System and method for generating high-energy three-dimensional computed tomography images of bulk material

Abstract

A system for inspecting an object, comprising: an X-ray radiation source; a horizontal detector array, wherein the source and the detector array are substantially disposed on a first plane; a platform configured to rotate and translate along a vertical trajectory, where the platform is disposed on a second plane between the source and the detector array, and where the object is disposed on the platform; and a computing device configured to cause the source to emit a substantially horizontal fan-shaped beam in a third plane, where the third plane is above the top of the object; acquiring calibration data from the detector array when the third plane is above the top of the object; rotating the platform at the same time and lifting the object vertically upwards; acquiring scanning data of the object; and generating a three-dimensional scanning image of the object.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This specification relies on the priority of U.S. Patent Provisional Application No. 63 / 375,900, entitled “Systems and Methods for Generating High-Energy Three-Dimensional Computer Tomography Images of Bulk Materials,” filed on September 16, 2022. The above application is incorporated herein by reference in its entirety. Technical Field

[0003] The present specification generally relates to the field of X-ray inspection. More specifically, the present specification relates to systems and methods for moving an object vertically along a spiral trajectory through a horizontal fan-shaped X-ray beam to generate a three-dimensional scanned image of the object. Background Art

[0004] In recent years it has become apparent that the methods employed for screening personnel baggage (both "carry-on" and "hold" baggage) are insufficient to fully characterize the contents of larger aviation packages. A Unit Load Device (ULD) is a container used to carry baggage, cargo and mail on wide-body aircraft. ULDs vary in size but are typically no larger than 2m in width, 1m in length and approximately 1.5m in height. Such large dimensions require X-ray penetrating powers far greater than those provided by the <200keV source solutions employed in baggage scanners. Even scanning solutions up to 1MeV are limited by their ability to penetrate <100mm of steel equivalent, which prevents full inspection of densely or highly packed large ULD type containers.

[0005] Air cargo operations also require the use of dual or multi-sided inspection technology to provide the operator with complete visualization of the object being inspected and the potential threats or contraband within. This requirement is particularly important and beneficial when considering larger, heavier packaged and densely packed cargo, where objects can overlap and “clutter” the inspection view from many angles. In fact, when considering checked baggage, where the most stringent ECAC (European Civil Aviation Conference) regulations (and equivalent TSA (US Transportation Security Administration) regulations) are in place, most airports are required to utilize CT (Computed Tomography) imaging technology.

[0006] CT imaging of items up to and including the person holding the baggage can be achieved using energies similar to those of carry-on baggage scanners or in the energy range of <200keV. This is due in part to the maximum size of bags inspected, and in part to the typical low-density materials that people pack into their travel bags - i.e., clothing, toiletries, and other typical consumer goods. However, for larger consignments that may include more densely and tightly packed objects (such as, for example, lithium batteries, food, and electronic devices), a 200keV source does not provide enough penetration to adequately image the package.

[0007] Recently, the observation of shipments of pharmaceuticals packed in palletized foods has increased, so similar solutions to those in the above market sectors are needed to provide complete inspection of palletized goods. ISO guidelines recommend that the dimensions of the pallet be no larger than 1100mm × 1220mm × 1830mm (length × width × height). For the transport of relatively high-density fruit with a high fill rate, a penetration thickness of 1.1m can correspond to an equivalent steel thickness of over 300mm. This penetration capability requires the use of high-energy solutions in order to achieve the necessary contrast and detection capabilities for inspection.

[0008] In addition to driving significant additional costs in terms of the increased technical capabilities of the imaging solution and the management and shielding of the greater X-ray dose emission, this requirement introduces a number of complexities in the solutions available to provide 3D imaging capabilities. Most CT imaging solutions rely on the ability to rotate the X-ray source and detector assembly at high speeds. This works well for low profile X-ray sources such as tubes or simple emitter devices, but does not scale well to high energy sources in the ~6MeV range. Similarly, static CT imaging devices that employ multiple individual X-ray sources do not provide a comparable solution that can be sought with much larger and bulky MeV solutions.

[0009] Therefore, there is a need for an X-ray imaging system and method that incorporates fixed inspection hardware while providing a 3D image of the inspected object. There is also a need for an X-ray imaging system and method that relies on the motion of the object under inspection, eliminating the need for mobile inspection hardware and the need to employ multiple X-ray source and detector configurations because many of the angles at which the object is imaged are generated by the motion of the object itself. Summary of the invention

[0010] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools, and methods, which are intended to be exemplary and illustrative, not limiting in scope.This application discloses many embodiments.

[0011] In some embodiments, the present specification relates to a system for inspecting an object, comprising: an X-ray radiation source; a horizontal detector array, wherein the source and the detector array are substantially disposed on a first plane; a platform, the platform being configured to rotate and configured to translate along a vertical trajectory, wherein the platform is disposed on a second plane between the source and the detector array, and wherein the platform is suitable for receiving and supporting the object; and a computing device configured to: cause the source to emit a substantially horizontal fan-shaped X-ray beam in a third plane, wherein the third plane is above the top of the object; acquire calibration data from the detector array when the third plane is above the top of the object; cause the platform to simultaneously rotate and vertically raise the object upward; acquire scan data of the object; and use the calibration and scan data to generate a three-dimensional scanned image of the object.

[0012] Optionally, the objects or objects being inspected are densely packed unit load devices or pallets.

[0013] Optionally, the source is a LINAC or a betatron configured to operate at energies in the range from about 750 keV up to 10 MeV. Optionally, the source has a dose output in the range of 0.01 Gy / min to 30 Gy / min. Optionally, the source comprises a secondary collimator configured to generate a horizontal fan X-ray beam.

[0014] Optionally, the detector array is 1 to 6 channels or pixels high. Still optionally, the detector array is 8 to 12 channels or pixels high. Still optionally, the detector array has channels or pixels ranging from 1 to 20.

[0015] Optionally, the system has a magnification of approximately 1.525 and a reconstruction resolution of approximately 22 mm per slice.

[0016] Optionally, the system has a throughput of at least 5 units per hour.

[0017] Optionally, the platform includes a first drive mechanism and a second drive mechanism, the first drive mechanism is configured to rotate the object at a first rotation speed, and the second drive mechanism is configured to rotate the object at a second rotation speed. Optionally, the first rotation speed ranges from about 5 minutes per revolution to 30 seconds per revolution, and wherein the second speed ranges from about 30 seconds per revolution to 0.5 seconds per revolution.

[0018] Optionally, the platform also includes an auger / scissor lift to raise or lower objects.

[0019] Optionally, the platform further comprises a lift that is raised and lowered by a piston assembly to raise or lower the object.

[0020] In some embodiments, the present specification relates to a method for inspecting an object using a platform placed between an X-ray radiation source and a horizontal detector array, the method comprising: transporting the object on a conveyor to place the object on the platform; triggering the source to emit a horizontally diverging fan beam, wherein the plane of the fan beam is above the top surface of the object; acquiring calibration data using the detector array; rotating the platform and raising it vertically upward so that the object moves in a substantially spiral trajectory; acquiring scanning data by exposing the moving object to the fan beam; and generating a three-dimensional scanned image of the object using the calibration and scanning data.

[0021] Optionally, the objects are densely packed unit load devices or pallets.

[0022] Optionally, the source is a LINAC or a betatron configured to operate at energies in the range from about 750 keV up to 10 MeV. Optionally, the source has a dose output in the range of 0.01 Gy / min to 30 Gy / min. Optionally, the source comprises a secondary collimator configured to generate a horizontal fan-shaped X-ray beam.

[0023] Optionally, the detector array is 1 to 6 channels or pixels high. Optionally, the detector array is 8 to 10 channels or pixels high. Optionally, the detector array has channels or pixels ranging from 1 to 20.

[0024] Optionally, the method is capable of achieving a magnification of approximately 1.525 and a reconstruction resolution of approximately 22 mm per slice.

[0025] Optionally, the method is capable of having a throughput of at least 5 units per hour.

[0026] Optionally, the platform includes a first drive mechanism and a second drive mechanism, the first drive mechanism is configured to rotate the object at a first rotation speed, and the second drive mechanism is configured to rotate the object at a second rotation speed. Optionally, the first rotation speed ranges from about 5 minutes per revolution to 30 seconds per revolution, and wherein the second speed ranges from about 30 seconds per revolution to 0.5 seconds per revolution.

[0027] Optionally, the platform also includes an auger / scissor lift to raise or lower the object. Optionally, the platform also includes a hoist that is raised and lowered by a piston assembly to raise or lower the object.

[0028] Optionally, the method further comprises: moving the platform vertically downward when the entire height of the object has been scanned; and transporting the item away from the platform while conveying another item toward the platform.

[0029] In some embodiments, the present specification relates to a system for inspecting an object, comprising: an X-ray radiation source; a horizontal detector array, wherein the source and the detector array are substantially disposed in a first plane, and wherein the detector array comprises channels or pixels ranging from 1 to 20; a platform, the platform being configured to rotate and translate along a vertical trajectory, wherein the platform is disposed in a second plane between the source and the detector array, and wherein the object is disposed on the platform; and a computing device configured to: cause the source to emit a substantially horizontal fan-shaped X-ray beam in a third plane, wherein the third plane is above the top of the object; acquire calibration data from the detector array when the third plane is above the top of the object; cause the platform to simultaneously rotate and vertically raise the object upward; acquire scan data of the object; use the calibration and scan data to generate a three-dimensional scanned image of the object; and move the platform vertically downward to the second plane once the entire height of the object has been irradiated by the fan beam.

[0030] Optionally, the objects are densely packed unit load devices or pallets.

[0031] Optionally, the platform does not rotate when moving vertically downward.

[0032] Optionally, the platform continues to rotate while moving vertically downward.

[0033] The foregoing and other embodiments of the present specification will be described in more depth in the drawings and detailed description provided below. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The accompanying drawings illustrate various embodiments of the system, method, and embodiments of various other aspects of the present disclosure. It will be understood by those of ordinary skill in the art that the element boundaries (e.g., boxes, groups of boxes, or other shapes) shown in the figures represent an example of boundaries. It is possible that, in some examples, an element may be designed as multiple elements, or multiple elements may be designed as one element. In some examples, an element shown as an internal component of an element may be implemented as an external component in another element, and vice versa. In addition, the elements may not be drawn to scale. A non-restrictive and non-exhaustive description is described with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, but the emphasis is placed on the explanation principle.

[0035] Figure 1A is a perspective view of a central scanning housing or object of an X-ray inspection system according to some embodiments of the present specification;

[0036] Figure 1B is a diagram of an X-ray inspection system according to some embodiments of the present specification;

[0037] Figure 2 shows a LINAC-based source placed at a height according to some embodiments of the present specification;

[0038] Figure 3A is a block diagram illustration showing a first configuration of a detector array according to some embodiments of the present specification;

[0039] Figure 3B is a block diagram illustration showing a second configuration of a detector array according to some embodiments of the present specification;

[0040] Figure 3C According to some embodiments of this specification Figure 3A a perspective view of a first configuration of the detector array shown;

[0041] Figure 3D shows a perspective view of a level detector box or housing according to some embodiments of the present specification;

[0042] Figure 4A shows a perspective view of a platform or workbench according to some embodiments of the present specification;

[0043] Figure 4B shows a first plan view of a platform or table according to some embodiments of the present specification;

[0044] Figure 4C shows a second plan view of a platform or table according to some embodiments of the present specification;

[0045] Figure 4D A blueprint design showing a plan view of some embodiments according to the present specification, including Figure 4A , 4B and a first side view and a second side view of the platform or workbench shown in 4C; and

[0046] Figure 5 is a flow chart of a plurality of exemplary steps of a method for operating a system installed in a housing according to a first embodiment of the present specification. Specific embodiments

[0047] This specification relates to multiple embodiments. The following disclosure is provided to enable one of ordinary skill in the art to practice the present invention. The language used in this specification should not be interpreted as a general negation of any one specific embodiment or used to limit the meaning of the claims beyond the terms used therein. Without departing from the spirit and scope of the present invention, the general principles defined herein can be applied to other embodiments and applications. In addition, the terms and wordings used are for the purpose of describing exemplary embodiments and should not be considered restrictive. Therefore, the present invention will be given the widest scope including many substitutions, modifications and equivalents consistent with the disclosed principles and features. For the sake of clarity, details related to technical materials known in the technical field related to the present invention are not described in detail to avoid unnecessary obscurity of the present invention.

[0048] In various embodiments, the computing device includes an input / output controller, at least one communication interface, and a system memory. The system memory includes at least one random access memory (RAM) and at least one read-only memory (ROM). These elements communicate with a central processing unit (CPU) to implement the operation of the computing device. In various embodiments, the computing device can be a conventional stand-alone computer, or alternatively, the functionality of the computing device can be distributed across multiple computer systems and architectures.

[0049] In some embodiments, the execution of multiple program instructions or code sequences causes or causes the CPU of the computing device to perform various functions and processes. In alternative embodiments, hard-wired circuits can be used instead of software instructions or in combination with software instructions to implement the processing of the systems and methods described in this application. Therefore, the described systems and methods are not limited to any specific combination of hardware and software.

[0050] In the specification and claims of the present application, each of the words "includes," "comprising," "having," "containing," and forms thereof is not necessarily limited to the members of the list associated with the word. Therefore, they are intended to be equivalent in meaning and open-ended, in that one or more items following any of these words is not meant to be an exhaustive list of such one or more items, or to be limited to the listed one or more items. It should be noted herein that any feature or component described in association with a particular embodiment may be used and implemented with any other embodiment unless expressly indicated otherwise.

[0051] It must also be noted that, as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context dictates otherwise. Although any systems and methods similar or equivalent to those described herein can be used to practice or test embodiments of the present disclosure, the preferred systems and methods are now described.

[0052] Overview

[0053] Figure 1A is an X-ray inspection system 100 ( Figure 1B ) is a perspective view of an enclosure or housing 101 of a housing 101. The enclosure 101 has an entry screen door 102 into a tunnel 104, which leads to an inspection area or zone 106, which in an embodiment is also referred to as an inspection box or central scanning enclosure. The inspection area, zone or central scanning enclosure 106 further transitions into an exit tunnel 108 having an exit screen door 110. For scanning, a conveyor 112 is configured to convey an object to be inspected (OUI) 125 ( Figure 1B ) is transported through the entry gate 102 and into the tunnel 104 so that the OUI 125 is placed in the inspection area or zone 106. After being scanned in the inspection area, zone or central scanning housing 106, the OUI 125 is transported by the conveyor 112 to the exit tunnel 108 and exits through the exit gate 110.

[0054] Figure 1B 1 is an illustration of an x-ray inspection system 100 according to some embodiments of the present specification. The x-ray inspection system 100 is mounted within a central scanning housing 106 of a housing shell 101 (in an inspection zone or region). The system 100 includes a platform or table 115 disposed between a high-dose, high-energy x-ray radiation source 118 and a detector array 120. The source 118 and the detector array 120 are disposed at a height above the floor of the inspection zone or region 106, while the platform or table 115 is disposed on or near the floor of the inspection zone, region or central scanning housing 106. In other words, the platform or table 115 is disposed on a first plane, while the source 118 and the detector array 120 are disposed generally on a second plane, wherein the second plane is at a height above the first plane.

[0055] In an embodiment, the detector array 120 is a horizontal array of pixelated detectors. The detector array 120 can be two-dimensional - that is, having multiple rows of detectors. As a non-limiting illustration, Figure 3D A horizontal detector box or housing 310 including a plurality of detectors 315 is shown.

[0056] In some embodiments, the detector array 120 can be formed by a crystal stack that generates an analog signal when an X-ray impinges thereon, wherein the signal strength is proportional to the amount of beam attenuation in the OUI 125. In one embodiment, the X-ray beam detector arrangement consists of a linear array of solid-state detectors of the crystal diode type. A typical arrangement uses a cadmium tungstate scintillator crystal to absorb X-rays transmitted through the OUI 125 and convert the absorbed X-rays into photons of visible light. As known to those of ordinary skill in the art, crystals such as bismuth germanate, sodium iodide or other suitable crystals may be used instead. The crystal may be directly coupled to a suitable detector, such as a photodiode or a photoamplifier. The detector photodiode may be arranged linearly, which provides advantages over photoamplifiers in terms of operating range, linearity and detector-to-detector matching through a unity gain device.

[0057] The computing device is in data communication with the source 118, the platform 115, the detector array 120, and the conveyor 112. The conveyor 112 transports and places the OUI 125 on the platform 115 for scanning upon receiving a control signal from the computing device.

[0058] In various embodiments, the OUI 125 includes bulk materials, large packages and objects such as, but not limited to, ULD (unit load device) containers with densely packed goods and palletized goods / cargo. The entrance door 102 and exit door 110 of the enclosure 101 are of sufficient size to accommodate typical pallet and ULD sizes. In various embodiments, the spacing between the source 118 and the detector array 120 is such that for a given emission angle and detector range, objects of all sizes residing on the platform or table 115 have their full range scanned.

[0059] In both air and palletized freight scenarios, multiple scanning system setups may be considered. For example, each scanning system setup (for air and palletized freight scenarios) has different throughput requirements. Therefore, the inspection system of the present specification allows flexibility to achieve the necessary throughput for any given setup / deployment.

[0060] According to some purposes, the inspection system of the present specification utilizes a dual motor / gearbox configuration of a platform or table to allow operation at multiple speeds using otherwise identical / common rotational hardware. Each setting for aviation and palletized freight scenarios may require a different dose output, and therefore the inspection system of the present specification uses an adjustable dose-modulated X-ray source. When deployed in scenarios such as aviation and palletized freight, the inspection system of the present specification may need to scan at different throughputs while still needing to achieve the same average dose footprint - which would require the dose output of the source to be halved. In addition, in situations where the inspection system of the present specification requires minimal performance but has constraints on dose and throughput, it is desirable to allow a flexible detector architecture that simply increases or decreases the number of detector columns without significant other hardware changes.

[0061] It should also be understood that the inspection system of the present specification is also used outside of secure spaces. That is, non-destructive testing of large, heavy and high-density objects to inspect internal components, monitor behavior over time, or analyze structural defects or inconsistencies. Many NDE (non-destructive evaluation) facilities require hardware to be delivered for inspection. This is time-consuming and expensive, and in some cases, it is impossible given the restrictions on moving fragile, expensive and / or dangerous (including radioactive) materials. Therefore, the inspection system of the present specification provides a deployable inspection platform for operation at the customer site and can be configured to meet the specific performance, dose and throughput requirements of the facility.

[0062] Radiation Source

[0063] When triggered or activated by the computing device, the source 118 is configured to irradiate the OUI 125 with a horizontal diverging fan beam 130 of pulsed X-rays. That is, the central axis of the fan beam 130 is substantially horizontal. It will be understood by those skilled in the art that the use of a two-dimensional detector array 120 requires the use of a "wide" or "conical" type beam, which inherently has a slight angular deviation from the true horizontal plane. In an embodiment, the angular deviation of the beam from the horizontal plane ranges between 0 and 2.5 degrees. However, this deviation is corrected by using a reconstruction algorithm. The high-energy radiation source 118 can be, but is not limited to, a high-dose, high-energy linear accelerator (LINAC) or an electron beta accelerator. The selection of the source type, its intensity and energy output depends on the sensitivity of the detector, the radiographic density of the objects in the space between the source and the detector, radiation safety considerations and operational requirements, such as inspection speed. It will be understood by those skilled in the art that factors need to be considered in order to select the type of radiation source according to the inspection requirements. In one embodiment, where OUI 125 is a large ULD that highly attenuates an X-ray beam, the radiation may come from an X-ray source operating in an energy range from about 750 keV or even up to 10 MeV or more. As a non-limiting example, the large ULD may have dimensions of up to 156 cm x 15 cm x 162 cm.

[0064] In some embodiments, radiation source 118 uses interleaved dual energy pulses to generate low energy (ranging from 3 MeV to 5 MeV) and high energy (ranging from 6 MeV to 9 MeV) X-ray scan images of OUI 125 .

[0065] Figure 2 A LINAC-based source 218 is shown placed at a height and having a horizontally mounted secondary collimator 210. The secondary collimator 210 is configured to shape the X-ray beam emitted by the source 218 into a substantially horizontally diverging fan beam. In an embodiment, the LINAC 218 or any other source provides a radiation dose sufficient to image the ULD and the tray. In an embodiment, the energy and dose output of the LINAC or any other source range from 750keV to 10MeV and 0.01Gy / min to 30Gy / min, respectively.

[0066] It should be understood that the source 218 needs to be positioned at a height such that the horizontally diverging fan beam is not obstructed when pulsed at the beginning of the scan (and the OUI is stationary). Therefore, with a maximum tray height of approximately 2.m, the source 218 must be placed at a height of at least 2.2m. Taking into account the lifting and rotation mechanism on which the OUI resides, in an embodiment, the source 218 can be placed at a height of approximately 2.5m, with a 1m deviation (+ / -1m) in either direction. In other words, the height at which the source 218 is positioned can be in the range of 1.5m to 3.5m.

[0067] Platform or workbench

[0068] The platform or workbench 115 is configured to rotate and move or translate vertically up and down (i.e., along a vertical trajectory) when receiving a control signal from a computing device. This causes the OUI 125 placed on the platform 115 to be rotated and moved vertically up and down. In some embodiments, the OUI 125 (placed on the platform 115) moves up and down along a spiral trajectory. In some embodiments, the OUI 125 (placed on the platform 115) moves up along a spiral trajectory and moves down along a vertical trajectory. In some embodiments, the OUI 125 (placed on the platform 115) moves up and down along a vertical trajectory. In some embodiments, the OUI 125 (placed on the platform 115) moves vertically upward and rotates in the following step sequence: the OUI 125 moves vertically upward by a predetermined step length or height, stops moving vertically upward and then rotates while remaining stationary in the vertical direction. After a complete rotation, the OUI 125 stops rotating and moves vertically upward by a predetermined step length or height again. This sequence of step-by-step vertical and rotational movements is repeated until the entire height of the OUI 125 has been scanned. The step-by-step sequence of vertical and rotational movements is desirable when the OUI 125 needs to be moved very slowly so as not to damage the contents. Thereafter, the OUI 125 moves downward along a vertical trajectory or along a step-by-step vertical trajectory (without any rotational movement).

[0069] It should be understood that the OUI 125 must be raised through its entire height so that the entire OUI passes through the X-ray beam 130. Therefore, the height of the vertical trajectory / motion is approximately equal to the height of the horizontal fan beam from the floor - that is, the positioning height of the source 118. Therefore, in some embodiments, the height of the vertical trajectory / motion is up to about 2.5 m for a large pallet. For the movement of the OUI 125 along the spiral trajectory, the number of rotations of the platform or table 115 (and therefore the OUI 125) depends on the height of the scan and the size of the detector array 120. As a non-limiting example, for a 6-wide detector array (small X-ray cone) and a 2.2 m OUI height, 100 rotations are required. On the other hand, for a 20-wide array (large X-ray cone), only 30 rotations are required.

[0070] According to some embodiments of this specification, Figure 4A A perspective view of a platform or workbench 115 is shown, and Figure 4B and 4C A first and second plan view of a platform or table 115 is shown. Referring now to Figure 4A , 4B4C, in some embodiments, the platform or table 115 includes a first support member 402 placed on top of a second support member 404. The first support member 402 is configured to rotate (helical rotation) and translate (vertically up and down), while the second support member 404 is placed in the inspection box, area or region (central scanning housing) 106 ( Figure 1A ) on the floor of or near the floor of the inspection box, area or area (central scanning housing) 106.

[0071] According to some embodiments, the first support member 402 is configured to rotate at a first scanning speed and a second scanning speed. In an embodiment, the first scanning speed is slower than the second scanning speed. In an embodiment, the first scanning speed is equal to the second scanning speed. In an embodiment, the second scanning speed is slower than the first scanning speed. To achieve the first scanning speed and the second scanning speed, the platform or workbench 115 includes a first drive mechanism 412 having a first gear box 412a and a motor assembly 412b and a second drive mechanism 414 having a second gear box 414a and a motor assembly 414b. Figure 4D A plan view 430 and a first side view 432 and a second side view 434 of a platform or table 115 according to some embodiments of the present specification are shown. The figure shows a first drive gear 412a and a first low speed motor 412b of a first drive mechanism 412, a second drive gear 414a and a second high speed motor 414b of a second drive mechanism 414, and a slewing ring 410.

[0072] The platform or table 115 includes a shaft attached to the bottom of the first support member 402 and protruding downward into the void in which the first drive mechanism 412 and the second drive mechanism 414 are mounted. The first drive mechanism 412 and the second drive mechanism 414 include two sliding drives that move to engage with the slewing ring 410, which is in turn mounted on the underside of the first support member 402. Within this space, below the first support member 402, there is an encoder shaft that passes down through the center of the slewing ring 410 and is placed between the first drive mechanism 412 and the second drive mechanism 414 on either side, which is configured to provide electrical feedback / signals of the angular position of the slewing ring / rotating platform to a PLC (Programmable Logic Controller) that is in data communication with a computing device during scanning. The first drive mechanism 412 and the second drive mechanism 414 are both mounted on a common frame so that they can slide so that only one drive gear 412a or 414a is engaged with the slewing ring 410 at any one time.

[0073] Based on control signals from the computing device to the PLC, each of the first drive mechanism 412 and the second drive mechanism 414 can be automatically driven into and out of position (so as to drive the slewing ring 410 and thus rotate the first support member 402) according to the range of imaging speeds required. In an embodiment, when engaged, the first drive mechanism 412 with the larger, slower rotating gearbox assembly 412a allows operation at rotational speeds ranging from about 5 minutes per revolution (very high performance imaging) to 30 seconds per revolution, while the second drive mechanism 414 with the smaller, faster rotating gearbox assembly 414a allows much faster rotational speeds ranging from about 30 seconds per revolution to 0.5 seconds per revolution.

[0074] In addition, the platform or table 115 includes a lifting mechanism to enable the first support member 402 to translate vertically up and down. In some embodiments, the lifting and lowering mechanism is a screw lift / scissor lift that raises or lowers the first support member 402 while the second support member 404 remains firmly placed on the floor. In some embodiments, the lifting and lowering mechanism is a hoist that is raised and lowered by a piston assembly seat at a height. In various embodiments, the lifting mechanism is characterized by having: a) smooth motion, b) feedback from a proximity / distance sensor at a height during scanning (resolution ranges between 0.5 mm and 3 mm depending on detector size and spacing).

[0075] In various embodiments, the system 100 has a throughput of 5 units to 30 units per hour. In various embodiments, the system 100 has a throughput of at least 5 units per hour. In embodiments, higher throughput can be achieved by capturing scan images without rotating the platform or table 115. In this case, vertical motion can be performed at a faster speed, with scan times of seconds instead of minutes.

[0076] In various embodiments, the rates of vertical translation (or lift) and rotational movement are determined by one or more of the following factors:

[0077] The maximum speed at which the OUI 125 can rotate is based on safety, content and / or structure. In an embodiment, but not limited to such an embodiment, the speed is less than 5 seconds per revolution.

[0078] Desired maximum and / or minimum LINAC (source 118) pulse frequency. In some embodiments, the LINAC pulse frequency is in the range of 50 Hz to 1000 Hz, or increments therein, but is not limited to such a range.

[0079] The height of the detector array 120, which corresponds to the extent of the two-dimensional array 120, and in particular, to the number of independent detector pixel elements in the vertical direction. In some embodiments, the height of the detector array ranges from a single row up to 20, i.e., from about 6 mm to 20×6 mm.

[0080] The maximum and / or minimum speeds that can be achieved by the first drive mechanism 412 and the second drive mechanism 414. In some embodiments, the speed of the first drive mechanism 412 is less than 1 second per revolution, and the speed of the second drive mechanism 414 is greater than 1 second per revolution.

[0081] Desired throughput. In some embodiments, the throughput ranges from 5 to 30 units or pallets per hour. In various embodiments, the system 100 has a throughput of at least 5 units per hour.

[0082] Desired Image Performance. In some embodiments, the desired image performance corresponds to standard HE (high energy) image performance specifications of penetration / grid resolution / line detection / contrast.

[0083] The shielding design of the given system 100 provides a desired time-averaged dose to the ambient environment. In some embodiments, the dose to the ambient environment is maintained below 0.5 uSV per hour to comply with the standard.

[0084] Return to reference Figure 1B According to some embodiments, for scanning, OUI 125 resides on a platform or table 115 that allows OUI 125 to move vertically upward while being simultaneously rotated (i.e., along a spiral trajectory). As OUI 125 moves along the spiral path, it passes through a horizontal X-ray fan beam 130. Beam 130 is incident on a horizontal detector array 120, thereby generating image slices of OUI 125 as it passes through beam 130. A 3D image of OUI 125 is then reconstructed using standard filtered back projection techniques for inspection.

[0085] Exemplary Imaging / Scanning Parameters

[0086] Return to reference Figure 1B , system 100 is characterized by the following exemplary parameters. In some embodiments, Figure 3A As shown, the first configuration of the detector array 120a is 6 channels or pixels 302 high / height, with a centerline to centerline spacing of approximately 5.6 mm. This gives a total per-pulse image slice of 33.6 mm. In some embodiments, the first configuration of the detector array 120a is 1 to 6 channels or pixels 302 high / height. Figure 3C A perspective view of the detector array 120a is shown with the 3D tungsten printed collimator 310 placed on top.

[0087] In some embodiments, Figure 3B As shown, the second configuration of the detector array 120b is 8 channels or pixels 304 high / height. In some embodiments, the second configuration of the detector array 120b is 8 to 12 channels or pixels 304 high / height. In some embodiments, the detector arrays 120a, 120b use the same bracket, PCB and mounting hardware to provide optimal performance and flexibility in throughput and scanning speed. In various embodiments, the number of channels or pixels (in the detector array 120) can be configured between 1 and 20.

[0088] In some embodiments, source 118 is positioned to have a target to detector array distance of approximately 6.1 m along the central axis, and the center of OUI 125 is approximately 4 m from the target. In various embodiments, the target to detector array distance along the central axis ranges from 4 to 8 m, and the center of OUI 125 ranges from 3 to 6 m from the target.

[0089] In some embodiments, the system 100 has a magnification of about 6.1 / 4 = 1.525. This gives a reconstruction resolution of about 22 mm per slice. In some embodiments provided only as examples and not meant to be limiting, we assume that the total height "h" of the OUI 125 is about 1000 mm. This will require 45 turns (1000 / 22). Therefore, for each rotation or turn, the OUI 125 will move vertically 22 mm (i.e., a slice width of 22 mm). In other words, there are about 45×22 mm slices in the 1000 mm height of the OUI 125.

[0090] In an embodiment, since the enclosure 101 needs to accommodate pallets or ULDs having a maximum height of up to 1.83 m or 72 inches (according to ISO standards), the system will require an enclosure of at least twice that value. Therefore, in an embodiment, the overall height 'H' of the central scanning enclosure (inspection zone or area) 106 is at least twice (2x) the maximum height of the OUI 125, since the entire height of the OUI 125 needs to pass through the scanning fan beam 130. In some embodiments, the overall height 'H' of the central scanning enclosure (inspection zone or area 106), also taking into account the conveyor system height and headroom clearance, ranges from 3.5 m to 10 m, and is preferably 5 m.

[0091] In various embodiments, the platform or table 115 is configured to rotate through a wide range of values ​​based on which of the first drive mechanism 412 or the second drive mechanism 414 is engaged / used. When engaged, the first drive mechanism 412 with the larger, slower rotating gearbox assembly 412a allows operation at speeds between about 5 minutes per revolution (very high performance imaging) and 30 seconds per revolution, while the second drive mechanism 414 with the smaller, faster rotating gearbox assembly 414a allows much faster rotation between 30 seconds per revolution and 0.5 seconds per revolution. In one embodiment, when the first drive mechanism 412 is engaged, the platform or table 115 can rotate at a speed of, for example, 10 seconds per revolution. In one embodiment, when the second drive mechanism 414 is engaged, the platform or table 115 can rotate at a speed of, for example, 5 minutes per revolution.

[0092] In some embodiments, the width of the detector array 120 is approximately 3.6 m. With a horizontal spacing of 6.1 mm, this gives the number of sampling points per projection line 'S' = 590. Therefore, the number of required projections 'P' is then approximately equal to S*pi / 2 = 927 (assuming 1000). This in turn is equal to 1 projection per 0.36 degrees.

[0093] The rotation speed (of the platform or table 115) is now 10 seconds per revolution = 0.01 seconds per projection = 100 Hz LINAC (source 118) pulse repetition frequency. Furthermore, 10 seconds per revolution and 45 revolutions per scan = 450 seconds = 7.5 minutes (neglecting vertical motion of the platform or table 115). From this, the following scan parameters can be extrapolated: (i) 200 Hz LINAC - 5 seconds per revolution - 3.25 minutes per scan, and (ii) 400 Hz LINAC - 2.5 seconds per revolution - 1.625 minutes per scan.

[0094] In various embodiments, the system 100 has a throughput of 5 units to 30 units per hour. In various embodiments, the system 100 has a throughput of at least 5 units per hour.

[0095] Scanning Method

[0096] Figure 5 is a flowchart of a plurality of exemplary steps of a method 500 for operating a system 100 installed in a housing 101 according to a first embodiment of the present specification. Figure 1A , Figure 1B and Figure 5At step 502, the platform or table 115 is configured to rotate and move vertically upward to achieve a desired scanning speed. At least one of the first drive mechanism 412 or the second drive mechanism 414 is engaged to enable the platform or table 115 to rotate at the desired rotational speed. Similarly, the lifting mechanism is engaged to enable the platform or table 115 to move vertically upward at the desired translation speed.

[0097] At step 504, OUI 125 is placed on conveyor 112, which is configured to transport OUI 125 into inspection box, zone or area 106 and place OUI 125 on platform or workbench 115. When OUI 125 reaches the center of inspection box, zone or area 106, the screen door of entry door 102 is closed.

[0098] At step 506, the source 118 is configured to emit the horizontal fan beam 130 and capture calibration data. At this time, the total height (or the first plane of the top) of the OUI 125 is placed below the second plane of the horizontal fan beam 130. Therefore, the detector array 120 is configured to acquire an X-ray scan signal corresponding to the horizontal fan beam 130 that is not blocked by the OUI 125. The computing device is configured to generate calibration data corresponding to the unblocked X-ray scan signal.

[0099] At step 508, the platform or table 115 is configured to simultaneously raise and rotate the OUI 125. In some embodiments, the OUI 125 (placed on the platform 115) moves up and down along a spiral trajectory. In some embodiments, the OUI 125 (placed on the platform 115) moves up along a spiral trajectory and moves down along a vertical trajectory. In some embodiments, the OUI 125 (placed on the platform 115) moves up and down along a vertical trajectory. In some embodiments, the OUI 125 (placed on the platform 115) moves vertically upward and rotates in a step-by-step sequence as follows: the OUI 125 moves vertically upward by a predetermined step length or height, stops moving vertically upward and then rotates while remaining stationary in the vertical direction. After a complete rotation, the OUI 125 stops rotating and moves vertically upward by a predetermined step length or height again. This sequence of step-by-step vertical and rotational movement is repeated until the entire height of the OUI 125 is scanned. When the OUI 125 needs to move very slowly so as not to damage the contents, a step-by-step sequence of vertical and rotational movement is desirable. Thereafter, the OUI 125 moves downward along a vertical trajectory or along a stepwise vertical trajectory (without any rotational movement).

[0100] As the OUI 125 rises, it passes through a horizontal fan beam 130 of pulsed high energy X-rays at step 510. The beam 130 of X-rays is emitted from an X-ray source 118 positioned at an elevation on one side of the OUI 125 as discussed earlier in this specification.

[0101] At step 512, the X-rays transmitted through the OUI 125 impinge on the detector array 120, which is configured to generate corresponding scan data. The scan data is processed by the computing device by applying a filtered back-projection algorithm to reconstruct a 3D image of the OUI 125 for display on a screen associated with the computing device.

[0102] At step 514, once the entire height of the OUI 125 is scanned, the source 118 is turned off and the OUI 125 is lowered by the platform or table 115 to subsequently allow the conveyor 112 to move the scanned OUI 125 through the now open exit screen door 110. In parallel with the unloading process of step 514, another object is loaded into the enclosure 101 to maximize throughput. In some embodiments, the platform or table 115 continues to rotate and translate vertically downward. In some embodiments, the platform or table 115 stops rotating while translating vertically downward.

[0103] In a second embodiment, higher throughput can be achieved by modifying the method 500 to capture scanned images without rotating the OUI 125. That is, the platform or table 115 is configured to only translate the OUI 125 vertically upward for scanning (without rotation). In this embodiment, the vertical upward movement of the OUI 125 can be performed at a much faster pace, with scan times on the order of seconds rather than minutes.

[0104] In a third embodiment, scan data is captured at multiple discrete angles. In this way, an object can be scanned at, say, 30 degrees during vertical upward lift (the angular rotation can vary in various embodiments), and then rotated another 30 degrees while at a certain height before being scanned while being lowered. This provides a scan time and throughput somewhere between the first and second embodiments described above, and a corresponding detection capability somewhere in between.

[0105] The above examples are merely illustrations of many applications of the systems and methods of this specification. Although only a few embodiments of the present invention are described herein, it should be understood that the present invention may be implemented in many other specific forms without departing from the spirit or scope of the present invention. Therefore, the present examples and embodiments are considered to be illustrative rather than restrictive, and the present invention may be modified within the scope of the appended claims.

Claims

1. A system for inspecting an object, comprising: X-ray radiation source; a horizontal detector array, wherein said source and said detector array are disposed substantially in a first plane; a platform configured to rotate and configured to translate along a vertical trajectory, wherein the platform is disposed in a second plane between the source and the detector array, and wherein the platform is adapted to receive and support the object; as well as A computing device configured to: causing the source to emit a substantially horizontal fan-shaped X-ray beam in a third plane, wherein the third plane is above a top of the object; acquiring calibration data from the detector array when the third plane is above the top of the object; causing the platform to simultaneously rotate and vertically raise the object; acquiring scan data of the object; and A three-dimensional scan image of the object is generated using the calibration and scan data.

2. The system according to claim 1, wherein: The objects are densely packed unit load devices or pallets.

3. The system according to claim 1, wherein: The source is a LINAC or betatron configured to operate at energies ranging from approximately 750 keV up to 10 MeV.

4. The system according to claim 1, wherein: The source has a dose output in the range of 0.01 Gy / min to 30 Gy / min.

5. The system according to claim 1, wherein: The source includes a secondary collimator configured to generate the horizontal fan-shaped X-ray beam.

6. The system according to claim 1, wherein: The detector array is 1 to 6 channels or pixels high.

7. The system according to claim 1, wherein: The detector array is 8 to 12 channels or pixels high.

8. The system according to claim 1, wherein: The detector array has from 1 to 20 channels or pixels.

9. The system according to claim 1, wherein: The system has a magnification of approximately 1.525 and a reconstruction resolution of approximately 22 mm per slice.

10. The system of claim 1, wherein the system has a throughput of at least 5 units per hour.

11. The system according to claim 1, wherein: The platform includes a first drive mechanism configured to rotate the object at a first rotational speed and a second drive mechanism configured to rotate the object at a second rotational speed.

12. The system according to claim 11, wherein: The first rotation speed ranges from about 5 minutes per revolution to 30 seconds per revolution, and wherein the second speed ranges from about 30 seconds per revolution to 0.5 seconds per revolution.

13. The system according to claim 11, wherein: The platform also includes a screw lift / scissor lift to raise or lower the object.

14. The system according to claim 11, wherein: The platform also includes a lift that is raised and lowered by a piston assembly to raise or lower the object.

15. A method of inspecting an object using a platform positioned between a source of X-ray radiation and a horizontal detector array, the method comprising: transporting the object on a conveyor to place the object on the platform; triggering the source to emit a horizontally diverging fan beam, wherein a plane of the fan beam is above a top surface of the object; acquiring calibration data using the detector array; rotating the platform and raising it vertically upward so that the object moves in a substantially spiral trajectory; acquiring scanning data by exposing the moving object to the fan beam; as well as A three-dimensional scan image of the object is generated using the calibration and scan data.

16. The method according to claim 15, wherein: The objects are densely packed unit load devices or pallets.

17. The method according to claim 15, wherein: The source is a LINAC or betatron configured to operate at energies ranging from approximately 750 keV up to 10 MeV.

18. The method according to claim 15, wherein: The source has a dose output in the range of 0.01 Gy / min to 30 Gy / min.

19. The method according to claim 15, wherein: The source comprises a secondary collimator configured to generate the horizontal fan-shaped X-ray beam.

20. The method according to claim 15, wherein: The detector array is 1 to 6 channels or pixels high.

21. The method according to claim 15, wherein: The detector array is 8 to 12 channels or pixels high.

22. The method according to claim 15, wherein: The detector array has from 1 to 20 channels or pixels.

23. The method according to claim 15, wherein: The method is able to achieve a magnification of approximately 1.525 and a reconstruction resolution of approximately 22 mm per slice.

24. The method according to claim 15, wherein: The method is capable of having a throughput of at least 5 units per hour.

25. The method of claim 15, wherein: The platform includes a first drive mechanism configured to rotate the object at a first rotational speed and a second drive mechanism configured to rotate the object at a second rotational speed.

26. The method according to claim 25, wherein: The first rotation speed ranges from about 5 minutes per revolution to 30 seconds per revolution, and wherein the second speed ranges from about 30 seconds per revolution to 0.5 seconds per revolution.

27. The method according to claim 25, wherein: The platform also includes a screw lift / scissor lift to raise or lower the object.

28. The method according to claim 25, wherein: The platform also includes a lift that is raised and lowered by a piston assembly to raise or lower the object.

29. The method of claim 15, further comprising: When the entire height of the object has been scanned, moving the platform vertically downward; as well as The object is transported away from the platform while another object is conveyed toward the platform.

30. A system for inspecting an object, comprising: X-ray radiation source; a horizontal detector array, wherein the source and the detector array are disposed substantially in a first plane, and wherein the detector array comprises channels or pixels ranging from 1 to 20; a platform configured to rotate and translate along a vertical trajectory, wherein the platform is disposed in a second plane between the source and the detector array, and wherein the object is disposed on the platform; as well as A computing device configured to: causing the source to emit a substantially horizontal fan-shaped X-ray beam in a third plane, wherein the third plane is above a top of the object; acquiring calibration data from the detector array when the third plane is above the top of the object; causing the platform to simultaneously rotate and vertically raise the object; Acquiring scan data of the object; using the calibration and scanning data to generate a three-dimensional scan image of the object; and Once the entire height of the object has been illuminated by the fan beam, the stage is moved vertically down to the second plane.

31. The system of claim 30, wherein: The objects are densely packed unit load devices or pallets.

32. The system of claim 30, wherein: The platform does not rotate when moving vertically downward.

33. The system of claim 30, wherein: The platform continues to rotate while moving vertically downward.

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