Multi-source cone-beam computed tomography

Abstract

Disclosed herein is an apparatus comprising: a first radiation source (12) configured to generate a first divergent radiation beam (11) toward an object (50); a second radiation source (14) configured to generate a second divergent radiation beam (13) toward the object (50); and an image sensor (9000); wherein the object (50) is configured to rotate relative to the image sensor (9000), the first radiation source (12), and the second radiation source (14), and wherein the relative positions among the image sensor (9000), the first radiation source (12), and the second radiation source (14) are fixed.

Description

Technical field

[0002] The disclosure herein relates to cone beam computed tomography (CBCT). [Background Technology]

[0004] Cone-beam computed tomography (CBCT) is a type of computed tomography (CT). Compared to conventional CT, CBCT uses a diverging beam of radiation to illuminate the object being imaged and can provide better image accuracy, shorter scan times, and lower doses. CBCT can be useful in a variety of applications, such as implantology, orthodontics, orthopedics, and interventional radiology. [Summary of the invention]

[0006] Disclosed herein is an apparatus comprising: a first radiation source configured to generate a first divergent radiation beam toward an object; a second radiation source configured to generate a second divergent radiation beam toward the object; and an image sensor; wherein the object is configured to rotate relative to the image sensor, the first radiation source, and the second radiation source, and wherein the relative positions among the image sensor, the first radiation source, and the second radiation source are fixed.

[0007] In certain aspects, the image sensor, the first radiation source, and the second radiation source are stationary.

[0008] In certain aspects, the first divergent radiation beam and the second divergent radiation beam are X-rays having a photon energy less than 5 KeV.

[0009] In certain aspects, the rotation of the object is performed about a rotation axis perpendicular to a device plane that intersects the image sensor, the first radiation source, and the second radiation source.

[0010] In a certain aspect, the apparatus further comprises a platform, wherein the object is physically fixed to the platform, and wherein the platform is configured to rotate relative to the image sensor, the first radiation source, and the second radiation source.

[0011] In a certain aspect, the apparatus further comprises a controller configured to activate and deactivate the first radiation source independently of the second radiation source, and configured to activate and deactivate the second radiation source independently of the first radiation source.

[0012] In some aspects, the apparatus further comprises a shutter configured to controllably block the first diverging radiation beam from reaching the object, and controllably block the second diverging radiation beam from reaching the object.

[0013] In a certain aspect, the image sensor is configured to capture a partial image of the object using the first divergent radiation beam or the second divergent radiation beam.

[0014] In a certain aspect, the image sensor includes a collimator having multiple radiation-transmitting areas and a radiation-blocking area; wherein the radiation-blocking areas are configured to block radiation that will be incident on a blind area of ​​the image sensor, and the radiation-transmitting areas are configured to transmit at least a portion of the radiation that will be incident on an active area of ​​the image sensor.

[0015] In a certain aspect, the device further includes a mask having multiple radiation-transmitting areas and a radiation-blocking area; wherein the radiation-blocking area is configured to block a portion of the first divergent radiation beam that would otherwise pass through the object and impinge on a blind area of ​​the image sensor, and the radiation-transmitting area is configured to transmit at least a portion of the first divergent radiation beam that would otherwise impinge on an active area of ​​the image sensor.

[0016] In a certain aspect, the image sensor includes: a plurality of radiation detectors spaced apart from each other; wherein the image sensor is configured to capture a first partial image of the object by using the radiation detectors and using the first divergent radiation beam, and is configured to capture a second partial image of the object by using the radiation detectors and using the second divergent radiation beam; wherein the image sensor is configured to form an image of the object by stitching the first partial image and the second partial image.

[0017] In a certain aspect, the radiation detectors each include radiation receiving surfaces that are not all parallel to each other.

[0018] In a certain aspect, for each of the radiation detectors, any straight line passing through the radiation detector and the first radiation source or the second radiation source is substantially perpendicular to a radiation receiving surface of the radiation detector.

[0019] In one aspect, when the image sensor captures a first partial image of the object, the first radiation source is located at a first radiation position relative to the object, and when the image sensor captures a second partial image of the object, the second radiation source is located at a second radiation position relative to the object, wherein the first radiation position and the second radiation position are the same.

[0020] In a certain aspect, at least some of the plurality of radiation detectors are arranged in staggered rows.

[0021] In one aspect, the radiation detectors in the same row are uniform in size; wherein the distance between two adjacent radiation detectors in the same row is greater than a width of a radiation detector in the row and less than twice the width in the extension direction of the row.

[0022] In some aspects, at least some of the plurality of radiation detectors are rectangular.

[0023] In some aspects, at least some of the plurality of radiation detectors are hexagonal.

[0024] In a certain aspect, at least one radiation detector among the multiple radiation detectors includes a radiation absorption layer and an electronic device layer; wherein the radiation absorption layer includes an electrode; wherein the electronic device layer includes an electronic system; wherein the electronic system includes: a first voltage comparator, configured to compare the voltage of the electrode with a first threshold, a second voltage comparator, configured to compare the voltage with a second threshold, a counter, configured to record a number of radiation particles reaching the radiation absorption layer, and a controller; wherein the controller is configured to start a time delay from when the first voltage comparator determines that the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold; wherein the controller is configured to start the second voltage comparator during the time delay; wherein the controller is configured to increase the number recorded by the counter by one if the second voltage comparator determines that the absolute value of the voltage is equal to or exceeds the absolute value of the second threshold.

[0025] In a certain aspect, the electronic system further includes an integrator electrically connected to the electrode, wherein the integrator is configured to collect carriers from the electrode.

[0026] In a certain aspect, the controller is configured to activate the second voltage comparator upon the start or expiration of the time delay.

[0027] In a certain aspect, the electronic system further comprises a voltmeter, wherein the controller is configured to cause the voltmeter to measure the voltage when the time delay expires.

[0028] In a certain aspect, the controller is configured to determine the energy of the radiated particles based on the voltage value measured after expiration of the time delay.

[0029] In a certain aspect, the controller is configured to connect the electrode to electrical ground.

[0030] In some aspects, the rate of change of the voltage is substantially zero upon expiration of the time delay.

[0031] In some aspect, the rate of change of the voltage is substantially non-zero upon expiration of the time delay.

[0032] A method is disclosed herein, comprising: for i = 1, ..., M, and j = 1, ..., N, positioning a radiation source (j) and the same object so that the radiation source (j) is at the same relative radiation position (i) relative to the object; when the radiation source (j) is at the relative radiation position (i) relative to the object, directing a divergent radiation beam B from the radiation source (j) to the same radiation source. ij directed toward the object; in the divergent radiation beam B ij When being directed toward the object, a partial image P of a portion of the object is captured using the same image sensor. ij ; and for i = 1, ..., M, by splicing the partial image P ij , j = 1, ..., N, to form a stitched image (i) of the object, wherein the positioning comprises rotating the object relative to the image sensor and the radiation source (j), j = 1, ..., N, wherein the relative positions between the image sensor and the radiation source (j), j = 1, ..., N, are fixed, and wherein M and N are integers greater than 1.

[0033] In some aspects, the image sensor and the radiation source (j), j = 1, ..., N, are stationary.

[0034] In one aspect, the divergent radiation beam B ij It is an X-ray with a photon energy less than 5KeV.

[0035] In a certain aspect, the rotation of the object is performed about a rotation axis perpendicular to a device plane intersecting the image sensor and the radiation source (j) j=1, . . . , N,.

[0036] In some aspects, the object is physically fixed to a platform, and wherein rotating the object comprises rotating the platform.

[0037] In one aspect, each of the radiation sources (j) j = 1, ..., N, is deactivated when the radiation source is not at a certain relative radiation position relative to the radiation position (i) i = 1, ..., M.

[0038] In some aspects, when the radiation source is not at a relative radiation position of the relative radiation position (i) i=1,...,M, the radiation generated by each of the radiation sources (j), j=1,...,N, is blocked.

[0039] In one aspect, the divergent radiation beam B that passes through the object and is incident on the blind area of ​​the image sensor ij , i = 1,…,M, and j = 1,…,N, a portion of each diverging radiation beam is blocked.

[0040] In one aspect, the image sensor includes a plurality of radiation detectors spaced apart from each other, and the partial image P of a portion of the object is captured. ij The method comprises: receiving the divergent radiation beam B having passed through the object by using the radiation detector; ij part of.

[0041] In a certain aspect, the radiation detectors each include radiation receiving surfaces that are not all parallel to each other.

[0042] In a certain aspect, for each of the radiation detectors, any straight line passing through the radiation detector and any of the radiation sources (j) j=1, . . . , N, is substantially perpendicular to a radiation receiving surface of the radiation detector.

[0043] In one aspect, for i = 1, ..., M, the portion of the image P ij , j = 1,…,N, with spatial overlap.

[0044] In one aspect, the method further comprises forming a 3D (three-dimensional) image of the object surface of the object based on the stitched images (i), i=1, . . . , M.

[0045] In certain aspects, the method further comprises forming a mold based on and conforming to the three-dimensional image of the surface of the object.

Brief Description of the Drawings

[0047] Figure 1A and Figure 1B Each schematically illustrates a device according to an embodiment.

[0048] Figure 2 A controller of the device according to an embodiment is schematically shown.

[0049] Figure 3A A cross-sectional view schematically illustrates a radiation detector of an image sensor of the device according to an embodiment.

[0050] Figure 3B A detailed cross-sectional view of the radiation detector according to an embodiment is schematically shown.

[0051] Figure 3C An alternative detailed cross-sectional view of the radiation detector according to an embodiment is schematically shown.

[0052] Figure 4The radiation detector schematically shown in accordance with an embodiment may have a pixel array.

[0053] Figure 5A A top view of a package including the radiation detector and a printed circuit board (PCB) is schematically shown.

[0054] Figure 5B A cross-sectional view of the image sensor is schematically shown, wherein Figure 5A A plurality of the packages are mounted to another printed circuit board.

[0055] Figure 6A and Figure 6B A first mask of the device according to an embodiment is schematically illustrated.

[0056] Figure 6C and Figure 6D A second mask of the device according to an embodiment is schematically illustrated.

[0057] Figure 7 The collimator of the image sensor according to the embodiment is schematically shown.

[0058] Figure 8A The schematic diagram shows that according to an embodiment, an image of an object can be formed by stitching together images of a plurality of different parts of the object.

[0059] Figure 8B The schematic diagram shows that according to an embodiment, an image of an object can be formed by stitching together images of a plurality of different parts of the object.

[0060] Figure 9A- Figure 9C The diagram schematically illustrates an arrangement of the detectors in the image sensor according to an embodiment.

[0061] Figure 10 A hexagonal shaped detector according to an embodiment is schematically shown.

[0062] Figure 11 A flow chart schematically illustrates a method of using the apparatus according to an embodiment.

[0063] Figure 12A and Figure 12B Each schematically shows an embodiment of the Figure 3A 、 Figure 3B and Figure 3C A diagram of the components of the detector's electronic system.

[0064] Figure 13Schematic diagram of the time variation of a current flowing through an electrode of a diode or through an electrical contact of a resistor of a radiation-absorbing layer exposed to radiation (upper curve), the current being caused by charge carriers generated by radiation particles incident on the radiation-absorbing layer, and the corresponding time variation of the electrode voltage (lower curve) according to an embodiment.

[0065] Figure 14 Schematically illustrating an embodiment of the present invention. Figure 13 In an electronic system operating in the manner shown, the temporal variation of the current flowing through the electrode caused by noise (e.g., dark current) (upper curve), and the corresponding temporal variation of the voltage at the electrode (lower curve) are shown.

[0066] Figure 15 Schematically illustrating, according to an embodiment, the temporal variation of a current flowing through an electrode of the radiation absorbing layer exposed to radiation (upper curve), the current caused by carriers generated by radiation particles incident on the radiation absorbing layer, and the corresponding temporal variation of a voltage of the electrode (lower curve), when the electronic system operates to detect incident radiation particles at a higher rate.

[0067] Figure 16 Schematically illustrating an embodiment of the present invention. Figure 15 In an electronic system operating in the manner shown, the temporal variation of the current flowing through the electrode (upper curve) caused by noise (e.g., dark current) and the corresponding temporal variation of the voltage at the electrode (lower curve) are shown.

[0068] Figure 17 Schematically illustrating an embodiment of the present invention. Figure 15 In the electronic system operated in the manner shown, the reset period RST is at time t e Previously expired, the temporal variation of the current flowing through the electrode (upper curve) caused by charge carriers generated by a series of radiation particles incident on the radiation absorbing layer, and the corresponding temporal variation of the voltage of the electrode.

[0069] Figure 18A and Figure 18B A multiple exposure process according to an embodiment is shown.

[0070] Figure 19 Schematic diagram according to an embodiment Figure 18B A simplified side view of the device.

[0071] Figure 20 According to the embodiment, the Figure 19 of the image sensor.

[0072] Figure 21A and Figure 21BAnother multiple exposure process according to an embodiment is schematically illustrated.

[0073] Figure 22 Another flow chart outlining and summarizing the operation of the apparatus according to an embodiment is shown. [Specific implementation method]

[0075] Figure 1A and Figure 1B Each schematically shows an apparatus 10 according to an embodiment. The apparatus 10 comprises a first radiation source 12, a second radiation source 14 and an image sensor 9000. The apparatus 10 may comprise one or more additional radiation sources.

[0076] The first radiation source 12 is configured to generate a first diverging radiation beam 11 towards an object 50. The second radiation source 14 is configured to generate a second diverging radiation beam 13 towards the object 50.

[0077] The image sensor 9000 can capture a partial image of the object 50 using the first divergent radiation beam 11 or the second divergent radiation beam 13. The image sensor 9000, the first radiation source 12, and the second radiation source 14 are configured to rotate around the object 50 about one or more axes, and the relative positions of the image sensor 9000, the first radiation source 12, and the second radiation source 14 are fixed during the rotation around the object 50. The first radiation source 12 and the second radiation source 14 can be mounted on a rigid frame 15.

[0078] According to an embodiment, the first radiation source 12 and the second radiation source 14 may be an X-ray source or a gamma-ray source, respectively. The object 50 may be a person or a container.

[0079] Figure 1A and Figure 1B The first radiation source 12, the second radiation source 14 and the image sensor 9000 are rotated around the object 50 to a certain extent. Figure 1A The first radiation source 12 and Figure 1B The positions of the first radiation source 12, the second radiation source 14 and the image sensor 9000 relative to the object 50 before and after the second radiation source 14 is in the same radiation position relative to the object 50. The image sensor 9000 relative to Figure 1A and Figure 1B The objects 50 in FIG. 5 are at different positions.

[0080] The first radiation source 12 is Figure 1A is activated and the first divergent radiation beam 11 is directed towards the object 50. Figure 1AThe image sensor 9000 in the image sensor can capture an image of a portion of the object 50 with the divergent radiation beam 11.

[0081] The second radiation source 14 is Figure 1B is activated and the second divergent radiation beam 13 is directed towards the object 50. Figure 1B The image sensor 9000 in the image sensor 9000 can capture another partial image of the object 50 with the divergent radiation beam 11.

[0082] According to an embodiment, the apparatus 10 may include a shutter 22 as shown in FIG1 . The shutter 22 may be configured to controllably block the first divergent radiation beam 11 from reaching the object 50, and controllably block the second divergent radiation beam 13 from reaching the object 50. The shutter 22 may have one or more openings. The shutter 22 may have a fixed position relative to the first radiation source 12, the second radiation source 14, and the image sensor 9000. That is, the shutter 22 may rotate relative to the object 50 along with the first radiation source 12, the second radiation source 14, and the image sensor 9000.

[0083] According to an embodiment, the apparatus 10 may include: Figure 2 A controller 20 is schematically shown. The controller 20 is configured to activate and deactivate the first radiation source 12 independently of the second radiation source 14, and to activate and deactivate the second radiation source 14 independently of the first radiation source 12. Activating a radiation source may involve causing it to generate radiation, and deactivating a radiation source may involve causing it not to generate radiation. The controller 20 may be electrically connected to the first radiation source 12 and the second radiation source 14. In an example, the controller 20 activates and deactivates the first radiation source 12 and the second radiation source 14 by starting and stopping power to the first radiation source 12 and the second radiation source 14, respectively.

[0084] The image sensor 9000 may include a plurality of radiation detectors 100. The radiation detectors 100 may be spaced apart from each other. Figure 3A A cross-sectional view schematically illustrates a radiation detector 100 of an image sensor 9000 according to an embodiment. The radiation detector 100 may include a radiation absorbing layer 110 and an electronics layer 120 (e.g., an application-specific integrated circuit) for processing or analyzing an electrical signal generated in the radiation absorbing layer 110 in response to incident radiation. In embodiments, the radiation detector 100 does not include a scintillator. The radiation absorbing layer 110 may include a semiconductor material such as silicon, germanium, gallium arsenide, cadmium telluride, cadmium zinc telluride, or a combination thereof. Such semiconductors may have a high mass attenuation coefficient for radiation generated by the radiation source in the device 10.

[0085] like Figure 3B As shown in the detailed cross-sectional view of the radiation detector 100 according to an embodiment, the radiation absorbing layer 110 may include one or more diodes (e.g., pin or pn) composed of one or more discrete regions 114 of a first doping region 111 and a second doping region 113. The second doping region 113 may be separated from the first doping region 111 by an optional intrinsic region 112. In an embodiment, the discrete regions 114 are separated from each other by the first doping region 111 or the intrinsic region 112. The first doping region 111 and the second doping region 113 have opposite types of doping (e.g., the first doping region 111 is p-type and the second doping region 113 is n-type, or the first doping region 111 is n-type and the second doping region 113 is p-type). Figure 3B In the example in , each discrete region 114 of the second doped region 113 forms a diode together with the first doped region 111 and the optional intrinsic region 112. Figure 3B In the example in FIG, the radiation absorbing layer 110 includes a plurality of diodes having the first doping region 111 as a common electrode. The first doping region 111 may also have discrete portions.

[0086] When a radiation particle from the radiation source strikes the radiation absorbing layer 110, which includes a diode, the radiation particle may be absorbed and generate one or more charge carriers through several mechanisms. A single radiation particle may generate 10 to 100,000 charge carriers. These charge carriers may drift to one of the diode electrodes under an electric field. The electric field may be an external electric field. The electrical contact 119B may include discrete portions, each of which is electrically connected to a discrete region 114. In embodiments, the charge carriers may drift in different directions, such that the charge carriers generated by a single radiation particle are substantially unshared by two different discrete regions 114 ("substantially unshared" here means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a discrete region 114 different from the remaining charge carriers). Charge carriers generated by radiation particles incident around the footprint of one of the discrete regions 114 are substantially unshared by the other discrete region 114. A pixel 150 (also referred to as a sensing element) associated with a discrete region 114 may be a region surrounding the discrete region 114, wherein substantially all (more than 98%, more than 99.5%, more than 99.9%, or more than 99.99%) of the charge carriers generated by incident radiation particles flow toward the discrete region 114. That is, less than 2%, less than 1%, less than 0.1%, or less than 0.01% of the charge carriers flow outside the pixel.

[0087] like Figure 3CAs shown in an alternative detailed cross-sectional view of the radiation detector 100 according to an embodiment, the radiation absorbing layer 110 may include a resistor, but not a diode, made of a semiconductor material such as silicon, germanium, gallium arsenide, cadmium telluride, cadmium zinc telluride, or a combination thereof. The semiconductor may have a high mass attenuation coefficient for radiation generated by the radiation source in the device 10.

[0088] When a radiation particle strikes the radiation-absorbing layer 110, which includes a resistor but no diode, the radiation particle may be absorbed and generate one or more charge carriers through several mechanisms. A single radiation particle may generate 10 to 100,000 charge carriers. These charge carriers may drift to the electrical contact 119A and the electrical contact 119B under an electric field. The electric field may be an external electric field. The electrical contact 119B includes discrete portions. In embodiments, the charge carriers may drift in different directions such that the charge carriers generated by a single radiation particle are substantially unshared by two different discrete portions of the electrical contact 119B ("substantially unshared" herein means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a discrete portion different from the remaining charge carriers). Charge carriers generated by a radiation particle incident around the footprint of one of the discrete portions of the electrical contact 119B are substantially unshared by the other discrete portion of the electrical contact 119B. A pixel 150 associated with a discrete portion of the electrical contact 119B may be a region surrounding the discrete portion in which substantially all (greater than 98%, greater than 99.5%, greater than 99.9%, or greater than 99.99%) of the charge carriers generated by incident radiation particles flow toward the discrete portion of the electrical contact 119B. That is, less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow outside the pixel associated with the discrete portion of the electrical contact 119B.

[0089] The electronic device layer 120 may include an electronic system 121 that is suitable for processing or interpreting signals generated by radiation particles incident on the radiation absorbing layer 110. The electronic system 121 may include analog circuits such as filter networks, amplifiers, integrators and comparators, or digital circuits such as microprocessors and memories. The electronic system 121 may include components shared by multiple pixels or dedicated to a single pixel. For example, the electronic system 121 may include a microprocessor shared between all the pixels and an amplifier dedicated to each pixel. The electronic system 121 is electrically connected to the pixels via through-holes 131. The space between the through-holes may be filled with a filling material 130 to increase the mechanical stability of the connection between the electronic device layer 120 and the radiation absorbing layer 110. Other bonding technologies may be able to connect the electronic system 121 to the pixels without using through-holes.

[0090] Figure 4 The radiation detector 100 schematically illustrates an array of pixels 150. The array can be a rectangular array, a honeycomb array, a hexagonal array, or any other suitable array. Each pixel 150 can be configured to detect radiation particles incident thereon, measure the energy of the radiation particles, or both. For example, each pixel 150 can be configured to count the number of radiation particles incident thereon with energies falling into multiple bins over a period of time. All pixels 150 can be configured to count the number of radiation particles incident thereon with energies falling into multiple bins over the same period of time. Each pixel 150 can have its own analog-to-digital converter (ADC) configured to digitize an analog signal representing the energy of the incident radiation particles into a digital signal. The ADC can have a resolution of 10 bits or higher. Each pixel 150 can be configured to measure its dark current, for example, before or simultaneously with each radiation particle incident thereon. Each pixel 150 can be configured to subtract the contribution of the dark current from the energy of the radiation particles incident thereon. The pixels 150 can be configured to operate in parallel. For example, while one pixel 150 is measuring an incoming radiation particle, another pixel 150 may be waiting for a radiation particle to arrive. The pixels 150 may, but need not, be individually addressable.

[0091] The radiation detectors of the image sensor 9000 may be arranged in any suitable pattern. Figure 5A and Figure 5B An example of the arrangement of radiation detectors in the image sensor 9000 is shown. One or more radiation detectors 100 may be mounted on a printed circuit board (PCB) 400. The term "PCB" as used herein is not limited to a specific material. For example, a PCB may include a semiconductor. The radiation detectors 100 are mounted on the PCB 400. For clarity, the wiring between the radiation detectors 100 and the PCB 400 is not shown. The PCB 400 and the radiation detectors 100 mounted thereon may be referred to as a package 200. The PCB 400 may have areas not covered by the radiation detectors 100 (for example, areas for accommodating bonding wires 410). Each radiation detector 100 may have an active area 190, where the pixels 150 are located. Each radiation detector 100 may have a peripheral area 195 near its edge. This peripheral area 195 does not have pixels and does not detect radiation particles incident thereon.

[0092] Figure 5BThe schematic diagram shows that the image sensor 9000 may include a system PCB 450 on which multiple packages 200 are mounted. The image sensor 9000 may include one or more such system PCBs 450. Electrical connections between the PCB 400 in the package 200 and the system PCB 450 may be achieved via bonding wires 410. To accommodate the bonding wires 410 on the PCB 400, the PCB 400 has an area 405 not covered by the radiation detector 100. To accommodate the bonding wires 410 on the system PCB 450, gaps are provided between the packages 200. The active area 190 of the radiation detector 100 in the image sensor 9000 is collectively referred to as the active area of ​​the image sensor 9000. Other areas of the image sensor 9000 where incident radiation cannot be detected by the image sensor 9000, such as the peripheral area 195, the area 405, or the gaps between the packages 200, are collectively referred to as the blind area of ​​the image sensor 9000.

[0093] Figure 6A and Figure 6B The schematic diagram shows that the device 10 may have a first mask 26. According to an embodiment, the first mask 26 may have a plurality of radiation-transmitting areas 2602 and a radiation-blocking area 2604. Figure 6B The schematic diagram shows that according to an embodiment, the radiation blocking area 2604 is configured to block a portion of the first divergent radiation beam 11, which would otherwise pass through the object 50 and be incident on the blind area 9004 of the image sensor 9000, and the radiation transmitting area 2602 is configured to transmit at least a portion of the first divergent radiation beam 11 that would be incident on the active area 9002 of the image sensor 9000.

[0094] According to an embodiment, the first mask 26 may be made of a material such as lead. The radiation-transmitting region 2602 of the first mask 26 may be a plurality of holes. The radiation-blocking region of the first mask 26 may be an area other than those holes.

[0095] According to an embodiment, the first mask 26 may be located between the first radiation source 12 and the object 50. The first mask 26 may reduce a dose of radiation received by the object 50.

[0096] Figure 6C and Figure 6D The schematic diagram shows that the device 10 may have a second mask 28. According to an embodiment, the second mask 28 may have a plurality of radiation-transmitting areas 2802 and a radiation-blocking area 2804. Figure 6DThe schematic diagram shows that according to an embodiment, the radiation blocking area 2804 is configured to block a portion of the second divergent radiation beam 13, which would otherwise pass through the object 50 and be incident on the blind area 9004 of the image sensor 9000, and the radiation transmitting area 2802 is configured to transmit at least a portion of the second divergent radiation beam 13 that would be incident on the active area 9002 of the image sensor 9000.

[0097] According to an embodiment, the second mask 28 may be made of a material such as lead. The radiation-transmitting region 2802 of the second mask 28 may be a plurality of holes. The radiation-blocking region of the second mask 28 may be an area other than those holes.

[0098] According to an embodiment, the second mask 28 may be located between the second radiation source 14 and the object 50. The second mask 28 may reduce the dose of radiation received by the object 50.

[0099] Figure 7 The schematic diagram shows that an image sensor 9000 according to an embodiment may include a collimator 2000. The collimator 2000 includes a plurality of radiation-transmitting regions 2002 and radiation-blocking regions 2004. The radiation-blocking regions 2004 substantially block radiation that would otherwise be incident on the blind region 9004 of the image sensor 9000, while the radiation-transmitting regions 2002 allow at least a portion of radiation that would otherwise be incident on the active region 9002 of the image sensor 9000 to pass through. The radiation-transmitting regions 2002 may be holes passing through the collimator 2000, and the remaining portions of the collimator 2000 may function as the radiation-blocking regions 2004. The collimator 2000 may be positioned proximate to the image sensor 9000. The size or position of the radiation-transmitting regions 2002 may differ slightly from the size or position of the active region 9002 of the image sensor 9000.

[0100] like Figure 8A As shown in the schematic diagram, when the image sensor 9000, the first radiation source 12 and the second radiation source 14 are Figure 1A As shown, when located at a corresponding position relative to the object 50 , the image sensor 9000 uses the first divergent radiation beam 11 to capture a partial image 51A of a portion of the object 50 .

[0101] The image sensor 9000, the first radiation source 12 and the second radiation source 14 are rotated together relative to the object 50 to a position as shown in FIG. Figure 1B Their respective positions relative to the object 50 are shown, wherein the image sensor 9000 captures a partial image 51B of another portion of the object 50 using the second divergent radiation beam 13 .

[0102] Then, the image sensor 9000 forms a stitched image of the object 50 by stitching the partial image 51A and the partial image 51B. The partial image 51A and the partial image 51B may partially overlap to facilitate stitching.

[0103] According to an embodiment, the apparatus 10 may comprise more than two radiation sources. Figure 8B The schematic diagram shows an example in which the apparatus 10 has three radiation sources. The image sensor 9000 uses divergent radiation beams of radiation from the three radiation sources to capture three partial images 52A, 52B, and 52C of different portions of the object 50 at three different positions A, B, and C relative to the object 50. The image sensor 9000 forms a stitched image of the object 50 by stitching the partial images 52A, 52B, and 52C. The partial images 52A, 52B, and 52C may partially overlap to facilitate stitching. The radiation sources may be staggered, i.e., not arranged along a straight line.

[0104] The radiation detectors 100 can be arranged in the image sensor 9000 in various ways. Figure 9A schematically illustrates an arrangement according to an embodiment, in which the radiation detectors 100 are arranged in staggered rows. For example, radiation detectors 100A and 100B are in the same row, aligned in the Y direction, and have uniform size; radiation detectors 100C and 100D are in the same row, aligned in the Y direction, and have uniform size. Radiation detectors 100A and 100B are staggered in the X direction relative to radiation detectors 100C and 100D. According to an embodiment, the distance X2 between two adjacent radiation detectors 100A and 100B in the same row is greater than the width X1 (i.e., the X-dimension, i.e., the direction in which the row extends) of a radiation detector in the same row and less than twice the width X1. The radiation detectors 100A and 100E are in the same column, aligned in the X direction, and have uniform size; the distance Y2 between two adjacent radiation detectors 100A and 100E in the same column is less than the width Y1 (i.e., the Y direction dimension) of a radiation detector in the same column.

[0105] FIG9B schematically illustrates another arrangement according to an embodiment, in which the radiation detectors 100 are arranged in a rectangular grid. For example, the radiation detectors 100 may include radiation detectors 100A, 100B, 100E, and 100F arranged exactly as in FIG9A , without radiation detectors 100C, 100D, 100G, or 100H as in FIG9A .

[0106] Other arrangements are possible. For example, Figure 9CIn the embodiment, the radiation detector 100 may span the entire width of the image sensor 9000 in the X direction, and the distance Y2 between two adjacent radiation detectors 100 is less than the width Y1 of one radiation detector.

[0107] According to an embodiment, the radiation sources (eg, 12 and 14 ) and the image sensor 9000 may be rotated together around the object about multiple axes.

[0108] The radiation detector 100 in the image sensor 9000 has any suitable size and shape. Figure 9C ), at least some of the radiation detectors 100 are rectangular in shape. According to an embodiment, as Figure 10 As shown, at least some of the radiation detectors are hexagonal in shape. In such radiation detectors, the radiation detectors and the corresponding collimators may have the same shape.

[0109] Figure 11 A flowchart 1100 schematically illustrates the method according to an embodiment. In step 1210, the first radiation source 12 is positioned at a relative radiation position relative to the object 50. In step 1220, the first divergent radiation beam 11 is directed toward the object 50. In step 1230, a partial image of a first portion of the object 50 is captured using the image sensor 9000 and the first divergent radiation beam 11. In step 1240, the second radiation source 14 is positioned at the same relative radiation position relative to the object 50. In step 1250, the second divergent radiation beam 13 is directed toward the object 50. In step 1260, a partial image of a second portion of the object 50 is captured using the image sensor 9000 and the second divergent radiation beam 13. In step 1270, a stitched image of the object 50 is formed by stitching the partial images of the first portion and the partial images of the second portion. Because the relative positions between the image sensor 9000, the first radiation source 12 and the second radiation source 14 are fixed, positioning the first radiation source 12 in step 1210 also results in positioning the second radiation source 14 and the image sensor 9000, and positioning the second radiation source 14 in step 1240 also causes positioning of the first radiation source 12 and the image sensor 9000.

[0110] When the first radiation source 12 is not in the relative radiation position, the radiation generated by the first radiation source 12 can be blocked from reaching the object 50, and when the second radiation source 14 is not in the relative radiation position, the radiation generated by the second radiation source 14 can be blocked from reaching the object 50. For example, the shutter 22 can be used to block the radiation.

[0111] The first radiation source 12 may remain deactivated when it is not in the relative radiation position, and the second radiation source 14 may be deactivated when it is not in the relative radiation position.

[0112] Figure 12A and Figure 12B Each of the diagrams shows a component of an electronic system 121 according to an embodiment. The electronic system 121 may include a first voltage comparator 301 , a second voltage comparator 302 , a counter 320 , a switch 305 , a voltmeter 306 , and a controller 310 .

[0113] The first voltage comparator 301 is configured to compare the voltage of an electrode of the diode 300 with a first threshold. The diode can be formed by the first doped region 111, one of the discrete regions 114 of the second doped region 113, and the optional intrinsic region 112. Alternatively, the first voltage comparator 301 can be configured to compare the voltage of an electrical contact (e.g., a discrete portion of the electrical contact 119B) with a first threshold. The first voltage comparator 301 can be configured to directly monitor the voltage or calculate the voltage by integrating the current flowing through the diode or electrical contact over a period of time. The first voltage comparator 301 can be controllably activated or deactivated by the controller 310. The first voltage comparator 301 can be a continuous comparator. That is, the first voltage comparator 301 can be configured to be continuously activated and monitor the voltage. Configuring the first voltage comparator 301 as a continuous comparator reduces the chance that the system 121 will miss a signal generated by an incident radiation particle. Configuring the first voltage comparator 301 as a continuous comparator is particularly suitable when the incident radiation intensity is relatively high. The first voltage comparator 301 can be a clocked comparator, which has the advantage of lower power consumption. Configuring the first voltage comparator 301 as a clocked comparator prevents the system 121 from missing signals generated by some incident radiation particles. When the incident radiation intensity is low, the chance of missing an incident radiation particle is low because the time interval between two consecutive radiation particles is relatively long. Therefore, configuring the first voltage comparator 301 as a clocked comparator is particularly suitable when the incident radiation intensity is relatively low. The first threshold value can be 5-10%, 10-20%, 20-30%, 30-40%, or 40-50% of the maximum voltage generated by an incident radiation particle in the diode or resistor. The maximum voltage can depend on the energy of the incident radiation particle (i.e., the wavelength of the incident radiation), the material of the radiation absorbing layer 110, and other factors. For example, the first threshold value can be 50mV, 100mV, 150mV, or 200mV.

[0114] The second voltage comparator 302 is configured to compare the voltage with a second threshold. The second voltage comparator 302 can be configured to directly monitor the voltage or calculate the voltage by integrating the current flowing through the diode or electrical contact over a period of time. The second voltage comparator 302 can be a continuous comparator. The second voltage comparator 302 can be controllably enabled or disabled by the controller 310. When the second voltage comparator 302 is disabled, the power consumption of the second voltage comparator 302 can be less than 1%, less than 5%, less than 10%, or less than 20% of the power consumption when the second voltage comparator 302 is enabled. The absolute value of the second threshold is greater than the absolute value of the first threshold. As used herein, the term "absolute value" or "modulus" of a real number x, |x|, is the non-negative value of x, regardless of its sign. That is, if x ≥ 0, |x| = x, and if x < 0, |x| = -x. The second threshold can be 200%-300% of the first threshold. The second threshold value is at least 50% of the maximum voltage of an incident radiation particle generated in the diode or the resistor. For example, the second threshold value can be 100mV, 150mV, 200mV, 250mV, or 300mV. The second voltage comparator 302 and the first voltage comparator 301 can be the same component. That is, the system 121 can have a voltage comparator that can compare the voltage with two different threshold values ​​at different times.

[0115] The first voltage comparator 301 or the second voltage comparator 302 may include one or more operational amplifiers or any other suitable circuits. The first voltage comparator 301 or the second voltage comparator 302 may have a high speed to allow the system 121 to operate at a high flux of high incident radiation. However, having high speed generally comes at the expense of power consumption.

[0116] The counter 320 is configured to record a number of radiation particles reaching the diode or the resistor. The counter 320 can be a software component (eg, a number stored in a computer memory) or a hardware component (eg, a 4017 IC and a 7490 IC).

[0117] The controller 310 can be a hardware component such as a microcontroller or microprocessor. The controller 310 is configured to initiate a time delay from the time the first voltage comparator 301 determines that the absolute value of the voltage equals or exceeds the absolute value of the first threshold (e.g., when the absolute value of the voltage increases from below the absolute value of the first threshold to equal or exceed the absolute value of the first threshold). The absolute value is used here because the voltage can be negative or positive, depending on whether the voltage at the cathode or anode of the diode is used or which electrical contact is used. The controller 310 can be configured to disable the second voltage comparator 302, the counter 320, and any other circuitry not required for the operation of the first voltage comparator 301 until the first voltage comparator 301 determines that the absolute value of the voltage equals or exceeds the absolute value of the first threshold. The time delay can expire before or after the voltage becomes stable (i.e., the rate of change of the voltage is substantially zero). The phrase "rate of change is substantially zero" means that the temporal rate of change of the voltage is less than 0.1% / ns. The phrase "substantially non-zero rate of change" means that the temporal rate of change of the voltage is at least 0.1% / ns.

[0118] The controller 310 may be configured to activate the second voltage comparator during the time delay (including both its onset and expiration). In an embodiment, the controller 310 is configured to activate the second voltage comparator at the start of the time delay. The term "activate" means placing a component into an operational state (e.g., by sending a signal such as a voltage pulse or logic level, by providing power, etc.). The term "deactivate" means placing a component into a non-operating state (e.g., by sending a signal such as a voltage pulse or logic level, by cutting off power, etc.). The operational state may have higher power consumption than the non-operating state (e.g., 10 times higher, 100 times higher, or 1000 times higher). The controller 310 itself may be deactivated until the output of the first voltage comparator 301 equals or exceeds the absolute value of the first threshold value, thereby activating the controller 310.

[0119] If the second voltage comparator 302 determines that the absolute value of the voltage is equal to or exceeds the absolute value of the second threshold during the time delay, the controller 310 may be configured to increase the number recorded by the counter 320 by one.

[0120] The controller 310 can be configured to cause the voltmeter 306 to measure the voltage upon expiration of the time delay. The controller 310 can be configured to connect the electrode to electrical ground to reset the voltage and discharge any carriers accumulated on the electrode. In an embodiment, the electrode is connected to electrical ground after the time delay has expired. In an embodiment, the electrode is connected to electrical ground for a limited reset period. The controller 310 can connect the electrode to the electrical ground by controlling the switch 305. The switch can be a transistor, such as a field effect transistor (FET).

[0121] In an embodiment, the system 121 is free of analog filter networks (eg, RC networks). In an embodiment, the system 121 is free of analog circuits.

[0122] The voltmeter 306 may feed the measured voltage to the controller 310 in the form of an analog or digital signal.

[0123] The system 121 may include an integrator 309 electrically connected to the electrode or electrical contact of the diode 300, wherein the integrator is configured to collect carriers from the electrode. The integrator may include a capacitor in the feedback path of the amplifier. An amplifier configured in this manner is called a capacitive transimpedance amplifier (CTIA). A capacitive transimpedance amplifier has a high dynamic range by preventing the amplifier from saturating and improves the signal-to-noise ratio by limiting the bandwidth in the signal path. The carriers from the electrode are collected over a period of time ("integration period") (e.g., Figure 13 As shown, the voltage is accumulated on the capacitor between time t0 and time t1, or between time t1 and time t2. After the integration period expires, the capacitor voltage is sampled and then reset by a reset switch. The integrator may include a capacitor directly connected to the electrode.

[0124] Figure 13The diagram schematically illustrates the temporal variation of the current flowing through the electrode (upper curve) caused by carriers generated by radiation particles incident on the diode or resistor, and the corresponding temporal variation of the voltage at the electrode (lower curve). The voltage may be the integral of the current with respect to time. At time t0, the radiation particle strikes the diode or resistor, carriers begin to be generated in the diode or resistor, current begins to flow through the electrode of the diode or resistor, and the absolute value of the voltage at the electrode or electrical contact begins to increase. At time t1, the first voltage comparator 301 determines that the absolute value of the voltage equals or exceeds the absolute value of the first threshold V1. The controller 310 initiates time delay TD1 and may deactivate the first voltage comparator 301 at the start of TD1. If the controller 310 was deactivated before time t1, it is activated at time t1. During TD1, the controller 310 activates the second voltage comparator 302. As used herein, the term "during" a time delay refers to the start and end (i.e., end) of the time delay, and any time in between. For example, the controller 310 may activate the second voltage comparator 302 when the TD1 expires. If the second voltage comparator 302 determines during the TD1 that the absolute value of the voltage at time t2 is equal to or exceeds the absolute value of the second threshold, the controller 310 increases the number recorded by the counter 320 by one. e , all carriers generated by the radiation particles drift out of the radiation absorbing layer 110. At time t s , the time delay TD1 expires. Figure 13 In the example, time t s At time t e After that, TD1 expires after all carriers generated by the radiation particles drift out of the radiation absorbing layer 110. At time t s The rate of change of the voltage is thus substantially zero. The controller 310 may be configured to disable the second voltage comparator 302 upon expiration of TD1 or at time t2, or any time in between.

[0125] The controller 310 may be configured to cause the voltmeter 306 to measure the voltage when the time delay TD1 expires. In an embodiment, the controller 310 causes the voltmeter 306 to measure the voltage after the time delay TD1 expires and the rate of change of the voltage becomes substantially zero. The voltage at this time is proportional to the number of carriers generated by the radiation particle, and the number of carriers is related to the energy of the radiation particle. The controller 310 may be configured to determine the energy of the radiation particle based on the voltage measured by the voltmeter 306. One method of determining the energy is by binning the voltage. The counter 320 may have a sub-counter for each bin. When the controller 310 determines that the energy of the radiation particle falls into a bin, the controller 310 may increase the number recorded in the sub-counter for that bin by one. Thus, the system 121 is capable of detecting radiation patterns and resolving the radiation energy of each radiation particle.

[0126] After TD1 expires, the controller connects the electrode to electrical ground for a reset period RST to allow the carriers accumulated on the electrode to flow to ground and reset the voltage. After RST, the system 121 is ready to detect another incident radiation particle. Implicitly, Figure 13 In the example shown in FIG1 , the rate of incident radiation particles that the system 121 can process is limited to 1 / (TD1 + RST). If the first voltage comparator 301 is disabled, the controller 310 can activate it at any time before the expiration of RST. If the controller 310 is disabled, it can be activated before the expiration of RST.

[0127] Figure 14 Schematically shown in Figure 13The system 121 operating in the manner shown shows temporal variations in the current flowing through the electrode (upper curve) caused by noise (e.g., dark current, background radiation, scattered radiation, fluorescent radiation, shared charge from adjacent pixels), and the corresponding temporal variations in the voltage across the electrode (lower curve). At time t0, the noise begins. If the noise is not sufficiently large to cause the absolute value of the voltage to exceed the absolute value of V1, the controller 310 does not activate the second voltage comparator 302. If the noise is sufficiently large (as determined by the first voltage comparator 301) to cause the absolute value of the voltage to exceed the absolute value of V1 at time t1, the controller 310 activates time delay TD1 and may deactivate the first voltage comparator 301 at the beginning of TD1. During TD1 (e.g., at the expiration of TD1), the controller 310 activates the second voltage comparator 302. It is highly unlikely that the noise will be large enough to cause the absolute value of the voltage to exceed the absolute value of V2 during TD1. Therefore, the controller 310 does not increase the number recorded by the counter 320. e , the noise ends. At time t s , the time delay TD1 expires. The controller 310 can be configured to deactivate the second voltage comparator 302 upon expiration of TD1. If the absolute value of the voltage does not exceed the absolute value of V2 during TD1, the controller 310 can be configured to prevent the voltmeter 306 from measuring the voltage. After TD1 expires, the controller 310 connects the electrode to electrical ground for a reset period RST to allow carriers accumulated on the electrode due to noise to flow to ground and reset the voltage. Therefore, the system 121 can effectively suppress noise.

[0128] Figure 15The schematic diagram shows the temporal variation of the current flowing through the electrode (upper curve) caused by carriers generated by the radiation particles incident on the diode or resistor, and the corresponding temporal variation of the voltage at the electrode (lower curve) when the system 121 is operating to detect radiation particles incident at a rate greater than 1 / (TD1 + RST). The voltage may be the integral of the current with respect to time. At time t0, the radiation particle strikes the diode or resistor, carriers begin to be generated in the diode or resistor, current begins to flow through the diode electrode or the resistor electrical contact, and the absolute value of the voltage at the electrode or electrical contact begins to increase. At time t1, the first voltage comparator 301 determines that the absolute value of the voltage equals or exceeds the absolute value of the first threshold V1. The controller 310 initiates a time delay TD2 that is shorter than TD1. The controller 310 may deactivate the first voltage comparator 301 at the start of TD2. If the controller 310 was deactivated before time t1, it is activated at time t1. During TD2 (e.g., when TD2 expires), the controller 310 activates the second voltage comparator 302. If during TD2, the second voltage comparator 302 determines that the absolute value of the voltage is equal to or exceeds the absolute value of the second threshold at time t2, the controller 310 increases the number recorded by the counter 320 by one. e , all carriers generated by the radiation particles drift outside the radiation absorbing layer 110. At time t h , the time delay TD2 expires. Figure 15 In the example, time t h At time t e That is, TD2 expires before all carriers generated by the radiation particles drift out of the radiation absorbing layer 110. Therefore, the rate of change of the voltage at time t h The controller 310 may be configured to disable the second voltage comparator 302 upon expiration of TD2 or at time t2, or any time therebetween.

[0129] The controller 310 may be configured to infer the voltage at time t from the voltage as a function of time during TD2. e and using the inferred voltage to determine the energy of the radiated particle.

[0130] After TD2 expires, the controller 310 connects the electrode to electrical ground for a reset period RST to allow carriers accumulated on the electrode to flow to ground and reset the voltage. In an embodiment, RST is at time t eThe rate of change of the voltage may be substantially non-zero after RST because all carriers generated by the radiation particle are at time t e The voltage has not drifted out of the radiation absorbing layer 110 when the previous RST period expires. The rate of change of the voltage at time t e becomes approximately zero after that, and the voltage at time t e Then it stabilizes at the residual voltage VR. In the embodiment, RST is at time t e or expires after time t, and the rate of change of the voltage may be substantially zero after RST, since all carriers generated by the radiation particles are e Drift out of the radiation absorbing layer 110. After the RST, the system 121 is ready to detect another incident radiation particle. If the first voltage comparator 301 has been disabled, the controller 310 can activate it at any time before the RST expires. If the controller 310 has been disabled, it can be activated before the RST expires.

[0131] Figure 16 Schematically shown in Figure 15 The system 121 operating in the manner shown shows temporal variations in the current flowing through the electrode (upper curve) caused by noise (e.g., dark current, background radiation, scattered radiation, fluorescent radiation, shared charge from adjacent pixels), and the corresponding temporal variations in the voltage across the electrode (lower curve). At time t0, the noise begins. If the noise is not sufficiently large to cause the absolute value of the voltage to exceed the absolute value of V1, the controller 310 does not activate the second voltage comparator 302. If the noise is sufficient to cause the absolute value of the voltage to exceed the absolute value of V1 at time t1, as determined by the first voltage comparator 301, the controller 310 activates time delay TD2 and may deactivate the first voltage comparator 301 at the start of TD2. During TD2 (e.g., at the expiration of TD2), the controller 310 activates the second voltage comparator 302. It is highly unlikely that the noise will be large enough to cause the absolute value of the voltage to exceed the absolute value of V2 during TD2. Therefore, the controller 310 does not increase the number recorded by the counter 320. e , the noise ends. At time t h , the time delay TD2 expires. The controller 310 can be configured to deactivate the second voltage comparator 302 upon expiration of TD2. After TD2 expires, the controller 310 connects the electrode to electrical ground for a reset period RST to allow carriers accumulated on the electrode due to noise to flow to ground and reset the voltage. Therefore, the system 121 can effectively suppress noise.

[0132] Figure 17 Schematically, in Figure 15 In the system 121 operated in the manner, RST at time t e The time variation of the current flowing through the electrode (upper curve) caused by the carriers generated by a series of radiation particles incident on the diode or resistor before the expiration of the time period, and the corresponding time variation of the voltage of the electrode (lower curve). The voltage curve caused by the carriers generated by each incident radiation particle is offset by the residual voltage before the radiation particle. The absolute value of the residual voltage increases continuously with each incident particle. When the absolute value of the residual voltage exceeds V1 (see Figure 17 ), the controller initiates time delay TD2, and the controller 310 may deactivate the first voltage comparator 301 at the start of TD2. If no further radiation particles impinge on the diode or the resistor during TD2, the controller connects the electrodes to electrical ground during a reset period RST at the end of TD2, thereby resetting the residual voltage. Therefore, the residual voltage does not cause the number recorded by the counter 320 to increase.

[0133] Reference Figure 1A and Figure 1B ,like Figure 1A The object 50 is shown as being imaged by a first exposure of the first divergent radiation beam 11, and as shown Figure 1B The second exposure of the object 50 to the second divergent radiation beam to form an image may be generally referred to as Figure 1A and Figure 1B Typically, a multiple exposure process may include N exposures, where N is an integer greater than 1. For example, Figure 1A and Figure 1B The multiple exposure process N = 2. For another example, Figure 8B The multiple exposure process has N = 3 (corresponding to 3 partial images 52A, 52B and 52C).

[0134] In an embodiment, Figure 1A and Figure 1B During the multiple exposure process, when the object 50 is stationary relative to a system reference, the image sensor 9000, the first radiation source 12, and the second radiation source 14 may rotate around the object 50. In an embodiment, the system reference may be the Earth. In an embodiment, the object 50 may be a plastic product. In an embodiment, the divergent radiation beams 11 and 13 may be X-rays having a photon energy less than 5 KeV.

[0135] Figure 18A and Figure 18BThe multiple exposure process according to the embodiment is shown. In the embodiment, in addition to Figure 18A and Figure 18B In the multiple exposure process, when the image sensor 9000, the first radiation source 12, and the second radiation source 14 are stationary relative to the reference system, the object 50 may be rotated relative to the image sensor 9000, the first radiation source 12, and the second radiation source 14 (for example, in a clockwise direction as shown in the figure). Figure 18A and Figure 18B The multiple exposure process can be similar to Figure 1A and Figure 1B The multiple exposure process.

[0136] In an embodiment, the rotation of the object 50 may be about a rotation axis perpendicular to a device plane intersecting the image sensor 9000, the first radiation source 12, and the second radiation source 14. Figure 18A and Figure 18B As shown, if the device plane is on or parallel to the drawing page, the rotation axis of the object 50 is perpendicular to the drawing page.

[0137] In an embodiment, the rotation axis of the object 50 is on a line passing through the center of the Earth. In other words, the plane of the device perpendicular to the rotation axis is parallel to the area of ​​the Earth's surface closest to the device 10.

[0138] Figure 19 Schematic diagram according to an embodiment Figure 18B 1910 . Specifically, the apparatus 10 may further include a platform 1910. In an embodiment, the object 50 may be physically fixed to the platform 1910. In other words, the relative position between the object 50 and the platform 1910 is fixed. For example, the object 50 may be tied, attached, or simply placed on the platform 1910. In an embodiment, the platform 1910 may be configured to rotate relative to the image sensor 9000, the first radiation source 12, and the second radiation source 14, thereby rotating the object 50 relative to the image sensor 9000, the first radiation source 12, and the second radiation source 14.

[0139] Figure 20 According to the embodiment, the Figure 19The image sensor 9000 of FIG. Specifically, in an embodiment, the radiation detectors 100 of the image sensor 9000 (e.g., radiation detectors 100X and 100Y) may be arranged on the image sensor 9000 such that their respective radiation receiving surfaces (e.g., radiation receiving surfaces 100X' and 100Y') are not parallel to each other. The radiation receiving surface of the radiation detector 100 is a surface of the radiation detector 100 that is (A) parallel to a pixel plane intersecting all pixels (i.e., sensing elements) 150 of the radiation detector 100 and (B) closest to the pixel plane.

[0140] In an embodiment, for each radiation detector 100 of the image sensor 9000, any straight line passing through the radiation detector 100 and the first radiation source 12 or the second radiation source 14 is substantially perpendicular (i.e., vertical or nearly vertical). Therefore, any radiation particle propagating from any radiation source (12 or 14) to any radiation detector 100 of the image sensor 9000 follows a path that is substantially perpendicular to the receiving surface of the radiation detector 100.

[0141] For example, as referenced Figure 20 The straight line 13X passing through the radiation detector 100X and the second radiation source 14 is substantially perpendicular to the radiation receiving surface 100X' of the radiation detector 100X. Similarly, the straight line 13Y passing through the radiation detector 100Y and the second radiation source 14 is substantially perpendicular to the radiation receiving surface 100Y' of the radiation detector 100Y.

[0142] Figure 21A and Figure 21B Schematically illustrates another multiple exposure process according to an embodiment. In the embodiment, in addition to the relative radiation position 1214.21 relative to the object 50 being different, Figure 21A and Figure 21B The multiple exposure process can be similar to Figure 18A and Figure 18B In the embodiment, the multiple exposure process Figure 18A and Figure 18B The second exposure of the multiple exposure process ( Figure 18B ) After that, the object 50 can be rotated clockwise to Figure 21A Then, as Figure 21A shown Figure 21A and Figure 21BA first exposure of the multiple exposure process may be performed (i.e. using the divergent radiation beam 11.21 emitted by the radiation source 12 from the relative radiation position 1214.21 relative to the object 50). Thereafter, in an embodiment, the object 50 may be further rotated clockwise to Figure 21B Then, as Figure 21B shown Figure 21A and Figure 21B A second exposure of the multiple exposure process may be performed (ie using the divergent radiation beam 13 . 21 emitted by the radiation source 14 from the relative radiation position 1214 . 21 relative to the object 50 ).

[0143] As Figure 21A and Figure 21B As a result of the first exposure and the second exposure of the multiple exposure process, two partial images of different parts of the object 50 can be captured. Next, in an embodiment, a stitched image of the object 50 can be formed by stitching these two partial images. Generally, there are M multiple exposure processes with M different relative radiation positions relative to the object 50 (similar to Figure 18A and Figure 18B The multiple exposure process and Figure 21A and Figure 21B The multiple exposure process) can be performed one after another to obtain M stitched images of the object 50 (M is an integer greater than 1).

[0144] Next, in an embodiment, a three-dimensional image of the object surface of the object 50 may be formed based on the M stitched images. Next, in an embodiment, a mold (not shown) may be formed based on and conforming to the three-dimensional image of the object surface of the object 50. Next, in an embodiment, the mold may be used to produce a copy of the object 50.

[0145] Figure 22 A flowchart 2200 is shown that summarizes and generalizes the operation of the apparatus 10 according to an embodiment. In step 2210, the components of the apparatus 10 and the object 50 may be positioned for imaging. Specifically, for i = 1, ..., M, and j = 1, ..., N, a radiation source (j) and the object 50 are positioned such that the radiation source (j) is at the same relative radiation position (i) relative to the object 50. For example, for i = j = 1 ( Figure 18A ), the radiation source (1) (ie, the radiation source 12) is at the same relative radiation position (1) (ie, the relative radiation position 1214.18) relative to the object 50. For another example, for i = 1 and j = 2 ( Figure 18B), the radiation source (2) (ie, the radiation source 14) is at the same relative radiation position (1) (ie, the relative radiation position 1214.18) relative to the object 50.

[0146] In step 2220, the divergent radiation beam is directed toward the object 50. Specifically, when the radiation source (j) is at a relative radiation position (i) relative to the object 50, the divergent radiation beam B ij is directed from the radiation source (j) toward the object 50 .

[0147] For example, for i = j = 1 ( Figure 18A ), when the radiation source (1) is at the relative radiation position (1) (i.e., relative radiation position 1214.18) relative to the object 50, the divergent radiation beam (1, 1) (i.e., divergent radiation beam 11.18) is directed from the radiation source (1) (i.e., radiation source 12) toward the object 50. For another example, for i=1 and j=2 ( Figure 18B ), when the radiation source (2) is in the relative radiation position (1) (i.e., relative radiation position 1214.18) relative to the object 50, the divergent radiation beam (1, 2) (i.e., divergent radiation beam 13.18) is directed from the radiation source (2) (i.e., radiation source 14) toward the object 50.

[0148] In step 2230, partial images of various parts of the object 50 may be captured. Specifically, the partial image P of a part of the object 50 may be captured. ij The divergent radiation beam B ij When being guided toward the object 50 , the image sensor 9000 is used to take a picture.

[0149] For example, for i = j = 1 ( Figure 18A ), can be in the divergent radiation beam B 11 When the divergent radiation beam 11.18 is directed toward the object 50, the image sensor 9000 is used to capture a partial image P of a portion of the object 50. 11 For another example, for i = 1 and j = 2 ( Figure 18B ), can be in the divergent radiation beam B 12 When the divergent radiation beam 13.18 is directed toward the object 50, the image sensor 9000 is used to capture a partial image P of a portion of the object 50. 12 .

[0150] In step 2240, a stitched image may be formed. More specifically, for i = 1, ..., M, the partial images P may be stitched together. ij, j = 1,…, N, to form a stitched image (i) of the object 50.

[0151] For example, for i = 1 ( Figure 18A and Figure 18B ), can be achieved by splicing the partial images P 11 ( Figure 18A ) and the partial image P 12 ( Figure 18B ) to form a stitched image (1) of the object 50. For another example, for i= 2 ( Figure 21A and Figure 21B ), can be achieved by splicing the partial images P 21 ( Figure 21A ) and the partial image P 22 ( Figure 21B ) to form a stitched image (2) of the object 50.

[0152] Next, in an embodiment, a three-dimensional image of the object surface of the object 50 may be formed based on the M stitched images. Then, in an embodiment, a mold may be formed based on and consistent with the three-dimensional image of the object surface of the object 50. Then, in an embodiment, the mold may be used to produce a copy of the object 50.

[0153] In the above and Figure 18A 、 Figure 18B 、 Figure 21A and Figure 21B In a related embodiment, the exposure time sequence of the multiple exposure process is as follows: Figure 18A (or just referred to as Figure 18A ) and then Figure 18B , then Figure 21A , then Figure 21B Generally, the time sequence of the exposures of the multiple exposure processes can be arbitrary. For example, the time sequence of the exposures can be Figure 18B , followed by Figure 18A , followed by Figure 21A , followed by Figure 21B For another example, the time sequence of the exposure can even be Figure 18A , followed by Figure 21B , followed by Figure 18B , followed by Figure 21A .

[0154] Although various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for illustrative purposes only and are not intended to be limiting, and their true scope and spirit should be determined by the claims herein.

Claims

1. An imaging device comprising: a first radiation source configured to generate a first divergent radiation beam directed toward the object; a second radiation source configured to generate a second divergent radiation beam directed toward the object; and Image sensor; wherein the object is configured to rotate relative to the image sensor, the first radiation source, and the second radiation source, and The relative positions among the image sensor, the first radiation source and the second radiation source are fixed. Wherein, the image sensor includes: a plurality of radiation detectors spaced apart from one another, wherein the plurality of radiation detectors respectively include radiation receiving surfaces that are not all parallel to one another, and wherein, for each radiation detector in the plurality of radiation detectors, any straight line passing through the radiation detector and the first radiation source or the second radiation source is substantially perpendicular to the radiation receiving surface of the radiation detector; wherein the image sensor is configured to capture a first partial image of the object by using the radiation detector and the first divergent radiation beam, and is configured to capture a second partial image of the object by using the radiation detector and the second divergent radiation beam; and The image sensor is configured to form an image of the object by stitching the first partial image and the second partial image.

2. The apparatus of claim 1, wherein the image sensor, the first radiation source, and the second radiation source are stationary.

3. The apparatus of claim 1, wherein the first divergent radiation beam and the second divergent radiation beam are X-rays having a photon energy less than 5 KeV.

4. The apparatus of claim 1, wherein the rotation of the object is performed about a rotation axis perpendicular to a plane of the apparatus in which the image sensor, the first radiation source, and the second radiation source are located.

5. The device of claim 1, further comprising a platform, wherein the object is physically fixed to the platform, and The platform is configured to rotate relative to the image sensor, the first radiation source, and the second radiation source.

6. The apparatus of claim 1, further comprising a controller configured to activate and deactivate the first radiation source independently of the second radiation source, and configured to activate and deactivate the second radiation source independently of the first radiation source.

7. The apparatus of claim 1, further comprising a shutter configured to controllably block the first diverging radiation beam from reaching the object and to controllably block the second diverging radiation beam from reaching the object.

8. The apparatus of claim 1, wherein the image sensor is configured to capture a partial image of the object using the first divergent radiation beam or the second divergent radiation beam.

9. The device according to claim 1, wherein the image sensor comprises a collimator having a plurality of radiation-transmitting regions and a radiation-blocking region; The radiation blocking region is configured to block radiation incident on a blind area of ​​the image sensor, and the radiation transmitting region is configured to transmit at least a portion of radiation incident on an active area of ​​the image sensor.

10. The apparatus of claim 1 , further comprising a mask having a plurality of radiation-transmissive regions and a radiation-blocking region; The radiation blocking area is configured to block a portion of the first divergent radiation beam, which would otherwise pass through the object and be incident on a blind area of ​​the image sensor, and the radiation transmitting area is configured to transmit at least a portion of the first divergent radiation beam that would be incident on an active area of ​​the image sensor.

11. The apparatus of claim 1 , wherein when the image sensor captures a first partial image of the object, the first radiation source is located at a first radiation position relative to the object, and when the image sensor captures a second partial image of the object, the second radiation source is located at a second radiation position relative to the object, wherein the first radiation position is the same as the second radiation position.

12. The apparatus of claim 1, wherein at least some of the plurality of radiation detectors are arranged in staggered rows.

13. The device of claim 1 , wherein the sizes of the radiation detectors in the same row are uniform; wherein the distance between two adjacent radiation detectors in the same row is greater than the width of one radiation detector in the same row and less than twice the width in the extension direction of the row.

14. The apparatus of claim 1, wherein at least some of the plurality of radiation detectors are rectangular.

15. The apparatus of claim 1, wherein at least some of the plurality of radiation detectors are hexagonal.

16. The apparatus of claim 1, wherein: at least one radiation detector of the plurality of radiation detectors comprises a radiation absorbing layer and an electronics layer; wherein the radiation absorbing layer comprises an electrode; wherein the electronic device layer includes an electronic system; Wherein, the electronic system includes: a first voltage comparator configured to compare the voltage of the electrode with a first threshold, a second voltage comparator configured to compare the voltage with a second threshold, a counter configured to record the number of radiation particles reaching the radiation absorbing layer, and Controller; wherein the controller is configured to start the time delay from when the first voltage comparator determines that the absolute value of the voltage is equal to or exceeds the absolute value of the first threshold; wherein the controller is configured to enable the second voltage comparator during the time delay; The controller is configured to increase the number of radiation particles recorded by the counter by one if the second voltage comparator determines that the absolute value of the voltage is equal to or exceeds the absolute value of the second threshold.

17. The apparatus of claim 16, wherein the electronic system further comprises an integrator electrically connected to the electrode, wherein the integrator is configured to collect carriers from the electrode.

18. The apparatus of claim 16, wherein the controller is configured to enable the second voltage comparator upon the start or expiration of the time delay.

19. The apparatus of claim 16, wherein the electronic system further comprises a voltmeter, wherein the controller is configured to cause the voltmeter to measure the voltage upon expiration of the time delay.

20. The apparatus of claim 16, wherein the controller is configured to determine the energy of the radiated particle based on the voltage value measured after expiration of the time delay.

21. The apparatus of claim 16, wherein the controller is configured to connect the electrode to electrical ground.

22. The apparatus of claim 16, wherein the rate of change of the voltage is substantially zero upon expiration of the time delay.

23. The apparatus of claim 16, wherein the rate of change of the voltage is substantially non-zero upon expiration of the time delay.

24. An imaging method comprising: For each relative radiation position i among M relative radiation positions, positioning each radiation source j among N radiation sources and the same object so that the radiation source j is at the same relative radiation position i relative to the object, wherein M and N are positive integers, i is a positive integer less than or equal to M, j is a positive integer less than or equal to N, i = 1, ..., M, and j = 1, ..., N; When the radiation source j is at the relative radiation position i relative to the object, the divergent radiation beam B from the radiation source j is ij leading to said object; For the divergent radiation beam B ij , using the same image sensor to capture a partial image P of a portion of the object ij ;and For each relative radiation position i in the M relative radiation positions, by splicing N partial images P ij , forming a stitched image i of the object, wherein said positioning comprises rotating said object relative to said image sensor and said radiation source j, The relative positions between the image sensor and the N radiation sources are fixed, and Where M and N are integers greater than 1, wherein the image sensor includes a plurality of radiation detectors spaced apart from one another, wherein the plurality of radiation detectors respectively include radiation receiving surfaces that are not all parallel to one another, and wherein for each radiation detector of the plurality of radiation detectors, any straight line passing through the radiation detector and any one of the N radiation sources is substantially perpendicular to the radiation receiving surface of the radiation detector, and Wherein, the partial image P of a part of the object is captured ij The method comprises: receiving the divergent radiation beam B having passed through the object by using the radiation detector; ij part of.

25. The method of claim 24, wherein the image sensor and the N radiation sources are stationary.

26. The method of claim 24, wherein the divergent radiation beam B ij It is an X-ray with a photon energy less than 5KeV.

27. The method of claim 24, wherein the rotation of the object is performed about a rotation axis perpendicular to a plane of an apparatus in which the image sensor and the N radiation sources are located.

28. The method of claim 24, wherein the object is physically fixed to the platform, and Wherein rotating the object includes rotating the platform.

29. The method of claim 24, wherein: For each radiation source j among the N radiation sources, when the radiation source j is not at any relative radiation position among the M relative radiation positions, the radiation source j is deactivated.

30. The method of claim 24, wherein: For each radiation source j among the N radiation sources, when the radiation source j is not at any relative radiation position among the M relative radiation positions, the radiation generated by the radiation source j is blocked.

31. The method of claim 24, wherein for the M relative radiation positions and the N radiation sources, each of the divergent radiation beams B ij Those portions of the image sensor that would pass through the object and be incident on the blind area of ​​the image sensor if not blocked are blocked.

32. The method of claim 24, wherein for each relative radiation position i in the M relative radiation positions, the N partial images P ij There is spatial overlap between them.

33. The method of claim 24, further comprising: A three-dimensional image of the surface of the object is formed based on the M stitched images.

34. The method of claim 33, further comprising forming a mold based on and conforming to the three-dimensional image of the surface of the object.

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