JP7110697B2 - X-ray imaging device - Google Patents

Description

The present invention relates to an X-ray imaging apparatus, and more particularly to an X-ray imaging apparatus that produces a dark field image.

Conventionally, an X-ray imaging apparatus that generates a dark field image is known (see, for example, Non-Patent Document 1).

Non-Patent Document 1 above discloses an X-ray imaging apparatus that generates a dark-field image of an object using a Talbot-Lau interferometer. The “dark-field image” is a visibility image obtained by changes in visibility based on small-angle scattering of an object. A dark-field image is also called a small-angle scattering image. "Visibility" is definition.

Here, when taking a dark-field image, if the scattering of X-rays due to the internal structure of the object has directivity, the internal structure may change depending on the relationship between the orientation of the grating and the orientation of the object with respect to the grating (scattering direction). may not be converted. Specifically, among X-ray scattering directions caused by the internal structure of the subject, X-rays scattered in a direction perpendicular to the direction of the grating are emphasized, so that the internal structure is imaged. However, X-rays scattered along the direction of the grid are hardly imaged (no sensitivity), so there is a disadvantage that it may be difficult to image the internal structure in detail depending on the orientation of the subject with respect to the grid. . Therefore, in Non-Patent Document 1, the internal structure of the subject is imaged in detail by changing the orientation of the subject with respect to the orientation of the lattice. It should be noted that the orientation of the grid means the direction in which the grid pattern extends.

Florian Schaff et al., Correlation of X-Ray Vector Radiography to Bone Micro-Architecture, Scientific Reports 4, Article number;3695(2014), doi:10.1038/srep03695

However, in Non-Patent Document 1, in order to image the internal structure according to the direction of the subject, it is necessary to change the direction of the subject and take an image. Therefore, in order to image the internal structure of the subject, the subject is arranged in a plurality of directions and photographed. As a result, for example, when comparing X-ray contrast images captured by changing the orientation of the subject with respect to the grid in order to image the internal structure of the subject, it is necessary to match the orientation of the subject in each image. occurs.

The present invention has been made to solve the above problems, and one object of the present invention is to make it possible to image the internal structure of a subject without changing the orientation of the subject with respect to the grid. It is also an object of the present invention to provide an X-ray imaging apparatus that eliminates the need to match the direction of a subject in each image.

To achieve the above object, an X-ray imaging apparatus according to a first aspect of the present invention comprises: an X-ray source; a plurality of gratings including a second grating for interfering with the self-image of one grating; a detector for detecting X-rays emitted from an X-ray source; a plurality of grating rotating mechanisms for individually rotating a plurality of gratings in a plane orthogonal to the axial direction; and an image processing unit for generating at least a dark field image from the X-ray intensity distribution detected by the detector. , and a grating moving mechanism for moving at least one of the plurality of gratings, and the image processing unit arranges the gratings at a plurality of angles in a plane perpendicular to the optical axis direction. The grating moving mechanism is configured to move the grating vertically or horizontally in a plane orthogonal to the optical axis direction, and moves at least one of the plurality of gratings. When one of the lattices is arranged in an oblique direction, any one of the plurality of lattices is moved in the vertical direction or the horizontal direction in which the translational distance becomes smaller according to the arrangement angle of the plurality of lattices. is configured as

In the X-ray imaging apparatus according to the first aspect of the present invention, as described above, there are provided a plurality of grating rotating mechanisms for individually rotating a plurality of gratings, and a dark field imaged by arranging the gratings at a plurality of angles. and a grating moving mechanism for moving at least one of a plurality of gratings, wherein the grating moving mechanism moves the grating vertically or horizontally in a plane perpendicular to the optical axis direction. and when at least one of the plurality of grids is arranged in an oblique direction, translational movement in either the vertical direction or the horizontal direction according to the arrangement angle of the plurality of grids is configured to move any one of the plurality of grids in a direction in which the distance between the grids becomes smaller . Accordingly, by changing the orientation of the grid, the orientation of the subject with respect to the grid can be changed without changing the orientation of the subject with respect to the grid. Therefore, the internal structure of the object can be imaged without changing the orientation of the object with respect to the grid. In addition, it is possible to image the internal structure of the object without changing the orientation of the object with respect to the grating. It is not necessary to match the direction of the subject in the image, and each image can be easily compared.

In the X-ray imaging apparatus according to the first aspect, preferably, the grating rotating mechanism has a plurality of gratings in at least any two of the longitudinal direction, the lateral direction, and the oblique direction within a plane orthogonal to the optical axis direction. It is configured to arrange a grid. With this configuration, when the grids are rotated, the plurality of grids can be rotated so that the orientations of the grids with respect to the orientation of the subject are different from each other. As a result, it is possible to image the internal structures of the subject with different X-ray scattering directions.

In this case, preferably , the grid moving mechanism is configured to move at least one of the plurality of grids together with the grid rotating mechanism after rotating the plurality of grids. With this configuration, even when the grids are moved after rotating the plurality of grids, the grids can be moved without rotating the grid moving mechanism.

In this case, preferably, when any one of the plurality of gratings is translated by at least one grating period, the grating moving mechanism moves any one of the plurality of gratings in a direction in which the distance of the translational movement becomes smaller. is configured to move With this configuration, even when the grating is arranged at a plurality of angles and translated, the grating can be translated in a direction in which the translation distance of the grating becomes smaller according to the arrangement angle of the grating. As a result, it is possible to suppress the deterioration of the image quality of the image caused by the error in the translational movement.

In the configuration for changing the direction in which the grids are moved according to the arrangement direction of the plurality of grids, preferably, the grid rotation mechanism includes a grid holding portion that holds the grid and a rotation portion that rotates the grid holding portion. including. With this configuration, the size of the grating rotating mechanism can be reduced by rotating the grid holding section by the rotating section, compared to the case where the grid is rotated together with the grid moving mechanism. In addition, since the grating can be rotated by the grating rotating mechanism, there is no need for a mechanism for rotating the grating moving part with the rotation of the grating, so that the device configuration can be simplified accordingly. .

In this case, preferably, the lattice rotation mechanism further includes a stopper mechanism for switching between a state in which the lattice can be rotated and a state in which the lattice cannot be rotated. With this configuration, by keeping the grid in a non-rotatable state when the subject is imaged, unintended rotation of the grid, such as malfunction of the grid rotating section, can be suppressed. As a result, it is possible to suppress the occurrence of unintended positional deviation in the rotation direction of the grating about the optical axis after the orientation of the grating is changed by the grating rotation mechanism and before the imaging is performed.

In the structure in which the grid rotation mechanism includes a stopper mechanism, the stopper mechanism preferably includes an abutting member that abuts against the grid holding portion, a biasing member that biases the abutting member against the grid holding portion, and a biasing member. an abutment release portion for separating the abutment member from the grid holding portion against the biasing force of the member. According to this structure, by actuating the abutment state releasing portion, the grid can be switched from a state in which the grid cannot be rotated due to the biasing force of the biasing member to a state in which the grid can be rotated. As a result, it is possible to make the grating rotatable only when the orientation of the grating is to be changed, so that the rotational displacement of the grating can be suppressed as much as possible with a simple structure.

In the structure in which the lattice rotation mechanism includes the lattice holding portion and the rotation portion, the lattice rotation mechanism preferably further includes an origin position detection portion for detecting the origin position of the lattice. With this configuration, when rotating each grid, it is possible to easily confirm whether or not each grid is arranged at the origin position. As a result, when rotating each grid, each grid can be easily arranged in the initial position.

In the structure in which the grating rotating mechanism includes a grating holding part and a rotating part, it is preferably provided separately from the grating rotating mechanism and is used to adjust the angular deviation of the plurality of gratings in the rotating direction around the X-ray irradiation axis. A grating angle fine adjustment mechanism for fine adjustment is further provided, and the grating rotation mechanism is configured to be held on the grating moving mechanism via the grating angle fine adjustment mechanism . With this configuration, even when the grating is rotated by the grating rotating mechanism, the position of the grating can be adjusted and the grating can be moved without rotating the grating angle fine adjustment mechanism and the grating moving mechanism. As a result, it is not necessary to rotate the grating angle fine adjustment mechanism and the grating moving mechanism with the rotation of the grating.

In the configuration including the grating angle fine adjustment mechanism , preferably, the control unit further includes a control unit that calculates the adjustment amount of the grating by the grating angle fine adjustment mechanism based on moire fringes generated after the plurality of gratings are rotated by the grating rotation mechanism. Prepare. With this configuration, even if the relative positions of the plurality of gratings are displaced by rotating the gratings, it is possible to calculate the adjustment amount of the gratings based on the moire fringes. , the position of the grid can be easily adjusted.

The X-ray imaging apparatus according to the first aspect preferably further includes a grating angle information storage section that stores angle information of the plurality of gratings rotated by the grating rotating mechanism. With this configuration, it is possible to easily grasp the direction of the scattering component at the time of image analysis.

The X-ray imaging apparatus according to the first aspect preferably further comprises a rotation mechanism for relatively rotating an imaging system configured by an X-ray source, a detector, and a plurality of gratings and a subject, wherein the image processing unit comprises: A three-dimensional dark field image is generated from a plurality of dark field images captured at a plurality of rotation angles while the subject and the imaging system are relatively rotated. Here, since the direction of X-ray scattering that is emphasized also differs depending on the direction of the rotation axis and the orientation of the grating when relative rotation is performed between the subject and the imaging system, Sometimes you want to change the direction of the axis of rotation. In addition, there are cases where it is desired to change the orientation of the subject with respect to the rotation axis when performing relative rotation between the subject and the imaging system. With the above configuration, a three-dimensional dark-field image captured by changing the orientation of the subject with respect to the grid can be generated without changing the direction of the rotation axis when performing relative rotation between the subject and the imaging system. can be done. In addition, it is possible to generate a three-dimensional dark field image captured by changing the orientation of the subject with respect to the grid without changing the orientation of the subject. As a result, there is no need to combine a mechanism for changing the direction of the rotation axis and a mechanism for changing the orientation of the subject when relative rotation is performed between the subject and the imaging system, thereby avoiding complication of the apparatus configuration. can be suppressed.

An X-ray imaging apparatus according to a second aspect of the present invention comprises an X-ray source, a first grating for forming a self-image by X-rays emitted from the X-ray source, and interference with the self-image of the first grating. a detector for detecting X-rays emitted from an X-ray source; and a plurality of gratings that rotate in a plane perpendicular to the optical axis direction of the X-rays. and an image processing unit that generates at least a dark field image from the X-ray intensity distribution detected by the detector. The image processing unit is configured to generate a dark field image captured by arranging the gratings at a plurality of angles, and the image processing unit is configured to arrange the gratings at a plurality of angles in a plane orthogonal to the optical axis direction. The image processing unit is configured to synthesize a plurality of dark-field images to generate a total scattering image representing the intensity of scattering of X-rays by the subject, and the image processing unit uses the plurality of dark-field images in which the angles of the gratings are different. and at least one of a scattering directivity image representing the directivity of X-ray scattering by the subject and a directivity intensity image representing the intensity of the directivity of X-ray scattering by the subject. It is Here, since the dark-field image is imaged based on the scattering of X-rays in the subject, the sensitivity differs according to the orientation of the grating (some scattered rays cannot be imaged). With the above configuration, the omnidirectional scattering image that compensates for the difference in X-ray scattering sensitivity is generated by synthesizing a plurality of dark field images in which X-rays are scattered in a plurality of directions. image can be obtained. In addition, since it is possible to capture an image without changing the direction of the subject, it is possible to generate a total scattering image without adjusting the position of the subject. As a result, a total scattering image can be easily and accurately generated. Also , by generating a scattering directivity image, it is possible to grasp the scattering of X-rays by the object. In addition, by generating a directivity intensity image, it is possible to grasp the intensity of the directivity of X-ray scattering by the object. As a result, it is possible to grasp in more detail the distribution of a plurality of internal structures with different scattering directivities within the subject, the distribution of defects occurring within the subject, and the like.

In the configuration in which the image processing unit generates the scattering directivity image, the image processing unit is preferably configured to generate the scattering directivity image in which the X-ray scattering directivity and the color are associated and displayed. . With this configuration, since the X-ray scattering directivity and the color are associated with each other in the scattering directivity image, for example, a scattering directivity in which the difference in directivity is displayed by the difference in pixel values (brightness and darkness of the image). Directivity of X-ray scattering can be easily grasped by comparison with the image.

In the X-ray imaging apparatus according to the first and second aspects, the image processing unit is preferably configured to acquire the feature amount of the subject from an image generated by synthesizing a plurality of dark field images. . With this configuration, accurate synthesis can be performed without the need for alignment, so feature amounts can be obtained easily and with high accuracy.

In the X-ray imaging apparatus according to the first and second aspects, preferably, the image processing unit is configured to acquire information about an internal structure having directivity within the subject as the feature amount of the subject, The information about the directional internal structure in the object includes at least the directional internal structure length and the directional internal structure width. By configuring in this way, for example, the shape of the directional internal structure such as the internal structure of carbon fiber reinforced plastic can be grasped in more detail.

In the X-ray imaging apparatus according to the first and second aspects, preferably the plurality of gratings further includes a third grating arranged between the X-ray source and the first grating. With this configuration, the coherence of X-rays emitted from the X-ray source can be enhanced by the third grating. As a result, it is possible to form a self-image of the first grating without depending on the focal size of the X-ray source, thereby improving the degree of freedom in selecting the X-ray source.

In this case, preferably, the plurality of gratings are adjusted in relative position between any one of the plurality of gratings so that the second grating and the third grating are relative and symmetrical with respect to the first grating. It is configured to be arranged in an appropriate relative position. With this configuration, any one of the first grid, the second grid, and the third grid is arranged at a relative and symmetrical relative position with respect to the first grid, whereby a plurality of Since it is possible to adjust the positions of the grids, it is possible to easily adjust the relative positions between the grids of the plurality of grids .

According to the present invention, as described above, it is possible to image the internal structure of a subject without changing the orientation of the subject with respect to the grid, and at the same time, X-ray imaging is possible without the need to match the orientation of the subject in each image. An imaging device can be provided.

1 is a schematic diagram of the X-ray imaging apparatus according to the first embodiment viewed from the X direction; FIG. FIG. 4 is a schematic diagram for explaining a grating rotation mechanism in the X-ray imaging apparatus according to the first embodiment; It is the schematic diagram (A) which has arrange|positioned the direction of the grating|lattice horizontally by a grating|lattice rotation mechanism, the schematic diagram (B) which has arrange|positioned it diagonally, and the schematic diagram (C) which has arrange|positioned vertically. FIG. 4 is a schematic diagram for explaining a grating position adjusting mechanism and a grating moving mechanism in the X-ray imaging apparatus according to the first embodiment; FIG. 4 is a schematic diagram for explaining the position adjustment of the grating by the grating position adjustment mechanism in the X-ray imaging apparatus according to the first embodiment; 4A to 4C are schematic diagrams for explaining the moving direction of the grating by the grating moving mechanism in the X-ray imaging apparatus according to the first embodiment; FIG. 4 is a flowchart for explaining an imaging method by the X-ray imaging apparatus according to the first embodiment; Schematic diagram (A) of a dark-field image captured by arranging the grating horizontally and imaged by the X-ray imaging apparatus according to the first embodiment, and a schematic diagram of a dark-field image captured by arranging the grating vertically. It is a figure (B). 8 is a flowchart for explaining an imaging method by the X-ray imaging apparatus according to the second embodiment; Schematic diagram (A) of a dark-field image captured by the X-ray imaging apparatus according to the second embodiment with the gratings arranged horizontally, and a schematic diagram of a dark-field image captured with the gratings arranged vertically. (B) and a dark-field image (C) obtained by synthesizing them. 10 is a flow chart for explaining an imaging method by the X-ray imaging apparatus according to the third embodiment; 7A to 7D are schematic diagrams (A) to (D) of dark-field images captured by changing the orientation of the grating according to the third embodiment. FIG. 11 is a schematic diagram of a scattering directivity image generated by an image processing unit according to the third embodiment; FIG. 11 is a schematic diagram of a directional strong/weak image generated by an image processing unit according to the third embodiment; FIG. 11 is a schematic diagram of the grating rotation mechanism of the X-ray imaging apparatus according to the fourth embodiment, viewed from the Z1 direction; FIG. 12 is a schematic diagram of the grating rotation mechanism of the X-ray imaging apparatus according to the fourth embodiment, viewed from the Z2 direction; FIG. 12 is a schematic diagram of the X-ray imaging apparatus according to the fifth embodiment as seen from the X direction; FIG. 14 is a flowchart for explaining an imaging method by the X-ray imaging apparatus according to the fifth embodiment; FIG. FIG. 4 is a schematic diagram of an X-ray imaging apparatus according to a first modified example of the first embodiment, viewed from the X direction;

Embodiments embodying the present invention will be described below with reference to the drawings.

[First embodiment]
A configuration of an X-ray imaging apparatus 100 according to a first embodiment of the present invention and a method for generating a dark field image 13 by the X-ray imaging apparatus 100 will be described with reference to FIGS. 1 to 8. FIG.

(Configuration of X-ray imaging device)
First, the configuration of an X-ray imaging apparatus 100 according to the first embodiment will be described with reference to FIG.

As shown in FIG. 1, the X-ray imaging apparatus 100 is an apparatus that images the inside of a subject T using scattering of X-rays that have passed through the subject T. As shown in FIG. Also, the X-ray imaging apparatus 100 is an apparatus that images the inside of the subject T using the Talbot effect. The X-ray imaging apparatus 100 can be used, for example, for imaging the inside of a subject T as an object in nondestructive inspection applications.

The subject T includes directional internal structures. Subject T is, for example, carbon fiber reinforced plastic (CFRP). In addition, the internal structure with directivity means an internal structure having a characteristic in the direction in which X-rays are scattered in each internal structure. That is, the directional internal structure is an internal structure that scatters X-rays in a predetermined direction.

FIG. 1 is a diagram of the X-ray imaging apparatus 100 viewed from the X direction. As shown in FIG. 1, the X-ray imaging apparatus 100 includes an X-ray source 1, a first grating 2, a second grating 3, a detector 4, an image processing unit 5, a control unit 6, a grating circuit. A driving mechanism 7 , a grid moving mechanism 8 , and a grid position adjusting mechanism 9 are provided. In this specification, the direction from the X-ray source 1 to the first grating 2 is the Z2 direction, and the opposite direction is the Z1 direction. Further, the horizontal direction in a plane perpendicular to the Z direction is defined as the X direction, the direction toward the back of the paper surface of FIG. 1 is the X2 direction, and the direction toward the front side of the paper surface of FIG. 1 is the X1 direction. The vertical direction in a plane perpendicular to the Z direction is the Y direction, the upward direction is the Y1 direction, and the downward direction is the Y2 direction. Also, the Z direction is an example of the "X-ray optical axis direction" in the scope of claims. Moreover, the lattice position adjusting mechanism 9 is an example of the "lattice angle fine adjusting mechanism" in the claims.

The X-ray source 1 generates X-rays by applying a high voltage. The X-ray source 1 is configured to irradiate the generated X-rays in the Z2 direction.

The first grating 2 has a plurality of slits 2a and X-ray phase changing portions 2b. The slits 2a and the X-ray phase changing portions 2b are arranged at a predetermined period (pitch) d1 in the Y direction. Each slit 2a and X-ray phase changing portion 2b are formed to extend linearly. Moreover, each slit 2a and the X-ray phase change portion 2b are formed so as to extend in parallel. The first grating 2 is a so-called phase grating.

The first grating 2 is arranged between the X-ray source 1 and the second grating 3 and is irradiated with X-rays from the X-ray source 1 . The first grating 2 is provided for forming a self-image 12 (see FIG. 6) of the first grating 2 by the Talbot effect. When coherent X-rays pass through a slit-formed grating, an image of the grating (self-image 12) is formed at a predetermined distance (Talbot distance) from the grating. This is called the Talbot effect.

The second grating 3 has a plurality of X-ray transmitting portions 3a and X-ray absorbing portions 3b. The X-ray transmitting portions 3a and the X-ray absorbing portions 3b are arranged at a predetermined period (pitch) d2 in the Y direction. Each X-ray transmitting portion 3a and each X-ray absorbing portion 3b are formed to extend linearly. Each X-ray transmitting portion 3a and each X-ray absorbing portion 3b are formed so as to extend in parallel. The second grating 3 is a so-called absorption grating. Although the first grating 2 and the second grating 3 are gratings having different roles, the slits 2a and the X-ray transmitting portion 3a respectively transmit X-rays. Also, the X-ray absorbing portion 3b shields X-rays. Also, the X-ray phase changing portion 2b changes the phase of X-rays due to the difference in refractive index from that of the slit 2a.

The second grating 3 is arranged between the first grating 2 and the detector 4 and is irradiated with X-rays passing through the first grating 2 . Also, the second grating 3 is arranged at a position separated from the first grating 2 by a predetermined Talbot distance. The second grating 3 interferes with the self-image 12 of the first grating 2 to form moiré fringes 11 (see FIG. 5) on the detection surface of the detector 4 .

The detector 4 is configured to detect X-rays, convert the detected X-rays into electrical signals, and read the converted electrical signals as image signals. Detector 4 is, for example, an FPD (Flat Panel Detector). The detector 4 is composed of a plurality of conversion elements (not shown) and pixel electrodes (not shown) arranged on the plurality of conversion elements. A plurality of conversion elements and pixel electrodes are arranged in an array in the X and Y directions with a predetermined period (pixel pitch). Further, the detector 4 is configured to output the acquired image signal to the image processing section 5 .

The image processing section 5 is configured to generate a dark field image 13 (see FIG. 8) based on the image signal output from the detector 4 . The image processing unit 5 includes a processor such as a GPU (Graphics Processing Unit) or an FPGA (Field-Programmable Gate Array) configured for image processing.

The control unit 6 is configured to change the orientation of the grid with respect to the subject T by rotating the grid via the grid rotating mechanism 7 . Further, the control unit 6 is configured to be able to move the first grating 2 in the vertical direction (Y direction) or the horizontal direction (X direction) within the grating plane via the grating moving mechanism 8 . Further, the control unit 6 is configured to change the direction in which the grid is moved according to the direction in which the grid is arranged. The control unit 6 also includes a lattice angle information storage unit 10 that stores angle information of a plurality of lattices rotated by the lattice rotation mechanism 7 . Control unit 6 includes, for example, a processor such as a CPU (Central Processing Unit).

The grid rotating mechanism 7 is configured to rotate the first grid 2 and the second grid 3 based on a signal from the control section 6 . Specifically, the grid rotation mechanism 7 is provided on each of the first grid 2 and the second grid 3 . The grating rotation mechanism 7 rotates a plurality of gratings in at least two of the vertical direction (Y direction), horizontal direction (X direction), and oblique directions in a plane perpendicular to the optical axis direction (Z direction). configured to be placed. Further, the grid rotation mechanism 7 is configured to change the orientation of the grid with respect to the subject T by rotating the grid. A detailed configuration for rotating the grid by the grid rotating mechanism 7 will be described later. Note that the vertical direction means that the direction in which the gratings are arranged is approximately 90 degrees with respect to the horizontal direction (X direction) orthogonal to the optical axis direction (Z direction) of X-rays. Further, the horizontal direction means that the direction in which the gratings are arranged is approximately 0 degrees when the horizontal direction (X direction) orthogonal to the optical axis direction (Z direction) of X-rays is used as a reference. Further, the oblique direction means that the direction in which the grids are arranged is approximately plus or minus 45 degrees. It should be noted that each direction allows a deviation within a range of a predetermined angle. The deviation within the predetermined angle range may be plus or minus 15 degrees or plus or minus 5 degrees, for example. Typically, the vertical direction (Y direction) is the vertical direction and the horizontal direction (X direction) is the horizontal direction.

The grating moving mechanism 8 is configured to be able to move the first grating 2 in the vertical direction (Y direction) or the horizontal direction (X direction) based on a signal from the control unit 6 . A detailed configuration for moving the grid by the grid moving mechanism 8 will be described later. Further, the grid moving mechanism 8 holds the grid rotating mechanism 7 via the grid position adjusting mechanism 9 .

The grid position adjustment mechanism 9 is configured to adjust the relative position between the grids of the first grid 2 based on the signal from the control unit 6 . A detailed configuration for adjusting the relative positions between the plurality of grids by the grid position adjustment mechanism 9 will be described later.

The lattice angle information storage unit 10 is configured to store lattice angle information of a plurality of lattices rotated by the lattice rotation mechanism 7 based on the signal from the control unit 6 . The lattice angle information storage unit 10 is composed of, for example, an HDD (Hard Disk Drive) and a memory.

In the first embodiment, the image processing unit 5 generates a dark-field image 13 captured by arranging gratings at a plurality of angles in a plane (XY plane) perpendicular to the optical axis direction (Z direction). is configured as Specifically, the image processing unit 5 generates a dark field image 13 (see FIG. 8) captured while the first grating 2 is translated by the control unit 6 via the grating moving mechanism 8 . Here, the dark field image is an image of the contrast generated by the refraction of X-rays by the internal structure inside the subject T. As shown in FIG. Further, in the first embodiment, the image processing unit 5 rotates the first grating 2 and the second grating 3 through the grating rotation mechanism 7 by the control unit 6, thereby rotating the gratings at a plurality of angles. It is configured to generate a plurality of arranged and captured dark field images 13 .

(Lattice rotation mechanism)
Next, the configuration of the grating rotation mechanism 7 in the X-ray imaging apparatus 100 according to the first embodiment will be described with reference to FIG.

As shown in FIG. 2 , the grid rotating mechanism 7 includes a grid holding portion 70 that holds the grid, a rotating portion 71 that rotates the grid holding portion 70 , and a housing 72 . The lattice holder 70 is rotatably supported within the housing 72 . Further, the grid holding part 70 is configured to hold the grid inside while in contact with the grid. Moreover, the grating|lattice holding|maintenance part 70 is formed in disk shape. Further, the grid holding portion 70 has a gear-shaped outer peripheral surface. In the example shown in FIG. 2, the lattices (lattice patterns) are shown large for the sake of convenience so that the orientation of the lattices can be seen. difficult to determine. Therefore, in the first embodiment, the grid holder 70 is provided with the first marker 73a, the second marker 73b and the third marker 73c so that the user can check the rotation of the grid. In addition, as shown in FIG. 2, the first marker 73a, the second marker 73b and the third marker 73c are configured to be mutually identifiable. The lattice pattern is the slit 2a, the X-ray phase changing portion 2b, the X-ray transmitting portion 3a, the X-ray absorbing portion 3b, and the like.

Rotating portion 71 includes a power portion (not shown) and a rotating portion 71a. The power unit includes motors, encoders, and the like. The rotating portion 71a is formed in a disc shape. Further, the rotating portion 71a has a gear-shaped outer peripheral surface. Further, the rotating portion 71a is configured to be rotated by the power portion. The grating holding portion 70 and the rotating portion 71 (rotating portion 71a) are formed so as to be engaged with each other (the gears are engaged with each other). The lattice holding part 70 is formed so as to rotate. Therefore, in the lattice rotation mechanism 7, the rotation portion 71 is rotated based on a signal from the control portion 6, and the rotation of the rotation portion 71 rotates the lattice holding portion 70, thereby rotating the lattice. configured to move. Note that the movable range of the rotating portion 71 may be any range. For example, it may be configured to rotate within a range of approximately 0 degrees to approximately 360 degrees, or may be configured to rotate within a range of approximately 0 degrees to approximately 180 degrees. Further, it may be configured to rotate within a range of approximately minus 90 degrees to approximately 90 degrees. In the first embodiment, the rotating portion 71 is configured to be movable within a range of approximately 0 degrees to approximately 90 degrees. Also, the rotation angle θ (see FIG. 6) of the rotation portion 71 is stored in the lattice angle information storage portion 10 by an encoder or the like included in the rotation portion 71 . That is, the angle θ at which each grid is rotated by the grid rotating mechanism 7 is stored in the grid angle information storage unit 10 .

3A to 3C are schematic diagrams showing the rotation of the lattice by the lattice rotation mechanism 7. FIG. FIG. 3A is a schematic diagram when the lattice is arranged in the horizontal direction (X direction). FIG. 3(B) is a schematic diagram when the grid is arranged obliquely. FIG. 3(C) is a schematic diagram when the grid is arranged in the vertical direction (Y direction). In the first embodiment, the control unit 6 rotates each grid via the grid rotation mechanism 7, thereby arranging the grids in the directions shown in FIGS. can be done. The grating turning mechanism 7 is configured so that the turning angles θ of the respective gratings are substantially the same. In the first embodiment, the X-ray imaging apparatus 100 is configured to capture an image of the subject T with the grid facing vertically (Y direction) and horizontally (X direction). Note that the orientation of the lattice is the direction in which the lattice pattern extends.

(Grid moving mechanism and grid position adjusting mechanism)
As shown in FIG. 4, the grating moving mechanism 8 can move the grating vertically (Y direction) or horizontally (X direction) in a plane (XY plane) perpendicular to the optical axis direction (Z direction). is configured to Specifically, as shown in FIG. 4 , the grating moving mechanism 8 includes an X-direction linear motion mechanism 80 and a Y-direction linear motion mechanism 81 . The X-direction linear motion mechanism 80 is configured to be translatable in the X-direction. X-direction linear motion mechanism 80 includes, for example, a stepping motor. The Y-direction linear motion mechanism 81 is configured to be translatable in the Y-direction. Y-direction direct-acting mechanism 81 includes, for example, a stepping motor. The grating moving mechanism 8 is configured to translate the grating rotating mechanism 7 in the X direction via the grating position adjusting mechanism 9 by the operation of the X-direction translational mechanism 80 . The grating moving mechanism 8 is configured to translate the grating rotating mechanism 7 in the Y direction via the grating position adjusting mechanism 9 by the operation of the Y-direction direct-acting mechanism 81 . That is, the grid moving mechanism 8 is configured to move the first grid 2 together with the grid rotating mechanism 7 .

Moreover, as shown in FIG. 4, the grid position adjusting mechanism 9 is held on the grid moving mechanism 8 . The grating position adjustment mechanism 9 includes a stage support section 90 , a drive section 91 and a stage 92 . The stage support section 90 supports the stage 92 from below (Y1 direction). The drive section 91 is configured to reciprocate the stage support section 90 in the X direction. The stage 92 has a convex curved bottom portion facing the stage support portion 90, and is configured to rotate about a central axis in the Z direction by reciprocating in the X direction. Unlike the lattice rotation mechanism 7 that changes the orientation of each lattice by largely rotating each lattice, the lattice position adjustment mechanism 9 is a mechanism that adjusts minute angular deviations in the XY plane of the lattice. Therefore, the grid position adjusting mechanism 9 is configured to have higher positional accuracy than the grid rotating mechanism 7 . In addition, the grid position adjusting mechanism 9 is configured such that the amount of grid rotation is smaller than that of the grid rotating mechanism 7 .

(Grid position adjustment)
Next, with reference to FIG. 5, a configuration in which the control unit 6 adjusts the positions of the first grating 2 and the second grating 3 will be described. The example shown in FIG. 5A is a schematic diagram of an image after the first grating 2 and the second grating 3 are rotated by the grating rotating mechanism 7. FIG. After the grating rotation mechanism 7 rotates the gratings, the relative positions of the first grating 2 and the second grating 3 may shift. When the relative positions of the first grating 2 and the second grating 3 are displaced, moire fringes 11 are generated as shown in FIG. In the example shown in FIG. 5A, moire fringes 11 with a period of d3 are generated.

ここで、ｇａは格子の調整量である。また、ｄ２は、第２格子３の格子ピッチである。また、ｄ３はモアレ縞１１のピッチである。また、ｓは検出器４の画素サイズである。 In the first embodiment, the controller 6 controls the adjustment amount of the grid by the grid position adjustment mechanism 9 based on the moire fringes 11 generated after the grid rotation mechanism 7 rotates the first grid 2 and the second grid 3. It is configured to calculate ga. Specifically, the control unit 6 calculates the grid adjustment amount ga by the following equation (1).

where ga is the adjustment amount of the grid. Also, d2 is the grating pitch of the second grating 3 . Also, d3 is the pitch of the moire fringes 11 . Also, s is the pixel size of the detector 4 .

The control unit 6 calculates the adjustment amount ga of the grid using the above equation (1), and rotates the first grid 2 by the grid position adjustment mechanism 9 by the calculated adjustment amount ga. It is configured to perform position adjustment between two gratings 3 . After the positional adjustment between the first grating 2 and the second grating 3, the moire fringes 11 have a sufficiently large period as shown in FIG. 5B, and in some cases substantially disappear.

(Switching the direction of translational movement of the lattice)
Next, with reference to FIG. 6, a configuration in which the control unit 6 in the first embodiment switches the direction of translational movement of the grid by the grid moving mechanism 8 will be described. In the first embodiment, the image processing unit 5 generates the dark field image 13 by the fringe scanning method. The fringe scanning method is a method of generating an image based on a detection signal curve (step curve) of detected X-rays by taking an image while translating the grating for one period or more of the grating. In the first embodiment, the grating moving mechanism 8 is configured to translate the first grating 2 by one period (d2) or more of the second grating 3 . Further, the grid moving mechanism 8 is configured to change the direction of moving the grid according to the arrangement direction of the first grid 2 and the second grid 3 . The grating moving mechanism 8 is configured to move the first grating 2 in a direction in which the distance of the translational movement becomes smaller when the first grating 2 is translated by one period (d2) or more of the second grating 3. there is

ここで、ｓｗｃおよびｓｗｓは、格子を並進移動させる際の並進距離である。また、ｄ２は第２格子３のピッチである。また、θはＸ線の光軸方向（Ｚ方向）に直交する面内（ＸＹ面内）における格子の回動角度である。また、ｎは格子を並進させる回数（ステップ数）である。 Specifically, the control unit 6 is configured to translate the grating in a direction that reduces the translation distance among the translation distances calculated by the following equations (2) and (3).

Here, swc and sws are translational distances when the grid is translated. Also, d2 is the pitch of the second grating 3 . θ is the rotation angle of the grating in a plane (XY plane) orthogonal to the optical axis direction (Z direction) of X-rays. Also, n is the number of times (the number of steps) to translate the grid.

The translational distance swc of the translational movement calculated by the above formula (2) is the movement distance when moving the grating in the vertical direction (Y direction). The translational distance sws of the translational movement calculated by the above equation (3) is the movement distance when moving the grid in the horizontal direction (X direction). The control unit 6 calculates the translational distance swc for translational movement in the horizontal direction (X direction) and the translational distance sws for translational movement in the vertical direction (Y direction), and translates the grid in the direction in which the movement distance becomes smaller. move.

The example shown in FIG. 6A is a schematic diagram showing the translational movement of the grid when the grid is arranged horizontally (in the X direction). When the grid is arranged horizontally (in the X direction), the controller 6 translates the first grid 2 in the Y2 direction via the grid position adjustment mechanism 9 .

The example shown in FIG. 6B is a schematic diagram showing the step direction when the gratings are arranged obliquely. FIG. 6B shows an example in which the rotation angle θ of the lattice is small. In the example shown in FIG. 6B, the rotation angle θ of the lattice is 30 degrees, for example. When the rotation angle θ of the lattice is 30 degrees, the translation distance swc in the vertical direction (Y direction) is smaller than the translation distance sws in the horizontal direction (X direction). Therefore, in the example shown in FIG. 6B, the first grating 2 is translated in the vertical direction (Y direction). The example shown in FIG. 6C is a schematic diagram showing the step direction when the gratings are arranged obliquely. FIG. 6C shows an example in which the rotation angle θ of the lattice is large. In the example shown in FIG. 6C, the rotation angle θ of the grating is, for example, 60 degrees. When the rotation angle θ of the lattice is 60 degrees, the translation distance sws in the horizontal direction (X direction) is smaller than the translation distance swc in the vertical direction (Y direction). Therefore, in the example shown in FIG. 6C, the first grating 2 is translated in the lateral direction (X direction).

(Imaging a subject)
Next, with reference to FIG. 7, the flow of the configuration for imaging the subject T by the X-ray imaging apparatus 100 according to the first embodiment will be described.

In step S<b>1 , the control unit 6 arranges the first grid 2 and the second grid 3 horizontally (in the X direction) via the grid rotation mechanism 7 . Next, in step S2, the subject T is arranged by the operator. Note that step S2 may be performed at any time before step S3.

Next, in step S<b>3 , the control unit 6 takes an image of the subject T while translating the first grating 2 via the grating moving mechanism 8 . Next, the image processing section 5 generates a dark field image 13 of the subject T in step S4.

Next, in step S5, the control unit 6 determines whether or not the first grating 2 and the second grating 3 are imaged with the desired angle. If the first grating 2 and the second grating 3 are not imaged with the desired angle, the process proceeds to step S6. When the image is captured with the first grating 2 and the second grating 3 arranged at the desired angle, the process ends.

In step S6, the control unit 6 rotates the first grid 2 and the second grid 3 by a predetermined angle via the grid rotation mechanism 7, thereby turning the first grid 2 and the second grid 3 vertically (in the Y direction). ). In the first embodiment, the predetermined angle is approximately 90 degrees. Next, in step S<b>7 , the controller 6 adjusts the position of the first grating 2 via the grating position adjusting mechanism 9 . After that, the process proceeds to step S3.

(Image generated by the image processing unit)
Next, an image generated by the image processing unit 5 according to the first embodiment will be described with reference to FIG.

In the first embodiment, the image processing unit 5 arranges the first grating 2 and the second grating 3 at a plurality of angles in a plane (in the XY plane) perpendicular to the optical axis direction (Z direction). is configured to generate a dark field image 13 with a The example shown in FIG. 8 is a dark-field image 13 captured by giving a blow to the object T (CFRP) to form a crack (scratches 14).

Here, the dark-field image 13 is an image based on changes in X-ray dose for each pixel of the detector 4 caused by X-ray scattering. That is, the scattered X-rays that pass through the grating and are detected by the detector 4 are scattered, and the scattered X-rays are absorbed by the grating. will not be detected. On the other hand, the X-rays absorbed by the grating are scattered, and the scattered X-rays pass through the grating, and the scattered X-rays that pass through the grating are detected by the detector 4 become. Therefore, in the dark-field image 13, the dose of X-rays detected at each pixel of the detector 4 changes. When the X-rays scatter in the direction perpendicular to the direction of the grating, the change in the dose of X-rays detected by the detector 4 becomes significant. Also, the scattering of X-rays is caused by the multiple refracting of X-rays by the internal structure of the object T (flaw 14). Refraction of X-rays occurs when the X-rays pass through the boundaries of regions with different refractive indices. When X-rays are refracted by the flaw 14, they are refracted at the boundary between the flaw 14 and other regions, so the X-rays are refracted in a direction intersecting the direction in which the flaw 14 extends. As a result, the dark-field image 13 can capture the directivity of X-ray scattering.

FIG. 8(A) is a dark field image 13a taken with the grating arranged horizontally (in the X direction) (see FIG. 3(A)). In the example shown in FIG. 8A, since the grid is arranged horizontally (in the X direction), among the flaws 14 inside the subject T, the flaw 14a extending in the horizontal direction (X direction) is depicted. . Among the scratches 14 inside the subject T, the scratches 14b and 14c extending in the oblique direction are also depicted. The scratches 14b and 14c extending in the oblique direction contain X-ray scattering components in the horizontal direction (X direction) and the vertical direction (Y direction). be. However, since the amount of X-rays scattered in the vertical direction (Y direction) is smaller for the oblique scratches 14b and 14c than for the horizontal (X direction) scratches 14a, the dark field image 13a shows , is rendered thinner than the scratch 14a extending in the lateral direction (X direction).

A circular area 15 in the dark-field image 13a shown in FIG. The impact narrows (shrinks) the space between the layers in the Z direction of the subject T, weakening the scattering of X-rays, and is therefore displayed in white in the image. Further, in the dark-field image 13a shown in FIG. 8(A), an elliptical region 16a (dotted hatched portion) is caused by delamination of layers in the Z direction in the subject T due to the hitting of the subject T. This is the area drawn by the scattering of X-rays that occurred. An elliptical area 16a is an area where X-rays scattered in the vertical direction (Y direction) due to peeling of the layers of the subject T are detected. In the example shown in FIG. 8A, the angle of each grating stored by the grating angle information storage unit 10 is approximately 0 degrees, and the direction in which the first grating 2 is translated by the grating moving mechanism 8 is , in the Y direction.

FIG. 8(B) is a dark field image 13b taken with the grating arranged vertically (in the Y direction) (see FIG. 3(C)). In the example shown in FIG. 8B, since the grid is arranged vertically (in the Y direction), among the flaws 14 inside the subject T, the flaw 14d extending in the vertical direction (Y direction) is rendered. there is Further, similarly to the dark field image 13a, among the scratches 14 inside the subject T, the scratches 14b and 14c extending in the oblique direction are also depicted. The amount of X-rays scattered in the horizontal direction (X direction) is smaller for the oblique scratches 14b and 14c than for the vertical (Y direction) scratch 14d. It is rendered thinner than the directional flaw 14d. A circular area 15 in the dark-field image 13b shown in FIG.

Further, in the dark-field image 13b shown in FIG. 8B, an elliptical region 16b is caused by scattering of X-rays caused by peeling of layers in the Z direction in the object T when the object T is hit. This is the rendered area. An elliptical region 16b (dotted hatching) is a region where X-rays scattered in the lateral direction (X direction) due to peeling of the layers of the subject T are detected. Therefore, the elliptical region 16b is slightly different in shape from the elliptical region 16a shown in FIG. 8(A). Although illustration is omitted, when each grid is arranged obliquely as shown in FIG. However, the flaw 14b extending in the direction perpendicular to the orientation of the grating is not depicted. Since the scratches 14a and 14d each extend in an oblique direction with respect to the grating, they appear thinner than the scratches 14c in the dark-field image 13 . In the example shown in FIG. 8B, the angle of each grating stored by the grating angle information storage unit 10 is approximately 90 degrees, and the direction in which the first grating 2 is translated by the grating moving mechanism 8 is X is the direction.

(Effect of the first embodiment)
The following effects can be obtained in the first embodiment.

In the first embodiment, as described above, the X-ray imaging apparatus 100 uses the X-ray source 1 and the X-rays emitted from the X-ray source 1 to form the self-image 12 and the first grating 2 and the A plurality of gratings including a second grating 3 for interfering with the self-image 12 of the first grating 2, a detector 4 for detecting X-rays emitted from the X-ray source 1, and an X-ray optical axis direction (Z At least a dark-field image 13 is generated from the grating rotation mechanism 7 that rotates each of the plurality of gratings and the X-ray intensity distribution detected by the detector 4 in a plane (in the XY plane) perpendicular to the direction). The image processing unit 5 generates a dark field image 13 captured by arranging gratings at a plurality of angles in a plane (XY plane) orthogonal to the optical axis direction (Z direction). is configured to generate Accordingly, by changing the orientation of the grid, the orientation of the subject T with respect to the grid can be changed without changing the orientation of the subject T with respect to the grid. Therefore, the internal structure (flaw 14) of the subject T can be imaged without changing the orientation of the subject T with respect to the grid. In addition, since it is possible to image the internal structure (flaw 14) of the subject T without changing the orientation of the subject T with respect to the grid, for example, a dark field image captured by arranging the grid at a plurality of angles 13, it is not necessary to match the orientation of the subject T in each image, and each image can be easily compared.

Further, in the first embodiment, as described above, the grating rotation mechanism 7 moves in the vertical direction (Y direction) and the horizontal direction (X direction) in the plane (XY plane) perpendicular to the optical axis direction (Z direction). direction) and oblique directions, a plurality of grids are arranged in the vertical direction (Y direction) and the horizontal direction (X direction). Thereby, when the grids are rotated, the plurality of grids can be rotated so that the orientation of the grids with respect to the orientation of the subject T is different. As a result, internal structures (wounds 14) in the object T with different X-ray scattering directions can be imaged.

Further, in the first embodiment, as described above, the X-ray imaging apparatus 100 further includes the grating moving mechanism 8 that moves the first grating 2, and the grating moving mechanism 8 rotates the plurality of gratings. , to move the first grid 2 together with the grid rotation mechanism 7 . Thereby, even when the first grating 2 is moved after the first grating 2 and the second grating 3 are rotated, the first grating 2 can be moved without rotating the grating moving mechanism 8 .

Further, in the first embodiment, as described above, the grating moving mechanism 8 moves the grating in the vertical direction (Y direction) or the horizontal direction (in the XY plane) perpendicular to the optical axis direction (Z direction). The first grating 2 is configured to be movable in the X direction), and is configured to change the direction in which the gratings are moved according to the arrangement direction of the plurality of gratings. It is configured to move the first grating 2 in a direction in which the distance of the translational movement becomes smaller when the translational movement is made by d2) or more. As a result, even when the grid is arranged at a plurality of angles and translated, the grid can be translated in a direction in which the translation distance of the grid becomes smaller according to the arrangement direction of the grid. As a result, it is possible to suppress the deterioration of the image quality of the image caused by the error in the translational movement.

Further, in the first embodiment, as described above, the grid rotating mechanism 7 includes the grid holding portion 70 that holds the grid and the rotating portion 71 that rotates the grid holding portion 70 . Thereby, for example, compared with the case of rotating the grid together with the grid moving mechanism 8 , the grid rotating mechanism 7 can be made smaller by rotating the grid holding section 70 with the rotating section 71 . In addition, since the grating can be rotated by the grating rotating mechanism 7, there is no need for a mechanism for rotating the grating moving mechanism 8 with the rotation of the grating. can be done.

Further, in the first embodiment, as described above, the grid position adjusting mechanism 9 for adjusting the relative position between the grids of the plurality of grids of the first grid 2 is further provided. It is configured to be held on the grid moving mechanism 8 via 9 . As a result, even when the grid is rotated by the grid rotating mechanism 7, the position of the grid can be adjusted and the grid can be moved without rotating the grid position adjusting mechanism 9 and the grid moving mechanism 8. FIG. As a result, it is not necessary to rotate the grid position adjusting mechanism 9 and the grid moving mechanism 8 with the rotation of the grid, thereby suppressing the complication of the apparatus configuration.

Further, in the first embodiment, as described above, the X-ray imaging apparatus 100 adjusts the grating position by the grating position adjusting mechanism 9 based on the moire fringes 11 generated after the grating rotation mechanism 7 rotates the plurality of gratings. It further includes a control unit 6 that calculates the adjustment amount ga. As a result, even when the relative positions of the plurality of grids are shifted by rotating the grids, it is possible to calculate the grid adjustment amount ga based on the moire fringes 11. can be adjusted to the position of the grid.

Further, in the first embodiment, as described above, the grid angle information storage unit 10 is further provided for storing the angle information of the plurality of grids rotated by the grid rotation mechanism 7 . This makes it possible to easily grasp the direction of the scattering component at the time of image analysis.

[Second embodiment]
Next, an X-ray imaging apparatus 200 (see FIG. 1) according to the second embodiment will be described with reference to FIGS. 1, 9 and 10. FIG. Unlike the first embodiment in which the dark-field images 13 are generated from the images captured by arranging the gratings in the horizontal direction (X direction) and the vertical direction (Y direction), in the second embodiment, the image processing unit 5 In a plane (XY plane) orthogonal to the optical axis direction (Z direction), a plurality of dark-field images 13 captured by arranging the gratings at a plurality of angles are combined to determine the scattering of X-rays by the subject T. It is arranged to generate an intensity representative total scatter image 20 (see FIG. 10). The total scattering image 20 is an image obtained by imaging X-rays scattered in all directions by the subject T. FIG. Also, the same reference numerals are assigned to the same configurations as in the first embodiment, and the description thereof is omitted.

(Configuration of X-ray imaging device)
First, the configuration of an X-ray imaging apparatus 200 according to the second embodiment will be described with reference to FIG.

In the second embodiment, the image processing unit 5 generates a plurality of dark field images 13 captured by arranging gratings at a plurality of angles in a plane (XY plane) orthogonal to the optical axis direction (Z direction). Combined, they are configured to produce a total scatter image 20 representing the intensity of X-ray scattering by the subject T. FIG. Specifically, the image processing unit 5 synthesizes the dark-field image 13a captured with the grid arranged horizontally (X direction) and the dark-field image 13b captured with the grid arranged vertically (Y direction). and is configured to generate a total scattering image 20 . In the second embodiment, the image processing unit 5 is configured to acquire information about the internal structure (wound 14) having directivity within the subject T as the feature amount of the subject T. Information about the directional internal structure (wound 14) in includes at least the length L (see FIG. 10) of the blemish 14a and the width W (see FIG. 10) of the blemish 14d. The length L of the scratch 14a and the width W of the scratch 14d are examples of the "length of the internal structure with directivity" and the "width of the internal structure with directivity", respectively.

(Method of imaging subject)
Next, with reference to FIG. 9, the flow of the method for imaging the subject T in the X-ray imaging apparatus 200 according to the second embodiment will be described. It should be noted that the description of steps that are the same as in the first embodiment will be omitted.

In steps S1 to S7, a plurality of dark-field images 13 are generated by arranging each grating at a desired angle. After that, the process proceeds to step S8.

In step S8, the image processing unit 5 arranges the first grating 2 and the second grating 3 in the horizontal direction (X direction) and arranges the dark field image 13a and the first grating 2 and the second grating 3 in the vertical direction (Y direction). direction), and the dark-field images 13b picked up are combined to generate a total scattering image 20. FIG.

Next, in step S<b>9 , the image processing unit 5 extracts the feature quantity of the internal structure (wound 14 ) of the subject T from the synthesized total scattering image 20 .

(Image generated by the image processing unit)
Next, an image generated by the image processing unit 5 according to the second embodiment will be described with reference to FIG.

ここで、Ｉ^dark _k（ｘ、ｙ）は、暗視野像１３である。また、ｋは、格子の向きを変えて撮像した複数の暗視野像１３のそれぞれを表す数である、また、Ｍは、撮像した暗視野像１３の総数（枚数）である。第２実施形態では、たとえば、Ｍ＝２である。また、ｘおよびｙは、それぞれ、画像におけるｘ方向およびｙ方向の画素の位置座標である。 10(A) and 10(B) are schematic diagrams similar to FIGS. 8(A) and 8(B), respectively, so description thereof is omitted. FIG. 10C is a schematic diagram of a total scattering image 20 obtained by synthesizing a dark-field image 13a captured with the gratings arranged horizontally (in the X direction) and a dark-field image 13b captured with the gratings arranged vertically. It is a diagram. Any method may be used as a synthesis method, but in the second embodiment, the image processing unit 5 combines the dark field image 13a shown in FIG. 10A and the dark field image 13a shown in FIG. It is configured to generate a total scattering image 20 by the image 13b and equation (4) below.

where I ^dark _k (x, y) is the dark field image 13 . Also, k is a number representing each of the plurality of dark-field images 13 captured by changing the orientation of the grating, and M is the total number (number of sheets) of the captured dark-field images 13 . In the second embodiment, for example, M=2. Also, x and y are the positional coordinates of the pixel in the x and y directions in the image, respectively.

In the total scattering image 20 shown in FIG. 10(C), an elliptical region 16 (dotted hatching) is caused by delamination of the layers in the Z direction in the subject T due to the impact on the subject T. This is the area drawn by X-ray scattering. An elliptical area 16 is an area where X-rays scattered in the vertical direction (Y direction) and the horizontal direction (X direction) due to peeling of the layers of the subject T are detected.

Other configurations of the second embodiment are the same as those of the first embodiment.

(Effect of Second Embodiment)
The following effects can be obtained in the second embodiment.

In the second embodiment, as described above, the image processing unit 5 captures a plurality of lattices arranged at a plurality of angles in a plane (XY plane) orthogonal to the optical axis direction (Z direction). It is configured to synthesize a dark field image 13 . Here, since the dark-field image 13 is imaged based on X-ray scattering in the object T, the sensitivity differs according to the orientation of the grating (some scattered rays cannot be imaged). With the configuration as described above, the total scattering image 20 generated by synthesizing the plurality of dark field images 13 in which the X-rays are scattered in a plurality of directions compensates for the difference in X-ray scattering sensitivity. A directional scatter image can be obtained. In addition, since it is possible to capture an image without changing the orientation of the subject T, the total scattering image 20 can be generated without adjusting the position of the subject T. FIG. As a result, the total scattering image 20 can be easily and accurately generated.

Further, in the second embodiment, as described above, the image processing unit 5 acquires the feature amount of the subject T from the image (total scattering image 20) generated by synthesizing the plurality of dark field images 13. It is configured. As a result, accurate synthesis can be performed without alignment, and feature amounts can be obtained easily and with high accuracy.

Further, in the second embodiment, as described above, the image processing unit 5 is configured to acquire information about the internal structure (wound 14) having directivity in the subject T as the feature amount of the subject T. Information about the internal structure (wound 14) with directivity in the subject T includes at least the length L of the blemish 14a and the width W of the blemish 14d. Thereby, for example, the shape of the directional internal structure (flaw 14) such as the internal structure (flaw 14) of carbon fiber reinforced plastic (CFRP) can be grasped in more detail.

[Third Embodiment]
Next, an X-ray imaging apparatus 300 (see FIG. 1) according to the third embodiment will be described with reference to FIGS. 1 and 11 to 14. FIG. Unlike the second embodiment in which the total scattered image 20 of the subject T is generated, in the third embodiment, the image processing unit 5 (see FIG. 1) uses a plurality of dark field images 13 with a plurality of gratings having different angles. a scattering directivity image 22 (see FIG. 13) representing the directivity of X-ray scattering by the subject T, and a directivity intensity image 23 (see FIG. 14) representing the strength of the directivity of X-ray scattering by the subject T. is configured to further generate at least one of The scattering directivity image 22 is an image obtained by imaging each internal structure of the object T based on the direction in which the X-rays are scattered by the dark field image 13 captured by changing the orientation of the grating with respect to the object T. be. The directivity intensity image 23 is an image formed based on the intensity of the directivity of scattering of X-rays of each internal structure of the subject T. FIG. Also, the same reference numerals are assigned to the same configurations as those of the first and second embodiments, and the description thereof is omitted.

(Configuration of X-ray imaging device)
First, the configuration of an X-ray imaging apparatus 300 according to the third embodiment will be described with reference to FIG.

In the third embodiment, the image processing unit 5 uses a plurality of dark-field images 13 having a plurality of gratings with different angles to obtain a scattering directivity image 22 representing the directivity of X-ray scattering by the subject T, and It is configured to generate at least one of a directivity intensity image 23 representing the intensity of X-ray scattering directivity. Specifically, the image processing unit 5 generates a scattering directivity image 22 based on a plurality of dark field images 13 (see FIG. 12) captured with gratings arranged at 0 degrees, 45 degrees, 90 degrees, and 135 degrees. and the directional strong/weak image 23, at least one of them is generated. The third embodiment shows an example in which both the scattering directional image 22 and the directional strong/weak image 23 are generated.

(Method of imaging subject)
Next, with reference to FIG. 11, the flow of the method for imaging the subject T in the X-ray imaging apparatus 300 according to the second embodiment will be described. It should be noted that the description of the same steps as in the first and second embodiments will be omitted.

In steps S1 to S5, S10 and S7, a plurality of dark field images 13 are generated by arranging each grating at a desired angle. After that, the process proceeds to step S11. Note that the processing of step S10 is different from the processing of step S6 in the first and second embodiments. rotate in degrees.

In step S11, the image processing unit 5 calculates the scattering orientation based on a plurality of dark-field images 13 captured with the first grating 2 and the second grating 3 arranged at 0 degrees, 45 degrees, 90 degrees, and 135 degrees. An image 22 or a directional strong/weak image 23 is generated and the process ends.

(Image generated by the image processing unit)
Next, images generated by the image processing unit 5 according to the third embodiment will be described with reference to FIGS. 12 to 14. FIG.

FIGS. 12A to 12D are schematic diagrams of dark-field images 13 captured with gratings arranged in different directions. Specifically, FIGS. 12A to 12D are dark-field images 13 captured with the gratings arranged at 0, 45, 90 and 135 degrees, respectively. Note that in the third embodiment, an example in which a fiber bundle obtained by bundling a plurality of fibers 21 is imaged as the subject T is shown. The example shown in FIG. 12 is an example of capturing an image of a subject T arranged in a circularly bent state. Since the subject T is circularly curved, there are regions within the subject T in which the fibers 21 are oriented differently with respect to the lattice. If the orientation of the fibers 21 with respect to the grating is different, the X-ray scattering sensitivity will be different, so that the appearance in the dark field image 13 will be different. The X-ray scattering sensitivity is enhanced when the X-rays are scattered in a direction substantially orthogonal to the direction in which the grating extends. In FIG. 12, among the fibers 21 in the subject T, the fibers 21 arranged in the direction in which the X-ray scattering sensitivity is high are indicated by solid lines as fibers 21a. Also, the fiber 21 arranged in the direction in which the X-ray scattering sensitivity is weakened is indicated by a broken line as a fiber 21b.

ここで、Ｓ^dark（ｘ、ｙ）は、複数の格子方向で撮影された暗視野像１３の複素平面上での中心であり、ｋは、各格子方向の識別番号に対応する。 In the third embodiment, the image processing unit 5 generates a scattering directional image 22 or a directional strong/weak image 23 based on a plurality of dark field images 13 shown in FIG. Specifically, the center on the complex plane of the dark-field image 13 captured in a plurality of grating directions is defined by the following equation (5).

Here, S ^dark (x, y) is the center on the complex plane of the dark field image 13 captured in a plurality of grating directions, and k corresponds to the identification number of each grating direction.

ここで、φ^dark（ｘ、ｙ）は、Ｘ線の散乱の指向を示す式である。式（６）は、Ｉ^dark _kをｋの関数としたときの位相情報を取得していることになり、これが散乱の指向性に対応する。また、Ｖ^dark（ｘ、ｙ）は、Ｘ線の散乱の指向性の強弱を示す式である。式（７）は、Ｉ^dark _kをｋの関数としたときの振幅を平均値で規格化しているものであり、これが指向性の強弱に対応する。なお、Ｘ線の散乱の指向とは、主としてどの方向にＸ線を散乱させるかということである。また、Ｘ線の散乱の指向性の強弱とは、Ｘ線を散乱させる方向の偏りを示しており、Ｘ線の散乱の指向性が強いほど、特定の方向にＸ線を散乱させる。また、Ｘ線の散乱の指向性が弱いほど、Ｘ線を等方に散乱させる。 The image processing unit 5 is configured to generate the scattering directional image 22 or the directional strong/weak image 23 based on the above equations (4), (5), and the following equations (6) and (7). It is

Here, φ ^dark (x, y) is an expression indicating the orientation of X-ray scattering. Equation (6) acquires phase information when I ^dark _k is a function of k, and this corresponds to scattering directivity. Also, V ^dark (x, y) is a formula indicating the intensity of X-ray scattering directivity. Equation (7) normalizes the amplitude with an average value when I ^dark _k is a function of k, and this corresponds to the intensity of directivity. The direction of X-ray scattering is mainly the direction in which the X-rays are scattered. Further, the intensity of X-ray scattering directivity indicates the bias in the X-ray scattering direction, and the stronger the X-ray scattering directivity, the more X-rays are scattered in a specific direction. Also, the weaker the X-ray scattering directivity, the more isotropically the X-rays are scattered.

Here, in the scattering directivity image 22, when the direction of scattering of X-rays is represented by differences in pixel values (shading), it is possible to understand at a glance which pixel value scatters X-rays in which direction. can be difficult. Therefore, in the third embodiment, the image processing unit 5 is configured to generate the scattering directivity image 22 in which the X-ray scattering directivity and color are displayed in association with each other. As a method of displaying the directivity and color of X-ray scattering in association with each other, for example, the directivity (0 degrees to 359 degrees) is associated with each color of a hue circle (circular representation of changes in hue). There are ways to express When the directivity is expressed in correspondence with each color on the color wheel, the user can grasp the directionality angle by analogy to the position of the corresponding color on the color wheel. In the example shown in FIG. 13, for the sake of convenience, the directivity of scattering and the type of line indicating the fiber 21 are displayed in association with each other.

That is, in FIG. 13, among the fibers 21 included in the subject T, the fibers 21 that scatter the X-rays in the vertical (90 degrees) direction are shown as fibers 21c by solid lines. Among the fibers 21 included in the subject T, the fibers 21 that scatter the X-rays in an oblique direction (45 degrees) are shown as fibers 21d by dashed lines. Among the fibers 21 included in the subject T, the fibers 21 that scatter the X-rays in the horizontal (0 degree) direction are shown as fibers 21e by dashed lines. Among the fibers 21 included in the subject T, the fibers 21 that scatter X-rays in an oblique direction (135 degrees) are shown as fibers 21f by chain double-dashed lines.

Further, in the example shown in FIG. 14 , in the directional intensity image 23 , the directional intensity is displayed in association with the type of line indicating the fiber 21 . That is, among the fibers 21 included in the subject T, the fibers 21 having strong X-ray scattering directivity are shown as fibers 21g by solid lines. Further, among the fibers 21 included in the subject T, the fibers 21 having medium X-ray scattering directivity are shown as fibers 21h by dashed lines. Among the fibers 21 included in the subject T, the fibers 21 with weak X-ray scattering directivity are shown as fibers 21i by dashed lines.

Other configurations of the third embodiment are the same as those of the first and second embodiments.

(Effect of the third embodiment)
The following effects can be obtained in the third embodiment.

In the third embodiment, as described above, the image processing unit 5 uses a plurality of dark-field images 13 having a plurality of gratings with different angles to obtain the scattering directivity images 22 representing the directivity of X-ray scattering by the subject T. and a directivity intensity image 23 representing the intensity of the directivity of the X-ray scattering by the object T is further generated. Thus, by generating the scattering directivity image 22, the scattering of X-rays by the subject T can be grasped. Further, by generating the directivity intensity image 23, the intensity of the directivity of the X-ray scattering by the subject T can be grasped. As a result, the distribution of a plurality of internal structures (fibers 21) having different scattering directivities within the subject T, the distribution of defects occurring within the subject T, and the like can be grasped in more detail.

In the third embodiment, as described above, the image processing unit 5 is configured to generate the scattering directivity image 22 in which the scattering directivity of X-rays and the colors are associated with each other and displayed. As a result, since the X-ray scattering directivity and color are associated in the scattering directivity image 22, for example, the scattering directivity image 22 in which the difference in directivity is displayed by the difference in pixel values (brightness and darkness of the image). By comparison, the directivity of X-ray scattering can be easily grasped.

Other effects of the third embodiment are the same as those of the first and second embodiments.

[Fourth embodiment]
Next, an X-ray imaging apparatus 400 (see FIG. 1) according to a fourth embodiment will be described with reference to FIGS. 1, 15 and 16. FIG. Unlike the first embodiment in which the grating rotating mechanism 7 includes the gear-shaped grating holding part 70 and the gear-shaped rotating part 71, in the fourth embodiment, the grating rotating mechanism 7 rotates with the grating holding part 70. It is composed of a belt-pulley mechanism in which the moving part 71 is connected by a belt 74 . The grid retainer 70 includes, for example, a toothed pulley. Rotating portion 71 includes, for example, a pinion. Belt 74 includes, for example, a timing belt. The same reference numerals are assigned to the same configurations as those of the first to third embodiments, and the description thereof is omitted.

(Configuration of grating rotation mechanism)
As shown in FIG. 15 , the grid rotating mechanism 7 according to the fourth embodiment includes a grid holding portion 70 , a rotating portion 71 , and a belt 74 connecting the grid holding portion 70 and the rotating portion 71 . The grating rotating mechanism 7 in the fourth embodiment is a so-called belt-pulley mechanism. In addition, in the fourth embodiment, as shown in FIG. 15, the grating rotation mechanism 7 further includes a stopper mechanism 75 that switches the grating between a rotatable state and an unrotatable state. The lattice holding portion 70 , the rotating portion 71 , the belt 74 and the stopper mechanism 75 are each provided inside the housing 72 .

The stopper mechanism 75 includes an abutting member 75a that abuts against the grid holding portion 70, an urging member 75b (see FIG. 16) that urges the abutting member 75a against the grid holding portion 70, and an urging force. and a contact release portion 75c that separates the contact member 75a from the lattice holding portion 70. As shown in FIG. The contact member 75a includes, for example, a brake pad such as rubber. The contact member 75a and the contact state releasing portion 75c are connected via the first intermediate member 75d. The abutment member 75a is configured to make the lattice holding portion 70 unrotatable by coming into contact with the lattice holding portion 70 . The abutment member 75a is configured to be rotatable around the axis in the Z direction integrally with the first intermediate member 75d around the central axis 75e.

The biasing member 75b biases the contact member 75a in the X2 direction. Specifically, one end of the biasing member 75b is connected to the second intermediate member 75f on the Z2 side of the lattice rotation mechanism 7 . Also, the other end side of the biasing member 75b is fixed to the housing 72 . The second intermediate member 75f is connected to the contact member 75a via a central shaft 75e. The urging member 75b urges the tension F in the X2 direction to the second intermediate member 75f to bring the abutment member 75a into contact with the grid holding portion . The biasing member 75b includes, for example, a coil spring. Further, the contact state release portion 75c is configured to apply a force in the Y2 direction to the first intermediate member 75d when power is supplied by the control portion 6 (see FIG. 1). The contact state releasing portion 75c includes, for example, a solenoid. The force applied by the contact release portion 75c to the contact member 75a via the first intermediate member 75d is set to be greater than the tension force F applied to the contact member 75a by the biasing member 75b. be done.

(Switching the Rotating State of the Lattice by the Stopper Mechanism)
In the fourth embodiment, the stopper mechanism 75 is configured to switch between a state in which the lattice can be rotated and a state in which the lattice cannot be rotated under the control of the controller 6 . Specifically, under the control of the control unit 6, the stopper mechanism 75 causes the contact member 75a to contact the grid holding unit 70 by the contact state canceling unit 75c, and the contact member 75a to the grid holding unit 70. It is configured to switch between the spaced state.

The biasing member 75b always biases the contact member 75a with tension F in the X2 direction. The contact state releasing portion 75c does not apply force in the Y2 direction to the first intermediate member 75d when power is not supplied by the control portion 6 . Therefore, when the contact release portion 75c is not energized, only the tension F from the biasing member 75b is applied to the contact member 75a. This state is a state in which the lattice cannot be rotated. When the grid cannot be rotated, the contact member 75a is biased in the X2 direction by the biasing member 75b, so that it is in contact with the grid holding portion . Therefore, the grating holding part 70 cannot rotate.

On the other hand, when the contact state releasing portion 75c is energized by the control portion 6, the contact state releasing portion 75c applies a force in the Y2 direction to the first intermediate member 75d, thereby releasing the contact member 75a. It is set in a state separated from the lattice holding part 70 . This state is a state in which the lattice can be rotated. When it is desired to change the orientation of the grid with respect to the subject T, the control section 6 energizes the contact state canceling section 75c to separate the contact member 75a, thereby making the grid holding section 70 rotatable. do. As described above, the stopper mechanism 75 is configured to switch between the state in which the grid can be rotated and the state in which the grid cannot be rotated.

In addition, as shown in FIG. 15, in the fourth embodiment, the grid rotation mechanism 7 includes an origin position detector 76 that detects the grid origin position. The origin position detection portion 76 is configured to detect the position of the detected portion 77 provided in the grating holding portion 70 . Origin position detector 76 includes, for example, a photosensor. In the example shown in FIG. 15, the origin position detection portion 76 is provided on a line 80 extending in the Y2 direction from the center of the lattice holding portion 70 . In the fourth embodiment, the controller 6 is configured to store the position at which the detected portion 77 is detected by the origin position detector 76 as the origin position of the lattice in the storage (not shown).

Other configurations of the fourth embodiment are the same as those of the first to third embodiments.

(Effect of the fourth embodiment)
The following effects can be obtained in the fourth embodiment.

In the fourth embodiment, as described above, the grating rotation mechanism 7 further includes the stopper mechanism 75 that switches the grating between the rotatable state and the non-rotatable state. As a result, unintended rotation of the grid such as malfunction of the rotating portion 71 can be suppressed by keeping the grid in a non-rotatable state when the subject T is imaged. As a result, it is possible to suppress the occurrence of unintended positional deviation in the rotation direction of the grating about the optical axis after the orientation of the grating is changed by the grating rotating mechanism 7 and before the imaging is performed.

Further, in the fourth embodiment, as described above, the stopper mechanism 75 includes the contact member 75a that contacts the grid holding portion 70 and the biasing member 75b that biases the contact member 75a against the grid holding portion 70. and a contact release portion 75c that separates the contact member 75a from the lattice holding portion 70 against the biasing force of the biasing member 75b. Accordingly, by operating the contact state release portion 75c, the grid can be switched from a state in which the grid cannot be rotated due to the biasing force of the biasing member 75b to a state in which the grid can be rotated. As a result, it is possible to make the grating rotatable only when the orientation of the grating is to be changed, so that the rotational displacement of the grating can be suppressed as much as possible with a simple configuration.

In addition, in the fourth embodiment, as described above, the grating rotation mechanism 7 further includes the origin position detector 76 that detects the origin position of the grating. As a result, when rotating each grid, it is possible to easily confirm whether each grid is arranged at the origin position. As a result, when rotating each grid, each grid can be easily arranged in the initial position.

Other effects of the fourth embodiment are the same as those of the first embodiment.

Next, an X-ray imaging apparatus 500 according to a fifth embodiment will be described with reference to FIGS. 17 and 18. FIG. Unlike the first embodiment that generates the two-dimensional dark field image 13 of the subject T, in the fifth embodiment, the X-ray imaging apparatus 500 is composed of the X-ray source 1, the detector 4 and a plurality of gratings. The image processing unit 5 further includes a rotation mechanism 18 that relatively rotates the imaging system 17 and the subject T, and the image processing unit 5 generates a plurality of dark field images 13 captured at a plurality of rotation angles while relatively rotating the subject T and the imaging system 17. to generate a three-dimensional dark field image. In addition, the same code|symbol is attached|subjected about the structure similar to the said 1st Embodiment, and description is abbreviate|omitted.

(Configuration of X-ray imaging device)
First, referring to FIG. 17, the configuration of an X-ray imaging apparatus 500 according to the fifth embodiment will be described.

As shown in FIG. 17, an X-ray imaging apparatus 500 according to the fifth embodiment includes a rotation mechanism 18 that relatively rotates an imaging system 17 composed of an X-ray source 1, a detector 4, and a plurality of gratings and a subject T. further provide. Specifically, the rotation mechanism 18 is configured to relatively rotate the subject T and the imaging system 17 by rotating the subject T around the rotation axis AR. The rotating mechanism 18 is, for example, a rotatable subject stage on which the subject T is placed, and includes a motor and the like.

(Method of imaging subject)
Next, with reference to FIG. 18, the flow of the method for imaging the subject T in the X-ray imaging apparatus 500 according to the fifth embodiment will be described. It should be noted that the description of steps that are the same as in the first embodiment will be omitted.

In the fifth embodiment, the image processing unit 5 generates a three-dimensional dark field image from a plurality of dark field images 13 captured at a plurality of rotation angles while relatively rotating the subject T and the imaging system 17. It is configured.

Specifically, in steps S<b>1 and S<b>2 , the first grating 2 and the second grating 3 are arranged sideways (in the X direction), and the subject T is arranged on the rotation mechanism 18 . After that, the process proceeds to step S12.

In step S12, the control unit 60 rotates the subject T via the rotation mechanism 18 to relatively rotate the subject T and the imaging system 17, while translating the first grating 2 at a plurality of rotation angles to capture an image. By doing so, a plurality of dark field images 13 are captured. After that, the process proceeds to step S13. In this specification, the technique of translating the first grating 2 while rotating the subject T is referred to as phase CT imaging.

In step S13, the image processing unit 5 generates a three-dimensional dark field image from a plurality of dark field images 13 captured at a plurality of rotation angles while rotating the subject T and the imaging system 17 relative to each other.

After that, in step S5, it is determined whether or not the image has been captured by changing the orientation of the lattice. If the orientation of the lattice is changed and the image is captured, the process is terminated. If the orientation of the grating has not been changed and the image has not been captured, the process proceeds to step S6.

Other configurations of the fifth embodiment are the same as those of the first to fourth embodiments.

(Effect of the fifth embodiment)
The following effects can be obtained in the fifth embodiment.

In the fifth embodiment, as described above, the rotation mechanism 18 for relatively rotating the imaging system 17 configured by the X-ray source 1, the detector 4, and the plurality of gratings and the subject T is further provided. is configured to generate a three-dimensional dark-field image from a plurality of dark-field images 13 captured at a plurality of rotation angles while the subject T and the imaging system 17 are relatively rotated. Here, since the direction of X-ray scattering that is emphasized also differs depending on the direction of the rotation axis AR and the orientation of the grating when performing relative rotation between the object T and the imaging system 17, the relative direction between the object T and the imaging system 17 is There are cases where it is desired to change the direction of the rotation axis AR when rotating. Moreover, there are cases where it is desired to change the orientation of the subject T with respect to the rotation axis AR when the subject T and the imaging system 17 are relatively rotated. By performing the phase CT imaging as described above, without changing the direction of the rotation axis AR when performing relative rotation between the subject T and the imaging system 17, the orientation of the subject T with respect to the grid is changed. A dimensional dark field image can be generated. Further, it is possible to generate a three-dimensional dark-field image captured by changing the orientation of the subject T with respect to the grid without changing the orientation of the subject T. As a result, there is no need to combine a mechanism for changing the direction of the rotation axis AR and a mechanism for changing the orientation of the subject T when performing relative rotation between the subject T and the imaging system 17, so the device configuration is complicated. can be suppressed.

Other effects of the fifth embodiment are the same as those of the first to fourth embodiments.

(Modification)
It should be noted that the embodiments disclosed this time should be considered as examples and not restrictive in all respects. The scope of the present invention is indicated by the scope of the claims rather than the above description of the embodiments, and includes all modifications (modifications) within the meaning and scope equivalent to the scope of the claims.

For example, in the above first to fifth embodiments, the grid moving mechanism 8 translates the first grid 2, but the present invention is not limited to this. The grid to be translated may be any grid.

Further, in the above-described first to fifth embodiments, the grid position adjustment mechanism 9 has shown an example of adjusting the positional deviation of the first grid 2, but the present invention is not limited to this. Any grid may be used to adjust the positional deviation.

Further, in the above-described first to fifth embodiments, an example in which the grid position adjusting mechanism 9 is arranged above the grid moving mechanism 8 has been shown, but the present invention is not limited to this. The grid moving mechanism 8 and grid position adjusting mechanism 9 may be arranged under separate grids.

Further, in the above-described first to fifth embodiments, an example in which the first grating 2 and the second grating 3 are provided as the plurality of gratings has been shown, but the present invention is not limited to this. For example, as in an X-ray imaging apparatus 400 shown in FIG. 13, a configuration in which a third grating 19 is provided between the X-ray source 1 and the first grating 2 may be employed. The third grating 19 has a plurality of slits 19a and X-ray absorbing portions 19b arranged at a predetermined period (pitch) d4 in the Y direction. Each slit 19a and X-ray absorbing portion 19b are formed to extend linearly. Moreover, each slit 19a and the X-ray absorbing portion 19b are formed so as to extend in parallel. The third grating 19 is arranged between the X-ray source 1 and the first grating 2 and is irradiated with X-rays from the X-ray source 1 . The third grating 19 is configured to turn the X-rays passing through each slit 19a into a line light source corresponding to the position of each slit 19a. In addition, in the configuration in which the third grating 19 is provided, the grating rotation mechanism 7 that rotatably holds the third grating 19 is provided, and the third grating 19 is rotated by the signal from the control unit 6. The first grating 2 and the second grating 3 are arranged at substantially the same rotation angle θ through the . Thereby, the third grating 19 can enhance the coherence of X-rays emitted from the X-ray source 1 . As a result, the self-image 12 of the first grating 2 can be formed without depending on the focal size of the X-ray source 1, so the degree of freedom in selecting the X-ray source 1 can be improved.

Further, in the case where the third grating 19 is further provided, the relative position between any one of the plurality of gratings is adjusted so that the second grating 3 and the third grating 19 become the first grating. It is configured to be arranged in relative and symmetrical relative positions with reference to the grating 2 . That is, when the grids are arranged such that the distance between the third grid 19 and the first grid 2 and the distance between the first grid 2 and the second grid 3 are equal, the third grid 19 is rotated by an angle θ with respect to the horizontal direction (X direction) perpendicular to the X-ray optical axis direction (Z direction) in the XY plane, the second grating 3 is arranged in the XY plane In the detector 4, if it is rotated in the opposite direction (minus direction) by an angle θ with respect to the horizontal direction (X direction) perpendicular to the optical axis direction (Z direction) of the X-ray, , the moire fringes 11 disappear, so it can be considered that the position adjustment has been completed. With the above configuration, any one of the first grating 2, the second grating 3, and the third grating 19 is placed at a relative and symmetrical relative position with respect to the first grating 2. By doing so, it becomes possible to adjust the positions of the plurality of grids, so that the relative positions between the plurality of grids can be easily adjusted.

In addition, in the first, second, fourth and fifth embodiments, the examples in which the gratings are oriented at approximately 90 degrees and approximately 0 degrees are shown as examples of the vertical direction (Y direction) and horizontal direction (X direction). However, the present invention is not limited to this. The gratings may be arranged in directions other than approximately 90 degrees and approximately 0 degrees, as long as they are two directions that are substantially perpendicular to each other. For example, the gratings may be oriented at 30 degrees and 120 degrees. Moreover, the gratings may be arranged at any angle as long as the directions of the gratings are different from each other. good. However, if the angles are close to each other, there is a possibility that the X-ray scattering may not be emphasized, so it is preferable to arrange the gratings in directions including at least two substantially orthogonal directions for imaging.

Also, in the fifth embodiment, an example in which the subject T is rotated was shown, but the present invention is not limited to this. A configuration in which the imaging system 17 is rotated may be used.

Further, in the above-described first to fifth embodiments, an example in which the dark-field image 13 is generated by translating the first grating 2 has been shown, but the present invention is not limited to this. for example. The dark-field image 13 may be generated by a moiré single-shot technique in which any one of a plurality of gratings is rotated within the XY plane to form moiré fringes 11 and an image is captured.

Further, in the above-described first to fifth embodiments, an example of using a phase grating as the first grating 2 has been shown, but the present invention is not limited to this. For example, an absorption grating may be used as the first grating 2 .

Also, in the first, second, fourth, and fifth embodiments, an example in which carbon fiber reinforced plastic (CFRP) is imaged as the subject T has been described, but the present invention is not limited to this. For example, glass fiber reinforced plastic (GFRP) or the like may be used as the subject. Any object can be used as long as the object to be imaged contains an internal structure with directivity.

Further, in the above-described first to fifth embodiments, an example in which the subject T is arranged between the X-ray source 1 and the first grating 2 has been shown, but the present invention is not limited to this. The object T may be arranged between the first grating 2 and the second grating 3 . In any case, if the object T is placed at a position distant from the first grating 2, the phase sensitivity is lowered.

Further, in the above-described fourth embodiment, an example in which each of the lattice rotating mechanisms 7 is provided with the rotating portion 71 was shown, but the present invention is not limited to this. For example, a plurality of lattice rotating mechanisms 7 for rotating each lattice may be configured to be rotated by one rotating portion 71 .

Further, in the above-described third embodiment, an example in which the image processing unit 5 generates both the scattering directional image 22 and the directional intensity image 23 has been described, but the present invention is not limited to this. For example, the image processing unit 5 may be configured to generate either the scattering directional image 22 or the directional intensity image 23 . Further, the image processing unit 5 may be configured to generate a combined image by combining the total scattering image 20 generated in the second embodiment, the scattering directional image 22, and the directional intensity image 23. good.

Further, in the above-described fourth embodiment, an example is shown in which the grating rotation mechanism 7, which is a belt-pulley mechanism, includes the stopper mechanism 75, but the present invention is not limited to this. For example, as shown in the first embodiment, in the configuration in which the lattice rotation mechanism 7 includes the gear-shaped lattice holding portion 70 and the gear-shaped rotation portion 71, the stopper mechanism 75 may be provided. .

ここで、θは、格子の角度である。また、φは、Ｉ^dark _kをｋの関数としたときの位相情報である。画像処理部５は、上記式（８）の位相情報φからφ^dark（ｘ、ｙ）を、Ｂ／ＡからＶ^dark（ｘ、ｙ）を算出することにより、散乱指向像２２および指向性強弱像２３を取得するように構成されていてもよい。またｋ（格子方向）は４方向に限定されるわけではない。格子を配置する方向は２方向であってもよい。しかし、格子を配置する方向が２方向である場合、被写体ＴによるＸ線の散乱の方向によっては、感度よく検出することが難しい場合があるので、格子を配置する方向は、３方向以上であることが好ましい。またｋは等間隔である必要もないが、その場合は上記式（８）のようなサインカーブのフィッティング方法で散乱指向像２２や指向性強弱像２３を算出することが好ましい。 Further, in the above-described third embodiment, an example of a configuration in which the image processing unit 5 acquires the scattering directional image 22 and the directional intensity image 23 by the above equation (6) and the above equation (7) is shown. The invention is not limited to this. For example, the image processing unit 5 may be configured to obtain the scattering directional image 22 and the directional intensity image 23 by fitting I ^dark _k with a sine curve (sine wave) as a function of k. . Specifically, it is assumed that the dark field image 13 is a sine wave as shown in Equation (8) below.

where θ is the grating angle. Also, φ is phase information when I ^dark _k is a function of k. The image processing unit 5 calculates φ ^dark (x, y) from the phase information φ in the above equation (8) and V ^dark (x, y) from B/A, thereby obtaining the scattering directivity image 22 and directivity intensity. It may be arranged to acquire an image 23 . Also, k (lattice direction) is not limited to four directions. The grid may be arranged in two directions. However, when the gratings are arranged in two directions, it may be difficult to detect the X-rays with high sensitivity depending on the direction of scattering of the X-rays by the subject T. Therefore, the gratings are arranged in three or more directions. is preferred. In addition, k does not have to be evenly spaced, but in that case, it is preferable to calculate the scattering directivity image 22 and the directivity intensity image 23 by a sine curve fitting method such as the above equation (8).

Reference Signs List 1 X-ray source 2 first grating 3 second grating 4 detector 5 image processing unit 6 control unit 7 grating rotating mechanism 8 grating moving mechanism 9 grating position adjusting mechanism 10 grating angle information storage unit 11 moire fringes 12 self-image 13, 13a, 13b, 13c Dark-field image 14 Scratches inside the subject (internal structure with directivity)
14a laterally extending wound (directional internal structure)
14b, 14c Scratches extending diagonally (directional internal structure)
14d Longitudinal wound (directional internal structure)
17 Imaging System 18 Rotation Mechanism 19 Third Grating 20 Total Scattering Image 22 Scattering Directional Image 23 Directional Intensity Image 70 Grating Holding Section 75 Stopper Mechanism 75a Contact Member 75b Biasing Member 75c Contact Release Section 100, 200, 300, 400 X-ray imaging device L Length of wound extending laterally (length of directional internal structure)
T Subject W Width of scratch extending in vertical direction (width of internal structure with directivity)

Claims (18)

an x-ray source;
a plurality of gratings including a first grating for forming a self-image with X-rays emitted from the X-ray source and a second grating for interfering with the self-image of the first grating;
a detector that detects X-rays emitted from the X-ray source;
a plurality of grating rotating mechanisms provided in each of the plurality of gratings and individually rotating the plurality of gratings in a plane orthogonal to the optical axis direction of X-rays;
an image processing unit that generates at least a dark field image from the X-ray intensity distribution detected by the detector ;
a grid moving mechanism for moving at least one of the plurality of grids ;
The image processing unit is configured to generate the dark field image captured by arranging the grating at a plurality of angles in a plane orthogonal to the optical axis direction ,
The grating moving mechanism is configured to move the grating vertically or horizontally in a plane orthogonal to the optical axis direction, and at least one of the plurality of gratings is arranged obliquely. any one of the plurality of gratings is moved in the vertical direction or the horizontal direction in which the distance of translational movement becomes smaller, according to the arrangement angle of the plurality of gratings . , X-ray imaging equipment. The grating rotation mechanism is configured to arrange the plurality of gratings in at least two directions of a vertical direction, a horizontal direction, and an oblique direction within a plane orthogonal to the optical axis direction. Item 1. The X-ray imaging apparatus according to item 1. 3. The lattice moving mechanism according to claim 1 or 2, wherein after rotating the plurality of lattices, the lattice moving mechanism moves at least one of the plurality of lattices together with the lattice rotating mechanism. An X-ray imaging device as described. The grating moving mechanism moves any one of the plurality of gratings in a direction in which the distance of the translational movement becomes smaller when any one of the plurality of gratings is translated by at least one period of the grating. 4. The X-ray imaging apparatus of claim 3, configured to: 5. The X-ray imaging apparatus according to any one of claims 1 to 4, wherein said grating rotating mechanism includes a grating holding part that holds a grating and a rotating part that rotates said grating holding part. 6. The X-ray imaging apparatus according to claim 5, wherein the grating rotating mechanism further includes a stopper mechanism for switching between a state in which the grating can be rotated and a state in which the grating cannot be rotated. The stopper mechanism includes an abutting member that abuts against the grid holding portion, a biasing member that biases the abutting member against the grid holding portion, and a biasing member that resists the biasing force of the biasing member. 7. The X-ray imaging apparatus according to claim 6, further comprising a contact state releasing portion that separates the contact member from the grating holding portion. The X-ray imaging apparatus according to any one of claims 5 to 7, wherein said grating rotation mechanism further comprises an origin position detection section for detecting an origin position of the grating. further comprising a grating angle fine adjustment mechanism provided separately from the grating rotation mechanism for finely adjusting the angular deviation of the plurality of gratings in the rotation direction around the X-ray irradiation axis;
5. The X-ray imaging apparatus according to claim 3, wherein said grating rotating mechanism is configured to be held on said grating moving mechanism via said grating angle fine adjustment mechanism. 10. The X-ray according to claim 9, further comprising a control unit that calculates an adjustment amount of the grating by the grating angle fine adjustment mechanism based on moire fringes generated after the plurality of gratings are rotated by the grating rotation mechanism. imaging device. 11. The X-ray imaging apparatus according to any one of claims 1 to 10, further comprising a grating angle information storage section for storing angle information of said plurality of gratings rotated by said grating rotating mechanism. An imaging system configured by the X-ray source, the detector, and the plurality of gratings, and a rotation mechanism for relatively rotating the subject,
The image processing unit is configured to generate a three-dimensional dark field image from a plurality of the dark field images captured at a plurality of rotation angles while relatively rotating the subject and the imaging system. The X-ray imaging apparatus according to any one of 1 to 11. an x-ray source;
a plurality of gratings including a first grating for forming a self-image with X-rays emitted from the X-ray source and a second grating for interfering with the self-image of the first grating;
a detector that detects X-rays emitted from the X-ray source;
a grating rotating mechanism for rotating each of the plurality of gratings in a plane orthogonal to the optical axis direction of X-rays;
an image processing unit that generates at least a dark field image from the X-ray intensity distribution detected by the detector;
The image processing unit is configured to generate the dark field image captured by arranging the grating at a plurality of angles in a plane orthogonal to the optical axis direction,
The image processing unit synthesizes a plurality of dark-field images captured with the grating arranged at a plurality of angles in a plane orthogonal to the optical axis direction, and calculates the intensity of X-ray scattering by the subject. configured to generate a total scatter image representing
The image processing unit uses a plurality of dark field images in which the angles of the plurality of gratings are different, a scattering directivity image representing the directivity of X-ray scattering by the subject, and a directivity of X-ray scattering by the subject. An X-ray imaging apparatus configured to further generate at least one of a directional intensity image representing intensity and a weak/weak image. 14. The X-ray imaging apparatus according to claim 13 , wherein said image processing unit is configured to generate said scattering directivity image in which X-ray scattering directivity and color are associated and displayed. The X according to any one of claims 1 to 14, wherein the image processing unit is configured to acquire a feature amount of the subject from an image generated by synthesizing a plurality of the dark field images. Line imaging device. The image processing unit is configured to acquire information about an internal structure having directivity in the subject as the feature amount of the subject,
16. The X-ray imaging apparatus according to claim 15 , wherein the information about the internal structure with directivity in the object includes at least the length of the internal structure with directivity and the width of the internal structure with directivity. . The X - ray imaging apparatus of any one of claims 1-16, wherein the plurality of gratings further includes a third grating positioned between the X-ray source and the first grating. In the plurality of gratings, the relative position between any one of the plurality of gratings is adjusted so that the second grating and the third grating are relatively and symmetrically with respect to the first grating. 18. The X-ray imaging apparatus according to claim 17 , wherein the X-ray imaging apparatus is configured to be arranged in different relative positions.

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