X-ray phase imaging device and x-ray phase imaging analysis method

Abstract

This X-ray phase imaging device (100) comprises: an X-ray light source (10), an X-ray detector (11), a plurality of lattices; a rotary mechanism (15) which rotates a subject (90) including fibers (91a) and the plurality of lattices relative to each other; an image processing unit (2a) which generates a plurality of X-ray phase contrast images (40) for each of the orientations of the subject with respect to the plurality of lattices; and a control unit (2b) which acquires orientation information (30) pertaining to the orientations of fibers included in the subject on the basis of the plurality of X-ray phase contrast images, and acquires a feature amount (31) pertaining to the mechanical strength of the subject.

Description

X-ray phase imaging device and X-ray phase imaging image analysis method

[0001] The present invention relates to an X-ray phase imaging apparatus and an X-ray phase imaging image analysis method, and more particularly to an X-ray phase imaging apparatus and an X-ray phase imaging image analysis method that image an object while rotating the object and a plurality of gratings relative to each other.

[0002] An X-ray phase-shift imaging apparatus is known that captures an image of an object while rotating the object and a plurality of gratings relative to each other. Such an X-ray phase-shift imaging apparatus is disclosed in, for example, Japanese Patent No. 6943090.

[0003] Japanese Patent No. 6943090 discloses an X-ray imaging device including an X-ray source, multiple gratings including a first grating and a second grating, a detector, an image processing unit, a control unit, and a direction change mechanism. The configuration disclosed in Japanese Patent No. 6943090 rotates the object and the multiple gratings relative to each other using the direction change mechanism, changing the orientation of the object relative to the multiple gratings and generating multiple dark-field images corresponding to the orientation of the object. Furthermore, Japanese Patent No. 6943090 discloses an X-ray imaging device configured to image a carbon fiber reinforced plastic (CFRP) object. Japanese Patent No. 6943090 also discloses a configuration for extracting fibers extending in different directions contained in the object based on the generated dark-field images.

[0004] Patent No. 6943090

[0005] It is known that CFRP containing carbon fibers has high mechanical strength against forces acting in the direction of fiber extension and low mechanical strength against forces acting in a direction intersecting the fiber extension direction. However, while an X-ray phase-shift imaging device such as that disclosed in Japanese Patent No. 6943090 can acquire the fiber extension direction (orientation information), it is difficult for a user to identify areas where mechanical strength is reduced due to fiber orientation. Therefore, there is a need for an X-ray phase-shift imaging device that can easily identify areas in a subject where mechanical strength is reduced due to fiber orientation.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide an X-ray phase imaging device and an X-ray phase imaging image analysis method that can easily identify areas in a subject where mechanical strength has decreased due to fiber orientation.

[0007] In order to achieve the above-mentioned object, an X-ray phase imaging device in a first aspect of the present invention is an X-ray phase imaging device that predicts locations where the mechanical strength of a subject containing fibers is reduced, and includes an X-ray source that irradiates X-rays, an X-ray detector that detects the X-rays irradiated from the X-ray source, a plurality of gratings arranged between the X-ray source and the X-ray detector, a rotation mechanism that rotates the subject and the plurality of gratings relatively in a rotational direction about the X-ray irradiation axis, an image processing unit that rotates the subject and the plurality of gratings relatively using the rotation mechanism and changes the orientation of the subject relative to the plurality of gratings while capturing images, thereby generating a plurality of X-ray phase contrast images for each orientation of the subject relative to the plurality of gratings based on the X-ray intensity distribution detected by the X-ray detector, and a control unit that acquires orientation information regarding the orientation of fibers contained in the subject based on the plurality of X-ray phase contrast images, and acquires feature quantities related to the mechanical strength of the subject based on the acquired orientation information.

[0008] In addition, an X-ray phase imaging image analysis method in a second aspect of the present invention is an X-ray phase imaging image analysis method for predicting locations where the mechanical strength of a subject containing fibers is reduced, and includes the steps of: imaging the subject and a plurality of gratings arranged between an X-ray source and an X-ray detector at a plurality of imaging angles while rotating them relatively in a rotational direction around the X-ray irradiation axis direction; generating a plurality of X-ray phase contrast images for each orientation of the subject relative to the plurality of gratings based on the X-ray intensity distribution detected by the X-ray detector; acquiring orientation information regarding the orientation of fibers contained in the subject based on the plurality of X-ray phase contrast images; and acquiring features related to the mechanical strength of the subject based on the acquired orientation information.

[0009] In the X-ray phase-contrast imaging apparatus according to the first aspect and the X-ray phase-contrast imaging image analysis method according to the second aspect, as described above, a feature quantity related to the mechanical strength of the object is acquired based on orientation information related to the orientation of fibers contained in the object. This allows a user to confirm the feature quantity related to the mechanical strength of the object acquired based on the orientation information. As a result, it is possible to easily identify areas in the object where mechanical strength is reduced due to fiber orientation.

[0010] FIG. 1 is a schematic diagram showing the overall configuration of an X-ray phase imaging apparatus according to an embodiment. FIG. 1 is a schematic diagram for explaining the configuration of an X-ray imaging unit according to an embodiment. FIG. 2 is a schematic diagram for explaining the configuration of a rotation mechanism of an X-ray phase imaging apparatus according to an embodiment. FIG. 3 is a schematic diagram for explaining the configuration of a grating position adjustment mechanism of an X-ray phase imaging apparatus according to an embodiment. FIG. 4 is a schematic diagram for explaining a configuration for generating an X-ray phase contrast image. FIG. 5 is a schematic diagram for explaining an absorption image, a differential phase image, and a dark-field image generated by an X-ray phase imaging apparatus according to an embodiment. FIG. 6 is a schematic diagram for explaining the structure of an object. FIG. 7 is a schematic diagram for explaining imaging of an object divided into multiple test pieces. FIG. 8 is a schematic diagram for explaining a configuration for acquiring orientation information from a dark-field image. FIG. 9 is a graph for explaining a configuration for acquiring orientation information from a dark-field image. FIG. 10 is a schematic diagram for explaining an orientation analysis image. FIG. 11 is a schematic diagram for explaining a tensor image generated from an orientation analysis image. FIG. 12 is a schematic diagram for explaining a binarized image generated by an image processing unit according to an embodiment. FIG. 13 is a diagram for explaining feature amounts acquired by a control unit according to an embodiment, and a fracture position when a tensile test is performed. 1 is a graph showing the relationship between the position of the maximum binarized region and the fracture position when a tensile test is performed. FIG. 2 is a graph showing the relationship between maximum stress and total area ratio. FIG. 3 is a schematic diagram (A) and a schematic diagram (B) for explaining the tendency of fiber orientation bias. FIG. 4 is a schematic diagram for explaining a configuration in which an X-ray phase imaging device according to an embodiment displays a dark-field image, a binarized image, and feature amounts. FIG. 5 is a flowchart for explaining a process in which an X-ray phase imaging device according to an embodiment displays feature amounts. FIG. 6 is a schematic diagram showing the overall configuration of an X-ray phase imaging device according to a modified example. FIG. 7 is a schematic diagram for explaining the configuration of an X-ray imaging unit according to a modified example. FIG. 8 is a schematic diagram for explaining the distribution in the thickness direction of a specific directional fiber region using an image captured by an X-ray phase imaging device according to a modified example.

[0011] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described with reference to the accompanying drawings.

[0012] First, with reference to FIG. 1, the overall configuration of an X-ray phase imaging apparatus 100 according to an embodiment of the present invention will be described.

[0013] As shown in FIG. 1, the X-ray phase imaging apparatus 100 is an apparatus that uses the Talbot effect to image the inside of an object 90 (see FIG. 2). The object 90 is, for example, a fiber composite material including fibers 91a (see FIG. 7). The object 90 is, for example, carbon fiber reinforced plastic (CFRP). In this embodiment, the X-ray phase imaging apparatus 100 is configured to predict locations where the mechanical strength of the object 90 including the fibers 91a is reduced.

[0014] The X-ray phase imaging apparatus 100 includes an X-ray imaging unit 1 and a computer 2. The X-ray phase imaging apparatus 100 also includes a display unit 3 and an input receiving unit 4.

[0015] The X-ray imaging unit 1 includes an X-ray source 10, a plurality of gratings, an X-ray detector 11, a rotation mechanism 15, and a grating position adjustment mechanism 16. The plurality of gratings include a first grating 12, a second grating 13, and a third grating 14. Details of the X-ray imaging unit 1, such as the arrangement of the X-ray source 10, the plurality of gratings, and the X-ray detector 11, will be described later.

[0016] The computer 2 includes an image processing unit 2a, a control unit 2b, memories such as a ROM (Read Only Memory) and a RAM (Random Access Memory), and a storage unit 2c. The image processing unit 2a is configured, for example, by a GPU (Graphics Processing Unit) or an FPGA (Field-Programmable Gate Array) configured for image processing, circuitry, etc. The control unit 2b is configured by a CPU (Central Processing Unit), a GPU or an FPGA configured for image processing, circuitry, etc.

[0017] The image processing unit 2a is configured to rotate the subject 90 and the multiple gratings relative to each other using the rotation mechanism 15, change the orientation of the subject 90 with respect to the multiple gratings, and capture images while changing the orientation of the subject 90 with respect to the multiple gratings, thereby generating multiple X-ray phase contrast images 40 for each orientation of the subject 90 with respect to the multiple gratings, based on the X-ray intensity distribution detected by the X-ray detector 11. The image processing unit 2a is also configured to generate a tensor image 42 (see FIG. 12 ), which will be described later. Details of the configuration by which the image processing unit 2a generates the X-ray phase contrast image 40 and the tensor image 42 will be described later. The tensor image 42 is an example of an "orientation information image" in the claims.

[0018] The control unit 2b is configured to control the X-ray source 10, the rotation mechanism 15, the lattice position adjustment mechanism 16, etc. The control unit 2b also includes an orientation information acquisition unit 20, a feature amount acquisition unit 21, and an intensity decrease portion prediction unit 22. The orientation information acquisition unit 20, the feature amount acquisition unit 21, and the intensity decrease portion prediction unit 22 are configured in software as functional blocks realized by the control unit 2b executing various programs. The orientation information acquisition unit 20, the feature amount acquisition unit 21, and the intensity decrease portion prediction unit 22 may also be configured in hardware by providing a dedicated processor (processing circuit).

[0019] The orientation information acquisition unit 20 acquires orientation information 30 relating to the orientation of fibers 91a (see FIG. 7) included in the subject 90 based on the multiple X-ray phase contrast images 40. Details of the configuration by which the orientation information acquisition unit 20 acquires the orientation information 30 will be described later.

[0020] The feature amount acquiring unit 21 is configured to acquire feature amounts 31 related to the mechanical strength of the subject 90 based on the orientation information 30 acquired by the orientation information acquiring unit 20. Details of the configuration by which the feature amount acquiring unit 21 acquires feature amounts 31 will be described later.

[0021] The intensity drop portion prediction unit 22 is configured to predict the position of the intensity drop portion 53 (see FIG. 13 ) of the subject 90 based on the feature amount 31. Details of the configuration by which the intensity drop portion prediction unit 22 predicts the position of the intensity drop portion 53 of the subject 90 will be described later.

[0022] The storage unit 2c is configured to store the X-ray phase contrast image 40 generated by the image processing unit 2a, the orientation information 30 acquired by the orientation information acquisition unit 20, the feature amount 31 acquired by the feature amount acquisition unit 21, a threshold value 32 (described later), and various programs executed by the control unit 2b. The storage unit 2c includes a non-volatile storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive).

[0023] The display unit 3 is configured to display the X-ray phase contrast image 40 generated by the image processing unit 2 a. In this embodiment, the display unit 3 is also configured to display the feature amount 31 and a binarized image 43 (described later). The display unit 3 includes, for example, a liquid crystal monitor.

[0024] The input receiving unit 4 is configured to receive operation inputs from an operator and includes input devices such as a keyboard and a mouse.

[0025] As shown in FIG. 2 , the X-ray source 10, the third grating 14, the first grating 12, the second grating 13, and the X-ray detector 11 are arranged in this order along the X-ray irradiation axis 70. That is, the third grating 14, the first grating 12, and the second grating 13 are arranged between the X-ray source 10 and the X-ray detector 11. In this specification, the vertical direction is referred to as the Z direction, with the upward direction being the Z1 direction and the downward direction being the Z2 direction. The direction from the X-ray source 10 toward the X-ray detector 11 is referred to as the X direction, with one side being the X1 direction and the other side being the X2 direction. The direction perpendicular to the Z direction and the X direction is referred to as the Y direction, with one side being the Y1 direction and the other side being the Y2 direction.

[0026] The X-ray source 10 is configured to irradiate the subject 90 with X-rays. Specifically, the X-ray source 10 is configured to generate X-rays when a high voltage is applied thereto.

[0027] The X-ray detector 11 is configured to detect X-rays emitted from the X-ray source 10. The X-ray detector 11 is also configured to convert the detected X-rays into an electrical signal. The X-ray detector 11 is, for example, a flat panel detector (FPD). The X-ray detector 11 is configured with a plurality of conversion elements (not shown) and pixel electrodes (not shown) arranged on the plurality of conversion elements. The plurality of conversion elements and pixel electrodes are arranged side by side in the Y direction and the Z direction at a predetermined period (pixel pitch). A detection signal (image signal) from the X-ray detector 11 is sent to an image processing unit 2a, which will be described later.

[0028] The first grating 12 is disposed between the X-ray source 10 and the X-ray detector 11, and is irradiated with X-rays from the X-ray source 10. The first grating 12 has slits 12a and X-ray phase shifters 12b arranged at a predetermined period (grating pitch) 12c in the Z direction. Each slit 12a and X-ray phase shifter 12b is formed to extend linearly in the Y direction. The first grating 12 is a so-called phase grating. The first grating 12 is disposed between the X-ray source 10 and the second grating 13, and is provided to form a self-image (due to the Talbot effect) using X-rays irradiated from the X-ray source 10. The Talbot effect means that when coherent X-rays pass through a grating with slits formed therein, an image of the grating (self-image) is formed at a position a predetermined distance (Talbot distance) from the grating.

[0029] The second grating 13 is irradiated with X-rays from the first grating 12. The second grating 13 has a plurality of X-ray transparent portions 13a and X-ray absorbing portions 13b arranged at a predetermined period (grating pitch) 13c in the Z direction. Each of the X-ray transparent portions 13a and X-ray absorbing portions 13b is formed to extend linearly in the Y direction. The second grating 13 is a so-called absorption grating. The second grating 13 is disposed between the first grating 12 and the X-ray detector 11 and is configured to interfere with the self-image formed by the first grating 12. The second grating 13 is disposed at a position separated by a Talbot distance from the first grating 12 to cause interference between the self-image and the second grating 13.

[0030] The third grating 14 is disposed between the X-ray source 10 and the first grating 12. The third grating 14 has a plurality of slits 14a and X-ray absorbing portions 14b arranged at a predetermined period (pitch) 14c in the Z direction. Each of the slits 14a and X-ray absorbing portions 14b is formed to extend linearly in the Y direction. Furthermore, each of the slits 14a and X-ray absorbing portions 14b is formed to extend parallel to each other. The third grating 14 is disposed between the X-ray source 10 and the first grating 12, and X-rays are irradiated from the X-ray source 10. The third grating 14 is configured to convert X-rays passing through each slit 14a into a line light source corresponding to the position of each slit 14a.

[0031] In this embodiment, the first grating 12, the second grating 13, and the third grating 14 are each arranged so that the grating pattern extends in the Y direction. The grating pattern includes slits 12 a, X-ray phase shifting portions 12 b, X-ray transmitting portions 13 a, X-ray absorbing portions 13 b, slits 14 a, and X-ray absorbing portions 14 b.

[0032] The rotation mechanism 15 is configured to rotate the X-ray source 10 and the plurality of gratings relative to each other in a rotational direction about the X-ray irradiation axis 70. Specifically, the rotation mechanism 15 is provided for each of the plurality of gratings, and is configured to rotate each of the plurality of gratings in a rotational direction about the X-ray irradiation axis 70, thereby rotating the subject 90 and the plurality of gratings relative to each other in the rotational direction about the X-ray irradiation axis 70. The detailed configuration of the rotation mechanism 15 will be described later.

[0033] The grating position adjustment mechanism 16 is configured to be able to move the first grating 12 in the X direction, the Y direction, the Z direction, a rotational direction Rz around the Z-direction axis (see Figure 4), a rotational direction Rx around the X-direction axis (see Figure 4), and a rotational direction Ry around the Y-direction axis (see Figure 4).

[0034] (Rotation mechanism) Next, the configuration of the rotation mechanism 15 according to this embodiment will be described with reference to Fig. 3. Note that a rotation mechanism 15 is provided for each of the multiple gratings, but since all of the rotation mechanisms 15 have the same configuration except for the grating that they rotate, Fig. 3 will describe the rotation mechanism 15 that rotates the first grating 12 as a representative example.

[0035] The rotation mechanism 15 includes a grating holder 15a, a driver 15b that rotates the grating holder 15a in a rotational direction around an X-ray irradiation axis 70 (see FIG. 1 ), and a housing 15c that rotatably houses the grating holder 15a. The housing 15c has an opening 15d. X-rays from the X-ray source 10 (see FIG. 1 ) are irradiated onto a portion of the first grating 12 held by the grating holder 15a that faces the opening 15d (the position of the first grating 12 shown by the solid line in FIG. 3 ). The driver 15b rotates the grating holder 15a in a rotational direction around the X-ray irradiation axis 70 (see FIG. 1 ), thereby rotating the first grating 12 in the rotational direction around the X-ray irradiation axis 70. The driver 15b includes, for example, a stepping motor, a pulley, and a belt member.

[0036] (Grating position adjustment mechanism) As shown in FIG. 4, the grating position adjustment mechanism 16 includes an X-direction linear motion mechanism 16a, a Z-direction linear motion mechanism 16b, a Y-direction linear motion mechanism 16c, a linear motion mechanism connection unit 16d, a stage support unit drive unit 16e, a stage support unit 16f, a stage drive unit 16g, and a stage 16h.

[0037] The X-direction linear motion mechanism 16a, the Z-direction linear motion mechanism 16b, and the Y-direction linear motion mechanism 16c are configured to be movable in the X-direction, the Z-direction, and the Y-direction, respectively. The X-direction linear motion mechanism 16a, the Z-direction linear motion mechanism 16b, and the Y-direction linear motion mechanism 16c include, for example, stepping motors. The grating position adjustment mechanism 16 is configured to move the first grating 12 (see FIG. 1 ) in the X-direction, the Z-direction, and the Y-direction, respectively, by the operations of the X-direction linear motion mechanism 16a, the Z-direction linear motion mechanism 16b, and the Y-direction linear motion mechanism 16c.

[0038] The stage support 16f supports the stage 16h on which the first grating 12 is placed from below (Z2 direction) in FIG. 4 . The stage driver 16g is configured to reciprocate the stage 16h in the X direction. The bottom of the stage 16h is formed in a convex curved shape toward the stage support 16f. The stage 16h is configured to rotate around an axis in the Y direction (Ry direction) by reciprocating in the X direction. The stage support driver 16e is configured to reciprocate the stage support 16f in the Y direction. The bottom of the stage support 16f is formed in a convex curved shape toward the linear motion mechanism connector 16d. The stage support 16f is configured to rotate around an axis in the X direction (Rx direction) by reciprocating in the Y direction. The linear motion mechanism connector 16d is provided to the Y-direction linear motion mechanism 16c so as to be rotatable around an axis in the Z direction (Rz direction). With the above configuration, the grating position adjustment mechanism 16 can cause the first grating 12 to perform stripe scanning in the Z direction by the operation of the Z-direction linear motion mechanism 16b.

[0039] (Configuration for Generating X-ray Phase Contrast Image) Next, with reference to FIG. 5 , a configuration for generating an X-ray phase contrast image 40 (see FIG. 1 ) by the image processing unit 2a (see FIG. 1 ) will be described. The image processing unit 2a generates the X-ray phase contrast image 40 using intensity signal curves 60 and 61 acquired based on the intensity distribution of X-rays detected by the X-ray detector 11 (see FIG. 1 ). The X-ray phase contrast image 40 includes an absorption image 40a (see FIG. 6 ), a differential phase image 40b (see FIG. 6 ), and a dark-field image 40c (see FIG. 6 ). The intensity signal curve 60 is a curve that indicates the distribution of X-ray intensity obtained by imaging with the subject 90 (see FIG. 1 ) placed. The intensity signal curve 61 is a curve that indicates the distribution of X-ray intensity obtained by imaging with the subject 90 not placed.

[0040] As shown in FIG. 5 , the absorption image 40 a can be generated by the ratio of the average X-ray intensity Cs when imaging is performed with the subject 90 (see FIG. 1 ) placed to the average X-ray intensity Cr when imaging is performed without the subject 90 placed. The differential phase image 40 b can be generated by multiplying the phase difference Δφ between the intensity signal curve 60 acquired by imaging with the subject 90 placed and the intensity signal curve 61 acquired by imaging without the subject 90 placed by a predetermined calculation. The dark-field image 40 c can be generated by the ratio of the visibility (Vr) when imaging is performed without the subject 90 placed to the visibility (Vs) when imaging is performed with the subject 90 placed. Vr can be calculated by the ratio of the amplitude Ar of the intensity signal curve 60 to the average intensity Cr. Vs can be calculated by the ratio of the amplitude As of the intensity signal curve 61 to the average intensity Cs.

[0041] (Absorption Image, Differential Phase Image, and Dark-Field Image) As shown in FIG. 6, the image processing unit 2a generates an absorption image 40a, a differential phase image 40b, and a dark-field image 40c.

[0042] (Structure of Subject) Next, the structure of the subject 90 will be described with reference to FIG.

[0043] As shown in FIG. 7 , the object 90 has a plate-like shape. The object 90 is, for example, carbon fiber reinforced plastic (CFRP), which is a composite material made of carbon fiber (fibers 91 a) and a resin matrix. The object 90 can be formed, for example, by applying pressure (pressing) to a plurality of CFRP tapes 91 containing a randomly arranged plurality of resins and fibers 91 a. When the object 90 is pressed, the resin in the CFRP tapes 91 flows, filling the gaps between the CFRP tapes 91, and the object 90 is formed into a single plate-like shape. In this embodiment, the height direction of the object 90 is defined as direction A. The width direction of the object 90 is defined as direction B. The thickness direction of the object 90 is defined as direction C.

[0044] As shown in Figure 7, in a subject 90 in which randomly arranged CFRP tapes 91 are laminated, the orientation of the fibers 91a is also randomly arranged. In this case, there may be regions in which a large proportion of the fibers 91a are oriented in a specific direction. Regions in which a large proportion of the fibers 91a are oriented in a specific direction have reduced mechanical strength against a force acting in a direction intersecting the extension direction of the fibers 91a. For example, within the plane of the subject 90 (in the AB plane), regions in which a large proportion of the fibers 91a are oriented in direction A have reduced mechanical strength against a force acting in direction B.

[0045] Therefore, in this embodiment, the control unit 2b (see FIG. 1) is configured to predict the portion where the mechanical strength of the subject 90 is reduced. In this embodiment, for example, assuming that a tensile force in direction B acts on the subject 90, an example will be described in which the control unit 2b predicts the portion where the mechanical strength is reduced due to the tensile force acting in direction B.

[0046] As shown in FIG. 7 , when the subject 90 has a single plate-like shape, it may be difficult for the X-ray phase-shift imaging device 100 (see FIG. 1 ) to image the entire subject 90 at one time, depending on the size of the multiple gratings (the area of ​​the plane (YZ plane) perpendicular to the X-ray irradiation axis). Therefore, in this embodiment, an example will be described in which the subject 90 is divided into multiple regions and imaged, as shown in FIG. 8 . Specifically, an example will be described in which the subject 90 is divided into a first region 90b to a seventh region 90h at the positions indicated by dashed lines 71a to 71f in FIG. 8 , and each region is imaged.

[0047] The first region 90b is the region between the upper end of the subject 90 and the dashed line 71a. The second region 90c is the region between the dashed lines 71a and 71b. The third region 90d is the region between the dashed lines 71b and 71c. The fourth region 90e is the region between the dashed lines 71c and 71d. The fifth region 90f is the region between the dashed lines 71d and 71e. The sixth region 90g is the region between the dashed lines 71e and 71f. The seventh region 90h is the region between the dashed line 71f and the lower end of the subject 90. The example shown below is an example in which the first region 90b of the subject 90 is imaged.

[0048] 9 to 17, a configuration in which the control unit 2b (see FIG. 1) according to this embodiment acquires the feature amount 31 (see FIG. 1) will be described. In this embodiment, the control unit 2b acquires orientation information 30 (see FIG. 9) based on the dark-field image 40c (see FIG. 6) generated by the image processing unit 2a (see FIG. 1), and acquires the feature amount 31 based on the acquired orientation information 30.

[0049] (Orientation Information) First, with reference to FIGS. 9 and 10 , a configuration in which the orientation information acquisition unit 20 (see FIG. 1 ) acquires orientation information 30 (see FIG. 9 ) will be described. As shown in FIG. 9 , in this embodiment, the orientation information acquisition unit 20 acquires orientation information 30 based on a dark-field image 40c. The orientation information 30 includes an orientation angle 30a, which is the angle of the extension direction of fibers 91a (see FIG. 7 ) included in the subject 90 (see FIG. 1 ), and an orientation degree 30b, which is an index of how closely the fibers 91a are aligned in the same direction. That is, the orientation angle 30a refers to the angle of the extension direction of the fibers 91a within the plane of the subject 90 (e.g., within the AB plane) when the width direction (direction B) of the subject 90 is taken as the reference (0 degrees). The orientation degree 30b is a value indicating how closely the fibers 91a are aligned in the same direction, and takes a value between 0 and 1 depending on the degree to which the fibers 91a are aligned in the same direction.

[0050] The orientation information acquisition unit 20 acquires the orientation information 30 based on the dark-field images 40c. Specifically, the orientation information acquisition unit 20 acquires the orientation information 30 based on a plurality of dark-field images 40c captured while changing the orientation of the object 90 relative to a plurality of gratings. For example, focusing on a specific pixel 80 in the object 90, a configuration for acquiring the orientation information 30 of the pixel 80 in each dark-field image 40c will be described using a graph 33 shown in FIG. 10 .

[0051] The vertical axis of graph 33 represents pixel values ​​of dark-field image 40c (see FIG. 9), and the horizontal axis represents the angle of subject 90 relative to the multiple gratings. Graph 33 is a graph plotting pixel values ​​of corresponding pixels 80 (see FIG. 9) of multiple dark-field images 40c captured while changing the orientation of subject 90 relative to the multiple gratings.

[0052] As shown in graph 33, pixel values ​​corresponding to pixels 80 of multiple dark-field images 40c are plotted, and the angle R at which the maximum signal intensity Vmax is obtained from curve 33a fitted with a sine wave is the orientation angle 30a (see FIG. 9) of fiber 91a (see FIG. 7) at pixel 80. The value calculated from the ratio of amplitude Va to average signal intensity Vave is the degree of orientation 30b (see FIG. 9).

[0053] The orientation information acquisition unit 20 performs the same process on each pixel of the multiple dark-field images 40c to acquire orientation information 30. In this embodiment, the orientation information acquisition unit 20 acquires the orientation information 30 as tensor data indicating the orientation of the fibers 91a. The tensor data indicating the orientation is data obtained by converting the degree of orientation 30b, which is a value between 0 and 1, to a value between 0.5 and 1 and rotating the coordinate system by the orientation angle 30a. In other words, when the orientation angle 30a is set to 90 degrees and the tensor data is generated, the value of the tensor main direction (the value of the AA component) is the proportion of the fibers 91a oriented in the A direction.

[0054] (Orientation Analysis Image) The orientation analysis image 41 shown in FIG. 11 is an image generated based on the orientation information 30 (see FIG. 9). The orientation analysis image 41 is a convenient image for explaining the configuration in which the feature acquisition unit 21 acquires the feature 31. The image processing unit 2a does not need to actually generate the orientation analysis image 41. The orientation analysis image 41 is an image of the fibers 91a (see FIG. 7) included in the subject 90 (see FIG. 1) visualized using a color based on the orientation angle 30a (see FIG. 9) and a brightness based on the orientation degree 30b (see FIG. 9), as shown in legend 81. The legend 81 indicates that the color gradually changes from red, purple, blue, and light blue when the angle of the fibers 91a is in the range of 0 to 90 degrees. The legend 81 also indicates that the color gradually changes from light blue, green, yellow, and red when the angle of the fibers 91a is in the range of 90 to 180 degrees. Furthermore, in the orientation analysis image 41, the orientation angles 30a included in each pixel are displayed in a color and brightness corresponding to the orientation angle 30a with the largest orientation degree 30b value. For example, if a pixel has the largest orientation degree 30b value in the 90-degree direction, the pixel is displayed in light blue. Furthermore, for the same orientation angle 30a, the larger the orientation degree 30b value, the brighter the pixel is displayed, and the smaller the orientation degree 30b value, the darker the pixel is displayed.

[0055] Here, when the direction of the force acting on the subject 90 is direction B, by understanding the distribution of fibers 91a extending along direction A, which is a direction intersecting direction B, it is possible to understand the portions of the subject 90 where the mechanical strength is reduced in direction B. Therefore, in this embodiment, the orientation information acquisition unit 20 (see FIG. 1 ) is configured to acquire a feature quantity 31 (see FIG. 1 ) of the force acting direction based on the acting direction of the force acting on the subject 90 and orientation information 30 of the direction intersecting the acting direction of the force.

[0056] In the example shown in FIG. 11 , the fibers 91a (see FIG. 7 ) in regions 50a, 50b, and 50c are light blue and blue, respectively, and therefore have an orientation angle 30a (see FIG. 9 ) close to 90 degrees. That is, regions 50a, 50b, and 50c are specific direction fiber regions 50, which are regions of fibers 91a oriented in a direction along the specific orientation angle 30a. In the example shown in FIG. 11 , the region of fibers 91a oriented in a direction along 90 degrees is the specific direction fiber region 50. As shown in FIG. 11 , the orientation analysis image 41 shows fibers 91a with various orientation angles 30a.

[0057] (Tensor Image) Therefore, in the present embodiment, the image processing unit 2a generates a tensor image 42 shown in FIG. 12 to facilitate understanding of the specific direction fiber region 50. Specifically, as shown in FIG. 12, the image processing unit 2a (see FIG. 1) generates a tensor image 42 based on the orientation degree 30b (see FIG. 9) at a specific orientation angle 30a (see FIG. 9). The tensor image 42 shown in FIG. 12 is an image in which the pixel value is the value of the tensor principal direction obtained by converting the value of the orientation degree 30b, which is a value ranging from 0 to 1, to a value ranging from 0.5 to 1 for each pixel and rotating the coordinate system according to the orientation angle 30a. In the present embodiment, the tensor image 42 is an image in which the pixel value is the value of the tensor principal direction of the tensor data when the orientation angle 30a is 90 degrees. In the example shown in FIG. 12, the tensor image 42 is an image in which the pixel value ranges from 0 (zero) to 1, as indicated by legend 82. In regions where the proportion of fibers 91a oriented at 90 degrees (see FIG. 7 ) is high, the value of the orientation degree 30b when the orientation angle 30a is 90 degrees is large. On the other hand, in regions where the proportion of fibers 91a oriented at 0 degrees is high, the orientation degree 30b when the orientation angle 30a is 0 degrees is large, but the value of the orientation degree 30b when the orientation angle 30a is 90 degrees is small. That is, in the tensor image 42, the closer to white the color is, the higher the proportion of fibers 91a oriented in the 90-degree direction, and the closer to black the color is, the higher the proportion of fibers 91a oriented in the 0-degree direction.

[0058] In the tensor image 42, the white regions (regions 50d, 50e, and 50f) are regions where a large proportion of fibers 91a (see FIG. 7) are oriented at 90 degrees. However, in the tensor image 42, the boundary between the white regions and the black regions is unclear.

[0059] (Binarized Image) Therefore, in the present embodiment, the feature amount acquisition unit 21 (see FIG. 1) is configured to acquire feature amounts 31 (see FIG. 1) based on the tensor image 42 in order to accurately acquire the size of the specific direction fiber region 50 (see FIG. 11). Specifically, as shown in FIG. 13, the image processing unit 2a (see FIG. 1) is configured to generate a binarized image 43 by binarizing the pixel values ​​(tensor values) of the tensor image 42. In the present embodiment, the image processing unit 2a is configured to generate the binarized image 43 by binarizing the pixel values ​​of the tensor image 42 using a preset threshold value 32 (see FIG. 1).

[0060] (Feature Amount) In this embodiment, the feature amount acquisition unit 21 is configured to acquire, as the feature amount 31 (see FIG. 1), the size of a specific directional fiber region 50 (see FIG. 11), which is a region of fibers 91a oriented in a direction along a specific orientation angle 30a and shown in the tensor image 42 (see FIG. 12). In this embodiment, the feature amount acquisition unit 21 is configured to acquire, as the feature amount 31, the position of the specific directional fiber region 50, along with the size of the specific directional fiber region 50. The position of the specific directional fiber region 50 is the position coordinates of the center of the specific directional fiber region 50 in the tensor image 42.

[0061] Specifically, the feature amount acquiring unit 21 is configured to acquire the size of a binarized region 51, which is a specific direction fiber region 50 in the binarized image 43, as the feature amount 31. In this embodiment, the feature amount acquiring unit 21 is configured to acquire the feature amount 31 based on the binarized region 51, which is a region having pixel values ​​greater than a threshold value 32.

[0062] 13 shows a first binarized region 51 a, a second binarized region 51 b, and a third binarized region 51 c. The feature amount acquiring unit 21 acquires the size and position of each of the first binarized region 51 a, the second binarized region 51 b, and the third binarized region 51 c.

[0063] Here, a specific directional fiber region 50 (see FIG. 11 ), which appears as a single region in the orientation analysis image 41 (see FIG. 11 ), may become a discontinuous binarized region 51 in the binarized image 43. In this case, if the area of ​​the binarized region 51 is acquired as the feature 31, a value smaller than the actual area of ​​the specific directional fiber region 50 will be acquired as the feature 31, resulting in an inaccurate value for the feature 31. Therefore, in this embodiment, the feature acquisition unit 21 is configured to perform a smoothing process on the binarized image 43.

[0064] In this embodiment, the feature acquisition unit 21 is configured to perform, for example, morphology processing, which is a smoothing process that repeatedly performs erosion and dilation on an image. In morphology processing, discontinuous points in an image can be connected by performing erosion and dilation the same number of times. This allows binarized regions 51, which have become discontinuous regions due to binarization processing, to be connected into a single region.

[0065] In this embodiment, the feature amount acquiring unit 21 is configured to acquire, as the feature amount 31, the area of ​​the binarized region 51 after the smoothing process.

[0066] In this embodiment, feature amount 31 (see FIG. 1) includes the ratio of the area of ​​maximum binarization region 52, which is the largest binarization region 51 among binarization regions 51, to the entire area of ​​subject 90 (see FIG. 1) (the entire area of ​​first region 90b), and the position of maximum binarization region 52. In other words, feature amount acquisition unit 21 acquires the area ratio and position of first binarization region 51a, which has the largest area among first binarization region 51a, second binarization region 51b, and third binarization region 51c, as the area ratio and position of maximum binarization region 52.

[0067] (Prediction of Position of Strength Reduced Portion) In the present embodiment, the feature amount acquisition unit 21 (see FIG. 1 ) is configured to predict the position of the strength reduced portion 53, which is a portion where the mechanical strength is relatively reduced due to the orientation of the fibers 91 a (see FIG. 7 ) in the subject 90, based on the feature amount 31. Specifically, the feature amount acquisition unit 21 is configured to predict the position of the strength reduced portion 53 based on the ratio of the area of ​​the maximum binarized region 52 and the position of the maximum binarized region 52.

[0068] Table 31a shown in Fig. 14 is a table showing the area ratios of the binarized regions 51 (see Fig. 13) acquired by the feature acquisition unit 21 (see Fig. 1), the center of gravity positions of the binarized regions 51, and the fracture positions when an actual tensile test was performed. The area ratio is the ratio of the area of ​​each binarized region 51 to the area of ​​the subject 90 (see Fig. 1). Furthermore, the "region number" in Table 31a is a virtual number set according to the position of each binarized region 51. In this embodiment, the "region number" is set in ascending order of the center of gravity position value.

[0069] As shown in Table 31a, the position where the object 90 broke during the actual tensile test and the position of the maximum binarized region 52 (region No. 3) are close to each other. Therefore, similar analyses and tests were performed on various parts of the object 90 to confirm whether similar trends existed for various parts of the object 90.

[0070] Graph 34 shown in Fig. 15 is a graph showing the positions (center of gravity positions) of maximum binarized region 52 in various parts of object 90 and the fracture positions when an actual tensile test was performed. In graph 34, the horizontal axis represents the fracture positions when an actual tensile test was performed, and the vertical axis represents the center of gravity position of maximum binarized region 52. When performing the tensile test, object 90 was physically divided to create test pieces for various parts, and a tensile test was performed on each test piece.

[0071] For each part of the object 90 (see FIG. 1), the position of the maximum binarized region 52 (see FIG. 13) and point 34a, which indicates the break position during an actual tensile test, were plotted, and it was confirmed that they fell roughly between dashed lines 34b and 34c. Dashed lines 34b and 34c indicate the range in which the difference between the break position and the position of the maximum binarized region 52 is ±10 mm. In other words, it was confirmed that the predicted position of the strength reduction portion 53 (see FIG. 13) fell within a 20 mm range of the break position during an actual tensile test.

[0072] Therefore, it was confirmed that it is possible to accurately predict the breakage position when a tensile test is performed on the subject 90 based on the position (center of gravity position) of the maximum binarized region 52.

[0073] (Strength Prediction of Entire Subject) Furthermore, feature amount acquisition unit 21 (see FIG. 1) is configured to predict the mechanical strength of the entire subject 90 (see FIG. 1) based on feature amounts 31 (see FIG. 1) of strength-reduced portions 53 (see FIG. 13) included in the entire subject 90. Specifically, feature amount acquisition unit 21 is configured to acquire an index value of the mechanical strength of the entire subject 90 based on the ratio of the area of ​​all binarized regions 51 (see FIG. 13) to the area of ​​the entire subject 90.

[0074] In the graph 35 shown in FIG. 16 , the horizontal axis represents the test piece number, the left vertical axis represents the maximum stress (MPa: megapascals), and the right vertical axis represents the total area ratio (%) of the binarized region 51 (see FIG. 13 ). As shown in legend 35 a, the broken line 35 b with circles indicates the total area ratio, and the solid line 35 c with squares indicates the maximum stress. The total area ratio is the sum of the ratios of the areas of the binarized regions 51 to the entire area of ​​the subject 90 appearing in the binarized image 43 (see FIG. 13 ). In other words, the total area ratio is the ratio of the area of ​​all the binarized regions 51 to the entire area of ​​the subject 90 appearing in the binarized image 43.

[0075] As shown in graph 35, it was confirmed that the maximum stress tends to decrease when the total area ratio is large, and the maximum stress tends to increase when the total area ratio is small. In other words, it was confirmed that there is a high correlation between the total area ratio and the maximum stress for each test piece. Therefore, the sum of the area ratios of all binarized regions 51 can be used as an index value for the mechanical strength of the entire object 90 (see FIG. 1).

[0076] (Fiber Orientation Bias Tendency) The example shown in Fig. 17(A) is a binarized image 43a in the case where the orientation of fibers 91a (see Fig. 7) in the subject 90 (see Fig. 1) is strongly biased. The example shown in Fig. 17(B) is a binarized image 43b in the case where the orientation of fibers 91a in the subject 90 is weakly biased.

[0077] 17A, when the orientation of the fibers 91a is strongly biased, the size (area) of the binarized regions 51 tends to be larger and the number of binarized regions 51 tends to be smaller than when the orientation of the fibers 91a is weakly biased. In other words, when the orientation of the fibers 91a is strongly biased, the size (area) of the specific direction fiber regions 50 (see FIG. 11) tends to be larger and the number of them tends to be smaller.

[0078] 17(B), when the orientation of the fibers 91a is weakly biased, the size (area) of the binarized regions 51 tends to be smaller and the number of binarized regions 51 tends to be larger compared to when the orientation of the fibers 91a is strongly biased. In other words, when the orientation of the fibers 91a is weakly biased, the size (area) of the specific direction fiber regions 50 tends to be smaller and the number of them tends to be larger.

[0079] If the orientation of the fibers 91 a in the subject 90 is highly biased, there may be portions where the mechanical strength is reduced due to the orientation of the fibers 91 a. On the other hand, if the orientation of the fibers 91 a in the subject 90 is weakly biased, the fibers 91 a are arranged in random directions, which reduces the possibility of there being portions where the mechanical strength is reduced due to the orientation of the fibers 91 a.

[0080] Therefore, in this embodiment, the feature amount acquiring unit 21 (see FIG. 1 ) is configured to acquire the tendency of bias in the orientation of the fibers 91 a within the subject 90 based on the size and number of the binarized regions 51 in the binarized image 43. In this embodiment, the feature amount acquiring unit 21 is configured to acquire the tendency of bias in the orientation of the fibers 91 a within the subject 90 based on the area and number of the binarized regions 51.

[0081] (Display of dark-field image, binary image, and feature values) Next, referring to Figure 18, we will explain the configuration in which the control unit 2b (see Figure 1) displays the dark-field image 40c, binary image 43, feature value 31, predicted fracture position 36, and total area ratio 31b on the display unit 3.

[0082] The control unit 2b is configured to display the dark field image 40c, the binarized image 43, the table 31a of the features 31, the predicted fracture location 36, and the total area ratio 31b side by side on the display unit 3.

[0083] Furthermore, although not shown, when the orientation bias of the fibers 91a is weak, the control unit 2b does not display the table 31a of the feature values ​​31, the predicted breakage position 36, and the total area ratio 31b, but displays on the display unit 3 that the subject 90 is not suitable for analysis according to this embodiment.

[0084] Next, with reference to FIG. 19, a process in which the control unit 2b (see FIG. 1) according to this embodiment displays the feature amount 31 (see FIG. 1) on the display unit 3 (see FIG. 1) will be described.

[0085] In step 101, the control unit 2b controls the X-ray source 10 (see FIG. 1) and the rotation mechanism 15 (see FIG. 1) to image the subject 90 (see FIG. 1) and a plurality of gratings arranged between the X-ray source 10 and the X-ray detector 11 (see FIG. 1) at a plurality of imaging angles while rotating them relative to each other in a rotational direction around the X-ray irradiation axis 70 (see FIG. 1).

[0086] In step 102, the image processing unit 2a (see FIG. 1) generates a plurality of X-ray phase contrast images 40 (see FIG. 1) for each orientation of the subject 90 with respect to the plurality of gratings, based on the intensity distribution of X-rays detected by the X-ray detector 11. In this embodiment, the image processing unit 2a generates at least a plurality of dark-field images 40c (see FIG. 6) as the plurality of phase contrast images.

[0087] In step 103, the feature acquisition unit 21 (see FIG. 1 ) acquires orientation information 30 (see FIG. 9 ) regarding the orientation of fibers 91 a included in the subject 90, based on the multiple X-ray phase contrast images 40. In this embodiment, the control unit 2 b acquires the orientation information 30 based on the multiple dark-field images 40 c.

[0088] In step 104, feature amount acquiring unit 21 (see FIG. 1) acquires feature amounts 31 related to the mechanical strength of object 90 based on orientation information 30 acquired in step 103. In this embodiment, feature amount acquiring unit 21 acquires, in step 104, as feature amounts 31, the area ratio of maximum binarized region 52 (see FIG. 13 ), the position of maximum binarized region 52, and the area ratio of all binarized regions 51 (see FIG. 13 ).

[0089] In step 105, the control unit 2b determines whether the size (area) and number of binarized regions 51 having pixel values ​​equal to or greater than the threshold value 32 (see FIG. 1) are equal to or greater than a predetermined size (area) and number. If the size (area) and number of binarized regions 51 having pixel values ​​equal to or greater than the threshold value 32 are equal to or greater than the predetermined size (area) and number, the process proceeds to step 106. If the size (area) and number of binarized regions 51 having pixel values ​​equal to or greater than the threshold value 32 are not equal to or greater than the predetermined size (area) and number, the process proceeds to step 107.

[0090] In step 106, the control unit 2b displays the feature amount 31 on the display unit 3. In this embodiment, the control unit 2b displays, as the feature amount 31, the area ratio of the largest binarized region 52, the position of the largest binarized region 52, and the area ratio of all binarized regions 51. The control unit 2b also displays the dark-field image 40c and the binarized image 43 (see FIG. 13 ) along with the feature amount 31 on the display unit 3. Then, the processing ends.

[0091] When the process proceeds from step 105 to step 107, in step 107 the control unit 2b notifies the user that the subject 90 is not suitable for analysis by the X-ray phase imaging device 100. Specifically, the control unit 2b displays a message on the display unit 3 indicating that the subject 90 is not suitable for analysis by the X-ray phase imaging device 100. Then, the process ends.

[0092] (Effects of this embodiment) In this embodiment, the following effects can be obtained.

[0093] In this embodiment, as described above, the X-ray phase imaging device 100 is an X-ray phase imaging device for predicting positions where the mechanical strength of the object 90 including fibers 91 a is reduced, and includes an X-ray source 10 for irradiating X-rays, an X-ray detector 11 for detecting the X-rays irradiated from the X-ray source 10, a plurality of gratings arranged between the X-ray source 10 and the X-ray detector 11, a rotation mechanism 15 for relatively rotating the object 90 and the plurality of gratings in a rotation direction around the X-ray irradiation axis 70, and a rotation mechanism 15 for relatively rotating the object 90 and the plurality of gratings by the rotation mechanism 15, thereby detecting the positions where the mechanical strength of the object 90 is reduced. The apparatus is equipped with an image processing unit 2a that generates multiple X-ray phase contrast images 40 for each orientation of the subject 90 relative to the multiple gratings based on the X-ray intensity distribution detected by the X-ray detector 11 by changing the orientation of the subject 90 and capturing an image, and a control unit 2b (orientation information acquisition unit 20 and feature acquisition unit 21) that acquires orientation information 30 regarding the orientation of fibers 91a contained in the subject 90 based on the multiple X-ray phase contrast images 40, and acquires feature values ​​31 regarding the mechanical strength of the subject 90 based on the acquired orientation information 30.

[0094] This allows the user to check the feature quantity 31 related to the mechanical strength of the subject 90 acquired based on the orientation information 30. As a result, it is possible to easily grasp the part of the subject 90 where the mechanical strength is reduced due to the orientation of the fibers 91 a.

[0095] Furthermore, in this embodiment, as described above, the X-ray phase imaging image analysis method is an X-ray phase imaging image analysis method for predicting locations where the mechanical strength of a subject 90 containing fibers 91a is reduced, and includes the steps of: imaging the subject 90 and a plurality of gratings arranged between the X-ray source 10 and the X-ray detector 11 at a plurality of imaging angles while rotating them relatively in a rotational direction around the X-ray irradiation axis 70; generating a plurality of X-ray phase contrast images 40 for each orientation of the subject 90 relative to the plurality of gratings based on the X-ray intensity distribution detected by the X-ray detector 11; acquiring orientation information 30 regarding the orientation of fibers 91a included in the subject 90 based on the plurality of X-ray phase contrast images 40; and acquiring feature quantities 31 regarding the mechanical strength of the subject 90 based on the acquired orientation information 30.

[0096] This makes it possible to provide an X-ray phase imaging method that, similar to the above-mentioned X-ray phase imaging device 100, can easily identify areas in the subject 90 where mechanical strength is reduced due to the orientation of the fibers 91a.

[0097] Furthermore, in the above embodiment, the following additional effects can be obtained by configuring as follows.

[0098] That is, in this embodiment, as described above, the control unit 2b (feature amount acquisition unit 21) is configured to acquire the feature amount 31 of the force acting direction based on the acting direction of the force acting on the subject 90 and the orientation information 30 of the direction intersecting the force acting direction. This allows the user to easily grasp the mechanical strength of the subject 90 in the direction of the force acting by checking the feature amount 31.

[0099] Furthermore, in this embodiment, as described above, the control unit 2b (the strength-reduced portion prediction unit 22) is configured to predict the position of the strength-reduced portion 53, which is a portion in the object 90 where the mechanical strength is relatively reduced due to the orientation of the fibers 91a, based on the feature quantity 31. This allows the position of the strength-reduced portion 53 to be predicted. For example, by discarding the strength-reduced portion 53 and using the remaining portion in the product, it is possible to prevent a decrease in product yield. Furthermore, based on the predicted position of the strength-reduced portion 53, it is possible to identify a region in the object 90 where fibers 91a oriented in a specific direction are concentrated (specific-direction fiber region 50). As a result, for example, in the object 90 manufactured by arranging the fibers 91a in random directions, this can be utilized to improve the product manufacturing process, such as by modifying the manufacturing process to prevent the fibers 91a oriented in a specific direction from concentrating in a specific region.

[0100] Furthermore, in this embodiment, as described above, the control unit 2b (strength reduced portion prediction unit 22) is configured to predict the mechanical strength of the entire subject 90 based on the feature amounts 31 of the strength reduced portions 53 included in the entire subject 90. Thus, by predicting the mechanical strength of the entire subject 90 based on the feature amounts 31, it is possible to easily grasp the quality of the mechanical strength of the subject 90. As a result, quality control of the mechanical strength of the subject 90 can be easily performed.

[0101] Furthermore, in this embodiment, as described above, the orientation information 30 includes an orientation angle 30a, which is the angle of the direction in which the fibers 91a contained in the subject 90 extend, and an orientation degree 30b, which is an index showing how closely the fibers 91a are aligned in the same direction. The image processing unit 2a is configured to generate a tensor image 42, which is an image based on the orientation degree 30b at a specific orientation angle 30a. The control unit 2b (feature acquisition unit 21) is configured to acquire a feature 31 based on the tensor image 42. Thus, by generating the tensor image 42 at the orientation angle 30a desired by the user, the feature 31 related to the mechanical strength of the subject 90 in the direction desired by the user can be acquired. As a result, the user can easily grasp the mechanical strength of the subject 90 in the direction desired by the user by checking the feature 31.

[0102] Furthermore, in this embodiment, as described above, the control unit 2b (feature acquisition unit 21) is configured to acquire, as the feature 31, the size of the specific directional fiber region 50, which is a region of fibers 91a oriented in a direction along the specific orientation angle 30a shown in the tensor image 42. Here, the greater the proportion of fibers 91a oriented in a direction intersecting the direction of the force acting on the subject 90, the lower the mechanical strength of the subject 90. That is, the larger the size of the specific directional fiber region 50, the lower the mechanical strength of the subject 90. Therefore, by acquiring the size of the specific directional fiber region 50 as the feature 31, the size of the specific directional fiber region 50 can be presented to the user as the feature 31. As a result, the user can easily grasp the degree to which the mechanical strength of the subject 90 has decreased by checking the size of the specific directional fiber region 50. Furthermore, the size of the specific directional fiber region 50 can be used to quantitatively grasp the mechanical strength of the subject 90.

[0103] In this embodiment, as described above, the control unit 2b (feature amount acquisition unit 21) is configured to acquire the size of the specific directional fiber region 50 as well as the position of the specific directional fiber region 50 as feature amounts 31. This allows the user to grasp the degree of reduction in the mechanical strength of the subject 90 and the location where the mechanical strength is reduced. As a result, the user can easily grasp the location of the strength-reduced portion 53, which is a location where damage may occur in the subject 90.

[0104] Furthermore, in this embodiment, as described above, the image processing unit 2a is configured to generate a binarized image 43 by binarizing the pixel values ​​of the tensor image 42, and the control unit 2b (feature acquisition unit 21) is configured to acquire the size of a binarized region 51, which is a specific directional fiber region 50, in the binarized image 43 as the feature 31. Here, in an image (tensor image 42) in which pixel values ​​are based on the orientation degree 30b of a specific orientation angle 30a, the boundary of the specific directional fiber region 50 becomes unclear in regions where the orientation degree 30b gradually changes. If the boundary of the specific directional fiber region 50 becomes unclear, the size of the specific directional fiber region 50 may not be accurately acquired. Therefore, as described above, by acquiring the size of the binarized region 51, which is the specific directional fiber region 50 in the binarized image 43, as the feature 31, the size of the specific directional fiber region 50 can be acquired with greater accuracy than in a configuration in which the size of the specific directional fiber region 50 in an image of pixel values ​​based on the orientation degree 30b of the specific orientation angle 30a (tensor image 42) is acquired as the feature 31. As a result, the feature 31 can be acquired with greater accuracy.

[0105] In this embodiment, as described above, the control unit 2b (feature acquisition unit 21) is configured to perform a smoothing process on the binarized image 43 and acquire the area of ​​the binarized region 51 after the smoothing process as the feature 31. Here, the specific directional fiber region 50, which is a single region in the orientation analysis image 41, may become a discontinuous binarized region 51 in the binarized image 43. In this case, if the area of ​​the binarized region 51 is acquired as the feature 31, a value smaller than the actual area of ​​the specific directional fiber region 50 is acquired, resulting in a decrease in the accuracy of the feature 31. Therefore, by acquiring the area of ​​the binarized region 51 after the smoothing process as the feature 31, the binarized region 51, which has become a discontinuous region due to the binarization process, can be treated as a single region. As a result, a decrease in the accuracy of the feature 31 can be suppressed.

[0106] Furthermore, in this embodiment, as described above, the feature amount 31 includes the ratio of the area of ​​the largest binarized region 52, which is the largest binarized region 51 among the binarized regions 51, to the area of ​​the entire subject 90, and the position of the largest binarized region 52. The control unit 2b (feature amount acquisition unit 21) is configured to predict the position of the strength reduction portion 53 based on the ratio of the area of ​​the largest binarized region 52 and the position of the largest binarized region 52. Here, a region with a large area ratio of the binarized region 51 is a region with a high proportion of fibers 91a with a specific orientation angle 30a, and therefore is a region with reduced mechanical strength. Therefore, by configuring as described above, it is possible to easily predict the position of the subject 90 where the mechanical strength is lowest.

[0107] Furthermore, in this embodiment, as described above, the feature amount 31 includes the ratio of the area of ​​all the binarized regions 51 to the area of ​​the entire subject 90, and the control unit 2b (feature amount acquisition unit 21) is configured to acquire an index value of the mechanical strength of the entire subject 90 based on the ratio of the area of ​​all the binarized regions 51 to the area of ​​the entire subject 90. This allows the user to easily grasp the mechanical strength of the entire subject 90 by checking the index value of the mechanical strength of the entire subject 90 acquired based on the ratio of the area of ​​all the binarized regions 51 to the area of ​​the entire subject 90.

[0108] Furthermore, in this embodiment, as described above, the control unit 2b (feature acquisition unit 21) is configured to acquire the feature 31 based on the binarized region 51, which is a region having a value greater than the preset threshold 32. Here, regions with small pixel values ​​in the tensor image 42 have a higher proportion of fibers 91a oriented in directions other than the specific orientation angle 30a than regions with large pixel values. That is, regions with small pixel values ​​in the tensor image 42 have a smaller degree of reduction in mechanical strength in the direction intersecting the specific orientation angle 30a than regions with large pixel values. Therefore, by acquiring regions with values ​​greater than the threshold 32 as the binarized region 51 as described above, the accuracy of predicting portions of the subject 90 with reduced mechanical strength can be improved.

[0109] Furthermore, in this embodiment, as described above, the control unit 2b is configured to acquire the bias tendency of the fibers 91a in the subject 90 based on the size and number of the binarized regions 51 in the binarized image 43. Here, if the bias in the orientation of the fibers 91a is weak, the size of the specific direction fiber region 50 will be small. In this case, even if binarization processing is performed using the threshold value 32, the binarized region 51 may not be obtained. Therefore, by acquiring the bias tendency of the fibers 91a in the subject 90 as described above, the threshold value 32 can be set according to the bias in the orientation of the fibers 91a. As a result, the binarized region 51 can be reliably acquired. Furthermore, if the bias in the orientation of the fibers 91a is weak, a decrease in mechanical strength due to the orientation of the fibers 91a may not occur. Therefore, by acquiring the bias tendency of the fibers 91a in the subject 90, the user can determine whether the subject is suitable for analysis performed by the X-ray phase imaging apparatus 100 according to this embodiment. As a result, user convenience (usability) can be improved.

[0110] [Modifications] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is defined by the claims, not by the description of the above-mentioned embodiments, and further includes all modifications (modifications) within the meaning and scope of the claims.

[0111] For example, in the above embodiment, the X-ray phase imaging device 100 is configured to include only the rotation mechanism 15 that rotates the object 90 and the plurality of gratings relative to each other, but the present invention is not limited to this. As in a modified X-ray phase imaging device 200 shown in Fig. 20, the device may further include a second rotation mechanism 17 that rotates the object 90 relative to an imaging system including the X-ray source 10, the plurality of gratings, and the X-ray detector 11.

[0112] The modified X-ray phase imaging device 200 shown in Figure 20 differs from the X-ray phase imaging device 100 of the above embodiment in that it has an X-ray imaging unit 201 instead of the X-ray imaging unit 1, and a computer 202 instead of the computer 2.

[0113] The X-ray imaging unit 201 according to the modified example differs from the X-ray imaging unit 1 according to the above embodiment in that it further includes a second rotation mechanism 17 .

[0114] The second rotation mechanism 17 is configured to relatively rotate the subject 90 and an imaging system including the X-ray source 10, the plurality of gratings, and the X-ray detector 11. Details of the configuration of the second rotation mechanism 17 to relatively rotate the subject 90 and the imaging system including the X-ray source 10, the plurality of gratings, and the X-ray detector 11 will be described later.

[0115] The computer 202 according to the modified example also differs from the computer 2 according to the above embodiment in that it includes an image processing unit 202a and a control unit 202b instead of the image processing unit 2a and the control unit 2b.

[0116] The image processing unit 202a is configured to generate a three-dimensional phase contrast image by taking images while changing the angle between the subject 90 and the imaging system using the second rotation mechanism 17 and changing the orientation of the subject 90 and the multiple gratings using the rotation mechanism 15.

[0117] 21 , the second rotation mechanism 17 is configured to rotate the subject 90 and the imaging system relatively in a rotational direction about an axis 72 perpendicular to the X-ray irradiation axis 70. Specifically, the second rotation mechanism 17 is configured to rotate the subject 90 and the imaging system relatively by rotating the subject 90 in a rotational direction about the axis 72 perpendicular to the X-ray irradiation axis 70. The second rotation mechanism 17 includes a mounting portion (not shown) on which the subject 90 is mounted, and a driving portion (not shown) that generates a driving force to rotate the mounting portion.

[0118] Therefore, the image processing unit 202a can generate binary images 43 (first binary image 43c to fifth binary image 43g) of each cross section in the thickness direction (X direction) of the subject 90 (see Figure 20), as shown in Figure 22.

[0119] 22 illustrates the first to fifth binarized images 43c to 43g arranged along the thickness direction (X direction) of the subject 90. As illustrated in FIG. 22 , the binarized region 51 of the first binarized image 43c and the binarized region 51 of the second binarized image 43d overlap in the thickness direction of the subject 90. Furthermore, the binarized region 51 of the second binarized image 43d and the binarized region 51 of the third binarized image 43e overlap in the thickness direction of the subject 90. Furthermore, the binarized region 51 of the third binarized image 43e and the binarized region 51 of the fourth binarized image 43f overlap in the thickness direction of the subject 90. Furthermore, the binarized region 51 of the fourth binarized image 43f and the binarized region 51 of the fifth binarized image 43g overlap in the thickness direction of the subject 90. 22, the specific direction fiber region 50 (see FIG. 11) is continuous along the thickness direction of the object 90. Therefore, when a force acts on the object 90 in the direction B, the object 90 is likely to break.

[0120] The X-ray phase imaging device 200 according to the modified example can obtain a tomographic image to grasp in detail the distribution in the thickness direction (X direction) of the specific direction fiber region 50. As a result, it is possible to grasp in more detail the portion where the mechanical strength is reduced.

[0121] In the above embodiment, the control unit 2b predicts the location of the portion where the tensile strength is reduced, but the present invention is not limited to this. For example, the control unit 2b may be configured to predict the fracture location in a three-point bending test.

[0122] Furthermore, in the above embodiment, an example of a configuration has been shown in which the control unit 2b predicts both the position of the strength reduced portion 53, which is a portion of the subject 90 where the mechanical strength is reduced, and the mechanical strength of the entire subject 90, but the present invention is not limited to this. As long as the position of at least the strength reduced portion 53, which is a portion of the subject 90 where the mechanical strength is reduced, is predicted, it is not necessary to predict the mechanical strength of the entire subject 90.

[0123] In the above embodiment, the feature amount acquiring unit 21 acquires the size and position of the specific directional fiber region 50, but the present invention is not limited to this. For example, if the feature amount acquiring unit 21 is configured to acquire the size of the specific directional fiber region 50 for each region obtained by dividing the dark-field image 40c by a predetermined size (width), it is not necessary to acquire the position of the specific directional fiber region 50.

[0124] In the above embodiment, the feature amount acquiring unit 21 acquires the area ratio of the binarized region 51 as the feature amount 31. However, the present invention is not limited to this. For example, the feature amount acquiring unit 21 may be configured to acquire the area value of the binarized region 51 as the feature amount 31. The feature amount acquiring unit 21 may be configured to acquire the perimeter length of the binarized region 51 as the feature amount 31. The feature amount acquiring unit 21 may be configured to acquire a circumscribing rectangle of the binarized region 51 and acquire the length of the longest side of the circumscribing rectangle as the feature amount 31. The feature amount acquiring unit 21 may be configured to fit the binarized region 51 to an ellipse and acquire a value based on the ratio between the long side and the short side of the fitted ellipse as the feature amount 31. The feature amount acquiring unit 21 may be configured to acquire the size of the binarized region 51 by any method.

[0125] Furthermore, in the above embodiment, an example of a configuration in which the feature acquisition unit 21 performs morphology processing as the smoothing processing on the binarized image 43 has been described, but the present invention is not limited to this. The feature acquisition unit 21 may perform any processing as long as it is possible to connect discontinuous binarized regions 51. For example, the feature acquisition unit 21 may be configured to perform processing using a Gaussian filter as the smoothing processing on the binarized image 43. However, smoothing processing using a Gaussian filter may result in a decrease in accuracy when connecting the binarized regions 51. Therefore, it is preferable that the feature acquisition unit 21 be configured to perform morphology processing as the smoothing processing.

[0126] In the above embodiment, the control unit 2b displays the feature quantities 31 (table 31a), the dark-field image 40c, the binarized image 43, the predicted fracture position 36, and the total area ratio 31b on the display unit 3, but the present invention is not limited to this. The control unit 2b does not need to display the dark-field image 40c, the binarized image 43, the predicted fracture position 36, or the total area ratio 31b as long as it displays at least the feature quantities 31. In addition, the control unit 2b displays the table 31a of the feature quantities 31, but may be configured to display only the numerical data of the area ratio of the maximum binarized region 52 and the position of the maximum binarized region 52.

[0127] In the above embodiment, the feature amount acquiring unit 21 binarizes the pixel values ​​of the tensor image 42 using a preset threshold value 32. However, the present invention is not limited to this. For example, the feature amount acquiring unit 21 may be configured to binarize the pixel values ​​of the tensor image 42 using a threshold value input by a user.

[0128] In the above embodiment, the feature amount acquiring unit 21 acquires the tendency of the bias in the orientation of the fibers 91 a, but the present invention is not limited to this. For example, the feature amount acquiring unit 21 does not have to acquire the tendency of the bias in the orientation of the fibers 91 a.

[0129] 3, the rotation mechanism 15 includes the grating holder 15a, the drive unit 15b, and the storage unit 15c. However, the present invention is not limited to this. The rotation mechanism 15 may have any configuration as long as it can rotate the gratings in a rotational direction around the X-ray irradiation axis 70.

[0130] In the above embodiment, the rotation mechanism 15 rotates the plurality of gratings to rotate the object 90 relative to the plurality of gratings, but the present invention is not limited to this. For example, the rotation mechanism 15 may be configured to rotate the object 90 relative to the plurality of gratings.

[0131] In the above embodiment, the X-ray phase imaging device 100 is configured to image CFRP as the object 90, but the present invention is not limited to this. For example, the X-ray phase imaging device 100 may be configured to image GFRP (glass fiber reinforced plastic) as the object. Any object may be imaged as long as it is a fiber composite material.

[0132] In the above embodiment, the subject 90 is divided into the first area 90b to the seventh area 90h, and an image is captured for each area. However, the present invention is not limited to this. If it is possible to capture an image of the entire subject 90, it is not necessary to capture the subject 90 by dividing it into multiple areas.

[0133] Furthermore, in the above embodiment, an example was shown in which the grating position adjustment mechanism 16 was configured to be able to move the first grating 12 in the X direction, Y direction, Z direction, rotational direction Rz, rotational direction Rx, and rotational direction Ry, but the present invention is not limited to this. In the present invention, the grating position adjustment mechanism 16 may be configured to be able to move only one or more of the X direction, Y direction, Z direction, rotational direction Rz, rotational direction Rx, and rotational direction Ry. Furthermore, the grating position adjustment mechanism 16 may be configured to be able to move the second grating 13 or the third grating 14. Note that, when fringe scanning is performed, the grating position adjustment mechanism 16 needs to be configured to be able to move the grating in the direction in which fringe scanning is performed.

[0134] In the above embodiment, the plurality of gratings includes the third grating 14 for increasing the coherence of the X-rays emitted from the X-ray source 10, but the present invention is not limited to this. If the coherence of the X-rays emitted from the X-ray source 10 is high, the configuration may not include the third grating 14.

[0135] In the above embodiment, the first grating 12 is a phase grating to form a self-image due to the Talbot effect, but the present invention is not limited to this. In the present invention, the self-image only needs to be a striped pattern, so an absorption grating may be used instead of a phase grating. When an absorption grating is used, a region where a striped pattern simply occurs (non-interferometer) and a region where a self-image due to the Talbot effect occurs (interferometer) are generated depending on optical conditions such as distance.

[0136] Aspects It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0137] an X-ray phase contrast image processing unit that generates a plurality of X-ray phase contrast images for each orientation of the subject relative to the plurality of gratings based on the X-ray intensity distribution detected by the X-ray detector by rotating the subject relative to the plurality of gratings using the rotation mechanism and changing the orientation of the subject relative to the plurality of gratings while capturing images; and a control unit that acquires orientation information regarding the orientation of the fibers included in the subject based on the plurality of X-ray phase contrast images, and acquires feature quantities regarding the mechanical strength of the subject based on the acquired orientation information.

[0138] (Item 2) The X-ray phase imaging apparatus according to Item 1, wherein the control unit is configured to acquire the feature amount of the force acting direction based on the force acting direction acting on the subject and the orientation information of a direction intersecting the force acting direction.

[0139] (Item 3) The X-ray phase imaging apparatus according to item 1 or 2, wherein the control unit is configured to predict, based on the feature amount, a position of a strength reduction portion, which is a portion where mechanical strength is relatively reduced due to the orientation of the fibers in the subject.

[0140] (Item 4) The X-ray phase imaging apparatus according to Item 3, wherein the control unit is configured to predict the mechanical strength of the entire subject based on the feature amount of the intensity reduction portion included in the entire subject.

[0141] (Item 5) The X-ray phase imaging device described in Item 3 or 4, wherein the orientation information includes an orientation angle, which is the angle of the direction in which the fibers contained in the subject extend, and an orientation degree, which is an index of how aligned the fibers are in the same direction; the image processing unit is configured to generate an orientation information image, which is an image based on the orientation degree at a specific orientation angle; and the control unit is configured to acquire the feature amount based on the orientation information image.

[0142] (Item 6) The X-ray phase imaging device according to Item 5, wherein the control unit is configured to acquire, as the feature amount, a size of a specific direction fiber region, which is a region of the fibers that are oriented in a direction along the specific orientation angle that appears in the orientation information image.

[0143] (Item 7) The X-ray phase imaging apparatus according to Item 6, wherein the control unit is configured to acquire, as the feature amount, the position of the specific directional fiber region as well as the size of the specific directional fiber region.

[0144] (Item 8) The X-ray phase imaging device described in Item 6 or 7, wherein the image processing unit is configured to generate a binary image by binarizing pixel values ​​of the orientation information image, and the control unit is configured to acquire the size of the binary region that is the specific direction fiber region in the binary image as the feature amount.

[0145] (Item 9) The X-ray phase imaging apparatus according to Item 8, wherein the control unit is configured to perform a smoothing process on the binarized image and to acquire an area of ​​the binarized region after the smoothing process as the feature amount.

[0146] (Item 10) The X-ray phase imaging device described in Item 8 or 9, wherein the feature amount includes a ratio of an area of ​​a maximum binarized region, which is the largest of the binarized regions, to an area of ​​the entire subject, and a position of the maximum binarized region, and the control unit is configured to predict the position of the intensity reduction portion based on the ratio of the area of ​​the maximum binarized region and the position of the maximum binarized region.

[0147] (Item 11) The X-ray phase imaging device according to Item 8 or 9, wherein the feature amount includes a ratio of the area of ​​all the binarized regions to the area of ​​the entire subject, and the control unit is configured to acquire an index value of the mechanical strength of the entire subject based on the ratio of the area of ​​all the binarized regions to the area of ​​the entire subject.

[0148] (Item 12) The X-ray phase imaging apparatus according to any one of Items 8 to 11, wherein the control unit is configured to acquire the feature amount based on the binarized region, which is a region having a value greater than a preset threshold value.

[0149] (Item 13) The X-ray phase imaging device according to any one of Items 8 to 12, wherein the control unit is configured to acquire a tendency of bias in the orientation of the fibers within the subject based on the size and number of the binarized regions in the binarized image.

[0150] (Item 14) An X-ray phase imaging image analysis method for predicting locations where the mechanical strength of a subject containing fibers is reduced, comprising: a step of imaging the subject and a plurality of gratings arranged between an X-ray source and an X-ray detector at a plurality of imaging angles while rotating them relatively in a rotational direction around the X-ray irradiation axis direction; a step of generating a plurality of X-ray phase contrast images for each orientation of the subject relative to the plurality of gratings based on the X-ray intensity distribution detected by the X-ray detector; a step of acquiring orientation information regarding the orientation of the fibers contained in the subject based on the plurality of X-ray phase contrast images; and a step of acquiring feature quantities regarding the mechanical strength of the subject based on the acquired orientation information.

[0151] 2a, 202a Image processing unit 2b, 202b Control unit 10 X-ray source 11 X-ray detector 15 Rotation mechanism 30 Orientation information 30a Orientation angle 30b Orientation degree 31 Feature amount (feature amount related to the mechanical strength of the object) 32 Threshold 40 X-ray phase contrast image 42 Tensor image (orientation information image) 43 Binarized image 50 Specific direction fiber region 51 Binarized region 52 Maximum binarized region 53 Strength reduction region 70 X-ray irradiation axis 90 Object 91a Fiber 100, 200 X-ray imaging device

Claims

1. An X-ray phase imaging apparatus for predicting a position where mechanical strength of a subject including fibers is reduced, comprising: An X-ray source that emits X-rays; an X-ray detector for detecting X-rays irradiated from the X-ray source; a plurality of gratings disposed between the X-ray source and the X-ray detector; a rotation mechanism that rotates the subject and the plurality of gratings relatively in a rotation direction around an irradiation axis of X-rays; an image processing unit that generates a plurality of X-ray phase contrast images for each orientation of the subject with respect to the plurality of gratings based on the intensity distribution of X-rays detected by the X-ray detector by rotating the subject and the plurality of gratings relatively by the rotation mechanism and capturing images while changing the orientation of the subject with respect to the plurality of gratings; and a control unit that acquires orientation information regarding the orientation of the fibers contained in the subject based on the multiple X-ray phase contrast images, and acquires features regarding the mechanical strength of the subject based on the acquired orientation information.

2. The X-ray phase imaging apparatus of claim 1 , wherein the control unit is configured to acquire the characteristic amount of the direction of action of a force acting on a subject based on the direction of action of the force and the orientation information of a direction intersecting the direction of action of the force.

3. The X-ray phase imaging apparatus according to claim 2 , wherein the control unit is configured to predict a position of a strength reduction portion, which is a portion where mechanical strength is relatively reduced due to the orientation of the fibers within the subject, based on the feature amount.

4. The X-ray phase-shift imaging apparatus according to claim 3 , wherein the control unit is configured to predict a mechanical strength of the entire object based on the feature amount of the strength reduction portion included in the entire object.

5. The orientation information includes an orientation angle, which is an angle of a direction in which the fibers included in the subject extend, and an orientation degree, which is an index of how much the fibers are aligned in the same direction; The image processing unit is configured to generate an orientation information image that is an image based on the orientation degree at the specific orientation angle, The X-ray phase-shift imaging apparatus according to claim 3 , wherein the control unit is configured to acquire the feature amount based on the orientation information image.

6. The X-ray phase imaging device according to claim 5, wherein the control unit is configured to acquire, as the feature amount, a size of a specific directional fiber region, which is a region of the fibers oriented in a direction along the specific orientation angle shown in the orientation information image.

7. The X-ray phase-shift imaging apparatus according to claim 6 , wherein the control unit is configured to acquire a position of the specific directional fiber region as well as a size of the specific directional fiber region as the feature amount.

8. the image processing unit is configured to generate a binary image by performing a binarization process on pixel values ​​of the orientation information image, The X-ray phase-shift imaging apparatus according to claim 7 , wherein the control unit is configured to acquire, as the feature amount, a size of a binarized region that is the specific directional fiber region in the binarized image.

9. 9. The X-ray phase imaging apparatus according to claim 8, wherein the control unit is configured to perform a smoothing process on the binarized image and to acquire an area of ​​the binarized region after the smoothing process as the feature amount.

10. the feature amount includes a ratio of an area of ​​a maximum binarized region, which is the largest of the binarized regions, to an area of ​​the entire subject, and a position of the maximum binarized region; The X-ray phase imaging apparatus according to claim 9 , wherein the control unit is configured to predict the position of the intensity reduction portion based on a ratio of the areas of the maximum binarized regions and the position of the maximum binarized regions.

11. the feature amount includes a ratio of an area of ​​all the binarized regions to an area of ​​the entire subject, The X-ray phase imaging apparatus according to claim 9 , wherein the control unit is configured to obtain an index value of the mechanical strength of the entire object based on a ratio of an area of ​​all the binarized regions to an area of ​​the entire object.

12. The X-ray phase-shift imaging apparatus according to claim 9 , wherein the control unit is configured to acquire the feature amount based on the binarized region, which is a region having a value greater than a preset threshold value.

13. The X-ray phase imaging apparatus according to claim 12, wherein the control unit is configured to obtain a tendency of bias in the orientation of the fibers within the subject based on the size and number of the binarized regions in the binarized image.

14. 1. An X-ray phase imaging image analysis method for predicting a location where mechanical strength of a subject including fibers is reduced, comprising: imaging the object and a plurality of gratings disposed between the X-ray source and the X-ray detector at a plurality of imaging angles while rotating the object relative to a rotation direction about an irradiation axis direction of the X-ray; generating a plurality of X-ray phase contrast images for each orientation of the subject with respect to the plurality of gratings based on an intensity distribution of X-rays detected by the X-ray detector; acquiring orientation information regarding the orientation of the fibers included in the subject based on the plurality of X-ray phase contrast images; and acquiring a feature quantity related to the mechanical strength of the object based on the acquired orientation information.

15. An X-ray phase imaging image analysis method as described in Claim 14, wherein, in the step of acquiring the feature amount, the feature amount of the direction of action of the force acting on the subject is acquired based on the direction of action of the force and the orientation information of a direction intersecting the direction of action of the force.