Dual-arm robot control system for non-destructive evaluation

Abstract

A system for nondestructive evaluation of an object controls two robotic arms using a spherical coordinate system. In some examples, the system includes a radiation source coupled to one of the robotic arms, a radiation detector coupled to the other robotic arm, and a control unit. The control unit is configured to: determine, based on an input, a first position located on a first surface of a first sphere in the spherical coordinate system; determine, based on the input, a second position located on a second surface of a second sphere in the spherical coordinate system, the second position being opposite the first position with respect to a midpoint of the spherical coordinate system; and control motion of the radiation source robotic arm and the detector robotic arm such that the radiation source and the radiation detector move to different ones of the first and second positions.

Description

Technical Field

[0001] [Data of Related Applications] This application claims priority to U.S. Patent Application No. 16 / 885,115, filed on May 27, 2020, entitled "DUAL ROBOT CONTROL SYSTEMS FOR NON-DESTRUCTIVE EVALUATION", which is hereby incorporated by reference in its entirety.

[0002] The present disclosure relates to non-destructive evaluation of objects.

Background Art

[0003] X-ray digital radiography (DR) is a commonly used non-invasive and non-destructive imaging technique that uses a digital X-ray detector such as a flat panel detector, a charge-coupled device (CCD) camera, a complementary metal-oxide-semiconductor (CMOS) camera, or a linear diode array (LDA). X-ray computed tomography (CT) is a procedure for creating a 3D image of an object using computer-processed X-ray radiographs acquired at different viewing angles. A tomographic image of an object is an image of a conceptually two-dimensional "slice" of the object. A computing device can use the tomographic images of the object to generate a three-dimensional image of the object. X-ray CT can be used for industrial applications to perform non-destructive evaluation of objects.

Summary of the Invention

[0004] Generally, the present disclosure relates to non-destructive evaluation (NDE) such as industrial X-ray radiography, computed tomography (CT), and metrology. The present disclosure describes apparatuses and methods that can simplify the alignment of radiation sources and detectors for a user while enabling non-destructive evaluation of an object from many different viewpoints. The techniques of the present disclosure provide instrumentation design, user control mechanisms, and software algorithms for the apparatus. The apparatus can be used for NDE of naturally occurring objects such as rock core samples, and can also be used for NDE of manufactured parts and systems such as metal castings, engine components, and complete engine units. The apparatus can comprise a radiation source, a radiation detector, and a sample manipulator, each associated with a motion control system. The sample manipulator can position the sample so that radiographs can be obtained at different positions and field angles.

[0005] In one example, the present disclosure is a system for non-destructive evaluation of an object, comprising a first robotic arm, a radiation source coupled to the first robotic arm and configured to emit radiation, a second robotic arm, a radiation detector coupled to the second robotic arm and configured to measure radiation emitted by the radiation source, a stage configured to support the object for non-destructive evaluation, and a control unit, wherein the control unit is configured to determine, based on an input, a first position located on a first surface of a first sphere within a spherical coordinate system, and to determine, based on the input, a second position located on a second surface of a second sphere within the spherical coordinate system, wherein the second position is located opposite the first position with respect to the center of the spherical coordinate system, and to control the motion of the first robotic arm and the second robotic arm such that the radiation source and the radiation detector move to different ones of the first position and the second position.

[0006] In another example, the present disclosure is a non-transitory computer-readable data storage medium storing instructions that, when executed by a system for non-destructive evaluation of an object placed on a stage, cause the system to determine, based on an input, a first position located on a first surface of a first sphere in a spherical coordinate system, and to determine, based on the input, a second position located on a second surface of a second sphere in the spherical coordinate system, wherein the second position is located opposite the first position with respect to the center of the spherical coordinate system, and to control the movement of a first robotic arm and the movement of a second robotic arm such that a radiation source and a radiation detector move to different positions among the first position and the second position.

[0007] In another example, the present disclosure describes a method including determining, based on an input to a system for non-destructive evaluation of an object placed on a stage, a first position located on a first surface of a first sphere in a spherical coordinate system, and determining, based on the input, a second position located on a second surface of a second sphere in the spherical coordinate system, wherein the second position is located opposite the first position with respect to the center of the spherical coordinate system, and controlling the movement of a first robotic arm and the movement of a second robotic arm such that a radiation source and a radiation detector move to different positions among the first position and the second position.

[0008] Details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description, drawings, and claims.

Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0017] Non-destructive evaluation (NDE) or non-destructive analysis (NDA) of an object may involve non-invasively imaging, measuring, or otherwise evaluating a two-dimensional or three-dimensional structure. Among the techniques commonly used for NDE in medical or industrial imaging are X-ray radiography and computed tomography (CT). One or more of the exemplary techniques of the present disclosure relate to industrial applications of X-ray CT or metrology. For example, FIG. 1 is a schematic diagram showing an overhead view of an exemplary equipment setup according to one or more of the techniques of the present disclosure. As shown in the example of FIG. 1, an NDE system 10, such as an industrial CT system, can include a radiation source 12 and a radiation detector 14. The radiation source 12 can emit electromagnetic radiation such as an X-ray beam 16. Therefore, in some instances, the present disclosure may refer to the radiation source 12 or a similar device as an "X-ray generator". In some examples, the X-ray beam 16 may be conical. In other examples, the X-ray beam 16 may be fan-shaped. In some examples, the X-ray source 12 generates X-rays having an energy range of 20 keV to 600 keV. In other examples, the X-ray source 12 may generate X-rays in other energy ranges. In other examples, the beam 16 may include other frequencies of the electromagnetic spectrum, such as a gamma-ray beam.

[0018] The sample can be placed on the manipulator. In system 10, the manipulator can include a rotary stage 18 (i.e., a rotating stage) having a rotation axis 20. The rotary stage 18 can be configured to hold and rotate a sample or object 22 and can be disposed between an X-ray source 12 (i.e., an X-ray generator) and a radiation detector 14. As a result, by rotating the sample within the X-ray beam 16, radiographs can be acquired at different projection angles or viewpoints. Thus, in some examples where the manipulator includes a rotating stage 18, the computing system of system 10 can acquire radiographs at different rotation angles at different detector positions and can process the radiographs to assemble the radiographs into a three-dimensional radiograph of the sample. In some examples, the rotary stage 18 can include an 18-inch nickel-plated aluminum turntable platter.

[0019] As shown in the example of FIG. 1, the radiation detector 14 may include a flat panel X-ray detector (FPD). In other examples, the radiation detector 14 may include a lens-coupled scintillation detector, a linear diode array (LDA), or another type of radiation detector. The FPD can include a scintillation material, for example, a layer of cesium iodide fabricated on amorphous silicon on a glass detector array. The scintillator layer absorbs X-rays and emits visible light photons, which are then detected by a solid-state detector. The detector pixel size can range from several tens of micrometers to several hundreds of micrometers. In some examples where the radiation detector 14 includes a flat panel X-ray detector, the pixel size of the radiation detector 14 can range from 25 micrometers to 250 micrometers. In some examples, the pixel size of the radiation detector 14 can range from approximately 25 micrometers to approximately 250 micrometers. Further, the field of view of a typical commercial FPD can range from approximately 100 mm to 500 mm. Commercial FPDs can be used in applications that require a wide field of view.

[0020] In high-resolution applications, an optical lens may be used to relay the emitted visible light to a detector, such as a charge-coupled device (CCD) or complementary metal-oxide-semiconductor (CMOS) detector, in a lens-coupled detector. In some examples, the lens may provide a magnification in the range of 1× to 100×, so that the effective pixel size is from 0.1 micrometer to 20 micrometers. In some examples where the radiation detector 14 includes a lens-coupled detector, the pixel size of the radiation detector 14 is within the range of 0.1 micrometer to 10 micrometers. Further, in some examples where the radiation detector 14 includes a lens-coupled detector, the field of view can range from 0.2 mm to 25 mm.

[0021] The user of system 10 may be interested in capturing images (e.g., X-ray images) of parts, samples, or objects 22 from multiple different angles in order to thoroughly evaluate their internal structure. Some conventional imaging systems may include components configured to operate either or both of the radiation source 12 and / or the detector 14 generally along a linear axis. For example, a conventional imaging system may include rails, gears, and / or other mechanical components configured to linearly translate the radiation source 12 and / or the detector 14 along orthogonal Cartesian axes, such as a horizontal axis (e.g., towards and away from the object 22) and / or a vertical axis. In these examples, the user may need to manually reorient the object 22 with respect to the radiation source 12 and the detector 14 in order to image the object 22 from different rotational angles. This can be difficult or inconvenient when the object 22 is relatively large, bulky, and / or heavy. Thus, some other conventional imaging systems include a “C-arm” system, where each of the radiation source 12 and the detector 14 is attached to opposite ends of a machine shaped like the letter “C”. In some examples, the C-shaped machine then rotates around the object 22 to image the object from multiple angles. A typical example of this type of C-arm system is a dentist's X-ray machine, which rotates around the patient's head to image the patient's teeth from multiple viewpoints. In other examples, the object to be evaluated may be placed on a rotary stage, which can rotate the object with respect to the radiation source and the detector. However, since both the radiation source 12 and the detector 14 are rigidly coupled to the same structure, a typical C-arm system is similarly limited in mobility in that the stage and / or the C-arm can only rotate around a single vertical or horizontal axis, e.g., the C-arm system can only image the object 22 along an axis that is directly orthogonal (e.g., perpendicular) to the axis of rotation of the C-arm structure.

[0022] A more advanced imaging system, for example, the NDE system 10 shown in FIG. 1, can include two robotic arms 24, 26. The radiation source 12 and the detector 14 are attached to the distal ends of different robotic arms among the robotic arms 24, 26. The robotic arms 24, 26 can then be operated independently of each other to image the object 22 from multiple angles along multiple different axes of rotation. Each of the robotic arms 24, 26 can include one or more joints 30A-30F (collectively, "joint 30") that define a plurality of degrees of freedom within the three-dimensional space for imaging the object 22. For example, each robotic arm can include six joints. However, these additional degrees of freedom provide both advantages and disadvantages. The imaging of the object 22 can be improved by the robotic arms 24, 26, but the dual-arm robotic arms 24, 26 of a system such as the system 10 can impose additional (e.g., excessive) complexity on the imaging process. For example, to successfully image or measure the object 22, the radiation source 12 and the detector 14 must be aligned directly opposite each other with respect to the object 22. Since each robotic arm 24, 26 can be manually operated (e.g., via a graphical user interface, a variable-speed omnidirectional joystick, or other user input device) independently of the other robotic arm, some dual-arm robotic arm type systems may require significant trial and error and / or manual positioning to properly align the radiation source 12, the object 22, and the radiation detector 14.

[0023] In some examples according to the present disclosure, the NDE system 10 includes a control unit such as the image acquisition system 28. The control unit is configured to receive an input indicating at least a desired imaging angle (e.g., imaging viewpoint) and a desired imaging magnification, and automatically align the radiation source 12, the object 22, and the detector 14 based on the user input. For example, the image acquisition system 28 can determine the radiation source position and the detector position based on the desired imaging angle and / or the desired imaging magnification, and then control the joints of the robotic arms to place the radiation source and the detector in their respective positions.

[0024] The image acquisition system 28 can include a computing system. Exemplary types of computing systems can include personal computers, server computers, mainframe computers, laptop computers, dedicated computers, and the like. The image acquisition system 28 can perform computer-controlled image acquisition procedures, which include determining the radiation source position and the detector position based on an input and then controlling (e.g., consisting of) any of a plurality of controllable mechanical components of the system 10 to move the radiation source 12 towards the radiation source position and the radiation detector 14 towards the detector position (e.g., rotate and / or translate). In some examples according to the present disclosure, the image acquisition system 28 can determine (e.g., generate or calculate) the radiation source position and the detector position according to positions defined by a spherical coordinate system, the radiation source position being located at a point on the surface of a first virtual sphere 32 and the detector position being located at a point on the surface of a second virtual sphere 34, the two virtual spheres being concentric, e.g., sharing a common center 33 with the spherical coordinate system.

[0025] FIG. 2 is a conceptual block diagram showing some exemplary components of the system 10 of FIG. 1 according to the techniques of the present disclosure. In the example of FIG. 2, the system 10 includes a housing 11, a radiation source 12, a radiation detector 14, a rotary stage 18, a first robotic arm 24, a second robotic arm 26, an image acquisition system 28, orientation units 46 and 48, and a pressure sensor 50. In other examples, the system 10 may include more components, fewer components, or different components.

[0026] In some examples, one or more components of system 10 are housed within housing 11. Housing 11 can have a radiation shield, such as a protective shield, that resists radiation energy at a fixed potential of up to 240 kilovolts (kV). In some examples, the enclosure can have dimensions of approximately 158 inches wide × approximately 98 inches deep × approximately 123 inches high (e.g., approximately 401 cm wide × approximately 249 cm deep × approximately 312 cm high). Housing 11 can be composed of lead and / or steel components and can define a motorized sliding access door for accessing rotary stage 18 and positioning object 22 for non-destructive evaluation (e.g., imaging or gauging). Housing 11 can further include an internal light, a cabled access port with a cover, and an “X-ray on” warning light.

[0027] Image acquisition system 28 is configured to receive an input indicating at least a desired imaging angle and a desired imaging magnification and then, based on the input, automatically align radiation source 12, object 22, and detector 14. For example, the received input can include a direct (e.g., real-time) user input, or in some examples, can include a set of predetermined instructions stored within a file that image acquisition system 28 imports or otherwise receives.

[0028] Image acquisition system 28 can include a computing system. For example, image acquisition system 28 can perform computer-controlled image acquisition procedures that include determining a radiation source position and a detector position based on the received input and then controlling any of a plurality of controllable mechanical components of system 10 to move (e.g., rotate and / or translate) radiation source 12 toward the determined radiation source position and radiation detector 14 toward the determined detector position. Image acquisition system 28 can determine (e.g., receive, generate, or calculate) a radiation source position and a detector position within a spherical coordinate system, where the radiation source position is located at a point on the surface of a first virtual sphere and the detector position is located at a point on the surface of a second virtual sphere, and the two virtual spheres are concentric.

[0029] As shown in FIG. 2, the image acquisition system 28 can include at least a processing circuit unit 36, a memory 38, and a user interface 40. The processing circuit unit 36 is configured to execute an alignment unit 42 and an imaging unit 44. The alignment unit 42 is configured to receive a user input indicating a desired imaging viewpoint (e.g., imaging angle) and / or a desired imaging magnification via a user interface (UI) 40. The user interface 40 can include any suitable user input / output device, such as a graphical user interface, an interactive voice interface, a command line interface, etc. Based on the user input, the alignment unit 42 can determine the radiation source position and the detector position to align the radiation source 12 and the radiation detector 14 on opposite sides of the center of the spherical coordinate system centered on the center 33. In the example shown in FIGS. 1 and 3, the center 33 is located at a predetermined distance above the rotary stage 18, for example, along the rotation axis 20 (FIG. 1). However, as will be described in more detail below, the image acquisition system 28 can move the center 33 to any position (e.g., redefine the position of the center 33) based on the received input.

[0030] Additionally or alternatively, the alignment unit 42 can determine the radiation source orientation and / or the detector orientation based on the received input. For example, the alignment unit 42 can direct the radiation source 12 and / or the radiation detector 14 so that the radiation source 12 and / or the radiation detector 14 are "aimed" at each other from their respective positions, e.g., so that the radiation beam 16 is directed from the radiation source position 12 to the detector 14, by controlling the radiation source orientation unit 46 and / or the detector orientation unit 48. For example, the radiation source orientation unit 46 can be an example of one of the joints 30 of the robotic arm 24 (e.g., joint 30C of FIG. 1), configured to rotate to change the orientation of the radiation source 12, e.g., a ball-and-socket type joint. Similarly, the detector orientation unit 48 can be an example of one of the joints 30 of the robotic arm 26 (e.g., joint 30F of FIG. 1), configured to rotate to change the orientation of the radiation detector 14, e.g., a ball-and-socket type joint. In other examples, each of the radiation source orientation unit 46 and the detector orientation unit 48 can include two or more joints 30 configured to cooperate or act in concert (e.g., under the control of the alignment unit 42) to mimic the functionality of a single ball-and-socket type joint.

[0031] When the alignment unit 42 aligns and / or orients both the radiation source 12 and the radiation detector 14, the imaging unit 44 can non-destructively evaluate (e.g., irradiate and image or measure) the object 22 disposed on the rotary stage 18 by causing the radiation source 12 to emit a radiation beam 16 that passes through the object 22 and contacts the surface of the radiation detector 14.

[0032] In some examples, the radiation detector 14 comprises a protective plate having at least one pressure sensor 50. The protective plate is configured such that the pressure sensor 50 disables the movement of the robotic arm 26 in response to detecting contact with another article, such as the object 22, the inner surface of the housing 11, the radiation source 12, or the robotic arm 24. For example, for some relatively large or irregularly shaped objects 22, movement of the robotic arm 26 can cause the radiation detector 14 to contact a portion of the object 22. In these examples, the pressure sensor 50 detects physical contact with the object 22 and immediately terminates further movement of the robotic arm 26 to the image acquisition system 28, thereby reducing or preventing damage to the object 22. The pressure sensor 50 can comprise a sensing plate that is highly transmissive to the radiation beam 16 and can trigger the stopping of the robotic arm 26 with a reaction time on the order of milliseconds.

[0033] Figures 3-6 are conceptual diagrams of various exemplary coordinate systems, and an NDE system (e.g., the alignment unit 42 of the image acquisition system 28 of the NDE system 10 of FIG. 2) can use these coordinate systems to calculate or determine at least the radiation source position 52 of the radiation source 12 and the detector position 54 of the radiation detector 14. For example, FIG. 3 shows a conceptual side view of an exemplary spherical coordinate system 60 centered about a center 33.

[0034] The radiation source 12 is located at a radiation source position 52 that is a point within the space defined by the spherical coordinate system 60. For example, the alignment unit 42 can define a first virtual sphere 32 that is located within the spherical coordinate system 60 and centered, for example, about the center 33 of the coordinate system 60. The alignment unit 42 can then determine (e.g., calculate and / or assign) the radiation source position 52 to be a point located on the surface of the first virtual sphere 32. For example, the radiation source position 52 can be defined by three spherical coordinates, such as a radius R, an elevation angle θ, and an azimuth angle φ (shown in FIG. 4). As shown in FIG. 3, the radiation source position 52 has an elevation angle θ above a horizontal plane 56 that passes through the center 33 of the coordinate system 60 Sis located at. The radiation source position 52 is located at a distance measured by a radiation source radius R from the center 33 S and the radiation source radius R S defines the radius of the first virtual sphere 32.

[0035] Similarly, the radiation detector 14 is located at a detector position 54 at a point within the space defined by the spherical coordinate system 60. For example, the alignment unit 42 can define a second virtual sphere 34 centered on the center 33 of the coordinate system 60, which is located within the spherical coordinate system 60. The alignment unit 42 can then determine (e.g., calculate and / or assign) the detector position 54 to be located at a point on the surface of the second virtual sphere 34. For example, the detector position 54 can be defined by three spherical coordinates, namely, the radius R, the elevation angle θ, and the azimuth angle φ (shown in FIG. 4). As shown in FIG. 3, the detector position 54 is located below the horizontal plane 56 at an elevation angle θ D . Here, the detector elevation angle θ D is equal to and opposite the radiation source elevation angle θ S . The detector position 54 is located at a distance measured by a detector radius R from the center 33, and the detector radius R D defines the radius of the second virtual sphere 34. D

[0036] In some examples, the alignment unit 42 is configured to receive additional user input indicating a desired image magnification for imaging an object 22 disposed on the stage 18, e.g., via the user interface 40. The alignment unit 42 determines the values of the radiation source radius R S and the detector radius R D based on the desired image magnification. Here, the magnification M is equal to the sum of the detector radius and the radiation source radius divided by the radiation source radius, e.g., given by the following equation: M = (R D + R s ) / R s

[0037] ​Once the alignment unit 42 determines the radiation source position 52 and the detector position 54, the alignment unit 42 controls the robotic arms 24, 26 to move the radiation source 12 to the radiation source position 52 and the radiation detector 14 to the detector position 54. In some examples, the robotic arm 24 can be configured to move the radiation source 12 from the current radiation source position to the intended radiation source position 52 according to a defined virtual sphere 32. For example, the robotic arm 24 can first move the radiation source 12 radially inward or outward from the current radiation source radius to the intended radiation source radius R S and then rotate the robotic arm 24 (e.g., via the joint 30) so that the radiation source 12 moves along the surface of the virtual sphere 32 toward the intended radiation source position 52. Similarly, the robotic arm 26 can be configured to move the radiation detector 14 from the current detector position to the intended detector position 54 according to a defined virtual sphere 34. For example, the robotic arm 26 can first move the radiation detector 14 radially inward or outward from the current detector radius to the intended detector radius R D and then rotate the robotic arm 26 (e.g., via the joint 30) so that the radiation detector 14 moves along the surface of the virtual sphere 34 toward the intended detector position 54.

[0038] In another example, rather than controlling the radiation source radius and the radiation source angle separately, the alignment unit 42 can define a series of intermediate waypoints between the current radiation source position and the desired radiation source position. The set of waypoints can approximate a curve or an arc between the current radiation source position and the desired radiation source position, such that each subsequent waypoint defines a gradual change in both the radius and the angle from the center 33. The alignment unit 42 can then control the joint 30 of the robotic arm 24 so that the radiation source 12 reaches the intended radiation source position following the arc defined by the waypoints.

[0039] Similarly, the alignment unit 42 can define a series of intermediate waypoints between the current detector position and the desired detector position. The set of waypoints can approximate a curve or arc between the current detector position and the desired detector position, such that each subsequent waypoint defines a gradual change in both the radius and angle from the center 33. The alignment unit 42 can then control the joints 30 of the robotic arm 26 such that the radiation detector 24 reaches the intended detector position along the arc defined by the waypoints.

[0040] FIG. 4 is a perspective view of the exemplary spherical coordinate system 60 of FIG. 3. The radiation source 12 can be described by a radiation source elevation angle θ S in addition to a radiation source azimuth angle φ “above” the horizontal axis 58 along the horizontal plane 56. S Accordingly, the radiation source position 52 can be described by three spherical coordinates (R S , θ S , φ S ). The image acquisition system 28 is configured to determine these values of the radiation source position 52 based on user input and to control the first robotic arm 24 to move the radiation source 12 to the radiation source position 52.

[0041] Similarly, the radiation detector 14 can be described by a detector elevation angle θ D in addition to a detector azimuth angle φ “below” the horizontal axis 58 along the horizontal plane 56. D Here, the detector azimuth angle φ D of the detector position 54 is equal to and opposite the radiation source azimuth angle φ S of the radiation source position 52. Accordingly, the detector position 54 can be described by three spherical coordinates (R D , θ D , φ D ). The image acquisition system 28 is configured to determine these three values of the detector position 54 based on user input and to control the second robotic arm 26 to move the radiation detector 14 to the detector position 54.

[0042] In some examples, the image acquisition system 28 determines and / or controls the radiation source orientation vector O of the radiation source 12 S and / or the detector orientation vector O of the radiation detector 14 D For example, the image acquisition system 28 can control the radiation source orientation unit 46 (e.g., hinge 30C, or a combination of two or more hinges 30) of the robotic arm 24 to rotate the radiation source 12 while the radiation source 12 is located at the radiation source position 52. As shown in FIG. 4, when the image acquisition system 28 controls the movement of the radiation source orientation unit 46, the radiation source orientation vector O S sweeps out a radiation cone 62 that describes the possible paths along which the radiation beam 16 (FIG. 1) can be emitted from the radiation source 12. The radiation cone 62 can itself be described by two spherical coordinates within another virtual sphere centered within the orientation unit 46, e.g., the radiation source orientation azimuth angle and the radiation source orientation elevation angle. In some examples, as will be further described below with respect to FIG. 6, the radiation source 12 and the radiation detector 14 can be configured to rotate about an axis or vector connecting the two. In these examples, the radiation cone 62 can be described by a third coordinate or variable that defines the rotation about the self-axis of the cone. Control of this third rotation variable can help enable “flat field correction” of the radiation beam 16 with respect to the radiation detector 14, such as when the radiation beam 16 does not essentially generate a rotationally symmetric distribution of radiation with respect to the detector 14

[0043] Similarly, the image acquisition system 28 can control the detector orientation unit 48 (e.g., hinge 30F) of the robotic arm 26 to rotate the radiation detector 14 while the radiation detector 14 is located at the detector position 54. As shown in FIG. 4, when the image acquisition system 28 controls the movement of the orientation unit 48, the detector orientation vector O D is the possible orientation of the plane defined by the surface of the radiation detector 14, or the orientation vector O in the tangential direction with respect to the detector plane DSweeps out a detector orientation cone 64 that describes possible orientations. The detector orientation cone 64 can itself be described by two spherical coordinates within another virtual sphere centered within the orientation unit 48, for example, a detector orientation azimuth angle and a detector orientation elevation angle. In some examples, as will be further described with respect to FIG. 6, the radiation source 12 and the radiation detector 14 can be configured to rotate about an axis or vector connecting the two. In these examples, the radiation cone 64 can be described by a third coordinate or variable that defines a rotation about the self-axis of the cone. Control over this third rotation variable can serve to enable “flat field correction” of the radiation beam 16 with respect to the radiation detector 14, such as when the radiation beam 16 does not essentially produce a rotationally symmetric distribution of radiation with respect to the detector 14.

[0044] Generally, as shown in FIG. 4, system 60 defines at least 10 degrees of freedom, i.e., three position axes and two orientation axes for each of radiation source 12 and radiation detector 14. As described above, imaging 60 can define two additional variables for rotation of radiation source 12 and detector 14 about an axis connecting the two. These 12 degrees of freedom enable precise control over imaging of object 22 from virtually any desired viewpoint and magnification. However, these 12 degrees of freedom are not intended to be limiting. Other configurations of imaging 60 may define fewer degrees of freedom, additional degrees of freedom, and / or different degrees of freedom, e.g., translational axes and / or rotational axes defined by mechanical components of system 60. For example, FIG. 5 is a conceptual perspective view of another coordinate system 70, and an NDE system (e.g., the alignment unit 42 of the image acquisition system 28 of the NDE system 10 of FIG. 2) can use this coordinate system to calculate or determine at least the radiation source position 52 of radiation source 12 and the detector position 54 of radiation detector 14. Coordinate system 70 may be an example of the spherical coordinate system 60 of FIGS. 3 and 4, or the spherical coordinate system 60 may be included within coordinate system 70. For example, similar to the spherical coordinate system 60 of FIGS. 3 and 4, as shown in FIG. 5, coordinate system 70 includes a spherical coordinate system that defines virtual spheres 32, 34, and on virtual spheres 32, 34, radiation source position 52 and detector position 54 are located respectively. However, coordinate system 70 can have at least eight additional degrees of freedom not shown in FIGS. 3 and 4.

[0045] For example, the coordinate system 70 defines a Cartesian coordinate system having an x-axis 67, a y-axis 68, and a z-axis 69 that define the position of a reference point such as the center 33 of the spherical coordinate system 70. That is, the robotic arms 24 and 26 are movable horizontally and vertically together (e.g., as a cooperating unit) along the reference point x-axis, y-axis, and z-axis so as to move the radiation source 12 and the detector 14 relative to the rotary stage 18. In the example shown in FIG. 5, the center 33 of the spherical coordinate system (e.g., the spherical point (0, 0, 0)) is initially at the same position as the origin 66 of the Cartesian coordinate system (e.g., the Cartesian point (0, 0, 0)). However, the joints 30 of the robotic arms 24, 26 are configured to cooperate to mimic Cartesian (e.g., orthogonal) motion that moves the robotic arms 24 and 26 horizontally and / or vertically relative to the rotary stage 18. In other examples, the system 10 can include dedicated mechanical components such as guide rails configured to move the robotic arms 24 and 26 exclusively horizontally and / or vertically relative to the rotary stage 18.

[0046] In some examples, the coordinate system 70 defines a secondary Cartesian coordinate system centered on the detector position 54. For example, either or both of the robotic arm 26 and the radiation detector 14 can include mechanical components configured to allow the radiation detector 14 to move horizontally and / or vertically parallel along a plane defined by the surface of the radiation detector 14. For example, as shown in FIG. 5, the distal end of the robotic arm 26 can include a ball screw nut servo motor that allows the radiation detector 14 to move horizontally along the horizontal detector axis D x and / or vertically along the vertical detector axis D y This allows the detector 14 to move horizontally and / or vertically parallel along a plane that is tangential to the surface of the sphere 34, providing at least two advantages.

[0047] First, by translating the detector 14, the image acquisition system 28 can acquire a series of radiographs at different detector positions 54 along a plane defined by the surface of the detector 14 (e.g., a plane tangential to the surface of the sphere 34), where the different detector positions are separated by a distance finer than the pixel size of the radiation detector 14. The image acquisition system 28 can then assemble the radiographs, as detailed in U.S. Patent No. 9,459,217 by the same applicant, to form a composite radiograph with a higher resolution than the acquired radiographs.

[0048] Second, by translating the detector 14, the image acquisition system 28 can acquire a series of radiographs at different detector positions 54 along a plane defined by the surface of the detector 14 (e.g., a plane tangential to the surface of the sphere 34). By acquiring radiographs at two or more different detector positions that are separated from each other by an interval that is larger than the pixel size of the radiation detector 14 (e.g., much larger) but smaller than the detector size, the radiation detector 14 can cover an area larger than the physical size of the radiation detector 14. The image acquisition system 28 can then numerically "stitch" these digital radiographs together to form a composite radiograph having a field of view larger than the field of view defined by the physical size of the detector 14. Further, by acquiring radiographs when the radiation detector 14 is at two or more positions that are separated by an interval smaller than the pixel size, a sub-pixel size sampling effect can be achieved. This technique can be used to generate a composite radiograph with a higher resolution in a particular optical configuration and using a particular type of sample. Using these two techniques in combination during practice can significantly increase either or both of the imaging field of view and the resolution. Further, using these two techniques in combination with both conventional volumetric CT techniques and spiral CT techniques can increase the reconstructed three-dimensional (3D) volume and resolution of the object 22.

[0049] As shown in FIGS. 5 and 6, in some examples, system 70 can further have a set of orthogonal x-rotation axis 75, y-rotation axis 77, and z-rotation axis 76. For example, in addition to being horizontally and vertically translatable along the reference point Cartesian x-axis 67, y-axis 68, and z-axis 69, image acquisition system 28 can be configured to rotate both radiation source 12 and detector 14 together around these axes on robot arms 24 and 26. For example, as shown in FIG. 6, with an "X-axis rotation" input command, alignment system 28 can rotate both robot arms 24 and 26 around x-rotation axis 75. Similarly, with a "Y-axis rotation" input command, alignment system 28 can rotate both robot arms 24 and 26 around y-rotation axis 77. Similarly, as shown in FIG. 6, with a "Z-axis rotation" input command, alignment system 28 can also rotate either or both of radiation source 12 and / or detector 14 around z-rotation axis 76, or can rotate radiation source 12 around vector 72 (FIG. 6) connecting it to detector 14.

[0050] FIG. 5 shows two additional degrees of freedom introduced by system 10, specifically by the mechanical characteristics of rotary stage 18. As described above, rotary stage 18 can be configured to rotate around rotary axis 20. As shown in FIG. 5, rotary stage 18 can also be vertically translatable along rotary axis 20. As detailed in U.S. Patent No. 9,459,217, filed on April 2, 2014, by the same applicant, by simultaneously rotating rotary stage 18 around axis 20 and vertically translating rotary stage 18 along axis 20, image acquisition system 28 can generate a helical-type evaluation image of object 22 disposed on stage 18.

[0051] As shown in FIG. 5, the rotary stage 18 can include a first set of worm screw and rail configured to horizontally translate the rotary stage 18 in response to a "Rotary Table Left / Right" command. Similarly, the rotary stage 18 can include a second set of worm screw and rail configured to horizontally translate (e.g., forward or backward) the rotary stage 18 in response to a "Rotary Table Expand" command, thereby adjusting the relative distance between the radiation source 12, the object, and the radiation detector 14 to adjust the image magnification of the object placed on the stage. Similarly, the image acquisition system 28 can be configured to move (e.g., rotate and / or translate) any mechanical components of the system 10 around or along any of the above-described axes while the imaging unit 44 captures an image of the object 22 (e.g., causing the radiation source 12 to emit radiation towards the radiation detector 14 and irradiating the object 22).

[0052] FIG. 6 is a side view of another exemplary system 80 and can be an example of the system 10 of FIGS. 1 and 2, the system 60 of FIGS. 3 and 4, and / or the system 70 of FIG. 5. When a user of the system 80 starts a new object imaging session, the robotic arms 24, 26 (FIG. 1) may initially be in any position and / or orientation. Thus, the system 80 (e.g., the image acquisition system 28 of FIG. 2) can be configured to perform an initial alignment operation upon startup of the system 80. For example, during the alignment operation, the system 80 can control the orientation units 46, 48 (FIG. 2) to rotate (e.g., reorient) the radiation source 12 and / or the detector 14 to face each other while maintaining their spatial (e.g., x-y-z) positions. An exemplary alignment operation will be described, but other operations may be used to align the radiation source 12 and the detector 14.

[0053] System 80 can receive user input including a "midpoint of sphere" value 94A defined by the user, for example, via the GUI 90A shown in FIG. 7A. The midpoint of sphere value can include a number from 0 to 1 indicating the desired position of a reference point 66 (e.g., center of rotation) along the radiation source-detector vector 72 when the system 80 performs alignment. The user can specify the value of the midpoint of sphere value 94A and then activate the "Robot Alignment" input button 92 to cause the system 80 to perform alignment. In some examples, the system 80 can then calculate the ratio of the current distance between the radiation source 12 and the detector 14 using the midpoint of sphere value 94A. The system 80 can store this ratio as the variable "Radiation Source Z": Radiation Source Z = length (radiation source-detector) × midpoint

[0054] The system 80 can then project this distance onto the X-Z plane 78, thereby effectively removing the y component: Focus XZ = length (radiation source xz-detector xz) × midpoint

[0055] The system 80 can then use the midpoint of sphere 94A to determine the position of the reference point 66 between the radiation source 12 and the detector 14: ref = radiation source + midpoint × (detector - radiation source)

[0056] The system 80 can then calculate the initial x-axis rotation and initial y-axis rotation in spherical mode using these two distances and the reference point 66: yRot = sin -1 ref.x - radiation source x / Focus XC xRot = sin -1 ref.y - radiation source y / Radiation Source Z

[0057] The system 80 can then determine the detector Z as the remaining distance between the radiation source 12 and the detector 14: Detector Z = length (radiation source-detector) - Radiation Source Z

[0058] System 80 can then set the values of the Z-axis rotation (zRot), the detector x-axis offset (Detector X), and the detector y-axis offset (Detector Y) to zero. System 80 can then send these values to their respective axes within the spherical coordinate system.

[0059] When System 80 has completed aligning the radiation source 12 and the detector 14, System 80 can then determine the radiation source position and the detector position according to the spherical coordinate system as shown in FIGS. 3-5. For example, when any spherical movement (e.g., rotation) of the arms 24, 26 is performed, System 80 converts the current spherical axis values as shown in the GUI 90A of FIG. 7A to linear coordinates (e.g., the radiation source position and orientation and the detector position and orientation) as shown in the GUI 90B of FIG. 7B, and System 80 can then use this linear coordinate to move the robotic arms 24, 26.

[0060] In some examples, the direction of the "y" rotation axis 77 can be considered "global" because it is not affected by rotations within the system. On the other hand, in some examples, the "x" rotation axis 75 and the "z" rotation axis 76 can be considered "local" in that their directions change according to the amount of "y-axis" rotation. For example, when the y-axis 77 is rotated by 45 degrees, the direction of the x rotation axis 75 is adjusted by 45 degrees, but even if the x-axis 75 is rotated by 45 degrees, the direction of the y-axis 77 cannot change.

[0061] In some examples, System 80 can calculate the detector normal ("detNorm") vector 74 from the spherical x-axis rotation and the y-axis rotation. Similarly, the unit Z is the unit vector 76 (0, 0, 1) in the z direction. xRot, yRot, and zRot are values defined by the user from their respective spherical axes: detNorm = rotate(rotate(unit Z, xRot), yRot)

[0062] The detector horizontal position vector ("detHoriz") and the detector vertical position vector ("detVert") are calculated similarly using all the rotation axes: detHoriz = Rotate(unitX, xRot, yRot, zRot) detVert = Rotate(unitY, xRot, yRot, zRot)

[0063] System 80 can use these vectors to calculate the 3D linear position of detector 14 as an offset from the spherical reference point 66. detZ, detX, and detY are values defined by the user from their respective spherical axes: detPos = ref + detZ × detNorm + detX × detHoriz + detY × detVert

[0064] Since detector 14 and radiation source 12 are aligned with detector normal vector 74, system 80 can perform a simplified calculation using detector normal vector 74 to determine the position of radiation source 12: Radiation source Pos = ref - radiation source Z × detNorm

[0065] System 80 calculates the linear x-axis rotation of detector 14 and radiation source 12 from the projection of detector normal vector 74: Linear XRot = tan -1 detNorm.y / length(detNorm.xz)

[0066] System 80 can then pass the invariant spherical y-axis rotation and invariant spherical z-axis rotation across the linear rotations of both detector 14 and radiation source 12.

[0067] Another example of system 80 may include a graphical user interface different from that shown in FIGS. 7A and 7B (e.g., having a greater number of components, a smaller number of components, or different components). For example, in the case of a “simplified” exemplary user interface, it can be made possible for a user to input the respective three-dimensional position vectors and orientation vectors of the radiation source 12 and the radiation detector 14. The three-dimensional position vectors and orientation vectors can be received in Cartesian (x, y, z) notation or spherical (R, θ, φ) notation. In the case of a more complex exemplary user interface, it can also be made possible for a user to control each joint 30 (FIG. 1) of the robotic arms 24, 26, and it can also be made possible to enable similar dynamics that allow for more precise control of the joints 30.

[0068] In some examples, the user interface of system 80 can include a graphical representation of system 80 based on the received input. For example, the user interface can display a three-dimensional representation of the positions and orientations of the radiation source 12, the radiation detector 14, the radiation beam 16, the object 22, the stage 18, and the center 33 relative to each other. The user interface can provide a user input mechanism that enables the user to rotate the viewing perspective of the graphical representation. In some examples, system 80 can be configured to display a physical representation of the virtual center 33 of the spherical coordinate system. For example, system 80 may include a laser or LED configured to illuminate a position within the housing 11 (FIG. 2) directly above or below the center 33 of the corresponding spherical coordinate system. In other examples, system 80 may include a mechanical indicator of the center 33 configured to move within the housing 11 when system 80 moves the virtual center 33 (e.g., moves the radiation source 12 and the detector 14 together relative to the rest of system 80).

[0069] FIG. 8 is a flowchart showing an exemplary operation of a non-destructive evaluation system such as an industrial CT system or a measurement system according to one or more techniques of the present disclosure. Referring to the exemplary system 10 of FIGS. 1 and 2, the exemplary operation of FIG. 8 will be described. However, the exemplary operation of FIG. 8 is not so limited.

[0070] In the example of FIG. 8, an image acquisition system 28 (e.g., a computing device of system 10) receives (800) an input indicating a desired imaging viewpoint and / or a desired imaging magnification for X-ray imaging of an object 22 that can be placed on a rotary stage 18 of system 10. The input can include direct (e.g., real-time) user input, and in some examples, can include a set of predetermined instructions stored in a file that the image acquisition system 28 imports or otherwise receives.

[0071] Based on the received input, the image acquisition system 28 determines (e.g., generates, selects, calculates, and / or assigns) a radiation source position 52 of the radiation source 12 and a detector position 54 of the radiation detector 14. In some examples, the image acquisition system 28 may first determine the radiation source position 52 and then determine the detector position 54 (e.g., on the opposite side of the radiation source position 52) based on the radiation source position 52. In other examples, the image acquisition system 28 may first determine the detector position 54 and then determine the radiation source position 52 (e.g., on the opposite side of the detector position 54) based on the detector position 54. In other examples, the image acquisition system 28 may independently determine the radiation source position 52 and the detector position 54 based on the received input.

[0072] In some examples, the image acquisition system 28 can determine (802) a first position (e.g., the radiation source position 52) located on the surface of a first virtual sphere located within a spherical coordinate system based on an input. Similarly, the image acquisition system 28 can determine (804) a second position (e.g., the detector position 54) located on the surface of a second virtual sphere located within the same spherical coordinate system. The second position is located opposite the first position with respect to the center of the spherical coordinate system. Each of the radiation source position 52 and the detector position 54 can be described by three spherical coordinates (R, θ, φ) with respect to the center 33 of the spherical coordinate system. In some examples, the image acquisition system 28 can further determine and control the radiation source orientation 62 and the detector orientation 64 to direct the radiation beam 16 from the radiation source 12 towards the surface of the radiation detector 14.

[0073] When the image acquisition system 28 determines the first position on the surface of the first virtual sphere and the second position on the surface of the second virtual sphere, the image acquisition system 28 (e.g., the alignment unit 42 of the image acquisition system 28) controls the robotic arms 24 and 26 to move the radiation source 12 and the radiation detector 14 to different positions among the first position and the second position (806).

[0074] When the radiation source 12 and the radiation detector 14 reach their respective positions, the image acquisition system 28 (e.g., the imaging unit 44 of the image acquisition system 28) can image the object 22, for example, by causing the radiation source 12 to emit (e.g., irradiate) a radiation beam 16 that passes through the object 22 and strikes the radiation detector 14.

[0075] The following paragraphs provide additional exemplary techniques of the present disclosure.

[0076] Example 1: In some examples, a system for non-destructive evaluation of an object includes a first robotic arm, a radiation source coupled to the first robotic arm and configured to emit radiation, a second robotic arm, a radiation detector coupled to the second robotic arm and configured to measure the radiation emitted by the radiation source, a stage configured to support the object for non-destructive evaluation, and a control unit. The control unit is configured to determine a first position located on a first surface of a first sphere in a spherical coordinate system based on an input, and to determine a second position located on a second surface of a second sphere in the spherical coordinate system based on the input, where the second position is located opposite to the first position with respect to the center of the spherical coordinate system, and to control the movement of the first robotic arm and the second robotic arm such that the radiation source and the radiation detector move to different positions among the first position and the second position.

[0077] Example 2: In some examples of the system of Example 1, the control unit is further configured to receive an input indicating an imaging angle for evaluation of the object, and to determine the first position and the second position based on the imaging angle.

[0078] Example 3: In some examples of the system of Example 1 or Example 2, the control unit is further configured to control the radiation source orientation of the radiation source such that the radiation is directed from the first position or the second position towards the detector, and to control the detector orientation of the detector such that the detector is directed from the first position or the second position towards the radiation source.

[0079] Example 4: In some examples of the system of any one of Examples 1 to 3, the control unit is configured to receive an input indicating a magnification for evaluation of the object, to determine a radiation source position defining a radiation source radius based on the magnification, and to determine a detector position defining a detector radius based on the magnification, where the sum of the detector radius and the radiation source radius divided by the radiation source radius is equal to the magnification, and the radiation source position and the detector position are different positions among the first position and the second position.

[0080] Example 5: In some examples of any one of the systems of Examples 1 to 4, the control unit is further configured to cause the radiation source to irradiate an object in response to controlling the movement of the first robotic arm and the second robotic arm.

[0081] Example 6: In some examples of any one of the systems of Examples 1 to 5, the radiation detector includes a protective plate having at least one pressure sensor, and the protective plate is configured to disable the movement of the second robotic arm in response to the pressure sensor detecting contact with an article.

[0082] Example 7: In some examples of any one of the systems of Examples 1 to 6, the control unit is to obtain a series of radiographs at different detector positions along a plane tangential to the second surface of the second sphere in the spherical coordinate system, where the different detector positions are separated by a distance finer than the pixel size of the radiation detector, and to assemble the radiographs to form a composite radiograph with a higher resolution than the acquired radiographs.

[0083] Example 8: In some examples of any one of the systems of Examples 1 to 7, the control unit is to obtain a series of radiographs at different detector positions along a plane tangential to the second surface of the second sphere in the spherical coordinate system, where the different detector positions are separated by a distance greater than the pixel size of the radiation detector but smaller than the physical size of the detector, and to assemble the radiographs to form a composite radiograph having an area larger than the physical size of the detector.

[0084] Example 9: In some examples, a computer-readable storage medium includes program instructions that, when executed by a system for non-destructive evaluation of an object placed on a stage, cause the system to determine, based on an input, a first position located on a first surface of a first sphere within a spherical coordinate system, and to determine, based on the input, a second position located on a second surface of a second sphere within the spherical coordinate system, where the second position is located opposite the first position with respect to the center of the spherical coordinate system, and to control the movement of a first robotic arm and the movement of a second robotic arm such that a radiation source and a radiation detector move to different positions among the first position and the second position.

[0085] Example 10: In some examples of the computer-readable medium of Example 9, the input indicates an imaging angle for evaluation of the object, and when the program instructions are executed, the system is further caused to determine the first position and the second position based on the imaging angle.

[0086] Example 11: In some examples of the computer-readable medium of Example 9 or Example 10, when the program instructions are executed, the system is caused to control the radiation source orientation of the radiation source such that radiation is directed from the radiation source position to the detector, and to control the detector orientation of the detector such that the detector is directed from the detector position to the radiation source, where the radiation source position and the detector position include different positions among the first position and the second position.

[0087] Example 12: In some examples of the computer-readable medium of any one of Examples 9 to 11, when the program instructions are executed, the system is caused to receive an input indicating a magnification for evaluation of the object, to determine a radiation source position that defines a radiation source radius based on the magnification, and to determine a detector position that defines a detector radius based on the magnification, where the sum of the detector radius and the radiation source radius divided by the radiation source radius is equal to the magnification, and the radiation source position and the detector position include different positions among the first position and the second position.

[0088] Example 13: In some examples of any one of Examples 9 to 12 of a computer-readable medium, when program instructions are executed, the radiation source is further caused to irradiate an object in response to controlling the movement of the radiation source robot arm and the detector robot arm.

[0089] Example 14: In some examples of any one of Examples 9 to 13 of a computer-readable medium, when program instructions are executed, the system is caused to acquire a series of radiographs at different detector positions along a plane that is tangential to the second surface of the second sphere in a spherical coordinate system, where the different detector positions are separated by a distance finer than the pixel size of the detector, and to assemble the radiographs to form a composite radiograph with a higher resolution than the acquired radiographs.

[0090] Example 15: In some examples, the method includes determining a first position located on the first surface of a first sphere in a spherical coordinate system based on an input to a system for non-destructive evaluation of an object placed on a stage, determining a second position located on the second surface of a second sphere in the spherical coordinate system based on the input, where the second position is located opposite the first position with respect to the center of the spherical coordinate system, and controlling the movement of a first robot arm and the movement of a second robot arm such that a radiation source and a radiation detector move to different positions among the first position and the second position.

[0091] Example 16: In some examples of the method of Example 15, the input indicates an imaging angle for evaluation of the object, and the method further includes determining a radiation source position and a detector position based on the imaging angle, where the radiation source position and the detector position include different positions among the first position and the second position.

[0092] Example 17: In some examples of the method of Example 15 or Example 16, the method further includes controlling the radiation source orientation of the radiation source such that radiation is directed from the radiation source position towards the detector, and controlling the detector orientation of the detector such that the detector is directed from the detector position towards the radiation source, wherein the radiation source position and the detector position include different positions among the first position and the second position.

[0093] Example 18: In some examples of the method of any one of Examples 15 to 17, the method includes receiving an input indicating a magnification for the evaluation of an object, determining a radiation source position that defines a radiation source radius based on the magnification, and determining a detector position that defines a detector radius based on the magnification, wherein the sum of the detector radius and the radiation source radius divided by the radiation source radius is equal to the magnification, and the radiation source position and the detector position include different positions among the first position and the second position.

[0094] Example 19: In some examples of the method of any one of Examples 15 to 18, the method further includes irradiating an object with the radiation source in response to controlling the movement of the first robotic arm and the second robotic arm.

[0095] Example 20: In some examples of the method of any one of Examples 15 to 19, the method includes acquiring a series of radiographs at different detector positions along a plane that is tangential to the second surface of the second sphere in a spherical coordinate system, wherein the different detector positions are separated by a distance finer than the pixel size of the detector, and assembling the radiographs to form a composite radiograph with a higher resolution than the acquired radiographs.

[0096] Various examples have been described. These examples and other examples are within the scope of the appended claims.

Claims

1. A system for non-destructive evaluation of an object, comprising: a first robotic arm; a radiation source coupled to the first robotic arm and configured to emit radiation; a second robotic arm; a radiation detector coupled to the second robotic arm and configured to measure the radiation emitted by the radiation source; a stage configured to support the object for non-destructive evaluation; a control unit; The control unit is configured to: determine a first position located on a first surface of a first sphere in a spherical coordinate system based on an input; determine a second position located on a second surface of a second sphere in the spherical coordinate system based on the input, wherein the second position is located opposite to the first position with respect to the center of the spherical coordinate system; control the movement of the first robotic arm and the second robotic arm such that the radiation source and the radiation detector move to respective positions among the first position and the second position; and is configured to perform the above. The control unit is further configured to: acquire a series of radiographs at different detector positions along a plane tangential to the second surface of the second sphere in the spherical coordinate system, wherein the different detector positions are separated by a distance finer than the pixel size of the radiation detector; assemble the radiographs to form a composite radiograph with a higher resolution than the acquired radiographs; and is further configured to perform the above. A system.

2. The control unit is configured to: receive the input indicating an imaging angle for evaluation of the object; determining the first position and the second position based on the imaging angle; The system according to claim 1, further configured to perform

3. The control unit controlling the radiation source orientation of the radiation source so that radiation is directed from the first position or the second position toward the radiation detector; controlling the detector orientation of the radiation detector so that the radiation detector is directed from the first position or the second position toward the radiation source; The system according to claim 1, further configured to perform

4. The control unit receiving the input indicating a magnification for evaluation of the object; determining a radiation source position defining a radiation source radius based on the magnification; determining a detector position defining a detector radius based on the magnification, wherein the sum of the radius of the radiation detector and the radiation source radius divided by the radiation source radius is equal to the magnification, and the radiation source position and the position of the radiation detector are each of the first position and the second position; The system according to claim 1, further configured to perform

5. The system according to claim 1, wherein the control unit is further configured to cause the object to be irradiated with radiation from the radiation source in response to controlling the movement of the first robotic arm and the second robotic arm.

6. The radiation detector includes a protective plate having at least one pressure sensor, and the protective plate is configured to disable the movement of the second robotic arm in response to the pressure sensor detecting contact with an article. The system according to claim 1.

7. The control unit Obtaining a series of radiographs at different detector positions along a plane located in a tangential direction with respect to the second surface of the second sphere in the spherical coordinate system, wherein the different detector positions are separated by a distance greater than the pixel size of the radiation detector but smaller than the physical size of the radiation detector; Assembling the radiographs to form a composite radiograph having an area larger than the physical size of the radiation detector; The system according to claim 1, further configured to perform.

8. A computer-readable storage medium including program instructions, When the program instructions are executed by a system for non-destructive evaluation of an object placed on a stage, the system is caused to: Determine a first position located on a first surface of a first sphere in a spherical coordinate system based on an input; Determine a second position located on a second surface of a second sphere in the spherical coordinate system based on the input, wherein the second position is located opposite to the first position with respect to the center of the spherical coordinate system; Control the movement of a first robotic arm and the movement of a second robotic arm so that a radiation source and a radiation detector move to respective positions among the first position and the second position; Cause to perform, When the program instructions are executed, the system is caused to: Obtain a series of radiographs at different detector positions along a plane located in a tangential direction with respect to the second surface of the second sphere in the spherical coordinate system, wherein the different detector positions are separated by a distance finer than the pixel size of the radiation detector; Assemble the radiographs to form a composite radiograph with a higher resolution than the obtained radiographs; A computer-readable storage medium that further causes to perform.

9. The input indicates an imaging angle for evaluating the object, and when the program instructions are executed, the system is further caused to determine the first position and the second position based on the imaging angle. The computer-readable storage medium according to claim 8.

10. When the program instructions are executed, the system controls the radiation source orientation of the radiation source so that radiation is directed from the radiation source position toward the radiation detector, and controls the detector orientation of the radiation detector so that the radiation detector is directed from the detector position toward the radiation source, wherein the radiation source position and the position of the radiation detector each include one of the first position and the second position, and the computer-readable storage medium according to claim 8 is further caused to perform.

11. When the program instructions are executed, the system receives the input indicating a magnification for evaluating the object, determines a radiation source position that defines a radiation source radius based on the magnification, and determines a detector position that defines a detector radius based on the magnification, wherein the sum of the radius of the radiation detector and the radiation source radius divided by the radiation source radius is equal to the magnification, and the radiation source position and the position of the radiation detector each include one of the first position and the second position, and the computer-readable storage medium according to claim 8 is further caused to perform.

12. When the program instructions are executed, the radiation source is further caused to irradiate the object in response to controlling the movement of the first robotic arm and the second robotic arm. The computer-readable storage medium according to claim 8.

13. Determining a first position located on a first surface of a first sphere within a spherical coordinate system based on an input to a system for non-destructive evaluation of an object disposed on a stage; Determining a second position located on a second surface of a second sphere within the spherical coordinate system based on the input, wherein the second position is located opposite to the first position with respect to the center of the spherical coordinate system; Controlling the movement of a first robotic arm and the movement of a second robotic arm such that a radiation source and a radiation detector move to respective positions among the first position and the second position; comprising; Obtaining a series of radiographs at different detector positions along a plane tangential to the second surface of the second sphere within the spherical coordinate system, wherein the different detector positions are separated by a distance finer than the pixel size of the radiation detector; Assembling the radiographs to form a composite radiograph with a higher resolution than the obtained radiographs; further comprising a method.

14. The input indicates an imaging angle for evaluation of the object, and the method further comprises determining a radiation source position and a detector position based on the imaging angle, wherein the radiation source position and the position of the radiation detector include respective positions among the first position and the second position, according to the method of claim 13.

15. Controlling the radiation source direction of the radiation source such that radiation is directed from the radiation source position towards the radiation detector; Controlling the detector direction of the radiation detector such that the radiation detector is directed from the detector position towards the radiation source, wherein the radiation source position and the position of the radiation detector include respective positions among the first position and the second position; further comprising the method of claim 13.

16. Receiving the input indicating a magnification for evaluation of the object; Determining a radiation source position defining a radiation source radius based on the magnification; Determining a detector position defining a detector radius based on the magnification, wherein a sum of the radius of the radiation detector and the radiation source radius divided by the radiation source radius is equal to the magnification, and the radiation source position and the position of the radiation detector include respective positions of the first position and the second position; The method according to claim 13, further comprising: **Claim 17** The method according to claim 13, further comprising irradiating the object with the radiation source in response to controlling movements of the first robotic arm and the second robotic arm.

Images