpendicular to the irradiation axis of the radiation from the radiation source. Move in an in-plane direction It means for.

According to the present invention, the size (d) of an object to be inspected and the magnification ratio (D / d) of an image to be inspected, which are contained in the inside of the object to be irradiated with ionizing radiation, A fluoroscopic nondestructive inspection device for estimating at least one of the distance (a) to the body, comprising:
A radiation source for irradiating the ionizing radiation;
An image receiver for projecting an image surface of the inspection object;
The positional relationship of the irradiated body with respect to the image plane is at least one direction of an axial direction parallel to and perpendicular to the irradiation axis of the radiation from the radiation source. Or at least one of the radiation source and the receiver manually or separately in order to independently change in the in-plane oblique direction of the plane formed by the parallel axis and any one axis of the surface radial direction perpendicular to the parallel axis. A moving mechanism for moving automatically,
A sample holder for supporting the object, having a moving mechanism disposed between the image plane and the radiation source and disposed at a constant distance from the image plane;
The following (A) and (B),
(A) At least one of the radiation source and the irradiated body, at least one of an axial direction parallel to the irradiation axis of the radiation from the radiation source and an arbitrary radial direction of the surface radial direction The parallel axial direction and / or the parallel direction when moving independently in the in-plane oblique direction of a plane formed by one direction or the parallel axis and any one axis of the surface radial direction perpendicular to the plane; The size of the image of the inspection object to be displayed on the image receiving device according to the movement distance of any one axial direction in the surface inner diameter direction which is vertically positioned, and the distance (b) between the radiation source and the image plane Means for measuring and calculating the diameter or diameter (D), respectively
(B) The image of the subject to be inspected which is displayed on the image receiver with the distance (b) between the radiation source and the image surface fixed is moved in any one axial direction of the surface inner diameter direction which is positioned vertically. In the case, means for measuring and calculating the movement distance of the inspection object image, the size (d) of the inspection object, the enlargement ratio (D / d) of the image, and the radiation source and the inspection object An imaging control apparatus comprising arithmetic processing means for calculating and obtaining at least one of the positional relationship (a).

  According to the present invention, in the fluoroscopic nondestructive inspection device, the radiation source movement mechanism further includes a radiation source movement control device for automatically controlling at least one of the distance, direction, and angle of radiation source movement. There is provided a fluoroscopic nondestructive inspection apparatus characterized by

  In the fluoroscopic nondestructive inspection apparatus of the present invention, the radiation source further comprises two or more radiation sources, and the two or more radiation sources are positioned parallel to and perpendicular to the image plane. Providing a radioscopic nondestructive inspection apparatus characterized by being disposed apart by a distance corresponding to each of the moving distances when moving independently in at least any one direction in any one axial direction in the inner surface direction of the .

  The present invention is based on simultaneous equations established when measurement is performed by any of the six means shown in the (a) to (f) in the arithmetic processing means of the fluoroscopic nondestructive inspection device, There is provided a fluoroscopic nondestructive inspection apparatus characterized by determining at least one of the size of the inspection object, the magnification of the image, and the distance between the radiation source and the inspection object.

  X-ray (ionizing radiation) source or irradiated object, at least any one direction in any one axial direction in an axial direction parallel to and perpendicular to the irradiation axis of radiation from the radiation source, or The image is captured and acquired only when performing simple linear movement independently in the in-plane oblique direction of the plane formed by the parallel axis and an arbitrary one axis of the plane in the inner surface direction perpendicular to the plane. It is possible to estimate the size of an object under test (for example, rebar in concrete, human bone) which can not be measured directly. At that time, since the assistance of other nondestructive inspection methods is not required, not only the measurement is simple as compared with the conventional method, but also it is possible to significantly improve the measurement accuracy.

  In addition, since the purpose can be achieved by at least two imagings, measurement can be performed at low cost compared to X-ray CT and the like.

  Furthermore, by performing imaging three or more times, the positional relationship between the X-ray source (focus), the inspection object, and the imaging surface can be grasped. Therefore, it is not necessary to measure the positional relationship by another method.

It is a schematic diagram which shows the example of the 1st method of this invention. It is a schematic diagram which shows the modification of the 1st method of this invention. In the second method of the present invention, it is a schematic view showing an arbitrary one axis in the surface inner diameter direction which is positioned perpendicular to the irradiation axis of radiation. It is a schematic diagram which shows the example of the 2nd method of this invention. It is a schematic diagram which shows the modification of the 2nd method of this invention. It is a schematic diagram which shows the example of the 3rd method of this invention. FIG. 6 is a block diagram illustrating an example of the functionality and operation of a representative apparatus for practicing the present invention. FIG. 6 is a block diagram illustrating a variation of the functionality and operation of a representative apparatus for practicing the present invention. It is a schematic diagram which shows the Example of this invention which used the line sensor. It is a schematic diagram which showed the problem of the magnifying power in the conventional X-ray fluoroscopic imaging. FIG. 10 is a schematic view showing another problem of the magnifying power in the conventional X-ray fluoroscopic imaging, in which test objects of different sizes produce images of the same size.

  An embodiment of the invention will be described.

  In the present invention, the positional relationship between the radiation source (focus) and the irradiated object is changed to perform imaging a plurality of times, and the correlation between the position and the size of the image relative to the positional relationship between the radiation source (focus) and the irradiated object , The magnification of the image or the size of the inspection object or the position in the radiation irradiation axis direction.

  At this time, the following three methods can basically be considered as a method of changing the positional relationship between the radiation source (focus) and the irradiated object.

  The first method is a method of changing the positional relationship between the radiation source and the object along an axis parallel to the irradiation axis of the radiation from the radiation source. The second method is a method of changing the positional relationship between the radiation source and the object along any one axis in the in-plane radial direction perpendicular to the irradiation axis of the radiation from the radiation source. Then, in the third method, the radiation source is formed in an in-plane oblique direction of a plane formed by an axis parallel to and perpendicular to the irradiation axis of the radiation from the radiation source and an arbitrary uniaxial axis in the surface radial direction. A method of changing the positional relationship between the radiation source and the irradiated object. Here, the irradiation axis of radiation means, as described above, a line connecting the radiation source and the center of the irradiation field, or the apex (the focal point of the irradiation source) and the image receiving surface in the cone-like utilization line cone. It means a line connecting the center of the bottom to be formed. The first, second and third methods will be described below.

<First method>
1 and 2 are schematic diagrams illustrating the first method. In the method of changing the positional relationship between the radiation source and the object along an axis parallel to the irradiation axis of the radiation from the radiation source, FIG. 1 is a method of moving the radiation source, and FIG. It is a method to move the irradiated body that the body is embedded. The method shown in FIGS. 1 and 2 is basically applicable to ionizing radiation in general, but will be described by taking X-rays as an example. For simplicity, it is assumed that the object to be inspected is on the X-ray irradiation axis including the center of the X-ray irradiation. The subject to be inspected here refers to those which can be recognized as an image by X-ray fluoroscopy, such as a high density portion inherent to a low density material or a low density portion inherent to a high density material.

As shown in FIG. 1, the focal point 1 of the X-ray source is assumed to move on the X-ray irradiation axis. F ₀ and F ₁ are positions of the focal point 1 of the X-ray source. a ₀ and a ₁ are distances from the position (F ₀ , F ₁ ) of the focal point 1 of the X-ray source to the subject 2 and are unknown. b ₀ , b ₁ are the distances from the X-ray source to the image receiving surface 3 of the receiver. d is the size of the subject, and D ₀ and D ₁ are the sizes of the image produced by the subject at the receiver. The subscripts for each variable indicate when the position of the x-ray source is at the location corresponding to that digit.

When the focal point 1 of the X-ray source is at the position of F ₀ , the distance between the focal point 1 of the X-ray source and the inspection object 2 is a ₀ , and from the position of the focal point 1 of the X-ray source to the image receiving surface 3 The distance is b ₀ . The size of the image on the image receiving surface is D _0.

When the focal point 1 of the X-ray source is at the position of F ₁ , the distance between the focal point 1 of the X-ray source and the inspection object 2 is a ₁ , and from the position of the focal point 1 of the X-ray source to the image receiving surface 3 The distance is b ₁ . And, the size of the image on the image receiving surface is D _1.

Here, the distance when moving the X-ray source from F ₀ to F ₁ is L ₁ . For convenience, an X axis parallel to the radiation irradiation axis is defined. L ₁ at this time is a positive value if a ₀ <a ₁ . That is, the X axis is positive in the direction away from the object to be irradiated. This is a matter of definition, to define the direction away L axis from the irradiated body as a negative, a _0> L ₁ may be set as a negative value when a _1.

The method shown in FIG. 1 is expressed by the equations (1) and (2) as follows.

この関係を用いると、（１）式及び（２）式は、以下のような連立方程式となる。

この連立方程式は、ａ_０を消去してｄについて解くことが出来、

或いは、ｄを消去してａ_０について解き、

となる。 Here, a ₀ and a ₁ have the following relationship.

Using this relationship, the equations (1) and (2) become simultaneous equations as follows.

This simultaneous equation can be solved for d by eliminating a ₀ ,

Or erase d and solve for a ₀ ,

It becomes.

Therefore, the X-ray source is placed at the position of F ₀ and imaged, and then the X-ray source is moved to the position of F ₁ and imaged, and the obtained image sizes D ₀ and D ₁ Substituting the moving distance L ₁ of the focal point) and the distances b ₀ and b ₁ between the X-ray source and the image receiving surface into the above equation, the size d of the object to be inspected can be obtained. There is no need to know a ₀ and a _{1 in} advance.

If only the focal point 1 of the X-ray source is moved and the distance between the object to be inspected and the image receiving surface does not change, b ₁ = b ₀ + L ₁ can also be set. That is, in place of the equation (4), d and a ₀ can be obtained only by the movement distance L ₁ of the X-ray source by the following equation (7).

  Alternatively, it can be realized by using an apparatus integrally provided with the focal point 1 of the X-ray source and the image receiver having the image receiving surface 3 and moving the apparatus along the X-ray irradiation axis with respect to the object.

この（８）式に、ｂ_０、Ｄ_０、ｄの値を代入してａ_０の値を求めることが出来る。ａ_０からｄを求めることも然りである。 If d can be estimated, the distance a ₀ from the position F ₀ of the X-ray source to the subject can be expressed by the following equation (8) by modifying the equation (1).

The value of a ₀ can be obtained by substituting the values of b ₀ , D ₀ , and d into the equation (8). Versa to determine the d from a _0.

  Although the number of times of imaging was two, the imaging can be performed three or more times (three or more X-ray source positions).

When the position of the X-ray source (focus) is three or more, the number of equations constituting the simultaneous equations is also three or more. As one of the effects in this case, when only the X-ray source is moved, b _i is represented by L _i and b ₀ , so b _i may be erased as in the above equation (7). It can. Therefore, it is not necessary to separately measure or define the distance b _i between the X-ray source and the image receiving surface. This applies to the case of moving only the test object described later.

の様な連立方程式を得ることが出来、ｄ、ａ_０、ｂ_０の其々について、

と解ける。 When changing the position of the focal point only of the X-ray source, the change amounts L ₁ and L ₂ of the position of the focal point 1 of the X-ray source are used to a ₁ = a ₀ + L ₁ , a ₂ = a ₀ + L ₂ and b It can be placed as ₁ = b ₀ + L ₁ , b ₂ = b ₀ + L ₂ . Therefore,

The following simultaneous equations can be obtained, and for each of d, a ₀ , b ₀ ,

It can be solved.

  Next, a generalized case of changing the position of only the focal point of the X-ray source will be described.

と表すことが出来る。但し、ａ_ｉ＝ａ_０＋Ｌ_ｉ 又はａ_ｉ＝ａ_ｉ−１＋Ｌ_ｉとなる。通常Ｌ_０＝０であるが、任意の値でも良い。 In that case, for the position F _i (i = 0, 1... M) of the X-ray source (focus)

It can be expressed as _However, the a _{i =} a 0 + _{L i} or _{a i = a i-1 +} L i. Usually, L ₀ = 0, but it may be an arbitrary value.

The sign of L _i changes depending on whether the direction of movement of the X-ray source is to the receiver side or vice versa. As shown in FIG. 1, in the latter case, a _i = a ₀ + L _i or a _i = a _{i -1} + L _i , and in the former case a _i = a ₀ -L _i or a _i = a _{i -1} -L _i .

Also, for b _i , L _i is used, and in the latter case b _i = b ₀ + L _i or b _i = b _i-1 + L _i and in the former case b _i = b ₀ −L _{It can be i} or b _i = b _i-1 -L _i .

Furthermore, it is also conceivable to make b _i not a value dependent on L _i , as in the case of using a device integrally comprising the focal spot of the X-ray source and the receiver.

  Another effect when the position of the X-ray source is three or more is to evaluate an error. If the number of equations is large relative to the degrees of freedom, the simultaneous equations do not have a solution, but the equations of the simultaneous equations are estimated using the unknowns estimation method (fitting) such as the least squares method. And it becomes possible to evaluate the error.

It is accompanied by movement of the moving or the object to be inspected of the X-ray source only only, if the position of the X-ray source or four places, after erasing the b _0, it is possible to evaluate the estimation and error of d.

Although the above equation (15) is a discrete equation taking into consideration the actual measurement, it may be treated as a continuous functional equation. In that case, the subscript letter i in the above equation is removed, and a and b are represented by functions of L. In this way, the relationship between L and D can be plotted on a graph, and the equation can be fitted to the equation to obtain the unknown d and its error. As mentioned above, the focal point F ₀ of the X-ray source does not have to be at the origin. When setting a certain predetermined position as the origin, the position of F ₀ may be expressed by coordinates (X ₀ ) from the origin. In general, it is preferable to set L ₀ = 0 as the origin.

When changing the position of only the X-ray source on the coordinate axis, in the X-axis coordinate system shown in the lower part of FIG. 1, the first positions (a ₀ ′, b ₀ ′) of the irradiation source and the image receiving surface are each a ₀ ′ = a _X 1 + _{a 0} and _{b0 '= X 1 + b 0} . On the other hand, since D _i is calculated from the initial position of the irradiation source and the difference between the position of the irradiation source after moving from the initial position, the above equation (15) is expressed by a continuous equation by a function of L It can be obtained using the following equation (16) in the same manner as in the case. Each of b (L) and a (L) shown in the following equation (16) is a function with L as a variable.

On the other hand, it is also conceivable to perform one of two imagings from the opposite side of the irradiation object. Intuitively, if the subject is positioned on either side of the illumination axis, the magnification changes in response to the offset position. At first glance, although it looks like a method different from the present invention, it can be understood that it can be treated equivalently to the present invention by the way of defining L ₁ and b ₁ .

That is, F ₁ may be positioned on the opposite side of the object with respect to F ₀ . In that case, the positional relationship becomes opposite to that shown in FIG. 1, and the relationship between a ₁ and L ₁ becomes a ₁ = −a ₀ + L _1. Therefore, the equation for obtaining D ₁ is the above (4) Unlike the formula, D ₁ = db ₁ / (L ₁ −a ₀ ).

  There are several ways to change the position of the X-ray source, the position of the irradiated object, and the position of the image receiver in any relation.

For example, as shown in FIG. 2, the method of moving the to-be-irradiated body which has the to-be-tested object 2 in it can be employ | adopted. In the method shown in FIG. 2, the equations for obtaining D and a ₀ are different from those in FIG. 1 as follows.

この連立方程式を解くと、ｄ及びａ_０をそれぞれ下記の（１９）式及び（２０）式から求めることができる。

As shown in FIG. 2, for example, assuming that the movement of the irradiated object having the object under test 2 is moved once from the initial position toward the image receiver by M ₁ , the following equations (17) and (18) A simultaneous equation consisting of equations is given.

If this simultaneous equation is solved, d and a ₀ can be determined from the following equations (19) and (20), respectively.

Thus, by installing the X-ray source and captured in position F _o of focus 1 of the X-ray source, is moved by M1 to receiver side irradiated body from Fo position by imaging, the size D of the image obtained at that time _By substituting ₀ and D ₁ , the movement distance M ₁ of the inspection object 2 contained in the non-irradiated body, and the fixed distance b ₀ between the focal point 1 of the X-ray source and the image receiving surface 3 into the above equation since it is possible to calculate the size d of the test subject, it is not necessary to know in advance a ₀ and a _1. As described above, d and a ₀ can be obtained only by the movement distance M ₁ of the inspection object 1 included in the irradiation object.

と表すことが出来る。但し、ａ_ｉ＝ａ_０＋Ｍ_ｉ 又はａ_ｉ＝ａ_ｉ−１＋Ｍ_ｉとなる。通常Ｌ_０＝０であるが、任意の値でも良い。 Although the number of times of imaging described above is two, measurement can be performed even if imaging is performed three or more times (the movement of the position of the object to be irradiated is three or more). In the generalized case of changing the position of the irradiated object alone, the position Mi (i = 0, 1..., N) of the irradiated object 2 inherent to the irradiated object

It can be expressed as _However, the a _{i =} a 0 + _{M i} or _{a i = a i-1 +} M i. Usually, L ₀ = 0, but it may be an arbitrary value.

Thus, when the position of the object to be irradiated is three or more, the number of equations constituting the simultaneous equations is three or more, including the equation (17). The sign of M _i changes depending on whether the direction of movement of the object to be illuminated is in the direction of the receiver or vice versa. As shown in FIG. 2, in the former case, a _i = a ₀ + M _i or a _i = a _i-1 + M _i , and in the latter case a _i = a ₀ −M _i or a _i = a _i It can be expressed as ₋₁ −M _i .

Also in the method shown in FIG. 2, as in the method shown in FIG. 1, each position of the focal point F ₀ of the X-ray source, the irradiated object and the image receiving surface is represented by a coordinate system in which a predetermined place is set as the origin D and a ₀ may be determined using the following equation (22), which is a function of the movement amount M of the position 2 of the test object included in the irradiated object.

  There are several methods for changing the position of the X-ray source, the position of the irradiated object, and the position of the image receiver, including the above-mentioned methods, which are collectively shown below.

  One is a method of moving the X-ray source and not moving the irradiated object and the receiver as shown in FIG.

  One is a method of moving the X-ray source while maintaining the positional relationship between the irradiation object and the image receiver without moving the X-ray source.

  One is a method of moving the object without relatively changing the positional relationship and the position of the X-ray source and the receiver as shown in FIG.

  One is a method of moving the position while maintaining the positional relationship between the X-ray source and the image receiver, but not moving the irradiated object.

  One method is to change the positions of the X-ray source, the image receiver, and the irradiated object.

  In any case, it is essential to change the positional relationship between the X-ray source and the irradiated object. However, in the case where all positions of the X-ray source, the receiver and the irradiated object are changed as described above, estimation of unknowns with multiple variables of two or more variables is performed. Therefore, it is desirable not to change the positional relationship between the X-ray source and the receiver or the positional relationship between the irradiated object and the receiver.

<Second method>
The second method of changing the positional relationship between the X-ray source and the object to be irradiated along an arbitrary one axis in the surface radial direction perpendicular to the irradiation axis of the radiation from the radiation source will be described. In the present invention, any one axis in the surface radial direction perpendicular to the irradiation axis of the radiation from the radiation source is perpendicular to the irradiation axis 4 of the radiation from the radiation source, as shown in FIG. In the surface 5 located, it means any one of the axes represented by the radially extended arrows (→). As an axis represented by an arrow (→), an arbitrary direction can be basically selected at an angle of 360 degrees on the surface 5. Here, in order to simplify the description, the case of changing the positional relationship between the X-ray source and the irradiated object along the axis 6 in the vertical direction (vertical direction in the figure) of the surface 5 will be described using FIGS. explain.

  FIGS. 4 and 5 are schematic diagrams for explaining the second method, FIG. 4 shows a method of moving the irradiated object including the inspection object 2, and FIG. 5 is a method of moving the radiation source (focus) 1 It is. The methods shown in FIGS. 4 and 5 are basically applicable to ionizing radiation in general, but will be described by taking X-rays as an example.

Ｈ_１は被照査体２を放射線の照射軸４に対して垂直方向に移動させる距離そのものである。この関係を逆手に取り、ａ_０を求めることが出来る。すなわち、ｂ_０が既知であるとすれば、

として、ａ_０を求めることが出来る。 4, when there is a subject 2 inherent to the irradiated body to the position of A _0, the position of the image receiving surface 3 of the image is A _{0 '.} Next, when the at position A ₁ is moved from A ₀ by H ₁ in the direction perpendicular to the irradiation axis of X-rays to the subject 2, the position of the image and A _{1 '.} The image of the subject 2 imaged at the position of A ₁ ′ moves by H ₁ ′ from the X-ray irradiation axis. Further, the distance the distance from the X-ray focal point _{F 0} to the subject 2 from the position _{F 0} of the focus 1 of _a 0, X-ray to the image-receiving surface 3 and _{b 0.} The distance H ₁ ′ between A ₀ ′ and A ₁ ′ is expressed by the following equation (23).

H ₁ is the distance itself for moving the object 2 in the direction perpendicular to the radiation axis 4 of radiation. This relationship can be reversed to determine a ₀ . That is, if b ₀ is known,

As, a ₀ can be determined.

のように求めることが出来る。 If a ₀ can be obtained, then the size of the image of the inspection object 2 on the image receiving surface 3 at the position of A ₀ ′ is D ₀ , and the size d of the inspection object is Can be represented.

It can be asked like

Although H ₁ ′ is shown in FIG. 4 as the distance between the central portions of the images captured at the positions of A ₀ ′ and A ₁ ′, the present invention is not limited to the distance between the centers of the images, The edge of the image may be selected as the measurement point of H ₁ '. In addition, it is possible to select two or more points of the center and a predetermined point other than the center to measure H ₁ ′. The point is that it is necessary to select and measure one or more sharp points in the image to be captured so that the movement distance H ₁ ′ can be accurately measured.

In FIG. 4, A ₀ ′ is drawn to lie on the irradiation axis, but it does not require that A ₀ ′ be on the irradiation axis in practice. However, when the image receiving surface is flat, it is known that the image is distorted as it goes away from the center of the irradiation, so either correct this distortion or pick up an image at a position as close to the center of the irradiation field as possible. It is desirable to measure.

Also, if the positions of A ₀ ′ and A ₁ ′ can be determined, the relationship between the focal point 1 of the X-ray source and the image receiving surface position 3 of the receiver does not have to be the same between the two imagings. For example, when the irradiated object is moved H _1, the image receptor may also be moved H ₁ in the same direction. Moving distance _{H 1} of the image on the receiver when the irradiated object and image receptor has moved _{H 1} "is 'to become _{-H 1, H 1' H 1} = H 1" + readily obtained as of an _{H 1} I can do it. Even if the receiver is moved by an arbitrary distance, H ₁ can be obtained from the movement distance. If the receiver is capable of acquiring and displaying an image online, if the receiver is moved so that the image is at the center of the receiver at position A ₀ and position A ₁ , the moving distance is H ₁ It corresponds to '.

However, in the case of rebar or the like which is an inspection object disposed horizontally inside the reinforced concrete which is the irradiation object, it is possible to identify that the position of the image has changed even if the X-ray source or the irradiation object is moved horizontally. Absent. Therefore, it is necessary to move the X-ray source or the object in the vertical direction in order to know the magnifying power of the horizontally disposed reinforcing bars. That is, it is necessary to move in a direction (perpendicular as much as possible) which is not horizontal to the direction of arrangement of rebars or the like. The X-ray source or the object is moved along an axis which is not perpendicular (as far as possible) to the straight line connecting the two points of the contour to be measured of the object to be measured. On the other hand, in the case of reinforcing bars arranged vertically, they are moved horizontally. Therefore, when reinforcing bars are arranged in the vertical and horizontal directions (generally orthogonal), a method of imaging by moving it in the horizontal direction and in the vertical direction can be considered, but at least three imagings are required. In order to complete imaging twice, it is preferable to move in a diagonal direction which is neither horizontal nor vertical, so that the positional relationship between the horizontal direction and the vertical direction changes simultaneously.

  In the second method, as in the first method, three or more movements and imaging may be performed in one direction.

のように、複数のＨ_ｊとＨ_ｊ’についての連立方程式をたて、第一の方法と同様に、最小二乗法等の未知数推定法(フィッティング) を用いてａ_０を推定する。ａ_０が推定できれば、ｄも評価可能となる。 Specifically, the above equation (23) is generalized, and each position A _j (j = 0, 1,..., S) after the position 2 of the inspection object contained in the irradiated object is changed by its movement. For)

As in the above, simultaneous equations for a plurality of H _j and H _j ′ are prepared, and a ₀ is estimated using an unknown number estimation method (fitting) such as the least squares method as in the first method. If a ₀ can be estimated, d can also be evaluated.

Even if a ₀ and b ₀ are unknown, it is possible to estimate a ₀ and b ₀ by evaluating with three or more points of H _j based on the equation (26). Or, the evaluation of d becomes possible by the equation (26).

When d is calculated using the equation (26), generalization is possible as in the following equation (27), and in the same way, to estimate a ₀ , b ₀ and d with three or more H _j Can.

  With regard to how to change the position of the X-ray source, the position of the irradiated object, and the position of the image receiver, as in the first method, there are several methods other than the method of moving only the irradiated object. There is a method of

For example, as shown in FIG. 5, by moving the radiation source, a method of moving its focal point _Fo in the vertical direction can be employed. The method shown in FIG. 5 is as follows when the equations for obtaining D and a ₀ are different from those in FIG.

Although FIG. 5 is an example of moving the radiation source from the first position, if it is assumed that moving once only G ₁ downward along the axis 6 shown in FIG. 5, the image of the subject 2 measured after movement The center position moves upward on the image receiving surface 3 by G ₁ ′. Here, assuming that the distance from the X-ray focal point F ₀ to the inspection object 2 is a ₀ and the distance from the X-ray focal point F ₀ to the image receiving surface 3 is b ₀ , G ₁ ′ is expressed by the following equation (28) Ru.

The relationship of equation (28) can be reversed to obtain a ₀ . That is, if _{b 0} is known, can be obtained _{a 0} from the following equation (29).

Also in the method shown in FIG. 5, as in the method shown in FIG. 4, the radiation source can be moved twice or more and imaging of the object can be performed each time. Even if a ₀ and b ₀ are unknown, it is possible to estimate a ₀ and b ₀ by evaluating with three or more G _j based on equation (29), and equation (1) And (29) make it possible to evaluate d.

となる。 Further, Formula (29) can be generalized as shown in Formula (1) to Formula (30) below, and in the same manner, a ₀ , b ₀ and d can be estimated with three or more G _i can do. Specifically, for each position G _j (j = 0, 1,..., T) after the position of the focal point 1 of the radiation source contained in the irradiated body is changed due to its movement

It becomes.

  In the inspection method of the present invention, in the case of changing the positional relationship between the radiation source and the irradiated body when acquiring two or more fluoroscopic images in which the positional relationship between the radiation source and the irradiated body is changed, It is not limited to either of the first method and the second method. The two methods are used in combination in one measurement, and the radiation source and the radiation source are disposed along two axes in any one axis in the radial direction of the plane, which is parallel to and perpendicular to the irradiation axis of radiation from the radiation source. A method of moving at least one of the irradiators may be employed. For example, as described above, as in the case where reinforcing bars are arranged vertically and horizontally inside the concrete, the object to be inspected is scattered at a plurality of locations in a three-dimensional manner with respect to the image surface. The magnification of the image of a plurality of inspection objects by a method of acquiring an image of the inspection object each time while moving at least one of the radiation source and the irradiation object along two axes. And at least any one of the distance between the radiation source and the subject can be geometrically calculated and estimated.

  When the first method and the second method are used in combination, the moving direction and moving distance of the two axes, and the size and moving distance of the image on the image plane are stored as data for each measurement, and the data is used Detailed analysis can be performed by each equation exemplified above. This method is effective for performing the object mapping process in the object to be irradiated because the existence positions of the object to be inspected present at a plurality of locations on the object to be irradiated can be clarified.

<Third method>
The radiation source and the position of the radiation object in the in-plane oblique direction of the plane formed by an axis parallel to and perpendicular to the irradiation axis of the radiation from the radiation source in an in-plane direction of the plane A third method of changing the relationship will be described with reference to FIG. Here, a surface formed by an axis parallel to the irradiation axis of the radiation from the radiation source and an arbitrary uniaxial axis in the radial direction of the surface positioned perpendicular to the irradiation axis of the radiation source is the irradiation axis 4 of the radiation in FIG. And a radially extending axis of the surface 5 positioned perpendicular to the irradiation axis 4, for example, the surface formed by the axis 6.

  FIG. 6 is a schematic view for explaining a third method of moving the radiation source 1 obliquely in the plane, which is basically applicable to ionizing radiation in general but will be described by taking X-rays as an example.

図６においては、画像の歪みが最も小さいと考えられる画像の中心を、便宜上、Ａ_０及びＡ_０’の位置に設定している。 6, when there is a subject 2 inherent to the irradiated body to the position of A _0, the position of the image receiving surface 3 of the image is A _{0 '.} Next, move from F ₀ to F _{0 'the} radiation source 1 to the plane oblique plane formed by any single plane inside diameter direction located in an axis parallel and perpendicular to the irradiation axis of the X-ray . In this case, parallel movement distance and the irradiation axis of X-rays is a _1, the vertical movement distance and I _1. The distance the distance from the focal point F ₀ of the X-ray irradiation source 1 to the subject 2 from a _0, the focal point F ₀ of the X-ray irradiation source 1 to the image receiving surface 3, b _0. Then, assuming that the image of the inspection object 2 obtained after moving the irradiation source 1 obliquely is at the point of Ao ′ after moving at a distance I ₁ ′ upward from the position of A ₀ , the following (31 Equation (32) is established.

In FIG. 6, the center of the image which is considered to have the least distortion of the image is set at the positions of A ₀ and A ₀ ′ for the sake of convenience.

Further, the following equation (33) is established between I ₁ and I ₁ ′.

Therefore, a ₀ and d can be determined from the following equations (34) and (35), respectively.

  In the third method, as in the first and second methods, three or more movements and imaging may be performed in one direction.

のように、複数のＩ_ｋとＩ_ｋ’についての連立方程式をたて、第一及び第二の方法と同様に、最小二乗法等の未知数推定法(フィッティング) を用いてａ_０を推定する。ａ_０が推定できれば、ｄも評価可能となる。 Specifically, the above equation (33) is generalized, and for each position I _k (k = 0, 1,..., P) after the position of the focal point 1 of the radiation source is changed by its movement

As in the above, set simultaneous equations for a plurality of I _k and I _k 'and estimate a ₀ using an unknown number estimation method (fitting) such as the least squares method as in the first and second methods. . If a ₀ can be estimated, d can also be evaluated.

Even if a ₀ and b ₀ are unknown, it is possible to estimate a ₀ and b ₀ and d by evaluating with three or more I _k based on the following equation (37).

  The present invention acquires two or more of fluoroscopic images at each position on the image plane 3 by changing the positional relationship between the radiation source 1 and the irradiated object including the inspection object 2, and the image on the image The basic idea is to conduct analysis using measured data of at least one of the size or the diameter and the change of the position, and the distance data between two positions of the radiation source and the receiver. Therefore, the present invention is not limited to the methods described in the first, second and third methods described above, but also from the positional relationship between the radiation source 1 and the irradiated object including the inspection object 2 and the image surface 3 A method capable of geometrically calculating and analyzing may be adopted. In the measurement of the image size in the present invention, a method of measuring the image size in the conventional simple imaging can be applied. Even when the irradiation axis and the image receiving surface do not intersect perpendicularly, various correction methods have been proposed, and the existing correction methods can be applied to the present invention.

<Radioscopic nondestructive inspection device>
Next, the configuration of the fluoroscopic nondestructive inspection apparatus according to the present invention will be described. FIG. 7 shows a block diagram illustrating the function and operation of a representative apparatus for implementing the first method of the present invention. The basic configuration of the second method and the third method is substantially the same except that the moving direction or moving angle of the radiation source or the irradiation target including the inspection object is different.

  The inspection apparatus shown in FIG. 7 includes a radiation source for irradiating ionizing radiation, a moving mechanism for moving the radiation source, a receiver for projecting an image surface of the object to be inspected, and a receiver for moving the receiver. , A sample holder for supporting the object to be irradiated, a moving mechanism for moving the sample holder, and an imaging control device having arithmetic processing means for controlling them in an integrated manner. Here, the movement mechanism of the radiation source, the movement of the sample holder and the receiver are performed manually or automatically, but the direction and distance are automatically controlled independently by the movement mechanism drive unit electrically connected to the respective mechanisms. It is practical to do. In addition, since the moving mechanism for moving the image receiver is driven to relatively change the positional relationship between the image receiver and the radiation source (or the object to be inspected), one of the two has an installation position. You may use it in the fixed state without changing.

  The imaging control apparatus shown in FIG. 7 has the following (A) and (B), that is, (A) at least one of the radiation source and the irradiation object with respect to the radiation axis of the radiation from the radiation source. A surface formed by at least one of any parallel axis directions and any one axial direction in the radial direction of the surface radially located in the vertical direction or the parallel axis and any one axis in the radial direction of the surface positioned in the vertical direction The distance of movement between the radiation source and the image plane along the parallel axial direction and / or the direction of any one axial direction in the radial direction of the surface located in the vertical direction when moving independently in the in-plane oblique direction independently. (B) means for measuring and calculating the size or diameter (D) of the inspection object image to be displayed on the image receiver according to (b), and (B) the distance between the radiation source and the image plane ( Displayed on the receiver with constant b) When the inspection object image moves in any one axis direction of the surface inner diameter direction where the inspection object is positioned vertically, the inspection object image includes means for measuring and calculating the movement distance of the inspection object image, and the arithmetic processing unit At least one of the size (d) of the object to be inspected, the enlargement ratio (D / d) of the image, and the positional relationship (a) between the radiation source and the object to be inspected is calculated.

  The imaging control apparatus is basically a computer, and also performs image processing such as calculation after image acquisition. The computer may be a general computer provided with a display (image display device) and a human interface (keyboard, pointing device such as mouse, touch panel, etc.). FIG. 7 shows by way of example a device for carrying out the method of performing only the movement of the focal point of the radiation source, but the combination of the movement of the focal point of the radiation source, the object and the receiver is also basic. The way of thinking is similar.

The imaging control device instructs the moving mechanism driving device of the radiation source, drives the moving mechanism of the radiation source to move the focal point of the radiation source such as X-ray to the position of F ₀ , and performs imaging. If the receiver is an FPD or the like, the acquired image is sent directly to the imaging control device for storage. In the case of an X-ray film or an imaging plate, the cassette is taken out by hand and the image is read by a scanner and stored in an imaging control device. Depending on the type of X-ray film, development is necessary.

  Although it is normal for the inspector (operator of the device) to give instructions for irradiation each time radiation is applied, the imaging control device automatically issues an irradiation instruction to the radiation source to perform radiation irradiation. There is also.

Next, the focal point of the radiation is moved to the position of F ₁ and imaging is performed.

  Although the order of the above imaging is arbitrary, it is necessary to record which image is captured at which focal position. There are several methods, but there is a method of storing the image in a predetermined file or memory area. It is also conceivable to embed focus information or the value of the movement distance (L) in the image data itself. Furthermore, there is also a method of recording the file or memory area of the acquired image data and the focal position or L in a table. These are problems of computer data handling and are not essential problems in the present invention.

The size or diameter (D _o and D ₁ ) of the image is then measured from the acquired image. Specifically, each of the acquired images at the focal position (F ₀ and F ₁ ) of the radiation source is alternately or simultaneously displayed on the display, and the examiner is given a portion or range to be measured by a cursor or the like. In many cases, a line segment is drawn by the cursor from the edge to the edge of the image, and the length of the line segment on the image may be used as a measurement value. It is also technically possible to extract contours automatically from a given measurement range.

If D _o and D ₁ can be measured, the focal distance L and a predetermined value, the distance from the focal point of the radiation source to the image receiving surface (b ₀ ), are used using Eqs. (5) and (6) Calculate the size or diameter (d) of the test subject or the distance (a ₀ ) between the focus of the radiation source and the test subject, store it in a memory or file, or display it as an image (text information etc.) on the display Do.

FIG. 8 shows a modification of a block diagram showing the function and operation of a representative apparatus for implementing the first method of the present invention. The portion different from FIG. 7, the association with each acquired image information L, when performing arithmetic processing, is to create a table indicating the association of L _i and Di. Thus, even in the case where the number of measurement points is three or more (three acquired images), d or a ₀ can be estimated using an unknown number estimation method (fitting) such as the least squares method. Of course, this example works even if there are two measurement points. In the case the measurement points is 3 points b ₀ can be applied if it is unknown.

  EXAMPLES Hereinafter, examples based on the present invention will be specifically described, but the present invention is not limited by these examples.

Example 1
As a method of practicing the present invention, as shown in FIG. 1, a method of simply moving a radiation generator or the like (X-ray source) manually can be considered. Conversely, as shown in FIG. 2, the side of the object to be irradiated (inspection object) may be moved. The inventor gives the distance L ₁ or M ₁ between the X-ray source and the inspection object by manually moving the object and the X-ray inspection detector on the loading platform during the verification test of the present invention. ₁ or M ₁ was measured with a tape measure. The evaluation of d can be performed by hand calculation or a calculator, and it is also possible to input the measurement value into the spreadsheet software at the inspection site and evaluate d by previously inputting the formula into the spreadsheet software.

(Example 2)
When the irradiated body is large, the movement of the irradiated body is difficult. Therefore, moving the x-ray source becomes practical. It is also conceivable to move the X-ray source manually as in the first embodiment.
Place the radiation source on the X-ray source moving mechanism. The X-ray source movement mechanism is placed on a manual linear movement stage or an automatic linear movement stage. The X-ray source moving mechanism can be controlled by an imaging control device (computer) to automatically position the X-ray source, and an image can be acquired each time. If the image acquisition is performed electronically as with FPD, the calculation of d can be automated by correlating each image with the position of the X-ray source by a computer.

(Example 3)
In medical X-ray apparatuses, X-ray films and imaging plates are often used as image receivers. The use of FPD is also beginning. Although the X-ray film and the imaging plate are used in a cassette, the installation position of the cassette is often roughly determined, such as the upper surface of the bed. In the X-ray apparatus, an X-ray tube is used as an X-ray source, and an X-ray head incorporating an X-ray tube at the free arm tip is provided, so that the X-ray irradiation position and direction can be manually set freely. ing. If an angle sensor or the like is provided at the joint of the arm or a linear scale is provided at the telescopic portion, the position and the irradiation direction of the X-ray head moved manually can be calculated. If the position of the X-ray head and the irradiation direction are known, the present invention can be applied on the assumption that the position of the cassette does not change substantially. For example, in the case of a patient on a bed, the height of the cassette is constant for any imaging and is installed horizontally. If the height of the X-ray head is known, then b ₀ can be defined. Also in the case of horizontal irradiation, there is a table on which a cassette is set, and the patient is positioned there to perform imaging, so that b ₀ can be similarly defined.

  It is possible that the image used for diagnosis (the diagnostic image) and the image used for calculation of the magnification ratio (magnification ratio calculation image) do not have to have the same linear brightness, so the diagnostic image is captured at a normal dose. Furthermore, a method of imaging an image for calculating the enlargement ratio at a low dose is also conceivable, which can suppress the exposure of the patient.

  Of course, it is also conceivable to apply other methods to know the position of the X-ray source and the X-ray irradiation direction. Methods such as using a laser three-dimensional position measuring device or ultrasonic distance measuring device, or indexing multiple X-ray sources with a built-in X-ray source (focus) from the camera image by installing multiple cameras on the wall Conceivable.

  In the case of moving the X-ray head manually, the portion of the X-ray source moving mechanism shown in FIG. 7 or 8 corresponds to an arm, and position information is determined by the above method and sent to the imaging control device.

  When performing two imagings, the position of the X-ray tube built in the X-ray head is moved without moving the X-ray head at the second imaging, and the X-ray source (focus) is It is also conceivable to change the position. That is, the X-ray head is equipped with the X-ray source moving mechanism and the X-ray tube.

  If an FPD or other electronic image acquisition device is used as the image receiver, the position of the X-ray source is associated with the captured image, and the association information is used to estimate the size d of the subject You can do it.

(Example 4)
In imaging using so-called microfocus X-ray sources, products with high magnification can also be seen. However, the fact that the magnification is high also means that the distance between the X-ray source and the subject is very small. In such a case, the enlargement ratio may change significantly with a slight change in the position of the subject. Positioning of the subject to define the magnification is not easy, and the magnification may include large errors.

  With regard to the above-mentioned microfocus X-ray imaging, although it is conceivable to calibrate the magnification ratio using a calibration test object of a known size, the test object is placed at the same place as the calibration test object. I can imagine that is not easy.

  This problem can be solved by applying the present invention. For example, there is an X-ray examination apparatus equipped with an irradiated body moving mechanism capable of precisely positioning the irradiated body. With such an apparatus, imaging is performed several times in the method according to the invention. The moving mechanism moves the irradiated object in the direction of the X-ray irradiation axis. An error in the absolute positional relationship between the X-ray source, the irradiated object, and the imaging surface depends on machining accuracy, but an error in the relative movement of the irradiated object depends on a relative positioning error of the irradiated object moving mechanism.

  Also in the so-called micro focus CT apparatus, the enlargement ratio of the reconstructed image obtained by the positional relationship between the CT reconstruction center, the X-ray source, and the imaging plane is determined. Generally, the error in the positional relationship between the CT reconstruction center, the X-ray source, and the imaging surface is determined by the machining accuracy, but as in the case of the above-described microfocus X-ray imaging, the CT reconstruction center is moved in the X-ray irradiation axis direction To obtain a plurality of CT reconstructed images, the magnification and reconstruction of the size of the inspection object at each reconstruction center position on the reconstructed image in the first method or the second method The size of the subject on the image can be estimated.

(Example 5)
As described above, the problem of magnification does not occur in the scanning direction of the line sensor, but the problem of magnification occurs in the axial direction of the sensor.

  In general, line sensors are often used for baggage inspection at airports and quarantines at ports, but X-ray sources and line sensors are fixed, and the inspection object between the X-ray sources and line sensors is a belt conveyor etc. It is made to pass by means for moving the inspection object.

Usually, there is only one set of X-ray source and line sensor, but it is also conceivable to have a plurality of X-ray sources and line sensors. Specifically, as shown in FIG. 9, a plurality of sets of X-ray tubes and line sensors are installed along a belt conveyor. In that case, L ₀ can be defined by changing and installing the distance between the X-ray source and the belt conveyor, and imaging can be performed by changing the distance between the X-ray source and the inspection object by L ₀ .

  As a matter of course, since the timing at which the subject passes the X-ray source and line sensor pair is determined by the feed speed of the belt conveyor, the image obtained by the first line sensor pair and the second line sensor pair It is desirable to correct the positional relationship by shifting the time axis of the acquired image in consideration of the feed speed of the belt conveyor and the distance between the first set and the second set in the image obtained in the above.

  In the present embodiment, three or more sets of X-ray sources and line sensors may be used.

(Example 6)
As a simple method of carrying out the second method, the X-ray film or imaging plate is once installed and imaging is performed for the first time, and the X-ray film or imaging plate is left as it is with the position of the X-ray source or irradiated object. It is a method to change, and to perform imaging for the second time in the said X-ray film or another place on an imaging plate. In other words, perform over-recording. The X-ray film needs to be developed for each imaging, and a new X-ray film is required each time. However, the time and the number of used films can be saved by performing the recording. Further, even with an imaging plate, operations such as installation, removal and reading of a cassette are required, but it is possible to save this labor by overlapping recording.

(Example 7)
In the nondestructive inspection, in addition to the X-ray generator, gamma rays emitted from radioactive materials may be used. The position of the radiation source can be easily changed by using a radiation source delivery system among the gamma irradiation devices. In this case, the transmission pipe is installed to coincide with the irradiation axis according to the first method, and the transmission pipe is installed perpendicular to the irradiation axis according to the second method. Thus, measurement can be performed using the first method and the second method in combination.

  In the medical field, the size of the affected area such as internal organs and the thickness of bone can be estimated without using CT.

  In addition, in checking the soundness of structures such as concrete, it is possible to easily quantify the soundness of the main parts such as rebar without relying on CT etc while suppressing the cost.

  In addition, the magnification factor can be accurately determined in microfocus X-ray imaging and the like. The fluoroscopic nondestructive inspection method and the fluoroscopic nondestructive inspection device of the present invention should be applied not only to the fields of medical care and construction and civil engineering but also to products and parts used in various fields as industrial and consumer applications. In addition to being simple as compared to the prior art, it is possible to improve the measurement accuracy, so its usefulness is extremely high.

1 ... focus of radiation source,
2 ... inspection body 3 ... image surface 4 ... irradiation axis of radiation 5 ... surface perpendicular to the irradiation axis 6 ... axis in the in-plane perpendicular direction

Claims (15)

From the transmission image using ionizing radiation, at least one of the size of the object to be inspected, the magnification of the image, and the positional relationship between the radiation source and the object to be inspected included in the irradiated object of the ionizing radiation is estimated Nondestructive inspection method to
By changing the positional relationship between the radiation source and the irradiation object, two or more of fluoroscopic images at respective positions are obtained, and at least one of changes in size or diameter of the image on the image and position thereof Using at least one measurement data and distance data between two positions of the radiation source and the receiver, at least the size of the inspection object, the magnification of the image, and the distance between the radiation source and the inspection object A fluoroscopic nondestructive inspection method characterized by geometrically calculating and estimating any one. The radioscopic nondestructive inspection method according to claim 1, wherein the positions of the radiation source and the irradiation subject at the time of acquiring two or more fluoroscopic images in which the positional relationship between the radiation source and the irradiation subject is changed. The relationship is changed by moving the radiation source along an axis parallel to the irradiation axis of the radiation from the radiation source,
At least one of the size of the subject, the magnification of the image, and the distance between the radiation source and the subject using one or more simultaneous equations of the following formula (1) and the following formula (2) A method of fluoroscopic nondestructive inspection characterized by geometrically calculating and estimating one.

(Wherein, a ₀ , b ₀ , and D ₀ are respectively the distance from the position of the radiation source at the initial position to the subject, the distance from the radiation source to the receiver, and the receiver I is an integer from 1 to m, D _i and L _i are each a radiation source (focus point) when the radiation source is moved m times along an axis parallel to the irradiation axis ) is a moving distance of the object to be inspected is the size of the image to make the receiver, and the first position of the radiation source to the i-th position when placed to the i-th position .L _i, the radiation It has a negative value when the source moves to the receiver side, and a positive value when the radiation source moves to the side opposite to the receiver side, where d is the size or diameter of the test subject is there.) The radioscopic nondestructive inspection method according to claim 1, wherein the positions of the radiation source and the irradiation subject at the time of acquiring two or more fluoroscopic images in which the positional relationship between the radiation source and the irradiation subject is changed. Changing the relationship by moving the object along an axis parallel to the irradiation axis of the radiation from the radiation source;
At least one of the size of the subject, the magnification of the image, and the distance between the radiation source and the subject using one or more simultaneous equations of the following formula (1) and the following formula (3) A method of fluoroscopic nondestructive inspection characterized by geometrically calculating and estimating one.

(Wherein, a ₀ , b ₀ , and D ₀ are respectively the distance from the position of the radiation source at the initial position to the subject, the distance from the radiation source to the receiver, and the receiver I is an integer from 1 to n, and D _i and M _i are the objects to be irradiated when the object is moved n times along an axis parallel to the irradiation axis. Is the size of the image the subject makes on the receiver when it is placed at the i-th position, and the moving distance from the first position of the subject to the i-th position, where M _i is the subject. When the irradiator moves toward the image receiver, it takes a positive value, and when the irradiated object moves away from the image receiver, it takes a negative value, where d is the size of the object under test. Or diameter) The radioscopic nondestructive inspection method according to claim 1, wherein the positions of the radiation source and the irradiation subject at the time of acquiring two or more fluoroscopic images in which the positional relationship between the radiation source and the irradiation subject is changed. The relationship is changed by moving the object along any one axis in the in-plane radial direction perpendicular to the irradiation axis of the radiation from the radiation source,
At least one of the size of the inspection object, the magnification of the image, and the distance between the radiation source and the inspection object, using one or more simultaneous expressions of the following expression (1) and the following expression (4) A method of fluoroscopic nondestructive inspection characterized by geometrically calculating and estimating one.

Where D ₀ , a ₀ , and b ₀ are respectively the size of the image made by the subject at the receiver at the first position, the distance from the position of the radiation source to the subject, and Where j is an integer from 1 to s, and D _j , H _j , and H _j ′ are arbitrary in-plane radial directions perpendicular to the radiation irradiation axis of the object to be irradiated The size of the image the subject under test makes on the receiver when placed at the j-th position of the illuminated object when moving s times along one axis of the subject, j-th from the first position of the illuminated object And the movement distance from the first position of the image formed on the image receiver to the j-th position, where d is the size or diameter of the test subject). The radioscopic nondestructive inspection method according to claim 1, wherein the positions of the radiation source and the irradiation subject at the time of acquiring two or more fluoroscopic images in which the positional relationship between the radiation source and the irradiation subject is changed. The relationship is changed by moving the radiation source along any one axis in an in-plane radial direction perpendicular to the irradiation axis of the radiation from the radiation source,
At least one of the size of the subject, the magnification of the image, and the distance between the radiation source and the subject using one or more simultaneous equations of the following formula (1) and the following formula (5) A method of fluoroscopic nondestructive inspection characterized by geometrically calculating and estimating one.

Where D ₀ , a ₀ , and b ₀ are respectively the size of the image made by the subject at the receiver at the first position, the distance from the position of the radiation source to the subject, and The distance to the receiver of j is an integer from 1 to t, and D _j , G _j , and G _j ′ are any in-plane radial directions perpendicular to the radiation irradiation axis of the radiation source. The size of the image that the object under test produces on the receiver when placed at the j-th position of the radiation source when moving t times along one axis, from the first position of the radiation source to the j-th position And the movement distance from the first position of the image formed on the image receiver to the j-th position, where d is the size or diameter of the test subject).   The positional relationship between the radiation source and the irradiated body when acquiring two or more fluoroscopic images in which the positional relationship between the radiation source and the irradiated body is changed is defined with respect to the irradiation axis of the radiation from the radiation source. By independently changing at least one of the radiation source and the irradiator along two axial directions of two parallel axes and an arbitrary one axis of the surface radial direction which is vertically positioned. 6. The method according to any one of claims 1 to 5, wherein at least one of the size of the inspection object, the magnification of the image, and the distance between the radiation source and the inspection object is geometrically calculated and estimated. The fluoroscopic nondestructive inspection method according to one item. The radioscopic nondestructive inspection method according to claim 1, wherein the radiation source is formed by an axis parallel to and perpendicular to an irradiation axis of radiation from the radiation source. By moving in the in-plane oblique direction, the center of the fluoroscopic image acquired at each position moves along any one axis in the surface radial direction perpendicular to the radiation irradiation axis Measurement data and distance data moving along any one axis in the surface radial direction parallel to the radiation irradiation axis and perpendicular to the radiation irradiation axis between two positions of the positional relationship between the radiation source and the image receptor And the simultaneous expression consisting of one or more of the following formula (1) and the following formula (6), the size of the inspection object, the magnification of the image, and the distance between the radiation source and the inspection object At least Radiographic non-destructive inspection method characterized by one estimated geometrically calculated or Re.

(Wherein, a ₀ , b ₀ , and D ₀ are respectively the distance from the position of the radiation source at the initial position to the subject, the distance from the radiation source to the receiver, and the receiver _K is an integer from 1 to p, and a _k , I _k and I _k ′ are the planes formed by the radiation source in an axis horizontal to and perpendicular to the irradiation axis. When the movement distance from the first position of the radiation source to the kth position is projected on an axis parallel to the radiation irradiation axis when moving p times in the in-plane diagonal direction, values from the first position of the inspection object A value obtained by projecting the movement distance to the k-th position onto the arbitrary one axis in the surface radial direction perpendicular to the radiation irradiation axis, and the k-th from the first position of the center of the image formed on the receiver The movement distance of the above-mentioned arbitrary uniaxial direction to the position of The size or diameter of.) From the transmission image using the ionizing radiation, the size (d) of the subject to be examined contained inside the irradiated body of the ionizing radiation, the magnification ratio of the image (D / d) and the distance between the radiation source and the subject A fluoroscopic nondestructive inspection device for estimating at least one of (a), comprising
A radiation source for irradiating the ionizing radiation;
An image receiver for projecting an image surface of the inspection object;
The positional relationship of the irradiated body with respect to the image plane is at least one direction of an axial direction parallel to and perpendicular to the irradiation axis of the radiation from the radiation source. Or at least one of the radiation source and the receiver manually or separately in order to independently change in the in-plane oblique direction of the plane formed by the parallel axis and any one axis of the surface radial direction perpendicular to the parallel axis. A moving mechanism for moving automatically,
A sample holder for supporting the object, having a moving mechanism disposed between the image plane and the radiation source and disposed at a constant distance from the image plane;
The following (A) and (B),
(A) At least one of the radiation source and the irradiated body, at least one of an axial direction parallel to the irradiation axis of the radiation from the radiation source and an arbitrary radial direction of the surface radial direction The parallel axial direction and / or the parallel direction when moving independently in the in-plane oblique direction of a plane formed by one direction or the parallel axis and any one axis of the surface radial direction perpendicular to the plane; The size of the image of the inspection object to be displayed on the image receiving device according to the movement distance of any one axial direction in the surface inner diameter direction which is vertically positioned, and the distance (b) between the radiation source and the image plane Means for measuring and calculating the diameter or diameter (D), respectively
(B) The image of the subject to be inspected which is displayed on the image receiver with the distance (b) between the radiation source and the image surface fixed is moved in any one axial direction of the surface inner diameter direction which is positioned vertically. In the case, means for measuring and calculating the movement distance of the inspection object image, the size (d) of the inspection object, the enlargement ratio (D / d) of the image, and the radiation source and the inspection object An imaging control device including arithmetic processing means for calculating and obtaining at least one of the positional relationship (a);
Radioscopic nondestructive inspection device having.   9. The radioscopy non-destructive according to claim 8, wherein the radiation source movement mechanism further comprises a radiation source movement control device for automatically controlling at least one of the distance, direction and angle of radiation source movement. Inspection device.   The radiation source is composed of two or more radiation sources, and the two or more radiation sources are at least one direction in any one axial direction in a plane radial direction parallel and perpendicular to the image plane. 10. The radioscopy nondestructive inspection device according to claim 8 or 9, which is disposed apart by a distance corresponding to each of the movement distances when moving independently of each other. When moving the radiation source in a direction parallel to the irradiation axis of the radiation from the radiation source in the arithmetic processing means, one or more simultaneous equations of the following equation (1) and the following equation (2) are used: At least one of the size (d) of the object to be inspected, the enlargement ratio (D / d) of the image, and the positional relationship (a) between the radiation source and the object to be inspected is determined. 11. The fluoroscopic nondestructive inspection device according to any one of Items 8 to 10.

(Wherein, a ₀ , b ₀ , and D ₀ are respectively the distance from the position of the radiation source at the initial position to the subject, the distance from the radiation source to the receiver, and the receiver I is an integer from 1 to m, D _i and L _i are each a radiation source (focus point) when the radiation source is moved m times along an axis horizontal to the irradiation axis ) is a moving distance of the object to be inspected is the size of the image to make the receiver, and the first position of the radiation source to the i-th position when placed to the i-th position .L _i, the radiation It has a negative value when the source moves to the receiver side, and a positive value when the radiation source moves to the side opposite to the receiver side, where d is the size or diameter of the test subject is there.) In the arithmetic processing, when the object to be irradiated is moved in a direction parallel to the irradiation axis of the radiation from the radiation source, one or more simultaneous equations of the following equation (1) and the following equation (3) are used: At least one of the size (d) of the object to be inspected, the enlargement ratio (D / d) of the image, and the positional relationship (a) between the radiation source and the object to be inspected is determined. 11. The fluoroscopic nondestructive inspection device according to any one of Items 8 to 10.

(Wherein, a ₀ , b ₀ , and D ₀ are respectively the distance from the position of the radiation source at the initial position to the subject, the distance from the radiation source to the receiver, and the receiver I is an integer from 1 to n, and D _i and M _i are the objects to be irradiated when the object is moved n times along an axis horizontal to the irradiation axis. Is the size of the image the subject makes on the receiver when it is placed at the i-th position, and the moving distance from the first position of the subject to the i-th position, where M _i is the subject. When the irradiator moves toward the image receiver, it takes a positive value, and when the irradiated object moves away from the image receiver, it takes a negative value, where d is the size of the object under test. Or diameter) In the arithmetic processing, when the object to be irradiated is moved in any one axial direction in the surface inner diameter direction perpendicular to the irradiation axis of the radiation from the irradiation source, the following formula (1) and the following formula (4) And / or at least one of the size (d) of the inspection object, the magnification ratio (D / d) of the image, and the positional relationship (a) between the radiation source and the inspection object, using one or more simultaneous expressions of The radiographic nondestructive inspection apparatus according to any one of claims 8 to 10, wherein one is determined.

Where D ₀ , a ₀ , and b ₀ are respectively the size of the image made by the subject at the receiver at the first position, the distance from the position of the radiation source to the subject, and Where j is an integer from 1 to s, and D _j , H _j , and H _j ′ are arbitrary in-plane radial directions perpendicular to the radiation irradiation axis of the object to be irradiated The size of the image the subject under test makes on the receiver when placed at the j-th position of the illuminated object when moving s times along one axis of the subject, j-th from the first position of the illuminated object And the movement distance from the first position of the image formed on the image receiver to the j-th position, where d is the size or diameter of the test subject). In the arithmetic processing, in the case where the radiation source is moved in any one axis direction in the in-plane direction perpendicular to the irradiation axis of the radiation from the irradiation source, the following Expression (1) and Expression (5) At least one of the size (d) of the inspection object, the magnification ratio (D / d) of the image, and the positional relationship (a) between the radiation source and the inspection object using one or more simultaneous expressions. The radiographic nondestructive inspection apparatus according to any one of claims 8 to 10, wherein

Where D ₀ , a ₀ , and b ₀ are respectively the size of the image made by the subject at the receiver at the first position, the distance from the position of the radiation source to the subject, and The distance to the receiver of j is an integer from 1 to t, and D _j , G _j , and G _j ′ are any in-plane radial directions perpendicular to the radiation irradiation axis of the radiation source. The size of the image that the object under test produces on the receiver when placed at the j-th position of the radiation source when moving t times along one axis, from the first position of the radiation source to the j-th position And the movement distance from the first position of the image formed on the image receiver to the j-th position, where d is the size or diameter of the test subject). In the arithmetic processing, when the radiation source is moved in an in-plane oblique direction of a plane formed by an axis parallel to the irradiation axis of the radiation from the radiation source and an arbitrary uniaxial axis in an inner radial direction perpendicular to the plane At least one of the size of the inspection object, the magnification of the image, and the distance between the radiation source and the inspection object, using a simultaneous expression consisting of one or more of the following expressions (1) and (6): The radiographic nondestructive inspection apparatus according to any one of claims 8 to 10, wherein one or the other is geometrically calculated and estimated.

(Wherein, a ₀ , b ₀ , and D ₀ are respectively the distance from the position of the radiation source at the initial position to the subject, the distance from the radiation source to the receiver, and the receiver _K is an integer from 1 to p, and a _k , I _k and I _k ′ are in-plane directions in which the radiation source is located in an axis horizontal and perpendicular to the radiation irradiation axis When the movement distance from the first position of the radiation source to the k-th position is projected on an axis parallel to the radiation irradiation axis when moving p times in the in-plane oblique direction of the plane formed by any one axis of Value, the value obtained by projecting the movement distance from the first position of the inspection object to the k-th position onto the arbitrary one axis in the surface radial direction perpendicular to the radiation irradiation axis, and the image receiver The arbitrary one axial direction from the first position to the k-th position of the center of the image Is of a moving distance .d a size or diameter of the device under test.)

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