Imaging system and method of operation thereof

Abstract

Disclosed herein is a method comprising: for i = 1,..., N, exposing a pixel (i) (150) of a same radiation detector (100) to a radiation (i), thereby causing an apparent signal (i) in the pixel (i) (150), wherein the pixel (i) (150) is at a temperature (i) while the pixel (i) (150) is exposed to the radiation (i); for i = 1,..., N, determining the temperature (i) of the pixel (i) (150); and for i = 1,..., N, determining an actual value (i) of a same radiation property of the radiation (i) from the apparent signal (i) and the temperature (i), wherein N is a positive integer. The radiation property can be a radiation intensity, a radiation phase, or a radiation polarization.

Description

[Technical Field]

[0001] The disclosure in this article relates to radiation detectors. [Background Technology]

[0002] A radiation detector is a device for measuring the properties of radiation. Examples of these properties may include the spatial distribution of the radiation's intensity, phase, and polarization. The radiation may be radiation that interacts with an object. For example, the radiation measured by the radiation detector may be radiation that has already passed through or been reflected from an object. The radiation may be electromagnetic radiation, such as infrared, visible, ultraviolet, X-rays, or gamma rays. The radiation may also be other types, such as alpha and beta rays. Radiation may include radiating particles, such as photons (electromagnetic waves) and subatomic particles. [Summary of the Invention]

[0003] This document discloses a method comprising: exposing a pixel (i) of the same radiation detector to radiation (1,i) for i = 1, ..., N, thereby inducing an apparent signal (1,i) in the pixel (i), wherein the pixel (i) is at a temperature (1,i) when exposed to the radiation (1,i); determining the temperature (1,i) of the pixel (i) for i = 1, ..., N; and determining the actual intensity (1,i) of the radiation (1,i) based on the apparent signal (1,i) and the temperature (1,i) for i = 1, ..., N, where N is a positive integer.

[0004] According to the example, N is greater than 1.

[0005] According to an embodiment, the method further includes: exposing the pixel (i) to radiation (2,i) for i = 1, ..., N, thereby inducing an apparent signal (2,i) in the pixel (i), wherein the pixel (i) is at temperature (2,i) when exposed to the radiation (2,i); determining the temperature (2,i) of the pixel (i) for i = 1, ..., N; and determining the actual intensity (2,i) of the radiation (2,i) based on the apparent signal (2,i) and the temperature (2,i) for i = 1, ..., N.

[0006] According to an embodiment, determining the temperature (1, i), i = 1, ..., N, includes measuring the temperature (1, i), i = 1, ..., N, using Q thermometers distributed throughout the radiation detector, where Q is a positive integer.

[0007] According to the embodiment, Q = N, and the Q thermometers are placed one-to-one at the pixel (i), i = 1, ..., N.

[0008] According to an embodiment, Q < N, and the determination of the temperature (1, i), i = 1,..., N, involves interpolation.

[0009] According to an embodiment, the method further comprises, for i = 1,..., N, determining (A) the actual intensity (i) of the radiation (i) incident on the pixel (i), (B) the apparent signal (i) caused by the radiation (i) in the pixel (i), and (C) the relationship (i) between the temperature (i) of the pixel (i) when the radiation (i) is incident on the pixel (i), wherein for i = 1,..., N, the determination of the actual intensity (1, i) is performed using the relationship (i).

[0010] According to an embodiment, the determination of the relationship (i), i = 1,..., N, comprises: for i = 1,..., N, a general formula (i) expressing the actual intensity (i) in terms of the apparent signal (i) and the temperature (i), each general formula (i), i = 1,..., N, having M coefficients, thus obtaining MxN coefficients, where M is a positive integer; for i = 1,..., N, acquiring experimental data of the actual intensity (i), the apparent signal (i), and the temperature (i); substituting the experimental data into the general formula (i), i = 1,..., N, thus obtaining MxN equations for the MxN coefficients; solving the MxN equations for the MxN coefficients; and substituting the values of the MxN coefficients into the general formula (i), i = 1,..., N, to obtain specific formulas (i) for the actual intensity (i), i = 1,..., N, expressed in terms of the apparent signal (i), i = 1,..., N, and the temperature (i), i = 1,..., N, respectively, and wherein for i = 1,..., N, the use of the relationship (i) includes using the specific formula (i).

[0011] According to an embodiment, the determination of the relationship (i), i = 1,..., N, comprises obtaining experimental data of the actual intensity (i), the apparent signal (i), and the temperature (i) for i = 1,..., N by exposing the pixels (i), i = 1,..., N, to radiation of M known intensities.

[0012] According to an embodiment, each of the M radiations has a uniform intensity throughout the pixels (i), i = 1,..., N.

[0013] According to an embodiment, the radiation among the M radiations has zero intensity throughout the pixels (i), i = 1,..., N.

[0014] According to an embodiment, determining the temperature (1, i), i = 1, ..., N, includes: for i = 1, ..., N, exposing the pixel (i) to radiation (3, i) of known actual intensity (3, i), thereby generating an apparent signal (3, i) in the pixel (i); for i = 1, ..., N, determining the temperature (3, i) of the pixel (i) based on the actual intensity (3, i) and the apparent signal (3, i) using the relation (i); and for i = 1, ..., N, using the temperature (3, i) as the value of the temperature (1, i).

[0015] According to an embodiment, the exposure of the pixel (i) to the radiation (3, i) is performed substantially before or after the exposure of the pixel (i) to the radiation (1, i).

[0016] This document discloses a method comprising: exposing a pixel (i) of the same radiation detector to radiation (1,i) for i = 1, ..., N, thereby inducing an apparent signal (1,i) in the pixel (i), wherein the pixel (i) is at a temperature (1,i) when exposed to the radiation (1,i); determining the temperature (1,i) of the pixel (i) for i = 1, ..., N; and determining, for i = 1, ..., N, an actual value (1,i) of the same radiation characteristic of the radiation (1,i) based on the apparent signal (1,i) and the temperature (1,i), wherein N is a positive integer.

[0017] According to an embodiment, the radiation characteristics are radiation intensity, radiation phase, or radiation polarization.

[0018] According to the example, N is greater than 1.

[0019] According to an embodiment, the method further includes: exposing the pixel (i) to radiation (2,i) for i = 1, ..., N, thereby inducing an apparent signal (2,i) in the pixel (i), wherein when the pixel (i) is exposed to the radiation (2,i), the pixel (i) is at a temperature (2,i); determining the temperature (2,i) of the pixel (i) for i = 1, ..., N; and determining, for i = 1, ..., N, an actual value (2,i) of the radiation characteristic of the radiation (2,i) based on the apparent signal (2,i) and the temperature (2,i).

[0020] According to an embodiment, determining the temperature (1, i), i = 1, ..., N, includes measuring the temperature (1, i), i = 1, ..., N, using Q thermometers distributed throughout the radiation detector, where Q is a positive integer.

[0021] According to an embodiment, Q = N, and wherein the Q thermometers are placed one-to-one at the pixels (i), i = 1, …, N.

[0022] According to an embodiment, Q < N, and wherein the determination of the temperature (1, i), i = 1, …, N, involves interpolation.

[0023] According to an embodiment, the method further comprises, for i = 1, …, N, determining (A) the actual value (i) of the radiation characteristic of the radiation (i) incident on the pixel (i), (B) the apparent signal (i) caused by the radiation (i) in the pixel (i), and (C) the relationship (i) between the temperature (i) of the pixel (i) when the radiation (i) is incident on the pixel (i), wherein for i = 1, …, N, the determination of the actual value (1, i) is performed using the relationship (i).

[0024] According to an embodiment, the determination of the relationship (i), i = 1, …, N, comprises: for i = 1, …, N, a general formula (i) expressing the actual value (i) in terms of the apparent signal (i) and the temperature (i), each general formula (i), i = 1, …, N, having M coefficients, thus obtaining M×N coefficients, where M is a positive integer; for i = 1, …, N, obtaining experimental data of the actual value (i), the apparent signal (i), and the temperature (i); substituting the experimental data into the general formula (i), i = 1, …, N, thus obtaining M×N equations for the M×N coefficients; solving the M×N equations for the M×N coefficients; and substituting the values of the M×N coefficients into the general formula (i), i = 1, …, N, to obtain specific formulas (i) for the actual value (i), i = 1, …, N, expressed respectively in terms of the apparent signal (i), i = 1, …, N, and the temperature (i), i = 1, …, N, and wherein for i = 1, …, N, the use of the relationship (i) includes using the specific formula (i).

[0025] According to an embodiment, the determination of the relationship (i), i = 1, …, N, comprises: by exposing the pixels (i), i = 1, …, N, to M radiations with known values of the radiation characteristic, thus obtaining experimental data of the actual value (i), the apparent signal (i), and the temperature (i) for i = 1, …, N.

[0026] According to an embodiment, each of the M radiations has a uniform intensity of the radiation characteristic throughout the pixels (i), i = 1, …, N.

[0027] According to an embodiment, the radiation in the M radiations has a zero value of the radiation characteristic over the entire pixel (i), i = 1, ..., N.

[0028] According to an embodiment, determining the temperature (1, i), i = 1, ..., N, includes: for i = 1, ..., N, exposing the pixel (i) to radiation (3, i) of a known actual value (3, i) of the radiation characteristics, thereby generating an apparent signal (3, i) in the pixel (i); for i = 1, ..., N, determining the temperature (3, i) of the pixel (i) based on the actual value (3, i) and the apparent signal (3, i) using the relation (i); and for i = 1, ..., N, using the temperature (3, i) as the value of the temperature (1, i).

[0029] According to an embodiment, the exposure of the pixel (i) to the radiation (3, i) is performed substantially before or after the exposure of the pixel (i) to the radiation (1, i). [Attached Image Description]

[0030] Figure 1 This illustration shows a radiation detector according to an embodiment.

[0031] Figure 2A A simplified cross-sectional view of the radiation detector according to an embodiment is shown.

[0032] Figure 2B A detailed cross-sectional view of the radiation detector according to an embodiment is shown schematically.

[0033] Figure 2C An alternative detailed cross-sectional view of the radiation detector according to an embodiment is shown schematically.

[0034] Figure 3 An imaging system according to an embodiment is illustrated.

[0035] Figure 4 A flowchart illustrating the operation of the imaging system according to an embodiment is shown.

[0036] Figure 5 Another flowchart summarizing and generalizing the operation of the imaging system according to an embodiment is shown.

Detailed Implementation Methods

[0037] Figure 1 The diagram schematically illustrates a radiation detector 100 as an example. The radiation detector 100 may include an array of pixels 150. This array may be a rectangular array (e.g., Figure 1 (As shown), cellular array, hexagonal array, or any other suitable array. Figure 1In the example described, the array of pixels 150 has 4 rows and 7 columns. However, typically the array of pixels 150 can have any number of rows and any number of columns.

[0038] Each pixel 150 can be configured to detect radiation incident upon it from a radiation source and can be configured to measure characteristics of the radiation (e.g., the energy, wavelength, radiant flux, and frequency of the radiating particles). For example, each pixel 150 can be configured to count the number of radiating particles incident upon it over a period of time, whose energy falls into multiple energy boxes. All of the pixels 150 can be configured to count the number of radiating particles incident upon it in multiple energy boxes within the same time period. When the incident radiating particles have similar energies, the pixel 150 can be simply configured to count the number of radiating particles incident upon it over a period of time without measuring the energy of each individual radiating particle.

[0039] Each pixel 150 may have its own analog-to-digital converter (ADC) configured to digitize an analog signal representing the energy of an incident radiating particle into a digital signal, or to digitize an analog signal representing the total energy of multiple incident radiating 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 radiating particle, another pixel 150 may be waiting for the radiating particle to arrive. The pixels 150 need not be individually addressable.

[0040] The radiation detector 100 described herein can be used in applications such as X-ray telescopes, mammography, industrial X-ray defect detection, X-ray microscopy or photomicrography, X-ray casting inspection, X-ray non-destructive testing, X-ray welding inspection, and X-ray digital subtraction angiography. The radiation detector 100 can also be used in place of photographic film, photographic film, photoexcited phosphors, X-ray image intensifiers, scintillators, or X-ray detectors. The radiation detector 100 can also be used as an image sensor to detect visible light photons containing images of objects or scenes.

[0041] Figure 2A Schematic illustration according to an embodiment Figure 1 A simplified cross-sectional view of a radiation detector 100 along line 2A-2A. More specifically, the 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 electrical signals of incident radiation generated in the radiation-absorbing layer 110. The detector 100 may or may not include a scintillator (not shown). The radiation-absorbing layer 110 may include a semiconductor material such as silicon, germanium, gallium arsenide, cadmium telluride, zinc cadmium telluride, or combinations thereof. The semiconductor material may have a high mass attenuation coefficient for the radiation of interest.

[0042] Figure 2B This is illustrated as an example. Figure 1 A detailed cross-sectional view of the radiation detector 100 along line 2A-2A. More specifically, the radiation absorption layer 110 may include one or more diodes (e.g., pin or pn) consisting of one or more discrete regions 114 of a first doped region 111 and a 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 are 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 have opposite types of doping (e.g., region 111 is p-type and region 113 is n-type, or region 111 is n-type and region 113 is p-type). Figure 2B In the example, each discrete region 114 of the second doped region 113, together with the first doped region 111 and the optional intrinsic region 112, forms a diode. That is, in Figure 2B In the example, the radiation-absorbing layer 110 includes a plurality of diodes (more specifically, seven diodes corresponding to...). Figure 1 The array contains 7 pixels 150 in one row. The plurality of diodes have electrical contacts 119A as a shared electrode. The first doped region 111 may also have discrete portions.

[0043] 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 circuitry such as filter networks, amplifiers, integrators, comparators, or digital circuitry such as microprocessors and memory. The electronic system 121 may include one or more 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 across all pixels 150. The electronic system 121 may be electrically connected to the pixels 150 via vias 131. The space between the vias may be filled with a filler material 130, which may increase the mechanical stability of the connection between the electronics layer 120 and the radiation-absorbing layer 110. Other bonding techniques may allow the electronic system 121 to be connected to the pixels 150 without using the vias 131.

[0044] When radiation from the radiation source (not shown) impacts the radiation-absorbing layer 110 of the diode, the radiation particles can be absorbed and generate one or more charge carriers (e.g., electrons, holes) through several mechanisms. These charge carriers can drift toward an electrode of one of the diodes under an electric field. The electric field can be an external electric field. The electrical contact 119B may include discrete portions, each of which is in electrical contact with the discrete region 114. The term "electrical contact" is used interchangeably with the term "electrode." In an embodiment, the charge carriers can drift in different directions such that the charge carriers generated by a single radiation particle are substantially not shared by the two different discrete regions 114 ("substantially not shared" here means less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of these charge carriers flow toward 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 not shared by the other discrete region 114. A pixel 150 associated with a discrete region 114 can be a region surrounding the discrete region 114 into which substantially all (more than 98%, more than 99.5%, more than 99.9%, or more than 99.99%) of the charge carriers generated by a radiating particle incident therein flow. 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 150.

[0045] Figure 2C Schematic illustration according to an embodiment Figure 1 An alternative detailed cross-sectional view of the radiation detector 100 along line 2A-2A. More specifically, the radiation absorbing layer 110 may comprise a resistor, but not a diode, of a semiconductor material such as silicon, germanium, gallium arsenide, cadmium telluride, zinc cadmium telluride, or a combination thereof. The semiconductor material may have a high mass attenuation coefficient for the radiation of interest. In an embodiment, Figure 2C The electronic device layer 120 described therein is similar in structure and function to Figure 2B The electronic device layer 120 in the middle.

[0046] When the radiation impacts the radiation-absorbing layer 110, which includes the resistor but not the diode, the radiation can be absorbed and generate one or more charge carriers through several mechanisms. A single radiating particle can generate 10 to 100,000 charge carriers. These charge carriers can drift towards electrical contacts 119A and 119B under an electric field. The electric field can be an external electric field. Electrical contact 119B includes discrete portions. In an embodiment, the charge carriers can drift in different directions such that the charge carriers generated by a single radiating particle are substantially not shared by the two distinct discrete portions of electrical contact 119B (“substantially not shared” 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 portion that is different from the remaining charge carriers). Charge carriers generated by radiating particles incident around the footprint of one of the discrete portions of electrical contact 119B are substantially not shared by the other discrete portion of electrical contact 119B. A pixel 150 associated with one of the discrete portions of the electrical contact 119B can be a region surrounding the discrete portion into which 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 radiating particles flow. That is, less than 2%, less than 0.5%, less than 0.1%, or less than 0.01% of the charge carriers flow outside the pixel associated with one of the discrete portions of the electrical contact 119B.

[0047] Figure 3 An imaging system 300 according to an embodiment is illustrated. In an embodiment, the imaging system 300 may include the radiation detector 100 and a computer 310 electrically connected to the radiation detector 100.

[0048] In an embodiment, the formula determination process for the imaging system 300 can be performed as follows. The first step may be to specify the radiation characteristics (e.g., intensity, phase, or polarization) measured using the imaging system 300. For example, it is assumed that the radiation intensity is specified as the radiation characteristic measured using the imaging system 300.

[0049] Next, in the embodiments, a general formula for the actual intensity can be specified for each of the 28 pixels 150. Specifically, for i = 1, ..., 28, the general formula for the actual intensity of the pixel (i) can be {Ri = (1 + ai x Ti) x Si + bi x Ti} (referred to as formula Fi_abST), where Ri is the actual intensity of the radiation (i) incident on the pixel (i). Si is the apparent signal caused by the radiation (i) in the pixel (i); Ti is the temperature of the pixel (i) when it is exposed to the radiation (i); and ai and bi are two constants. In essence, Fi_abST is the Ri formula expressed in terms of Si and Ti.

[0050] More specifically, the general formula for the actual intensity of pixel (1) can be {R1=(1+a1xT1)xS1+b1xT1} (referred to as formula F1_abST), the general formula for the actual intensity of pixel (2) can be {R2=(1+a2xT2)xS2+b2xT2} (referred to as formula F2_abST), and so on... and the general formula for the actual intensity of pixel (28) can be {R28=(1+a28xT28)xS28+b28xT28} (referred to as formula F28_abST).

[0051] Next, in an embodiment, in order to determine the values ​​of the 56 coefficients ai and bi, i = 1, ..., 28, in the 28 general formulas Fi_abST, i = 1, ..., 28, the radiation detector 100 (including the 28 pixels 150) can be set to a certain temperature, for example, T1 = T2 = ... = T28 = 25. The specific values ​​used in this description (e.g., a temperature of 25) are for illustrative purposes only and do not imply actual conditions (therefore, units are not shown).

[0052] Next, in an embodiment, the 28 pixels 150 are at the temperature (i.e., T1 = T2 = ... = T28 = 25°C), and the 28 pixels 150 can be exposed to a first radiation of known actual intensity for each pixel 150, for example, R1 = R2 = ... = R28 = 20°C, thereby generating 28 apparent signals S1, S2, ... and S28 in pixels (1), (2), ... and (28), respectively. The 28 values ​​of these 28 apparent signals S1, S2, ... and S28 can be read by the electronics layer 120 of the radiation detector 100 and then transmitted to the computer 310 for further processing.

[0053] Assume that, as described above, when T1 = T2 = ... = T28 = 25, R1 = R2 = ... = R28 = 20, resulting in S1 = 51, S2 = 52, ... and S28 = 53 (for simplicity, only three specific values ​​51, 52 and 53 are provided to pixels (1), (2) and (28) respectively). The 28 experimental data points of R, S, and T can be substituted into the above 28 general formulas F1_abST, F2_abST, ... and F28_abST to obtain 28 equations with 56 coefficients ai and bi, i = 1, ..., 28, namely: {20 = (1 + 25a1) x 51 + 25b1} (called equation E1A), {20 = (1 + 25a2) x 52 + 25b2} (called equation E2A), ... and {20 = (1 + 25a28) x 53 + 25b28} (called equation E28A).

[0054] Next, in an embodiment, while the 28 pixels 150 are still at the temperature (i.e., T1 = T2 = ... = T28 = 25), the 28 pixels 150 can be exposed to a second radiation of known actual intensity for each pixel 150, for example, R1 = R2 = ... = R28 = 0 (i.e., the second radiation is total darkness, and there is no incident radiation for each of the 28 pixels 150), thereby generating 28 apparent signals S1, S2, ..., and S28 in pixels (1), (2), ..., and (28), respectively. The 28 values ​​of these 28 apparent signals S1, S2, ..., and S28 can be read by the electronics layer 120 of the radiation detector 100 and then transmitted to the computer 310 for further processing.

[0055] Assume that, as described above, when T1 = T2 = ... = T28 = 25, R1 = R2 = ... = R28 = 0, resulting in S1 = 41, S2 = 43, ... and S28 = 45 (for simplicity, only three specific values ​​41, 43 and 45 are provided to pixels (1), (2) and (28) respectively). The 28 experimental data points of R, S, and T can be substituted into the above 28 general formulas F1_abST, F2_abST, ... and F28_abST to obtain 28 equations with 56 coefficients ai and bi, i = 1, ..., 28, namely: {0 = (1 + 25a1) x 41 + 25b1} (called equation E1B), {0 = (1 + 25a2) x 43 + 25b2} (called equation E2B), ... and {0 = (1 + 25a28) x 45 + 25b28} (called equation E28B).

[0056] Next, in the embodiment, the system of two linear equations E1A and E1B for the two unknowns a1 and b1 (i.e., {20=(1+25a1)x51+25b1} and {0=(1+25a1)x41+25b1}) can be solved for a1 and b1, yielding a1=0.04 and b1=-3.28. These specific a1 and b1 values ​​can be substituted into the general formula F1_abST for the pixel (1) to obtain a specific formula (called formula F1_ST) for the actual intensity of pixel (1) {R1=(1+0.04xT1)xS1-3.28xT1}.

[0057] Similarly, in the embodiment, the system of two linear equations E2A and E2B for the two unknowns a2 and b2 (i.e., {20 = (1 + 25a1) x 52 + 25b1} and {0 = (1 + 25a1) x 43 + 25b1}) can be solved for a2 and b2, yielding a2 = 0.05 and b2 = -3.82. These specific values ​​of a2 and b2 can be substituted into the general formula F2_abST for the pixel (2) to obtain a specific formula (referred to as formula F2_ST) for the actual intensity of pixel (2) {R2 = (1 + 0.05 x T2) x S2 - 3.82 x T2}.

[0058] Similarly, in the embodiment, the system of two linear equations E28A and E28B for the two unknowns a28 and b28 (i.e., {20 = (1 + 25a28) x 53 + 25b28} and {0 = (1 + 25a28) x 45 + 25b28}) can be solved for a28 and b28, yielding a28 = 0.06 and b28 = -4.5. These specific a28 and b28 values ​​can be substituted into the general formula F28_abST for the pixel (28) to obtain a specific formula (referred to as formula F28_ST) for the actual intensity of the pixel (28) {R28 = (1 + 0.06 x T28) x S2 - 4.5 x T28}.

[0059] The specific formulas for the 25 actual intensities of the remaining 25 pixels 150 (i.e., pixels (3), (4), ..., and (27)) can be determined in a similar manner. As a result of the above formula determination process, the 28 specific formulas for the actual intensities Fi_ST, i = 1, ..., 28, of the 28 pixels 150 of the radiation detector 100 are determined.

[0060] Next, in an embodiment, after the formula determination process of the imaging system 300 as described above is executed, the imaging processing of the imaging system 300 can be performed as follows. First, in an embodiment, the 28 pixels 150 of the radiation detector 100 can be exposed to radiation from an object or scene (i.e., the radiation detector 100 is used to capture an apparent image of the object / scene), thereby generating 28 apparent signals S1, S2, ..., S28 in the 28 pixels 150. These 28 apparent signals S1, S2, ..., S28 in the 28 pixels 150 constitute the apparent image of the object / scene. The 28 values ​​of the 28 apparent signals S1, S2, ..., S28 can be acquired for subsequent use in the 28 specific formulas Fi_ST, i = 1, ..., 28.

[0061] Next, in an embodiment, 28 values ​​of Ti,i = 1, ..., 28 can be obtained by measuring Ti,i = 1, ..., 28 using 28 thermometers (not shown). In an embodiment, the 28 thermometers can be positioned one-to-one at the 28 pixels 150. Next, in an embodiment, the specific values ​​of 56 Si and Ti,i = 1, ..., 28 obtained as described above can be substituted into the 28 specific formulas F1_ST, F2_ST, ..., F28_ST to determine the 28 actual intensities Ri,i = 1, ..., 28 of the 28 pixels 150.

[0062] It should be noted that the 28 values ​​of Ri, i = 1, ..., 28 constitute the actual image of the object / scene, while the 28 values ​​of Si, i = 1, 2, 3, constitute the apparent image of the object / scene. In the example above, it can be said that the actual image of the object / scene is determined based on the apparent image of the object / scene and the temperature of the 28 pixels 150 when the apparent image was captured, using 28 specific formulas of actual intensities F1_ST, F2_ST, ..., F28_ST.

[0063] Figure 4 The imaging system 300 is summarized according to an embodiment. Figure 3 The flowchart 400 shows the formula determination process and the imaging process. Specifically, in step A1 of the formula determination process, in the embodiment, radiation characteristics can be specified. In the example above, radiation intensity is specified.

[0064] Next, in step A2 of the formula determination process, in an embodiment, a general formula for the actual intensity of each pixel 150 can be specified. In the example above, for i = 1, ..., 28, the general formula for the actual intensity of pixel (i) is {Ri = (1 + aixTi)xSi + bixTi} (i.e., Fi_abST).

[0065] Next, in step A3 of the formula determination process, in an embodiment, experimental data can be acquired such that for i = 1, ..., 28, the number of experimental data points for Ri, Si, and Ti of the acquired pixel (i) is equal to the number M of coefficients in the general formula for the actual intensity Ri. In the example above, since {Ri = (1 + aixTi)xSi + bixTi} has two coefficients ai and bi (i.e., M = 2), two experimental data points for Ri, Si, and Ti of the pixel (i) are acquired. A total of M x N experimental data points for R, S, and T are acquired (where M = 2, N = number of pixels = 28).

[0066] Next, in step A4 of the formula determination process, in this embodiment, a specific formula for the radiation intensity of each pixel 150 can be determined. Specifically, the experimental data (M x N experimental data points) obtained in step A3 can be substituted into the N general formulas (i.e., Fi_abST, i = 1, ..., N) for the actual intensity of the N pixels 150, resulting in M ​​x N equations with M x N coefficients ai and bi, i = 1, ..., N. These M x N equations can be solved to obtain the values ​​of the M x N coefficients (where, in the example above, M = 2, N = 28). These M x N values ​​of the M x N coefficients ai and bi, i = 1, ..., N, can be substituted into the N general formulas Fi_abST, i = 1, ..., N, thereby obtaining the N specific formulas Fi_ST, i = 1, ..., N for the actual intensity of the N pixels 150 (where, in the example above, M = 2, N = 28).

[0067] In the example above, for i = 1, ..., 28, the Ri, Si, and Ti experimental data points of the two acquired pixels (i) are inserted into the general formula Fi_abST to derive two equations for ai and bi, and then the values ​​of ai and bi are solved. The resulting values ​​of ai and bi are then inserted into the general formula Fi_abST to derive the specific formula Fi_ST for pixel (i). For example, as described above, the F1_ST for pixel (1) is R1 = (1 + 0.04xT1)xS1 - 3.28xT1}.

[0068] Next, in an embodiment, in step B1 of the imaging process, the radiation detector 100 may be used to capture an apparent image of the object / scene. The captured apparent image of the object / scene provides 28 values ​​for the 28 apparent signals Si, i = 1, ..., 28.

[0069] Next, in step B2 of the imaging process, in this embodiment, 28 temperatures Ti, i = 1, ..., 28, of the 28 pixels 150 can be obtained. In the example above, the values ​​of the 28 Ti, i = 1, ..., 28, of the 28 pixels 150 are obtained by using the 28 thermometers at the 28 pixels 150.

[0070] Next, in step B3 of the imaging process, in an embodiment, the actual image of the object / scene can be determined based on the captured apparent image of the object / scene and the temperature of the 28 pixels 150. In the example above, 28 values ​​of Ri, i = 1, ..., 28 are determined using the 28 specific formulas Fi_ST, i = 1, ..., 28. The 28 values ​​of Ri, i = 1, ..., 28 of the 28 pixels 150 constitute the actual image of the object / scene.

[0071] Figure 5 The imaging system 300 described in the embodiments is illustrated in summary and generalization. Figure 3 A flowchart 500 of the imaging process of the radiation detector 100 is provided. In step 510, for i = 1, ..., N (N is a positive integer), a pixel (i) of the radiation detector 100 can be exposed to radiation (i), thereby causing an apparent signal (i) in the pixel (i), wherein the pixel (i) is at a temperature (i) when the pixel (i) is exposed to the radiation (i). In step 520, for i = 1, ..., N, the temperature (i) of the pixel (i) can be determined. In an embodiment, the temperature (i), i = 1, ..., N, can be determined by using N thermometers placed one-to-one at the pixel (i), i = 1, ..., N. In step 530, for i = 1, ..., N, the actual intensity (i) of the radiation (i) can be determined based on the apparent signal (i) and the temperature (i). The N actual intensities (i), i = 1, ..., N, constitute the actual image of the object / scene.

[0072] In the above embodiments, the formula determination process and the imaging process were described for the case where the radiation detector 100 has 28 pixels 150. Generally, the above formula determination process and imaging process can be used for cases where the radiation detector 100 has any number of pixels 150.

[0073] In the above embodiments, radiation intensity is the radiation characteristic of interest. Generally, any radiation characteristic (e.g., intensity, phase, or polarization) can be designated as the radiation characteristic of interest.

[0074] In the above embodiments, for pixel (i), a specific formula for the actual intensity Fi_ST is used to represent the relationship between Ri, Si, and Ti (e.g., for pixel (i), {R1 = (1 + 0.04xT1)xS1 - 3.28xT1}). Generally, any form of relationship (e.g., formula, lookup table, graph, curve, etc.) can be used to represent the relationship between Ri, Si, and Ti of the pixel (i).

[0075] In the above embodiments, the general formula for the actual radiant intensity of pixel 150 has the form {I=(1+aT)S+bT}. Typically, the general formula for the actual radiant intensity of pixel 150 can have any form where S and T are used to represent R along with some constant coefficients. This is achieved through the formula determination process ( Figure 4 With sufficient experimental data points for R, S, and T obtained in step A3), these constant coefficients can be determined, and therefore can be used for each of the 28 pixels 150. Figure 4 Step A4) Determine a specific formula for determining the actual radiation intensity R in terms of the apparent signal S and temperature T.

[0076] In the above embodiments, in step A3 ( Figure 4 In the ), two selected known radiations have uniform intensity across the 28 pixels 150 (i.e., for the first selected known radiation, R1 = R2 = ... = R28 = 20, and for the second selected known radiation, R2 = ... = R28 = 0). Typically, the 28 values ​​of Ri, i = 1, ..., 28 for the selected known radiations do not need to be the same.

[0077] In the above embodiment, in step B2 ( Figure 4 In this embodiment, a thermometer located at each of the 28 pixels 150 is used to determine the temperature of the pixel when the apparent image is captured. In an alternative embodiment, fewer thermometers may be sparsely placed on the radiation detector 100 (i.e., the number of thermometers is less than the number of pixels 150), and the temperature of each pixel 150 may be inferred by interpolation.

[0078] In another alternative embodiment, the temperature of each pixel 150 when the apparent image is captured can be determined without a thermometer, as follows. In this embodiment, the apparent image of the object / scene described above is captured substantially immediately after or before the radiation detector 100 (note: "substantially immediately" means immediately or almost immediately after). The 28 pixels 150 of the radiation detector 100 can be exposed to radiation of known actual intensity (e.g., complete darkness with known actual intensity R1 = R2 = ... = R28 = 0), and the resulting 28 values ​​of Si, i = 1, ..., 28 can be obtained. Next, the 56 values ​​of Ri and Si, i = 1, ..., 28 can be input into step A4 ( Figure 4The 28 specific formulas Fi_ST determined in [reference to a specific formula] yield 28 unknown temperature equations for Ti,i = 1, ..., 28. These 28 temperature equations for Ti,i = 1, ..., 28 can be solved for 28 values ​​of the temperature Ti,i = 1, ..., 28 of the 28 pixels 150 when they are exposed to the known radiation (e.g., complete darkness in this example). However, since the actual exposure time of the 28 pixels 150 to the known radiation is close to the time when the apparent image of the object / scene is captured, the 28 temperature values ​​obtained by solving the above 28 temperature equations can be used as 28 temperatures of the 28 pixels 150 when the apparent image of the object / scene is captured.

[0079] In the above embodiments, reference is made to Figure 4 Step B2 is performed after step B1. Typically, if Ti, i = 1, ..., 28 is determined using the thermometer as described above, step B2 can be performed substantially at the same time as step B1 (i.e., simultaneously with step B1, or substantially before or after step B1). If Ti, i = 1, ..., 28 is determined using the alternative method described above (i.e., without a thermometer), step B2 can be performed sufficiently close to the time of step B1 (i.e., substantially immediately before or after step B1).

[0080] In the above embodiments, Figure 4 Steps B1-B3 are executed once. Typically, they can be executed multiple times. Figure 4 Steps B1-B3 in the process are used to identify multiple actual images of the same object / scene or different objects / scenes.

[0081] In the above embodiments, reference is made to Figure 4 The steps are performed in the order A1, A2, A3, A4, B1, B2, and B3. In an alternative embodiment, the steps may be performed in the order A1, B1, B2, A2, A3, A4, and B3, wherein step B2 may be performed using a thermometer. Other orders are also possible.

[0082] In the above embodiment, the radiation detector 100 includes 28 pixels 150 arranged in an array of 7 rows and 4 columns. Typically, the radiation detector 100 may include N pixels 150 arranged in any manner, where N is a positive integer.

[0083] 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 illustrative purposes and not restrictive, and their true scope and spirit should be determined by the claims herein.

Claims

1. A method of operating an imaging system, comprising: For i = 1,..., N, exposing pixel i of the same radiation detector to first radiation i, thereby causing a first apparent signal i in pixel i, where when pixel i is exposed to the first radiation i, pixel i is at a first temperature i; For i = 1,..., N, determining the first temperature i of pixel i; For i = 1,..., N, determining a first actual intensity i of the first radiation i based on the first apparent signal i and the first temperature i, where N is a positive integer; And For i = 1,..., N, determining a relationship i between (A) the actual intensity i of radiation i incident on pixel i, (B) the apparent signal i in pixel i caused by the radiation i, and (C) the temperature i of pixel i when the radiation i is incident on pixel i, where for i = 1,..., N, determining the first actual intensity i of the first radiation i is performed using the relationship i, where determining the first temperature i of pixel i, i = 1,..., N, includes: For i = 1,..., N, exposing pixel i to third radiation i of a known third actual intensity i, thereby generating a third apparent signal i in pixel i; For i = 1,..., N, using the relationship i to determine a third temperature i of pixel i based on the third actual intensity i and the third apparent signal i; and For i = 1,..., N, using the third temperature i as the value of the first temperature i.

2. The method according to claim 1, wherein N is greater than 1.

3. The method according to claim 1, further comprising: For i = 1,..., N, exposing pixel i to second radiation i, thereby causing a second apparent signal i in pixel i, where when pixel i is exposed to the second radiation i, pixel i is at a second temperature i; For i = 1,..., N, determining the second temperature i of pixel i; And For i = 1,..., N, determining a second actual intensity i of the second radiation i based on the second apparent signal i and the second temperature i.

4. The method according to claim 1, where determining the first temperature i of pixel i, i = 1,..., N, includes measuring the first temperature i using Q thermometers distributed across the radiation detector, and where Q is a positive integer.

5. The method according to claim 4, where Q = N, and where the Q thermometers are placed one-to-one at pixel i, i = 1,..., N.

6. The method according to claim 4, where Q < N, and where determining the first temperature i of pixel i, i = 1,..., N, involves interpolation.

7. The method according to claim 1, in, determining the relationship i, i = 1,..., N, includes: For i = 1, ..., N, a general formula i is used to represent the actual intensity i using the apparent signal i and the temperature i. Each of the general formulas i, i = 1, ..., N, has M coefficients, thus resulting in M ​​x N coefficients, where M is a positive integer. For i = 1, ..., N, obtain experimental data of the actual intensity i, the apparent signal i, and the temperature i; substitute the experimental data into the formula i, i = 1, ..., N, thus obtaining M x N equations with M x N coefficients; Solve the MxN equations with the given MxN coefficients; and Substituting the values ​​of the MxN coefficients into the formula i, i = 1, ..., N, yields specific formulas i, i = 1, ..., N for the actual intensity i, i = 1, ..., N, expressed in terms of the apparent signal i, i = 1, ..., N and the temperature i, i = 1, ..., N, respectively. Where for i = 1, ..., N, the use of the relation i includes the use of a specific formula i.

8. The method of claim 1, wherein determining the relation i, i = 1, ..., N, comprises obtaining experimental data of the actual intensity i, the apparent signal i, and the temperature i for i = 1, ..., N by exposing the pixel i, i = 1, ..., N, to M radiations of known intensities.

9. The method of claim 8, wherein each of the M radiations has a uniform intensity throughout the entire pixel i, i = 1, ..., N.

10. The method of claim 9, wherein one of the M radiations has zero intensity over the entire pixel i, i = 1, ..., N.

11. The method of claim 1, wherein, The pixel i is exposed to the third radiation i before or after the pixel i is exposed to the first radiation i.

12. A method of operating an imaging system, comprising: For i = 1, ..., N, a pixel i of the same radiation detector is exposed to a first radiation i, thereby causing a first apparent signal i in the pixel i, wherein the pixel i is at a first temperature i when it is exposed to the first radiation i; For i = 1, ..., N, determine the first temperature i of pixel i; and For i = 1, ..., N, a first actual value i of the same radiation characteristic of the first radiation i is determined based on the first apparent signal i and the temperature i. Where N is a positive integer; and For i = 1, ..., N, determine the relationship between (A) the actual value i of the radiation characteristic of the radiation i incident on the pixel i, (B) the apparent signal i in the pixel i caused by the radiation i, and (C) the temperature i of the pixel i when the radiation i is incident on the pixel i. Where for i = 1, ..., N, it is determined that the first actual value i is executed using the relation i. Determining the first temperature i, i = 1, ..., N, of pixel i includes: For i = 1, ..., N, the pixel i is exposed to a third radiation i of a third actual value i known to the radiation characteristics, thereby generating a third apparent signal i in the pixel i; For i = 1, …, N, use the relation i to determine the third temperature i of the pixel i based on the third actual value i and the third apparent signal i; and For i = 1, …, N, use the third temperature i as the value of the first temperature i.

13. The method according to claim 12, wherein the radiation characteristic is radiation intensity, radiation phase, or radiation polarization.

14. The method according to claim 12, wherein N is greater than 1.

15. The method according to claim 12, further comprising: For i = 1, …, N, expose the pixel i to a second radiation i, thereby causing a second apparent signal i in the pixel i, where the pixel i is at a second temperature i when the pixel i is exposed to the second radiation i; for i = 1, …, N, determine the second temperature i of the pixel i; And For i = 1, …, N, determine the second actual value i of the radiation characteristic of the second radiation i based on the second apparent signal i and the second temperature i.

16. The method according to claim 12 wherein the determining the first temperature i of the pixel i, i = 1, …, N, includes measuring the first temperature i, i = 1, …, N, using Q thermometers distributed throughout the radiation detector, and where Q is a positive integer.

17. The method according to claim 16 where Q = N, and where the Q thermometers are placed one-to-one at the pixels i, i = 1, …, N.

18. The method according to claim 16 where Q < N, and where the determining the first temperature i of the pixel i, i = 1, …, N, involves interpolation.

19. The method according to claim 12 in, determining the relation i, i = 1, …, N, includes: For i = 1, …, N, express the actual value i by a formula i in terms of the apparent signal i and the temperature i, each formula i, i = 1, …, N, having M coefficients, thus obtaining MxN coefficients, where M is a positive integer; for i = 1, …, N, obtain experimental data of the actual value i, the apparent signal i, and the temperature i; substitute the experimental data into the formula i, i = 1, …, N, thus obtaining MxN equations for the MxN coefficients; Solve the MxN equations for the MxN coefficients; and Substitute the values of the MxN coefficients into the formula i, i = 1, …, N, to obtain specific formulas i, i = 1, …, N, for the actual value i, i = 1, …, N, expressed in terms of the apparent signal i, i = 1, …, N, and the temperature i, i = 1, …, N, respectively, and where for i = 1, …, N, the use of the relation i includes using the specific formula i.

20. The method of claim 12, wherein, Determining the relation i, i = 1, …, N, includes obtaining experimental data of the actual value i, the apparent signal i, and the temperature i for i = 1, …, N, by exposing the pixels i, i = 1, …, N, to radiations with M known values of radiation characteristics.

21. The method of claim 20, wherein each of the M radiations has a uniform intensity of the radiation characteristic throughout the entire pixel i, i = 1, ..., N.

22. The method of claim 21, wherein the radiation in the M radiations has zero values ​​of the radiation characteristics over the entire pixel i, i = 1, ..., N.

23. The method of claim 12, wherein, The pixel i is exposed to the third radiation i before or after the pixel i is exposed to the first radiation i.

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