Determination of structural integrity using penetrating radiation

Abstract

A method, and a corresponding system, for determining structural integrity of a target object using penetrating radiation such as X-rays are provided. The method includes (i) scanning a beam of the penetrating radiation over the target object in a pattern and (ii) detecting scattered radiation that is scattered from the target object, as a function of position of the beam of the penetrating radiation in the pattern, so as to generate a scatter intensity profile of the target object over the pattern. The method further includes (iii) determining structural integrity of the target object based on the scatter intensity profile.

Description

Attorney Docket: 20098.0054WOU1Determination of Structural Integrity Using Penetrating RadiationRELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 779,758, filed on March 28, 2025. The foregoing application is hereby incorporated herein by reference in its entirety.TECHNICAL FIELD

[0002] The present invention relates to determination of structural integrity of target objects, and more particularly to doing so using penetrating radiation.BACKGROUND

[0003] Transmission imaging is the most common modality’ for performing X-ray imaging and involves placing a source of X-rays on one side of the target object being imaged while measuring the intensity of X-rays transmitted through the object as measured by an X-ray detector placed on the other side of the object. Transmission imaging is therefore indicative of how many X-rays get absorbed at each point via any interaction process in the object that removes X-rays from the incident beam. These interactions include photo absorption, coherent scattering (Thompson scatter), and incoherent Compton scatter. For example, medical X-ray imaging involves imaging bones and organs, which appear dark in dense regions where many X-rays are absorbed, such as bones. (It should be noted, however, that in the medical field X-rays are often displayed as a negative image for clarity, with bones showing up as bright regions).

[0004] Backscatter imaging, in which X-rays scattered by a material in a direction directed generally backward toward the source of radiation employed, offers several unique inspection capabilities and operational features known in the art. For example, because the scatter signal falls off quite rapidly with increasing depth into the object, backscatter images effectively represent a “slice” of the object characteristic of the side nearest to the X-ray source; this image is frequently useful even when a transmission image representing the same scanned area is confused by image clutter, as a transmission image shows all features within a scanned area equally, regardless of depth in the object.

[0005] The underlying physical phenomenon that leads to scattered radiation is the Compton effect. Low atomic number (low Z) materials, which encompass organic materials, interact with X-rays principally by Compton scattering. Narcotic drugs, being among the densest of organic materials, tend to produce the brightest signatures in a backscatter image, as do organic explosives, making backscatter imaging a useful imaging modality' for bomb or drug detection.SUMMARY

[0006] X-ray radiography applied to the non-invasive inspection of surfaces concealed under insulation or other materials is a mature technology earned out by a wide variety7of methods. For example, the inspection of pipes that are insulated or otherwise covered is typically performed with transmission X-ray radiography using an electronic X-ray source or a radioactive isotopic source, combined with a high-resolution detector panel or a line array of segmented detectors. The disadvantage of this approach is that they use fan or cone beams of radiation, subjecting the operator to high levels of radiation. They also require the operator to position and support the line detector or detector panel on the far side of the pipe, opposite the radiation source. This is often slow and cumbersome and often not possible due to surrounding clutter around the pipe.

[0007] Practically speaking, transmission imaging only detects corrosion which is on the pipe “horizon”, where it will appear as an irregularity7on what is otherwise the straight edge of the pipe. This means that in other areas of the pipe, the corrosion will not be detected, unless imaging is performed from many different angles around the circumference of the pipe. Once again, this is time-consuming and may not be possible due to space limitations.

[0008] Backscatter X-ray radiography systems typically use an X-ray source and a rotating chopper wheel with apertures to create a sweeping pencil beam of X-rays that scans the target object under inspection. Backscatter detectors detect X-rays scattered back from the target object, and a transmission detector may also optionally be used to detect the X-rays from the pencil beam that are transmitted through the object at the same time as the scattered X-rays are detected.

[0009] More recently, with the development of handheld X-ray backscatter imagers that operate at X-ray energies of between 120 keV and 160 keV, for example, the possibility of detecting corrosion under insulation (CUI) using X-ray backscatter hasbecome possible. X-ray backscater imaging has several advantages, including very low radiation dose to the operator as the method uses a pencil beam of radiation, rather than the much more intense fan beams or cone beams used in traditional transmission radiography. Additionally, no placement of a transmission detector on the far side of the pipe is required, allowing single-sided inspection of pipes to be performed in environments where transmission imaging is not possible. Since placement of a separate detector is not required, inspection times can also be greatly reduced.

[0010] Another significant advantage of scater imaging for CUI inspection is that corrosion on all parts of the pipe surface can be detected in a scater image, rather than only on the pipe “horizon,” as in transmission imaging. This means that far fewer images need to be acquired to inspect an entire surface of the pipe.

[0011] One of the disadvantages of scatter imaging for pipe CUI inspection, however, is that the corrosion often appears with very low contrast in the scater images, making it difficult to detect CUI reliably or to correctly interpret the images. Methods are therefore needed for reliably detecting CUI in X-ray scater images and to allow for automated detection and alerting an operator to a presence of CUI.

[0012] Given the considerations above, various specific embodiments of the invention include the following.

[0013] In accordance with a first specific embodiment of the invention, a method for determining structural integrity of a target object using penetrating radiation includes:a. scanning a beam of the penetrating radiation over the target object in a patern;b. detecting scatered radiation that is scatered from the target object as a function of position of the beam of the penetrating radiation in the patern so as to generate a scatter intensity profile of the target object over the patern; andc. determining structural integrity of the target object based on the scater intensity7profile.

[0014] In accordance with a second specific embodiment of the invention, a system for determining structural integrity of a target object using penetrating radiation includes:a. a penetrating radiation scanning module configured to output a scanning beam of the penetrating radiation over the target object in a pattern;b. a scater radiation detector configured to detect scatered radiation that is scatered from the target object as a function of position of the scanning beam of the penetrating radiation in the patern so as to generate a scater intensity profile of the target object over the pattern; andc. a structural integrity determination module configured to output an indication of structural integrity7of the target object based on the scater intensity profile.

[0015] In accordance with a third specific embodiment of the invention, a system for determining structural integrity of a target object using penetrating radiation includes:a. means for scanning a beam of the penetrating radiation over the target object in a pattern;b. means for detecting scatered radiation that is scatered from the target object as a function of position of the beam of the penetrating radiation in the patern so as to generate a scater intensity7profile of the target object over the patern; andc. means for determining structural integrity of the target object based on the scater intensity' profile.

[0016] Other embodiments and implementations thereof wi 11 become apparent to those of ordinary skill in the art of radiation scanning in reference to the examples provided in the drawings and description.BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The foregoing features of embodiments will be more readily understood by reference to the following detailed description, taken with reference to the accompanying drawings. A brief description of the drawings follows.

[0018] FIG. 1 (prior art) is a perspective-view diagram illustrating an example X-ray imaging system for luggage.

[0019] FIG. 2 (prior art) is an illustration of an existing handheld X-ray imaging system incorporating a disk chopper wheel assembly.

[0020] FIG. 3 (prior art) is a perspective-view illustration of a target inspection system that includes a handheld portable X-ray imaging system, a coupling arm that includes multiple adjustable joints and a transmission detector module that is rotatablycoupled to the coupling arm and is rotatable for selection of resolution of a transmission image.

[0021] FIG. 4 is a cross-sectional diagram illustrating a positioning of a handheld X-ray imaging system against a wall of an insulated pipe, according to one implementation, for a determination of structural integrity, such as whether corrosion is present.

[0022] FIG. 5A is a computer generated, simulated X-ray backscatter image of a clean, corrosion-free pipe phantom, with 1” of mineral wool insulation, with the X-ray imager in translation mode.

[0023] FIG. 5B is a computer generated, simulated X-ray backscatter image of the pipe phantom used for FIG. 5A, but with the X-ray imager in stationary mode.

[0024] FIG. 5C is a graph, illustrating a scatter intensity profile, generated based on the detector data used for the stationary mode image of FIG. 5B.

[0025] FIG. 6A is a computer generated, simulated X-ray backscatter image of a pipe phantom with a 1 / 8” deep rust-filled depression, encased in 1” of mineral wool insulation, with the X-ray imager in translation mode.

[0026] FIG. 6B is a computer generated, simulated X-ray backscatter image of a pipe phantom used for FIG. 6A, but with the X-ray imager in stationary mode.

[0027] FIG. 6C is a graph, illustrating a scatter intensity profile, generated based on the detector data used for the stationary mode image of FIG. 6B.

[0028] FIG. 7A is a computer generated, simulated X-ray backscatter image of a pipe phantom with a 1 / 8” deep rust-filled depression, encased in 3” of mineral wool insulation, with the X-ray imager in translation mode.

[0029] FIG. 7B is a computer generated, simulated X-ray backscatter image of a pipe phantom used for FIG. 7A, but with the X-ray imager in stationary mode.

[0030] FIG. 7C is a graph, illustrating a scatter intensity profile, generated based on the detector data used for the stationary mode image of FIG. 7B.

[0031] FIG. 8 A is a computer generated, simulated X-ray backscatter image of a pipe phantom with a 1 / 8” deep corrosion pit, encased in 1” of mineral wool insulation, with the X-ray imager in translation mode.

[0032] FIG. 8B is a computer generated, simulated X-ray backscatter image of a pipe phantom used for FIG. 8A, but with the X-ray imager in stationary mode.

[0033] FIG. 8C is a graph, illustrating a scatter intensity7profile, generated based on the detector data used for the stationary mode image of FIG. 8B.

[0034] FIG. 9A is a graph, illustrating a scatter intensity7profile, similar to that of FIGs. 5C, 6C, 7C, and 8C. but with a 1 / 8"’ deep air cavity.

[0035] FIG. 9B is a graph, illustrating a scatter intensity profile, similar to that of FIGs. 5C, 6C, 7C, and 8C, but with a 1 / 4” deep air cavity.

[0036] FIG. 10A is a graph, illustrating a scatter intensity' profile, similar to that of FIGs. 5C, 6C, 7C, and 8C, but with a 1 / 8” high rust deposit.

[0037] FIG. 10B is a graph, illustrating a scatter intensity profile, similar to that of FIGs. 5C, 6C, 7C, and 8C, but with a 1 / 4” high rust deposit.

[0038] FIG. 11 A is a picture of a real 4” pipe used for testing, including a series of dimple irregularities on a surface thereof, the pipe having a l” thick insulation during testing but having the insulation removed from the pipe for clarity in the picture.

[0039] FIG. 1 IB is a graph illustrating a scatter intensity profile along a length of the pipe of FIG 11 A, with the insulation in place, acquired with a 160keV Raven™ handheld backscatter X-ray imager manufactured by Viken Detection®.

[0040] FIG. 11 C is a graph illustrating a scatter intensity profile along a length of clean, corrosion free pipe.

[0041] FIG. 12A is a picture of the pipe used for testing, also shown in FIG HA, but reoriented in FIG 12A for an understanding of cross-wise scans.

[0042] FIG. 12B is a graph illustrating a scatter intensity profile across a length of the pipe of FIG 12A covering a surface irregularity including a 1 / 8” dimple . with the insulation in place during the scan, acquired with a 160keV Raven™ handheld backscatter X-ray imager manufactured by Viken Detection®.

[0043] FIG. 12C similar that of FIG. 12B, but covering a surface irregularity' including a 3 / 8” dimple.

[0044] FIG. 12D similar that of FIG. 12B, but with a clean surface of the pipe with no irregularity’.

[0045] FIG. 12E similar that of FIG. 12B, but covering a surface irregularity' including a 1 / 4” dimple.

[0046] FIG. 12F similar that of FIG. 12B. but covering a surface irregularity including a 3 / 16” dimple.

[0047] FIG. 13 is a flow chart illustrating elements of a procedure for determining a structural integrity of a pipe consistent with an implementation of an embodiment, including fitting a polynomial function.

[0048] FIG. 14 is a flowchart illustrating elements of a procedure for determining a structural integrity of a pipe consistent with an implementation of an embodiment, including matching a scatter intensity profile to a template.

[0049] FIG. 15 is a flowchart illustrating elements of a procedure for determining a structural integrity of a pipe consistent with an implementation of an embodiment, including reflecting a scatter intensity profile about an axis of symmetry.

[0050] FIG. 16 is a graph illustrating a scatter intensity profile for a cross-wise scan of a pipe, with a parabolic curve fit to a portion of the profile, consistent with the procedure illustrated in FIG. 13.

[0051] FIG. 17A is a graph showing a scatter intensity profile for a cross-wise X-ray scan of a clean, irregularity -free pipe having two sides and an axis of substantial symmetry between them.

[0052] FIG. 17B is a copy of the left side of the graph of FIG. 17A, with the right side reflected about the axis of substantial symmetry and overlaid onto the left side, consistent with the procedure illustrated in FIG. 15.

[0053] FIG. 18A is a graph showing a scatter intensity profile of a corroded pipe.

[0054] FIG. 18B is a graph showing the reflection of the right side of the detected scatter profile about the axis of symmetry onto the left side of the detected scatter profile and the identification of a subregion where the two profiles significantly differ from one another, corresponding to the embodiment shown in FIG. 15.

[0055] FIG. 19 is a graph showing a portion of the scatter intensity profile of FIG.18B (upper curves) and also showing calculated chi-square values (lower curve), consistent with the procedure illustrated in FIG, 15.

[0056] FIG. 20 is a perspective-view diagram of a scanning system using an elliptical pattern in which an incident X-ray scanning beam scans in a circular or other elliptical pattern across a surface of an insulated pipe.

[0057] FIG. 21 A is a graph illustrating a scatter intensity profile obtained using the elliptical scanning arrangement of FIG. 20, with no surface irregularities present on the Pipe.

[0058] FIG. 21B is a graph illustrating a similar scatter intensity profile of FIG. 21 A, but with a ‘Zi” hemispherical shaped irregularity present on a surface of the pipe,

[0059] FIG. 22 is a flow chart illustrating a procedure for determining structural integrity of a target object according to an embodiment.

[0060] FIG. 23 is a flow chart illustrating a procedure for determining structural integrity of a target object, according to an implementation of the procedure of FIG. 22 involving fitting a mathematical function to a scatter intensity profile.

[0061] FIG. 24 is a flow chart of a procedure 2400 for determining structural integrity of a target object.

[0062] FIG. 25 is a flow chart of a procedure 2500 for determining structural integrity of a target object.

[0063] FIG. 26 includes a schematic diagram illustrating a system for determining structural integrity of a target obj ect according to an embodiment.

[0064] FIG. 27 is a graph showing one representation of an example scatter intensity profile used to determine structural integrity of a target object according to FIG. 26.

[0065] FIG. 28 is a cross-sectional diagram illustrating a positioning of a handheld X-ray imaging system against a wall of an insulated tank, according to one implementation, for a determination of structural integrity of the tank, such as whether corrosion is present.DETAILED DESCRIPTION

[0066] General Considerations

[0067] The figures and descriptions provided herein may have been simplified to illustrate aspects that are relevant for a clear understanding of the herein described devices, systems, and methods, while eliminating, for the purpose of clarity, other aspects that may be found in typical similar devices, systems, and methods. Those of ordinary skill may recognize that other elements and / or operations may be desirable and / or necessary to implement the devices, systems, and methods described herein. However, because such elements and operations are well known in the art, and because they do not facilitate a better understanding of the present disclosure, a description of such elements and operations may not be provided herein. However, the present disclosure is deemed to inherently include all such elements, variations, and modifications to the described aspects that would be known to those of ordinary skill in the art.

[0068] The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. For example, as used herein, the singular forms '‘a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,”“comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order described or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0069] Although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. That is, terms such as “first,” “second,” and other numerical terms, when used herein, do not imply a sequence or order unless clearly indicated by the context.

[0070] Definitions

[0071] As used in this description and the accompanying claims, the following terms shall have the meanings indicated, unless the context otherwise requires:

[0072] “Set.” A “set” includes at least one member.

[0073] “Image.” As used in this description and in the appended claims, the term “image” refers to an ordered representation of detector signals, or processed detector signals, corresponding to spatial positions. For example, the image may be an array of values within an electronic memory, or, alternatively, a visual image may be formed on a display device such as a video screen or printer.

[0074] Use of algorithms, as known in the art of X-ray inspection for identifying suspect regions wi thin an enclosure, can be optionally included within the scope of the present disclosure. Identification of a presence of a specified condition, such as an irregularity (anomaly) on a surface of a target object, by means of an alarm or otherwise, is also within the scope of the present disclosure. When so specified, an image uses backscattered radiation as a key to the spatial distribution of the scattering material.

[0075] Elements Helpful for a Fuller Understanding of Scope of Embodiments and Implementations Thereof

[0076] Referring to FIG. 1 (prior art), a perspective-view diagram is provided, illustrating an existing example X-ray imaging system for luggage. An X-ray imaging system 100 of FIG. 1 exemplifies some basic features of known backscatter imaging systems that output a scanning (sweeping) pencil beam 108 of the source X-rays 104. An X-ray source 102 in this system is a standard X-ray tube, which generates the source X-rays 104. The source X-rays 104 are formed (here, collimated) into a stationary fan beam 106 by a collimation slit aperture in an attenuating plate 107. The stationary fan beam 539 can then be “chopped’7into a scanning pencil beam 108 by a disk chopper wheel 110 that defines scanning slit apertures 124 (which may also be referred to herein as “slits”) therein and rotates with a rotation 114. Together, the X-ray source 102, the attenuating plate 107, and the disk chopper wheel 110 form an X-ray beam-forming module 558. In alternative implementations, the source X-rays 104 are formed only into the stationary fan beam 106, which is used to scan over the target directly, without a need for the disk chopper wheel 110.

[0077] The scanning pencil beam 108 thus scans over an article of luggage 120 as the article of luggage 120 moves with the relative motion 124 (travel direction) between the article of luggage 120 and the X-ray source 102. The article of luggage 120 is an example of a target object to be inspected. The relative motion 124 in this diagram is provided by a conveyor 122, which includes a table and a conveyor belt that moves the article of luggage 120 with respect to the source 102.

[0078] The X-ray scanning system 100 can perform transmission X-ray imaging using a transmission X-ray detector 150. X-rays of the scanning pencil beam 108 that interact with the article of luggage 120 (in this case by being transmitted through the article of luggage 120) are detected by the transmission X-ray detector 150. The transmission X-ray detector 150 outputs a detector signal to a monitor 130 via a detector signal cable 128, and the monitor 130 shows a transmission X-ray image 132 of contents of the article of luggage 120. Multiple X-ray scanning pencil beams 108 may form a scan line pattern 160.

[0079] The X-ray imaging system 100 can also perform backscatter X-ray imaging using a set of backscatter-imaging X-ray detectors (not shown in FIG. 1). The backscatter imaging X-ray detectors may be positioned to detect resultant X-rays that result from the scanning pencil beam 108 interacting with the article of luggage 120 and are scattered by the article of luggage 120 in a general or specific backw ard direction, such as in a vicinitybetween the article of luggage 120 and the disk chopper wheel 110. An intensity of the resultant X-rays scattered in the backwards direction may be thus recorded by the set of more backscatter X-ray backscatter detectors (not shown in FIG. 1) as a function of position of the irradiating, scanning pencil beam 108. In the case of backscatter X-ray imaging, it can be advantageous for the backscatter X-ray detectors to be large-area detectors in order to detect the greatest number of X-rays scattered in various specific backward directions. By moving the article of luggage 120 through a scan plane of the pencil scanning beam 108, either on the conveyor 122 or under its own power, a two-dimensional backscatter image of the article of luggage 120 may be obtained.

[0080] Referring to FIG. 2 (prior art), with further reference to FIG. 1, an illustration is provided showing an existing handheld X-ray imaging system 200 that incorporates an X-ray beam-forming module, similar to the X-ray beam-forming module 158 of FIG. 1, with a disk chopper wheel. Components of the handheld X-ray imaging system 200, such as an X-ray tube and a disk chopper w heel, are mounted within a housing 234 of the handheld X-ray imaging system 200. As part of handheld use, the X-ray imaging system 200 can be carried and moved by a person via handles 236 to scan a vehicle, luggage, or other target flexibly to detect contraband, safety’ issues, etc.

[0081] As illustrated in FIG. 2, a hand 238 of a person holds the X-ray imaging system 200, in this example via handles 236. The X-ray imaging system 200 is pointed such that a scanning X-ray pencil beam (not illustrated in FIG. 2) is output from the X-ray imaging system 200 during operation and directed toward a vehicle wheel 220. The vehicle wheel 220 is an example of a target (which may also be referred to herein as a “target object,” which can be X-ray scanned for contraband. The X-ray imaging system 200 is configured to produce a real-time image 232 of the vehicle wheel 220, displayed on a screen 398.

[0082] Referring to FIG. 3 (prior art), with further reference to FIGs. 1-2, a perspective-view' illustration is provided for a target inspection system that includes a handheld portable X-ray imaging system 300. The system 300 may also be referred to herein as a “scanner” 300 or “imager” 300. A sweeping X-ray pencil beam 308 is used as part of providing an image of a target object at a screen 398 for an operator to view. For scatter-based X-ray imaging, a scatter X-ray detector 340 is provided to detect X-rays backscattered from a target object (not show n in FIG. 3).

[0083] A coupling arm 350 is included, which has multiple adjustable joints, and an X-ray transmission detector arm 342 module is rotatably coupled to the coupling arm and is rotatable for selection of resolution of a transmission image. The X-ray transmission detector arm 342 in FIG. 3 is attached to the front end of the imager 300 via the coupling arm 350 at only one end in an open-geometry configuration, allowing the object (target, or target object) being scanned to be easily positioned between the imager and the detector as the imager 300 is moved relative to the object during the acquisition of the image. In one implementation, the position of the detector arm that is intercepting the sweeping X-ray beam transmitted through the object can be adjusted relative to the imager at one or more adjustable joints on the coupling arm, allowing smaller or larger objects to be imaged, or to allow objects such as car tires or doors to be imaged. In some applications, it can be advantageous to be able to position the detector arm at an angle with respect to the front face of the X-ray imaging system 300.

[0084] The system 300 shown in FIG. 3 has three adjustable joints on the coupling arm, allowing the detector arm to be aligned with the incident beam, as w ell as providing enough space between the detector arm 350 and the front of the imager to contain the object being scanned. The coupling arm can be rapidly connected to the X-ray imager 300 via a snap-connection that can provide both mechanical and electrical coupling. Rapid attachability and detachability via connection points such as the snap-connection may be provided on both sides of the X-ray imager 300 as shown in FIG. 3, allowing an operator more flexibility when imaging.

[0085] In some implementations, the X-ray transmission detector arm 350 contains a strip of scintillator (such as scintillating phosphor), and the scintillation light is collected using wavelength-shifting fibers (WSFs). At least one end of the fibers may be coupled to at least one photodetector, such as a photomultiplier tube (PMT). Alternative implementations can use scintillator rods that act as light guides, or hollow' light guides lined w'ith reflective material that direct the scintillation light from an enclosed scintillator to photodetectors at one or more ends of the lightguide.

[0086] The X-ray transmission detector arm 350 may be a single-energy detector that produces black and white transmission images. Alternatively, the X-ray transmission detector arm 350 may be a dual-energy detector that provides material identification and from which colorized transmission images may be generated. The X-ray transmission detector arm 350 may be a standard sandwich-type detector that requires two or morestacked scintillator volumes. Alternatively, the X-ray transmission detector arm 350 can provide for dual-energy detection by incorporating a single volume of scintillator optically coupled to two layers of WSFs.

[0087] In implementations, the X-ray transmission detector arm 350 may include one or more lasers mounted on the X-ray imaging system to assist in aligning the active input region of the X-ray transmission detector arm 350 with the incident sweeping beam. The illumination spots of the lasers at each end of the X-ray transmission detector arm 350 may be used to provide feedback cues for adjusting the coupling arm to provide optimal alignment of the beam with the scintillator volume. In other implementations, fiducial markers that are visible in the transmission X-ray image itself are incorporated. The fiducial markers may provide information on a quality of the beam alignment when acquiring a particular X-ray image.

[0088] In implementations, the X-ray transmission detector arm 350 may have at least one spring-loaded coupling that provides some shock protection should the detector strike an object or get stuck when performing a scan. In implementations, a transmission detector kit may be included, and the kit may include detector arms of different lengths and which can be advantageously used to scan objects under various conditions and with differing accessibility challenges.

[0089] In implementations, the X-ray transmission detector arm 350 may provide variable resolution along the scan direction (i.e. the direction of relative motion of the imager with respect to the object). The width of the scintillator strip intercepting the transmitted beam determines the maximum width of the beam that is detected and contributes to the image. Therefore, the width of the scintillator strip determines the resolution of the transmission image in the scan direction. If the width of the scintillator strip perpendicular to the incident beam direction is smaller than the width of the beam at the point where it intercepts the detector, then the image resolution will be defined by the perpendicular width of the scintillator, and not the width of the beam, resulting in higher resolution. If the scintillator strip is wider than the beam, then the image resolution is defined by the width of the beam, resulting in lower resolution. By rotating the X-ray transmission detector arm 350 relative to the incident beam (curved arrow in FIG. 3), the scintillator strip presents a varying width to the incident beam.

[0090] Features of Various Embodiments

[0091] Referring to FIG. 4, a cross-sectional diagram is provided, illustrating a positioning of a handheld X-ray imaging system against a wall of an insulated pipe, according to one implementation, for a determination of structural integrity, such as whether corrosion is present. The X-ray imaging system 400 may be employed consistent with embodiments. In some implementations, the X-ray imaging system 400 includes: handles 234, a disk chopper wheel 410, a focal spot 442, and a scatter X-ray detector 440. The X-ray imaging system includes an X-ray fan beam 120 that is emitted through the disk chopper wheel 410, which projects X-ray pencil beams 108 in a beam sweep direction 444 over a target object.

[0092] FIG. 4 also illustrates a pipe 420 to which the imaging system 400 is applied to determine the structural integrity of the pipe. The pipe 420 includes cladding 450, insulation 448. and a pipe surface 446. The pipe 420 is an example of a target object, which may also be referred to herein as simply a ‘'target.’’

[0093] The system 400 can be used consistent with embodiments to determine structural integrity of the pipe 420. The disk chopper wheel 410 forms part of a penetrating radiation scanning module, in this case an X-ray scanning module. The X-ray scanning module also includes an X-ray source (not show n in FIG. 4) that outputs the X-ray fan beam 120. The X-ray fan beam 120 and the disk chopper wheel 410, working in concert, generate the X-ray pencil beam 108 that scans over the pipe 420 in a pattern. The pattern may be a line scan pattern, similar to that shown in FIG. 1, or another type of pattern. As X-ray radiation is scattered from the pipe 420, it is detected by the scatter X-ray detector 440. A scatter intensity profile of the pipe 420 is thus generated, which includes at least measures of scatter intensity for various positions on the pipe target that are intersected by the X-ray pencil beam 108 to form the pattern. Scatter intensity profiles may optionally be represented graphically, as described hereinafter in connection with later figures.

[0094] The X-ray imaging system 400 can include a structural integrity determination module (not shown in FIG. 4) that is configured to output an indication of structural integrity of the pipe 420 based on the scatter intensity profile. The structural integrity determination module can include a set of computer processors, a software module being run by the set of computer processors, embedded firmware, and / or electronics running embedded firmw are, for example. In one example, the structural integrity determination module is included within an enclosure (housing) of the X-ray imaging system 400.However, in alternative examples, the structural integrity determination module is outside of the X-ray imaging system 400. In either case, the structural integrity determination module can be communicatively coupled with the scatter X-ray detector 440 to receive the scatter intensity profile data and to process these data to determine structural integrity. Structural integrity can include, for example, an indication of whether the pipe 420 has corrosion or other anomalies indicative of decay, damage, etc.

[0095] Referring to FIGs. 5-12, with further reference to FIGs. 1-4, several examples of simulated backscatter images and scatter intensity profiles that correspond with a variety7of target objects are provided.

[0096] A backscatter image, as exemplified in FIGs. 5A and 5B, is a visual depiction of detected backscatter radiation. This backscatter image is obtained by an X-ray imaging system, such as the X-ray imaging system 400 that is described in FIG. 4. Backscatter images can be generated in translation mode or in stationary mode. Translation mode typically includes relative motion between an X-ray imaging system and a target object to obtain an X-ray image of a two-dimensional portion of a target object. In contrast, in stationary mode, the X-ray imaging system and the target object may be stationary in respect to one another.

[0097] A scatter intensity profile may be generated corresponding to the backscatter images, whether in translational mode or stationary mode. In an implementation, scatter intensity profiles may be depicted in graphical form, plotting detected scatter intensity as a function of position. In one example, the scatter intensity may be a "gray value” as a function of position. Position (also referred to herein as “distance”) may be given in units of scatter detector pixels or other units across a scan, for example.

[0098] On the scatter intensity profile graphs of the subsequent figures, a “valley” can indicate an irregularity consistent with material having been removed (such as a hole) being formed) from a target object (such as a pipe). A valley can appear because scattered X-rays may be somewhat confined by a depressed area. Conversely, a “peak” in the scatter intensity profile can indicate an irregularity such as a deposit or buildup on the target object, such as a rust deposit on a pipe. A peak may appear where the scattered X-rays are received in greater number from a particular position of the target object compared with surrounding positions.

[0099] Referring to FIGs. 5A-5C, with further reference to FIGs. 1-4, examples of a simulated, computer-generated backscatter image of a target object and a graph of itscorresponding scatter intensity profile for a corrosion free pipe phantom with 1” of mineral wool insulation, are provided. FIG. 5A illustrates a backscatter image acquired with a handheld X-ray imager in translation mode. FIG. 5B is a computer generated, simulated X-ray backscatter image of the pipe phantom used for FIG. 5 A, but with the X-ray imager in stationary mode. When an X-ray imager scans, the imager may obtain horizontal scans that are stacked vertically to form a two-dimensional backscatter image. FIG. 5C is a graph, illustrating a scatter intensity profile, generated based on the detector data used for the stationary mode image of FIG. 5B. The scatter intensity profile 572 of FIG. 5C does not show any major peaks or valleys, which is consistent with a target object having no surface irregularities. In this example, gray value on the vertical axis is a sum of all pixel values from the received backscatter at the target location corresponding to that position on the graph.

[0100] Referring to FIGs. 6A-6C, examples of simulated, computer-generated backscatter images of a pipe phantom with a 1 / 8” deep rust-filled depression, with 1” of mineral wool insulation, and its corresponding scatter intensity profile, are provided. FIG.6A illustrates a backscatter image acquired with a handheld X-ray imager in translation mode. FIG. 6B illustrates a computer generated, simulated X-ray backscatter image of a pipe phantom used for FIG. 6A, but with the X-ray imager in stationary mode. FIG. 6C is a graph, illustrating a scatter intensity profile 672, generated based on the detector data used for the stationary mode image of FIG. 6B. FIG. 6C illustrates a peak on the scatter intensity profile, which is consistent with a target object having a surface irregularity', such as a rust-filled depression.

[0101] Referring to FIGs. 7A-7C, examples of simulated, computer-generated backscatter images of a pipe phantom with a 1 / 8” deep rust-filled depression, with 3” of mineral wool insulation, and its corresponding scatter intensity profile, are provided. FIG.7A illustrates a backscatter image acquired with a handheld X-ray imager in translation mode. FIG. 7B illustrates a computer generated, simulated X-ray backscatter image of a pipe phantom used for FIG. 7A, but with the X-ray imager in stationary' mode. FIG. 7C is a graph, illustrating a scatter intensity profile 772, generated based on the detector data used for the stationary mode image of FIG. 7B. FIG. 7C illustrates a peak on the scatter intensity profile, which is consistent with a target object having a surface irregularity', such as a rust-filled depression.

[0102] Referring to FIGs. 8A-8C, examples of simulated, computer-generated backscatter images of a pipe phantom with a 1 / 8’" corrosion pit. with 1” of mineral wool insulation, and its corresponding scatter intensity profile, are provided. FIG. 8A illustrates a backscatter image acquired with a handheld X-ray imager in translation mode. FIG. 8B illustrates a computer generated, simulated X-ray backscatter image of a pipe phantom used for FIG. 8A, but with the X-ray imager in stationary mode. FIG. 8C is a graph, illustrating a scatter intensity’ profile 872, generated based on the detector data used for the stationary mode image of FIG. 8B. FIG. 8C illustrates a valley on the scatter intensity profile, which is consistent with a target object having a surface irregularity, such as a corrosion pit.

[0103] Referring to FIG. 9A, a graph, illustrating a scatter intensity profile 972a. similar to that of FIGs. 5C, 6C, 7C, and 8C. but with a 1 / 8” deep air cavity is provided. FIG. 9A illustrates a valley on the scatter intensity profile, consistent with the air cavity. In comparison, FIG. 9B is a graph, illustrating a scatter intensity profile 972b, similar to that of FIGs. 5C, 6C, 7C, and 8C, but with a 1 / 4” deep air cavity. FIG. 9B illustrates a valley on the scatter intensity profile, consistent with the air cavity. FIG. 9B illustrates a valley that is more pronounced than that of the valley in FIG. 9A, consistent with the air cavity being deeper.

[0104] Referring to FIG. 10A a graph, illustrating a scatter intensity profile 1072a, similar to that of FIGs. 5C, 6C, 7C, and 8C, but with a 1 / 8” high rust deposit, is provided. FIG. 9A illustrates a peak on the scatter intensity profile, consistent with a surface irregularity- of a target object, such as a rust deposit. In comparison, FIG. 10B is a graph, illustrating a scatter intensity profile 1072b, similar to that of FIGs. 5C, 6C, 7C, and 8C, but with a 1 / 4” high rust deposit. FIG. 10B illustrates a peak that is more pronounced than that of the peak in FIG. 10 A, consistent with the rust deposit being higher.

[0105] Referring to FIG. 11 A, a picture is provided of a real 4” pipe 1240 used for testing, which includes a series of dimple irregularities on a surface thereof, the pipe 1240 having a l” thick insulation during testing but having the insulation removed from the pipe for clarity in the picture. The series of dimples illustrate approximate depths into the surface of the pipe, from page left to page right, of 1 / 8”, 3 / 16”, 1 / 4", and 3 / 8”, wherein the last surface irregularity is a slit cut partially into the pipe wall. FIG. 1 IB is a graph illustrating a scatter intensity along a length of the pipe of FIG 11 A, with the insulation in place, acquired with a 160keV Raven™ handheld backscatter X-ray imager manufacturedby Viken Detection®. The graph illustrates valleys consistent with the dimples on the surface of pipe 1240, wherein the valley has a lower gray scale value corresponding with the depth of the dimple on the pipe 1240. In comparison, FIG. 11C is a graph illustrating a scatter intensity profile along a length of pipe 1240 in a location along the pipe 1240 consistent with a pipe 1240 having no surface irregularities along the length of the scan line.

[0106] Referring to FIG. 12A. a picture is provided of the same real 4" pipe 1240, as described in FIG. 11 A. The pipe 1240 is shown reoriented in FIG 12A for an understanding of cross-wise scans. FIGs. 12B, 12C, 12E, and 12F illustrate scatter intensity profiles for the dimples of various depths described in FIG 11 A, how ever, these scatter intensity profiles have been obtained by cross-wise scans. FIG. 12B is a graph illustrating a scatter intensity profile across a length of the pipe of FIG 12A covering a surface irregularity including a 1 / 8” dimple , with the insulation in place during the scan, acquired with a 160keV Raven™ handheld backscatter X-ray imager manufactured by Viken Detection®. FIG. 12C similar that of FIG. 12B, but covering a surface irregularity including a 3 / 8” dimple. FIG. 12D similar that of FIG. 12B, but the scan was taken along a length of pipe 1240 in a location along the pipe 1240 consistent with a pipe 1240 having no surface irregularities along the length of the scan line. FIG. 12E similar that of FIG.12B, but covering a surface irregularity including a 1 / 4” dimple. FIG. 12F similar that of FIG. 12B, but covering a surface irregularity including a 3 / 16” dimple.

[0107] FIG. 12 differs from FIG. 11 because the scans of FIGs. 12B-12F were taken across the width of the pipe (cross-wise), whereas the scans in FIGs. 1 IB and 11C were taken along the length of the pipe, which impacts the shape of the scatter intensity profile.

[0108] Referring to FIG. 13, a flow diagram depicting a procedure for determining structural integrity of a target object is shown. At a stage 1310. an X-ray imaging system a handheld X-ray imaging system, such as the system 400 in FIG. 4, is positioned against a pipe, such as the pipe 420 in FIG. 4. Positioning the X-ray imaging system against the pipe can provide a stable relative position between the system and the pipe, such that an acquired image may be reliably considered to be a stationary image.

[0109] At stage 1320a, a stationary backscatter image of the pipe is acquired. An example of the stationary backscatter image includes FIG. 5B. At a stage 1320b, a scatter intensity7profile is generated based on the acquired stationary7backscatter image, with pixel values summed as described in connection with FIGs. 5-12. The scatter intensityprofile, so generated, may be represented graphically as illustrated in FIG. 5C, for example.

[0110] At stage 1332, a parabolic a smooth parabolic curve is optimized for fit to the generated scatter intensity profile, as described in connection with FIG. 16, for example. At a stage 1334, chi square values of fit are calculated for each sub region of the scatter intensity profile. An example of a subregion is further described hereinafter in connection with a later figure. A subregion may include a running average of a given number of adjacent scattered intensities corresponding to adjacent pixels in the image, for example. In alternative implementations, a chi square value may be calculated for each pixel.[OHl] As known in the art, a chi-square distribution-ty pe error analysis may be used to test a fit of a function to a set of data and may be denoted by X2. Chi-square is one example measure of variance of the scatter intensity’ profile from the best fit mathematical function, which may be readily calculated for the present data as follows. Chi-square may be calculated by: X2= (( -E,)2 / Et . Here, each Ot is an “observed” scatter intensity’ at a given scan position i (e.g., as exemplified by the “gray value” at a particular distance in the scatter intensity profile of FIG. 5C; or as exemplified by the “grayscale value” at a given pixel position in the scatter intensity profile of FIG. 12X). Each Et is an “expected” value for scatter intensity at the given scan position i based on the best-fit mathematical function.

[0112] As will be understood by those skilled in the art of data analysis in view of this disclosure, each value of A2that is calculated may be based on a single scatter intensity data point, a set of scatter intensity7data points represented in a sub-region of a scatter intensity’ profile (such as a collection of data points for adjacent scan positions i (e.g. distances or pixels), or an entire scatter intensity profile. In this manner, relatively high values of chi-square, representing relatively high variances from the best-fit function for the given scatter intensity profile, can be indicators of a surface irregularity'. Further in view of this disclosure, those skilled in the art of data analysis will understand that besides chi-square, numerous other measures of variance may be used, and some w ill be more applicable to particular, respective types of mathematical functions that are being fit to a data set.

[0113] A threshold variance may be used to determine when a chi-square or other variance value represents a surface irregularity’. In one example, a threshold may be midway between average chi-square values observed for scans of clean pipes and averagechi-square values observed when a relatively smaller irregularity (e.g. 1 / 8’" dimple) is known to be present. Alternatively, the threshold may be 10%, 25%, 50%, or 75% greater than average chi-square values observed for scans of clean pipes, for example. Many other types of thresholds may be implemented, for example consistent with testing different ty pes of pipes or other target objects, or consistent with a particular X-ray scanning instrument or X-ray energy' used, and / or as a function of different respective types of variances potentially present in a scatter intensity’ profde (e.g. dimple, corrosive deposit, or hole).

[0114] In alternative implementations, a degree of fit between the best fit smooth parabolic curve and the data, may be calculated by alternative means as understood by those of ordinary skill in the art of scientific data analysis.

[0115] At a stage 1336, an alert is displayed to a user of the handheld X-ray imaging system if any of the chi square values is above a given threshold. An example of a given threshold is described hereinafter. The alert may be provided via a screen on the handheld X-ray imaging device, such as the screens 298, 398 illustrated in FIG. 3 and FIG. 3, respectively.

[0116] Referring to FIG. 14, a flow diagram depicting a procedure for determining structural integrity' of a target object is show n. The procedure illustrated in FIG. 14 includes stages 1310, 1320a, and 1320b previously illustrated and described in relation to FIG. 13.

[0117] The procedure of FIG. 14 further includes stages 1432, 1434 and 1436. At stage 1432, a best match scatter intensity profile is found to be compared to the scatter intensity’ profile generated in stage 1320b. The best match scatter intensity' profile template is chosen from a library' of templates. Each template may contain a curve based on the characteristics of the target object. In an example, a template may have a curve based on a 4” pipe with 1 " of insulation and no surface irregularities.

[0118] At stage 1434 a chi-square deviation of the generated scatter intensity profile 1320b from the template is calculated for each subregion of the scatter intensity’ profile. An example of the chi-square deviation is illustrated in a later figure. FIG. 19.

[0119] At stage 1436, similar to that of stage 1336 of FIG. 13, an alert is displayed if any chi-square value is above a threshold. An example of a given threshold is provided in FIG. 16. The alert may be provided via a screen on the handheld X-ray imaging device, such as that illustrated in FIG. 3.

[0120] Referring to FIG. 15, a flow diagram depicting a procedure for determining structural integrity of a target object is shown. The procedure illustrated in FIG. 15 includes stages 1310, 1320a, and 1320b previously illustrated and described in relation to FIG. 13.

[0121] The procedure of FIG. 15 further includes stages 1532, 1534, and 1536. At stage 1532, a side of the generated scatter intensity profile 1320b is reflected over a line of symmetry, which is illustrated in later FIGs. 17A, 17B, 18A, and 18B. At a stage 1334, chi square values are calculated for each sub region of the scatter intensity profile between the scatter intensity profile generated consistent with stage 1320b and the reflected profile consistent with stage 1532.

[0122] At stage 1536, similar to that of stage 1336 of FIG. 13, an alert is displayed if any chi-square value is above a threshold. An example of a given threshold is provided in a later figure, FIG. 16. The alert may be provided via a screen on the handheld X-ray imaging device, such as that illustrated in FIG. 3.

[0123] Referring to FIG. 16, a graph is provided to illustrate the fitting of a parabolic curve to the pipe region in the detected scatter profile, and the identification of a subregion that deviates significantly from the fitted curve, corresponding to the embodiment shown in FIG. 13.

[0124] Referring to FIG. 17A, a scatter intensity' profile 562 is shoyvn. Scatter intensity profile 562 is a subregion 1652 of the scatter intensity profile of FIG. 16.Subregion 1652 has two profiles, for example a left side profile 1756 and aright side profile 1758, which are determined by an axis of symmetry-. FIG. 17B shows the reflection of the right side profile 1758’ of the subregion 1652 over the axis of symmetry onto the left side profile 1756. FIG. 17A and 17B correspond to stage 1532 of FIG. 15. In this example, 17A and 17B illustrate a scatter intensity profile consistent with a clean, corrosion-free pipe segment.

[0125] Referring to FIG. 18A, a scatter intensity profile 562 is shown. Similar to the process described in FIGs. 17A and 17B, one side of the scatter intensity profile is reflected about an axis of symmetry onto the other side. In FIG. 18B. an irregularity may be found where there is an identification of a subregion where the first side of the scatter intensity profile 1756 and the reflected scatter intensity profile 1758’ differ, which correspond to stage 1532 of FIG. 15. In this example, FIG. 18A and FIG. 18B illustrate ascatter intensity profile consistent for the case of a corroded pipe. FIG. 18A shows the profile before reflection, and FIG. 18B shows the profile after reflection.

[0126] Referring to FIG. 19, a graph is shown illustrating a subregion of a scatter intensity profile 1982 (upper graph), with a reflected scatter intensity profile layered atop it. The lower graph is a plot of the chi square values of each subregion calculated from the difference between the left profile and the right reflected profile. Each subregion 1982 includes of a set of seven consecutive pixels in the scatter profiles. FIG. 19 also illustrates a threshold 1980. This threshold may assist in determining whether there is a structural irregularity, consistent with stage 1536 of FIG. 15.

[0127] Referring to FIG. 20, a perspective-view diagram of a scanning system using an elliptical pattern in which an incident X-ray scanning beam scans in a circular or other elliptical pattern across a surface of an insulated pipe is provided. The scanning system of FIG. 20 includes similar elements to that of FIG. 4. However, the system is designed to produce an elliptical pattern beam trajectory' 2060. The incident beam forms a circle or ellipse pattern as it scans across the surface of the insulated pipe.

[0128] Referring to FIG. 21 A. a graph is provided illustrating a scatter intensity profile obtained using the elliptical scanning arrangement of FIG. 20, consistent with no surface irregularities present on the pipe in the scanning locations of the target object. In contrast, FIG. 21B is a graph illustrating a similar scatter intensity profile of FIG. 21 A, but showing a valley on the scatter intensity profile that may be consistent with a !4" hemispherical shaped irregularity present on a surface of the pipe. The graphical representations of the scatter intensity plots where the scan line is an ellipse produce a somewhat sinusoidal shaped plot.

[0129] Referring to FIG. 22, a flow diagram is shown illustrating a procedure 2200 for determining structural integrity of a target object consistent with a first specific embodiment. The method 2200 includes a stage 2210, a stage 2220, and a stage 2234. At stage 2210, a beam of penetrating radiation is scanned over the target object in a pattern. At stage 2220, scattered radiation that is scattered from the target object is detected as a function of position of the beam of the penetrating radiation in the pattern. The detection as a function of position results in generation of a scatter intensity profile of the target object over the pattern. At stage 2234, structural integrity of the target object is determined based on the scatter intensity profile.

[0130] Referring to FIG. 23, with further reference to FIGs. 1-22, a flow diagram is shown illustrating a procedure 2340 for determining structural integrity of a target object, which is a first general implementation of the procedure 2200. Procedure 2340 includes stages 2210 and 2220. It also includes a stage 2330, which is one example of the stage 2234, wherein structural integrity of the target object is determined based on the scatter intensity profile. Specifically, stage 2330 is used to determine structural integrity by a sub-stage 2332, a sub-stage 2334, and a sub-stage 2336. At stage 2332, a mathematical function is fit to the scatter intensity profile to determine a best fit mathematical function. At stage 2334, a variance of the scatter intensity' profile from the best fit mathematical function (determined in stage 2332) is calculated. At stage 2336, an indication of structural integrity consistent with the variance is output.

[0131] In one example, the mathematical function used for stage 2332 is a polynomial curve. In an example, the polynomial curve is the parabola described in connection with FIG. 16. However, in other examples, the polynomial cun e can be a section of an ellipse or another function or section of a function, such as a first order, second order, third order, or higher order polynomial chosen to fit an expected scatter intensity profile for a particular target object, such as when the target object is in a clean state, free of irregularities. A best fit mathematical function, as used herein, is a function with parameters chosen so as to minimize variance over the curve in some manner, such as by evaluating chi square over the curve or a region thereof.

[0132] Referring to FIG. 24, with further reference to FIGs. 1-23, a flow diagram is shown illustrating a procedure 2400 for determining structural integrity of a target object, which is a second general implementation of the procedure 2200. Procedure 2400 includes stages 2210 and 2220. It also includes a stage 2430, which is one example of the stage 2234, wherein structural integrity of the target object is determined based on the scatter intensity profile. Specifically, stage 2430 is used to determine structural integrity by a stage 2462 comparing the scatter intensity profile to a set of templates, a stage 2464 determining a template of the set of templates that has a best correspondence to the scatter intensity profile, a stage 2466 calculating a variance of the scatter intensity profile from the template, and a stage 2336 outputting an indication of structural integrity consistent with the variance.

[0133] Referring to FIG. 25, with further reference to FIGs. 1-24, a flow diagram is shown illustrating a procedure 2500 for determining structural integrity of a target object,which is a third general implementation of the procedure 2200. Procedure 2500 includes stages 2210 and 2220. It also includes a stage 2330. which is one example of the stage 2234, wherein structural integrity of the target object is determined based on the scatter intensity profile. Specifically, stage 2330 is used to determine stmctural integrity by a stage 2328 folding a second side of the scatter intensity profile onto a first side of the scatter intensity7profile with respect to an axis of symmetry, a stage 2360 calculating a variance between the first side of the scatter intensity profile and the folded second side of the scatter intensity profile, and a stage 2336 outputting an indication of structural integrity consistent with the variance.

[0134] With further reference to FIGs. 22-25, many optional additional or alternative sub-stages may be performed as part of specific examples of the embodiment and implementations, as described hereinafter.

[0135] Additionally, outputting the indication of the structural integrity may include identifying an irregularity on a surface of the target object consistent with the variance exceeding a threshold, which is illustrated in previous FIG. 19.

[0136] Additionally or alternatively, the variance of the scatter intensity profile is a chi square value, such as calculated as described in connection with FIG. 13.

[0137] Additionally or alternatively, outputting the indication is to a machine display, such as the monitor and screens illustrated in FIGs. 1-3, respectively. The indication may be displayed on the same screen as an X-ray image of the target object, or in another location. In some implementations, the indication is not displayed.

[0138] Additionally or alternatively, the target object may include a pipe. The pipe may be an insulated pipe, such as illustrated in FIG. 4. This insulated pipe may also include cladding thereon, as shown in FIG. 4.

[0139] Additionally or alternatively, the target object may include a tank. The tank may also be an insulated tank, as illustrated in FIG. 28, for example.

[0140] Additionally or alternatively, the penetrating radiation may be from an X-ray imaging device, such as the X-ray imaging systems 100, 200, 300, or 400, or from X-ray imaging devices described hereinafter.

[0141] Additionally or alternatively, the X-ray imaging device may be a backscatter X-ray imaging device.

[0142] Additionally or alternatively, the X-ray imaging device may be a handheld X-ray imaging device.

[0143] Additionally or alternatively, the method of any one of claims 1-15, wherein the pattern includes a scanned line across the target object.

[0144] Additionally or alternatively, the scan pattern includes an ellipse, such as the example shown in FIG. 20.

[0145] Additionally or alternatively, the penetrating radiation includes source X-rays, the method further including generating the source X-rays with an end-point energy greater than about 50keV.

[0146] Additionally or alternatively, the penetrating radiation may be generated using a radioactive isotopic source. The radioactive isotopic source may comprise Co-57, for example, or another radioactive isotopic source.

[0147] Additionally or alternatively, the indication of structural integrity may include an approximate position of an irregularity on the target object. The indication may also include an approximate position of an irregularity below an insulation material on an outer portion of the target object. The indication may also include at least one characteristic of an irregularity' at the target object, for example: an approximate length, an approximate width, an approximate depth, or combination thereof. The indication may also include a type of surface irregularity at the target object, such an air canty, a rust-filled cavity, a corrosion deposit, or combination thereof.

[0148] Additionally or alternatively, the methods illustrated in FIGs. 22-25 may include further elements substantially as shown in any of the drawings or substantially as described herein. This includes elements of existing systems described in reference to FIGs. 1-3, which, when incorporated into embodiments, can provide synergistic advantages.

[0149] Referring to FIG. 26, with further reference to FIGs. 1-25, a schematic diagram is provided illustrating a system 2600 for determining the structural integrity of a target object 2612, using penetrating radiation, according to a second specific embodiment. The system 2600 includes a penetrating radiation scanning module 2616 configured to output a scanning pencil beam of the penetrating radiation 2608 over the target object 2612 in a pattern 2660. The system 2600 further includes a scatter radiation detector 2640 configured to detect scattered radiation 2620 that is scattered from the target object 2612 as a function of position of the scanning beam of the penetrating radiation in the pattern 2660. The detection of scattered radiation 2620 results in the scatter radiation detector 2620 generating a scatter intensity profile 2672 of the targetobject over the pattern. The generated scatter intensity7profile 2672 is provided to the structural integrity determination module 2624, which is configured to output an indication of structural integrity 2674 of the target object based on the scatter intensity profile. The structural integrity determination module 2624 can include a set of processors, for example, or a set of software instructions running on such a set of processors, for example. In one implementation, the set of processors is located apart from the X-ray scanning module, such as outside of a housing of a handheld X-ray scanning system, for example. In such examples, the set of processors and the scatter radiation detector 2620 can be communicatively coupled to each other. The indication of structural integrity' 2674 is based on the scatter intensity' profile 2672.

[0150] An example of the penetrating radiation scanning module 2616 is the X-ray scanning module 116 in FIG. 1. An X-ray scanning module may generally include a source of X-rays, such as the tube the X-ray tube of FIG. 1 , together with a chopper wheel, such as the disk chopper wheel of FIG. 1. In other implementations, the X-ray scanning module may further include a collimator such as that illustrated in FIG. 1.

[0151] An example of the scanning beam of penetrating radiation 2608 is the X-ray pencil beam 108 of FIGs. 1 and 4. An example of penetrating radiation is electromagnetic radiation, such as gamma rays, or such as the source X-rays 106 of FIG. 1. Further, in other implementations, the penetrating radiation includes gamma rays from a radioactive source, or X-rays or gamma rays from an accelerator, such as from a linear accelerator, for example. Furthermore, other types of penetrating radiation are within the scope of embodiments.

[0152] Examples of a target object include insulated pipe, such as the pipe 420 in FIG. 4. as well as insulated tank 2820 of FIG. 28. The target object need not be insulated. The target object, or a scanned area including the target object, may include several objects. The target object need not be stationary’.

[0153] The pattern 2660 may be a line, such as the scan line pattern 160 of FIG. 1, or elliptical pattern, such as the elliptical pattern 2060 in FIG. 20.

[0154] Scattered radiation 2620 may be backscatter radiation that is further received by the scatter radiation detector 2640. One example of a scatter radiation detector 2620 is the scatter radiation detector 440 of FIG. 4.

[0155] The generated scatter intensity’ profile 2672 may be represented graphically, such as in FIG. 27. However, the generated scatter intensity profile 2672 need not berepresented graphically and may be represented in data or plotted differently than show n in FIG. 27.

[0156] The structural integrity determination module 2624 indicates determination of structural integrity which may include a determination of an irregularity such as a whole or rust deposit this indication may be a visual indication, such as an output to a screen such as the screen shown in FIG. 2, may be an audio indication, may be a combination of visual and audio indications, or may be another indication type known to persons with ordinary skill in the art. The indication of structural integrity may be provided in form of an output signal to another instrument or to another module (not shown) that may optionally be provided as part of the system 2600.

[0157] A determination of structural integrity may be an indication that suggests an irregularity on the target object, such as a rust deposit or a hole. A wide variety of methods may be used to determine the structural integrity, including a method wherein a variance value above a threshold indicates a compromised structural integrity, or a method wherein a peak or valley on a scatter intensity profde indicates compromised structural integrity.

[0158] Additionally or alternatively, the system illustrated in FIG. 26 may include further elements substantially as shown in any of the drawings or substantially as described herein. This includes elements of existing systems described in reference to FIGs. 1-3, which, when incorporated into embodiments, can provide synergistic advantages. This further includes system configuration such that any of the processes and actions described in connection with the first specific embodiment may be performed by the system. For example, the structural integrity determination module may include a set of processors configured to execute computer instructions such that the functional fitting, variance analysis, reflection, and / or template matching may be performed thereby. The set of processors may further be configured to generate an image of the target obj ect, such as the image illustrated on the screen of FIG. 2 or the images illustrated in FIGs. 5 A and 5B, for example, and to analyze the image to produce the scatter intensity profile data.

[0159] Referring to FIG. 27, with further reference to FIGs. 1-26, a graphical representation of a scatter intensity profile 2772 is provided. This is one way to represent the scatter intensity profile 2672, how ever, it is not the only way to represent the scatter intensity7profile. Other representations of a scatter intensity profile include data that are not shown graphically. Referring to FIG. 28, a cross-sectional diagram is provided whichillustrates a positioning of a handheld X-ray imaging system 400. This cross-sectional diagram illustrates X-ray imaging system 400, which is shown in FIG.4 but differs from FIG. 4 in the way that the target object is an insulated tank 2820. instead of a pipe 420.

[0160] Another system within the scope of the present disclosure, according to a third specific embodiment, also can determine structural integrity of a target object, likewise using penetrating radiation. The system includes means for scanning a beam of the penetrating radiation over the target object in a pattern. The system further includes means for detecting scattered radiation that is scattered from the target object as a function of position of the beam of the penetrating radiation in the pattern so as to generate a scatter intensity' profile of the target object over the pattern. The system still further includes means for determining structural integrity of the target object based on the scatter intensity profile. The means for scanning the beam, means for detecting scattered radiation, and means for determining structural integrity of the target object will be readily apparent to those skilled in the art in reference to FIGs. 1-29 and the related disclosure.

[0161] Additionally or alternatively, the system according to the third specific embodiment may include further elements substantially as shown in any of the drawings or substantially as described herein. This includes elements of existing systems described in reference to FIGs. 1-3, which, when incorporated into embodiments, can provide synergistic advantages. This further includes system configuration such that any of the processes and actions described in connection with the first specific embodiment may be performed by the system. For example, the structural integrity determination module may include a set of processors configured to execute computer instructions such that the functional fitting, variance analysis, reflection, and / or template matching may be performed thereby. The set of processors may further be configured to generate an image of the target object, such as the image illustrated on the screen of FIG. 2 or the images illustrated in FIGs. 5A and 5B, for example, and to analyze the image to produce the scatter intensity' profile data. Further elements may include optional system configurations consistent with the description of the second specific embodiment hereinabove.

[0162] Implementation Clauses

[0163] Implementation examples are provided in the following numbered clauses. The numbered clauses represent some embodiments of the present invention and potentialclaims. (The actual claims are provided at the end of this application.) These clauses form a part of the written description of this application. Accordingly, subject matter of the following clauses may be presented as claims in later proceedings involving this application or any application claiming priority based on this application. Inclusion of such clauses should not be construed to mean that the claims do not cover the subject matter of the clauses. Thus, a decision not to present these clauses as claims in later proceedings should not be construed as a donation of the subject matter to the public.

[0164] Without limitation, potential subject matter that may be claimed includes:

[0165] Clause 1. A method for determining structural integrity of a target object using penetrating radiation, the method comprising:a. scanning a beam of the penetrating radiation over the target object in a pattern;b. detecting scattered radiation that is scattered from the target object as a function of position of the beam of the penetrating radiation in the pattern so as to generate a scatter intensity profile of the target object over the pattern; andc. determining structural integrity of the target object based on the scatter intensity profile.

[0166] Clause 2. The method of clause 1, wherein determining structural integrity of the target object comprises:a. fitting a mathematical function to the scatter intensity profile to determine a best fit mathematical function;b. calculating a variance of the scatter intensity profile from the best fit mathematical function; andc. outputting an indication of the structural integrity consistent with the variance.

[0167] Clause 3. The method of clause 2, wherein the mathematical function is a polynomial curve.

[0168] Clause 4. The method of clause 1, wherein determining structural integrity of the target object compnses:a. comparing the scatter intensity7profile to a set of templates,b. determining a template of the set of templates that has a best correspondence to the scatter intensity profile;c. calculating a variance of the scatter intensity profile from the template; andd. outputting an indication of the structural integrity consistent with the variance.

[0169] Clause 5. The method of clause 1, wherein determining structural integrity of the target object comprises:a. folding a second side of the scatter intensity profile onto a first side of the scatter intensity profile with respect to an axis of symmetry; b. calculating a variance between the first side of the scatter intensity profile and the folded second side of the scatter intensity7profile; and c. outputting an indication of the structural integrity consistent with the variance.

[0170] Clause 6. The method of any one of clauses 2-5, wherein outputting the indication of the structural integrity includes identifying an irregularity' on a surface of the target object consistent with the variance exceeding a threshold.

[0171] Clause 7. The method of any of clauses 2-6. wherein the variance is a chi square value.

[0172] Clause 8. The method of any of clauses 2-7, wherein outputting the indication is to a machine display.

[0173] Clause 9. The method of any one of clauses 1-8. wherein the target object includes a pipe.

[0174] Clause 10. The method of clause 9, wherein the pipe is an insulated pipe.

[0175] Clause 11. The method of any one of clauses 1-8, wherein the target object includes a tank.

[0176] Clause 12. The method of clause 11. wherein the tank is an insulated tank.

[0177] Clause 13. The method of any one of clauses 1-12, wherein the penetrating radiation is from an X-ray imaging device.

[0178] Clause 14. The method of any one of clauses 1-13, wherein the X-ray imaging device is a backscatter X-ray imaging device.

[0179] Clause 15. The method of clause 14, wherein the X-ray imaging device is a handheld X-ray imaging device.

[0180] Clause 16. The method of any one of clauses 1-15, wherein the pattern includes a scanned line across the target object.

[0181] Clause 17. The method of any one of clauses 1-15, wherein the pattern includes an ellipse.

[0182] Clause 18. The method of any one of clauses 1-17, wherein the penetrating radiation includes source X-rays, the method further including generating the source X-rays with an end-point energy greater than about 50keV.

[0183] Clause 19. The method of any one of clauses 1-18, further comprising generating the penetrating radiation using a radioactive isotopic source.

[0184] Clause 20. The method of clause 19, wherein the radioactive isotopic source comprises Co-57.

[0185] Clause 21. The method of any one of clauses 2-20, wherein the indication includes an approximate position of an irregularity on the target object.

[0186] Clause 22. The method of clause 21. wherein the indication includes the approximate position of irregularity below an insulation material on an outer portion of the target object.

[0187] Clause 23. The method of any one of clauses 2-22, wherein the indication includes a characteristic of an irregularity at the target object, the characteristic selected from the group consisting of an approximate length, an approximate width, an approximate depth, and combinations thereof.

[0188] Clause 24. The method of any one of clauses 2-23, wherein the indication includes a type of surface irregularity at the target object.

[0189] Clause 25. The method of clause 24, wherein the type of surface irregularity is selected from the group consisting of: an air cavity, a rust-filled cavity, a corrosion deposit, and combinations thereof.

[0190] Clause 26. The method of any one of clauses 2-25, substantially as described herein and / or substantially as described with reference to the drawings.

[0191] Clause 27. A system for determining structural integrity of a target object using penetrating radiation, the system comprising:a. a penetrating radiation scanning module configured to output a scanning beam of the penetrating radiation over the target object in a pattern; b. a scatter radiation detector configured to detect scattered radiation that is scattered from the target object as a function of position of the scanning beam of the penetrating radiation in the pattern so as to generate a scatter intensity profile of the target object over the pattern; andc. a structural integrity determination module configured to output an indication of structural integrity of the target object based on the scatter intensity profile.

[0192] Clause 28. The system of clause 27, further comprising any combination of elements of any of clauses 1-26.

[0193] Clause 29. The system of any one of clauses 27-28, substantially as described herein and / or substantially as described with reference to the drawings.

[0194] Clause 30. A system for determining structural integrity of a target object using penetrating radiation, the method comprising:a. means for scanning a beam of the penetrating radiation over the target object in a pattern;b. means for detecting scattered radiation that is scattered from the target object as a function of position of the beam of the penetrating radiation in the pattern so as to generate a scatter intensity profile of the target object over the pattern; and

[0195] means for determining structural integrity of the target object based on the scatter intensity profile.

[0196] Clause 31. The method of clause 30, further comprising any combination of elements of any of clauses 1-26

[0197] Clause 32. The method of any one of clauses 30-31. substantially as described herein and / or substantially as described herein with reference to the drawings.

[0198] Concluding Considerations

[0199] The embodiments of the invention described above are intended to be merely exemplary. In view of the present description and drawings, numerous variations, modifications, and combinations of parameters are possible. All such variations and modifications are intended to be within the scope of the present invention as defined in any appended claims. Those variations, modifications, and combinations of parameters described herein are examples for purposes of explanation only.

Claims

CLAIMSWhat is claimed is:

1. A method for determining structural integrity of a target object using penetrating radiation, the method comprising:scanning a beam of the penetrating radiation over the target object in a pattern;detecting scattered radiation that is scattered from the target object as a function of position of the beam of the penetrating radiation in the pattern so as to generate a scatter intensity profile of the target object over the pattern; and determining structural integrity of the target object based on the scatter intensity profile.

2. The method of claim 1, wherein determining structural integrity of the target object comprises:fitting a mathematical function to the scatter intensity profile to determine a best fit mathematical function;calculating a variance of the scatter intensity profile from the best fit mathematical function; andoutputting an indication of the structural integrity consistent with the variance.

3. The method of claim 2, wherein the mathematical function is a polynomial curve.

4. The method of claim 1, wherein determining structural integrity of the target object comprises:comparing the scatter intensity profile to a set of templates,determining a template of the set of templates that has a best correspondence to the scatter intensity profile;calculating a variance of the scatter intensity profile from the template; and outputting an indication of the structural integrity consistent with the variance.

5. The method of claim 1, wherein determining structural integrity of the target object comprises:folding a second side of the scatter intensity profile onto a first side of the scatter intensity profile with respect to an axis of symmetry;calculating a variance between the first side of the scatter intensity profile and the folded second side of the scatter intensity profile; andoutputting an indication of the structural integrity consistent with the variance.

6. The method of any one of claims 2-5, wherein outputting the indication of the structural integrity includes identifying an irregularity on a surface of the target object consistent with the variance exceeding a threshold.

7. The method of any of claims 2-6, wherein the variance is a chi square value.

8. The method of any of claims 2-7, wherein outputting the indication is to a machine display.

9. The method of any one of claims 1-8, wherein the target object includes a pipe.

10. The method of claim 9, wherein the pipe is an insulated pipe.

11. The method of any one of claims 1-8, wherein the target object includes a tank.

12. The method of claim 11, wherein the tank is an insulated tank.

13. The method of any one of claims 1-12, wherein the penetrating radiation is from an X-ray imaging device.

14. The method of any one of claims 1-13, wherein the X-ray imaging device is a backscatter X-ray imaging device.

15. The method of claim 14, wherein the X-ray imaging device is a handheld X-ray imaging device.

16. The method of any one of claims 1-15, wherein the pattern includes a scanned line across the target object.

17. The method of any one of claims 1-15, wherein the pattern includes an ellipse.

18. The method of any one of claims 1-17, wherein the penetrating radiation includes source X-rays, the method further including generating the source X-rays with an end-point energy greater than about 50keV.

19. The method of any one of claims 1-18, further comprising generating the penetrating radiation using a radioactive isotopic source.

20. The method of claim 19, wherein the radioactive isotopic source comprises Co-57.

21. The method of any one of claims 2-20, wherein the indication includes an approximate position of an irregularity on the target object.

22. The method of claim 21, wherein the indication includes the approximate position of irregularity below an insulation material on an outer portion of the target object.

23. The method of any one of claims 2-22, wherein the indication includes a characteristic of an irregularity at the target object, the characteristic selected from the group consisting of: an approximate length, an approximate width, an approximate depth, and combinations thereof.

24. The method of any one of claims 2-23, wherein the indication includes a type of surface irregularity at the target object.

25. The method of claim 24, wherein the type of surface irregularity is selected from the group consisting of: an air cavity, a rust-filled cavity, a corrosion deposit, and combinations thereof.

26. The method of any one of claims 2-25, substantially as described herein and / or substantially as described with reference to the drawings.

27. A system for determining structural integrity of a target object using penetrating radiation, the system comprising:a penetrating radiation scanning module configured to output a scanning beam of the penetrating radiation over the target object in a pattern;a scatter radiation detector configured to detect scattered radiation that is scattered from the target object as a function of position of the scanning beam of the penetrating radiation in the pattern so as to generate a scatter intensity profile of the target object over the pattern; anda structural integrity determination module configured to output an indication of structural integrity of the target object based on the scatter intensity profile.

28. The system of claim 27, further comprising any combination of elements of any of claims 1-26.

29. The system of any one of claims 27-28, substantially as described herein and / or substantially as described with reference to the drawings.

30. A system for determining structural integrity of a target object using penetrating radiation, the method comprising:means for scanning a beam of the penetrating radiation over the target object in a pattern;means for detecting scattered radiation that is scattered from the target object as a function of position of the beam of the penetrating radiation in the pattern so as to generate a scatter intensity profile of the target object over the pattern; and means for determining structural integrity of the target object based on the scatter intensity profile.

31. The method of claim 30, further comprising any combination of elements of any of claims 1-2632. The method of any one of claims 30-31, substantially as described herein and / or substantially as described herein with reference to the drawings.

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