CN117940808A

CN117940808A - Imaging method using multiple radiation beams

Info

Publication number: CN117940808A
Application number: CN202180102151.6A
Authority: CN
Inventors: 曹培炎
Original assignee: Shenzhen Xpectvision Technology Co Ltd
Current assignee: Shenzhen Xpectvision Technology Co Ltd
Priority date: 2021-09-16
Filing date: 2021-09-16
Publication date: 2024-04-26
Also published as: WO2023039774A1; TW202314291A

Abstract

A method is disclosed herein. The method comprises the following steps: transmitting M bombardment beams (i), i=1, … …, M) (712 a) to target points (720 a, 720b, 720 c) (i) on the target (725), i=1, … …, M, respectively, resulting in radiation beams (722 a) (i), i=1, … …, M) emitted from the target points (i), i=1, … …, M, respectively, and propagating towards the object (730), wherein M is an integer greater than 1; and for each value of i, obtaining a 2D (two-dimensional) image (i) of the object (730) using radiation of the radiation beam (i) that has passed through the object (730), wherein the target (725) is stationary with respect to the object (730).

Description

Imaging method using multiple radiation beams

[ Background Art ]

A radiation detector is a device that measures radiation properties. Examples of properties may include the spatial distribution of intensity, phase and polarization of the radiation. The radiation may be radiation that has interacted with the object. For example, the radiation measured by the radiation detector may be radiation that has penetrated the object. The radiation may be electromagnetic radiation, such as infrared light, visible light, ultraviolet light, X-rays or gamma rays. The radiation may also be of other types, such as alpha rays and beta rays. The imaging system may include one or more image sensors, each of which may have a plurality of radiation detectors.

[ Invention ]

Disclosed herein is a method comprising: transmitting M bombardment beams (i), i=1, … …, M) to target points (i), i=1, … …, M) on the target, respectively, thereby obtaining radiation beams (i), i=1, … …, M) emitted from the target points (i), i=1, … …, M, respectively, and propagating toward the object, wherein M is an integer greater than 1; and for each value of i, obtaining a 2D (two-dimensional) image (i) of the object using radiation of the radiation beam (i) that has passed through the object, wherein the target is stationary relative to the object.

In one aspect, the method further comprises reconstructing a 3D (three-dimensional) image of the object from the 2D image (i), i=1, … …, M.

In one aspect, the obtaining a 2D image (i) of the object comprises: capturing Ni partial images of the object one by one using the radiation of the radiation beam (i) that has passed through the object, wherein Ni is an integer greater than 1; and stitching the Ni partial images of the object, thereby obtaining the 2D image (i) of the object.

In one aspect, all of the Ni, i=1, &.. M is the same.

In one aspect, each of the M bombardment beams comprises an electron beam.

In one aspect, the target comprises copper or tungsten.

In one aspect, the bombarding beams (i), i=1, … …, M are sent one by one.

In one aspect, the image sensor obtains all of said 2D images (i), i=1, … …, M.

In one aspect, the transmitting the M bombardment beams is performed using a bombardment beam generator comprising a plurality of electron guns, each of the electron guns transmitting at least one of the M bombardment beams.

In one aspect, the bombardment beam generator is physically fixed to the target.

Disclosed herein is an imaging system comprising: a bombardment beam generator; a target; and an image sensor system comprising at least one image sensor, wherein the bombardment beam generator is configured to send M bombardment beams (i), i=1, … …, M) to a target point (i), i=1, … …, M, respectively, on the object resulting in a radiation beam (i), i=1, … …, M) emitted from the target point (i), i=1, … …, M, respectively, and propagating towards the object, wherein M is an integer greater than 1, wherein the image sensor system is configured to obtain a 2D (two-dimensional) image (i) of the object using radiation of the radiation beam (i) that has passed through the object for each value of i, and wherein the object is stationary relative to the object.

In an aspect, the image sensor system is further configured to reconstruct a 3D (three-dimensional) image of the object from the 2D image (i), i=1, … …, M.

In an aspect, the image sensor system is further configured to obtain the 2D image (i) of the object by: capturing Ni partial images of the object one by one using the radiation of the radiation beam (i) that has passed through the object, wherein Ni is an integer greater than 1; and stitching the Ni partial images of the object, thereby obtaining the 2D image (i) of the object.

In one aspect, all of the Ni, i=1, &.. M is the same.

In one aspect, each of the M bombardment beams comprises an electron beam.

In one aspect, the target comprises copper or tungsten.

In one aspect, the bombarding beams (i), i=1, … …, M are sent one by one.

In one aspect, the image sensor of the image sensor system obtains all of the 2D images (i), i=1, … …, M.

In one aspect, the bombardment beam generator comprises a plurality of electron guns, each of the electron guns transmitting at least one of the M bombardment beams.

[ Description of the drawings ]

Fig. 1 schematically shows a radiation detector according to an embodiment.

Fig. 2 schematically shows a simplified cross-sectional view of a radiation detector according to an embodiment.

Fig. 3 schematically shows a detailed cross-sectional view of a radiation detector according to an embodiment.

Fig. 4 schematically shows a detailed cross-sectional view of a radiation detector according to an alternative embodiment.

Fig. 5 schematically illustrates a top view of a package including a radiation detector and a Printed Circuit Board (PCB) according to an embodiment.

Fig. 6 schematically illustrates a cross-sectional view of the packaged image sensor of fig. 5 including mounting to a system PCB (printed circuit board) according to an embodiment.

Fig. 7A to 7C schematically show perspective views of an imaging system in operation according to an embodiment.

Fig. 8 shows a flow chart summarizing the operation of the imaging system.

[ Detailed description ] of the invention

Radiation detector

As an example, fig. 1 schematically shows a radiation detector 100. The radiation detector 100 may include an array of pixels 150 (also referred to as sensing elements 150). The array may be a rectangular array (as shown in fig. 1), a cellular array, a hexagonal array, or any other suitable array. The array of pixels 150 in the example of fig. 1 has 4 rows and 7 columns; in general, however, an array of pixels 150 may have any number of rows and any number of columns.

Each pixel 150 may be configured to detect radiation incident thereon from a radiation source (not shown) and may be configured to measure characteristics of the radiation (e.g., energy, wavelength, and frequency of the particles). The radiation may include particles, such as photons and subatomic particles. Each pixel 150 may be configured to count the number of radiation particles over a period of time for which energy incident thereon falls in a plurality of energy intervals. All pixels 150 may be configured to count the number of radiation particles incident thereon over a plurality of energy intervals over the same period of time. When the incident radiation particles have similar energies, the pixel 150 may simply be configured to count the number of radiation particles incident thereon over a period of time without measuring the energies of the individual radiation particles.

Each pixel 150 may have its own analog-to-digital converter (ADC) configured to digitize an analog signal representing the energy of the incident radiation particle into a digital signal, or to digitize an analog signal representing the total energy of a plurality of incident radiation particles into a digital signal. The pixels 150 may be configured to operate in parallel. For example, while one pixel 150 is measuring an incident radiation particle, another pixel 150 may be waiting for the radiation particle to arrive. The pixels 150 may not necessarily be individually addressable.

The radiation detector 100 described herein may be applied to, for example, an X-ray telescope, X-ray mammography, industrial X-ray defect detection, X-ray microscope or micro-radiography, X-ray casting inspection, X-ray nondestructive testing, X-ray weld inspection, X-ray digital subtraction angiography, and the like. It may also be suitable to use the radiation detector 100 instead of a photographic plate, photographic film, photo-excited fluorescent plate (PSP plate), X-ray image intensifier, scintillator or other semiconductor X-ray detector.

Fig. 2 schematically illustrates a simplified cross-sectional view of the radiation detector 100 of fig. 1 along line 2-2, in accordance with an embodiment. In particular, radiation detector 100 may include a radiation absorbing layer 110 and an electronics layer 120 (which may include one or more ASICs or application specific integrated circuits) for processing or analyzing electrical signals generated in radiation absorbing layer 110 by incident radiation. The radiation detector 100 may or may not include a scintillator (not shown). The radiation absorbing layer 110 may comprise a semiconductor material, such as silicon, germanium, gaAs, cdTe, cdZnTe, or a combination thereof. The semiconductor material may have a high mass attenuation coefficient for the radiation of interest.

Fig. 3 schematically shows a detailed cross-sectional view of the radiation detector 100 of fig. 1 along line 2-2 as an example. In particular, the radiation absorbing layer 110 can include one or more diodes (e.g., p-i-n or p-n) formed from one or more discrete regions 114 of the first doped region 111, the second doped region 113. The second doped region 113 may be separated from the first doped region 111 by an optional intrinsic region 112. The discrete regions 114 may be separated from each other by the first doped region 111 or the intrinsic region 112. The first doped region 111 and the second doped region 113 may have opposite types of doping (e.g., region 111 is p-type, region 113 is n-type, or region 111 is n-type, region 113 is p-type). In the example of fig. 3, each discrete region 114 of the second doped region 113 forms a diode with the first doped region 111 and the optional intrinsic region 112. That is, in the example of fig. 3, the radiation absorbing layer 110 has a plurality of diodes (more specifically, 7 diodes correspond to 7 pixels 150 of a row in the array of fig. 1, of which only two 150 are labeled in fig. 3 for simplicity). The plurality of diodes may have electrical contacts 119A as common (common) electrodes. The first doped region 111 may also have a plurality of discrete portions.

The electronics layer 120 may include an electronic system 121 adapted to process or interpret signals generated by radiation incident on the radiation absorbing layer 110. The electronic system 121 may include analog circuits such as a filter network, amplifiers, integrators, and comparators, or digital circuits such as a microprocessor and memory. The electronics 121 may include one or more ADCs (analog to digital converters). The electronics 121 may include components that are common to the pixels 150 or components that are dedicated to a single pixel 150. For example, the electronic system 121 may include an amplifier dedicated to each pixel 150 and a microprocessor shared among all pixels 150. The electronic system 121 may be electrically connected to the pixel 150 through the via 131. The space between the vias may be filled with a filler material 130, which may increase the mechanical stability of the connection of the electronic device layer 120 with the radiation absorbing layer 110. Other bonding techniques may connect the electronics 121 to the pixel 150 without the use of a via 131.

When radiation from a radiation source (not shown) impinges on the radiation absorbing layer 110, which includes a diode, the radiation particles may be absorbed and generate one or more charge carriers (e.g., electrons, holes) through a variety of mechanisms. Charge carriers may drift under an electric field to the electrode of one of the diodes. The electric field may be an external electric field. The electrical contact 119B can include a plurality of discrete portions, each of which is in electrical contact with the discrete region 114. The term "electrical contact" may be used interchangeably with the word "electrode". In one embodiment, the charge carriers may drift in multiple directions and such that charge carriers generated by a single radiating particle are not substantially shared by two different discrete regions 114 (herein, "substantially not shared" means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of the charge carriers flow to one different discrete region 114 as compared to the rest of the charge carriers). Charge carriers generated by radiation particles incident on the surroundings of the footprint (footprint) of one of the discrete regions 114 are not substantially shared with another one of the discrete regions 114. The pixels 150 associated with the discrete region 114 may be the region surrounding the discrete region 114 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 the radiation particles incident therein flow to 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 out of the pixel 150.

Fig. 4 schematically illustrates a detailed cross-sectional view of the radiation detector 100 of fig. 1 along line 2-2, in accordance with an alternative embodiment. More specifically, the radiation absorbing layer 110 may include a resistor of semiconductor material, such as silicon, germanium, gaAs, cdTe, cdZnTe, or a combination thereof, but not include a diode. The semiconductor material may have a high mass attenuation coefficient for the radiation of interest. In one embodiment, the electronic device layer 120 of fig. 4 is similar in structure and function to the electronic device layer 120 of fig. 3.

When radiation strikes radiation absorbing layer 110, which includes a resistor rather than a diode, it can be absorbed and one or more charge carriers are generated by a variety of mechanisms. The radiating particles may generate 10 to 100,000 charge carriers. Charge carriers may drift under an electric field to electrical contacts 119A and 119B. The electric field may be an external electric field. The electrical contact 119B may include a plurality of discrete portions. In one embodiment, the charge carriers may drift in multiple directions and such that charge carriers generated by a single radiation particle are not substantially shared by two different discrete portions of the electrical contact 119B (here, "substantially not shared" means that less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of the charge carriers flow to a different discrete portion as compared to the rest of the charge carriers). Charge carriers generated by radiation particles incident on the surroundings of the footprint of one of the discrete portions of electrical contact 119B are not substantially shared with the other of the discrete portions of electrical contact 119B. The pixel 150 associated with one 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 the radiation particles incident therein flow to 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 the charge carriers flow out of the pixel associated with the one discrete portion of electrical contact 119B.

Radiation detector package

Fig. 5 schematically shows a top view of a package 500 comprising a radiation detector 100 and a Printed Circuit Board (PCB) 510. The term "PCB" as used herein is not limited to a particular material. For example, the PCB may include a semiconductor. The radiation detector 100 may be mounted to the PCB 510. For clarity, wiring between radiation detector 100 and PCB 510 is not shown. PCB 510 may have one or more radiation detectors 100. The PCB 510 may have an area 512 not covered by the radiation detector 100 (e.g., for accommodating bond wires 514). The radiation detector 100 may have an active area 190 where the pixels 150 (fig. 1) are located. The radiation detector 100 may have a peripheral region 195 located near the edge of the radiation detector 100. The peripheral region 195 is devoid of pixels 150 and the radiation detector 100 does not detect radiation particles incident on the peripheral region 195.

Image sensor

Fig. 6 schematically shows a cross-sectional view of an image sensor 600 according to an embodiment. The image sensor 600 may include one or more of the packages 500 of fig. 5 mounted to a system PCB 650. As an example, fig. 6 shows two packages 500. The electrical connection between the PCB 510 and the system PCB 650 may be made by bond wires 514. To accommodate bond wires 514 on PCB 510, PCB 510 may have areas 512 that are not covered by radiation detector 100. To accommodate bond wires 514 on system PCB 650, packages 500 may have a gap between them. The gap may be about 1mm or more. Radiation particles incident on the peripheral region 195, region 512 or gap cannot be detected by the package 500 on the system PCB 650. The dead zone of a radiation detector (e.g., radiation detector 100) is the area of the radiation receiving surface of the radiation detector on which radiation particles incident thereon cannot be detected by the radiation detector. The dead zone of a package (e.g., package 500) is the area of the radiation receiving surface of the package on which radiation particles incident thereon cannot be detected by one or more radiation detectors in the package. In this example shown in fig. 5 and 6, the dead zone of package 500 includes peripheral zone 195 and zone 512. Dead zones (e.g., 688) of image sensors (e.g., image sensor 600) having a set of packages (e.g., packages 500 mounted on the same PCB and arranged in the same layer or different layers) include a combination of dead zones of packages and gaps between packages in the set.

In one embodiment, the radiation detector 100 (FIG. 1) operated by itself may be considered an image sensor. In one embodiment, the package 500 (fig. 5) operated by itself may be considered an image sensor.

The image sensor 600 including the radiation detector 100 may have dead zones 688 that are unable to detect incident radiation. However, the image sensor 600 may capture a plurality of partial images of an object or scene (not shown) and then may stitch the captured partial images to form an image of the entire object or scene.

Imaging system

Fig. 7A-7C schematically illustrate perspective views of an imaging system 700 in operation according to an embodiment. In an embodiment, imaging system 700 may include a bombardment beam generator 710, a target 725, and an image sensor system 100a+100b+100c. In an embodiment, bombardment beam generator 710 may be configured to generate a bombardment beam (e.g., an electron beam) toward target 725.

In an embodiment, target 725 may have a ring shape as shown. In an embodiment, there may be 3 target points 720a, 720b, and 720c on the surface of target 725. Each of target points 720a, 720b, and 720c may be an area or field on the surface of target 725 that is to receive bombarded particles (e.g., electrons) from bombarded beam generator 710. The 3 black circles representing the 3 target points 720a, 720b, and 720c are merely approximate indications of the locations of the target points 720a, 720b, and 720c on the target 725, and do not necessarily indicate the size, shape, or orientation of the target points 720a, 720b, and 720c.

In an embodiment, target 725 may be made of copper or tungsten. As shown, target 725 may be one-piece. Or target 725 may comprise a plurality of separate components (not shown).

In an embodiment, image sensor system 100a+100b+100c may include 3 radiation detectors 100a, 100b, and 100c, which may be similar to radiation detector 100 of fig. 1. The 3 parallelograms representing the 3 radiation detectors 100a, 100b, 100c are merely approximate indications of the position and orientation of the radiation detectors 100a, 100b, 100c, and do not necessarily indicate the size and shape of the radiation detectors 100a, 100b, 100 c. In an embodiment, the radiation detectors 100a, 100b, and 100c may be physically secured to the circular track 105, as shown.

In an embodiment, the object 730 may be positioned between the target points 720a, 720b, and 720c and the image sensor system 100a+100b+100c, as shown, for imaging by the imaging system 700. Object 730 may be a patient whose body part needs to be imaged for medical diagnostic purposes. In an embodiment, the target points 720a, 720b, and 720c may be such that when a bombardment beam (e.g., an electron beam) from the bombardment beam generator 710 bombards the target 725 at the target points 720a, 720b, and 720c, a radiation beam (e.g., X-rays) will be emitted from the target points 720a, 720b, and 720c and propagate toward the object 730.

In an embodiment, target 725 may be stationary relative to object 730 during the operation of imaging system 700 to image object 730. In an embodiment, the rail 105 may be stationary relative to the object 730 during operation of the imaging system 700 to image the object 730.

First 2D image taking

In an embodiment, referring to fig. 7A, the first 2D (two-dimensional) image photographing may be performed as follows. The bombardment beam generator 710 may generate a bombardment beam 712a towards a target point 720a on the target 725, resulting in emission of a radiation beam 722a from the target point 720a towards the object 730. Using radiation of the radiation beam 722a that has passed through the object 730, the radiation detector 100a may take a first 2D image of the object 730.

Second 2D image taking

In an embodiment, referring to fig. 7B, the second 2D image photographing may be performed as follows. The bombardment beam generator 710 may generate a bombardment beam 712b directed toward a target point 720b on the target 725, resulting in emission of a radiation beam 722b from the target point 720b toward the object 730. Using the radiation of the radiation beam 722b that has passed through the object 730, the radiation detector 100b may take a second 2D image of the object 730.

Third 2D image shooting

In an embodiment, referring to fig. 7C, the third 2D image photographing may be performed as follows. The bombardment beam generator 710 may generate a bombardment beam 712c towards a target point 720c on the target 725, resulting in emission of a radiation beam 722c from the target point 720c towards the object 730. Using radiation of the radiation beam 722c that has passed through the object 730, the radiation detector 100c may take a third 2D image of the object 730.

Flow chart for generalization

Fig. 8 shows a flowchart 800 outlining the operation of the imaging system 700 described above. Specifically, in step 810, M bombarding beams (i), i=1, … …, M) are respectively transmitted to target points (i), i=1, … …, M on the target, thereby obtaining radiation beams (i), i=1, … …, M) respectively emitted from the target points (i), i=1, … …, M and propagating toward the object, wherein M is an integer greater than 1. For example, referring to fig. 7A-8, three bombardment beams 712a, 712b and 712c (where m=3) are sent towards target points 720a, 720b and 720c, respectively, on target 725, resulting in radiation beams 722a, 722b and 722c emitted from target points 720a, 720b and 720c, respectively, and propagating towards object 730.

In step 820, for each value of i, a 2D image (i) of the object is obtained using radiation of the radiation beam (i) that has passed through the object. For example, for i=1, the radiation of the radiation beam 722a (fig. 7A) that has passed through the object 730 is used to obtain a first 2D image of the object 730. For i=2, a second 2D image of the object 730 is obtained using radiation of the radiation beam 722B (fig. 7B) that has passed through the object 730. For i=3, a third 2D image of the object 730 is obtained using radiation of the radiation beam 722C (fig. 7C) that has passed through the object 730.

Also in step 820, the target is stationary relative to the object. For example, target 725 is stationary relative to object 730.

3D image reconstruction

In an embodiment, referring to step 820 in flowchart 800 of fig. 8, a 3D (three-dimensional) image of an object may be reconstructed from 2D images (i), i=1, … …, M. For example, referring to fig. 7A-7C, a 3D image of the object 730 may be reconstructed from a first 2D image, a second 2D image, and a third 2D image of the object 730 (as described above). In an embodiment, the radiation detectors 100a, 100b and 100c may be configured to communicate with each other such that at least one of them has access to all of the first, second and third 2D images and a 3D image may be reconstructed from the first, second and third 2D images.

A single radiation detector obtains all 2D images

In an embodiment, referring to step 820 of flowchart 800 of fig. 6, a single image sensor may be used to obtain all 2D images (i), i=1, … …, M. For example, referring to fig. 7A-7C, instead of three radiation detectors 100a, 100b and 100C as described above for obtaining first, second and third 2D images, respectively, the radiation detector 100a (which may itself be considered an image sensor) may be moved along the track 105 and obtain all of the first, second and third 2D images. This is possible if the first 2D image capturing, the second 2D image capturing, and the third 2D image capturing are performed one by one. This means that bombardment beam generator 710 sends bombardment beams 712a, 712b and 712c one by one.

In particular, when the bombardment beam generator 710 sends the bombardment beam 712a (fig. 7A), the radiation detector 100a may be at its position as shown in fig. 7A and a first 2D image may be taken. Later, in an embodiment, when the bombardment beam generator 710 sends the bombardment beam 712B (fig. 7B), the radiation detector 100a may be at the location of the radiation detector 100B as shown in fig. 7B and a second 2D image may be taken. Later, in an embodiment, when the bombardment beam generator 710 sends the bombardment beam 712C (fig. 7C), the radiation detector 100a may be at the location of the radiation detector 100C as shown in fig. 7C and a third 2D image may be taken. As a result, the radiation detector 100a obtains all of the first, second and third 2D images.

Multiple partial images of each 2D image

In an embodiment, referring to step 820 in flowchart 800 of fig. 8, the obtaining a 2D image (i) of the object may include (a) capturing Ni partial images of the object one by one using radiation of a radiation beam (i) that has passed through the object, where Ni is an integer greater than 1; and (B) stitching Ni partial images of the object, thereby obtaining a 2D image (i) of the object. For example, referring to fig. 7A, for a first 2D image capture (i.e., for i=1), instead of capturing the first 2D image in one capture as described above, the radiation detector 100a may use radiation of the radiation beam 722a that has passed through the object 730 to capture N1 partial images of the object 730.

Specifically, assuming n1=3, while the radiation beam 722a is on, the radiation detector 100a may take a first partial image of the object 730 while the radiation detector 100a is located at the first position as shown in fig. 7A. Next, in an embodiment, while the radiation beam 722a is still on, the radiation detector 100a may be moved along the track 105 to a second position (not shown) and then a second partial image of the object 730 is captured while the radiation detector 100a is located at the second position. Next, in an embodiment, while the radiation beam 722a is still on, the radiation detector 100a may be further moved along the track 105 to a third position (not shown) and then a third partial image of the object 730 is captured while the radiation detector 100a is located at the third position. Next, in an embodiment, the first, second and third partial images may be stitched by the radiation detector 100a, resulting in a first 2D image of the object 730.

In an embodiment, the second 2D image and the third 2D image may be obtained by the radiation detectors 100b and 100c, respectively, in a similar manner. Or the radiation detector 100a may move alone along the track 105 and take all 9 partial images of the object 730 (assuming n1=n2=n3=3), thereby obtaining all the first, second and third 2D images of the object 730.

In an embodiment, all of the Ni, i=1, &.. M may be the same. For example, in the above embodiment, n1=n2=n3=3. In other words, in order to obtain each of the first, second, and third 2D images, 3 partial images of the object 730 may be photographed one by one and then stitched to obtain the 2D image as described above. Typically, ni, i=1. For example, n1=3, n2=4, and n3=2 may be used.

More information about the bombarding beam generator

In an embodiment, referring to fig. 7A-7C, the bombardment beam generator 710 may be stationary relative to the object 730. In an embodiment, bombardment beam generator 710 may be physically fixed to target 725.

In an embodiment, the bombardment beam generator 710 may include a plurality of electron guns (not shown) each of which may transmit at least one of the bombardment beams 712a, 712b and 712c. For example, the bombardment beam generator 710 may include a first electron gun and a second electron gun (not shown), where the first electron gun transmits the bombardment beam 712a and the second electron gun transmits the bombardment beams 712b and 712c. In an embodiment, the second electron gun may send bombardment beams 712b and 712c one by one.

While 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 purposes of illustration and not limitation, with the true scope and spirit being indicated by the following claims.

Claims

1. A method, comprising:

Transmitting M bombardment beams (i), i=1, … …, M) to target points (i), i=1, … …, M) on the target, respectively, thereby obtaining radiation beams (i), i=1, … …, M) emitted from the target points (i), i=1, … …, M, respectively, and propagating toward the object, wherein M is an integer greater than 1; and

For each value of i, obtaining a 2D (two-dimensional) image (i) of the object using radiation of the radiation beam (i) that has passed through the object,

Wherein the target is stationary relative to the object.

2. The method of claim 1, further comprising reconstructing a 3D (three-dimensional) image of the object from the 2D image (i), i = 1, … …, M.

3. The method of claim 1, wherein the obtaining the 2D image (i) of the object comprises:

Capturing Ni partial images of the object one by one using radiation of the radiation beam (i) that has passed through the object, wherein Ni is an integer greater than 1; and

Stitching the Ni partial images of the object, thereby obtaining the 2D image (i) of the object.

4. A method according to claim 3, wherein all Ni, i = 1, … …, M are the same.

5. The method of claim 1, wherein each of the M bombardment beams comprises an electron beam.

6. The method of claim 1, wherein the target comprises copper or tungsten.

7. The method of claim 1, wherein the bombardment beams (i), i = 1, … …, M are sent one by one.

8. The method of claim 1, wherein an image sensor obtains all of the 2D images (i), i = 1, … …, M.

9. The method of claim 1, wherein said transmitting said M bombardment beams is performed using a bombardment beam generator comprising a plurality of electron guns, each of said electron guns transmitting at least one of said M bombardment beams.

10. The method of claim 9, wherein the bombardment beam generator is physically fixed to the target.

11. An imaging system, comprising:

A bombardment beam generator;

A target; and

An image sensor system comprising at least one image sensor,

Wherein the bombardment beam generator is configured to send M bombardment beams (i), i=1, … …, M) to target points (i), i=1, … …, M) on the target, respectively, resulting in radiation beams (i), i=1, … …, M) emitted from the target points (i) i=1, … …, M, respectively, and propagating towards the object, wherein M is an integer greater than 1,

Wherein the image sensor system is configured to obtain a 2D (two-dimensional) image (i) of the object using radiation of the radiation beam (i) that has passed through the object, for each value of i, and

Wherein the target is stationary relative to the object.

12. The imaging system of claim 11, wherein the image sensor system is further configured to reconstruct a 3D (three-dimensional) image of the object from the 2D image (i), i = 1, … …, M.

13. The imaging system of claim 11, wherein the image sensor system is further configured to obtain the 2D image (i) of the object by:

14. The imaging system of claim 13, wherein, all of the Ni is contained in the alloy, i=1, &.. M is the same.

15. The imaging system of claim 11, wherein each of the M bombardment beams comprises an electron beam.

16. The imaging system of claim 11, wherein the target comprises copper or tungsten.

17. The imaging system of claim 11, wherein the bombardment beams (i), i = 1, … …, M are sent one by one.

18. The imaging system of claim 11, wherein an image sensor of the image sensor system obtains all of the 2D images (i), i = 1, … …, M.

19. The imaging system of claim 11, wherein the bombardment beam generator comprises a plurality of electron guns, each of the electron guns transmitting at least one of the M bombardment beams.

20. The imaging system of claim 19, wherein the bombardment beam generator is physically fixed to the target.