JP7452722B2 - Inspection device and image generation method - Google Patents

Description

The present invention relates to an inspection device and an image generation method.

In order to evaluate the strength and durability of materials, tensile tests, bending tests, etc., are widely used to evaluate the load applied to a test piece and the amount of load required to break it. Fatigue tests and durability tests are also widely conducted in which a load corresponding to actual usage conditions is repeatedly applied to a test piece to evaluate the number of repetitions required for the test piece to break.
In addition, in actual products, durability tests are repeated over a long period of time to repeatedly apply a constant load to evaluate whether the final lifespan satisfies the required specifications. A method has also been devised to predict product life through a short test based on changes during the test in combination with analysis such as FEM (finite element method) (for example, see Patent Document 1).

The mechanism by which a test piece breaks down when a load is applied is thought to be that micro voids and cracks are generated inside due to stress, which expand and connect, eventually leading to breakage. Therefore, it is necessary to visualize changes inside the test piece during durability testing, but conventional optical microscopes cannot observe the inside of the test piece, and inspection methods using X-ray fluoroscopy equipment lack resolution. , it is not possible to visualize the minute voids and cracks that are the starting point and root cause of fracture.

High-resolution micro-CT can visualize minute voids and cracks, but it has the following problems.
・One measurement takes a long time, ranging from several tens of minutes to several hours.
- The size of the measurable area becomes extremely narrow when the resolution is increased (for example, in the case of a voxel size of 1 micron, the measurement area is approximately 1 ^mm3 ).
・Since it is necessary to photograph the test piece from multiple directions, the X-ray source and detector are fixed and the test piece is rotated, or the test piece is fixed and the X-ray source and detector are set and rotated. required, which limits the size of the test piece. If the specimen is too large, it will collide with the X-ray source and detector when rotated. Moreover, a large-scale mechanism is required for measurement.
Therefore, it is extremely difficult to perform in situ evaluation while performing a tensile test using micro-CT. However, in order to make products lighter and more compact in the future, it will be necessary to develop new materials that are thinner and lighter, while increasing strength. are required to do so. Specifically, there is a need for a method that can easily and in detail evaluate the starting point of fracture and the progress of voids and cracks at that time and location.

For example, as described in Non-Patent Document 1, if an X-ray source using a synchrotron (with a very strong X-ray dose and high resolution) is used, it is possible to observe the progress of cracks when a load is applied to a test piece. Can be photographed.

Japanese Patent Application Publication No. 2009-20066

Y.-C. Hung et. al., “Fatigue crack growth and load redistribution in Ti/SiC composites observed in situ”, Acta Materialia, vol.57, pp.590-599 (2009)

However, synchrotrons are very large-scale and expensive, and cannot be used frequently for general product development, except for research purposes at universities and the like.

The objective of the present invention is to capture changes inside the subject that cannot be seen with conventional absorption X-ray images when a load is applied to the subject, without using large-scale equipment, in a shorter imaging time and with a wider field of view. The purpose is to obtain and make it possible to observe.

In order to solve the above problems, the inspection device of the present invention includes:
A radiation source, a plurality of gratings, and a radiation detector are provided side by side in the direction of the radiation irradiation axis, and the radiation source irradiates a plastic subject made of resin arranged in the direction of the radiation irradiation axis. Talbot imaging means for generating at least a differential phase image of the subject based on a moiré fringe image obtained by irradiating and imaging;
applying means for applying a load to the subject;
a control means that repeatedly performs control to generate a differential phase image by causing the Talbot photographing means to photograph the subject while applying a load to the subject by the applying means;
a detection means for detecting a change in the differential phase image based on the plurality of differential phase images of the subject generated by the Talbot imaging means;
Equipped with
The Talbot imaging means further generates a small-angle scattering image or an absorption image when generating the differential phase image based on the control of the control means,
A plurality of small-angle scattering images taken by the Talbot photographing means before applying a load to the test object by the applying means and after the test object is fractured by applying a load to the test object by the applying means, differential phase The positions of a plurality of feature points are extracted by analyzing an image or an absorption image, and the position of the subject is determined between the extracted plurality of feature points before applying a load to the subject and by applying a load to the subject. An identification means is provided for identifying an elastically deformed portion and a plastically deformed portion inside the subject based on a comparison of distances after the fracture occurs.
Furthermore, the inspection device of the present invention includes:
A radiation source, a plurality of gratings, and a radiation detector are provided side by side in the direction of the radiation irradiation axis, and the radiation source irradiates a plastic subject made of resin arranged in the direction of the radiation irradiation axis. Talbot imaging means for generating at least a differential phase image of the subject based on a moiré fringe image obtained by irradiating and imaging;
applying means for applying a load to the subject;
a control means that repeatedly performs control to generate a differential phase image by causing the Talbot photographing means to photograph the subject while applying a load to the subject by the applying means;
a detection means for detecting a change in the differential phase image based on the plurality of differential phase images of the subject generated by the Talbot imaging means;
Equipped with
The control means repeatedly performs control to generate a differential phase image by photographing the subject with the Talbot imaging means while applying a load to the subject with the applying means until the subject deteriorates,
From each of the plurality of differential phase images generated, a region where the signal value is equal to or higher than a predetermined threshold is extracted, and the signal intensity, size, and in-plane distribution of the extracted region are determined when the differential phase image is photographed. is stored in a database in association with a value representing the load applied to the subject by the imparting means, and a differential phase image obtained by photographing a new subject by the Talbot photographing means is stored in the database. Estimating means is provided for estimating the degree of deterioration of the new object based on the accumulated information.

Furthermore, the image generation method of the present invention includes:
A radiation source, a plurality of gratings, and a radiation detector are provided side by side in the direction of the radiation irradiation axis, and the radiation source irradiates a plastic subject made of resin arranged in the direction of the radiation irradiation axis. Talbot imaging means for generating at least a differential phase image of the subject based on a moiré fringe image obtained by irradiating and imaging;
applying means for applying a load to the subject;
An image generation method in an inspection device comprising:
Repeatedly performing a process of generating a differential phase image and a small-angle scattering image or an absorption image by causing the Talbot imaging unit to image the subject while applying a load to the subject by the applying unit,
Detecting a change in the differential phase image based on the plurality of differential phase images of the subject generated by the Talbot imaging means,
A plurality of small-angle scattering images taken by the Talbot photographing means before applying a load to the test object by the applying means and after the test object is fractured by applying a load to the test object by the applying means, differential phase The positions of a plurality of feature points are extracted by analyzing an image or an absorption image, and the position of the subject is determined between the extracted plurality of feature points before applying a load to the subject and by applying a load to the subject. Based on a comparison of the distances after the fracture, an elastically deformed portion and a plastically deformed portion within the subject are identified.
Furthermore, the image generation method of the present invention includes:
A radiation source, a plurality of gratings, and a radiation detector are provided side by side in the direction of the radiation irradiation axis, and the radiation source irradiates a plastic subject made of resin arranged in the direction of the radiation irradiation axis. Talbot imaging means for generating at least a differential phase image of the subject based on a moiré fringe image obtained by irradiating and imaging;
applying means for applying a load to the subject;
An image generation method in an inspection device comprising:
Repeatedly performing a process of generating a differential phase image by causing the Talbot imaging unit to image the subject while applying a load to the subject by the applying unit;
Detecting a change in the differential phase image based on the plurality of differential phase images of the subject generated by the Talbot imaging means,
A plurality of differentials generated by repeatedly performing a process of photographing the subject with the Talbot imaging means and generating a differential phase image while applying a load to the subject with the applying means until the subject deteriorates. A region in which the signal value is equal to or greater than a predetermined threshold is extracted from each phase image, and the signal intensity, size, and in-plane distribution of the extracted region are determined by the imparting means when the differential phase image is photographed. Based on the differential phase image obtained by storing the data in a database in association with a value representing the load applied to the specimen and photographing a new specimen with the Talbot imaging means, and the information stored in the database. Then, the degree of deterioration of the new object is estimated.

According to the present invention, changes inside the subject that cannot be seen with conventional absorption X-ray images when a load is applied to the subject can be captured in a wider field of view in a shorter imaging time without using large-scale equipment. It becomes possible to obtain and observe the data.

1 is a diagram showing a configuration example of an inspection device according to a first embodiment; FIG. FIG. 3 is a plan view of a multi-slit. FIG. 2 is a block diagram showing the functional configuration of a controller. FIG. 2 is a diagram explaining the principle of a Talbot interferometer. 4 is a flowchart showing photographing processing A executed by the control unit of FIG. 3 in the first embodiment. It is a graph for explaining stress relaxation. 1 is a diagram showing a test piece used in Example 1. FIG. FIG. 3 is a diagram showing the relationship between the amount of tensile elongation and stress in Example 1. 2 is a diagram in which absorption images, small-angle scattering images, and differential phase images generated in Example 1 are arranged in chronological order. FIG. FIG. 6 is a diagram showing the relationship between the amount of tensile elongation and stress in Example 2. 3 is a diagram in which absorption images, small-angle scattering images, and differential phase images generated in Example 2 are arranged in chronological order. FIG. 3 is a diagram showing a test piece used in Example 3. FIG. FIG. 7 is a diagram showing the relationship between the amount of tensile elongation and stress in Example 3. 3 is a diagram chronologically arranging absorption images, small-angle scattering images, and differential phase images generated in Example 3. FIG. This is a Talbot image of CFRTP. This is a Talbot photograph of an aluminum die-cast part. FIG. 3 is a diagram illustrating a strain distribution image generated in an example of estimating internal stress by image analysis, side by side with a small-angle scattering image. FIG. 6 is a diagram illustrating strain analysis results generated in an example of identifying elastic deformation and plastic deformation side by side with small-angle scattering images. FIG. 3 is a diagram illustrating an example of a method of displaying an acquired image. FIG. 2 is a view from above of a tensile testing machine with a subject set therein. It is a figure showing an example of composition of an inspection device concerning a 2nd embodiment. 4 is a flowchart showing photographing processing B executed by the control unit of FIG. 3 in the second embodiment. FIG. 7 is a diagram in which absorption images, small-angle scattering images, and differential phase images generated in Example 4 are arranged in chronological order.

Embodiments of the present invention will be described below with reference to the drawings.
In the first embodiment, an example will be described in which the load applied to the subject is a load, and in the second embodiment, an example will be explained in which the load applied to the subject is heat.

[First embodiment]
(Configuration of radiography system)
FIG. 1 is a diagram schematically showing an inspection apparatus 100 according to a first embodiment of the present invention.
The inspection apparatus 100 is an apparatus that photographs a subject H such as a test piece while performing a tensile test on the subject H.

As shown in FIG. 1, the inspection device 100 includes a main body 1 and a controller 5.
As shown in FIG. 1, the main body 1 includes a radiation source 11, a first cover unit 120 including a multi-slit 12 and an additional filter/collimator 112, a subject stage 13, a first grating 14, and a second grating 15. , a second cover unit 130 including a radiation detector 16, a support 17, and a base 19. The Talbot-Lau interferometer of the main body 1 is vertical, and the radiation source 11, multi-slit 12, object stage 13, first grating 14, second grating 15, and radiation detector 16 are arranged in this order in the gravitational direction. It is arranged in the z direction. A camera 21 and a mirror 22 are provided between the first cover unit 120 and the second cover unit 130 of the main body 1 . Further, a tensile tester 23 is provided on the subject stage 13.

The multi-slit 12, the subject table 13, the first grating 14, the second grating 15, and the radiation detector 16 are held on the same base 19 and attached to the support 17. The base portion 19 may be configured to be movable in the z direction with respect to the support column 17.
Further, in addition to the base portion 19, a radiation source 11 is attached to the support column 17. The radiation source 11 is held on the support column 17 via a buffer member 17a. The buffer member 17a may be made of any material as long as it can absorb shocks and vibrations, such as elastomer. Since the radiation source 11 generates heat when irradiated with radiation, it is preferable that the buffer member 17a on the side of the radiation source 11 is additionally made of a heat insulating material.

The radiation source 11 includes an X-ray tube, which generates X-rays and irradiates the X-rays in the z direction (gravitational direction). As the X-ray tube, for example, a Coolidge X-ray tube or a rotating anode X-ray tube can be used. Tungsten or molybdenum can be used as the anode.
The focal diameter of the radiation source 11 is preferably 0.03 to 3 (mm), more preferably 0.1 to 1 (mm).
In this embodiment, a case will be described in which imaging is performed using X-rays, but other radiations such as neutron beams, gamma rays, etc. may also be used.

The first cover unit 120 is a unit provided directly below the radiation source 11. As shown in FIG. 1, the first cover unit 120 includes a multi-slit 12, a mounting arm 12b, an additional filter/collimator 112, and the like. Each component of the first cover unit 120 is covered and protected by a cover member.

The multi-slit 12 (G0 grating) is a diffraction grating, and as shown in FIG. 2, a plurality of slits are arranged at predetermined intervals in the x direction orthogonal to the radiation irradiation axis direction (here, the z direction). . The multi-slit 12 is formed of a material such as tungsten, lead, or gold that has a large radiation shielding power, that is, a material that has a high radiation absorption rate, on a substrate made of a material that has a low radiation absorption rate, such as silicon or glass. For example, a resist layer is masked in the form of slits by photolithography, and UV is irradiated to transfer the slit pattern onto the resist layer. A slit structure having the same shape as the pattern is obtained by exposure, and metal is embedded between the slit structures by electroforming to form the multi-slit 12.

The slit period (grating period) of the multi-slit 12 is 1 to 60 (μm). As shown in FIG. 2, the slit period is defined as the distance between adjacent slits. The width of the slit (the length of each slit in the slit period direction (x direction)) is 1 to 60 (%) of the slit period, more preferably 10 to 40 (%). The height of the slit (height in the z direction) is 1 to 1500 (μm), preferably 30 to 1000 (μm). The multi-slit 12 is supported by an attachment arm 12b and attached to the base portion 19.

The additional filter/collimator 112 limits the irradiation area of the X-rays emitted from the radiation source 11 and removes low-energy components that do not contribute to imaging from the X-rays emitted from the radiation source 11. .

As shown in FIG. 1, the second cover unit 130 includes a subject stage 13, a first grating 14, a second grating 15, a moving mechanism 15a, a radiation detector 16, and the like. The upper surface of the second cover unit 130 is the subject stage 13, and by covering the periphery of the subject stage 13 with a cover member, the internal components are protected from damage caused by contact with the subject H or the technician and from intrusion of dust. are doing. Furthermore, since the temperature inside the unit is less susceptible to the influence of outside air, it is possible to reduce fluctuations in the grid positions due to thermal expansion of the first grid 14 and the second grid 15.

The subject stage 13 is a stage on which the subject H is placed.
A tensile testing machine 23 is provided on the subject stage 13, and the subject H is held on the tensile testing machine 23.

The first grating 14 (G1 grating), like the multi-slit 12, is a diffraction grating in which a plurality of slits are arranged in the x direction orthogonal to the z direction, which is the radiation irradiation axis direction. The first lattice 14 can be formed by photolithography using UV in the same way as the multi-slit 12, or it can be formed by deep drilling with fine lines in a silicon substrate using the so-called ICP method to form a lattice structure using only silicon. It may also be a thing. The slit period of the first grating 14 is 1 to 20 (μm). The width of the slit is 20 to 70 (%) of the slit period, preferably 35 to 60 (%). The height of the slit is 1 to 100 (μm).

The second grating 15 (G2 grating), like the multi-slit 12, is a diffraction grating in which a plurality of slits are arranged in the x direction orthogonal to the z direction, which is the radiation irradiation axis direction. The second grating 15 can also be formed by photolithography. The slit period of the second grating 15 is 1 to 20 (μm). The width of the slit is 30 to 70 (%) of the slit period, preferably 35 to 60 (%). The height of the slit is 1 to 100 (μm). A moving mechanism 15a that moves the second grating 15 in the x direction is provided adjacent to the second grating 15. The moving mechanism 15a may have any configuration as long as it can linearly feed the second grating 15 in the x direction by driving a motor or the like.

The radiation detector 16 includes two-dimensionally arranged conversion elements that generate electric signals in response to irradiated radiation, and reads the electric signals generated by the conversion elements as image signals. The pixel size of the radiation detector 16 is 10 to 300 (μm), more preferably 50 to 200 (μm). It is preferable that the radiation detector 16 is fixed in position to the base part 19 so as to be in contact with the second grating 15. This is because as the distance between the second grating 15 and the radiation detector 16 increases, the moiré fringe image obtained by the radiation detector 16 becomes blurred.

As the radiation detector 16, an FPD (Flat Panel Detector) can be used.
There are two types of FPDs; an indirect conversion type in which radiation is converted into an electrical signal by a photoelectric conversion element via a scintillator, and a direct conversion type in which radiation is directly converted into an electrical signal; either of these may be used.
Further, as the radiation detector 16, a radiation detector that has the intensity modulation effect of the second grating 15 may be used. For example, in order to provide a dead area in the scintillator with the same period and width as the slits of the second grating 15, a slit scintillator detector may be used as the radiation detector 16 by digging grooves in the scintillator and forming a grating-like scintillator. (Reference document 1: Simon Rutishauser et al., "Structured scintillator for hard x-ray grating interferometry", APPLIED PHYSICS LETTERS 98, 171107 (2011)). Since the radiation detector 16 with this configuration has both the second grating 15 and the radiation detector 16, there is no need to separately provide the second grating 15. That is, providing the slit scintillator detector is the same as providing the second grating 15 and the radiation detector 16.

The Talbot-Lau interferometer of the main body 1 will be described as being configured to irradiate X-rays from the radiation source 11 provided on the upper side toward the subject H below (so-called vertical type case). However, the present invention is not limited to this, and the configuration may be such that X-rays are irradiated from the radiation source 11 provided on the lower side toward the subject H above. Further, it is also possible to irradiate X-rays in an arbitrary direction, such as in a horizontal direction (in the case of a so-called horizontal type).

The camera 21 is configured with an imaging lens, an imaging element consisting of an image sensor such as a CCD (Charge Coupled Device), an A/D conversion circuit, etc., and uses the imaging element to capture an optical image of the subject H that has passed through the imaging lens in a two-dimensional manner. This is a photographing means that converts the image signal into an image signal and obtains a photographed image representing the external appearance of the subject H. The camera 21 may be one that shoots still images, or may be a video camera that shoots moving images.
The camera 21 may be positioned anywhere as long as the subject H can be photographed, but if it is on the same optical axis as the Talbot-Low interferometer, the photographed image obtained by the camera 21 can be captured by the Talbot-Low interferometer. This is preferable because when comparing the obtained small-angle scattering image or differential phase image, the image can be directly compared without image distortion. In this embodiment, a mirror 22 is arranged on the axis of radiation irradiation by the radiation source 11, and the mirror 22 guides an optical image of the subject H to the imaging lens of the camera 21. The mirror 22 is made of aluminum, glass, or the like and does not shield radiation.

The tensile tester 23 applies a tensile load to the subject H by moving a jig that holds the subject H. The tensile testing machine 23 is configured to pull the subject H from both sides, so that the center of the subject H does not escape from the field of view during the tensile test. The tensile tester 23 functions as a means for applying a load.

As shown in FIG. 3, the controller 5 includes a control section 51, an operation section 52, a display section 53, a communication section 54, and a storage section 55.
The control unit 51 includes a CPU (Central Processing Unit) and a RAM (Random Access Memory).
) etc. The control section 51 is connected to each section of the main body section 1 (for example, the radiation source 11, the radiation detector 16, the moving mechanism 15a, the camera 21, the tensile tester 23, etc.), and controls the operation of each section. Further, the control unit 51 executes various processes including photographing process A, which will be described later, in cooperation with a program stored in the storage unit 55.
The control unit 51 functions as a control means, a distortion distribution calculation means, a highlighting means, an identification means, a display control means, a storage control means, an adjustment means, and an estimation means. Further, it functions as a Talbot imaging means in cooperation with a radiation source, a grating (multi-slit 12, first grating 14, second grating 15), radiation detector 16, and the like.

The operation unit 52 includes a group of keys used for input operations such as exposure switches and imaging conditions, as well as a touch panel configured integrally with a display of a display unit 53, and generates operation signals corresponding to these operations for control. It is output to section 51.
The display section 53 displays an operation screen, the operating status of the main body section 1, etc. on the display according to the display control of the control section 51.

The communication unit 54 includes a communication interface and communicates with external devices on the network.
The storage unit 55 is composed of a non-volatile semiconductor memory, a hard disk, etc., and stores programs executed by the control unit 51 and data necessary for executing the programs.

(Photographed by Talbot interferometer and Talbot-Lau interferometer)
Here, an imaging method using a Talbot interferometer and a Talbot-Lau interferometer will be explained.
As shown in FIG. 4, when the X-rays emitted from the radiation source 11 pass through the first grating 14, the transmitted X-rays form images at regular intervals in the z direction. This image is called a self-image, and the phenomenon in which a self-image is formed is called the Talbot effect. A second grating 15 is placed at a position where the self-image is formed and is generally parallel to the self-image, and a moire fringe image (indicated by Mo in FIG. 4) is obtained by X-rays transmitted through the second grating 15. That is, the first grating 14 forms a periodic pattern, and the second grating 15 converts the periodic pattern into moire fringes. When the subject H exists between the radiation source 11 and the first grating 14, the phase of the X-rays is shifted by the subject H, so the moire fringes on the moire fringe image are disturbed around the edges of the subject H as shown in FIG. . This disturbance in the moire fringe can be detected by processing the moire fringe image, and the subject image can be converted into an image. This is the principle of the Talbot interferometer.

In the main body 1, a multi-slit 12 is arranged at a position close to the radiation source 11 between the radiation source 11 and the first grating 14, and X-ray imaging is performed using a Talbot-Lau interferometer. The Talbot interferometer is based on the premise that the radiation source 11 is an ideal point source, but in actual imaging, a focal point with a somewhat large focal diameter is used, so the multi-slit 12 allows X This produces the effect of being irradiated with a ray of light. This is an X-ray imaging method using a Talbot-Lau interferometer, and even when the focal diameter is large to some extent, it is possible to obtain the same Talbot effect as with the Talbot interferometer.

In the main body 1 of this embodiment, a moiré fringe image necessary for generating a reconstructed image of the subject H is photographed using a fringe scanning method. Fringe scanning generally refers to scanning any one (in this embodiment, the second grating 15) or two of the gratings (multi-slit 12, first grating 14, second grating 15). The slit is moved relatively in the periodic direction (x direction) and taken M times (M is a positive integer, M>2 for absorption images, M>3 for differential phase images and small-angle scattering images) (takes M steps). This refers to acquiring M moiré fringe images necessary to generate a reconstructed image. Specifically, assuming that the slit period of the grating to be moved is d (μm), the grating is repeatedly moved in the slit period direction by d/M (μm) and photographed to obtain M moiré fringe images. .

Reconstructed images generated based on moire fringe images include small-angle scattering images, differential phase images, and absorption images.
A small-angle scattering image is an image of X-ray scattering in a microstructure, and the larger the X-ray scattering, the larger the signal value. Small-angle scattering images can capture microstructure aggregates of several micrometers to several tens of micrometers, which is smaller than the pixel size.
The differential phase image is an image of the refraction of X-rays by the subject, and the greater the refraction of the X-rays, the greater the signal value. In absorption images, the sensitivity decreases for lighter elements, but differential phase images maintain high sensitivity even for light elements, making it possible to capture changes in substances that are difficult to detect with absorption images.
An absorption image is an image of absorption of X-rays by a subject, and is an image equivalent to a conventional simple X-ray image.

(Operation of inspection device 100)
Next, the operation of the inspection device 100 will be explained.
FIG. 5 is a flowchart showing the photographing process A executed in collaboration with the control unit 51 of the inspection apparatus 100 and the program stored in the storage unit 55. The photographing process A is a process in which the load (tensile load) or tensile length applied to the subject H by the tensile tester 23 is changed in stages, and the subject H is photographed at each stage (referred to as a tensile step). It is. In the photographing process A, the subject H is set in the tensile tester 23, and the test conditions (for example, the load or tensile length to be applied to the subject H for each photographing (the treatment for holding the subject H in the tensile tester 23) are set using the operation unit 52. The setting value of the moving distance of the clamp, which is a tool, etc.) is input and the photographing execution is instructed.In this embodiment, the subject H is not set in the tensile testing machine 23 before the photographing process A starts. state, or with the subject H and the tensile testing machine 23 removed from the subject stage 13, the second grid 15 is moved to create M moire fringe images (referred to as BG (Back Ground) moire fringe images) without the subject ( For example, it is assumed that four images are acquired and stored in the storage unit 55.

When the photographing process A is started, the control unit 51 photographs the subject H before applying a load using the tensile tester 23 .
That is, the control unit 51 causes the camera 21 to photograph the subject H, and obtains a photographed image (step S1). The photographed image is accompanied by an image number, photographing conditions, photographing date and time, etc. for identifying the image.
Next, the control unit 51 controls the radiation source 11, the moving mechanism 15a, the radiation detector 16, etc., and performs imaging (referred to as Talbot imaging) to obtain a moiré fringe image using the above-mentioned Talbot effect. In this embodiment, M moire fringe images with a subject (referred to as subject moire fringe images) are acquired by a fringe scanning method while moving the grating (second grating 15 in this embodiment) in the slit period direction. . Then, reconstructed images (small-angle scattering image, differential phase image, absorption image) are generated based on the BG striped moire image and the subject moire fringe image acquired in advance (step S2).

To generate a reconstructed image, for example, first, offset correction processing, gain correction processing, defective pixel correction processing, X-ray intensity fluctuation correction, etc. are performed on the subject moire fringe image. Next, a reconstructed image is generated based on the corrected subject moire fringe image and the BG moire fringe image for generating the constituent images. The absorption image is generated by logarithmically converting the transmittance image, which is generated by dividing the summation image of M subject moiré fringe images by the summation image of M BG moiré fringe images. The differential phase image is created by calculating the phase of the moire fringe using the principle of the fringe scanning method for each of the subject moire fringe image and the BG moire fringe image, thereby generating a differential phase image with the subject and a differential phase image without the subject, respectively. However, it is generated by subtracting the differential phase image without the subject from the generated differential phase image with the subject. The small-angle scattering image is created by calculating the visibility of the moire fringe using the principle of the fringe scanning method for each of the subject moire fringe image and the BG moire fringe image (Visibility = amplitude ÷ average value). It is generated by generating each small-angle scattering image without a subject and dividing the generated small-angle scattering image with a subject by the small-angle scattering image without a subject (Reference document 2; Timm Weitkamp, Ana Diazand, Christian David, franz Pfeiffer and Marco Stampanoni, Peter Cloetens and Eric Ziegler,X-ray Phase Imaging with a grating interferometer,OPTICSEXPRESS, Vol.13, No.16,6296-6004(2005), Reference 3; Yoshio Suzuki and Tadashi Hattori, Phase Tomography by X-ray Talbot Interferometry for Biological Imaging, Japanese Journal of Applied Physics, Vol.45, No.6A, 2006, pp.5254-5262 (2006), Reference 4; F. Pfeiffer , M.Bech, O.Bunk, P.Kraft, EFEikenberry, CH.Broennimann, C.Grunzweig, and C.David, Hard-X-ray dark-field imaging using a grating interferometer, nature materials Vol.7, 134- 137 (2008)).
The reconstructed image is accompanied by an image number for identifying the image, inspection conditions, photography conditions for Talbot photography, photography date and time, and the like.

Note that the order of steps S1 and S2 may be reversed or may be performed simultaneously. The purpose of acquiring a photographed image with the camera 21 is to acquire an image similar to that obtained by visually observing the subject H, that is, an image that visualizes the external appearance of the subject H, and thereby to obtain a small-angle scattering image obtained by Talbot photography or a small-angle scattering image obtained by Talbot photography. This is for comparison with the differential phase image, and it is preferable to take the image at the same timing as the Talbot image as much as possible.
Further, the camera 21 may take still images or videos. When shooting a moving image, it is preferable that a signal is recorded at the same time so that it can be seen at which timing in the moving image Talbot photography was performed. For example, an indicator that emits light during Talbot shooting may be placed within the field of view of the camera 21 and photographed at the same time as the subject H, or a timestamp at the time of video recording and a Talbot shooting attached to the reconstructed image may be attached to the video. Various methods can be considered, such as comparing the times of Furthermore, instead of photographing with the camera 21, the absorption image generated based on Talbot photography in step S2 may be used as an image for comparison with the small-angle scattering image or the differential phase image. In this case, step S1 can be omitted. Further, images for comparison may be obtained using a plurality of means. For example, if a thermography device (temperature distribution image acquisition means) is separately provided and the temperature of the subject H is changed, the temperature distribution images of the subject H may be simultaneously acquired by the thermography device.

Next, the control unit 51 uses the photographed image acquired in step S1 (including the temperature distribution image when a temperature distribution image is acquired) and the reconstructed image acquired in step S2 on the tensile tester 23 during photographing in steps S1 and S2. This is stored in the storage unit 55 in association with the value of the load applied to the subject H (step S3). Note that the value of the load may be the value of the load itself, or the moving distance (corresponding to the tensile length and tensile elongation amount) of the clamp, which is a jig that holds the subject H in the tensile tester 23. Or both. Alternatively, it may be a stress value.

Next, the control unit 51 determines whether the conditions for ending the process are satisfied (step S4). For example, the conditions for terminating the process are as follows:
・The load of the tensile tester 23 has reached the target value. ・The tensile length of the tensile tester 23 has reached the target value. ・The object H has broken. (e.g., it has come off the machine 23), and the test has been completed for a predetermined number of times.

Whether or not the subject H has been broken can be determined by, for example, whether or not the user has performed a predetermined operation on the operation unit 52 indicating that a break has been detected (for example, by pressing a button to press when a break has been detected). The determination may be made based on whether the button is pressed or not, or the determination may be made by analyzing a reconstructed image generated based on Talbot photography. Alternatively, the occurrence of breakage may be determined based on the fact that the load does not increase or decreases even after being pulled a certain distance using the tensile tester 23.
Further, whether or not an abnormality has occurred can be determined by, for example, whether or not the user has performed a predetermined operation on the operation unit 52 indicating that an abnormality has been detected (for example, a button to be pressed when an abnormality is detected). The determination may be made based on whether the button is pressed or not, or the determination may be made by analyzing a reconstructed image generated based on Talbot photography. Alternatively, it may be determined that an abnormality has occurred when the load on the tensile tester 23 decreases and becomes less than a set value.

If it is determined that the processing termination conditions are not satisfied (step S4; NO), the control unit 51 changes the load or tensile length settings of the tensile tester 23 based on the inspection conditions, and The load applied to the subject H is changed by (step S5).

Next, the control unit 51 determines whether the load or tensile length of the tensile tester 23 has reached a set value (step S6).
Here, the tensile testing machine 23 is equipped with a force sensor such as a load cell that detects force, and measures the load applied to the subject H by this force sensor and outputs the measured load to the control section 51. The tensile testing machine 23 also includes a sensor that measures the moving distance of a clamp, which is a jig for holding the subject H, and outputs the moving distance measured by this sensor to the control unit 51. The control unit 51 makes the determination in step S6 based on the load and movement distance measured by these sensors.

If the tensile testing machine 23 determines that the load or tensile length applied to the subject H does not reach the set value (step S6; NO), the control unit 51 waits until the load or tensile length reaches the set value. do.
If it is determined that the load or tensile length applied to the subject H by the tensile testing machine 23 has reached the set value (step S6; YES), the control unit 51 moves to step S7.
In addition, when setting the set value of the tensile tester 23 by load, the tensile length can be set so that it stops after reaching the set value, and the tensile length is set so that the load of the set value is always maintained even after reaching the set value. There are two types of settings that you keep tweaking. In the latter case, if the object H has a large creep phenomenon (a phenomenon in which distortion increases over time when sustained stress acts on an object), the tensile length will gradually increase. In this case, the deformation of the subject H will become larger and larger, that is, it will continue to stretch, and the image will become blurred during Talbot photography, or in severe cases, the image may not be able to be reconstructed and photography may fail. Therefore, when combined with Talbot imaging, it is preferable to use a setting that stops the movement of the clamp of the tensile tester 23 when the load reaches a set value.

In step S7, the control unit 51 determines whether the temperature of the tube of the radiation source 11 is lower than a predetermined standard (step S7).
If it is determined that the temperature of the tube of the radiation source 11 is not lower than the predetermined standard (step S7; NO), the control unit 51 determines that the temperature of the tube of the radiation source 11 is lower than the predetermined standard. Wait until.
If the temperature of the anode inside the tube of the radiation source 11 rises as a result of irradiating X-rays with the radiation source 11, it is necessary to wait for the next X-ray irradiation until it is cooled down and the temperature drops below the standard value. be. Whether or not the temperature of the tube of the radiation source 11 is lower than a predetermined standard may be determined, for example, by the value of a thermometer installed in the radiation source 11, or by determining whether the temperature of the tube of the radiation source 11 is lower than a predetermined standard. The temperature of the tube may be predicted and determined based on time. In addition, if the internal temperature does not rise even if X-rays are irradiated for a long time, such as with a radiation source 11 that has a high cooling capacity or can irradiate X-rays continuously, this method may be used if there is no need to wait for cooling. No process required.

When determining that the temperature of the tube of the radiation source 11 is lower than a predetermined standard (step S7; YES), the control unit 51 determines whether the deformation of the subject H has stabilized (step S8).
Here, even if the application of load (movement of the clamp) by the tensile tester 23 is completed as set, in reality, the stress in the subject H gradually decreases due to stress relaxation. FIG. 6 shows the state of stress relaxation. In FIG. 6, the horizontal axis represents time and the vertical axis represents stress. The setting value of the tensile tester 23 is changed at the timing indicated by the arrow, and the stress on the subject H is increased. Although the application of load (movement of the clamp) by the tensile tester 23 has ended at the time of the local peak, it can be seen that the stress gradually decreases thereafter. This indicates that although the tensile tester 23 is not moving, the stress is decreasing as a result of the subject H gradually stretching. At this time, the subject H is gradually deforming, and Talbot photography is performed at the timing when the deformation due to this stress relaxation is large (≒ the timing when the stress is greatly reduced; the timing when the slope of the graph in Figure 6 is large). Even if you do so, the image will be blurry or you will fail to capture the image. Therefore, it can be determined that the deformation of the subject H is stable (≒changes in stress are small or saturated; for example, the absolute value of the slope of the graph in Figure 6 is less than a predetermined threshold). It is desirable to confirm this using the image taken by the camera 21, and then proceed to the next step, which is camera photography and Talbot photography.
Note that the stress (N/m ² =Pa) can be calculated from the load (N) output from the tensile tester 23 and the cross-sectional area of the subject H.

If it is determined that the deformation of the subject H is not stable (step S8; NO), the control unit 51 waits until the deformation of the subject H becomes stable.
If it is determined that the deformation of the subject H has stabilized (step S8; YES), the control unit 51 returns to step S1 and performs imaging.
The control unit 51 repeatedly executes the above-described steps until the end condition is satisfied, and ends the photographing process A when it is determined that the end condition is satisfied (step S4; YES).

In order to verify the effectiveness of the first embodiment, (Example 1) to (Example 3) were photographed.
In (Example 1) to (Example 3), Talbot photography is performed in the inspection apparatus 100 while performing a tensile test using a test piece as the subject H, and from the obtained reconstructed image, the subject H is photographed during the tensile test. We evaluated how microcracks and the like grow inside the steel. Specifically, the subject H is set in the tensile testing machine 23, the photographing process A in FIG. 5 is executed, a tensile load is applied to the subject H, and when the deformation is stabilized, Talbot photography is performed to generate a reconstructed image. The process was repeated multiple times. Note that step S1 in FIG. 5 was omitted and an absorption image was used for comparison.
As the tensile tester 23, a small tensile tester manufactured by UK DEBEN was used. The tensile testing machine used was designed to pull the subject H from both sides. As the subject H, we used ABS resin made into the shape of a dumbbell using a 3D printer. (Example 1) to (Example 3) differ in the test pieces used and testing conditions (load, etc.). Each example will be described below.

(Example 1)
A test piece was produced using ABS (Acrylonitrile Butadiene Styrene) resin using a 3D printer, and Talbot photography was performed while performing a tensile test using this as a subject H in the procedure of photography process A.
FIG. 7 shows the shape (dimensions) of the test piece. The thickness is 3 mm. Further, FIG. 8 shows a graph of the amount of tensile elongation and stress of the subject H in the tensile test in Example 1. FIG. 9 shows an absorption image, a small-angle scattering image, and a differential phase image obtained by Talbot imaging in Example 1, arranged in chronological order.

As shown in Figure 9, in the absorption image equivalent to a general X-ray image, almost no change is seen up to the stage of crack generation (5) or rupture (6). In the small-angle scattering image, it can be seen that at the stage (2) before the fracture occurs, a plurality of white streaks are seen at the left and right end portions of the subject H, as shown by the arrows. Moreover, by increasing the tensile length as in (3) and (4), it can be seen that the white streaks further extend from the ends to the inside, and that new white streaks appear. The white area (high signal area) in the small-angle scattering image means that the scattering is large compared to the surrounding area. It is thought that it captures the (3)→(4)→(5) As the amount of tensile elongation increases, the whiteness of the white region in the small-angle scattering image increases (signal intensity increases). This indicates that the cracks and voids have become larger and the scattering has become stronger even at the same location, and it can be seen that the degree of deterioration can be determined by observing the small-angle scattering image. At stage (4), the crack at the lower left of the subject H is becoming visible in the absorption image, but the small-angle scattering image also captures deterioration in other parts, demonstrating the effectiveness of the small-angle scattering image. Finally, as shown in (5), in the small-angle scattering image, it can be seen that the white streaks extending from the upper and lower ends of the subject H are connected, and as shown in (6), it appears that the white streaks are broken. The differential phase image also shows a slight crack, as shown by the arrow, but it is not as noticeable as the small-angle scattering image.
In Example 1, the deterioration of the subject H is captured from the stage before fracture using small-angle scattering images unique to Talbot imaging, and the small-angle scattering images were obtained by performing Talbot imaging while performing a tensile test. It was confirmed that by acquiring this information, it is possible to obtain useful information for studying the mechanism of material deterioration and for considering stronger materials and structures.
Furthermore, looking at the small-angle scattering image after the fracture (6), there are multiple locations where the signal is strong other than the fracture location, and although fracture has not yet occurred in these locations, it is thought that deterioration is progressing inside. That is, it has been confirmed that by observing the small-angle scattering image after the fracture, the user can also recognize which part of the subject H has deteriorated in addition to the fracture.

(Example 2)
A test piece was produced using a 3D printer using PLA (polylactic acid) resin, and Talbot photography was performed using this as a subject H while performing a tensile test in the procedure of photography process A. The shape (dimensions) of the subject H is similar to that shown in FIG. FIG. 10 shows a graph of the amount of tensile elongation and stress of the subject H in the tensile test in Example 2. FIG. 11 shows an absorption image, a small-angle scattering image, and a differential phase image obtained by Talbot imaging in Example 2, arranged in chronological order.

As shown in FIG. 11, similar to Example 1, in the absorption image, which is a general In the scattering image, a plurality of white streaks are visible at the upper and lower ends of the subject H from the previous stages (3) and (4) (see the arrows in FIG. 3). Microcracks are thought to have occurred in these white streaks, and it can be seen that the small-angle scattering image captures the onset of deterioration at an earlier stage than the absorption image. Furthermore, in the small-angle scattering image, it can be seen that as the amount of tensile elongation increases (4) → (5) → (6) → (7), white streaks develop and breakage occurs. Furthermore, in the small-angle scattering image (8) after the fracture, white regions can be seen in areas other than the fracture location, and it is thought that deterioration has progressed in areas other than the fracture location.
In other words, even for the object H of Example 2, which is made of a different material from Example 1, the small-angle scattering image unique to Talbot photography captures the deterioration of the object H even before it breaks, and the tensile test It was confirmed that by performing Talbot imaging and acquiring small-angle scattering images while performing this, it is possible to obtain useful information for studying the mechanism of material deterioration and for studying stronger materials and structures. Furthermore, it has been confirmed that by observing the small-angle scattering image after the fracture, the user can also recognize which part of the subject H has deteriorated in addition to the fracture.

(Example 3)
A test piece was prepared from a CFRP (Carbon Fiber Reinforced Plastic) plate (thickness: 1 mm), and Talbot photography was performed while performing a tensile test using this as a subject H.
FIG. 12 shows the shape (dimensions) of the test piece. The thickness is 1 mm. Further, FIG. 13 shows a graph of the tensile elongation and stress of the test piece in the tensile test in Example 3. FIG. 14 shows an absorption image, a small-angle scattering image, and a differential phase image obtained by Talbot imaging in Example 3, arranged in chronological order.

As shown in FIG. 14, similar to Examples 1 and 2, the absorption image shows no change in the image up to the stage (8) when rupture occurs, whereas the small-angle scattering image shows the state before rupture. You can see that there are cracks starting from the stage. For example, looking at the small-angle scattering image (2), white vertical streaks appear in the area indicated by the arrow, which is thought to indicate microcracks. In addition, as the tensile elongation amount increases from (3) to (4), the number of white vertical streaks on the test piece increases, and furthermore, as shown by the arrow in (5), not only the thinly shaved part of the test piece but also White vertical stripes also occur in the wide portions, and their number increases in (6), eventually leading to breakage. Even in the small-angle scattering image after the fracture (8), white streaks remain, and although such a location has not fractured, it is considered to be deteriorated and weak in strength.
In other words, even for the test piece of Example 3, which is made of a different material from Examples 1 and 2, the small-angle scattering image unique to Talbot photography captures the deterioration of the inside of the object H even before it breaks. Therefore, by performing Talbot imaging and acquiring small-angle scattering images while performing a tensile test, it is possible to obtain useful information for studying the mechanism of material deterioration and for studying stronger materials and structures. confirmed. Furthermore, it was confirmed that by observing the small-angle scattering image after the fracture, the user can also recognize which parts of the test piece are degraded in addition to the fracture part.

As described above, according to the configuration and operation of the inspection device 100 of the first embodiment, it is possible to detect images that are not visible in conventional absorption X-ray images when a load is applied to the subject H, without using a large-scale device. This makes it possible to capture and observe changes inside a subject with a wider field of view in a shorter imaging time.

Modifications of the first embodiment will be described below.

(Internal stress estimation by image analysis)
The control unit 51 of the inspection device 100 analyzes a series of photographed images or reconstructed images (absorption images, small-angle scattering images, differential phase images) obtained in the photographing process A of the first embodiment, and detects characteristic By extracting multiple points and applying a load to the object H, the strength of the stress generated inside the object and its distribution can be calculated and quantified from the change in the distance between the feature points, and furthermore, it can be converted into an image. It may be displayed on the display section 53 by doing so.

For example, in the case of Example 2, the control unit 51 controls the position of each intersection of the mesh patterns seen in each of the plurality of absorption images, small-angle scattering images, or differential phase images shown in FIG. The positions of the white streaks that are thought to reflect the microcracks captured in the image are extracted as feature points, digitized in each image (for example, coordinate information of the position is obtained), and the distance between each feature point is calculated. Next, by calculating the change in the relative distance between each feature point at each tension step and before the tension, or at the previous step (one or more before), the elongation inside the object H at each tension step is calculated. Quantify the size of the amount. This amount of expansion corresponds to the amount of distortion inside the subject H. Since the amount of strain corresponds to the stress applied to that part, the amount of strain inside the subject H can be estimated as internal stress. Alternatively, the relationship between the elongation and stress of the material of the subject H that was measured separately or obtained from a material manufacturer is stored in advance in the storage unit 55, and the elongation calculated from the image and the relationship stored in the storage unit 55 are stored in advance. The internal stress between each point of the subject H may be estimated based on the relationship between the amount of elongation and the stress. Based on the distribution of internal stress among the feature points of the subject H estimated in this way, the control unit 51 can specify in which part the internal stress is strongly generated. In addition, by comparing the internal stress distribution of object H with the simulation results of a CAD model, we can determine the reliability of the design, how much stress is required to generate microcracks, and the stress at the time of fracture. can be analyzed.

The above calculation may be performed using only images of some tensile steps out of a series of reconstructed images obtained in the tensile test. For example, in the case of the image shown in FIG. 11, the internal stress distribution may be calculated using only (1), (3), (5), and (7) before tension.
Alternatively, a 3D image may be obtained by rotating either the subject H or the inspection device 100 and performing Talbot imaging (Talbot CT imaging) from multiple angles, and the above calculation may be performed based on the 3D image. . In that case, it is possible to obtain a three-dimensional distribution of the amount of strain (stress) instead of a two-dimensional in-plane distribution, and it becomes possible to analyze the fracture mechanism and compare it with simulation results in more detail.
As a method of displaying the above calculation results, in addition to displaying numerical data, a strain distribution image or a stress distribution image may be created in which the magnitude of strain and stress is indicated by color or arrow. Then, the strain distribution image and the stress distribution image may be displayed superimposed on the photographed image and the reconstructed image acquired by the camera 21. In the strain distribution image or the stress distribution image, locations with large numerical data of the amount of strain may be highlighted by annotation or the like.

As the reconstructed image to be analyzed above, for example, as shown in FIG. 15, a reconstructed image obtained by Talbot photography of a subject H including fibers may be used. FIG. 15 is a diagram showing a reconstructed image obtained by Talbot imaging of CFRTP (Carbon Fiber Reinforced Thermo Plastics). In FIG. 15, (a) is an absorption image, (b) is a differential phase image, and (c) is a small-angle scattering image. As shown in FIGS. 15(a) to (c), it can be seen that internal fibers that cannot be seen in the absorption image can be visualized in the differential phase image and the small-angle scattering image. Multiple characteristic points of the fiber are extracted from such differential phase images and small-angle scattering images in which the internal fibers are visualized, and as described above, between each characteristic point of each tension step and the step before or before tension. By calculating the change in the relative distance of and displaying the calculation result, it is possible to visualize the amount of strain inside the subject H at each pulling step. Although the image shown in FIG. 15 is the result of 2D imaging, a 3D image is obtained by performing Talbot imaging of the object H from multiple directions (Talbot CT imaging), and the amount of distortion inside the object H is measured in 3D. You can also ask for it. The value of the amount of strain ≒ stress of each acquired feature point is determined by the direction and length of the arrow corresponding to the amount of strain and stress, on the 2D image or 3D image obtained by a series of shots such as camera shooting or Talbot shooting. A strain distribution image or a stress distribution image may be created and displayed by superimposing colors or combinations thereof. In the strain distribution image or the stress distribution image, locations with large numerical data of the amount of strain may be highlighted by annotation or the like.

Furthermore, when a subject H with internal microvoids is subjected to Talbot imaging, signals that are thought to reflect internal microvoids that cannot be seen in absorption images are visualized in small-angle scattering images and differential phase images. FIG. 16 shows images taken by Talbot imaging of two aluminum die-cast parts side by side, in which (a) is an absorption image, (b) is a differential phase image, and (c) is a small-angle scattering image. In FIGS. 16(b) and 16(c), signals thought to reflect minute microvoids, which are not captured in the absorption image in FIG. 16(a), are captured. Therefore, we extracted multiple feature points using signal points that are thought to reflect microvoids in differential phase images and small-angle scattering images, calculated changes in the relative distance between each feature point, and calculated the calculation results. May be displayed. This makes it possible to visualize the amount of distortion inside the subject. In this case, similarly, a 3D image may be acquired by performing Talbot imaging of the subject H from a plurality of directions (Talbo CT imaging), and the amount of distortion inside the subject H may be determined in three dimensions. In addition, the value of the amount of strain ≒ stress for each feature point obtained can be determined by the direction and length of the arrow corresponding to the amount of strain and stress on the 2D image or 3D image obtained by a series of shootings such as camera shooting or Talbot shooting. A strain distribution image or a stress distribution image may be created and displayed by superimposing color, color, or a combination thereof. In a strain distribution image or a stress distribution image, a portion where the numerical data of the amount of strain is large may be highlighted by annotation or the like.

(Example of internal stress estimation using image analysis)
Here, using the small-angle scattering images (1) to (4) shown in FIG. 11 obtained in Example 2, the internal stress was estimated by the image analysis described above. The specific processing is as follows.
・First, each of the small-angle scattering images (1) to (4) in Figure 11 is processed using image processing software (Image-Pro Plus, manufactured by Media Cybernetics), and feature points (here, mesh The coordinates of the center of gravity of the black area surrounded by are extracted. At that time, we specified the contrast and brightness of the image, the pixel value threshold at the time of extraction, the shape of the feature points to be extracted, etc. so that the feature points could be extracted correctly.
・Next, calculate the distance between the feature points in the small-angle scattering images (1) to (4), and compare the distance between each feature point in (2) to (4) with that in (1) before tensioning. The amount of change (change in relative distance) was calculated using (Equation 1).
(Distance between feature points after tension - Distance between feature points before tension)/Distance between feature points before tension... (Formula 1)
Here, the distance between the feature points changes because the feature points are moved by pulling the subject H. That is, the value of (Equation 1) corresponds to the amount of distortion between each feature point inside the subject due to tension.
- Next, an image (strain distribution image) was created in which the amount of distortion was displayed in the corresponding gray scale for each location within the subject H.

FIG. 17 is a diagram showing each of the small-angle scattering images (1) to (4) in FIG. 11 side by side with the strain distribution images corresponding to (2) to (4) generated by the above image analysis. Note that a scale bar indicating the correspondence between the amount of distortion and the gray scale is displayed on the distortion distribution image.
The strain distribution image shown in FIG. 17 shows shading, and it can be seen that the amount of strain differs from place to place. Since the magnitude of strain corresponds to the stress applied to that part, the strain distribution image can also be considered to be a stress distribution image that visualizes the stress distribution. As the tensile elongation amount increases (2) → (3) → (4), it can be seen that the absolute value of strain increases as the maximum value of the lower scale bar increases. It can be seen that the areas with strong distortion (near the white areas in the strain distribution image) and the areas where white streaks appear in the small-angle scattering image (locations where microcracks are thought to have occurred) roughly correspond. You can check it.

From the above, the image analysis described above makes it possible to visualize what kind of strain distribution (stress distribution) occurs inside the object H when microcracks occur, which is useful when considering the fracture mechanism. It was confirmed that the information could be obtained.
In the above embodiment, the small-angle scattering image and the strain distribution are displayed separately, but they may be displayed in an overlapping manner, or may be displayed in color or with arrows in addition to gradation.

(Visualization of orientation state)
By analyzing multiple images taken with Talbot while changing the relative angle between the object H, which contains fibrous materials, and the gratings (multi-slit 12, first grating 14, and second grating 15), the object H It is known that the internal fiber orientation can be visualized.
Therefore, for example, the inspection apparatus 100 includes a rotation mechanism (for example, a rotation stage, etc.) that rotates the tensile tester 23 around the radiation irradiation axis (that is, rotates the subject H set in the tensile tester 23). . Alternatively, a mechanism is provided in which the tensile tester 23 is fixed and the entire inspection apparatus 100 except the tensile tester 23 is rotated around the radiation irradiation axis. Then, in each tensile step of the tensile tester 23 in the above-described photographing process A, the control unit 51 controls the rotation mechanism to rotate the subject H or the inspection device 100 (grid) multiple times, for example, between the grid and the subject. Images are taken three times at relative angles of 0 degrees, 60 degrees, and 120 degrees, and the images are analyzed. For example, in differential phase images and small-angle scattering images, substances oriented in the direction parallel to the slit extending direction (y direction) of the grating are represented by strong signals, but substances oriented in the direction perpendicular to the slit extending direction of the grating are represented by strong signals. A characteristic of these substances is that they are represented by weak signals. Therefore, the signal value of a pixel representing the same part of the subject changes depending on the orientation of the subject H with respect to the grid at the time of photographing. Therefore, we analyze differential phase images or small-angle scattering images obtained by photographing multiple times while changing the relative angle of the subject H to the grid, and the signal value peaks ( By determining the relative angle that is the maximum), it is possible to visualize the orientation direction of fibers, etc. included in the subject H.
In this way, by analyzing the images obtained by performing multiple Talbot shots while changing the relative angle between the subject H and the grid at each tension step while performing a tension test, we were able to detect the internal fibers during tension. It is possible to visualize how the state of the fibers is changing, the occurrence and progress of microcracks, and even the state of the fibers, making it possible to obtain data that is useful for material and device development. .

(Identification of elastic deformation and plastic deformation)
The control unit 51 may analyze the image acquired by the photographing process A and identify the portion where elastic deformation has occurred and the portion where plastic deformation has occurred inside the subject.
In this case, the image before the tensile test (for example, any of the reconstructed images in Example 2 (1)) and the image after the fracture (for example, any of the reconstructed images in Example 2 (8)) compare. If the distance between the feature points is almost the same in (1) and (8) as explained in the above (internal stress estimation by image analysis), the original length is This means that the part (between the feature points) is undergoing elastic deformation internally, which means that phenomena such as slipping and destruction have not occurred.
On the other hand, if the distance between the feature points is different between the image before the tensile test and the image after the fracture, even if the stress becomes zero after the tensile test, the length has not returned to its original length, that is, it is plastically deformed. This means that a phenomenon such as slipping or destruction is occurring inside that part.
By performing the above comparison for each feature point within the subject H, it is possible to obtain the distribution of elastically deformed portions and plastically deformed portions. Then, for example, the elastically deformed portions and plastically deformed portions are displayed in different colors on the Talbot-photographed (or camera-photographed) image to visualize the elastically deformed portions and plastically deformed portions. be able to. As a result, it is possible to know in more detail how the subject H is deformed in the plane (whether it is elastically deformed or plastically deformed) through a series of tests.
Regarding the above-mentioned identification of elastic deformation and plastic deformation, it is not limited to 2-dimensional images, but 3D images are acquired by Talbot imaging the subject H from multiple directions (Talbot CT imaging), and based on the 3D images. It is also possible to do so. This makes it possible to spatially resolve the thickness direction as well, making it possible to know the three-dimensional spatial distribution of elastically deformed regions and plastically deformed regions.

(Example of identification of elastic deformation and plastic deformation)
Here, using the small-angle scattering images (1) and (8) shown in FIG. 11 obtained in Example 2, elastic deformation and plastic deformation inside the subject H were distinguished by the above analysis. The specific processing is as follows.
- First, the small-angle scattering images in (1) and (8) in Figure 11 are processed using image processing software (Image-Pro Plus, manufactured by Media Cybernetics), and feature points (here, mesh The coordinates of the center of gravity of the black area surrounded by are extracted. At that time, we specified the contrast and brightness of the image, the pixel value threshold at the time of extraction, the shape of the feature points to be extracted, etc. so that the feature points could be extracted correctly.
・Next, calculate the distance between the feature points in each small-angle scattering image of (1) and (8), and compare the distance between each feature point of (8) after rupture with that of (1) before tension. The amount of change (change in relative distance) was calculated using the above (Equation 1). Here, the distance between the feature points changes because the feature points are moved by pulling the subject H. That is, the value of (Equation 1) corresponds to the amount of distortion of the subject H due to tension.
- Next, an image (strain distribution image) was created in which the amount of distortion was displayed in the corresponding gray scale for each location within the subject H.

FIG. 18 is a diagram illustrating the small-angle scattering images (1) and (8) of FIG. 11 side by side with the strain distribution image generated by the above-described identification process. Note that a scale bar indicating the correspondence between the amount of distortion and the shade of the gray scale is displayed on the distortion distribution image. Further, since the subject H is divided into two by the fracture, the strain distribution image, which is the analysis result of the amount of strain, is also divided into two.
When an elastically deformed part breaks and the stress becomes zero, it returns to its original state (just like a piece of rubber that is stretched returns to its original state when you release your hand), and the amount of strain is close to zero. Becomes a value. On the other hand, a plastically deformed portion does not return to its original state even if the stress becomes zero, so the amount of strain does not return to zero even after rupture.

The strain distribution image shown in FIG. 18 shows shading, and it can be seen that the amount of strain differs from place to place. In FIG. 18, the amount of strain in the portion A is large because of cracks, and naturally this portion is plastically deformed. In addition, portions B, C, and D also have relatively large amounts of strain, and are considered to be plastically deformed. On the other hand, the portions E to G have a small amount of strain and are considered to be likely to be elastically deformed.
It can be seen that the areas with strong distortion (near the white areas in the image) and the areas where white streaks appear due to small-angle scattering (locations where microcracks are thought to have occurred) roughly correspond.

From the above, by analyzing the small-angle scattering images before tension and after fracture, it is possible to visualize what kind of deformation is occurring inside the object H, and to determine the fracture mechanism and the extent of that part. It was confirmed that useful information can be obtained in considering whether or not the product is deteriorating.
In the above embodiment, the small-angle scattering image and the strain distribution are displayed separately, but they may be displayed in an overlapping manner, or may be displayed in color or with arrows in addition to gradation.

(How to display acquired images)
In the above-mentioned photographing process A, three reconstructed images of Talbot photography, photographed images (photos (still images) and moving images), temperature distribution images, etc. are acquired for each tension step. The control unit 51 converts the small-angle scattering image and differential phase image of the subject H obtained by Talbot photography in the photographing process A into values (load value, stress value, tensile elongation amount, etc.), other images photographed or acquired together with the image (e.g., image taken by the camera 21, temperature distribution image, absorption image, etc.), and/or analysis results of the image (e.g., strain distribution numerical data, strain distribution images, identification results of elastic deformation or plastic deformation, etc.), etc.) and are displayed on the display unit 53. Thereby, the image acquired by the photographing process A can be displayed in an easy-to-see manner.

FIG. 19 shows a display example of an image acquired in the photographing process A. As shown in FIG. 19, for example, for each tensile step, all or part of the acquired images, including small-angle scattering images and differential phase images, are arranged on the screen, and the measurement date, measurement time, It is preferable to simultaneously display basic information regarding the test such as the sample name (subject name) and the value of the load applied to the subject H at each tension step.
The types and items of images displayed on the display section 53 may be settable according to the user's operation of the operation section 52 or the like. For example, the setting may be such that only the three reconstructed images obtained by Talbot imaging are displayed without displaying the image taken by the camera 21, or the setting may be set so that only the absorption image and the small-angle scattering image are displayed side by side.
When displaying a captured image, only a portion of the image may be enlarged and displayed. In that case, it is preferable that the control unit 51 automatically sets the enlarged display range so that the three reconstructed images have the same field of view. For example, when the user determines the field of view and magnification for the small-angle scattering image using the operation unit 52, it is preferable that the control unit 51 automatically sets the enlarged display range so that the same field of view and magnification are obtained for the absorption image and the differential phase image. . Note that the camera image, temperature distribution image, and strain analysis results may also be displayed at the same time, and the enlarged display range may be automatically set so that the same field of view is displayed. Further, it is preferable that the set field of view is also reflected when displaying images of different steps before and after.
Furthermore, it is preferable to control the display to return to the previous step or advance to the next step in response to operations such as clicking an arrow button on the screen, clicking the mouse, or moving a wheel. . Further, a series of images acquired by the photographing process A may be continuously displayed as a moving image/animation.

(contrast/brightness adjustment)
If the contrast and brightness of the image are adjusted individually for each pulling step, the brightness of the image will fluctuate for each pulling step when displayed, making it difficult to compare. Therefore, the control unit 51 automatically or in response to the user's operation of the operation unit 52 batches a series of images for each type of image (for example, each absorption image, each small-angle scattering image, and each differential phase image). It is preferable to adjust the contrast and brightness to be the same. This eliminates the sense of discomfort when a series of images acquired by photography is displayed as an animation or video. Note that although it is preferable to adjust the contrast and brightness of a series of images all at once, it is also possible to adjust only one of them.

(trend correction)
In the reconstructed images obtained by Talbot imaging, trends due to the equipment (overall patterns that are not inherent in the data, image unevenness, etc.) may occur, such as distorted grids, uneven grids, and fluctuations in ) may be superimposed, and image processing may be used to correct it. In particular, Talbot photography while performing a tensile test takes a long time, so it is possible that the trend may change due to subtle environmental changes such as temperature during the test. If the trend changes during a series of shootings, when you try to display and compare the series of images obtained from the shooting, the appearance of the images will change midway through, causing an unnatural feeling, or incorrect results may appear when comparing. There is a possibility that it will be stored away, which is not desirable.
In order to solve this problem, the control unit 51 may perform trend correction on the reconstructed image generated based on Talbot imaging. Trend correction can be performed using, for example, the method described in Japanese Patent No. 5831614. Since the trend occurs during Talbot imaging, trend correction may be performed individually for each image of each tension step rather than performing all the tension steps at once. If all steps are performed at once, it is also effective because the in-plane distribution of signal values possessed by the device itself can be corrected.

(save/read)
The control unit 51 stores a series of small-angle scattering images and differential phase images obtained by Talbot imaging in the imaging process A, respectively, with examination information such as the examination date (measurement date), examination time (measurement time), and subject name. A value representing the load applied to the subject H at the time of photographing the image (load value, stress value, amount of tensile elongation, etc.), other images photographed or acquired in conjunction with the image (for example, a photographed image of the camera 21, (temperature distribution image, absorption image, etc.), and/or analysis results of the image (e.g., numerical data of strain distribution, strain distribution image, identification result of elastic deformation or plastic deformation, etc.) (e.g., the same The test ID and step ID are assigned to the test ID and stored in the storage unit 55. This makes it possible to easily read out a group of images acquired at the same timing in the photographing process A.
Further, it is preferable that a series of images, moving images, and animations whose contrast and brightness have been adjusted are stored in the storage unit 55. Further, it is preferable that previously saved images can be read out again and settings such as the contrast/brightness, display field of view, display magnification, etc. can be changed.

(Estimating the degree of deterioration by constructing a database)
By combining Talbot imaging and tensile testing, it is possible to visualize the occurrence and development of minute microvoids and microcracks that cannot be seen with absorption images, as described above. Therefore, by analyzing the small-angle scattering image and differential phase image obtained by the above photographing process A to obtain information on microvoids and microcracks, and registering the analysis results in the database, a new subject H can be photographed. When this occurs, the degree of deterioration can be estimated.
For example, the control unit 51 performs Talbot imaging by performing the above-mentioned imaging process A until the subject H breaks, and the area where microcracks have occurred in the small-angle scattering image or differential phase image generated in each tensioning step. (for example, a region where the signal value is above a predetermined threshold), and calculate the signal strength, size (area, length), position (in-plane distribution), etc. of the extracted region to calculate the load and stress at each tensile step. It is stored in a database (a database constructed in the storage unit 55) as a reference in association with the value. The database may store not only the results of a single test (inspection results) but also the results of multiple tests, and the results of multiple tests may be integrated (for example, averaged) and stored in the database as a standard. You may.
Then, the control unit 51 subjects a new subject H (which may be a test piece made of the same material or a test piece created with the aim of improving characteristics by changing the material or the manufacturing conditions) to perform Talbot photography, and obtains a new object H. The areas where microcracks occur (areas where the signal value is greater than a predetermined threshold) are extracted from the small-angle scattering images and differential phase images, and the signal intensity, size (area, length), and area of the extracted areas are calculated. By acquiring internal distribution, load and stress values at the time of photographing, and comparing them with the values in the database, it is possible to check the degree of deterioration of a new test piece at that point, its strength compared to the standard, etc. without applying a load to the point of failure. can also be estimated. The degree of deterioration is determined by, for example, an area where microcracks occur in a small-angle scattering image or a differential phase image generated by Talbot imaging with a load applied to a new subject H (an area where the signal value is greater than or equal to a predetermined threshold). Compare the signal strength, size (area, length), position (in-plane distribution), etc. of This can be determined by calculating what percentage (percentage) of the load it corresponds to when the load is applied.
In addition, Talbot photography of the parts in use is performed, and the signal intensity, size, in-plane distribution, etc. of areas where microcracks occur (areas where the signal value is greater than a predetermined threshold) in the small-angle scattering image or differential phase image, etc. By comparing the information with a database, the degree of deterioration of the part may be estimated, and a judgment may be made as to whether the part should be replaced or not.

(Detection of changes in subject)
In the above embodiment, the work flow is explained in which the load is set on the tensile tester 23 and then the photograph is taken after waiting until the stress change due to the creep phenomenon stabilizes. However, as another method, the following (1) to (3) can be used. The shooting flow may be one of the following.
(1) Talbot imaging is performed at regular time intervals or at arbitrary timing, regardless of whether the stress value is stable. The images obtained by shooting are analyzed and the degree of blur, the amount of movement of the feature point position with respect to the previous image, and the degree of coincidence with the previous image (similarity, correlation) are determined. number) etc. Then, only those whose blur or amount of movement is less than a predetermined threshold or whose degree of coincidence is more than a predetermined threshold are extracted and stored in the storage unit 55 or used for analysis. On the other hand, other images that have a large amount of movement and include errors may be discarded or may be left, but they may be stored in the storage unit 55 with a flag indicating that they include errors, so that they can be used later. Make it possible to identify that errors are included.
(2) Regardless of whether the deformation of the subject H is stable or not, perform simple photography in which images are taken twice while moving the grid at fixed time intervals or at arbitrary timing, and reconstruct the resulting image. Analyze and calculate the degree of blur, the amount of movement of the feature point position from the previous image, the degree of coincidence with the previous image (similarity, correlation coefficient), etc. do. Then, when the blur or amount of movement is below a predetermined threshold or the degree of coincidence is above a predetermined threshold, Talbot imaging is performed. Note that in this case, it is necessary to obtain BG images in advance through two simple shootings. Alternatively, instead of simple imaging, simple absorption image imaging described in Reference Document 5 (Japanese Patent Laid-Open No. 2017-176399) may be performed. Simple absorption imaging is a method of generating an absorption image based on a moiré fringe image obtained by one radiography using one of the following methods using a Talbot interferometer or a Talbot-Lau interferometer.
- Radiography is performed by lowering the clarity of moiré fringes by inserting a scatterer into the irradiation field between the radiation source and the radiation detector.
- Imaging is performed with at least one of the plurality of gratings rotated around the radiation irradiation axis with respect to the position of the grating at the time of Talbot imaging.
- Imaging is performed with at least one of the plurality of gratings moved in the radiation irradiation axis direction with respect to the position of the grating at the time of Talbot imaging.
- Photographing is performed while moving at least one of the plurality of gratings in the slit period direction of the grating by 1/4 slit period or more.
(3) Take two images at a constant interval without moving the grid. If there is no variation, exactly the same image will be obtained. Therefore, the two images are compared, the amount of movement of the feature points, the degree of coincidence, etc. are calculated, and if the calculated amount of movement is less than a predetermined threshold or the degree of coincidence is greater than or equal to a predetermined threshold, Talbot Take pictures.

Note that in the case of simple imaging (2) and (3), the dose of X-rays may be lower than that in Talbot imaging. As a result, the heat load on the tube of the radiation source 11 can be reduced, the waiting time due to temperature rise can be reduced, the tube life can be extended, the amount of X-ray irradiation to the subject H can be reduced, and the deterioration and temperature of the subject H can be reduced. There are advantages such as being able to reduce the increase in

(Combination with DIC method)
A method called DIC (Digital Image Correlation) is a technology that visualizes the in-plane displacement distribution from the movement of markers when random markers are placed on the subject H and a tensile test is performed. known (for example, Japanese Patent Application Laid-Open No. 2006-32962
(See Publication No. 8).
Therefore, a plurality of markers may be placed (printed) on the subject H in advance using an inkjet printer or the like using materials that can be photographed using Talbot photography, and the subject H on which the markers are placed may be photographed using the photographing process A described above. . Then, the control unit 51 extracts the position of the marker in the reconstructed image obtained by Talbot imaging as a feature point using the DIC method, and calculates the strain distribution in the plane (xy plane) of the subject H based on the feature point. It may be calculated and visualized (displayed on the display unit 53 in a color according to the calculated value). In this way, even in cases/places where no feature points can be found with Talbot imaging, or even at a stage where microcracks have occurred within the plane and have not yet been detected using small-angle scattering images, It becomes possible to visualize the strain distribution. Furthermore, it becomes possible to calculate and visualize the in-plane stress distribution based on the calculated strain distribution.
Note that the ink used for printing the marker may be any ink that can be used for Talbot photography. For example, if the ink contains heavy metals, an absorption image can be taken. Furthermore, if the ink contains scattering fine particles or fibers with a diameter of 0.1 um to several hundred um, small-angle scattering images can be taken. Alternatively, by forming a water droplet shape with ink on the surface of the subject H, the contour can be photographed using a differential phase image. A combination of these may also be used.

(Regular BG (background) shooting)
Talbot imaging while making physical changes takes a certain amount of time, so during that time the condition of the equipment changes due to temperature fluctuations, which may cause a trend change in the reconstructed image and deteriorate the image. There is.
As mentioned earlier, trends on reconstructed images can be removed to some extent through image processing such as trend correction, but ideally it is possible to remove the effects of fluctuations during a series of measurements. It is preferable to perform Talbot photography (BG photography) with no subject H present.
For example, the inspection device 100 is configured to include a moving mechanism such as a moving stage or a robot arm for moving the tensile tester 23, and the control unit 51 moves the subject H and the tensile tester 23 from the imaging position at an arbitrary timing using the moving mechanism. Evacuate and take BG shots. The arbitrary timing may be, for example, immediately before setting the load and tension length in each tension step, or immediately before or after capturing a moire fringe image of the subject. Alternatively, the BG may be photographed for each of a plurality of tension steps. Then, the control unit 51 generates a reconstructed image using the subject moire fringe image photographed at each pulling step and the latest BG moire fringe image.
Note that BG photography does not need to be able to photograph the entire field of view; it is sufficient to be able to photograph only the portion where the subject H is located at the time of photography. Therefore, when moving the subject H and the tensile tester 23, it is not necessary to completely remove them from the field of view, but it is sufficient to move them to the extent that the area where the subject H is located at the time of photographing becomes an area where the subject H is not present. For example, in the case of the inspection apparatus 100, as shown in the absorption image of FIG. 20, an empty opening 24 exists around the subject H attached to the tensile tester 23. Therefore, there is no need to move the tensile tester 23 a long distance so that the entire tensile tester 23 becomes invisible from the field of view. All you have to do is return the subject H to the position and perform Talbot photography. This is preferable because the amount of movement can be reduced, the movement mechanism can be downsized, and positional deviations due to movement can be reduced.

[Second embodiment]
Next, a second embodiment of the present invention will be described.
FIG. 21 is a diagram schematically showing an inspection apparatus 200 in the second embodiment.
The inspection device 200 is a device that photographs the subject H while performing a heat load test in which heat is applied to the subject (subject H) and changes are observed.
As shown in FIG. 21, the main body 2 of the inspection device 200 includes a heating device 25 as a means for applying heat to the subject H, and a thermometer 26 for measuring the temperature of the subject H. The tensile tester 23 may not be provided. The control unit 51 of the controller 5 is connected to the heating device 25 and can control the heating device 25. Further, the control unit 51 is connected to the thermometer 26 and can obtain the temperature of the subject H. The storage unit 55 also stores a program for the control unit 51 to execute photographing process B, which will be described later. The rest of the configuration of the inspection device 200 is the same as that of the inspection device 100 described in the first embodiment, so the operation of the inspection device 200 will be described below with reference to the description.

FIG. 22 is a flowchart showing the imaging process B executed by the control unit 51 of the inspection device 200 and the program stored in the storage unit 55. This photographing process B is a process in which the heating temperature applied to the subject H by the heating device 25 is changed in stages, and the subject H is photographed at each stage (referred to as a heating step). In the photographing process B, the subject H is set on the subject stage 13, inspection conditions (for example, the set temperature and temperature increase rate of the heating device 25 for each photograph) are input through the operation unit 52, and photographing execution is instructed. Executed by In the following description, an example will be described in which the set temperature of the heating device 25 (the temperature at which the subject H is heated) is set as the inspection condition to heat the subject H. In addition, in this embodiment, before the start of the photographing process B, the second grid 15 is moved without setting the subject H on the subject stage 13, and the moire fringe image without the subject (BG (Back Ground) moire fringe image It is assumed that M pieces (for example, 4 pieces) are acquired and stored in the storage unit 55.

When the photographing process B is started, the control unit 51 uses the thermometer 26 to measure the temperature of the subject H before being heated by the heating device 25, and also photographs the subject H before being heated.
That is, the control unit 51 obtains the temperature of the subject H using the thermometer 26, causes the camera 21 to photograph the subject H, and obtains a photographed image. The photographed image is accompanied by an image number, photographing conditions, photographing date and time, etc. for identifying the image (step S21).
Next, the control unit 51 controls the radiation source 11, the moving mechanism 15a, the radiation detector 16, etc. to perform Talbot imaging, and obtains M moiré fringe images of the subject. In Talbot imaging, imaging is performed, for example, four times while moving the grating in the slit period direction. Then, reconstructed images (small-angle scattering image, differential phase image, absorption image) are generated based on the BG moire fringe image and the subject moire fringe image acquired in advance (step S22).

The generation of the reconstructed image is similar to that explained in step S2 of the first embodiment, so the explanation will be used here. The reconstructed image is accompanied by an image number for identifying the image, inspection conditions, photography conditions for Talbot photography, photography date and time, and the like.

Note that the order of steps S21 and S22 may be reversed or may be performed simultaneously. Further, it is preferable that the image taken by the camera 21 be taken at the same timing as Talbot photography as much as possible.
Further, the camera 21 may take still images or videos. When shooting a moving image, it is preferable that a signal is recorded at the same time so that it can be seen at which timing in the moving image Talbot photography was performed. This method is similar to that described in the first embodiment. Furthermore, instead of photographing with the camera 21, the absorption image generated based on Talbot photography in step S22 may be used as an image for comparison with the small-angle scattering image or the differential phase image. In this case, the camera photographing in step S21 can be omitted. Furthermore, in this embodiment, the camera 21 is preferably equipped with not only a general digital camera but also a thermography device, and it is preferable that the temperature distribution image of the subject H is photographed by the thermography device at the same time as the camera is photographed.

Next, the control unit 51 converts the photographed image acquired in step S21 (including the temperature distribution image if a temperature distribution image is acquired) and the reconstructed image acquired in step S22 to a value representing the temperature of the subject H at the time of photography. The information is stored in the storage unit 55 in association with each other (step S23).

Next, the control unit 51 determines whether the processing termination conditions are satisfied (step S24). For example, the conditions for terminating the process are as follows:
・Photography has been completed at all temperatures set as the inspection conditions of the heating device 25. ・The object H has sufficiently changed or changed in quality (deformation, melting, decomposition, etc.)
- Abnormal occurrence (occurrence of an unexpected situation. For example, smoke, fire, etc.)
- Possible causes include a predetermined number of repetitions of imaging being completed.
The determination as to whether an abnormality has occurred can be made, for example, by checking whether the user has performed a predetermined operation on the operation unit 52 indicating that an abnormality has been detected (for example, a button to be pressed when an abnormality is detected). The determination may be made based on whether the button is pressed or not, or the determination may be made by analyzing an image taken by the camera 21. Alternatively, a sensor may be provided to detect an abnormality such as smoke or ignition, and the determination may be made based on a detection signal from the sensor.

If it is determined that the processing termination conditions are not met (step S24; NO), the control unit 51 changes the set temperature of the heating device 25 based on the inspection conditions, and causes the heating device 25 to heat the subject H. The process is performed (step S25).

Next, the control unit 51 determines whether the temperature of the subject H obtained from the thermometer 26 has reached the set temperature value (step S26).
If it is determined that the temperature of the subject H obtained by the thermometer 26 does not reach the set temperature (step S26; NO), the control unit 51 waits until the temperature of the subject H reaches the set temperature.
If it is determined that the temperature of the subject H obtained by the thermometer 26 has reached the set temperature value (step S26; YES), the control unit 51 determines that the temperature of the tube of the radiation source 11 is lower than a predetermined standard. It is determined whether or not (step S27).
If it is determined that the temperature of the tube of the radiation source 11 is not lower than the predetermined standard (step S27; NO), the control unit 51 determines that the temperature of the tube of the radiation source 11 is lower than the predetermined standard. Wait until.

When determining that the temperature of the tube of the radiation source 11 is lower than a predetermined standard (step S27; YES), the control unit 51 determines whether the deformation of the subject H has stabilized (step S28).
Here, if Talbot photography is performed while the physical shape of the subject H is changing due to softening, dissolution, etc., the image will be blurred and the photography will fail, as in the first embodiment. Therefore, it is desirable to proceed with camera photography or Talbot photography after the deformation of the subject H has stabilized.
Whether or not the shape of the subject H has been stabilized can be determined by, for example, whether the user has performed a predetermined operation on the operation unit 52 indicating that the shape has been stabilized (for example, if the shape has been stabilized) The determination may be made based on whether a button is provided to be pressed and whether the button is pressed or not, or the camera 21 may take images at predetermined time intervals and compare the images with images taken immediately before. It may also be determined whether the shape of the subject H is stable. For example, it may be determined that the shape of the subject H has stabilized when the degree of similarity or correlation coefficient with an image photographed immediately before exceeds a predetermined threshold.

If it is determined that the deformation of the subject H is not stable (step S28; NO), the control unit 51 waits until the deformation of the subject H becomes stable.
If it is determined that the deformation of the subject H has stabilized (step S28; YES), the control unit 51 returns to step S21 and performs imaging.
The control unit 51 repeatedly executes the above-described steps until the end condition is satisfied, and ends the photographing process B when it is determined that the end condition is satisfied (step S24; YES).

(Example 4)
In order to verify the effectiveness of the second embodiment, an experiment of Example 4 was conducted.
In Example 4, in the inspection apparatus 200, Talbot imaging was performed while heating the object H, and from the obtained reconstructed image, it was evaluated how the inside of the object H changes due to heating. Specifically, the subject H was set on the subject stand 13 and the photographing process B of FIG. 22 was executed. Note that the camera photographing in step S21 of FIG. 22 was omitted, and an absorption image was used for comparison.
As the subject H, two types of waxes (wax W1: aqua wax, softening point 50°C; wax W2: Apiezon wax, softening point 80 to 90°C) were used. Heating was performed on the subject stage 13, and the state at that time was photographed using a Talbot. The temperature was read with a thermometer 26 placed near the subject H.

FIG. 23 shows an absorption image, a small-angle scattering image, and a differential phase image obtained by Talbot imaging in Example 4.
As shown in Fig. 23, wax W1 melts and its outline becomes unclear at (3) above the softening point of 50°C, and at the same time, in the small-angle scattering image and differential phase image, in the absorption image Air bubbles inside the invisible wax can be observed. In particular, it is clearly visible in the differential phase image. Furthermore, as the temperature is increased from (3) to (4) to (5) to (6), it can be observed that the bubbles gather in one place and disappear. Furthermore, when the temperature reaches 110° C. or higher (5), the wax W2 also begins to melt and the outline becomes unclear, which can be observed in the small-angle scattering image and the differential phase image. It was also found that no particularly significant change was observed when the heating was subsequently stopped and the temperature was lowered ((9), (10)).

As described above, by performing Talbot imaging while heating the object H, it is possible to observe the appearance of bubbles inside the object H, changes in the bubbles, and melting of the object H more clearly than with conventional absorption images. was confirmed. Such information can be utilized for various studies, such as considering soldering conditions for electronic components. Although the thermometer 26 placed near the subject H was used to measure the temperature, it is preferable to photograph and measure the temperature distribution with a thermography device because the temperature distribution inside the subject H can be seen.
As described above, according to the configuration and operation of the inspection device 200 of the second embodiment, without using a large-scale device, when a load is applied to the subject H, it is possible to obtain images that are not visible in conventional absorption X-ray images. This makes it possible to capture and observe changes inside a subject with a wider field of view in a shorter imaging time.

Note that the second embodiment also includes modifications of the first embodiment, such as (image acquisition display method), (detection of subject variation), (contrast/brightness adjustment), (trend correction), ( (save/read), (periodic BG photography), etc.

The first and second embodiments of the present invention and their modifications have been described above, but the description of the present embodiment described above is a preferred example of the present invention, and the present invention is not limited thereto.

For example, in the above embodiment, an inspection apparatus using a Talbot-Low interferometer of a type in which the second grating 15 is moved relative to the multi-slit 12 and the first grating 14 during imaging using the fringe scanning method was explained as an example. The present invention is applied to an inspection apparatus using a Talbot-Low interferometer that moves either the multi-slit 12, the first grating 14, or the second grating 15, or two gratings during imaging using the fringe scanning method. It's okay. Further, the present invention may be applied to an inspection apparatus using a Talbot interferometer in which either the first grating 14 or the second grating 15 is moved relative to the other grating. Further, the present invention may be applied to an inspection apparatus using a low interferometer in which either the multi-slit 12 or the first grating 14 is moved relative to another grating. Furthermore, the present invention may be applied to Talbot-Lau interferometers, Talbot interferometers, and Loau interferometers that use a Fourier transform method that does not require fringe scanning.

Furthermore, in the above embodiment, the case where a small angle scattering image, a differential phase image, and an absorption image are generated based on a moiré fringe image obtained by Talbot imaging has been described as an example. The present invention can be implemented in any device that generates images.

In addition, in the above embodiment, the case where Talbot photography is performed while subject H is subjected to a tensile test or a thermal load test is explained as an example, but changes in subject H may be observed by Talbot photography while subject H is subjected to a compression test or a bending test. Good too. Further, while performing a fatigue test or an endurance test in which a constant load is repeatedly applied to the subject H, Talbot photography may be performed to capture changes in the subject H every time the load is applied to the subject H a predetermined number of times. Further, a plurality of loads may be applied to the test piece in combination, for example, tension and heating may be applied simultaneously.

Further, for example, in the above description, an example is disclosed in which a hard disk, a semiconductor non-volatile memory, etc. are used as a computer-readable medium for the program according to the present invention, but the present invention is not limited to this example. As other computer-readable media, it is possible to apply a portable recording medium such as a CD-ROM. Further, a carrier wave (carrier wave) is also applied as a medium for providing data of the program according to the present invention via a communication line.

In addition, the detailed configuration and detailed operation of each device constituting the inspection device can be changed as appropriate without departing from the spirit of the invention.

100, 200 Inspection device 1, 2 Main body 11 Radiation source 12 Multi-slit 13 Subject stage 14 First grating 15 Second grating 15a Moving mechanism 16 Radiation detector 17 Support column 17a Buffer member 111 Focus 112 Additional filter/collimator 120 First Cover unit 130 Second cover unit 19 Base section 21 Camera 22 Mirror 23 Tensile tester 24 Opening section 25 Heating device 26 Thermometer 5 Controller 51 Control section 52 Operation section 53 Display section 54 Communication section 55 Storage section

Claims (16)

A radiation source, a plurality of gratings, and a radiation detector are provided side by side in the direction of the radiation irradiation axis, and the radiation source irradiates a plastic subject made of resin arranged in the direction of the radiation irradiation axis. Talbot imaging means for generating at least a differential phase image of the subject based on a moiré fringe image obtained by irradiating and imaging;
applying means for applying a load to the subject;
a control means that repeatedly performs control to generate a differential phase image by causing the Talbot photographing means to photograph the subject while applying a load to the subject by the applying means;
a detection means for detecting a change in the differential phase image based on the plurality of differential phase images of the subject generated by the Talbot imaging means;
Equipped with
The Talbot imaging means further generates a small-angle scattering image or an absorption image when generating the differential phase image based on the control of the control means,
A plurality of small-angle scattering images taken by the Talbot photographing means before applying a load to the test object by the applying means and after the test object is fractured by applying a load to the test object by the applying means, differential phase The positions of a plurality of feature points are extracted by analyzing an image or an absorption image, and the position of the subject is determined between the extracted plurality of feature points before applying a load to the subject and by applying a load to the subject. An inspection device comprising an identification means for identifying an elastically deformed portion and a plastically deformed portion inside the subject based on a comparison of distances after the specimen breaks. A radiation source, a plurality of gratings, and a radiation detector are provided side by side in the direction of the radiation irradiation axis, and the radiation source irradiates a plastic subject made of resin arranged in the direction of the radiation irradiation axis. Talbot imaging means for generating at least a differential phase image of the subject based on a moiré fringe image obtained by irradiating and imaging;
applying means for applying a load to the subject;
a control means that repeatedly performs control to generate a differential phase image by causing the Talbot photographing means to photograph the subject while applying a load to the subject by the applying means;
a detection means for detecting a change in the differential phase image based on the plurality of differential phase images of the subject generated by the Talbot imaging means;
Equipped with
The control means repeatedly performs control to generate a differential phase image by photographing the subject with the Talbot imaging means while applying a load to the subject with the applying means until the subject deteriorates,
From each of the plurality of differential phase images generated, a region where the signal value is equal to or higher than a predetermined threshold is extracted, and the signal intensity, size, and in-plane distribution of the extracted region are determined when the differential phase image is photographed. is stored in a database in association with a value representing the load applied to the subject by the imparting means, and a differential phase image obtained by photographing a new subject by the Talbot photographing means is stored in the database. An inspection apparatus comprising an estimating means for estimating the degree of deterioration of the new object based on accumulated information. 2. The control means repeatedly performs control to cause the Talbot photographing means to photograph the subject and generate a differential phase image each time the magnitude of the load applied to the subject by the applying means is changed. 2. The inspection device according to 2. 4. The control means controls the Talbot photographing means to perform the next photographing when a predetermined condition is satisfied after photographing by the Talbot photographing means. inspection equipment. The inspection apparatus according to claim 2, wherein the Talbot imaging means further generates a small-angle scattering image or an absorption image when generating the differential phase image based on the control of the control means. further comprising a photographing means for photographing the external appearance of the subject to obtain a photographed image of the subject;
The inspection apparatus according to any one of claims 1 to 5, wherein the control means further causes the photographing means to photograph the external appearance of the subject when the Talbot photographing means takes a photograph. further comprising temperature distribution image acquisition means for acquiring a temperature distribution image of the subject,
7. The inspection apparatus according to claim 1, wherein the control means further causes the temperature distribution image acquisition means to acquire a temperature distribution image of the subject when the Talbot photographing means takes an image. The Talbot imaging means further generates a small-angle scattering image or an absorption image when generating the differential phase image based on the control of the control means,
Analyzing a plurality of small-angle scattering images, differential phase images, or absorption images of the subject generated by the Talbot imaging means to extract the positions of a plurality of feature points, and changing the distance between the extracted plurality of feature points. The inspection apparatus according to any one of claims 1 to 7, further comprising strain distribution calculation means for calculating the strain distribution inside the subject by calculating the amount. A plurality of markers are arranged on the subject,
The strain distribution calculation means analyzes the plurality of small-angle scattering images, differential phase images, or absorption images, extracts the positions of the plurality of markers, and calculates the amount of change in distance between the plurality of extracted markers. The inspection device according to claim 8, wherein the strain distribution inside the subject is calculated by: 10. The method according to claim 8, further comprising highlighting means for generating a strain distribution image based on the strain distribution calculated by the strain distribution calculating means, and emphasizing and displaying parts of the strain distribution image on a display means where the distortion is large. inspection equipment. The Talbot imaging means further generates a small-angle scattering image or an absorption image when generating the differential phase image based on the control of the control means,
A plurality of small-angle scattering images taken by the Talbot photographing means before applying a load to the test object by the applying means and after the test object is fractured by applying a load to the test object by the applying means, differential phase 3. The inspection apparatus according to claim 2, further comprising identification means for analyzing an image or an absorption image and identifying whether the change inside the subject is due to elastic deformation or plastic deformation. A differential phase image of the subject acquired by the Talbot imaging means, a value representing the load applied to the subject at the time of photography, an image photographed or acquired together with the differential phase image, and/or the differential The inspection apparatus according to any one of claims 1 to 11, further comprising display control means for causing the display means to display the result in association with the analysis result of the phase image. A differential phase image of the subject acquired by the Talbot imaging means, a value representing the load applied to the subject at the time of photography, an image photographed or acquired together with the differential phase image, and/or the differential The inspection apparatus according to any one of claims 1 to 12, further comprising a storage control means for storing the analysis result of the phase image in the storage means in association with the analysis result. The inspection apparatus according to any one of claims 1 to 13, further comprising an adjustment unit that collectively adjusts the contrast and/or brightness of the image of the subject generated by the Talbot imaging unit for each type of image. . A radiation source, a plurality of gratings, and a radiation detector are provided side by side in the direction of the radiation irradiation axis, and the radiation source irradiates a plastic subject made of resin arranged in the direction of the radiation irradiation axis. Talbot imaging means for generating at least a differential phase image of the subject based on a moiré fringe image obtained by irradiating and imaging;
applying means for applying a load to the subject;
An image generation method in an inspection device comprising:
Repeatedly performing a process of generating a differential phase image and a small-angle scattering image or an absorption image by causing the Talbot imaging unit to image the subject while applying a load to the subject by the applying unit,
Detecting a change in the differential phase image based on the plurality of differential phase images of the subject generated by the Talbot imaging means,
A plurality of small-angle scattering images taken by the Talbot photographing means before applying a load to the test object by the applying means and after the test object is fractured by applying a load to the test object by the applying means, differential phase The positions of a plurality of feature points are extracted by analyzing an image or an absorption image, and the position of the subject is determined between the extracted plurality of feature points before applying a load to the subject and by applying a load to the subject. An image generation method that identifies an elastically deformed portion and a plastically deformed portion inside the subject based on a comparison of distances after fracture. A radiation source, a plurality of gratings, and a radiation detector are provided side by side in the direction of the radiation irradiation axis, and the radiation source irradiates a plastic subject made of resin arranged in the direction of the radiation irradiation axis. Talbot imaging means for generating at least a differential phase image of the subject based on a moiré fringe image obtained by irradiating and imaging;
applying means for applying a load to the subject;
An image generation method in an inspection device comprising:
Repeatedly performing a process of generating a differential phase image by causing the Talbot imaging unit to image the subject while applying a load to the subject by the applying unit;
Detecting a change in the differential phase image based on the plurality of differential phase images of the subject generated by the Talbot imaging means,
A plurality of differentials generated by repeatedly performing a process of photographing the subject with the Talbot imaging means and generating a differential phase image while applying a load to the subject with the applying means until the subject deteriorates. A region in which the signal value is equal to or greater than a predetermined threshold is extracted from each phase image, and the signal intensity, size, and in-plane distribution of the extracted region are determined by the imparting means when the differential phase image is photographed. Based on the differential phase image obtained by storing the data in a database in association with a value representing the load applied to the specimen and photographing a new specimen with the Talbot imaging means, and the information stored in the database. and estimating the degree of deterioration of the new object.

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