Imaging unit and imaging system

Abstract

This imaging unit comprises a first sensor module, a second sensor module, a processing board, a first connecting member, and a second connecting member. The first sensor module has a first lens and a first sensor. The second sensor module has a second lens and a second sensor. The processing board executes image processing that is based on a first image signal and a second image signal. The first connecting member is flexible and electrically connects the first sensor module and the processing board. The second connecting member is flexible and electrically connects the second sensor module and the processing board.

Description

[Technical Field]

[0001] The present disclosure relates to an imaging unit and an imaging system. [Background technology]

[0002] An example of a conventional imaging system is the imaging system described in Patent Document 1. This conventional imaging system includes a first sensor module and a second sensor module that detect scintillation light emitted from a scintillator. The first sensor module and the second sensor module capture images of the scintillation light emitted from the front and back surfaces of the scintillator, respectively. This realizes dual-energy imaging, which captures radiographic images of an object in different energy bands. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-154733 Summary of the Invention [Problem to be solved by the invention]

[0004] In the imaging system described above, since multiple sensor modules are used, the configuration of the imaging unit that constitutes the imaging system is likely to be complex. Furthermore, in the imaging system described above, there may be restrictions on the placement of the scintillator in order to optimize the imaging of the target object. In such cases, it is necessary to ensure the degree of freedom in adjusting the imaging position in the imaging unit.

[0005] An object of the present disclosure is to provide an imaging unit and an imaging system that can ensure a degree of freedom in adjusting the imaging position with a simple configuration. [Means for solving the problem]

[0006] An imaging unit according to one aspect of the present disclosure includes a first sensor module, a second sensor module, a processing board, a first connecting member, and a second connecting member. The first sensor module has a first lens that collects first scintillation light and a first sensor that detects the first scintillation light collected by the first lens and outputs a first image signal corresponding to the detection result. The second sensor module has a second lens that collects second scintillation light and a second sensor that detects the second scintillation light collected by the second lens and outputs a second image signal corresponding to the detection result. The processing board performs image processing based on the first image signal and the second image signal. The first connecting member electrically connects the first sensor module and the processing board and is flexible. The second connecting member electrically connects the second sensor module and the processing board and is flexible.

[0007] In this imaging unit, a common processing board processes the first image signal and the second image signal from the first sensor module and the second sensor module. Therefore, the configuration is simplified compared to a configuration in which a processing board is provided for each sensor module. Furthermore, in this imaging unit, in order to share the common processing board, the first connecting member and the second connecting member connecting the first sensor module and the second sensor module to the processing board are each flexible. This makes it possible to adjust the imaging positions of the first sensor module and the second sensor module separately. Therefore, sufficient freedom in adjusting the imaging positions can be ensured.

[0008] The imaging unit may further include a scintillator that emits scintillation light when radiation is incident thereon, thereby improving workability when incorporating the imaging unit into an imaging system.

[0009] The scintillator may have a first surface that serves as a radiation incidence surface and a second surface opposite to the first surface. The first sensor module may be disposed on the first surface side of the scintillator in a direction in which the first and second surfaces face each other. The first sensor module may detect scintillation light emitted from the first surface in response to incident radiation as first scintillation light. The second sensor module may be disposed on the second surface side of the scintillator in the facing direction. The second sensor module may detect scintillation light emitted from the second surface in response to incident radiation as second scintillation light. This makes it possible to preferably achieve dual energy imaging using, for example, scintillation light in a low-energy band and scintillation light in a high-energy band.

[0010] The first sensor module and the second sensor module may be disposed at a distance from the scintillator on one side of the first surface and the second surface in the in-plane direction. The distance between the first lens of the first sensor module and the first surface in the facing direction may be smaller than the distance between the second lens of the second sensor module and the second surface in the facing direction. The position of the second lens in the in-plane direction may be closer to the scintillator than the position of the first lens in the in-plane direction. In this case, when incorporating the imaging unit into a system, the first surface of the scintillator can be brought closer to the object. Furthermore, even when the first surface of the scintillator is brought closer to the object, the optical path length of the first scintillation light can be made to match the optical path length of the second scintillation light.

[0011] The scintillator may have a first surface that is a radiation incidence surface and a second surface opposite the first surface. The first sensor module and the second sensor module may be disposed on the first surface side of the scintillator in the opposing direction of the first and second surfaces and may be aligned in the in-plane direction of the first surface. The first sensor module may detect scintillation light emitted from the first surface in response to incident radiation as first scintillation light. The second sensor module may detect scintillation light emitted from the first surface in response to incident radiation as second scintillation light. In this case, the first sensor module and the second sensor module can each accurately detect scintillation light from one surface of the scintillator.

[0012] The scintillator may have a first surface that is a radiation incidence surface and a second surface opposite the first surface. The first sensor module and the second sensor module may be disposed on the second surface side of the scintillator in the opposing direction of the first and second surfaces and may be aligned in the in-plane direction of the second surface. The first sensor module may detect scintillation light emitted from the second surface in response to incident radiation as first scintillation light. The second sensor module may detect scintillation light emitted from the second surface in response to incident radiation as second scintillation light. In this case, the first sensor module and the second sensor module can each accurately detect scintillation light from one surface of the scintillator.

[0013] In the in-plane direction of the first and second surfaces, the fields of view of the first lens of the first sensor module and the second lens of the second sensor module may partially overlap. In this case, the fields of view of the first lens and the second lens are continuous, so that scintillation light can be captured over a wide range without any blind spots.

[0014] The first sensor module and the second sensor module may be disposed at a distance from the scintillator on one side of the in-plane direction of the first surface and the second surface. The distance between the first lens of the first sensor module and the scintillator in the facing direction may be equal to the distance between the second lens of the second sensor module and the scintillator in the facing direction. The positions of the first lens and the second lens relative to the scintillator in the in-plane direction may be the same. In this case, the first lens and the second lens can be a common lens. Furthermore, image correction due to the difference in the optical path length between the first scintillation light incident on the first lens and the optical path length of the second scintillation light incident on the second lens is not required, thereby avoiding complicated image processing on the processing board.

[0015] According to one aspect of the present disclosure, there is provided an imaging system including a transport device that transports an object, a radiation source that emits radiation toward the object transported by the transport device, and the imaging unit that performs image processing based on an image signal corresponding to the radiation that has passed through the object. As described above, this imaging system has a simplified configuration and can ensure sufficient freedom in adjusting the imaging position. [Effects of the Invention]

[0016] According to the present disclosure, it is possible to provide an imaging unit and an imaging system that can ensure a degree of freedom in adjusting the imaging position with a simple configuration. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of an imaging system according to the first embodiment. [Figure 2] FIG. 2 is a plan view of the imaging unit shown in FIG. [Figure 3] FIG. 3 is a diagram showing a schematic configuration of an imaging unit according to the second embodiment. [Figure 4] FIG. 4 is a plan view of the imaging unit shown in FIG. [Figure 5] FIG. 5 is a diagram showing the fields of view of the first lens and the second lens shown in FIG. [Figure 6] FIG. 6 is a diagram showing a schematic configuration of an imaging unit according to the third embodiment. [Figure 7] FIG. 7 is a plan view of the imaging unit shown in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicate explanations will be omitted. Furthermore, for the sake of convenience, each drawing is drawn with the target portion of the description emphasized. Therefore, the dimensional proportions of each component in the drawings do not necessarily correspond to the actual ones.

[0019] [First embodiment] FIG. 1 is a diagram illustrating a schematic configuration of an imaging system according to a first embodiment of the present disclosure. FIG. 2 is a plan view of the imaging unit illustrated in FIG. 1. As illustrated in FIGS. 1 and 2, the imaging system 1 according to the first embodiment is a device for acquiring a radiographic image of an object A. The imaging system 1 is an X-ray imaging system using a scintillator double-sided observation method. The imaging system 1 is applied to, for example, inline X-ray inspection. The imaging system 1 has excellent performance in discriminating materials made of light elements. The imaging system 1 is applied to, for example, fields such as food inspection and battery inspection. The object A contains, for example, a material made of light elements. In the field of food inspection, for example, the presence or absence of a foreign object trapped inside the food is inspected. Examples of such materials include food scraps, hair, plastic, insects, and bones in meat.

[0020] The imaging system 1 includes a conveying device 20 that conveys an object A in a predetermined conveying direction D (X-axis direction), a radiation source 30 that emits radiation L such as white X-rays toward the object A being conveyed by the conveying device 20, and an imaging unit 3A that performs image processing based on an image signal corresponding to the radiation L that has passed through the object A.

[0021] The conveying device 20 has, for example, a belt conveyor 21 that moves along a circular orbit. An object A is placed or held on a conveying surface 21a of the belt conveyor 21. The belt conveyor 21 is a conveying stage or a conveying unit. The conveying device 20 is equipped with a drive source (not shown) that drives the belt conveyor 21. The conveying device 20 is configured to convey the object A at a constant speed in a conveying direction D. In other words, the object A is conveyed by the conveying device 20 on a predetermined conveying path P. In this embodiment, the conveying direction D is horizontal. Furthermore, the conveying path P is linear. The direction in which the conveying path P extends is parallel to the conveying direction D. The conveying timing and conveying speed of the object A in the conveying device 20 are set in advance and controlled by a control unit.

[0022] The imaging system 1 can accommodate any type of conveying device 20. The conveying direction D and the conveying path P may be horizontal. The conveying direction D and the conveying path P may be inclined relative to the horizontal. The conveying path P does not have to be straight, but may be curved. In this case, the conveying direction D may be a tangent to the portion of the conveying path P that overlaps the radiation irradiation area. The conveying device 20 does not need to have a physical conveying surface 21a. The conveying device 20 may convey the object A in a floating state using air. The conveying device 20 may convey the object A by releasing it into the air. In this case, the conveying path P may be, for example, parabolic. The conveying device 20 may have a roller conveyor including multiple rollers.

[0023] The radiation source 30 emits radiation L. The radiation L is, for example, a cone beam X-ray. The radiation source 30 may be a microfocus X-ray source or a millifocus X-ray source. The radiation L emitted from the radiation source 30 forms a radiation flux. The area where the radiation flux exists is the emission area of the radiation source 30.

[0024] The imaging unit 3A is disposed on the opposite side of the radiation source 30 with respect to the conveying surface 21a of the belt conveyor 21. The imaging unit 3A is attached to the conveying device 20 so as not to interfere with the rotation of the belt conveyor 21. The same applies when the conveying device 20 is a roller conveyor. The imaging unit 3A is disposed with a certain gap from the conveying part such as the belt conveyor or roller conveyor so as not to interfere with the movement of the conveying part.

[0025] The imaging unit 3A includes a scintillator 4, a first mirror 51, a second mirror 52, a first sensor module 6, a second sensor module 7, a processing board (image processing unit, control unit) 8, a first connecting member 91, and a second connecting member 92.

[0026] The scintillator 4 is a wavelength conversion member. The scintillator 4 emits scintillation light when radiation L that has passed through the object A is incident on it. The scintillator 4 has a rectangular plate shape extending in the detection width direction (Y-axis direction). The scintillator 4 has a first surface 4a that is the incident surface for radiation L and a second surface 4b that faces the first surface 4a in the Z-axis direction. The first surface 4a and the second surface 4b are parallel to the conveyance surface 21a of the belt conveyor 21. The first surface 4a faces the radiation source 30. The scintillator 4 converts the radiation L that has passed through the object A into scintillation light (visible light). Relatively low-energy X-rays are converted into scintillation light S1 on the first surface 4a of the scintillator 4 and output from the first surface 4a. Relatively high-energy X-rays are converted into scintillation light S2 on the second surface 4b of the scintillator 4 and output from the second surface 4b.

[0027] The scintillator 4 may be, for example, Gd2O2S:Tb, Gd2O2S:Pr, CsI:Tl, CdWO4, CaWO4, Gd2SiO5:Ce, Lu 0.4 Gd 1.6 SiO5, Bi4Ge3O 12, Lu2SiO5:Ce, Y2SiO5, YAlO3:Ce, Y2O2S:Tb, YTaO4:Tm, YAG:Ce, YAG:Pr, YGAG:Ce, YGAG:Pr, GAGG:Ce, etc. The thickness of the scintillator 4 is set to an appropriate value in the range of several μm to several mm depending on the energy band of the radiation to be detected. The scintillator 4 may be made up of a single scintillator. The scintillator 4 may also be a combination of multiple scintillators. When multiple scintillators are combined, the types of the scintillators may be the same or different.

[0028] The first mirror 51 is a mirror made of, for example, aluminum-deposited glass or mirror-finished metal. The first mirror 51 is arranged on the radiation source 30 side with respect to the scintillator 4. The first mirror 51 has a rectangular plate shape extending in the detection width direction (Y-axis direction). The first mirror 51 has a reflecting surface 51a. The reflecting surface 51a forms an acute angle with the first surface 4a of the scintillator 4. The reflecting surface 51a faces obliquely with respect to the first surface 4a and also faces obliquely with respect to the first sensor module 6. The reflecting surface 51a reflects the scintillation light S1 emitted from the first surface 4a toward the first sensor module 6.

[0029] The second mirror 52 is a mirror made of, for example, aluminum-deposited glass or mirror-finished metal. The second mirror 52 is disposed on the opposite side of the scintillator 4 from the first mirror 51. The second mirror 52 has a rectangular plate shape extending in the detection width direction (Y-axis direction). The second mirror 52 has a reflecting surface 52a. The reflecting surface 52a forms an acute angle with the second surface 4b of the scintillator 4. The reflecting surface 52a faces obliquely with respect to the second surface 4b and also faces obliquely with respect to the second sensor module 7. The reflecting surface 52a reflects the scintillation light S2 emitted from the second surface 4b toward the second sensor module 7.

[0030] The reflecting surface 51a has an area sufficient to reflect the scintillation light S1 emitted in the normal direction of the first surface 4a. The reflecting surface 52a has an area sufficient to reflect the scintillation light S2 emitted in the normal direction of the second surface 4b. The angle between the reflecting surface 51a and the first surface 4a and the angle between the reflecting surface 52a and the second surface 4b are preferably within a range of 40 degrees or more and 50 degrees or less. In the present embodiment, these angles are 45 degrees. These angles may be determined based on the arrangement of the radiation source 30 and the position of a slit in the housing, which will be described later. The arrangements of the first sensor module 6 and the second sensor module 7 may be adjusted appropriately depending on the magnitude of these angles.

[0031] The first sensor module 6 is disposed at a distance from the scintillator 4 on one side (downstream of the scintillator 4 in the transport direction D) in the X-axis direction (in-plane direction of the first surface 4a and second surface 4b of the scintillator 4). The first sensor module 6 is disposed on the first surface 4a side of the scintillator 4 in the Z-axis direction (the opposing direction between the first surface 4a and second surface 4b of the scintillator 4). The first sensor module 6 detects, as first scintillation light, scintillation light S1 emitted from the first surface 4a in response to incidence of radiation L. Note that the first scintillation light refers to the scintillation light detected by the first sensor module.

[0032] The first sensor module 6 captures images in accordance with the movement of the object A. The first sensor module 6 is a lens-coupling type detector. Specifically, the first sensor module 6 has a first lens 61, a first body 62, and a first sensor 63. The first lens 61 is attached to the first body 62. The first lens 61 faces the reflecting surface 51a of the first mirror 51 in the X-axis direction. The optical axis of the first lens 61 is parallel to the X-axis direction. The focal point of the first lens 61 is adjusted to the reflecting surface 51a. The field of view 61a of the first lens 61 covers a wide range of the reflecting surface 51a in the Y-axis direction. The first lens 61 collects the scintillation light S1 reflected by the reflecting surface 51a. The first sensor 63 is provided in the first body 62. The first sensor 63 detects the scintillation light S1 collected by the first lens 61 and outputs a first image signal corresponding to the detection result.

[0033] The first sensor 63 is an image sensor. The first sensor 63 is, for example, a general line sensor, a multi-line sensor, or an area image sensor capable of TDI (time delay integration) drive. The first sensor 63 is, for example, a CCD area image sensor or a CMOS image sensor. The first sensor 63 has an element array in which multiple light-receiving elements are aligned in a pixel direction. The image pitches of the multiple light-receiving elements may be the same or different. In the first sensor 63, multiple element arrays are aligned in an integral direction corresponding to the movement direction of the object A. The first sensor 63 has a scan direction corresponding to the transport direction D of the object A and a line direction perpendicular to the scan direction. This scan direction is the above-mentioned integral direction and is parallel to the Z-axis direction. The line direction is the above-mentioned pixel direction and is parallel to the Y-axis direction. The scan direction is a direction converted from the transport direction D via the first mirror 51. In this embodiment, the scan direction is converted by 90 degrees from the transport direction D.

[0034] The first sensor 63 is controlled by the control unit to transfer charges in synchronization with the movement of the object A. That is, the first sensor 63 transfers charges on the light-receiving surface in synchronization with the movement of the object A by the transport device 20. This makes it possible to obtain a radiographic image with a good S / N ratio. If the first sensor 63 is an area image sensor, the control unit may be configured to control the radiation source 30 and the first sensor module 6 to turn on the radiation source 30 in synchronization with the imaging timing of the first sensor module 6. The first sensor module 6 may be controlled by a signal from an encoder provided on the stage.

[0035] The second sensor module 7 is disposed on one side in the X-axis direction and spaced apart from the scintillator 4. The second sensor module 7 is disposed on the second surface 4b side of the scintillator 4 in the Z-axis direction. The second sensor module 7 detects, as second scintillation light, scintillation light S2 emitted from the second surface 4b in response to incidence of radiation L. The second scintillation light refers to the scintillation light detected by the second sensor module.

[0036] The second sensor module 7 captures images in accordance with the movement of the object A. The second sensor module 7 is a lens-coupling type detector. Specifically, the second sensor module 7 has a second lens 71, a second body 72, and a second sensor 73. The second lens 71 is attached to the second body 72. The second lens 71 faces the reflecting surface 52a of the second mirror 52 in the X-axis direction. The optical axis of the second lens 71 is parallel to the X-axis direction. The focal point of the second lens 71 is adjusted to the reflecting surface 52a. The field of view 71a of the second lens 71 covers a wide range of the reflecting surface 52a in the Y-axis direction. The second lens 71 collects the scintillation light S2 reflected by the reflecting surface 52a. The second sensor 73 is provided within the second body 72. The second sensor 73 detects the scintillation light S2 collected by the second lens 71 and outputs a second image signal corresponding to the detection result. The second sensor 73 has the same configuration as the first sensor 63, and is controlled in the same manner as the first sensor 63. A detailed description of the second sensor 73 will be omitted.

[0037] The processing board 8 has a board 81 and a processor (not shown) attached to the board 81. The processing board 8 functions as an image processing unit that executes image processing based on the first image signal output from the first sensor 63 and the second image signal output from the second sensor 73. Specifically, the processing board 8 performs image processing such as magnification correction, luminance value correction, dark correction, shading correction, affine transformation processing, edge enhancement processing, noise removal processing, bilateral filtering processing, or angle of view adjustment on at least one of the first image signal and the second image signal. The processing board 8 outputs the radiographic image created by executing the image processing to a computer.

[0038] The processing board 8 also functions as a control unit that controls the imaging conditions of the first sensor 63 and the second sensor 73. Specifically, the processing board 8 sets the exposure time, gain, imaging frequency, imaging timing, etc. for the first sensor 63 and the second sensor 73. The processing board 8 also functions as an image processing unit or control unit, adjusting the imaging timing of the first sensor 63, the imaging timing of the second sensor 73, and the image processing timing. This facilitates processing such as matching the detection ranges of the first image signal and the second image signal, and comparing or combining the first image signal and the second image signal. The processing board 8 may also control the output of at least one of the first image signal and the second image signal to be delayed by a period exceeding the exposure time.

[0039] Here, one processing board 8 is provided for the first sensor module 6 and the second sensor module 7. That is, the processing board 8 is shared by the first sensor module 6 and the second sensor module 7.

[0040] The first connection member 91 electrically connects the first sensor module 6 and the processing board 8. Specifically, the first connection member 91 electrically connects the first sensor 63 and the image processor via wiring provided in the first body 62 and wiring provided on the board 81. The second connection member 92 electrically connects the second sensor module 7 and the processing board 8. Specifically, the second connection member 92 electrically connects the second sensor 73 and the image processor via wiring provided in the second body 72 and wiring provided on the board 81. This makes it possible to output the first image signal and the second image signal to the processing board 8.

[0041] Each of the first connecting member 91 and the second connecting member 92 is flexible. Each of the first connecting member 91 and the second connecting member 92 is easily deformable when subjected to a load equivalent to the force of an operator's finger, for example. Each of the first connecting member 91 and the second connecting member 92 is formed, for example, by a cable and a connector. Each of the first connecting member 91 and the second connecting member 92 is formed, for example, by a harness and a connector. Each of the first connecting member 91 and the second connecting member 92 is, for example, a flexible connector.

[0042] The imaging unit 3A has a housing (not shown) having, for example, a rectangular parallelepiped shape. The scintillator 4, the first mirror 51, the second mirror 52, the first sensor module 6, the second sensor module 7, and the processing board 8 are housed in the housing. The scintillator 4, the first mirror 51, the second mirror 52, the first sensor module 6, the second sensor module 7, and the processing board 8 are each held by the housing. A slit is formed in a wall of the housing on the radiation source 30 side to allow radiation L emitted from the radiation source 30 to pass through. The slit has, for example, a rectangular shape extending in the detection width direction (Y-axis direction).

[0043] The housing is made of a material that can block X-rays, for example. The housing is a so-called dark box. The housing may be made of metal, for example. The housing is made of aluminum, iron, stainless steel, or the like. The housing may include a protective material. The protective material is, for example, metal. Examples of the protective material include lead, tungsten, copper, iron, stainless steel, etc. The housing has a shape that is elongated in the transport direction D. The housing may be attached to the transport device 20.

[0044] The imaging system 1 includes a control unit (not shown). The control unit controls the radiation source 30 based on values of the tube voltage and tube current of the radiation source 30 stored by user input or the like. The control unit controls each of the first sensor module 6 and the second sensor module 7 based on the exposure times and the like of the first sensor module 6 and the second sensor module 7 stored by user input or the like. The control unit and the image processing processor of the processing board 8 may be separate processors or may be the same processor.

[0045] Next, the positional relationship between the scintillator 4, the first mirror 51, the second mirror 52, the first sensor module 6, and the second sensor module 7 will be described.

[0046] The distance in the Z-axis direction between the reflecting surface 51a and the first surface 4a of the scintillator 4 is smaller than the distance in the Z-axis direction between the reflecting surface 52a and the second surface 4b of the scintillator 4. In other words, the optical path length in the Z-axis direction of the scintillation light S1 between the reflecting surface 51a and the first surface 4a is smaller than the optical path length in the Z-axis direction of the scintillation light S2 between the reflecting surface 52a and the second surface 4b.

[0047] The distance in the Z-axis direction between the first lens 61 and the first surface 4a of the scintillator 4 is smaller than the distance in the Z-axis direction between the second lens 71 and the second surface 4b of the scintillator 4. Specifically, the distance between the optical axis of the first lens 61 and the first surface 4a is smaller than the distance between the optical axis of the second lens 71 and the second surface 4b. The position of the second lens 71 in the X-axis direction is closer to the scintillator 4 than the position of the first lens 61 in the X-axis direction. In other words, the optical path length in the X-axis direction of the scintillation light S2 between the reflecting surface 52a and the second lens 71 is smaller than the optical path length in the X-axis direction of the scintillation light S1 between the reflecting surface 51a and the first lens 61.

[0048] The optical path length of scintillation light S1 between the first surface 4a of the scintillator 4 and the first lens 61 is equal to the optical path length of scintillation light S2 between the second surface 4b of the scintillator 4 and the second lens 71. Specifically, the sum of the optical path length of scintillation light S1 in the Z-axis direction between the reflecting surface 51a and the first surface 4a and the optical path length of scintillation light S1 in the X-axis direction between the reflecting surface 51a and the first lens 61 is equal to the sum of the optical path length of scintillation light S2 in the Z-axis direction between the reflecting surface 52a and the second surface 4b and the optical path length of scintillation light S2 in the X-axis direction between the reflecting surface 52a and the second lens 71.

[0049] In this way, in the imaging unit 3, the first mirror 51 and the first sensor module 6 are brought close to the scintillator 4 in the Z-axis direction, and the optical path lengths of the scintillation light S1 and S2 are made to match. This allows the scintillator 4 to be brought close to the object A, and a radiological image of the object A can be acquired with high accuracy.

[0050] As described above, the first connecting member 91 and the second connecting member 92 are each flexible. That is, the first sensor module 6 and the second sensor module 7 are connected to the processing board 8 by the first connecting member 91 and the second connecting member 92, while their positions relative to the processing board 8 are adjustable. This makes it possible to easily adjust the positional relationship as described above by adjusting the positions of the first sensor module 6 and the second sensor module 7.

[0051] Next, the operation of the imaging system 1, that is, the method of acquiring a radiological image, will be described.

[0052] First, the object A is conveyed in the conveying direction D by the conveying device 20. Furthermore, the radiation source 30 emits radiation L toward the object A. The radiation L that has passed through the object A is incident on the first surface 4a. Next, the radiation L is converted into scintillation light by the scintillator 4. The scintillation light S1 emitted from the first surface 4a is reflected by the first mirror 51 and formed into an image on the first sensor 63 by the first lens 61 of the first sensor module 6. The first sensor 63 captures the scintillation light S1 (scintillation image) formed by the first lens 61.

[0053] In this imaging process, charge transfer (TDI operation if the first sensor 63 is an area image sensor) is performed in synchronization with the movement of the object A. The first sensor module 6 outputs radiation image data (first image signal) obtained by imaging to the processing board 8. The second sensor module 7, like the first sensor module 6, images the scintillation light S2 and outputs the obtained radiation image data (second image signal) to the processing board 8. The processing board 8 receives the radiation image data and performs predetermined processing such as image processing on the received radiation image data to create a radiation image. The processing board 8 outputs the created radiation image to a computer. The computer displays the radiation image output from the processing board 8. In this manner, radiation images obtained by observing both sides of the object A are obtained.

[0054] As described above, in the imaging unit 3A, the processing board 8 that processes the first image signal and the second image signal from the first sensor module 6 and the second sensor module 7 is shared. Therefore, the configuration is simplified compared to a configuration in which a processing board is provided for each sensor module. Furthermore, in the imaging unit 3A, in order to share the processing board 8, the first connecting member 91 and the second connecting member 92 that connect the first sensor module 6 and the second sensor module 7 to the processing board 8 are each flexible. Therefore, it is possible to adjust the imaging positions of the first sensor module 6 and the second sensor module 7 separately, ensuring sufficient freedom in adjusting the imaging positions.

[0055] The imaging unit 3A includes a scintillator 4 that emits scintillation light S1, S2 in response to incidence of radiation L. This allows for improved workability when incorporating the imaging unit 3A into the imaging system 1.

[0056] The scintillator 4 has a first surface 4a that serves as an incident surface for radiation L, and a second surface 4b that faces the first surface 4a. The first sensor module 6 is disposed on the first surface 4a side of the scintillator 4 in the Z-axis direction. The first sensor module 6 detects scintillation light S1 emitted from the first surface 4a in response to incidence of radiation L as first scintillation light. The second sensor module 7 is disposed on the second surface 4b side of the scintillator 4 in the Z-axis direction. The second sensor module 7 detects scintillation light S2 emitted from the second surface 4b in response to incidence of radiation L as second scintillation light. This makes it possible to preferably achieve dual-energy imaging using, for example, scintillation light in a low-energy band and scintillation light in a high-energy band.

[0057] The first sensor module 6 and the second sensor module 7 are disposed at a distance from the scintillator 4 on one side in the X-axis direction. The distance between the first lens 61 and the first surface 4a of the first sensor module 6 in the Z-axis direction is smaller than the distance between the second lens 71 and the second surface 4b of the second sensor module 7 in the Z-axis direction. The position of the second lens 71 in the X-axis direction is closer to the scintillator 4 than the position of the first lens 61 in the Z-axis direction. This allows the first surface 4a of the scintillator 4 to be brought closer to the object A when incorporating the imaging unit 3A into the imaging system 1. Furthermore, even when the first surface 4a of the scintillator 4 is brought closer to the object A, the optical path length of the scintillation light S1 (first scintillation light) and the optical path length of the scintillation light S2 (second scintillation light) can be made to match.

[0058] As described above, the imaging system 1 simplifies the configuration and ensures sufficient freedom in adjusting the imaging position.

[0059] [Second embodiment] Fig. 3 is a diagram showing a schematic configuration of an imaging unit according to a second embodiment of the present disclosure. Fig. 4 is a plan view of the imaging unit shown in Fig. 3. As shown in Figs. 3 and 4, the imaging unit 3B according to the second embodiment differs from the imaging unit 3A of the first embodiment in that the first sensor module 6 and the second sensor module 7 are arranged on the first surface 4a side of the scintillator 4 and are aligned in the Y-axis direction, and in that the imaging unit 3B does not include a second mirror 52.

[0060] The imaging system according to the second embodiment is a scintillator surface observation type X-ray imaging system. In the imaging unit 3B, the first sensor module 6 and the second sensor module 7 are arranged on the first surface 4a side of the scintillator 4 in the Z-axis direction and are aligned in the Y-axis direction (in-plane direction of the first surface 4a). The first sensor module 6 detects scintillation light S1 emitted from the first surface 4a in response to incidence of radiation L as first scintillation light. The second sensor module 7 detects scintillation light S1 emitted from the first surface 4a in response to incidence of radiation L as second scintillation light.

[0061] The distance in the Z-axis direction between the first lens 61 and the scintillator 4 of the first sensor module 6 is equal to the distance in the Z-axis direction between the second lens 71 and the scintillator 4 of the second sensor module 7. Specifically, the distance between the optical axis of the first lens 61 and the first surface 4a is equal to the distance between the optical axis of the second lens 71 and the first surface 4a. In other words, the optical path length in the Z-axis direction of the scintillation light S1 (scintillation light S1 incident on the first lens 61) between the reflecting surface 51a of the first mirror 51 and the first surface 4a is equal to the optical path length in the Z-axis direction of the scintillation light S1 (scintillation light S1 incident on the second lens 71) between the reflecting surface 51a and the first surface 4a.

[0062] The positions of the first lens 61 and the second lens 71 in the X-axis direction with respect to the scintillator 4 are the same. That is, the optical path length of the scintillation light S1 in the X-axis direction between the reflecting surface 51a and the first lens 61 is equal to the optical path length of the scintillation light S1 in the X-axis direction between the reflecting surface 51a and the second lens 71. In this way, the optical path length of the scintillation light S1 between the first surface 4a of the scintillator 4 and the first lens 61 is equal to the optical path length of the scintillation light S1 between the first surface 4a of the scintillator 4 and the second lens 71.

[0063] FIG. 5 is a diagram showing the fields of view of the first lens 61 and the second lens 71 shown in FIG. 3. The first mirror 51 is not shown in FIG. 5. As shown in FIG. 5, the fields of view of the first lens 61 and the second lens 71 partially overlap in the Y-axis direction. Specifically, as viewed in the Z-axis direction, the range of the field of view 61a of the first lens 61 in the Y-axis direction relative to the first surface 4a partially overlaps with the range of the field of view 61a of the second lens 71 in the Y-axis direction relative to the first surface 4a. As viewed in the Z-axis direction, on the reflecting surface 51a of the first mirror 51 (see FIG. 3), the range of the field of view 61a of the first lens 61 in the Y-axis direction partially overlaps with the range of the field of view 71a of the second lens 71 in the Y-axis direction. An overlap region R exists between the fields of view 61a and 71a. The width of the overlap region R in the Y-axis direction can be adjusted by adjusting the positions of the first sensor module 6 and the second sensor module 7 in the Y-axis direction.

[0064] In this way, in the imaging unit 3B, the first sensor module 6 and the second sensor module 7 are aligned in the Y-axis direction, thereby widening the field of view of the imaging unit 3B in the Y-axis direction, and by appropriately providing an overlapping region R, the field of view 61a and the field of view 71a are made continuous in the Y-axis direction.

[0065] As described above, the first connecting member 91 and the second connecting member 92 are flexible, and therefore the positions of the first sensor module 6 and the second sensor module 7 relative to the processing board 8 can be adjusted. This makes it possible to easily adjust the positional relationship as described above by adjusting the positions of the first sensor module 6 and the second sensor module 7.

[0066] As described above, the scintillator 4 has a first surface 4a that serves as an incident surface for radiation L, and a second surface 4b that faces the first surface 4a. The first sensor module 6 and the second sensor module 7 are disposed on the first surface 4a side of the scintillator 4 in the Z-axis direction and are aligned in the Y-axis direction. The first sensor module 6 detects, as first scintillation light, scintillation light S1 that is emitted from the first surface 4a in response to incidence of radiation L. The second sensor module 7 detects, as second scintillation light, scintillation light S1 that is emitted from the first surface 4a in response to incidence of radiation L. This allows the first sensor module 6 and the second sensor module 7 to accurately detect the scintillation light S1 from one surface of the scintillator 4.

[0067] In the Z-axis direction, the fields of view 61a, 71a of the first lens 61 of the first sensor module 6 and the second lens 71 of the second sensor module 7 partially overlap each other. This makes the fields of view 61a of the first lens 61 and the fields of view 71a of the second lens 71 continuous, allowing the scintillation light S1 to be captured over a wide range without any blind spots.

[0068] The first sensor module 6 and the second sensor module 7 are disposed at a distance from the scintillator 4 on one side in the X-axis direction. The distance between the first lens 61 of the first sensor module 6 and the scintillator 4 in the Z-axis direction is equal to the distance between the second lens 71 of the second sensor module 7 and the scintillator 4 in the Z-axis direction. The positions of the first lens 61 and the second lens 71 relative to the scintillator 4 in the X-axis direction are the same. This allows the first lens 61 and the second lens 71 to be shared. Furthermore, image correction caused by the difference in the optical path length between the scintillation light S1 (first scintillation light) incident on the first lens 61 and the optical path length of the scintillation light S1 (second scintillation light) incident on the second lens 71 is not required, thereby avoiding complicated image processing on the processing board 8.

[0069] [Third embodiment] Fig. 6 is a diagram showing a schematic configuration of an imaging unit according to a third embodiment of the present disclosure. Fig. 7 is a plan view of the imaging unit shown in Fig. 6. As shown in Figs. 6 and 7, an imaging unit 3C according to the third embodiment differs from the imaging unit 3B of the second embodiment in that the first sensor module 6 and the second sensor module 7 are arranged on the second surface 4b side of the scintillator 4, and in that the imaging unit 3C does not include a first mirror 51 but includes a second mirror 52.

[0070] The imaging system according to the third embodiment is a scintillator backside observation type X-ray imaging system. In the imaging unit 3C, a first sensor module 6 and a second sensor module 7 are arranged on the second surface 4b side of the scintillator 4 in the Z-axis direction. The first sensor module 6 detects scintillation light S2 emitted from the second surface 4b in response to incidence of radiation L as first scintillation light. The second sensor module 7 detects scintillation light S2 emitted from the second surface 4b in response to incidence of radiation L as second scintillation light.

[0071] In the imaging unit 3C, similar to the imaging unit 3B according to the second embodiment, the distance between the optical axis of the first lens 61 and the second surface 4b is equal to the distance between the optical axis of the second lens 71 and the second surface 4b, and the positions of the first lens 61 and the second lens 71 in the X-axis direction are consistent with each other relative to the scintillator 4. Also, in the imaging unit 3C, similar to the imaging unit 3B according to the second embodiment, the fields of view of the first lens 61 and the second lens 71 partially overlap in the Y-axis direction.

[0072] As described above, the scintillator 4 has a first surface 4a that serves as an incident surface for radiation L, and a second surface 4b that faces the first surface 4a. The first sensor module 6 and the second sensor module 7 are disposed on the second surface 4b side of the scintillator 4 in the Z-axis direction and are aligned in the Y-axis direction. The first sensor module 6 detects, as first scintillation light, scintillation light S2 that is emitted from the second surface 4b in response to incidence of radiation L. The second sensor module 7 detects, as second scintillation light, scintillation light S2 that is emitted from the second surface 4b in response to incidence of radiation L. This allows the first sensor module 6 and the second sensor module 7 to accurately detect the scintillation light S2 from one surface of the scintillator 4.

[0073] [Variations] The present disclosure is not limited to the above-described embodiment. For example, although the imaging units 3A, 3B, and 3C include the scintillator 4, the imaging units 3A, 3B, and 3C may not include the scintillator 4. The scintillator 4 may not be included in the imaging units 3A, 3B, and 3C. The scintillator 4 may be included in the imaging system. [Explanation of symbols]

[0074] 1...imaging system, 3A, 3B, 3C...imaging unit, 4...scintillator, 4a...first surface, 4b...second surface, 6...first sensor module, 7...second sensor module, 8...processing board, 20...transport device, 30...radiation source, 61...first lens, 61a, 71a...field of view, 63...first sensor, 71...second lens, 73...second sensor, 91...first connecting member, 92...second connecting member, A...object, L...radiation, S1, S2...scintillation light.

Claims

1. a first sensor module including a first lens that collects first scintillation light and a first sensor that detects the first scintillation light collected by the first lens and outputs a first image signal corresponding to the detection result; a second sensor module including a second lens that collects the second scintillation light and a second sensor that detects the second scintillation light collected by the second lens and outputs a second image signal corresponding to the detection result; a processing board that performs image processing based on the first image signal and the second image signal; a flexible first connection member that electrically connects the first sensor module and the processing board; a second flexible connection member that electrically connects the second sensor module and the processing board; a scintillator that emits scintillation light in response to incidence of radiation, the scintillator has a first surface that serves as an incident surface for the radiation and a second surface opposite to the first surface, the first sensor module is disposed on the first surface side of the scintillator in a direction in which the first surface and the second surface oppose each other, and detects the scintillation light emitted from the first surface in response to the incidence of the radiation as the first scintillation light; The second sensor module is an imaging unit arranged on the second surface side of the scintillator in the opposing direction, and detects the scintillation light emitted from the second surface in response to the incidence of the radiation as the second scintillation light.

2. The first sensor module and the second sensor module are arranged at a distance from the scintillator on one side of the first surface and the second surface in an in-plane direction, a distance between the first lens and the first surface of the first sensor module in the facing direction is smaller than a distance between the second lens and the second surface of the second sensor module in the facing direction; The imaging unit according to claim 1 , wherein a position of the second lens in the in-plane direction is closer to the scintillator than a position of the first lens in the in-plane direction.

3. a first sensor module including a first lens that collects first scintillation light and a first sensor that detects the first scintillation light collected by the first lens and outputs a first image signal corresponding to the detection result; a second sensor module including a second lens that collects the second scintillation light and a second sensor that detects the second scintillation light collected by the second lens and outputs a second image signal corresponding to the detection result; a processing board that performs image processing based on the first image signal and the second image signal; a first flexible connection member that electrically connects the first sensor module and the processing board; a second flexible connection member that electrically connects the second sensor module and the processing board; a scintillator that emits scintillation light in response to incidence of radiation, the scintillator has a first surface that serves as an incident surface for the radiation and a second surface opposite to the first surface, the first sensor module and the second sensor module are disposed on the first surface side of the scintillator in a direction in which the first surface and the second surface oppose each other, and are aligned in an in-plane direction of the first surface, the first sensor module detects the scintillation light emitted from the first surface in response to the incidence of the radiation as the first scintillation light; The second sensor module detects the scintillation light emitted from the first surface in response to the incidence of the radiation as the second scintillation light.

4. An imaging unit as described in Claim 3, wherein a portion of the field of view of the first lens of the first sensor module and the second lens of the second sensor module overlaps in the in-plane direction of the first surface and the second surface.

5. The first sensor module and the second sensor module are arranged at a distance from the scintillator on one side of the first surface and the second surface in an in-plane direction, a distance between the first lens and the scintillator of the first sensor module in the facing direction is equal to a distance between the second lens and the scintillator of the second sensor module in the facing direction, The imaging unit according to claim 3 , wherein the first lens and the second lens are positioned in the in-plane direction with respect to the scintillator.

6. a first sensor module including a first lens that collects first scintillation light and a first sensor that detects the first scintillation light collected by the first lens and outputs a first image signal corresponding to the detection result; a second sensor module including a second lens that collects the second scintillation light and a second sensor that detects the second scintillation light collected by the second lens and outputs a second image signal corresponding to the detection result; a processing board that performs image processing based on the first image signal and the second image signal; a flexible first connection member that electrically connects the first sensor module and the processing board; a second flexible connection member that electrically connects the second sensor module and the processing board; a scintillator that emits scintillation light in response to incidence of radiation, the scintillator has a first surface that serves as an incident surface for the radiation and a second surface opposite to the first surface, the first sensor module and the second sensor module are disposed on the second surface side of the scintillator in a direction in which the first surface and the second surface oppose each other, and are aligned in an in-plane direction of the second surface, the first sensor module detects the scintillation light emitted from the second surface in response to the incidence of the radiation as the first scintillation light; The second sensor module detects the scintillation light emitted from the second surface in response to the incidence of the radiation as the second scintillation light.

7. An imaging unit as described in Claim 6, wherein a portion of the field of view of the first lens of the first sensor module and the second lens of the second sensor module overlaps in the in-plane direction of the first surface and the second surface.

8. The first sensor module and the second sensor module are arranged at a distance from the scintillator on one side of the first surface and the second surface in an in-plane direction, a distance between the first lens and the scintillator of the first sensor module in the facing direction is equal to a distance between the second lens and the scintillator of the second sensor module in the facing direction, The imaging unit according to claim 6 , wherein the first lens and the second lens are positioned in the in-plane direction with respect to the scintillator.

9. a conveying device that conveys an object; a radiation source that emits radiation toward the object transported by the transport device; an imaging unit that performs image processing based on an image signal corresponding to the radiation that has passed through the object, The imaging unit a first sensor module including a first lens that collects first scintillation light and a first sensor that detects the first scintillation light collected by the first lens and outputs a first image signal corresponding to the detection result; a second sensor module including a second lens that collects the second scintillation light and a second sensor that detects the second scintillation light collected by the second lens and outputs a second image signal corresponding to the detection result; a processing board that performs image processing based on the first image signal and the second image signal; a flexible first connection member that electrically connects the first sensor module and the processing board; a second flexible connection member electrically connecting the second sensor module and the processing board.

10. The imaging system described in Claim 9, wherein the imaging unit further comprises a scintillator that emits scintillation light when the radiation is incident thereon.

11. The scintillator has a first surface that is an incident surface of the radiation and a second surface opposite to the first surface, the first sensor module is disposed on the first surface side of the scintillator in a direction in which the first surface and the second surface oppose each other, and detects the scintillation light emitted from the first surface in response to the incidence of the radiation as the first scintillation light; The imaging system of claim 10 , wherein the second sensor module is disposed on the second surface side of the scintillator in the opposing direction, and detects the scintillation light emitted from the second surface in response to the incidence of the radiation as the second scintillation light.

12. The first sensor module and the second sensor module are arranged at a distance from the scintillator on one side of the first surface and the second surface in an in-plane direction, a distance between the first lens and the first surface of the first sensor module in the facing direction is smaller than a distance between the second lens and the second surface of the second sensor module in the facing direction; The imaging system according to claim 11 , wherein a position of the second lens in the in-plane direction is closer to the scintillator than a position of the first lens in the in-plane direction.

13. The scintillator has a first surface that is an incident surface of the radiation and a second surface opposite to the first surface, the first sensor module and the second sensor module are disposed on the first surface side of the scintillator in a direction in which the first surface and the second surface oppose each other, and are aligned in an in-plane direction of the first surface, the first sensor module detects the scintillation light emitted from the first surface in response to the incidence of the radiation as the first scintillation light; The imaging system according to claim 10 , wherein the second sensor module detects the scintillation light emitted from the first surface in response to the incidence of the radiation as the second scintillation light.

14. The scintillator has a first surface that is an incident surface of the radiation and a second surface opposite to the first surface, the first sensor module and the second sensor module are disposed on the second surface side of the scintillator in a direction in which the first surface and the second surface oppose each other, and are aligned in an in-plane direction of the second surface, the first sensor module detects the scintillation light emitted from the second surface in response to the incidence of the radiation as the first scintillation light; The imaging system according to claim 10 , wherein the second sensor module detects the scintillation light emitted from the second surface in response to the incidence of the radiation as the second scintillation light.

15. An imaging system as described in claim 13 or 14, wherein in the in-plane direction of the first surface and the second surface, a portion of the field of view of the first lens of the first sensor module and the second lens of the second sensor module overlaps.

16. The first sensor module and the second sensor module are arranged at a distance from the scintillator on one side of the first surface and the second surface in an in-plane direction, a distance between the first lens and the scintillator of the first sensor module in the facing direction is equal to a distance between the second lens and the scintillator of the second sensor module in the facing direction, 16. The imaging system according to claim 13, wherein the first lens and the second lens are positioned in the in-plane direction relative to the scintillator.

Images