Image processing device, x-ray imaging device, and x-ray imaging system

Abstract

To provide an image processing device capable of presenting, to an operator, an image that allows positioning of a subject to be performed accurately while inhibiting a visual field shown in an optical image presented to the operator for positioning the subject from becoming narrow.SOLUTION: An image processing device 3 is an image processing device for generating an image for positioning a subject 90 in an X-ray imaging device 1, and includes: an image acquisition unit 2 including at least one optical camera 20 arranged in the vicinity of an X-ray irradiation unit 10 of the X-ray imaging device 1; and an image processing unit 30a for generating a focal point position image 41, which is an image of the same visual field as the visual field when imaging the subject 90 from the position of a focal point 60 of the X-ray irradiation unit 10, and an image in which a region 63a of an X-ray irradiation range 63 which is a range irradiated with an X-ray by the X-ray irradiation unit 10 and a region 64 outside the X-ray irradiation range 63 are shown on the basis of an optical image 40 captured by the optical camera 20.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an image processing device, an X-ray imaging device, and an X-ray imaging system, and more particularly to an image processing device, an X-ray imaging device, and an X-ray imaging system that present an image to an operator when positioning a subject in the X-ray imaging device. [Background technology]

[0002] 2. Description of the Related Art Conventionally, there is known an image processing device that presents an image to an operator when positioning a subject in an X-ray imaging device (see, for example, Patent Document 1).

[0003] The above-mentioned Patent Document 1 discloses an X-ray imaging device including an X-ray tube capable of irradiating X-rays, an aperture device capable of limiting the irradiation range of X-rays from the X-ray tube, an X-ray film device for detecting X-rays and generating an X-ray image, and a TV camera. The X-ray imaging device disclosed in the above-mentioned Patent Document 1 is configured to display an image captured by the TV camera on a monitor in order to align the subject with the X-ray tube. In addition, in the configuration disclosed in the above-mentioned Patent Document 1, the TV camera is disposed in a position conjugate with the focal position of the X-rays in the aperture device. As a result, the TV camera disclosed in the above-mentioned Patent Document 1 is configured to be able to capture a surface image of the subject in a shooting range corresponding to the aperture device. Note that the position conjugate with the focal position of the X-rays is a position optically equivalent to the focal position of the X-rays, and is a position at which an image of the same field of view can be captured even when the positions of the two are interchanged. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-217973 Summary of the Invention [Problem to be solved by the invention]

[0005] Here, as disclosed in the above Patent Document 1, by arranging the optical camera in a position conjugate with the X-ray focus in the aperture device, the optical image and the X-ray image become images of the same field of view. Therefore, it is possible to accurately position the subject using the optical image. However, in the configuration disclosed in the above Patent Document 1, since the optical camera is arranged in the aperture device, the photographing range of the optical camera is limited to the irradiation range of the X-ray. Therefore, there is a disadvantage that the field of view reflected in the optical image photographed by the optical camera is narrowed. When the field of view reflected in the optical image is narrowed, there is a problem that it becomes difficult to position the subject while checking the optical image displayed on the display unit.

[0006] The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to provide an image processing device, an X-ray imaging device, and an X-ray imaging system that can present an image to an operator that enables accurate positioning of the subject, while suppressing narrowing of the field of view in the optical image presented to the operator for positioning the subject. [Means for solving the problem]

[0007] An image processing device according to a first aspect of the present invention is an image processing device that generates an image for positioning a subject in an X-ray imaging device, and includes an image acquisition unit including at least one optical camera arranged near an X-ray irradiation unit of the X-ray imaging device, and an image processing unit that generates a focal position image based on an optical image captured by the optical camera, which is an image of the same field of view as when the subject is imaged from the position of the focus of the X-ray irradiation unit, and which is an image showing an area of ​​the X-ray irradiation range, which is the range where X-rays are irradiated by the X-ray irradiation unit, and an area outside the X-ray irradiation range. Note that the vicinity of the X-ray irradiation unit means the vicinity of the position of the X-ray irradiation unit.

[0008] An X-ray imaging device in a second aspect of the present invention includes an X-ray irradiation unit that irradiates X-rays, an X-ray detection unit that detects the X-rays irradiated by the X-ray irradiation unit, an image acquisition unit including at least one optical camera arranged in the vicinity of the X-ray irradiation unit, and an image processing unit that generates a focal position image based on the optical image captured by the optical camera, which is an image of the same field of view as when the subject is photographed from the position of the focal point of the X-ray irradiation unit and which includes an area of ​​the X-ray irradiation range, which is the range where X-rays are irradiated by the X-ray irradiation unit, and an area outside the X-ray irradiation range.

[0009] An X-ray imaging system in a third aspect of the present invention includes an X-ray irradiation unit that irradiates X-rays, an X-ray detection unit that detects the X-rays irradiated by the X-ray irradiation unit, an image acquisition unit including at least one optical camera arranged in the vicinity of the X-ray irradiation unit, and an image processing unit that generates a focal position image based on the optical image captured by the optical camera, which is an image of the same field of view as when the subject is photographed from the position of the focal point of the X-ray irradiation unit and which includes an area of ​​the X-ray irradiation range, which is the range where X-rays are irradiated by the X-ray irradiation unit, and an area outside the X-ray irradiation range. Effect of the Invention

[0010] The image processing device according to the first aspect, the X-ray imaging device according to the second aspect, and the X-ray imaging system according to the third aspect of the present invention are provided with an image processing unit that generates a focal position image, which is an image of the same field of view as when the subject is imaged from the position of the focus of the X-ray irradiation unit, and which is an image showing the area of ​​the X-ray irradiation range, which is the range where X-rays are irradiated by the X-ray irradiation unit, and the area outside the X-ray irradiation range. As a result, since the focal position image has the same field of view as when the subject is imaged from the position of the focus of the X-ray irradiation unit, the focal position image and the X-ray image are images of the same field of view. In addition, since both the area of ​​the X-ray irradiation range and the area outside the X-ray irradiation range are shown in the focal position image, it is possible to prevent the field of view shown in the optical image presented to the operator for positioning the subject from narrowing. As a result, it is possible to present to the operator an image (focal position image) that allows accurate positioning of the subject while preventing the field of view of the optical image presented to the operator for positioning the subject from narrowing. [Brief description of the drawings]

[0011] [Figure 1] 1 is a block diagram showing the configuration of an X-ray imaging system including an image processing device according to a first embodiment. [Diagram 2] 1 is a schematic diagram showing the configuration of an X-ray imaging device provided in an X-ray imaging system according to a first embodiment. [Diagram 3] FIG. 2 is a schematic diagram for explaining the arrangement of optical cameras provided in the X-ray imaging apparatus according to the first embodiment. [Figure 4] 3A and 3B are schematic diagrams for explaining the field of view of an optical image captured by a first optical camera according to the first embodiment. [Diagram 5] 10 is a schematic diagram for explaining the field of view of an optical image taken by an optical camera according to a comparative example from a direction along the irradiation axis of X-rays outside a collimator. FIG. [Figure 6] 10 is a schematic diagram for explaining the field of view of an optical image captured by an optical camera according to a comparative example from a position conjugate with the focal point of X-rays inside a collimator. FIG. [Figure 7]1A to 1C are schematic diagrams illustrating a configuration in which an image processing unit according to a first embodiment generates a focus position image. [Figure 8] 4 is a schematic diagram for explaining a configuration for displaying a focal point image in a display unit included in the X-ray imaging system according to the first embodiment. FIG. [Figure 9] 1A to 1C are schematic diagrams illustrating a configuration in which an image processing unit according to a first embodiment generates a body movement amount display image. [Figure 10] 5 is a flowchart for explaining a process for generating a focus position image by an image processing unit according to the first embodiment. [Figure 11] 5 is a flowchart for explaining a process of switching an image to be output by an image output control unit according to the first embodiment. [Figure 12] 5 is a flowchart for explaining a process in which an image processing unit according to the first embodiment generates a body movement amount display image and displays it on a display unit. [Figure 13] FIG. 11 is a block diagram showing the configuration of an X-ray imaging system including an image processing device according to a second embodiment. [Figure 14] FIG. 11 is a schematic diagram for explaining the arrangement of optical cameras provided in the X-ray imaging apparatus according to the second embodiment. [Figure 15] 13 is a schematic diagram for explaining a focus position image generated by an image processing unit according to the second embodiment. FIG. [Figure 16] 10 is a flowchart for explaining a process for generating a focus position image by an image processing unit according to the second embodiment. [Figure 17] FIG. 11 is a block diagram showing the configuration of an X-ray imaging system including an image processing device according to a third embodiment. [Figure 18] 13 is a flowchart for explaining a process for generating a focus position image by an image processing unit according to the third embodiment. [Figure 19] FIG. 13 is a block diagram showing the configuration of an X-ray imaging system including an image processing device according to a modified example of the first embodiment. [Figure 20]11 is a schematic diagram for explaining a configuration in which an image processing unit according to a comparative example generates a focus position image. FIG. [Figure 21] FIG. 11 is a schematic diagram for explaining a parallax used when an image processing unit according to a modified example of the first embodiment generates a focus position image. [Figure 22] 10 is a flowchart for explaining a process for generating a focus position image by an image processing unit according to a modified example of the first embodiment. [Figure 23] FIG. 13 is a block diagram showing the configuration of an X-ray imaging system including an image processing device according to a first modified example. [Figure 24] FIG. 11 is a block diagram showing the configuration of an X-ray imaging apparatus including an image processing unit according to a second modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0013] [First embodiment] First, the configurations of an X-ray imaging device 1, an image processing device 3, and an X-ray imaging system 100 according to the first embodiment will be described with reference to Fig. 1 to Fig. 9. As shown in Fig. 1, the X-ray imaging system 100 includes an X-ray imaging device 1, an image acquisition unit 2, and an image processing device 3. The X-ray imaging device 1, the image acquisition unit 2, and the image processing device 3 are different devices. The X-ray imaging system 100 also includes a tabletop 4, a tabletop movement mechanism 5, and an input reception unit 6.

[0014] The X-ray imaging device 1 has an X-ray irradiation unit 10 and an X-ray detector 11. The X-ray imaging device 1 also has an apparatus control unit 12, a display unit 13, an irradiation unit moving mechanism 14, and a detector moving mechanism 15. The X-ray imaging device 1 is a device that generates an X-ray image (not shown) of a subject 90 (see FIG. 2) by using X-rays irradiated from the X-ray irradiation unit 10.

[0015] The X-ray irradiation unit 10 is configured to irradiate the subject 90 with X-rays. The X-ray irradiation unit 10 also includes an X-ray source 10a that generates X-rays for irradiating the subject 90 with X-rays, a collimator 10b that adjusts an irradiation range 63 (see FIG. 7(A)) of the X-rays, and a projection lamp 10c.

[0016] The X-ray source 10a includes, for example, an X-ray generating device such as an X-ray tube. The collimator 10b is provided to adjust an irradiation range 63 of the X-rays irradiated from the X-ray irradiator 10. The collimator 10b is also provided to adjust the shape of the irradiation range 63 of the X-rays irradiated from the X-ray irradiator 10.

[0017] The collimator 10b has a flat plate shape with an opening at the center. The collimator 10b is formed by forming an opening in a flat plate made of, for example, a lead material. The collimator 10b adjusts the size and shape of the opening under the control of the device control unit 12, thereby adjusting the X-ray irradiation range 63.

[0018] The projection lamp 10c is configured to project visible light in a range similar to the X-ray irradiation range 63 adjusted by the collimator 10b. The projection lamp 10c is disposed, for example, inside a housing 10d (see FIG. 3) of the collimator 10b at a position conjugate with the X-ray focal point 60 (see FIG. 3). The projection lamp 10c includes, for example, a halogen lamp or an LED (Light Emitting Diode) lamp.

[0019] The X-ray detector 11 is configured to detect X-rays irradiated by the X-ray irradiation unit 10. The X-ray detector 11 is, for example, a FPD (Flat Panel Detector), and detects X-rays that have passed through the subject 90. The X-ray detector 11 is also portable, and configured to be capable of being held by the subject 90 to perform imaging.

[0020] The device control unit 12 is configured to control the entire X-ray imaging device 1. Specifically, the device control unit 12 is configured to control X-ray irradiation by the X-ray irradiation unit 10 (X-ray source 10a), such as starting and stopping X-ray irradiation, control changing the X-ray irradiation range 63 by the X-ray irradiation unit 10 (collimator 10b), control detection by the X-ray detector 11, control of movement of the X-ray irradiation unit 10 by the irradiation unit moving mechanism 14, control of movement of the X-ray detector 11 by the detector moving mechanism 15, and the like.

[0021] The device control unit 12 is configured with a processor such as a CPU (Central Processing Unit), an FPGA (field-programmable gate array), or a circuit, and a memory such as a ROM (Read Only Memory) and a RAM (Random Access Memory). The device control unit 12 is configured to receive detection signals from an encoder and a potentiometer included in the irradiation unit moving mechanism 14. The device control unit 12 is configured to control a motor and an electromagnetic brake included in the irradiation unit moving mechanism 14. The device control unit 12 is configured to control a motor and an electromagnetic brake included in the detector moving mechanism 15.

[0022] The display unit 13 is configured to display an optical image 40 captured by an optical camera 20 (described later), etc. The display unit 13 is, for example, a display device such as a liquid crystal monitor or an organic EL (Electro Luminescence) monitor.

[0023] The irradiation unit moving mechanism 14 is configured so that an operator can move the X-ray irradiation unit 10. The detailed configuration of the irradiation unit moving mechanism 14 will be described later.

[0024] The detector moving mechanism 15 movably holds the X-ray detector 11. Therefore, by moving the X-ray detector 11 with the detector moving mechanism 15, the X-ray detector 11 can be disposed at a position according to the part of the subject 90 to be imaged.

[0025] The image acquisition unit 2 includes at least one optical camera 20 disposed near the X-ray irradiation unit 10 of the X-ray imaging device 1. In the first embodiment, the optical camera 20 includes a first optical camera 20a and a second optical camera 20b disposed at different positions. The image acquisition unit 2 is configured to acquire a first optical image 40a, which is an optical image 40 captured by the first optical camera 20a, and a second optical image 40b, which is an optical image 40 captured by the second optical camera 20b. The first optical camera 20a and the second optical camera 20b are imaging devices including an image sensor capable of receiving visible light, such as a CMOS (Complementary Metal Oxide Semiconductor) sensor or a CCD (Charge Coupled Device) sensor. The arrangement of the first optical camera 20a and the second optical camera 20b will be described later.

[0026] The image processing device 3 includes a control unit 30 and a storage unit 31. The image processing device 3 according to the first embodiment is an image processing device that generates an image for positioning a subject 90 in the X-ray imaging device 1.

[0027] The control unit 30 is configured to control the image processing device 3. The control unit 30 is configured with a processor such as a CPU, FPGA, or circuitry, and memories such as a ROM and RAM. The control unit 30 also includes an image processing unit 30a and an image output control unit 30b. The image processing unit 30a and the image output control unit 30b are configured in software as functional blocks realized by the control unit 30 executing a program. The image processing unit 30a and the image output control unit 30b may be configured in hardware by providing a dedicated processor (processing circuit).

[0028] The image processing unit 30a is configured to generate a focus position image 41, which will be described later. In the first embodiment, the image processing unit 30a is configured to generate a body movement amount display image 42, which will be described later. Details of the configuration in which the image processing unit 30a generates the focus position image 41 and the body movement amount display image 42 will be described later.

[0029] The image output control unit 30b is configured to perform control to output the focus position image 41 to the display unit 13. Details of the configuration in which the image output control unit 30b outputs the focus position image 41 to the display unit 13 will be described later.

[0030] The storage unit 31 is configured to store an optical image 40, a focal position image 41, and a body movement amount display image 42. The storage unit 31 is also configured to store arrangement information 50 of the first optical camera 20a and arrangement information 51 of the second optical camera 20b. The storage unit 31 is also configured to store a trained model 52 used when the image processing unit 30a generates the focal position image 41. The storage unit 31 also stores various programs (not shown) executed by the control unit 30. The storage unit 31 includes a non-volatile storage device such as a hard disk drive (HDD) or a solid state drive (SSD).

[0031] The arrangement information 50 of the first optical camera 20a is position information when the first optical camera 20a is arranged in the X-ray irradiation unit 10. The arrangement information 51 of the second optical camera 20b is position information when the second optical camera 20b is arranged in the X-ray irradiation unit 10. Details of the arrangement information 50 of the first optical camera 20a and the arrangement information 51 of the second optical camera 20b will be described later.

[0032] The trained model 52 is a trained model generated by learning to generate a focal position image 41 based on an optical image 40. Specifically, the trained model 52 is a trained model generated by learning to generate an image of the same field of view as when the subject 90 is photographed from the position of the X-ray focal point 60 from a plurality of optical images 40 photographed from mutually different oblique directions.

[0033] The top board 4 is configured so that a subject 90 can be placed thereon. The configuration of the top board 4 will be described in detail later.

[0034] The top board moving mechanism 5 is configured to move the top board 4 and change the position of the subject 90 with respect to the X-ray detector 11. The configuration of the top board moving mechanism 5 will be described in detail later.

[0035] The input reception unit 6 is configured to receive an operation input from an operator. The input reception unit 6 is, for example, a touch pad. In the first embodiment, the input reception unit 6 is configured as a touch panel integrally formed with the display unit 13.

[0036] (Configuration of X-ray device and tabletop movement mechanism) As shown in FIG. 2, in the X-ray imaging device 1, the X-ray irradiator 10 is supported by the irradiator moving mechanism 14 so as to be suspended from the ceiling. The X-ray irradiator 10 is supported by the irradiator moving mechanism 14 so as to be movable within the imaging room. The irradiator moving mechanism 14 is provided with a motor and an electromagnetic brake (not shown) corresponding to each of the X, Y, and Z directions. The X-ray irradiator 10 is configured to be movable in each of the X, Y, and Z directions by an operator. In the example shown in FIG. 2, the up-down direction is the Z direction, the up direction is the Z1 direction, and the down direction is the Z2 direction. One side of two directions mutually perpendicular to the Z direction is the X direction, and the other side is the Y direction. One side of the X direction is the X1 direction, and the other side is the X2 direction. One side of the Y direction is the Y1 direction, and the other side is the Y2 direction.

[0037] The X-ray irradiator 10 is configured to be rotatable around the Z-axis while being held by the irradiator moving mechanism 14. The X-ray irradiator 10 is configured to be rotatable around the Y-axis while being held by the irradiator moving mechanism 14. Therefore, the X-ray irradiator 10 is configured to be able to change the irradiation direction and angle of the X-rays. The irradiator moving mechanism 14 is provided with a motor and an electromagnetic brake (not shown) corresponding to each of the two rotatable axes (Y-axis and Z-axis) of the X-ray irradiator 10. The irradiator moving mechanism 14 is provided with an encoder (not shown) and a potentiometer (not shown) corresponding to each of the two rotatable axes (Y-axis and Z-axis) of the X-ray irradiator 10. The irradiator moving mechanism 14 according to the first embodiment moves the X-ray irradiator 10 in a direction according to the direction of the operating force input by the operator when the operator moves the X-ray irradiator 10.

[0038] As shown in Fig. 2, the first optical camera 20a and the second optical camera 20b are disposed near the collimator 10b. In the example shown in Fig. 2, the first optical camera 20a and the second optical camera 20b are disposed at equal positions in the X direction and the Z direction, and at different positions in the Y direction. In the example shown in Fig. 2, the first optical camera 20a is hatched, but this is not to show a cross section of the first optical camera 20a, but to improve the visibility of the first optical camera 20a in Fig. 2.

[0039] The top board 4 has a support surface 4a on which the subject 90 is placed. The top board moving mechanism 5 includes a motor and an electromagnetic brake (not shown) corresponding to each of the X, Y, and Z directions. The top board 4 is configured to be movable in each of the X, Y, and Z directions by the top board moving mechanism 5.

[0040] The detector moving mechanism 15 also includes a detector holding part 15a capable of holding the X-ray detector 11. The detector moving mechanism 15 is configured to be able to move the X-ray detector 11 held by the detector holding part 15a in the Z direction by moving the detector holding part 15a in the Z direction. The X-ray imaging device 1 according to the first embodiment is capable of performing imaging in a state where the subject 90 holds the X-ray detector 11, imaging in a state where the X-ray detector 11 is placed on the placement surface 4a of the top board 4, and imaging in a state where the X-ray detector 11 is placed on the detector holding part 15a. That is, the X-ray imaging device 1 according to the first embodiment is capable of performing imaging in a state where the subject 90 is seated on the top board 4 (sitting position), imaging in a state where the subject 90 is lying on the top board 4 (supine position), and imaging in a state where the subject 90 is standing (standing position).

[0041] (Optical camera placement) 3 is a schematic diagram of the collimator 10b viewed from the Z1 direction. As shown in FIG. 3, at least one optical camera 20 is provided outside the housing 10d of the collimator 10b included in the X-ray irradiation unit 10. In the first embodiment, the first optical camera 20a and the second optical camera 20b are disposed in a position near the X-ray irradiation unit 10. Specifically, the first optical camera 20a and the second optical camera 20b are provided on one side and the other side of the outside of the housing 10d of the collimator 10b with the focal point 60 of the X-ray irradiation unit 10 as a reference. More specifically, the first optical camera 20a and the second optical camera 20b are provided outside the housing 10d of the collimator 10b so as to be symmetrical with respect to the focal point 60 of the X-ray irradiation unit 10 as a reference. In this embodiment, the first optical camera 20a is provided on the Y1 direction side with respect to the X-ray focal point 60, and the second optical camera 20b is provided on the Y2 direction side with respect to the X-ray focal point 60. In other words, the first optical camera 20a and the second optical camera 20b are disposed at positions that are linearly symmetric with respect to the X-ray irradiation axis 61.

[0042] That is, the first optical camera 20a and the second optical camera 20b are positioned symmetrically with respect to the position of the focal point 60 of the X-ray irradiation unit 10, and are configured to capture the first optical image 40a (see Figure 1) and the second optical image 40b (see Figure 1).

[0043] The first optical camera 20a photographs the subject 90 (see FIG. 2) from an oblique direction to the irradiation axis 61 along the direction indicated by the arrow 80a. The second optical camera 20b photographs the subject 90 from an oblique direction to the irradiation axis 61 along the direction indicated by the arrow 80b.

[0044] The storage unit 31 (see FIG. 1) stores position information of the first optical camera 20a in the housing 10d of the collimator 10b and the like as arrangement information 50 (see FIG. 1) of the first optical camera 20a. For example, the storage unit 31 stores the distance in the X direction and the distance in the Y direction from the focal point 60 of the X-rays to the first optical camera 20a, and the angle θ1 of the arrow 80a with respect to the irradiation axis 61 as the arrangement information 50 of the first optical camera 20a.

[0045] The memory unit 31 also stores the distance in the X direction and the distance in the Y direction from the X-ray focal point 60 to the second optical camera 20b, and the angle θ2 of the arrow 80b with respect to the irradiation axis 61 as position information 51 of the second optical camera 20b.

[0046] (Difference in the field of view of optical images due to the placement of optical cameras) Next, a difference in the field of view of the optical image 40 (see FIG. 1) due to a difference in the arrangement of the optical camera 20 (see FIG. 1) will be described with reference to Figures 4 and 5. Note that in both Figures 4 and 5, the optical image 40 is taken with the knee 90a of the subject 90 positioned so as to be located at the center of the X-ray detector 11.

[0047] The first optical image 40a shown in FIG. 4 is an optical image 40 captured by the first optical camera 20a (see FIG. 3). The first optical image 40a shows the knee 90a, which is the imaging site of the subject 90, and the X-ray detector 11 held by the subject 90. The first optical image 40a also shows a crosshair 62 for indicating to the operator the irradiation range 63 (see FIG. 7(A)) of the X-rays irradiated from the X-ray irradiation unit 10 (see FIG. 1). The crosshair 62 is irradiated onto the detection surface of the X-ray detector 11 by a projection lamp 10c (see FIG. 1) arranged at a position conjugate with the X-ray focal point 60 (see FIG. 3) inside the collimator 10b (see FIG. 3). Therefore, the crosshair 62 serves as a guide for positioning the imaging site (knee 90a) of the subject 90.

[0048] The third optical image 40c according to the comparative example shown in Fig. 5 is an image obtained when the optical camera 20 is placed at a position where it can capture an image in a direction along the X-ray irradiation axis 61 (see Fig. 3) outside the collimator 10b (see Fig. 3). The knee 90a of the subject 90, the X-ray detector 11, and the crosshairs 62 are also captured in the third optical image 40c.

[0049] When comparing the first optical image 40a and the third optical image 40c, the fields of view of the images are different due to differences in the arrangement of the optical camera 20. Specifically, in the first optical image 40a shown in Fig. 4, the knee 90a of the subject 90 is photographed from an oblique direction, so that the knee 90a of the subject 90 is photographed at a position offset from the center of the X-ray detector 11. In addition, the center of the crosshairs 62 is also photographed at a position offset from the center of the X-ray detector 11.

[0050] On the other hand, in the third optical image 40c shown in FIG. 5, the knee 90a of the subject 90 is photographed along the X-ray irradiation axis 61, so that the knee 90a of the subject 90 is located at the center of the X-ray detector 11. The center of the crosshairs 62 is also located at the center of the X-ray detector 11. In addition, in the third optical image 40c in FIG. 5, a part of the crosshairs 62 is illustrated by a broken line. This is because the light irradiated from the lamp is blocked by the optical camera 20 arranged to photograph the third optical image 40c. That is, the operator cannot see the crosshairs 62 illustrated by the broken line in the third optical image 40c. In addition, since the X-rays irradiated from the X-ray source 10a (see FIG. 1) are also blocked by the optical camera 20, the optical camera 20 cannot be arranged at a position outside the housing 10d of the collimator 10b where it can photograph in a direction along the X-ray irradiation axis 61.

[0051] Therefore, in order to allow the operator to visually recognize the crosshairs 62 in the third optical image 40c shown in FIG. 5, it is conceivable to place the optical camera 20 inside the collimator 10b (see FIG. 3) at a position conjugate with the X-ray focal point 60 (see FIG. 3). However, when the optical camera 20 is placed inside the collimator 10b, the field of view captured in the optical image 40 is limited to the X-ray irradiation range 63 (see FIG. 7(A)) as in the fourth optical image 40d shown in FIG. 7. Therefore, the fourth optical image 40d has a narrow field of view in which only a part of the knee 90a of the subject 90 and a part of the X-ray detector 11 are captured, making it difficult for the operator to position the subject 90 while checking.

[0052] (Generation of focal position image) Therefore, in the first embodiment, the image processing unit 30a (see FIG. 1) is configured to generate a focal position image 41 (see FIG. 7(C)) based on an optical image 40 captured by an optical camera 20 provided outside a housing 10d (see FIG. 3) of the collimator 10b. Specifically, the image processing unit 30a is configured to generate the focal position image 41 based on a first optical image 40a shown in FIG. 7(A) and a second optical image 40b shown in FIG. 7(B).

[0053] The image shown in Fig. 7(A) is a first optical image 40a captured by the first optical camera 20a (see Fig. 3). The first optical image 40a captures a head 90b of a subject 90 (see Fig. 2) and a detector holder 15a that holds an X-ray detector 11 (see Fig. 2). The first optical image 40a also captures an area 63a of an X-ray irradiation range 63 irradiated from an X-ray irradiation unit 10 (see Fig. 2) and an area 64 outside the X-ray irradiation range 63. Since the first optical camera 20a is provided on the Y1 direction side with respect to the X-ray irradiation axis 61 (see Fig. 3), the first optical image 40a captures a head 90b of the subject 90 viewed from the Y1 direction side (left side).

[0054] The image shown in Fig. 7(B) is a second optical image 40b captured by the second optical camera 20b (see Fig. 3). The second optical image 40b also captures a head 90b of the subject 90 (see Fig. 2) and a detector holder 15a. The second optical image 40b also captures an area 63a of an X-ray irradiation range 63 irradiated from the X-ray irradiation unit 10 (see Fig. 2) and an area 64 outside the X-ray irradiation range 63. Since the second optical camera 20b is provided on the Y2 direction side with respect to the X-ray irradiation axis 61 (see Fig. 3), the second optical image 40b captures the head 90b of the subject 90 (see Fig. 2) viewed from the Y2 direction side (right side).

[0055] The image shown in Fig. 7(C) is a focal position image 41 generated by the image processing unit 30a (see Fig. 1). The focal position image 41 is an image of the same field of view as when an image of a subject 90 (see Fig. 2) is captured from the position of the focal point 60 (see Fig. 3) of the X-ray irradiation unit 10 based on an optical image 40 (see Fig. 1) captured by the optical camera 20 (see Fig. 1), and is an image that captures an area 63a of an X-ray irradiation range 63, which is a range where X-rays are irradiated by the X-ray irradiation unit 10, and an area 64 outside the X-ray irradiation range 63.

[0056] In the first optical image 40a, the head 90b of the subject 90 is shown in a position shifted to the left side of the region 63a of the X-ray irradiation range 63. In the second optical image 40b, the head 90b of the subject 90 is shown in a position shifted to the right side of the region 63a of the X-ray irradiation range 63. On the other hand, in the focal position image 41, the head 90b of the subject 90 is shown in the center part of the region 63a of the X-ray irradiation range 63.

[0057] That is, in the first embodiment, the image processing unit 30a is configured to generate a focal position image 41 based on a first optical image 40a and a second optical image 40b taken from an oblique direction on one side and an oblique direction on the other side, based on the position of the focal point 60 of the X-ray irradiation unit 10.

[0058] (Method of generating focal position image) In the first embodiment, the image processing unit 30a is configured to generate a focal position image 41 by combining the first optical image 40a and the second optical image 40b based on the arrangement information 50 (see FIG. 1) of the first optical camera 20a and the arrangement information 51 (see FIG. 1) of the second optical camera 20b. For example, the image processing unit 30a weights each pixel included in the first optical image 40a and the second optical image 40b according to the distance from the position based on the X-ray irradiation axis 61 (see FIG. 3), and then performs projective transformation on the first optical image 40a and the second optical image 40b, and generates the focal position image 41 by combining the first optical image 40a and the second optical image 40b after the projective transformation. The image processing unit 30a may transform the first optical image 40a and the second optical image 40b by affine transformation. The image processor 30a may be configured to generate the focus position image 41 by averaging the first optical image 40a and the second optical image 40b that have been transformed by projective transformation or the like.

[0059] In the first embodiment, the image processing unit 30a may be configured to generate the focus position image 41 based on the trained model 52 (see FIG. 1), the first optical image 40a, and the second optical image 40b. That is, the image processing unit 30a may be configured to generate the focus position image 41 by inputting the first optical image 40a and the second optical image 40b to the trained model 52.

[0060] In the first embodiment, the image processing unit 30a generates one frame of a focus position image 41 by combining the first optical image 40a and the second optical image 40b after performing the weighted projective transformation described above, or by a method using the trained model 52, each time one frame of the first optical image 40a and the second optical image 40b are acquired. The image processing unit 30a generates the focus position image 41 for each frame at a predetermined frame rate, thereby generating the focus position image 41 as a moving image.

[0061] (Display of focal position image) In the first embodiment, as shown in FIG. 8, the image output control unit 30b (see FIG. 1) is configured to output a focal position image 41 to the display unit 13 provided in the X-ray irradiation unit 10. The display unit 13 is configured to display the focal position image 41 output from the image output control unit 30b. Note that in the first embodiment, the image output control unit 30b outputs the focal position image 41 to the display unit 13 as a moving image. Therefore, the display unit 13 displays the focal position image 41, which is a moving image, in real time.

[0062] In the first embodiment, the image output control unit 30b is configured to perform control to switch and output at least one of the first optical image 40a (see FIG. 7(A)) and the second optical image 40b (see FIG. 7(B)) to the display unit 13 together with the focus position image 41. Specifically, the image output control unit 30b outputs an image selected from the focus position image 41, the first optical image 40a, and the second optical image 40b to the display unit 13 based on a selection input by the operator inputted by the input receiving unit 6 (see FIG. 1). The display unit 13 displays the image selected by the operator from the focus position image 41, the first optical image 40a, and the second optical image 40b in real time as a moving image.

[0063] (Generation of body movement display image) Here, after the operator positions the subject 90 (see FIG. 2), the subject 90 may move. In this case, the relative positions of the X-ray irradiation unit 10 (see FIG. 1) and the X-ray detector 11 (see FIG. 1) and the subject 90 are displaced from the positioned positions. When the relative positions of the X-ray irradiation unit 10 and the X-ray detector 11 and the subject 90 are displaced, the magnification ratio of the imaging part of the subject 90 in the X-ray image to be taken may change, or the imaging part of the subject 90 may move out of a predetermined area. When the magnification ratio of the imaging part of the subject 90 or the like changes, imaging must be performed again, and the radiation exposure of the subject 90 increases.

[0064] Therefore, in the first embodiment, the image processing unit 30a (see FIG. 1) is configured to generate a body movement amount display image 42 (see FIG. 9(C)), which is an image in which the body movement amount of the subject 90 acquired based on the focus position image 41 (see FIG. 7(C)) is displayed in a visually identifiable manner in the focus position image 41.

[0065] A first focal position image 41a shown in Fig. 9(A) is the focal position image 41 (see Fig. 1) after the positioning of the finger 90c of the subject 90 is completed. A second focal position image 41b shown in Fig. 9(B) is the focal position image 41 after a body movement occurs in the finger 90c of the subject 90 after the positioning. In this way, when a body movement occurs in the finger 90c, which is the imaging part of the subject 90, the image processing unit 30a generates a body movement amount display image 42 shown in Fig. 9(C) based on the first focal position image 41a and the second focal position image 41b.

[0066] Specifically, the image processing unit 30a (see FIG. 1) acquires a contour line 91a of the subject 90 appearing in the first focal position image 41a and a contour line 91b of the subject 90 appearing in the second focal position image 41b. The image processing unit 30a extracts the contour line of the subject 90, for example, by processing using an edge filter or by using a trained model generated by training to extract the contour line of the subject 90.

[0067] The image processor 30a acquires the amount of body movement of the subject 90 based on the distance between corresponding portions of the contour line 91a of the subject 90 in the first focal position image 41a and the contour line 91b of the subject 90 in the second focal position image 41b. If the distance between corresponding portions of the contour line 91a of the subject 90 in the first focal position image 41a and the contour line 91b of the subject 90 in the second focal position image 41b is 0 (zero), or if the distance between corresponding portions of the contour line 91a of the subject 90 in the first focal position image 41a and the contour line 91b of the subject 90 in the second focal position image 41b is equal to or less than a predetermined threshold, the image processor 30a determines that no body movement has occurred in the subject 90.

[0068] In the first embodiment, the image processor 30a generates an image in which the display mode of the area where the body movement occurs is changed according to the body movement amount as the body movement amount display image 42. Specifically, the image processor 30a overlaps the contour line 91b of the second focal position image 41b with the position where the body movement occurs in the first focal position image 41a. Then, the image processor 30a generates the body movement amount display image 42 in which the display mode of the area surrounded by the contour line 91a of the first focal position image 41a and the contour line 91b of the second focal position image 41b is changed as the area where the body movement occurs. In the example shown in FIG. 9(C), the difference in the body movement amount is represented by the area 42a and the area 42b, which are hatched differently from each other. In the example shown in FIG. 9(C), it is shown that the area 42a has a larger body movement amount than the area 42b.

[0069] The image processing unit 30a generates a body movement amount display image 42 as a moving image at a predetermined frame rate. The image output control unit 30b (see FIG. 1) outputs the body movement amount display image 42 as a moving image generated by the image processing unit 30a to the display unit 13 (see FIG. 1). The display unit 13 is configured to display the body movement amount display image 42 as a moving image output by the image output control unit 30b.

[0070] The control unit 30 (see FIG. 1) may be configured to display the body movement amount display image 42 when the subject 90 moves, and to notify the operator that the subject 90 has moved by an alarm sound, an alarm light, or the like.

[0071] (Focus position image generation process) Next, referring to Figure 10, we will explain the process in which the image processing unit 30a (see Figure 1) generates a focus position image 41 (see Figure 7(C)), and the process in which the image output control unit 30b (see Figure 1) outputs the focus position image 41 to the display unit 13 (see Figure 1).

[0072] In step 101, the first optical camera 20a (see FIG. 1) captures a first optical image 40a (see FIG. 7(A)).

[0073] In step 102, the second optical camera 20b (see FIG. 1) captures a second optical image 40b (see FIG. (B)).

[0074] In step 103, the image processing unit 30a generates a focus position image 41 based on the first optical image 40a and the second optical image 40b. The image processing unit 30a may generate the focus position image 41 by combining the first optical image 40a and the second optical image 40b, or may generate the focus position image 41 by inputting the first optical image 40a and the second optical image 40b to the trained model 52 (see FIG. 1).

[0075] In step 104, the image output control unit 30b outputs the focus position image 41 generated in step 103 to the display unit 13. After that, the display unit 13 displays the focus position image 41. Then, the process ends.

[0076] It should be noted that either the process of step 101 or the process of step 102 may be performed first.

[0077] (Output image switching process) Next, with reference to FIG. 11, a process in which the image output control unit 30b (see FIG. 1) switches the image to be output will be described.

[0078] In step 110, the image output control unit 30b acquires the type of image to be output. Specifically, the image output control unit 30b acquires the type of image to be output based on the selection operation of the operator inputted via the input receiving unit 6 (see FIG. 1).

[0079] In step 111, the image output control unit 30b determines whether the type of image to be output is the focus position image 41 (see FIG. 7(C)). If the type of image to be output is the focus position image 41, the process proceeds to step 112. If the type of image to be output is not the focus position image 41, the process proceeds to step 113.

[0080] In step 112, the image output control unit 30b outputs the focus position image 41 to the display unit 13 (see FIG. 1). After that, the display unit 13 displays the focus position image 41. Then, the process ends.

[0081] When the process proceeds from step 111 to step 113, in step 113, the image output control unit 30b determines whether the type of image to be output is the first optical image 40a (see FIG. 7(A)). If the type of image to be output is the first optical image 40a, the process proceeds to step 114. If the type of image to be output is not the first optical image 40a, the process proceeds to step 115.

[0082] In step 114, the image output control unit 30b outputs the first optical image 40a to the display unit 13. After that, the display unit 13 displays the first optical image 40a. Then, the process ends.

[0083] Also, when the process proceeds from step 113 to step 115, in step 115, the image output control unit 30b outputs the second optical image 40b (see FIG. 7(B)) to the display unit 13. After that, the display unit 13 displays the second optical image 40b. Then, the process ends.

[0084] (Display processing of body movement amount display image) Next, referring to Figure 12, we will explain the process in which the image processing unit 30a (see Figure 1) generates a body movement amount display image 42 (see Figure 9(C)) and the image output control unit 30b (see Figure 1) displays the body movement amount display image 42 on the display unit 13 (see Figure 1).

[0085] In step 120, the image processor 30a obtains a first focal position image 41a (see FIG. 9A), which is the focal position image 41 (see FIG. 1) after positioning.

[0086] In step 121, the image processing unit 30a acquires a focus position image 41 of a frame next to the first focus position image 41a. For example, the image processing unit 30a acquires a second focus position image 41b (see FIG. 9(B)) as the focus position image 41 of the next frame.

[0087] In step 122, the image processing unit 30a determines whether or not a body movement has occurred in the imaging site of the subject 90 (see FIG. 2). Specifically, the image processing unit 30a acquires a contour line 91a (see FIG. 9(A)) of the subject 90 captured in the first focal position image 41a acquired in step 120. The image processing unit 30a also acquires a contour line 91b (see FIG. 9(B)) of the subject 90 captured in the second focal position image 41b acquired in step 122. Then, the image processing unit 30a acquires the distance between the corresponding portions of the contour line 91a of the subject 90 captured in the first focal position image 41a and the contour line 91b of the subject 90 captured in the second focal position image 41b. When the distance between the corresponding parts of the contour line 91a of the subject 90 in the first focal position image 41a and the contour line 91b of the subject 90 in the second focal position image 41b is greater than a predetermined threshold, the image processing unit 30a determines that the subject 90 has made a body movement. When the distance between the corresponding parts of the contour line 91a of the subject 90 in the first focal position image 41a and the contour line 91b of the subject 90 in the second focal position image 41b is 0 (zero) or is equal to or less than a predetermined threshold, the image processing unit 30a determines that the subject 90 has not made a body movement. When the subject 90 has made a body movement, the process proceeds to step 123. When the subject 90 has not made a body movement, the process ends.

[0088] In step 123, the image processor 30a acquires the amount of body movement of the subject 90. Specifically, the image processor 30a acquires, as the amount of body movement, the distance between corresponding portions of a contour line 91a of the subject 90 captured in the first focal position image 41a and a contour line 91b of the subject 90 captured in the second focal position image 41b.

[0089] In step 124, the image processing unit 30a generates a body movement amount display image 42. Specifically, the image processing unit 30a changes the display mode of the area where the body movement has occurred according to the amount of body movement acquired in step 123, and overlaps the area with the first focal position image 41a, thereby generating the body movement amount display image 42.

[0090] In step 125, the image output control unit 30b outputs the body movement amount display image 42 to the display unit 13. Thereafter, the display unit 13 displays the body movement amount display image 42. Then, the process ends.

[0091] (Effects of the first embodiment) In the first embodiment, the following effects can be obtained.

[0092] In the first embodiment, as described above, the image processing device 3 is an image processing device that generates an image for positioning the subject 90 in the X-ray imaging device 1, and is equipped with an image acquisition unit 2 including at least one optical camera 20 arranged near the X-ray irradiation unit 10 of the X-ray imaging device 1, and an image processing unit 30a that generates a focal position image 41 based on an optical image 40 captured by the optical camera 20, which is an image of the same field of view as when the subject 90 is captured from the position of the focal point 60 of the X-ray irradiation unit 10, and which is an image that captures an area 63a of the X-ray irradiation range 63, which is the range where X-rays are irradiated by the X-ray irradiation unit 10, and an area 64 outside the X-ray irradiation range 63.

[0093] As a result, the focal position image 41 has the same field of view as when the subject 90 is photographed from the position of the focal point 60 of the X-ray irradiation unit 10, so the focal position image 41 and the X-ray image have the same field of view. In addition, the focal position image 41 includes both the area 63a of the X-ray irradiation range 63 and the area 64 outside the X-ray irradiation range 63, so that it is possible to prevent the field of view of the optical image 40 presented to the operator for positioning the subject 90 from narrowing. As a result, it is possible to present to the operator an image (focal position image 41) that enables accurate positioning of the subject 90 while preventing the field of view of the optical image 40 presented to the operator for positioning the subject 90 from narrowing.

[0094] Furthermore, in the first embodiment, as described above, the X-ray imaging device 1 includes an X-ray irradiation unit 10 that irradiates X-rays, an X-ray detector 11 that detects the X-rays irradiated by the X-ray irradiation unit 10, an image acquisition unit 2 including at least one optical camera 20 arranged in the vicinity of the X-ray irradiation unit 10, and an image processing unit 30a that generates a focal position image 41 based on the optical image 40 captured by the optical camera 20, which is an image of the same field of view as when the subject 90 is photographed from the position of the focal point 60 of the X-ray irradiation unit 10, and which is an image that captures an area 63a of the X-ray irradiation range 63, which is the range where X-rays are irradiated by the X-ray irradiation unit 10, and an area 64 outside the X-ray irradiation range 63.

[0095] This makes it possible to provide an X-ray imaging device 1 that, like the image processing device 3, can present the operator with an image (focal position image 41) that enables accurate positioning of the subject 90 while preventing the field of view of the optical image 40 presented to the operator for positioning the subject 90 from becoming narrow.

[0096] Furthermore, in the first embodiment, as described above, the X-ray imaging system 100 includes an X-ray irradiation unit 10 that irradiates X-rays, an X-ray detector 11 that detects the X-rays irradiated by the X-ray irradiation unit 10, an image acquisition unit 2 that includes at least one optical camera 20 arranged in the vicinity of the X-ray irradiation unit 10, and an image processing unit 30a that generates a focal position image 41 based on the optical image 40 captured by the optical camera 20, which is an image of the same field of view as when the subject 90 is photographed from the position of the focal point 60 of the X-ray irradiation unit 10, and which is an image that includes an area 63a of the X-ray irradiation range 63, which is the range where X-rays are irradiated by the X-ray irradiation unit 10, and an area 64 outside the X-ray irradiation range 63.

[0097] This makes it possible to provide an X-ray imaging system 100 that, like the image processing device 3, can present the operator with an image (focal position image 41) that enables accurate positioning of the subject 90 while preventing the field of view of the optical image 40 presented to the operator for positioning the subject 90 from becoming narrow.

[0098] Furthermore, in the first embodiment, by configuring as follows, the following further effects can be obtained.

[0099] That is, in the first embodiment, as described above, at least one optical camera 20 is provided outside the housing 10d of the collimator 10b included in the X-ray irradiation unit 10, and the image processing unit 30a is configured to generate a focal position image 41 based on an optical image 40 captured by the optical camera 20 provided outside the housing 10d of the collimator 10b. As a result, since at least one optical camera 20 is provided outside the housing 10d of the collimator 10b, unlike a configuration in which optical cameras are provided only inside the housing 10d of the collimator 10b, an optical image 40 in which an area 64 outside the X-ray irradiation range 63 is captured can be easily captured. As a result, an image in which an area 63a of the X-ray irradiation range 63, which is the range in which X-rays are irradiated by the X-ray irradiation unit 10, and an area 64 outside the X-ray irradiation range 63 are captured can be easily acquired, and therefore the focal position image 41 can be easily generated. Furthermore, since the optical camera 20 is provided outside the housing 10d of the collimator 10b, the configuration of the present invention can be easily applied to an X-ray imaging device 1 that has already been installed, compared to a configuration in which the optical camera 20 is provided inside the housing 10d of the collimator 10b.

[0100] In the first embodiment, as described above, the optical camera 20 includes the first optical camera 20a and the second optical camera 20b provided at different positions, the image acquisition unit 2 is configured to acquire the first optical image 40a, which is the optical image 40 captured by the first optical camera 20a, and the second optical image 40b, which is the optical image 40 captured by the second optical camera 20b, and the image processing unit 30a is configured to generate a focus position image 41 based on the first optical image 40a and the second optical image 40b. Here, in the case of a configuration including only one optical camera 20, a blind spot area is generated depending on the arrangement of the optical camera 20. In that case, the focus position image 41 generated based on the optical image 40 does not capture the blind spot area of ​​the optical camera 20. Therefore, by configuring as described above, the first optical camera 20a and the second optical camera 20b are provided at different positions, so that the blind spot area can be reduced compared to a configuration including only one optical camera 20. Therefore, by generating the focus position image 41 based on the first optical image 40a and the second optical image 40b captured by the first optical camera 20a and the second optical camera 20b provided at different positions, it is possible to reduce the area not captured in the focus position image 41 due to the blind spot of the optical camera 20. As a result, it is possible to improve the accuracy of the focus position image 41, and therefore it is possible to perform accurate position adjustment of the subject 90 based on the focus position image 41.

[0101] In the first embodiment, as described above, the first optical camera 20a and the second optical camera 20b are arranged in the vicinity of the X-ray irradiation unit 10 and configured to capture the first optical image 40a and the second optical image 40b, and the image processing unit 30a is configured to generate a focal position image 41 based on the first optical image 40a and the second optical image 40b captured from an oblique direction on one side and an oblique direction on the other side with respect to the position of the focal point 60 of the X-ray irradiation unit 10. As a result, since the first optical camera 20a and the second optical camera 20b are arranged in the vicinity of the X-ray irradiation unit 10, it is possible to reduce the area that is not captured in the focal position image 41 due to the blind spot of the optical camera 20. As a result, it is possible to further improve the accuracy of the focal position image 41.

[0102] In the first embodiment, as described above, the image processor 30a is configured to generate the focal position image 41 by combining the first optical image 40a and the second optical image 40b based on the arrangement information 50 of the first optical camera 20a and the arrangement information 51 of the second optical camera 20b. Here, each of the first optical camera 20a and the second optical camera 20b is arranged at a predetermined angle with respect to the X-ray irradiation axis 61 at a predetermined position of the X-ray irradiation unit 10. That is, the arrangement information 50 of the first optical camera 20a can easily convert the shape of the subject 90 shown in the first optical image 40a with respect to the image captured from the position of the focal point 60 of the X-ray irradiation unit 10. In addition, the arrangement information 51 of the second optical camera 20b can easily deform the shape of the subject 90 shown in the second optical image 40b with respect to the image captured from the position of the focal point 60 of the X-ray irradiation unit 10. As a result, the focus position image 41 can be easily generated based on the first optical image 40a and the second optical image 40b, and the position information 50 of the first optical camera 20a and the position information 51 of the second optical camera 20b.

[0103] In the first embodiment, as described above, the image processing unit 30a is configured to generate a focal position image 41 based on the trained model 52, which is generated by training the model 52 to generate an image of the same field of view as when the subject 90 is imaged from the position of the X-ray focal point 60 from a plurality of optical images 40 captured from different oblique directions, and the first optical image 40a and the second optical image 40b. This makes it possible to easily generate the focal position image 41 by inputting the first optical image 40a and the second optical image 40b to the trained model 52.

[0104] In the first embodiment, as described above, the image output control unit 30b is further provided, which controls the output of the focus position image 41 to the display unit 13, and the image output control unit 30b is configured to control the switching of at least one of the first optical image 40a and the second optical image 40b together with the focus position image 41 to be output to the display unit 13. Here, the operator positions the subject 90 at a position on one side of the top board 4. Therefore, it is difficult to confirm the position of the subject 90 from a position on the opposite side of the top board 4. Therefore, as described above, by configuring the focus position image 41, the first optical image 40a, and the second optical image 40b to be output to the display unit 13 by switching, the operator can confirm the optical image 40 taken by the optical camera 20 provided at a position opposite to the operator. As a result, the operator can confirm the optical image 40 taken from a position opposite to the operator, and therefore the convenience (usability) of the operator when positioning the subject 90 can be improved.

[0105] Furthermore, in the first embodiment, as described above, the image processor 30a is configured to generate a body movement amount display image 42, which is an image in which the body movement amount of the subject 90 acquired based on the focus position image 41 is displayed in a visually identifiable manner in the focus position image 41. Thus, by presenting the body movement amount display image 42 to the operator, the operator can intuitively and easily grasp the body movement amount of the subject 90. As a result, the operator can easily adjust the position of the subject 90, and the burden on the operator associated with adjusting the position of the subject 90 can be reduced.

[0106] In the first embodiment, as described above, the X-ray imaging device 1 further includes a collimator 10b that adjusts the irradiation range 63 of the X-rays irradiated from the X-ray irradiation unit 10, the optical camera 20 includes a first optical camera 20a and a second optical camera 20b that are provided at different positions from each other, and the first optical camera 20a and the second optical camera 20b are provided outside the housing 10d of the collimator 10b so as to be located near the X-ray irradiation unit 10, the image acquisition unit 2 is configured to acquire a first optical image 40a that is the optical image 40 captured by the first optical camera 20a and a second optical image 40b that is the optical image 40 captured by the second optical camera 20b, and the image processing unit 30a is configured to generate a focal position image 41 based on the first optical image 40a and the second optical image 40b captured from an oblique direction on one side and an oblique direction on the other side, based on the position of the focal point 60 of the X-ray irradiation unit 10 as a reference. As a result, since the first optical camera 20a and the second optical camera 20b are disposed in the vicinity of the X-ray irradiation unit 10, it is possible to reduce an area that is not captured in the focal position image 41 due to a blind spot of the optical camera 20. As a result, it is possible to provide an X-ray imaging device 1 that can further improve the accuracy of the focal position image 41.

[0107] [Second embodiment] An X-ray imaging system 200 including an image processing device 201 according to the second embodiment will be described with reference to Fig. 13 and Fig. 14. Unlike the configuration of the first embodiment in which the first optical camera 20a (see Fig. 3) and the second optical camera 20b (see Fig. 3) are arranged outside the housing 10d (see Fig. 3) of the collimator 10b, the X-ray imaging system 200 including the image processing device 201 according to the second embodiment has at least one of the first optical camera 20a and the second optical camera 20b provided inside the housing 10d (see Fig. 14) of the collimator 10b, and the other provided outside the housing 10d of the collimator 10b. Note that the same reference numerals are used for the same configuration as the X-ray imaging system 100 (see Fig. 1) according to the first embodiment, and detailed description thereof will be omitted.

[0108] The X-ray imaging system 200 according to the second embodiment differs from the X-ray imaging system 100 according to the first embodiment in that an image processing device 201 is provided instead of the image processing device 3 (see FIG. 1).

[0109] The image processing device 201 according to the second embodiment differs from the image processing device 3 according to the first embodiment in that it includes a control unit 230 and a storage unit 231 instead of the control unit 30 (see FIG. 1) and the storage unit 31 (see FIG. 1).

[0110] The control unit 230 according to the second embodiment differs from the control unit 30 according to the first embodiment in that an image processing unit 230a is provided instead of the image processing unit 30a (see FIG. 1).

[0111] The storage unit 231 according to the second embodiment differs from the storage unit 31 according to the first embodiment in that it does not store the arrangement information 50 (see FIG. 1) of the first optical camera 20a.

[0112] The image processing unit 230a according to the second embodiment differs from the image processing unit 30a according to the first embodiment in that it generates a focus position image 41 based on a first optical image 40a captured by a first optical camera 20a provided within the housing 10d of the collimator 10b and a second optical image 40b captured by a second optical camera 20b provided outside the housing 10d of the collimator 10b.

[0113] (Optical camera placement) As shown in Fig. 14, the first optical camera 20a according to the second embodiment is provided in a position conjugate with the focal point 60 of the X-rays inside the housing 10d of the collimator 10b. That is, the first optical camera 20a is arranged inside the housing 10d of the collimator 10b and configured to capture the first optical image 40a from a position conjugate with the focal point 60 of the X-rays. In addition, in the second embodiment, an optical member 21 is provided on the irradiation axis 61 of the X-rays and at a position facing the first optical camera 20a. The optical member 21 includes, for example, a half mirror and is configured to form an image of the imaging site of the subject 90 (see Fig. 15) at a position conjugate with the focal point 60 of the X-rays.

[0114] In the second embodiment, the second optical camera 20b is provided outside the housing 10d of the collimator 10b. The second optical camera 20b captures an image of the subject 90 from an oblique direction with respect to the irradiation axis 61 along the direction indicated by the arrow 80b. That is, the second optical camera 20b is disposed at a position outside the housing 10d of the collimator 10b and configured to capture the second optical image 40b.

[0115] In the second embodiment, the image processing unit 230a (see FIG. 13) is configured to generate a focal position image 41 (see FIG. 15) based on a first optical image 40a taken from a position conjugate with the X-ray focal point 60 and a second optical image 40b taken from outside the housing 10d of the collimator 10b.

[0116] The focal position image 41 shown in Fig. 15 is an image displayed on the display unit 13 (see Fig. 13) when the image processor 230a (see Fig. 13) according to the second embodiment captures an image of the ankle of the subject 90 as a body part to be photographed. In the focal position image 41 shown in Fig. 15, a rectangle illustrated by a dashed line is an X-ray irradiation range 63 irradiated from the X-ray irradiation unit 10 (see Fig. 13). Moreover, an area 64 is an area outside the area 63a of the X-ray irradiation range 63. Moreover, a crosshair 62 is a line serving as a guide for positioning, irradiated onto the detection surface of the X-ray detector 11 by a projection lamp 10c (see Fig. 13) arranged at a position conjugate with the X-ray focal point 60 (see Fig. 14).

[0117] In the second embodiment, the image processing unit 230a is configured to generate an image of a region 63a of the X-ray irradiation range 63 in the focus position image 41 based on an optical image 40 taken from a position conjugate with the X-ray focus 60, and to generate an image of a region outside the X-ray irradiation range 63 in the focus position image 41 based on an optical image 40 taken from outside the housing 10d of the collimator 10b.

[0118] Here, the image of the region 63a of the X-ray irradiation range 63 is an image captured from a position conjugate with the X-ray focal point 60, and therefore is an image of the same field of view as the image captured from the X-ray focal point 60. Specifically, the image of the region 63a of the X-ray irradiation range 63 is the first optical image 40a.

[0119] On the other hand, the image of the area 64 outside the area 63a of the X-ray irradiation range 63 is the second optical image 40b taken from an oblique direction by the second optical camera 20b, and therefore the subject 90 is depicted differently in the first optical image 40a and the second optical image 40b.

[0120] Therefore, the image processing unit 230a according to the second embodiment transforms the second optical image 40b based on the arrangement information 51 of the second optical camera 20b stored in the storage unit 231 (see FIG. 13). For example, the image processing unit 230a transforms the second optical image 40b by projective transformation. Then, the image processing unit 230a acquires a portion of the second optical image 40b after the projective transformation outside the region 63a of the X-ray irradiation range 63 as an image of a region 64 outside the region 63a of the X-ray irradiation range 63. Note that the image processing unit 230a may be configured to transform the second optical image 40b by affine transformation.

[0121] Then, the image processor 230a generates the focal position image 41 by combining the image of the region 63a of the X-ray irradiation range 63 with the image of the region 64 outside the region 63a of the X-ray irradiation range 63. Therefore, the image of the region 63a of the X-ray irradiation range 63 in the focal position image 41 accurately shows the shape of the imaging part of the subject 90. On the other hand, the image of the region 64 outside the region 63a of the X-ray irradiation range 63 may have distortion because the shape of the imaging part of the subject 90 is transformed by projective transformation, but the field of view of the focal position image 41 can be expanded. Therefore, the focal position image 41 according to the second embodiment is an image with an expanded field of view while maintaining the accuracy of the region 63a of the X-ray irradiation range 63.

[0122] (Generation of focal position image) Next, a configuration in which the image processing unit 230a (see FIG. 13) according to the second embodiment generates a focus position image 41 (see FIG. 15) will be described with reference to FIG. 16. Note that the same reference numerals are used for processes similar to those by the image processing unit 30a (see FIG. 1) and the image output control unit 30b (see FIG. 1) according to the first embodiment, and detailed descriptions thereof will be omitted.

[0123] In step 105, the first optical camera 20a (see FIG. 14) acquires a first optical image 40a (see FIG. 13). Note that the first optical image 40a acquired in step 105 is the optical image 40 (see FIG. 13) captured by the first optical camera 20a arranged at a position conjugate with the X-ray focal point 60 (see FIG. 14) inside the housing 10d (see FIG. 14) of the collimator 10b (see FIG. 14).

[0124] In step 102, the second optical camera 20b (see FIG. 13) captures a second optical image 40b (see FIG. 13).

[0125] In step 106, the image processing unit 230a generates a focal position image 41 (see FIG. 15) based on the first optical image 40a acquired in step 105 and the second optical image 40b acquired in step 102. Specifically, the image processing unit 230a generates the focal position image 41 by synthesizing an image of a region 63a in the X-ray irradiation range 63 acquired by the first optical camera 20a and an image of a region 64 outside the region 63a in the X-ray irradiation range 63 acquired by the second optical camera 20b and subjected to transformation processing such as projective transformation.

[0126] In step 104, the image output control unit 30b (see FIG. 13) outputs the focus position image 41 generated in step 106 to the display unit 13 (see FIG. 13). The display unit 13 displays the focus position image 41. After that, the process ends.

[0127] It should be noted that either the process of step 105 or the process of step 102 may be performed first.

[0128] Other configurations of the second embodiment are similar to those of the first embodiment.

[0129] (Effects of the second embodiment) In the second embodiment, as described above, the first optical camera 20a is arranged inside the housing 10d of the collimator 10b and configured to capture the first optical image 40a from a position conjugate with the X-ray focal point 60, the second optical camera 20b is arranged at a position outside the housing 10d of the collimator 10b and configured to capture the second optical image 40b, and the image processing unit 230a is configured to generate a focal position image 41 based on the first optical image 40a captured from a position conjugate with the X-ray focal point 60 and the second optical image 40b captured from outside the housing 10d of the collimator 10b. As a result, the image processing unit 230a generates a focal position image 41 based on the first optical image 40a captured from a position conjugate with the X-ray focal point 60 and the second optical image 40b captured from outside the housing 10d of the collimator 10b, and therefore, unlike a configuration in which the optical camera 20 is disposed only inside the housing 10d of the collimator 10b, it is possible to generate a focal position image 41 that captures not only the area 63a of the X-ray irradiation range 63 but also an area 64 outside the X-ray irradiation range 63. As a result, compared to a configuration including only one optical camera 20, it is possible to increase the area captured in the focal position image 41, making it easier for the operator to position the subject 90.

[0130] In the second embodiment, as described above, the image processor 230a is configured to generate an image of the region 63a of the X-ray irradiation range 63 in the focal position image 41 based on the optical image 40 captured from a position conjugate with the focal point 60 of the X-ray, and generate an image of the region outside the X-ray irradiation range 63 in the focal position image 41 based on the optical image 40 captured from the outside of the housing 10d of the collimator 10b. Here, the second optical camera 20b provided outside the housing 10d of the collimator 10b captures images from an oblique direction with respect to the X-ray irradiation axis 61 of the X-ray irradiation unit 10. Therefore, the subject 90 captured in the second optical image 40b captured by the second optical camera 20b has a different field of view from the optical image 40 captured from the position of the focal point 60 of the X-ray irradiation unit 10. Furthermore, the first optical image 40a captured by the first optical camera 20a provided at a position conjugate with the X-ray focal point 60 inside the housing 10d of the collimator 10b can be regarded as the optical image 40 captured from the position of the focal point 60 of the X-ray irradiation unit 10, so no distortion occurs in the shape of the subject 90. However, since the first optical camera 20a is provided inside the housing 10d of the collimator 10b, the area captured in the first optical image 40a is limited by the collimator 10b.

[0131] Therefore, as described above, the image processor 230a is configured to generate the focal position image 41 based on the first optical image 40a captured from a position conjugate with the focal point 60 of the X-rays and the second optical image 40b captured from outside the housing 10d of the collimator 10b. Since the first optical image 40a is captured from a position conjugate with the focal point 60 of the X-rays, the first optical image 40a has the same field of view as the image captured from a direction along the irradiation axis 61 of the X-rays. Therefore, it is possible to prevent distortion of the shape of the subject 90 captured in the first optical image 40a. In addition, since the second optical image 40b is captured by the second optical camera 20b provided outside the housing 10d of the collimator 10b, the second optical image 40b captures the area 63a of the X-ray irradiation range 63 and the area 64 outside the area 63a of the X-ray irradiation range 63. Therefore, the field of view captured in the focal position image 41 can be enlarged. As a result, it is possible to suppress a decrease in accuracy of the portion of the focal position image 41 that corresponds to the region 63a of the X-ray irradiation range 63, while increasing the field of view captured in the entire image.

[0132] In the second embodiment, as described above, the X-ray imaging device 1 further includes a collimator 10b that adjusts the irradiation range 63 of the X-rays irradiated from the X-ray irradiation unit 10, and the optical camera 20 includes a first optical camera 20a and a second optical camera 20b that are provided at different positions, one of the first optical camera 20a and the second optical camera 20b is provided at a position conjugate with the focal point 60 of the X-rays inside the housing 10d of the collimator 10b, and the other of the first optical camera 20a and the second optical camera 20b is provided outside the housing 10d of the collimator 10b, and the image processing unit 230a is configured to generate a focal position image 41 based on the optical image 40 captured from a position conjugate with the focal point 60 of the X-rays and the optical image 40 captured from outside the housing 10d of the collimator 10b. As a result, the image processor 30a generates the focal position image 41 based on the first optical image 40a captured from a position conjugate with the X-ray focal point 60 and the second optical image 40b captured from outside the housing 10d of the collimator 10b, and therefore, unlike a configuration in which the optical camera 20 is disposed only inside the housing 10d of the collimator 10b, it is possible to generate a focal position image 41 that captures an area 63a of the X-ray irradiation range 63 as well as an area 64 outside the X-ray irradiation range 63. Therefore, compared to a configuration including only one optical camera 20, it is possible to increase the field of view captured in the focal position image 41. As a result, it is possible to provide an X-ray imaging device 1 that allows the operator to more easily position the subject 90.

[0133] Other effects of the second embodiment are similar to those of the first embodiment.

[0134] [Third embodiment] 17 and 18, an X-ray imaging system 300 including an image processing device 301 and an image acquiring unit 302 according to the third embodiment will be described. Unlike the X-ray imaging system 100 (see FIG. 1) according to the first embodiment in which the image acquiring unit 2 (see FIG. 1) includes a first optical camera 20a and a second optical camera 20b, the image acquiring unit 302 included in the X-ray imaging system 300 according to the third embodiment includes only one optical camera 20. Note that the same components as those in the X-ray imaging system 100 according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0135] The X-ray imaging system 300 according to the third embodiment differs from the X-ray imaging system 100 according to the first embodiment in that it has an image processing device 301 instead of the image processing device 3 (see FIG. 1) and an image acquisition unit 302 instead of the image acquisition unit 2 (see FIG. 1).

[0136] The image processing device 301 according to the third embodiment differs from the image processing device 3 according to the first embodiment in that it includes a control unit 330 and a storage unit 331 instead of the control unit 30 (see FIG. 1) and the storage unit 31 (see FIG. 1).

[0137] The image acquisition section 302 according to the third embodiment differs from the image acquisition section 2 according to the first embodiment in that it includes only one optical camera 20.

[0138] The control unit 330 according to the third embodiment differs from the control unit 30 according to the first embodiment in that an image processing unit 330a is provided instead of the image processing unit 30a (see FIG. 1).

[0139] The image processing unit 330a according to the third embodiment differs from the image processing unit 30a according to the above embodiment in that the image processing unit 330a generates a focus position image 41 from one optical image .

[0140] The storage unit 331 according to the third embodiment differs from the storage unit 31 according to the first embodiment in that it does not store a trained model 52 (see FIG. 1) and stores arrangement information 53 of the optical camera 20 instead of the arrangement information 50 of the first optical camera 20a (see FIG. 1) and the arrangement information 51 of the second optical camera 20b (see FIG. 1). The arrangement information 53 of the optical camera 20 includes the distance in the X direction and the distance in the Y direction from the focal point 60 of the X-rays (see FIG. 3) to the optical camera 20, and the angle of the optical axis of the optical camera 20 with respect to the irradiation axis 61.

[0141] In the third embodiment, the image acquisition unit 302 includes only one optical camera 20 arranged outside the housing 10d (see FIG. 3) of the collimator 10b. Therefore, the image processing unit 330a generates the focus position image 41 based on only one optical image 40. For example, the image processing unit 330a according to the third embodiment generates the focus position image 41 based on the arrangement information 53 of the optical camera 20 stored in the storage unit 331. Specifically, the image processing unit 330a generates the focus position image 41 by performing projective transformation on the optical image 40 using the arrangement information 53 of the optical camera 20. The image processing unit 330a may be configured to generate the focus position image 41 by performing affine transformation on the optical image 40. The arrangement of the one optical camera 20 is the same as any of the arrangements of the first optical camera 20a according to the first embodiment, the second optical camera 20b according to the first embodiment, and the second optical camera 20b according to the second embodiment.

[0142] Next, a configuration in which the image processing unit 330a (see FIG. 17) according to the third embodiment generates a focus position image 41 (see FIG. 17) will be described with reference to Fig. 18. Note that the same reference numerals are used for processes similar to those by the image processing unit 30a (see FIG. 1) and the image output control unit 30b (see FIG. 1) according to the first embodiment, and detailed descriptions thereof will be omitted.

[0143] In step 107, the optical camera 20 (see FIG. 17) acquires an optical image 40 (see FIG. 17). Note that the optical image 40 acquired in step 107 is an optical image 40 captured by the optical camera 20 disposed outside the housing 10d (see FIG. 3) of the collimator 10b (see FIG. 1).

[0144] In step 108, the image processing unit 330a (see FIG. 17) generates a focus position image 41 based on the optical image 40 acquired in step 107 and the arrangement information 53 (see FIG. 17) of the optical camera 20 stored in the storage unit 331 (see FIG. 17). Specifically, the image processing unit 330a generates the focus position image 41 by performing projective transformation on the optical image 40 acquired by the optical camera 20.

[0145] In step 104, the image output control unit 30b (see FIG. 17) outputs the focus position image 41 generated in step 106 to the display unit 13 (see FIG. 17). The display unit 13 displays the focus position image 41. After that, the process ends.

[0146] Other configurations of the third embodiment are similar to those of the first embodiment.

[0147] (Effects of the third embodiment) In the third embodiment, as described above, the image acquisition unit 302 includes one optical camera 20, and the image processing unit 330a is configured to generate a focal position image 41 based on one optical image 40 and the arrangement information 53 of the optical camera 20. This makes it possible to reduce the number of optical cameras 20 included in the image acquisition unit 2, as compared with the X-ray imaging system 100 according to the first embodiment and the X-ray imaging system 200 according to the second embodiment. As a result, it is possible to present to the operator an image (focal position image 41) that enables accurate positioning of the subject 90, while suppressing an increase in the number of parts.

[0148] Other effects of the third embodiment are similar to those of the first embodiment.

[0149] [Variations] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims, not by the description of the embodiments above, and further includes all modifications (variations) within the meaning and scope of the claims.

[0150] For example, in the above-described first embodiment, an example of a configuration in which the image processing unit 30a generates a focal position image 41 based on a trained model 52 generated by learning to generate an image of the same field of view as when the subject 90 is photographed from the position of the X-ray focal point 60 from a plurality of optical images 40 photographed from different oblique directions is shown, but the present invention is not limited to this. For example, as in an X-ray imaging system 400 according to a modified example of the first embodiment shown in Fig. 19, the focal position image 41 may be generated based on a common feature point 65 (see Fig. 20) that appears in the first optical image 40a and the second optical image 40b.

[0151] An X-ray imaging system 400 according to a modified example of the first embodiment differs from the X-ray imaging system according to the first embodiment in that an image processing device 401 is provided instead of the image processing device 3. The image processing device 401 differs from the image processing device 3 according to the first embodiment in that a control unit 430 and a storage unit 431 are provided instead of the control unit 30 and the storage unit 31.

[0152] The control unit 430 differs from the control unit 30 according to the first embodiment in that it includes an image processing unit 430a instead of the image processing unit 30a. The storage unit 431 also differs from the storage unit 31 according to the first embodiment in that it stores a trained model 452 instead of the trained model 52 and further stores a parallax image 43.

[0153] The trained model 452 is a trained model that has been generated by training to generate a disparity image 43 in which a subject appearing in an optical image 40 is imaged using pixel values ​​that are changed based on differences in the depth direction.

[0154] The parallax image 43 is an image in which the difference in the depth direction of the subject captured in the image is pixelated. The parallax image 43 includes a first parallax image 43a and a second parallax image 43b. The first parallax image 43a is a parallax image 43 generated by the trained model 452 based on the first optical image 40a. The second parallax image 43b is a parallax image 43 generated by the trained model 452 based on the second optical image 40b. The first parallax image 43a and the second parallax image 43b will be described in detail later.

[0155] The image processing unit 430a differs from the image processing unit 30a according to the first embodiment described above in that the image processing unit 430a generates a focus position image 41 based on a first optical image 40a, a second optical image 40b, and a first parallax image 43a and a second parallax image 43b generated based on a trained model 452.

[0156] With reference to FIG. 20, a configuration in which the image processing unit according to the comparative example generates a focal position image 41 based on a feature point 65 captured in the first optical image 40a and a feature point 65 captured in the second optical image 40b will be described. Specifically, the image processing unit according to the comparative example detects corresponding feature points 65 in the first optical image 40a and the second optical image 40b. In FIG. 20, the corresponding feature points 65 are illustrated as being connected by a straight line 65a. Then, the image processing unit according to the comparative example calculates the parallax of the corresponding feature points 65, and generates an image captured from an arbitrary position between the first optical camera 20a and the second optical camera 20b that captured the two optical images 40, based on the calculated parallax. That is, the image processing unit according to the comparative example generates a focal position image 41 that is an image captured from the position of the focal point 60 of the X-ray irradiation unit 10 between the first optical camera 20a and the second optical camera 20b.

[0157] Here, pattern matching and the like can be considered as a method for detecting corresponding feature points 65 in the first optical image 40a and the second optical image 40b. However, since the first optical camera 20a and the second optical camera 20b are optical cameras 20 arranged at different positions, the subjects captured in the first optical image 40a and the second optical image 40b are captured from different viewpoints. Therefore, the accuracy of detecting the corresponding feature points 65 in the first optical image 40a and the second optical image 40b decreases.

[0158] Therefore, in a modified example of the first embodiment, the image processing unit 430a (see FIG. 19) is configured to acquire the parallax between the first optical image 40a and the second optical image 40b based on the trained model 452 (see FIG. 19), and to generate a focus position image 41 based on the parallax between the acquired first optical image 40a and second optical image 40b.

[0159] Specifically, as shown in FIG. 21, the image processing unit 430a generates the first parallax image 43a and the second parallax image 43b based on the trained model 452 (see FIG. 19). The first parallax image 43a and the second parallax image 43b are images that are imaged by pixel values ​​according to differences in the depth direction, as shown in the legend 70. Specifically, the first parallax image 43a and the second parallax image 43b are images in which the pixel values ​​are higher on the near side in the depth direction and the pixel values ​​are lower on the far side in the depth direction. In other words, in each of the first parallax image 43a and the second parallax image 43b, the pixel values ​​of the subject closer to the X-ray irradiation unit 10 (see FIG. 19) are higher, and the pixel values ​​are lower as the subject moves away from the X-ray irradiation unit 10.

[0160] 21, in the first parallax image 43a, the pixel value of the head 90b of the subject 90 is the highest, followed by the ears 90d and chest 90e of the subject 90, the X-ray detector 11, the detector holding section 15a, and the detector holding member 15b in that order. Also in the second parallax image 43b, the pixel value of the head 90b of the subject 90 is the highest, followed by the ears 90d and chest 90e of the subject 90, the X-ray detector 11, the detector holding section 15a, and the detector holding member 15b in that order.

[0161] Furthermore, when comparing the first parallax image 43a and the second parallax image 43b, the pixel values ​​of the second parallax image 43b are generally higher due to the difference in the positioning of the first optical camera 20a (see FIG. 19) and the second optical camera 20b (see FIG. 19).

[0162] The image processing unit 430a according to the modification of the first embodiment acquires the parallax of corresponding feature points 65 (see FIG. 20) in the first optical image 40a (see FIG. 20) and the second optical image 40b (see FIG. 20) based on the difference in parallax between the first parallax image 43a and the second parallax image 43b. This improves the accuracy of detecting the corresponding feature points 65 in the first optical image 40a and the second optical image 40b, so that the image processing unit 430a can generate a highly accurate focus position image 41.

[0163] Next, a process in which an image processing unit 430a (see FIG. 19) according to a modified example of the first embodiment generates a focus position image 41 (see FIG. 20) will be described with reference to Fig. 22. Note that the same processes as those by the image processing unit 30a (see FIG. 1) and the image output control unit 30b (see FIG. 1) according to the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

[0164] In steps 101 and 102, the first optical camera 20a (see FIG. 19) and the second optical camera 20b (see FIG. 19) acquire a first optical image 40a (see FIG. 20) and a second optical image 40b (see FIG. 20).

[0165] In step 130, the image processing unit 430a acquires a first parallax image 43a (see FIG. 21) and a second parallax image 43b (see FIG. 21). Specifically, the image processing unit 430a generates the first parallax image 43a by inputting the first optical image 40a to a trained model 452 (see FIG. 19). Also, the image processing unit 430a generates the second parallax image 43b by inputting the second optical image 40b to the trained model 452.

[0166] In step 131, the image processing unit 430a generates a focus position image 41 based on the first optical image 40a, the second optical image 40b, the first parallax image 43a, and the second parallax image 43b. Specifically, the image processing unit 430a acquires corresponding feature points 65 (see FIG. 20) in the first optical image 40a and the second optical image 40b. At this time, the image processing unit 430a acquires a difference (difference in the depth direction) between pixel values ​​of pixels corresponding to the feature points 65 in the first parallax image 43a and the second parallax image 43b as the parallax of the feature points 65. Then, the image processing unit 430a generates the focus position image 41 based on the acquired feature points 65.

[0167] In step 104, the image output control unit 30b (see FIG. 19) outputs the focus position image 41 generated in step 131 to the display unit 13 (see FIG. 19). The display unit 13 displays the focus position image 41. After that, the process ends.

[0168] Other configurations of the modified example of the first embodiment are similar to those of the first embodiment.

[0169] As described above, the image processing unit 430a according to the modification of the first embodiment can generate an image similar to an image captured from an arbitrary position between the first optical camera 20a and the second optical camera 20b using the first optical image 40a, the second optical image 40b, the first parallax image 43a, and the second parallax image 43b. Therefore, it is possible to present an image captured from an arbitrary position between the first optical camera 20a and the second optical camera 20b to the operator without capturing an image while moving the optical camera 20 at a position between the first optical camera 20a and the second optical camera 20b. As a result, it is possible to improve the convenience (usability) of the operator. Moreover, the image processing unit 430a according to the modification of the first embodiment generates a focus position image 41 using the first optical image 40a, the second optical image 40b, the first parallax image 43a, and the second parallax image 43b. Therefore, in the X-ray imaging system 400, similarly to the X-ray imaging system 100 according to the first embodiment described above, it is possible to present to the operator an image (focal position image 41) that enables accurate positioning of the subject 90 while preventing the field of view of the optical image 40 presented to the operator in order to position the subject 90 from becoming narrow.

[0170] In the first to third embodiments, the X-ray imaging system includes an image acquisition unit and an image processing device as different devices, but the present invention is not limited to this. For example, as in an X-ray imaging system 500 according to a first modification shown in FIG. 23, the image acquisition unit 2 may be included in the image processing device 401. That is, the X-ray imaging system 500 according to the first modification includes an X-ray imaging device 1 and an image processing device 401 including the image acquisition unit 2. The X-ray imaging device 1 has the same configuration as in the first to third embodiments. The image processing device 401 has the same configuration as the image processing device according to any one of the first and second embodiments, except that it includes the image acquisition unit 2. The image acquisition unit 2 has the same configuration as the image acquisition unit according to any one of the image acquisition units 2 according to the first and second embodiments.

[0171] In the first to third embodiments, the X-ray imaging device 1, the image acquisition unit 2, and the image processing device 3 are included in the X-ray imaging system, but the present invention is not limited to this. For example, as in the X-ray imaging device 600 according to the second modified example shown in FIG. 24, the X-ray imaging device 600 may be configured to include the image acquisition unit 2 and the control unit 601 including the image processing unit 601a and the image output control unit 30b. The control unit 601 has the same configuration as the device control unit 12 according to the first to third embodiments and the control unit included in the image processing device according to the first and second embodiments. That is, the control unit 601 may be configured to include both the functions of the device control unit 12 and the control unit of the image processing device shown in the first to third embodiments. In this case, the X-ray imaging device 600 may be configured to further include the top board 4, the top board movement mechanism 5, the input reception unit 6, and the storage unit 31.

[0172] In the above first to third embodiments, an example of a configuration in which the image processing unit generates the body movement amount display image 42 has been shown, but the present invention is not limited to this. The image processing unit does not have to generate the body movement amount display image 42. However, if the image processing unit does not generate the body movement amount display image 42, it becomes difficult for the operator to easily grasp the body movement of the subject 90 at a glance. For this reason, it is preferable that the image processing unit is configured to generate the body movement amount display image 42.

[0173] In the above first to third embodiments, an example of a configuration has been shown in which the image processing unit generates an image in which the display mode of the area between the corresponding parts of the contour line 91a of the first focal position image 41a and the contour line 91b of the second focal position image 41b is changed as the body movement amount display image 42, but the present invention is not limited to this. For example, the image processing unit may be configured to change the transparency of either the first focal position image 41a or the second focal position image 41b and generate an image in which the images are superimposed on each other as the body movement amount display image.

[0174] In the above first embodiment, the first optical camera 20a is provided on the Y1 direction side with respect to the X-ray focal point 60, and the second optical camera 20b is provided on the Y2 direction side with respect to the X-ray focal point 60, but the present invention is not limited to this. As long as the first optical camera 20a and the second optical camera 20b are provided at symmetrical positions with respect to the X-ray focal point 60, the arrangement of the first optical camera 20a and the second optical camera 20b does not matter. For example, the first optical camera 20a may be provided on the Y2 direction side with respect to the X-ray focal point 60, and the second optical camera 20b may be provided on the Y1 direction side with respect to the X-ray focal point 60. Also, the first optical camera 20a and the second optical camera 20b may be provided at symmetrical positions in the Z direction with respect to the X-ray focal point 60.

[0175] In the first embodiment, the first optical camera 20a and the second optical camera 20b are provided outside the housing 10d of the collimator 10b so as to be symmetrical with respect to the focal point 60 of the X-ray irradiation unit 10, but the present invention is not limited to this. The first optical camera 20a and the second optical camera 20b do not have to be arranged symmetrically with respect to the focal point 60 as long as they are located near the X-ray irradiation unit 10. The positional relationship between the first optical camera 20a and the second optical camera 20b and the focal point 60 is known. Therefore, even if the first optical camera 20a and the second optical camera 20b are not arranged symmetrically with respect to the focal point 60, the focal point position image 41 may be generated by synthesizing the first optical image 40a and the second optical image 40b with respect to the calculated parallax at a ratio based on the positional relationship between the optical cameras 20 and the focal point 60.

[0176] In the above first to third embodiments, for convenience of explanation, the process in which the image processing unit of the present invention generates the focus position image 41 and the body movement amount display image 42, and the process in which the image output control unit 30b outputs the focus position image 41, the first optical image 40a, and the second optical image 40b are described using a flow-driven flowchart in which the process is performed in order according to the processing flow, but the present invention is not limited to this. In the present invention, the process in which the image processing unit generates the focus position image 41 and the body movement amount display image 42, and the process in which the image output control unit 30b outputs the focus position image 41, the first optical image 40a, and the second optical image 40b may be performed by event-driven processing in which processing is performed on an event-by-event basis. In this case, the process may be completely event-driven, or event-driven and flow-driven may be combined.

[0177] [Aspects] It will be appreciated by those skilled in the art that the exemplary embodiments described above are examples of the following aspects.

[0178] (Item 1) 1. An image processing device for generating an image for positioning a subject in an X-ray imaging device, an image acquisition unit including at least one optical camera disposed near an X-ray irradiation unit of the X-ray imaging device; and an image processing unit that generates, based on the optical image captured by the optical camera, a focal position image, which has the same field of view as an image of the subject captured from the position of the focal point of the X-ray irradiation unit and which includes an area of ​​the X-ray irradiation range, which is the range where X-rays are irradiated by the X-ray irradiation unit, and an area outside the X-ray irradiation range.

[0179] (Item 2) At least one of the optical cameras is provided outside a housing of a collimator included in the X-ray irradiation unit, 2. The image processing device according to claim 1, wherein the image processing unit is configured to generate the focal position image based on the optical image captured by the optical camera provided outside the housing of the collimator.

[0180] (Item 3) The optical camera includes a first optical camera and a second optical camera provided at different positions from each other, the image acquisition unit is configured to acquire a first optical image that is the optical image captured by the first optical camera and a second optical image that is the optical image captured by the second optical camera, 3. The image processing device according to item 2, wherein the image processing unit is configured to generate the focus position image based on the first optical image and the second optical image.

[0181] (Item 4) the first optical camera and the second optical camera are disposed at positions near the X-ray irradiation unit and configured to capture the first optical image and the second optical image; 4. The image processing device according to item 3, wherein the image processing unit is configured to generate the focal position image based on the first optical image and the second optical image taken from an oblique direction on one side and an oblique direction on the other side, based on the position of the focal point of the X-ray irradiation unit.

[0182] (Item 5) 5. The image processing device according to item 4, wherein the image processing unit is configured to generate the focus position image by combining the first optical image and the second optical image based on position information of the first optical camera and position information of the second optical camera.

[0183] (Item 6) The image processing device according to any one of items 3 to 5, wherein the image processing unit is configured to generate the focal position image based on a trained model generated by training the device to generate an image of the same field of view as when the subject is photographed from the position of the X-ray focal point from a plurality of the optical images photographed from different oblique directions, the first optical image, and the second optical image.

[0184] (Item 7) an image output control unit that controls output of the focus position image to a display unit, The image processing device according to any one of items 3 to 6, wherein the image output control unit is configured to perform control to switch between and output at least one of the first optical image and the second optical image together with the focus position image to the display unit.

[0185] (Item 8) the first optical camera is disposed inside the housing of the collimator and configured to capture the first optical image from a position conjugate with a focal point of X-rays, and the second optical camera is disposed at a position outside the housing of the collimator and configured to capture the second optical image; The image processing device according to any one of items 3 to 7, wherein the image processing unit is configured to generate the focal position image based on the first optical image taken from a position conjugate with a focal point of X-rays and the second optical image taken from outside the housing of the collimator.

[0186] (Item 9) 9. The image processing device according to item 8, wherein the image processing unit is configured to generate an image of a region of the X-ray irradiation range in the focal position image based on the optical image taken from a position conjugate with the X-ray focus, and to generate an image of a region of the focal position image outside the X-ray irradiation range based on the optical image taken from outside the housing of the collimator.

[0187] (Item 10) The image processing device according to any one of items 1 to 9, wherein the image processing unit is configured to generate a body movement amount display image that displays the body movement amount of the subject acquired based on the focus position image in a visually identifiable manner in the focus position image.

[0188] (Item 11) an X-ray irradiation unit that irradiates X-rays; an X-ray detector that detects the X-rays irradiated by the X-ray irradiation unit; an image acquisition unit including at least one optical camera disposed near the X-ray irradiation unit; and an image processing unit that generates a focal position image, based on the optical image acquired by the image acquisition unit, which has the same field of view as an image of a subject taken from the position of the focal point of the X-ray irradiation unit, and which is an image that shows an area of ​​an X-ray irradiation range, which is the range where X-rays are irradiated by the X-ray irradiation unit, and an area outside the X-ray irradiation range.

[0189] (Item 12) The X-ray irradiation unit further includes a collimator for adjusting an irradiation range of the X-rays irradiated from the X-ray irradiation unit. The optical camera includes a first optical camera and a second optical camera provided at different positions from each other, the first optical camera and the second optical camera are provided outside a housing of the collimator so as to be located near the X-ray irradiation unit; the image acquisition unit is configured to acquire a first optical image that is the optical image captured by the first optical camera and a second optical image that is the optical image captured by the second optical camera, Item 12. The X-ray imaging device according to item 11, wherein the image processing unit is configured to generate the focal position image based on the first optical image and the second optical image taken from an oblique direction on one side and an oblique direction on the other side, based on the position of the focal point of the X-ray irradiation unit.

[0190] (Item 13) The X-ray irradiation unit further includes a collimator for adjusting an irradiation range of the X-rays irradiated from the X-ray irradiation unit. The optical camera includes a first optical camera and a second optical camera provided at different positions from each other, one of the first optical camera and the second optical camera is provided at a position conjugate with a focal point of X-rays inside a housing of the collimator, and the other of the first optical camera and the second optical camera is provided outside the housing of the collimator; Item 12. The X-ray imaging device according to item 11, wherein the image processing unit is configured to generate the focal position image based on the optical image taken from a position conjugate with the X-ray focal point and the optical image taken from outside the housing of the collimator.

[0191] (Item 14) an X-ray irradiation unit that irradiates X-rays; an X-ray detector that detects the X-rays irradiated by the X-ray irradiation unit; an image acquisition unit including at least one optical camera disposed near the X-ray irradiation unit; and an image processing unit that generates a focal position image, based on the optical image acquired by the image acquisition unit, which has the same field of view as an image of a subject taken from the position of the focal point of the X-ray irradiation unit, and which is an image that shows an area of ​​the X-ray irradiation range, which is the range where X-rays are irradiated by the X-ray irradiation unit, and an area outside the X-ray irradiation range. [Explanation of symbols]

[0192] 1,600 X-ray equipment 2, 302 Image acquisition unit 3, 201, 301, 401, 501 Image processing device 10 X-ray irradiation section 10b Collimator 10d Housing (collimator housing) 11 X-ray detector 13 Display section 20 Optical Camera 20a 1st optical camera 20b Second optical camera 30a, 230a, 330a, 430a, 501a Image processing unit 30b Image output control unit 40 Optical Images 40a First optical image 40b Second optical image 41 Focus position image 42 Body movement display image 50 Location information of the first optical camera 51 Location information of the second optical camera 52 trained models 60 Focus (X-ray focus) 63 X-ray irradiation range 90 Subjects 100, 200, 300, 400, 500 X-ray system

Claims

1. 1. An image processing device for generating an image for positioning a subject in an X-ray imaging device, comprising: an image acquisition unit including at least one optical camera disposed near an X-ray irradiation unit of the X-ray imaging device; and an image processing unit that generates a focal position image, based on the optical image captured by the optical camera, which has the same field of view as when the subject is captured from the position of the focal point of the X-ray irradiation unit, and which is an image that shows an area of ​​the X-ray irradiation range, which is the range where X-rays are irradiated by the X-ray irradiation unit, and an area outside the X-ray irradiation range.

2. At least one of the optical cameras is provided outside a housing of a collimator included in the X-ray irradiation unit, The image processing device according to claim 1 , wherein the image processing unit is configured to generate the focus position image based on the optical image captured by the optical camera provided outside the housing of the collimator.

3. The optical camera includes a first optical camera and a second optical camera provided at different positions from each other, the image acquisition unit is configured to acquire a first optical image that is the optical image captured by the first optical camera and a second optical image that is the optical image captured by the second optical camera, The image processing device according to claim 2 , wherein the image processing unit is configured to generate the focus position image based on the first optical image and the second optical image.

4. the first optical camera and the second optical camera are disposed at positions near the X-ray irradiation unit and configured to capture the first optical image and the second optical image, 4. The image processing device according to claim 3, wherein the image processing unit is configured to generate the focal position image based on the first optical image and the second optical image captured from an oblique direction on one side and an oblique direction on the other side, with the position of the focal point of the X-ray irradiation unit as a reference.

5. 5. The image processing device according to claim 4, wherein the image processing unit is configured to generate the focus position image by combining the first optical image and the second optical image based on position information of the first optical camera and position information of the second optical camera.

6. 4. The image processing device according to claim 3, wherein the image processing unit is configured to generate the focal position image based on a trained model generated by training the device to generate an image of the same field of view as when a subject is photographed from the position of the X-ray focal point from a plurality of the optical images taken from different oblique directions, the first optical image, and the second optical image.

7. an image output control unit that controls output of the focus position image to a display unit, The image processing device according to claim 3 , wherein the image output control unit is configured to perform control to switch between and output at least one of the first optical image and the second optical image together with the focus position image to the display unit.

8. the first optical camera is disposed inside the housing of the collimator and configured to capture the first optical image from a position conjugate with a focal point of X-rays, and the second optical camera is disposed at a position outside the housing of the collimator and configured to capture the second optical image; 4. The image processing device according to claim 3, wherein the image processing unit is configured to generate the focal position image based on the first optical image taken from a position conjugate with a focal point of X-rays and the second optical image taken from outside the housing of the collimator.

9. 9. The image processing device according to claim 8, wherein the image processing unit is configured to generate an image of a region of the X-ray irradiation range in the focal position image based on the optical image taken from a position conjugate with the X-ray focus, and to generate an image of a region of the focal position image outside the X-ray irradiation range based on the optical image taken from outside the housing of the collimator.

10. The image processing device according to claim 1 , wherein the image processing unit is configured to generate a body movement amount display image that displays the body movement amount of the subject acquired based on the focus position image in a visually identifiable manner in the focus position image.

11. an X-ray irradiation unit that irradiates X-rays; an X-ray detection unit that detects the X-rays irradiated by the X-ray irradiation unit; an image acquisition unit including at least one optical camera disposed near the X-ray irradiation unit; and an image processing unit that generates a focal position image, based on the optical image captured by the optical camera, which has the same field of view as when a subject is photographed from the position of the focal point of the X-ray irradiation unit, and which is an image that shows an area of ​​the X-ray irradiation range, which is the range where X-rays are irradiated by the X-ray irradiation unit, and an area outside the X-ray irradiation range.

12. a collimator for adjusting an irradiation range of the X-rays irradiated from the X-ray irradiator, The optical camera includes a first optical camera and a second optical camera provided at different positions from each other, the first optical camera and the second optical camera are provided outside a housing of the collimator so as to be located near the X-ray irradiation unit; the image acquisition unit is configured to acquire a first optical image that is the optical image captured by the first optical camera and a second optical image that is the optical image captured by the second optical camera, 12. The X-ray imaging device according to claim 11, wherein the image processing unit is configured to generate the focal point position image based on the first optical image and the second optical image captured from an oblique direction on one side and an oblique direction on the other side, with the position of the focal point of the X-ray irradiation unit as a reference.

13. a collimator for adjusting an irradiation range of the X-rays irradiated from the X-ray irradiator, The optical camera includes a first optical camera and a second optical camera provided at different positions from each other, one of the first optical camera and the second optical camera is provided at a position conjugate with a focal point of X-rays inside a housing of the collimator, and the other of the first optical camera and the second optical camera is provided outside the housing of the collimator; The X-ray imaging device according to claim 11 , wherein the image processing unit is configured to generate the focal position image based on the optical image captured from a position conjugate with the focal point of X-rays and the optical image captured from outside the housing of the collimator.

14. an X-ray irradiation unit that irradiates X-rays; an X-ray detection unit that detects the X-rays irradiated by the X-ray irradiation unit; an image acquisition unit including at least one optical camera disposed near the X-ray irradiation unit; and an image processing unit that generates a focal position image, based on the optical image captured by the optical camera, which has the same field of view as an image of the subject captured from the position of the focal point of the X-ray irradiation unit and which shows an area of ​​the X-ray irradiation range, which is the range where X-rays are irradiated by the X-ray irradiation unit, and an area outside the X-ray irradiation range.

Images