Detector with focus alignment pixels

Abstract

The system includes an energy source and a detector. The energy source is configured to emit energy from the focus. The detector includes an array of pixels. Each pixel in the array of pixels has a centerline extending longitudinally through the pixel. The centerline of each pixel is in focus alignment with the focal point of the energy source. Each pixel receives a selected amount of energy from an energy source through the object.

Description

Technical Field

[0001] The technical field relates to energy detection, and more particularly to energy detectors for detecting signs or anomalies in objects. Background Art

[0002] Computed tomography (CT) scanning technology uses x-rays, which are directed at an object by an x-ray source. The x-rays pass through the object and are received by a detector. CT scanning has been used in the medical field, but can also be used for other applications, such as scanning aircraft engine parts. In terms of aircraft engine parts, CT scanning can be used to detect signs and anomalies in these parts. Once these signs and anomalies are detected, further decisions can be made regarding the disposition of the part. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Various needs can be met, at least in part, by providing a method for scanning an object using a focally aligned pixel array, particularly when studied in conjunction with the accompanying drawings. A complete and enabling disclosure of the various aspects of the present description, including the best mode thereof, is set forth in the specification, which refers to the accompanying drawings, wherein:

[0004] Figure 1 A block diagram including a scanning system according to various embodiments of these teachings;

[0005] Figure 2 A block diagram including a scanning system according to various embodiments of these teachings;

[0006] Figure 3 including a flow chart of operating a scanning system according to various embodiments of these teachings;

[0007] Figure 4 includes diagrams of rectangular pixel arrays according to various embodiments of these teachings;

[0008] Figure 5A A diagram including trapezoidal pixels according to various embodiments of these teachings; and

[0009] Figure 5B Included are diagrams of trapezoidal pixel arrays used in detectors according to various embodiments of these teachings.

[0010] The elements shown in the figures are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the size and / or relative positioning of certain elements in the figures may be exaggerated relative to other elements to help improve the understanding of the various embodiments of the present teachings. In addition, common but easy to understand elements that are useful or necessary in commercially feasible embodiments are generally not depicted to facilitate a clearer view of these various embodiments of the present teachings. Certain actions and / or steps may be described or depicted in a specific order of occurrence, and those skilled in the art will understand that such specificity about the order is not actually required. DETAILED DESCRIPTION

[0011] In the approach provided herein, an x-ray sensor array or detector (e.g., a grouping of scintillator pixels) is constructed so that the centerline of each pixel is aligned with the focal focus of the x-ray source. In one example, the rectangular pixels of the detector are arranged along an arc. In another example, each pixel is cut into a trapezoid (as seen in a longitudinal cross-section) so that the outer edge of the pixel is radially aligned with the x-ray beam. Either construction enables the use of thinner pixels in the detector, which in turn enables the construction of detection modules with smaller geometric pitches. These structures improve alignment capabilities, thereby reducing image artifact issues, and achieve higher spatial resolution due to reduced pixel pitch.

[0012] Beneficially, the methods provided herein ensure optimal alignment of x-ray beam pixels (e.g., sensor scintillator pixels) in the detector. A collimator can be used in these methods, wherein the collimator is placed between the energy source and the object and / or between the object and the detector. When a collimator is used, this method ensures that the collimator is correctly aligned with the sensor scintillator pixels. The images produced by these methods avoid image problems caused by misalignment, such as containing image artifacts, including stripes, bands, rings, etc. This method is particularly useful in high-energy CT scanners, where the pixel depth of the x-ray sensor becomes very deep (approximately 20-50 mm). This is compared to medical CT scanners (wherein the pixel depth is approximately 2-3 mm).

[0013] The terms and expressions used herein have the ordinary technical meanings given to these terms and expressions by those skilled in the art as described above, unless otherwise specifically defined herein. Unless otherwise expressly stated, the word "or" used herein should be interpreted as having a disjunctive structure rather than a conjunctive structure. Unless otherwise specified herein, the terms "connect", "fix", "attach to", etc. refer to both direct connection, fixation or attachment and indirect connection, fixation or attachment through one or more intermediate components or features.

[0014] The singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise.

[0015] Throughout the specification and claims, approximating language is used to modify any quantitative representation that can be permissibly varied without resulting in a change in the basic function to which it is related. Thus, values ​​modified by terms such as "about," "approximately," and "substantially" are not limited to the precise values ​​specified. In at least some cases, approximate language may correspond to the precision of an instrument used to measure the value, or the precision of a method or machine used to construct or manufacture a component and / or system. For example, approximate language may mean within a 10% margin.

[0016] The foregoing and other benefits may become clearer through a thorough review and study of the following detailed description.

[0017] Reference now Figure 1 , system 100 includes an energy source 102 (which may also be referred to as a transmitter) that transmits energy from a focal point 104. An object 106 is disposed in a path of the energy transmitted from the focal point 104. Thus, the object 106 receives energy from the energy source 102. At least some of the energy passes through the object 106.

[0018] The system 100 includes a detector 108. The detector 108 receives energy from the energy source 102 that passes through the object 106. In various aspects, the detector 108 includes an array of pixels 110, 112, 114, 116, and 118. Each pixel 110, 112, 114, 116, and 118 in the array has a centerline 111, 113, 115, 117, and 119 that extends longitudinally through each pixel (as used herein, the longitudinal direction is the direction of travel or movement of x-rays from the energy source 102). Each centerline 111, 113, 115, 117, and 119 of each pixel 110, 112, 114, 116, and 118 is in focus alignment with the focal point 104 of the energy source. "In focus alignment" means that the centerline extends to the focal point 104. Each pixel receives a selected amount of energy from the energy source 102 that passes through the object 106.

[0019] In one example, energy source 102 is an x-ray source that emits radiation at an x-ray wavelength. For example, a cathode (e.g., a filament) of energy source 102 is heated to produce electrons. A potential voltage (e.g., measured in the kilovolt range) in an x-ray tube directs these electrons into a target (anode), thereby producing x-rays. Focus 104 is defined as the region of the apparent source of x-rays. In this case, focus 104 is the region of the anode surface that receives the electron beam from the cathode and is the apparent source of x-rays (as viewed from detector 108).

[0020] The area of ​​the focal spot 104 can vary. Generally speaking, the larger the area of ​​the focal spot, the less detail in the resulting x-ray image. In some aspects, this result is attributed to a larger area of ​​penumbra or edge blur associated with the image. As described herein, the energy source 102 is an x-ray energy source, but it is understood that other examples of energy sources operating in different frequency ranges or wavelengths are possible.

[0021] Object 106 may be any object configured to be imaged. In one example, object 106 may be an aircraft engine component (e.g., a turbine blade, a stator, a rotor hub, etc.). In other examples, object 106 may be a part of another industrial machine. In other examples, object 106 may be a human or a part of a human.

[0022] Detector 108 (also referred to herein as an array of pixels) includes pixels 110, 112, 114, 116, and 118, which form an array. Detector 108 may also include electronic or electrical devices for changing or processing the energy received by pixels 110, 112, 114, 116, and 118.

[0023] The detector 108 may also be referred to as a focused pixel array because each of its pixels 110, 112, 114, 116, and 118 is aligned with the focal point 104 of the energy source 102. It will be appreciated that for simplicity, Figure 1 The example shown shows only five pixels in one direction, and there can be any number of pixels. For example, the detector can be an array of rectangular two-dimensional pixels (e.g., 1,000 pixels x 1,000 pixels). In other examples, the array of pixels can include other numbers of pixels (e.g., 2, 3, 4, etc.) and / or be arranged in other one-dimensional or two-dimensional configurations.

[0024] Each pixel 110, 112, 114, 116, and 118 can be made of a scintillator such as Lumex. In one example, each pixel 110, 112, 114, 116, and 118 has a size of 80 mm x 10 mm x 10 mm. In other examples, the pixels can have different sizes and / or be made of other materials.

[0025] A photodiode or other conversion circuit may be attached to the back of each pixel 110, 112, 114, 116, 118 or may be combined with each pixel 110, 112, 114, 116, 118. The absorbed x-rays generate light in the scintillator, which is then converted into an electric current. The intensity of the current generated is proportional to the energy received.

[0026] As described above, the center lines 111, 113, 115, 117, and 119 extend through each pixel 110, 112, 114, 116, 118 in the longitudinal direction and pass through the center of the corresponding pixel 110, 112, 114, 116, 118. The center lines 111, 113, 115, 117, and 119 are in focus alignment with the focal point 104. In focus alignment means that the center lines 111, 113, 115, 117, and 119 are aligned with or intersect with some portion of the focal point 104. In some cases, all of the center lines 111, 113, 115, 117, and 119 intersect with the same point in the focal point 104, while in other examples, the center lines 111, 113, 115, 117, and 119 are aligned with different points within the same focal point 104. It will be appreciated that the focal point 104 is in fact an area, not a single mathematical point. Pixels 110, 112, 114, 116, and 118 are constructed and / or arranged along arc 142. Thus, in some aspects, each pixel 110, 112, 114, 116, and 118 is the same distance from the focal point 104. In some aspects, the radius of the arc 142 is based on the distance from the focal point 104. Centerlines 111, 113, 115, 117, and 119 intersect the arc 142. In some aspects, the energy source 102 and the detector 108 are coupled together by a structure such as a mounting structure, a housing, and / or a bracket to maintain a fixed distance between these elements. In other examples, the energy source 102 and the detector 108 can be completely different components positioned on a platform such as a workbench.

[0027] As a result of the alignment, each pixel 110, 112, 114, 116, 118 provides improved alignment compared to a previous approach without alignment. In other words, pixels farther from the center (110, 118) are in the same focus alignment as the center pixel (114). Since all pixels 110, 112, 114, 116, and 118 are aligned, significantly improved image quality is provided.

[0028] The provided focus alignment rectangular pixel array can support deeper pixel lengths (in the x-ray direction). If the focus alignment pixel has a trapezoidal cross-section, the pixel length can theoretically be infinite, allowing the length to be as long as desired. A deeper focus is an advantage because it can increase detection sensitivity.

[0029] The system 100 includes a first controller 124 that can be communicatively coupled to the detector 108. The first controller 124 receives information from the detector 108, including electrical signals generated by the pixels 110, 112, 114, 116, and 118, and can be coupled to a user electronic device having a display screen (e.g., a personal computer, a laptop, or a smart phone, to name a few examples). The first controller 124 can be any microcontroller, computer, or processor-based device having a processor, memory, and programmable input / output peripherals, typically designed to control the operation of other components and devices. It is further understood that it includes common accessory accessory devices, including memory, transceivers for communicating with other components and devices, etc.

[0030] The first controller 124 may be configured (e.g., by using a corresponding program stored in memory) to perform one or more steps, actions, and / or functions described herein, such as processing and displaying information received from the detector 108. The first controller 124 may include a memory including computer instructions that implement any of the functions described herein.

[0031] The system 100 also includes a second controller 126 that can be communicatively coupled to the energy source 102. In one example, the second controller 126 can activate / deactivate the energy source, adjust the power of the energy source 102, adjust the timing of the x-rays emitted from the energy source 102, and / or otherwise control the operation of the energy source 102. The second controller 126 can also receive instructions from a human operator (e.g., via an electronic interface, such as a personal computer, laptop, or smartphone, to name a few examples) to control the operation of the energy source 102. The structure of the second controller 126 can be the same or similar to the structure of the first controller 124. Both controllers 124 and 126 can also be part of the same controller or computer system.

[0032] Reference now Figure 2 Another example of a system 100 includes an energy source 102 that emits energy from a focal point 104 . Figure 2 The system 100 shown in FIG. 1 is similar in its components to that of FIG. 1 except that a collimator 130 is disposed between the object 106 and the detector 108. Figure 1 All in Figure 2 The other components in the same Figure 1 Elements with the same number in FIG. 1 are similar or identical. Their description will not be repeated here. In some cases, such as when out-of-focus alignment causes artifacts and reduced sensitivity in the resulting data, it is beneficial to use a collimator 130.

[0033] Although Figure 2The collimator 130 in the embodiment is disposed between the object 106 and the detector 108, but it is understood that the collimator 130 can be disposed at other locations, such as between the energy source 102 and the object 106. In addition, a system with multiple collimators can also be provided. In an example system, one collimator is disposed between the energy source 102 and the object 106, and another collimator is disposed between the object 106 and the detector 108.

[0034] The collimator 130 is configured to direct the x-ray beam received from the energy source 102 in a direction parallel to the slots 132, 134, 136, 138, and 140 in the collimator 130. In this regard, x-rays that do not travel in a parallel direction (with respect to the slots 132, 134, 136, 138, and 140) may be absorbed by the sides of the slots 132, 134, 136, 138, and 140. In various aspects, the collimator 130 is built on an arc 142 and is also focused aligned with the focal point 104. It can be seen that the pixels 110, 112, 114, 116, and 118 are aligned with a corresponding one of the slots 132, 134, 136, 138, and 140, respectively. It can further be seen that center lines 111 , 113 , 115 , 117 , and 119 pass through the centers of slots 132 , 134 , 136 , 138 , and 140 , and that the center lines are in focus alignment with focal point 104 .

[0035] Reference now Figure 3 , describes an example of how an operating system can acquire an image.

[0036] At step 302, energy is emitted from the focal point 104 of the energy source 102. At least some of the energy passes through the object 106. In one example, as previously described, the energy source 102 is an x-ray source, but other examples are possible. In various aspects, the second controller 126 controls or activates the energy source 102 to emit energy.

[0037] In step 304, at least some of the energy that has passed through the object 106 is received by the detector 108 (an array of pixels 110, 112, 114, 116, and 118). As previously described, each pixel 110, 112, 114, 116, and 118 of the detector 108 has a centerline 111, 113, 115, 117, and 119 that extends longitudinally through the pixel 110, 112, 114, 116, and 118. Each centerline 111, 113, 115, 117, and 119 of each pixel 110, 112, 114, 116, and 118 is in focal alignment with the focal point 104 of the energy source 102.

[0038] The energy received at the detector 108 may be conditioned by built-in electronic components (e.g., amplifiers, filters, etc.) or components (e.g., resistors, diodes, transistors, and capacitors) that are integrated or built into each pixel 110, 112, 114, 116, and 118. In addition, the first controller 124 may obtain an electrical signal representing the received energy to further process the electrical signal, such as filtering, noise removal, etc. The controller 124 may then format and display the received energy as an image to a user (e.g., on a user electronic device such as a personal computer, laptop, or smartphone, to name a few examples).

[0039] Once the image has been inspected, further action may be taken at step 306. For example, if object 106 is an aircraft engine component, an indication or anomaly (e.g., a crack) may be determined by manually or automatically inspecting the image. The component may be discarded or repaired. For example, if a crack is detected, the crack in the component may be repaired by any suitable method or means, such as welding or sealing the crack. The component may then be re-inspected to ensure that the crack has been repaired.

[0040] Reference now Figure 4 , an example of an array of pixels 110, 112, 114, 116, and 118, where pixels 110, 112, 114, 116, and 118 are rectangular in longitudinal cross-section (along the direction of travel of x-rays). Center lines 111, 113, 115, 117, and 119 pass through each pixel. Center lines 111, 113, 115, 117, and 119 are aligned with focal point 104 (e.g., Figure 1 shown). Figure 4 The example of FIG. 1 shows the detector (array) 108 with a collimator 130, but it is understood that the collimator 130 may not be used. Figure 4 1 (not shown) passes through the collimator 130 and enters the detector 108. In this example, the rectangular pixels of the detector 108 are arranged along an arc 142 (the same may also be true for the collimator 130). The radius of the arc 142 is the distance to the focal point 104 in various aspects.

[0041] It can be seen that center lines 111, 113, 115, 117, and 119 are not arranged parallel to each other. Instead, pixels 110, 112, 114, 116, and 118 are adjusted or tilted so that center lines 111, 113 are at different angles relative to center line 115. Similarly, center lines 117, 119 are at different angles relative to center line 115. The amount of angular adjustment or tilting can be determined by experimentation and / or mathematical calculation or analysis to ensure that center lines 111, 113, 115, 117, and 119 are in focus alignment with the focal point 104 of the energy source 102.

[0042] Insulator (or shielding material) 123 is disposed between pixels 110, 112, 114, 116, and 118. Housing 125 (formed by insulator 123) may be formed with a groove in the housing, and pixels 110, 112, 114, 116, and 118 are disposed in the groove. Insulator 123 may further absorb stray x-rays and improve image quality. In one example, insulator 123 may be formed of tungsten or steel. Other example materials are also possible. In general, detector 108 does not present a uniform plane to energy source 102 because each pixel surface (facing energy source 102) is rectangular and tilted at an angle different from other pixels in pixels 110, 112, 114, 116, and 118.

[0043] Reference now Figure 5A and Figure 5B , which is an example of an array of pixels 110, 112, 114, 116, and 118, where pixels 110, 112, 114, 116, and 118 are trapezoidal in longitudinal cross-section (along the direction of travel of x-rays). "Trapezoidal" refers to a quadrilateral with only one pair of parallel sides. In this example, each pixel 110, 112, 114, 116, and 118 is cut into a trapezoidal shape (as viewed in longitudinal cross-section) so that the outer edge of the pixel is radially aligned with the x-ray beam.

[0044] Center lines 111, 113, 115, 117, and 119 pass through each pixel. Center lines 111, 113, 115, 117, and 119 are aligned with focal point 104 (e.g., Figure 1 shown).

[0045] As can be seen, center lines 111, 113, 115, 117, and 119 are not arranged parallel to each other. Instead, the cross-sectional shape of pixels 110, 112, 114, 116, and 118 is trapezoidal, so center lines 111, 113 are at different angles relative to center line 115. Similarly, center lines 117, 119 are at different angles relative to center line 115. The exact shape of the trapezoidal cross section is determined experimentally and / or by calculation to ensure that center lines 111, 113, 115, 117, and 119 are in focus alignment with the focal point of energy source 102. In general, due to the trapezoidal shape of pixels 110, 112, 114, 116, and 118, the detector presents a flat surface to energy source 102.

[0046] exist Figure 5A and Figure 5B In the example of FIG. 1 , the shape (in cross section) of pixels 110 , 112 , 114 , 116 , and 118 is a trapezoid. Figure 5A and Figure 5BAs shown, the top and bottom surfaces 151, 153 of each pixel 110, 112, 114, 116, and 118 are not parallel. The front and rear surfaces 155 and 157 of the pixels 110, 112, 114, 116, and 118 are parallel to each other. Generally speaking, the top and bottom surfaces 151, 153 are aligned with the direction of the x-rays. This results in the cross-section of the pixels 110, 112, 114, 116, and 118 being trapezoidal.

[0047] The insulator 123 is positioned between the pixels 110, 112, 114, 116, and 118. The housing 125 may have a groove formed therein, and the pixels 110, 112, 114, 116, and 118 are disposed in the groove. Figure 4 As in the example of , insulator 123 can further absorb stray x-rays and improve image quality.

[0048] Beneficially, the present approaches provide locally aligned pixels in an x-ray sensor module. These approaches provide increased misalignment sensitivity and reduced image artifacts. The present approaches also enable smaller pixel widths and pitches, thereby improving spatial resolution. In addition, these approaches enable increased pixel length (in the x-ray direction), thereby enabling higher energy modules (greater x-ray stopping power due to increased pixel depth or length).

[0049] Further aspects of the invention are provided by the subject matter of the following clauses:

[0050] A system comprising: an energy source that emits energy from a focal point toward an object; and a detector comprising an array of pixels, each pixel in the array of pixels having a center line extending longitudinally through the pixel, the center line of each pixel being focused and aligned with the focal point of the energy source, and each pixel receiving energy from the energy source that passes through the object.

[0051] A system according to any preceding clause, further comprising a collimator arranged between the energy source and the detector.

[0052] A system as in any preceding clause, wherein the collimator comprises a plurality of openings, and wherein each pixel is aligned with one of the plurality of openings of the collimator.

[0053] A system as claimed in any preceding clause, wherein the plurality of openings of the collimator are arranged along an arc.

[0054] A system as described in any preceding clause, wherein the energy source comprises an x-ray energy source.

[0055] A system as described in any preceding clause, wherein each pixel converts received energy into an electrical signal, which is then converted into an image.

[0056] A system according to any of the preceding clauses, wherein each pixel has a rectangular cross-section and is arranged along an arc.

[0057] A system according to any preceding clause, wherein each pixel has a trapezoidal cross-section.

[0058] A system as claimed in any preceding clause, wherein each pixel is separated in the array by shielding material.

[0059] A pixel array comprises: a first pixel, the first pixel being configured to receive energy from an energy source passing through an object, the first pixel having a first centerline extending longitudinally therethrough, wherein the first centerline is focused and aligned with a focal point of the energy source; and a second pixel, the second pixel being configured to receive energy from the energy source passing through the object, the second pixel having a second centerline extending longitudinally therethrough, wherein the second centerline is focused and aligned with the energy source.

[0060] A pixel array according to any of the preceding clauses, wherein the first center line is arranged in a non-parallel relationship with the second center line.

[0061] The pixel array according to any of the preceding clauses further comprises a shielding material arranged between the first pixel and the second pixel.

[0062] The pixel array according to any of the preceding items, wherein the cross-sections of the first pixel and the second pixel are rectangular.

[0063] The pixel array according to any of the preceding items, wherein the cross-sections of the first pixel and the second pixel are trapezoidal.

[0064] A pixel array according to any preceding clause, wherein the energy source comprises an x-ray energy source.

[0065] A pixel array according to any of the preceding items, wherein the first pixel and the second pixel convert received energy into electrical signals.

[0066] A method comprising: emitting energy from a focal point of an energy source, at least some of the energy passing through an object; and receiving at least some of the energy passing through the object at an array of pixels, each pixel in the array of pixels having a centerline extending longitudinally through the pixel, the centerline of each pixel being focused and aligned with the focal point of the energy source.

[0067] The method of any preceding clause, further comprising: wherein receiving at least some of the energy that passed through the object comprises receiving the energy at a collimator, the collimator comprising a plurality of openings.

[0068] A method as in any preceding clause, wherein each pixel is aligned with one of the plurality of openings of the collimator.

[0069] A method as in any preceding clause, wherein the energy source comprises an x-ray energy source.

[0070] A method according to any of the preceding clauses, wherein the cross section of each pixel is rectangular and arranged along an arc.

[0071] A method according to any of the preceding clauses, wherein the cross-section of each pixel is trapezoidal.

[0072] Those skilled in the art will appreciate that various modifications, changes and combinations may be made to the above-described embodiments without departing from the scope of the present invention, and such modifications, changes and combinations should be considered to be within the scope of the inventive concept.

Claims

1. A system, characterized in that: The system comprises: an energy source that emits energy from a focal point toward the object; and A detector comprising an array of pixels, each pixel in the array of pixels having a center line extending longitudinally through the pixel, the center line of each pixel being focused and aligned with the focal point of the energy source, and each pixel receiving energy from the energy source that passes through the object.

2. The system according to claim 1, characterized in that Further included is a collimator disposed between the energy source and the detector.

3. The system according to claim 2, characterized in that Wherein the collimator comprises a plurality of openings, and wherein each pixel is aligned with one of the plurality of openings of the collimator.

4. The system according to claim 3, characterized in that The plurality of openings of the collimator are arranged along an arc.

5. The system according to claim 1, characterized in that Wherein the energy source comprises an x-ray energy source.

6. The system according to claim 1, characterized in that Each pixel converts the received energy into an electrical signal, which is then converted into an image.

7. The system according to claim 1, characterized in that The cross section of each pixel is rectangular and arranged along an arc.

8. The system according to claim 1, characterized in that The cross section of each pixel is trapezoidal.

9. The system according to claim 1, characterized in that Each pixel in the array is separated by a shielding material.

10. A pixel array, characterized in that: The pixel array comprises: a first pixel configured to receive energy from an energy source that passes through an object, the first pixel having a first centerline extending longitudinally therethrough, wherein the first centerline is in focal alignment with a focal point of the energy source; and A second pixel is configured to receive the energy from the energy source that passes through the object, the second pixel having a second centerline extending longitudinally therethrough, wherein the second centerline is in focal alignment with the energy source.

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