Dual-energy imaging devices and methods

Abstract

The aim is to provide an apparatus and method for detecting x-rays and / or gamma rays. According to an embodiment, the apparatus includes: a detector comprising a plurality of pixels, wherein the plurality of pixels includes a first subset of pixels configured to detect incident x-ray or gamma-ray radiation within a first energy range and a second subset of pixels configured to detect incident x-ray or gamma-ray radiation within a second energy range; and a processing unit configured to: obtain a signal from each of the plurality of pixels; obtain a radiation intensity value for each of the plurality of pixels based on the signal of each pixel; and calculate an estimated radiation intensity value for at least one pixel in the second subset within the first energy range. An apparatus and method are provided.

Description

Technical Field

[0001] This disclosure relates to on-site X-ray and gamma-ray detectors, and more specifically to an apparatus and method for X-ray and / or gamma-ray detection. Background Technology

[0002] In dual-energy imaging, the attenuation of electromagnetic radiation (such as X-rays) on an object can be obtained across two energy ranges. This information can then be used to generate a more detailed image of the object compared to using only a single energy range. Summary of the Invention

[0003] This summary is provided to introduce the selection of concepts in a simplified form, which will be further described in the following detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to limit the scope of the claimed subject matter.

[0004] The objective is to provide an apparatus and method for detecting X-rays and / or gamma rays. The above and other objectives are achieved through the features of the independent claims. Other embodiments are apparent from the dependent claims, the description, and the drawings.

[0005] According to a first aspect, an apparatus includes: a detector comprising a plurality of pixels, wherein the plurality of pixels includes a first subset of pixels configured to detect incident x-ray or gamma-ray radiation within a first energy range and a second subset of pixels configured to detect incident x-ray or gamma-ray radiation within a second energy range, wherein the second energy range is a subrange of the first energy range; and a processing unit coupled to the detector and configured to: acquire a signal from each of the plurality of pixels; calculate a radiation intensity value for each of the plurality of pixels based on the signal of each pixel; and calculate an estimated radiation intensity value for at least one pixel in the second subset within the first energy range using the acquired radiation intensity value of at least one pixel in the second subset and the acquired radiation intensity values ​​of at least two pixels in the first subset. For example, the apparatus can improve imaging resolution by estimating missing information within the first energy range.

[0006] In an embodiment of the first aspect, the processing unit is further configured to calculate the radiant intensity estimate by performing the following operations: calculating an attenuation factor for each of a plurality of pixel pairs, wherein each of the plurality of pixel pairs includes one pixel in a first subset of pixels and one pixel in a second subset of pixels; calculating a filtered attenuation factor using a spatial filter and the attenuation factors of the plurality of pixel pairs; and calculating the radiant intensity estimate within a first energy range using the obtained radiant intensity value of at least one pixel in the second subset and the filtered attenuation factor. For example, the device can efficiently calculate the estimate by using the attenuation factors of other pixels.

[0007] In another embodiment of the first aspect, the spatial filter includes a spatial low-pass filter, a moving average filter, a moving median filter, a weighted median filter, or a Gaussian filter. For example, the device can efficiently calculate the filtered attenuation factor.

[0008] In another embodiment of the first aspect, the processing unit is further configured to calculate an estimated radiant intensity value for at least one pixel in the first pixel subset within a second energy range using the obtained radiant intensity value of at least one pixel in the first pixel subset and the obtained radiant intensity values ​​of at least two pixels in the second pixel subset. For example, the device can further improve imaging resolution by estimating missing information within the second energy range.

[0009] In another embodiment of the first aspect, the detector further includes a filter arranged to prevent at least a portion of incident X-ray or gamma-ray radiation outside the second energy range from entering the second plurality of pixels. For example, this device can effectively prevent incident radiation outside the second energy range from entering the second plurality of pixels. Therefore, the second plurality of pixels can be used for dual-energy imaging.

[0010] In another embodiment of the first aspect, the filter further includes a plurality of apertures arranged to allow incident X-ray or gamma-ray radiation to enter a first plurality of pixels. For example, the device can allow radiation to enter the first plurality of pixels while preventing incident radiation outside a second energy range from entering a second plurality of pixels. Thus, the first plurality of pixels and the second plurality of pixels can be used for dual-energy imaging.

[0011] In another embodiment of the first aspect, the first and second subsets of pixels are arranged in an alternating pattern in space. For example, the device may use every other pixel to measure incident radiation in a first energy range and every other pixel to measure incident radiation in a second energy range.

[0012] According to the second aspect, the dual-energy X-ray or gamma-ray imaging apparatus includes the device according to the first aspect.

[0013] According to a third aspect, a method for imaging using a detector comprising a plurality of pixels is provided, wherein the plurality of pixels includes a first subset of pixels configured to detect incident X-ray or gamma-ray radiation within a first energy range and a second subset of pixels configured to detect incident X-ray or gamma-ray radiation within a second energy range, wherein the second energy range is a subrange of the first energy range. The method includes: obtaining a signal from each of the plurality of pixels; calculating a radiation intensity value for each of the plurality of pixels based on the signal of each pixel; and calculating a radiation intensity estimate for at least one pixel in the second subset within the first energy range using the obtained radiation intensity value of at least one pixel in the second subset and the obtained radiation intensity values ​​of at least two pixels in the first subset. For example, this method can improve imaging resolution by estimating missing information within the first energy range.

[0014] In a third embodiment, calculating the radiant intensity estimate includes: calculating an attenuation factor for each of a plurality of pixel pairs, wherein each of the plurality of pixel pairs includes one pixel in a first subset of pixels and one pixel in a second subset of pixels; calculating a filtered attenuation factor using a spatial filter and the attenuation factors of the plurality of pixel pairs; and calculating a radiant intensity estimate within a first energy range using the obtained radiant intensity value of at least one pixel in the second subset of pixels and the filtered attenuation factor. For example, this method can efficiently calculate the estimate by using the attenuation factors of other pixels.

[0015] In another embodiment of the third aspect, the spatial filter includes a spatial low-pass filter, a moving average filter, a moving median filter, a weighted median filter, or a Gaussian filter. For example, this method can efficiently calculate the filtered attenuation factor.

[0016] In another embodiment of the third aspect, the method further includes using the obtained radiance values ​​of at least one pixel in the first pixel subset and the obtained radiance values ​​of at least two pixels in the second pixel subset to calculate an estimated radiance value for at least one pixel in the first pixel subset within a second energy range. For example, the method can further improve imaging resolution by estimating missing information within the second energy range.

[0017] According to the fourth aspect, the computer program product includes program code configured to execute the method according to the third aspect when the computer program product is executed on a computer.

[0018] Many of the additional features will be easier to understand as they become clearer with reference to the following detailed description taken in conjunction with the accompanying drawings. Attached Figure Description

[0019] In the following, exemplary embodiments are described in more detail with reference to the accompanying figures and drawings, wherein:

[0020] Figure 1 The illustration shows a schematic diagram of a device according to an embodiment;

[0021] Figure 2 A schematic diagram of a detector according to an embodiment is shown;

[0022] Figure 3 A schematic diagram of a detector according to another embodiment is illustrated;

[0023] Figure 4 The illustration shows a schematic diagram of radiation intensity value estimation according to an embodiment;

[0024] Figure 5 The figure illustrates a graph representation of the TE and HE counts and the attenuation factor according to an embodiment;

[0025] Figure 6 The figure illustrates a graph representation of the TE and HE counts and the attenuation factor according to another embodiment;

[0026] Figure 7 The illustration shows a schematic diagram of the original, dark-corrected data as a grayscale image according to an embodiment.

[0027] Figure 8 The illustration shows a schematic diagram of an attenuation factor for a grayscale image according to an embodiment;

[0028] Figure 9 The illustration shows a schematic diagram of a filtered attenuation factor as a grayscale image according to an embodiment.

[0029] Figure 10 The illustration shows a schematic diagram of the restored TE output as a grayscale image according to an embodiment;

[0030] Figure 11 The illustration shows a schematic diagram of the restored HE output as a grayscale image according to an embodiment; and

[0031] Figure 12 A flowchart of a method according to an embodiment is illustrated.

[0032] In the following text, the same reference numerals refer to similar or at least functionally equivalent features. Detailed Implementation

[0033] In the following description, reference is made to the accompanying drawings, which form part of this disclosure, and which illustrate, by way of illustration, specific aspects of this disclosure that may be placed. It will be understood that other aspects may be utilized and structural or logical changes may be made without departing from the scope of this disclosure. Therefore, the following detailed description should not be construed as limiting, as the scope of this disclosure is defined by the appended claims.

[0034] For example, it should be understood that the disclosure of the described method can also be applied to a corresponding device or system configured to perform the method, and vice versa. For example, if specific method steps are described, the corresponding device may include a unit that performs the described method steps, even if that unit is not explicitly described or illustrated in the figures. On the other hand, for example, if a particular apparatus is described based on functional units, the corresponding method may include steps that perform the described functions, even if such steps are not explicitly described or illustrated in the figures. Furthermore, it should be understood that features of the various exemplary aspects described herein can be combined with each other unless otherwise specifically stated.

[0035] Figure 1 A schematic diagram of a device 100 according to an embodiment is shown.

[0036] According to an embodiment, device 100 includes detector 101, which includes a plurality of pixels. The plurality of pixels may include a first subset of pixels configured to detect incident X-ray or gamma-ray radiation within a first energy range and a second subset of pixels configured to detect incident X-ray or gamma-ray radiation within a second energy range. The second energy range may be a subrange of the first energy range.

[0037] Multiple pixels can be arranged in space, for example, in a one-dimensional row, a two-dimensional array, or a matrix.

[0038] The first energy range can correspond to, for example, the so-called total energy (TE) in dual-energy X-ray imaging.

[0039] The second energy range can correspond to, for example, the so-called high energy (HE) in dual-energy X-ray imaging. Since the HE energy range is a subrange of the TE energy range, device 100 can obtain so-called low energy (LE) information by subtracting the HE event from the TE event. In this way, device 100 can perform dual-energy imaging using both the LE and HE signals.

[0040] The device 100 may also include a processing unit 102 coupled to the detector 101. The processing unit 102 may be configured to obtain a signal from each of the plurality of pixels.

[0041] Processing unit 102 can preprocess signals obtained from multiple pixels. Then, processing unit 102 can use the preprocessed signals for continuous operations. For example, processing unit 102 can perform denoising and / or dark-frame subtraction.

[0042] The signal from each pixel can be proportional to the intensity of the incident radiation. For example, each signal can be proportional to the number of events that occur in the pixel due to the incident radiation.

[0043] The processing unit 102 can also be configured to obtain the radiation intensity value of each of the multiple pixels based on the signal of each pixel.

[0044] Processing unit 102 can obtain the radiation intensity value, for example, by performing analog-to-digital conversion on the signal and appropriately scaling the conversion result. Alternatively or additionally, processing unit 102 can perform other operations and / or calculations to obtain the radiation intensity value.

[0045] A radiation intensity value can correspond to the intensity of incident radiation at a pixel location. A radiation intensity value can also be referred to as an event count or the like. The obtained radiation intensity value can also be referred to as a measured radiation intensity value, a detected radiation intensity value, or the like.

[0046] The processing unit 102 may also be referred to as a signal processing unit, a computing unit, or a similar unit.

[0047] The processing unit 102 may also be configured to calculate an estimated value of the radiation intensity of at least one pixel in the second pixel subset within a first energy range using the obtained radiation intensity value of at least one pixel in the second pixel subset and the obtained radiation intensity values ​​of at least two pixels in the first pixel subset.

[0048] In some embodiments, the processing unit 102 may also be configured to calculate an estimated radiation intensity value for each pixel in the second pixel subset within a first energy range using the obtained radiation intensity value of each pixel in the second pixel subset and the obtained radiation intensity values ​​of at least two pixels in the first pixel subset.

[0049] Since the second subset of pixels can only detect incident radiation within a second energy range, intensity information of incident radiation within a first energy range at the location of pixels in the second subset may be lost. Therefore, the imaging resolution may be reduced. As disclosed above, device 100 can approximate the lost information by using imaging information from other pixels. Therefore, device 100 can improve imaging quality.

[0050] Each of the multiple pixels can, for example, be configured to detect incident x-rays and / or gamma-ray radiation near the pixel.

[0051] Processing unit 102 may, for example, be electrically coupled to each of a plurality of pixels. In some embodiments, processing unit 102 may be implemented as an application-specific integrated circuit (ASIC). In some other embodiments, the ASIC may be integrated with detector 101 into a single unit. In other embodiments, processing unit 102 may be implemented in a device separate from detector 101.

[0052] Processing unit 102 may include at least one processor. The at least one processor may include, for example, various processing devices such as a coprocessor, microprocessor, controller, digital signal processor (DSP), processing circuitry with or without an accompanying DSP, or various other processing devices including integrated circuits such as one or more of, for example, application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), microcontroller units (MCUs), hardware accelerators, dedicated computer chips, etc.

[0053] The processing unit 102 may also include a memory. The memory may be configured to store, for example, computer programs. The memory may include one or more volatile memory devices, one or more non-volatile memory devices, and / or a combination of one or more volatile memory devices and non-volatile memory devices. For example, the memory may be implemented as a magnetic storage device (such as a hard disk drive, floppy disk, magnetic tape, etc.), an optical storage device, or a semiconductor memory (such as a mask ROM, PROM (programmable ROM), EPROM (erasable PROM), flash ROM, RAM (random access memory), etc.).

[0054] Those skilled in the art will understand that when the processing unit 102 is configured to perform certain functions, one or more components of the processing unit 102, such as at least one processor and / or memory, can be configured to perform those functions. Furthermore, when at least one processor is configured to perform certain functions, those functions can be performed using, for example, program code included in memory.

[0055] The device 100 can be implemented in, for example, dual-energy X-ray or gamma-ray imaging devices.

[0056] Figure 2 A schematic diagram of a detector 101 according to an embodiment is shown.

[0057] According to an embodiment, detector 101 further includes filter 205, which is arranged to prevent at least a portion of incident x-ray or gamma-ray radiation 206 outside the second energy range from entering the second plurality of pixels 203.

[0058] According to an embodiment, the filter 205 further includes a plurality of apertures arranged to allow incident x-ray or gamma-ray radiation 206 to enter the first plurality of pixels 202.

[0059] For example, in Figure 2 In one embodiment, the plurality of pixels 201 includes a first subset of pixels 202 and a second subset of pixels 203. Each pixel in the second subset of pixels 203 is covered by a filter 205. Therefore, the filter 205 includes an aperture for the first plurality of pixels 202.

[0060] exist Figure 2 In one embodiment, the detector further includes a scintillator layer 204. The scintillator layer 204 can convert the incident radiation 206 into lower-energy electromagnetic radiation. This lower-energy electromagnetic radiation can then be detected, for example, by photodiodes corresponding to the plurality of pixels 201.

[0061] The filter 205 may include, for example, copper. The thickness of the filter 205 may be in the range of 0.1 to 10 millimeters (mm), for example, 1.5 mm.

[0062] Filter 205 may also be referred to as a high-energy filter, an X-ray filter, or the like.

[0063] Since the first pixel subset 202 is not covered by the filter 205 and the second pixel subset 203 is covered by the filter 205, the device 100 can obtain dual energy information about the incident radiation 206 by measuring the incident radiation 206 using a type of scintillator 204.

[0064] Since the first pixel subset 202 is not covered by filter 205, the pixel can obtain a total energy (TE) signal. On the other hand, since the second pixel subset 203 is covered by filter 205, the pixel can obtain, for example, a high energy (HE) signal.

[0065] The TE / HE signal can be converted into a low-energy (LE) signal by, for example, processing unit 102 by subtracting the HE signal from the TE signal. The LE and HE signals can then be used in, for example, a dual-energy (DE) imaging algorithm. Alternatively, the dual-energy algorithm can be modified to use both TE and HE signals.

[0066] Figure 3 A schematic diagram of a detector 101 according to another embodiment is shown.

[0067] According to an embodiment, the first pixel subset 202 and the second pixel subset 203 are arranged in an alternating pattern in space.

[0068] For example, in Figure 3In one embodiment, every other pixel is located in the first pixel subset 202, and every other pixel is located in the second pixel subset 203.

[0069] In some embodiments, the plurality of pixels 201 can be arranged in a one-dimensional row. The object to be imaged can then be moved relative to the plurality of pixels 201, for example, by a conveyor belt, to obtain a two-dimensional image of the object. This can be referred to as line scanning and can be used for low-cost imaging schemes.

[0070] In some embodiments, pixels in the first subset 202 and the second subset 203 can be coupled to a single ASIC. Processing unit 102 may include an ASIC. However, the signal level difference between the first subset 202 and the second subset 203 can be significant. Therefore, if only one gain setting can be used in the ASIC, the signal-to-noise ratio cannot be optimized for both subsets. Therefore, in some embodiments, the first pixel subset 202 can be coupled to a first ASIC, and the second pixel subset 203 can be coupled to a second ASIC. This allows for ASIC gain tuning for each energy range. However, this may require a sensor fill factor that is twice as small per pixel, which could reduce the overall signal level.

[0071] Figure 4 The illustration shows a schematic diagram of radiation intensity value estimation according to an embodiment.

[0072] According to an embodiment, the processing unit 102 is also configured to calculate an estimated radiation intensity value by performing the following operations.

[0073] Processing unit 102 can calculate attenuation factor R401 for each pixel pair 301 of a plurality of pixel pairs. Each pixel pair 301 of the plurality of pixel pairs may include one pixel in a first subset 202 and one pixel in a second subset 203.

[0074] The number of pixel pairs 301 for which the processing unit 102 calculates the attenuation factor R 401 can vary. For example, the number of pixel pairs 301 in multiple pixel pairs can be greater than three, such as five, six, seven or nine.

[0075] The attenuation factor R 401 can quantitatively determine how much the radiation intensity in the second pixel subset 203 has attenuated compared to the first pixel subset 202. The attenuation factor R 401 can be calculated, for example, as R = N. HE / N TE , where N TE N is the radiation intensity value obtained by the pixels in the first pixel subset 202 of pixel pair 301. HE It is the obtained radiation intensity value of the pixels in the second pixel subset 203 of pixel pair 301.

[0076] N TE It can also be referred to as the acquired / measured TE count, N HE It can also be referred to as the HE count obtained / measured. In this document, the TE count may refer to the number of events in the first energy range due to incident radiation 206, while the HE count may refer to the number of events in the second energy range due to incident radiation 206.

[0077] Processing unit 102 can use spatial filter 402 and attenuation factor R 401 of multiple pixel pairs 301 to calculate the filtered attenuation factor R. f 403.

[0078] Processing unit 102 can use the obtained radiance value N of at least one pixel in the second pixel subset. HE 404 and the filtered attenuation factor R f 403 is used to calculate the first energy range N TE,e The radiation intensity estimate in 406. For example, processing unit 102 can use N TE,e =N HE / R f To calculate the estimated radiation intensity value of 406.

[0079] According to an embodiment, spatial filter 402 includes a spatial low-pass filter, a moving average filter, a moving median filter, a weighted median filter, or a Gaussian filter. The appropriate type of spatial filter and the parameters associated with it can vary depending on the imaging application.

[0080] The spatial filter 402 can be, for example, one-dimensional or two-dimensional. For example, if the plurality of pixels 201 are arranged in a one-dimensional array in space, then the spatial filter 402 can be one-dimensional. On the other hand, if the plurality of pixels 201 are arranged in a two-dimensional array in space, then the spatial filter 402 can be two-dimensional.

[0081] In calculating the filtered attenuation factor R F At 403, filter 402 can apply weighting. For example, filter 402 can weight the attenuation factor R 401 of pixel 301 more for pixels that are closer to the pixel for which it calculates the radiance estimate 406.

[0082] For example, processing unit 102 can calculate the filtered attenuation factor R by performing a convolution operation between spatial filter 402 and attenuation factor R 401. f 403. Alternatively, for example, in the case of a nonlinear spatial filter, processing unit 102 may perform some other computational operations.

[0083] In other embodiments, processing unit 102 may calculate the radiation intensity estimate in other ways. For example, processing unit 102 may filter the radiation intensity values ​​obtained from the first pixel subset 202 and / or the second pixel subset 203, and calculate a filtered attenuation factor R based on the filtered intensity values. f 403.

[0084] According to an embodiment, the processing unit 102 is further configured to calculate an estimated radiant intensity value for at least one pixel in the first pixel subset 202 within a second energy range using the obtained radiant intensity value of at least one pixel in the first pixel subset 202 and the obtained radiant intensity values ​​of at least two pixels in the second pixel subset. Therefore, the processing unit 102 can, for example, calculate an estimated HE count value for the pixels in the first pixel subset 202. For example, the processing unit 102 can calculate a filtered attenuation factor R as disclosed herein. f Then, the estimated HE count is calculated as N. HE,e =R f ×N TE .

[0085] Figure 5 The figure illustrates a graph representation of the TE and HE counts and the attenuation factor according to an embodiment.

[0086] exist Figure 5 In the embodiment, a measured TE count 501 and an estimated TE count 406, and a measured HE count 404 and an estimated HE count 502 are illustrated. The measured counts are represented by solid circles, and the estimated counts are represented by non-solid circles.

[0087] exist Figure 5 In this embodiment, the attenuation factor 401 is represented by a hollow circle. For each pixel pair, each attenuation factor is calculated as R = N. HE / N TE The filtered attenuation factor R f 403 is represented by a line. The filtered attenuation factor R is calculated using a moving median filter of length 7 and an attenuation factor of 401. f 403.

[0088] The filtered attenuation factor R, as disclosed above, has already been used. f 403 and the measured TE count 501 are used to calculate Figure 5 The estimated HE count 502 is illustrated in the embodiment. Similarly, the filtered attenuation factor R disclosed above has been used. f 403 and the measured HE count 404 are used to calculate the estimated TE count 406.

[0089] Figure 6The figure illustrates a graph representation of the TE and HE counts and the attenuation factor according to another embodiment.

[0090] Figure 6 The curves illustrated in the embodiments represent Figure 5 A portion of the curve illustrated in the embodiment.

[0091] Figure 7 The illustration shows a schematic diagram of the dark-corrected raw data 700 as a grayscale image according to an embodiment. The raw data 700 corresponds to the measured TE and HE counts.

[0092] exist Figure 7 In this embodiment, in the horizontal direction, every other column corresponds to the measured TE count, and every other column corresponds to the measured HE count. Therefore, the horizontal resolution for each energy range is half the total horizontal resolution of the original data 700.

[0093] Figure 8 The illustration shows a schematic diagram of attenuation factor 401 as a grayscale image according to an embodiment.

[0094] exist Figure 8 In the embodiments disclosed herein, Figure 7 In the embodiment, an attenuation factor of 401 was calculated for each horizontal pixel pair.

[0095] Figure 9 The illustration shows a schematic diagram of a filtered attenuation factor 403 as a grayscale image according to an embodiment.

[0096] exist Figure 9 In the embodiments described, filtering has been performed in the horizontal direction by... Figure 8 The attenuation factor of the embodiment is obtained as a filtered attenuation factor 403.

[0097] Figure 10 The illustration shows a schematic diagram of the restored TE output 1000 as a grayscale image according to an embodiment.

[0098] The recovered TE output 1000 can be obtained by using the TE column measured from the original data 700 and by using the HE count measured from the original data 700 and the estimated TE count of the other columns by using the filtered attenuation factor 403 disclosed herein.

[0099] Figure 11 The illustration shows a schematic diagram of the restored HE output as a grayscale image according to an embodiment.

[0100] The recovered HE output 1100 can be obtained by using the HE column measured from the original data 700 and by using the TE count measured from the original data 700 and the estimated HE count of the other columns by using the filtered attenuation factor 403 disclosed herein.

[0101] Figure 12 A flowchart of method 1200 according to an embodiment is illustrated.

[0102] According to an embodiment, a method 1200 for imaging using a detector comprising a plurality of pixels includes obtaining a 1201 signal from each of the plurality of pixels, wherein the plurality of pixels includes a first subset of pixels configured to detect incident x-ray or gamma-ray radiation in a first energy range and a second subset of pixels configured to detect incident x-ray or gamma-ray radiation in a second energy range, wherein the second energy range is a subrange of the first energy range.

[0103] Method 1200 may also include calculating the radiant intensity value of each of the 1202 plurality of pixels based on the signal of each pixel.

[0104] Method 1200 may further include using the obtained radiance values ​​of at least one pixel in the second pixel subset and the obtained radiance values ​​of at least two pixels in the first pixel subset to calculate 1203 an estimated radiance value of at least one pixel in the second pixel subset within a first energy range.

[0105] Method 1200 can be executed by, for example, processing unit 102.

[0106] Any ranges or device values ​​given herein may be extended or modified without loss of the desired effect. Furthermore, unless expressly prohibited, any embodiment may be combined with other embodiments.

[0107] Although the subject matter has been described in language specific to structural features and / or actions, it should be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or actions described above. Rather, the specific features and actions described above are disclosed as examples for implementing the claims, and other equivalent features and actions are intended to fall within the scope of the claims.

[0108] It should be understood that the above benefits and advantages may relate to one embodiment or several embodiments. The embodiments are not limited to embodiments that solve any or all of the described problems or that have any or all of the described benefits and advantages. It should also be understood that a reference to "an" may refer to one or more of these items.

[0109] The steps of the methods described herein can be performed in any suitable order, or simultaneously where appropriate. Furthermore, individual blocks can be removed from any method without departing from the spirit and scope of the subject matter described herein. Aspects of any of the embodiments described above can be combined with aspects of any other described embodiments without loss of the desired effect to form other embodiments.

[0110] As used herein, the term "comprising" means including the identified methods, blocks, or elements, but such blocks or elements are not included in an exclusive list, and methods or apparatus may include additional blocks or elements.

[0111] It should be understood that the above description is given by way of example only, and various modifications can be made by those skilled in the art. The above specification, examples, and data provide a complete description of the structure and use of exemplary embodiments. Although various embodiments have been described above with a degree of specificity or by reference to one or more individual embodiments, those skilled in the art can make various changes to the disclosed embodiments without departing from the spirit or scope of this specification.

Claims

1. An imaging device (100), comprising: The detector (101) includes a plurality of pixels (201), wherein the plurality of pixels includes a first subset of pixels (202) configured to detect incident x-ray or gamma-ray radiation in a first energy range and a second subset of pixels (203) configured to detect incident x-ray or gamma-ray radiation in a second energy range, wherein the second energy range is a subrange of the first energy range; and Processing unit (102), coupled to detector (101) and configured to: A signal is obtained from each of the plurality of pixels; The radiation intensity value (404, 501) of each of the plurality of pixels is obtained based on the signal of each pixel. and The radiation intensity estimate (406) of the at least one pixel in the second pixel subset in the first energy range is calculated using the obtained radiation intensity value (404) of at least one pixel in the second pixel subset and the obtained radiation intensity values ​​(501) of at least two pixels in the first pixel subset. The processing unit (102) is further configured to calculate the radiation intensity estimate by performing the following operations: Calculate the attenuation factor (401) for each pixel pair (301) among the plurality of pixels, wherein each pixel pair among the plurality of pixels includes a pixel in the first pixel subset and a pixel in the second pixel subset; The filtered attenuation factor (403) is calculated using the spatial filter (402) and the attenuation factor (401) of the plurality of pixel pairs. and The estimated value of radiation intensity (406) in the first energy range is calculated using the obtained radiation intensity value (404) of at least one pixel in the second pixel subset and the filtered attenuation factor (403).

2. The device (100) according to claim 1, wherein the spatial filter (402) comprises a spatial low-pass filter, a moving average filter, a moving median filter, a weighted median filter, or a Gaussian filter.

3. The device (100) according to claim 1, wherein the processing unit (102) is further configured to calculate an estimated value (502) of the radiation intensity of the at least one pixel in the first pixel subset (202) in the second energy range using the obtained radiation intensity value (501) of at least one pixel in the first pixel subset and the obtained radiation intensity values ​​of at least two pixels in the second pixel subset.

4. The device (100) according to any one of claims 1 to 3, wherein the detector (101) further comprises a filter (205) arranged to prevent at least a portion of incident x-ray or gamma-ray radiation outside the second energy range from entering the plurality of pixels of the second pixel subset (203).

5. The device (100) of claim 4, wherein the filter (205) further comprises a plurality of apertures arranged to allow the incident x-ray or gamma-ray radiation to enter a plurality of pixels of the first pixel subset (202).

6. The device (100) according to any one of claims 1 to 3, wherein the first subset of pixels and the second subset of pixels are arranged in an alternating pattern in space.

7. A dual-energy X-ray or gamma-ray imaging apparatus, comprising the device (100) according to any one of claims 1 to 6.

8. A method (1200) for imaging using a detector comprising a plurality of pixels, wherein the plurality of pixels includes a first subset of pixels configured to detect incident x-ray or gamma-ray radiation in a first energy range and a second subset of pixels configured to detect incident x-ray or gamma-ray radiation in a second energy range, wherein the second energy range is a subrange of the first energy range, the method comprising: The (1201) signal is obtained from each of the plurality of pixels; (1202) The radiation intensity value of each of the plurality of pixels is obtained based on the signal of each pixel; (1203) Calculate the estimated radiation intensity of the at least one pixel in the second pixel subset within the first energy range using the obtained radiation intensity value of at least one pixel in the second pixel subset and the obtained radiation intensity values ​​of at least two pixels in the first pixel subset; The estimated radiation intensity value calculated in (1203) includes: Calculate the attenuation factor for each pixel pair among the plurality of pixels, wherein each pixel pair among the plurality of pixels includes a pixel in the first pixel subset and a pixel in the second pixel subset; The filtered attenuation factor is calculated using the spatial filter and the attenuation factor of the plurality of pixel pairs; The estimated radiation intensity within the first energy range is calculated using the obtained radiation intensity value of at least one pixel in the second pixel subset and the filtered attenuation factor.

9. The method (1200) according to claim 8, wherein the spatial filter comprises a spatial low-pass filter, a moving average filter, a moving median filter, a weighted median filter, or a Gaussian filter.

10. The method (1200) according to claim 8 or 9, further comprising calculating a radiation intensity estimate of the at least one pixel in the first pixel subset within the second energy range using a calculated intensity value of at least one pixel in the first pixel subset and obtained radiation intensity values ​​of at least two pixels in the second pixel subset.

11. A computer program product comprising program code configured to perform the method according to any one of claims 8 to 10 when the computer program product is executed on a computer.

Images