A radiation detector is a device that measures a property of a radiation. Examples of the property may include a spatial distribution of the intensity, phase, and polarization of the radiation. The radiation may be one that has interacted with an object. For example, the radiation measured by the radiation detector may be a radiation that has penetrated the object. The radiation may be an electromagnetic radiation such as infrared light, visible light, ultraviolet light, X-ray, or γ-ray. The radiation may be of other types such as α-rays and βrays. An imaging system may include an image sensor having multiple radiation detectors.
Disclosed herein is a method, comprising shining a scene with radiation pulses (i), i=1, . . . , M, one pulse at a time, wherein M is an integer greater than 1; for i=1, . . . , M, during the radiation pulse (i) and utilizing radiation of the radiation pulse (i), capturing, one by one, partial images (i,j), j=1, . . . , Ni of the scene with a same image sensor, wherein Ni, i=1, . . . , M are all integers greater than 1; for i=1, . . . , M, generating an enhanced partial image (i) from the partial images (i,j), j=1, . . . , Ni by applying one or more super resolution algorithms to the partial images (i,j), j=1, . . . , Ni; and stitching the enhanced partial images (i), i=1, . . . , M resulting in a stitched image of the scene.
In an aspect, all Ni, i=1, . . . , M are the same.
In an aspect, all Ni, i=1, . . . , M are greater than 100.
In an aspect, for i=1, . . . , M, during the radiation pulse (i), the image sensor moves continuously with respect to the scene.
In an aspect, the image sensor moves continuously with respect to the scene during a time period in which the image sensor captures all the partial images (i,j), i=1, . . . , M, and j=1, . . . , Ni.
In an aspect, said moving of the image sensor with respect to the scene during the time period is at a constant speed.
In an aspect, the method further comprises arranging a mask such that for i=1, . . . , M, during the radiation pulse (i), (A) radiation of the radiation pulse (i) which is aimed at the scene but not aimed at active areas of the image sensor is prevented by the mask from reaching the scene, and (B) radiation of the radiation pulse (i) which is aimed at the scene and also aimed at the active areas of the image sensor is allowed by the mask to pass through the mask so as to reach the scene.
In an aspect, during each of the radiation pulses (i), i=1, . . . , M, the image sensor moves a distance of less than a width of a sensing element of the image sensor measured in a direction of said moving of the image sensor.
In an aspect, during each of the radiation pulses (i), i=1, . . . , M, the image sensor moves a distance of less than one half of said width.
In an aspect, the image sensor comprises multiple radiation detectors.
Disclosed herein is an imaging system, comprising a radiation source configured to shine a scene with radiation pulses (i), i=1, . . . , M, one pulse at a time, wherein M is an integer greater than 1; and an image sensor configured to, for i=1, . . . , M, during the radiation pulse (i) and utilizing radiation of the radiation pulse (i), capture one by one, partial images (i,j), j=1, . . . , Ni of the scene, wherein Ni, i=1, . . . , M are all integers greater than 1, wherein the image sensor is configured to, for i=1, . . . , M, generate an enhanced partial image (i) from the partial images (i,j), j=1, . . . , Ni by applying one or more super resolution algorithms to the partial images (i,j), j=1, . . . , Ni, and wherein the image sensor is configured to stitch the enhanced partial images (i), i=1, . . . , M resulting in a stitched image of the scene.
In an aspect, all Ni, i=1, . . . , M are the same.
In an aspect, all Ni, i=1, . . . , M are greater than 100.
In an aspect, for i=1, . . . , M, during the radiation pulse (i), the image sensor is configured to move continuously with respect to the scene.
In an aspect, the image sensor is configured to move continuously with respect to the scene during a time period in which the image sensor captures all the partial images (i,j), i=1, . . . , M, and j=1, . . . , Ni.
In an aspect, said moving of the image sensor with respect to the scene during the time period is at a constant speed.
In an aspect, the imaging system further comprises a mask arranged such that for i=1, . . . , M, during the radiation pulse (i), (A) radiation of the radiation pulse (i) which is aimed at the scene but not aimed at active areas of the image sensor is prevented by the mask from reaching the scene, and (B) radiation of the radiation pulse (i) which is aimed at the scene and also aimed at the active areas of the image sensor is allowed by the mask to pass through the mask so as to reach the scene.
In an aspect, during each of the radiation pulses (i), i=1, . . . , M, the image sensor is configured to move a distance of less than a width of a sensing element of the image sensor measured in a direction of said moving of the image sensor.
In an aspect, during each of the radiation pulses (i), i=1, . . . , M, the image sensor is configured to move a distance of less than one half of said width.
In an aspect, the image sensor comprises multiple radiation detectors.
Each pixel 150 may be configured to detect radiation from a radiation source (not shown) incident thereon and may be configured to measure a characteristic (e.g., the energy of the particles, the wavelength, and the frequency) of the radiation. A radiation may include particles such as photons and subatomic particles. Each pixel 150 may be configured to count numbers of particles of radiation incident thereon whose energy falls in a plurality of bins of energy, within a period of time. All the pixels 150 may be configured to count the numbers of particles of radiation incident thereon within a plurality of bins of energy within the same period of time. When the incident particles of radiation have similar energy, the pixels 150 may be simply configured to count numbers of particles of radiation incident thereon within a period of time, without measuring the energy of the individual particles of radiation.
Each pixel 150 may have its own analog-to-digital converter (ADC) configured to digitize an analog signal representing the energy of an incident particle of radiation into a digital signal, or to digitize an analog signal representing the total energy of a plurality of incident particles of radiation into a digital signal. The pixels 150 may be configured to operate in parallel. For example, when one pixel 150 measures an incident particle of radiation, another pixel 150 may be waiting for a particle of radiation to arrive. The pixels 150 may not have to be individually addressable.
The radiation detector 100 described here may have applications such as in an X-ray telescope, X-ray mammography, industrial X-ray defect detection, X-ray microscopy or microradiography, X-ray casting inspection, X-ray non-destructive testing, X-ray weld inspection, X-ray digital subtraction angiography, etc. It may be suitable to use this radiation detector 100 in place of a photographic plate, a photographic film, a PSP plate, an X-ray image intensifier, a scintillator, or another semiconductor X-ray detector.
The electronics layer 120 may include an electronic system 121 suitable for processing or interpreting signals generated by the radiation incident on the radiation absorption layer 110. The electronic system 121 may include an analog circuitry such as a filter network, amplifiers, integrators, and comparators, or a digital circuitry such as a microprocessor, and memory. The electronic system 121 may include one or more ADCs (analog to digital converters). The electronic system 121 may include components shared by the pixels 150 or components 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 the pixels 150. The electronic system 121 may be electrically connected to the pixels 150 by vias 131. Space among the vias may be filled with a filler material 130, which may increase the mechanical stability of the connection of the electronics layer 120 to the radiation absorption layer 110. Other bonding techniques are possible to connect the electronic system 121 to the pixels 150 without using the vias 131.
When radiation from the radiation source (not shown) hits the radiation absorption layer 110 including diodes, particles of the radiation may be absorbed and generate one or more charge carriers (e.g., electrons, holes) by a number of mechanisms. The charge carriers may drift to the electrodes of one of the diodes under an electric field. The electric field may be an external electric field. The electrical contact 1198 may include discrete portions each of which is in electrical contact with the discrete regions 114. The term “electrical contact” may be used interchangeably with the word “electrode.” In an embodiment, the charge carriers may drift in directions such that the charge carriers generated by a single particle of the radiation are not substantially shared by two different discrete regions 114 (“not substantially shared” here means less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a different one of the discrete regions 114 than the rest of the charge carriers). Charge carriers generated by a particle of the radiation incident around the footprint of one of these discrete regions 114 are not substantially shared with another of these discrete regions 114. A pixel 150 associated with a discrete region 114 may be an area around the discrete region 114 in which substantially all (more than 98%, more than 99.5%, more than 99.9%, or more than 99.99% of) charge carriers generated by a particle of the radiation incident therein flow to the discrete region 114. Namely, less than 2%, less than 1%, less than 0.1%, or less than 0.01% of these charge carriers flow beyond the pixel 150.
When the radiation hits the radiation absorption layer 110 including the resistor but not diodes, it may be absorbed and generate one or more charge carriers by a number of mechanisms. A particle of the radiation may generate 10 to 100,000 charge carriers. The charge carriers may drift to the electrical contacts 119A and 119B under an electric field. The electric field may be an external electric field. The electrical contact 119B may include discrete portions. In an embodiment, the charge carriers may drift in directions such that the charge carriers generated by a single particle of the radiation are not substantially shared by two different discrete portions of the electrical contact 119B (“not substantially shared” here means less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow to a different one of the discrete portions than the rest of the charge carriers). Charge carriers generated by a particle of the radiation incident around the footprint of one of these discrete portions of the electrical contact 119B are not substantially shared with another of these discrete portions of the electrical contact 119B. A pixel 150 associated with a discrete portion of the electrical contact 119B may be an area around the discrete portion in which substantially all (more than 98%, more than 99.5%, more than 99.9% or more than 99.99% of) charge carriers generated by a particle of the radiation incident therein flow to the discrete portion of the electrical contact 119B. Namely, less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow beyond the pixel associated with the one discrete portion of the electrical contact 119B.
The image sensor 490 including the radiation detectors 100 may have the dead zone 488 incapable of detecting incident radiation. However, the image sensor 490 may capture partial images of all points of an object or scene (not shown), and then these captured partial images may be stitched to form an image of the entire object or scene.
In an embodiment, during the imaging session, the image sensor 490 may move from left to right while an object (or scene) 510 remains stationary as the image sensor 490 scans the object 510. For example, the object 510 may be a cardboard box containing a sword 512.
In an embodiment, during the imaging session, a radiation source 720 (
In an embodiment, the imaging session may start with the image sensor 490 moving to the right to a first imaging position as shown in
Next, in an embodiment, the image sensor 490 may move further to the right by a short distance (e.g., less than the size of a pixel 150 of the image sensor 490) to a second imaging position (not shown). At the second imaging position, using the radiation from the radiation source 720, the image sensor 490 may capture a partial image 520A2 (
Next, in an embodiment, the image sensor 490 may move further to the right by a short distance (e.g., less than the size of a pixel 150 of the image sensor 490) to a third imaging position (not shown). At the third imaging position, using the radiation from the radiation source 720, the image sensor 490 may capture a partial image 520A3 (
Next, in an embodiment, the image sensor 490 may move further to the right by a long distance (e.g., about the width 190w (
Next, in an embodiment, the image sensor 490 may move further to the right by a short distance (e.g., less than the size of a pixel 150 of the image sensor 490) to a fifth imaging position (not shown). At the fifth imaging position, using the radiation from the radiation source 720, the image sensor 490 may capture a partial image 520B2 (
Next, in an embodiment, the image sensor 490 may move further to the right by a short distance (e.g., less than the size of a pixel 150 of the image sensor 490) to a sixth imaging position (not shown). At the sixth imaging position, using the radiation from the radiation source 720, the image sensor 490 may capture a partial image 520B3 (
Next, in an embodiment, the image sensor 490 may move further to the right by a long distance (e.g., about the width 190w (
Next, in an embodiment, the image sensor 490 may move further to the right by a short distance (e.g., less than the size of a pixel 150 of the image sensor 490) to an eighth imaging position (not shown). At the eighth imaging position, using the radiation from the radiation source 720, the image sensor 490 may capture a partial image 520C2 (
Next, in an embodiment, the image sensor 490 may move further to the right by a short distance (e.g., less than the size of a pixel 150 of the image sensor 490) to a ninth imaging position (not shown). At the ninth imaging position, using the radiation from the radiation source 720, the image sensor 490 may capture a partial image 520C3 (
In an embodiment, throughout the imaging session during which the 9 partial images 520A1, 520A2, 520A3, 520B1, 520B2, 520B3, 520C1, 520C2, and 520C3 are captured, the radiation source may shine the image sensor 490 and the object 510 with radiation all the time. In an alternative embodiment, during the imaging session, the radiation source 720 may shine the image sensor 490 and the object 510 with radiation in pulses. Specifically, during each pulse, the radiation source 720 shines the image sensor 490 and the object 510 with radiation. However, between the pulses, the radiation source 720 does not shine the image sensor 490 and the object 510 with radiation. In an embodiment, this may be implemented by keeping the radiation source 720 off between the pulses and on during the pulses.
In an embodiment, a first radiation pulse may start before the image sensor 490 captures the partial image 520A1 and end after the image sensor 490 captures the partial image 520A3. In other words, the image sensor 490 captures the partial images 520A1, 520A2, and 520A3 during the first radiation pulse.
In an embodiment, a second radiation pulse may start before the image sensor 490 captures the partial image 520B1 and end after the image sensor 490 captures the partial image 520B3. In other words, the image sensor 490 captures the partial images 520B1, 520B2, and 520B3 during the second radiation pulse.
In an embodiment, a third radiation pulse may start before the image sensor 490 captures the partial image 520C1 and end after the image sensor 490 captures the partial image 520C3. In other words, the image sensor 490 captures the partial images 520C1, 520C2, and 520C3 during the third radiation pulse.
In an embodiment, a first enhanced partial image (not shown) of the object 510 may be generated from the partial images 520A1, 520A2, and 520A3. In an embodiment, one or more super resolution algorithms may be applied to the partial images 520A1, 520A2, and 520A3 so as to generate the first enhanced partial image. In an embodiment, the one or more super resolution algorithms may be applied to the partial images 520A1, 520A2, and 520A3 by the image sensor 490.
In an embodiment, similarly, a second enhanced partial image (not shown) of the object 510 may be generated from the partial images 520B1, 520B2, and 520B3. In an embodiment, one or more super resolution algorithms may be applied to the partial images 520B1, 520B2, and 520B3 so as to generate the second enhanced partial image. In an embodiment, the one or more super resolution algorithms may be applied to the partial images 520B1, 520B2, and 520B3 by the image sensor 490.
In an embodiment, similarly, a third enhanced partial image (not shown) of the object 510 may be generated from the partial images 520C1, 520C2, and 520C3. In an embodiment, one or more super resolution algorithms may be applied to the partial images 520C1, 520C2, and 520C3 so as to generate the third enhanced partial image. In an embodiment, the one or more super resolution algorithms may be applied to the partial images 520C1, 520C2, and 520C3 by the image sensor 490.
In an embodiment, the first enhanced partial image, the second enhanced partial image, and the third enhanced partial image of the object 510 may be stitched to form a stitched image 520 (
In step 620, for i=1, . . . , M, during the radiation pulse (i) and utilizing radiation of the radiation pulse (i), partial images (i,j), j=1, . . . , Ni of the scene may be captured one by one with a same image sensor, wherein Ni, i=1, . . . , M are all integers greater than 1. For example, for i=1, during the first radiation pulse and utilizing radiation of the first radiation pulse, the partial images 520A1, 520A2, and 520A3 are captured one by one with the image sensor 490. For i=2, during the second radiation pulse and utilizing radiation of the second radiation pulse, the partial images 520B1, 520B2, and 520B3 are captured one by one with the image sensor 490. For i=3, during the third radiation pulse and utilizing radiation of the third radiation pulse, the partial images 520C1, 520C2, and 520C3 are captured one by one with the image sensor 490.
In step 630, for i=1, . . . , M, an enhanced partial image (i) may be generated from the partial images (i,j), j=1, . . . , Ni by applying one or more super resolution algorithms. For example, for i=1, the first enhanced partial image is generated from the partial images 520A1, 520A2, and 520A3 by applying one or more super resolution algorithms to the partial images 520A1, 520A2, and 520A3. For i=2, the second enhanced partial image is generated from the partial images 520B1, 520B2, and 520B3 by applying one or more super resolution algorithms to the partial images 520B1, 520B2, and 520B3. For i=3, the third enhanced partial image is generated from the partial images 520C1, 520C2, and 520C3 by applying one or more super resolution algorithms to the partial images 520C1, 520C2, and 520C3.
In step 640, the enhanced partial images (i), i=1, . . . , M may be stitched resulting in a stitched image of the scene. For example, the first, second, and third enhanced partial images are stitched resulting in the stitched image 520 (
In an embodiment, with respect to step 620 of the flowchart 600 of
In an embodiment, with respect to the flowchart 600 of
In an embodiment, with respect to
In an embodiment, with reference to
For example, a radiation ray 722 which is aimed at the object 510 but not aimed at the active areas 190a and 190b of the image sensor 490 is prevented by a radiation blocking region 712 of the mask 710 from reaching the object 510. For another example, a radiation ray 724 which is aimed at the object 510 and also aimed at the active areas 190a and 190b of the image sensor 490 is allowed by a radiation passing region 714 of the mask 710 to pass through the mask 710 so as to reach the object 510.
In an embodiment, the distance between the first and third imaging positions may be less than a width 152 (
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 are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
Number | Date | Country | |
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Parent | PCT/CN2020/131473 | Nov 2020 | US |
Child | 18196010 | US |