X-ray detector device, multi-layer surface detector and method

Abstract

The invention relates to an X-ray detector device (1) comprising a multi-layer area detector (2) and a computing unit (9). The multi-layer area detector (2) has several X-ray detector layers (3) stacked along a beam path (4), each X-ray detector layer (3) being configured to detect X-rays incident on a sensor surface (5) of the respective X-ray detector layer (3), the sensor surface (5) being divided into several pixel areas (6) arranged in a regular pixel grid (7). The pixel grids (7) of the respective X-ray detector layers (3) are offset from one another by subpixel distances (12) parallel to the sensor surfaces (5) according to a pixel offset arrangement.

Description

[0001] The invention relates to an X-ray detector device, a multi-layer surface detector and a method for operating an X-ray detector device.

[0002] To acquire two-dimensional X-ray images, X-ray detector devices with area detectors are used. Area detectors have a sensor surface onto which the X-rays impinge. The sensor surface is divided into several pixel areas arranged in a regular pixel grid. At each of the individual pixel areas, the locally incident X-rays are detected, and a pixel value corresponding to the X-rays is output. A two-dimensional X-ray image is generated by a computer from the pixel values ​​of the individual pixel areas. The lateral resolution of the X-ray images depends on the number of pixel areas in the pixel grid of the sensor surface.

[0003] Providing area detectors with a higher resolution involves greater effort and therefore higher costs.

[0004] Multilayer surface detectors are known from the prior art. These comprise several X-ray detector layers stacked along the X-ray beam path. Each of the individual X-ray detector layers comprises a surface detector with a respective sensor surface. The detection of X-rays by sequentially arranged surface detectors is possible due to the low absorption of higher-energy X-rays. Multilayer flat panel detectors and their applications are the subject of ongoing research. Their most compelling features compared to single-layer detectors are inherent spectral resolution, as the deeper detection layers are predominantly reached by higher-energy photons, and generally higher dose efficiency due to the higher cumulative detection sensitivity for high-energy photons.

[0005] However, multi-layer detectors have not yet found routine clinical application. Firstly, the spectral separability of the detection layers is poor compared to other spectral imaging techniques such as kV switching. Secondly, the increased dose efficiency is costly, as the manufacturing costs of the multi-layer detectors increase proportionally per layer.

[0006] Research is underway to achieve subpixel super-resolution by intentionally shifting detector pixels between two images. However, spectral imaging is not yet considered.

[0007] Such a method is disclosed, for example, in the publication by Liu et al. 2022 (Liu, Jiayin, and Jae Ho Kim. “A Novel Sub-Pixel-Shift-Based High-Resolution X-ray Flat Panel Detector.” Coatings 12.7 (2022): 921.).

[0008] However, time intervals between individual images can lead to artifacts in the resulting X-ray image.

[0009] It is an object of the present invention to increase a lateral resolution of multi-layer surface detectors in order to expand their application range and / or to reduce production costs compared to X-ray detectors of the same lateral resolution.

[0010] This object is achieved by the respective subject matter of the independent claims. Advantageous further developments and preferred embodiments are the subject matter of the dependent claims.

[0011] A first aspect of the invention relates to an X-ray detector device comprising a multi-layer surface detector and a computing device.

[0012] The multilayer detector comprises a plurality of X-ray detector layers stacked along a beam path direction. In other words, the X-ray detector layers are aligned parallel to one another, with a stacking direction of the X-ray detector layers being parallel to the beam path direction along which the X-ray radiation is guided through the multilayer detector.

[0013] Each of the X-ray detector layers is configured to detect X-rays incident on a sensor surface of the respective X-ray detector layer. The sensor surface is divided into multiple pixel surfaces. The pixel surfaces are arranged in a regular pixel grid, wherein the pixel grids of the respective X-ray detector layers have an identical pixel pitch. In other words, the sensor surfaces comprise multiple pixel surfaces arranged in the regular pixel grid. It is provided that the pixel grids of all X-ray detector layers of the multi-layer surface detector have the identical pixel pitch or a pixel pitch that varies slightly between X-ray detector layers, preferably by up to a maximum of 5%.A change in the pixel pitch can be provided if the X-ray detector is to be used to detect X-rays whose X-ray beams are not parallel to each other but form a conical X-ray beam. A conical X-ray beam is generated, for example, by a point-shaped or approximately point-shaped X-ray source. Approximately point-shaped X-ray sources are normally used in C-arm X-ray machines. In an advantageous embodiment, a variable pixel pitch for conical X-ray radiation can be adjusted to the aperture angle of the X-ray cone. The pixel pitch is also referred to as pixel pitch.

[0014] The pixel areas are configured to output a pixel value corresponding to the X-ray radiation impinging on the respective pixel area. In other words, each of the pixel areas is configured to detect X-ray radiation impinging on the respective pixel area and output the corresponding pixel value, which depends on the X-ray radiation impinging on the respective pixel area. The pixel value can, for example, describe a radiation intensity of the X-ray radiation impinging on the respective pixel area.

[0015] The computing device is configured to receive the pixel values ​​of the pixel areas of the respective X-ray detector layer and to evaluate them using an image processing method in order to generate a two-dimensional X-ray image from the pixel values ​​according to the pixel grid of the respective X-ray detector layer. In other words, the computing device is intended to determine respective X-ray images from the pixel values ​​of the respective X-ray detector layers. In a simplest embodiment of the image processing method, the image processing method can provide a mapping of the respective pixel values ​​according to the pixel grid of the respective X-ray detector layer. The respective X-ray image thus comprises pixels arranged in a point grid that corresponds to or is identical to the pixel grid.

[0016] It is intended that the pixel grids of the respective X-ray detector layers are offset from one another by subpixel pitches parallel to the sensor surfaces according to a pixel offset arrangement. In other words, the pixel surfaces of different X-ray detector layers are not arranged congruently along the beam path direction, but are offset from one another. The offset of the pixel grids of the X-ray detector layers is predetermined by the pixel offset arrangement. The offset occurs by subpixel pitches. In other words, the pixel grids are offset by subpixel pitches that are smaller than the pixel pitch. In other words, a pixel shift exists between the pixel grids of the X-ray detector layers. In contrast to the prior art, the pixel shift does not depend on a detection time but on the X-ray detector position.

[0017] The computing device is configured to determine a regular subpixel grid based on the pixel grids of the respective X-ray detector layers and the pixel offset arrangement, which divides a resulting X-ray image into several subpixel areas. In other words, the offset pixel grids are combined by the computing device into a subpixel grid. The computing device is configured to determine the respective subpixel values ​​for the respective subpixel areas from the pixel values ​​of the pixel areas using a subpixel determination method.

[0018] The calculation direction is designed to generate the two-dimensional resulting X-ray image from the subpixel values ​​according to the subpixel grid using an overall image processing method.

[0019] The invention offers the advantage that multiple X-ray images of a pixel grid with a lower laterally resolution can be combined to generate an X-ray image with a higher laterally resolution. This makes it possible to provide a lateral resolution in a more cost-effective manner than is possible with a single X-ray device with a higher laterally resolution.

[0020] A further development of the invention provides that the computing device is configured to combine the two-dimensional X-ray images into the resulting X-ray image using a neural network. The combination can be carried out, for example, according to Bhat et al. 2021 (Bhat, Goutam, et al. "Deep reparametrization of multi-frame super-resolution and denoising." Proceedings of the IEEE / CVF International Conference on Computer Vision. 2021).

[0021] A further development of the invention provides that the computing device is configured to combine the two-dimensional X-ray images into the resulting X-ray image using a filtering process. The combination can be carried out, for example, according to Stimpel et al. 2019 (Stimpel, Bernhard, et al. "Multi-modal super-resolution with deep guided filtering." Image processing for medicine 2019: Algorithms-Systems-Applications. Proceedings of the workshop from March 17 to 19, 2019, in Lübeck. Springer Fachmedien Wiesbaden, 2019.).

[0022] A further development of the invention provides that the computing device is configured to combine the two-dimensional X-ray images into the resulting X-ray image using a deconvolution method. Possible deconvolution-based methods are described, for example, in Van Ouwerkerk 2006 (Van Ouwerkerk, JD "Image super-resolution survey." Image and vision Computing 24.10 (2006): 1039-1052).

[0023] A further development of the invention provides that the computing device is configured to combine the two-dimensional X-ray images into the resulting X-ray image using pixel covariance-based methods. Possible pixel covariance-based methods are disclosed, for example, in Van Ouwerkerk 2006 (Van Ouwerkerk, JD "Image super-resolution survey." Image and vision Computing 24.10 (2006): 1039-1052).

[0024] A second aspect of the invention relates to a multilayer surface detector.

[0025] The multi-layer surface detector comprises several X-ray detector layers stacked along a beam path direction.

[0026] Each of the X-ray detector layers is configured to detect X-rays incident on a sensor surface of the respective X-ray detector layer. The sensor surface is divided into several pixel areas. The pixel areas are arranged in a regular pixel grid, wherein the pixel grids of the respective X-ray detector layers have an identical pixel pitch. It is provided that the pixel grids of all X-ray detector layers of the multi-layer surface detector have the identical pixel pitch or a pixel pitch that varies slightly between X-ray detector layers, preferably by up to a maximum of 5%. The pixel areas are configured to output a pixel value corresponding to the X-ray radiation incident on the respective pixel area.

[0027] A third aspect of the invention relates to a method for operating an X-ray detector device. The X-ray detector device comprises a multi-layer surface detector and a computing device. The multi-layer surface detector has a plurality of X-ray detector layers stacked along a beam path direction, wherein each of the X-ray detector layers is configured to detect X-ray radiation incident on a sensor surface of the respective X-ray detector layer. The sensor surface is divided into a plurality of pixel surfaces arranged in a regular pixel grid, wherein the pixel grids of the respective X-ray detector layers have an identical pixel pitch. The pixel grids of the respective X-ray detector layers are offset from one another by subpixel pitches parallel to the sensor surfaces according to a pixel offset arrangement.

[0028] The method provides for pixel values ​​corresponding to the X-rays incident on the respective pixel areas to be output by the pixel areas.

[0029] The computing device receives the pixel values ​​of the pixel areas of the respective X-ray detector layers. Using an image processing method, the computing device generates two-dimensional X-ray images from the pixel values ​​of the respective X-ray detector layers according to the pixel grid of the respective X-ray detector layer.

[0030] Depending on the pixel grids of the respective X-ray detector layers and the pixel offset arrangement, the computing device determines a regular subpixel grid which divides a resulting X-ray image into several subpixel areas.

[0031] The computing device uses a subpixel determination process to determine the respective subpixel values ​​for the respective subpixel areas from the pixel values.

[0032] The computing device uses an image processing method to generate the two-dimensional resulting X-ray image from the subpixel values ​​according to the subpixel grid.

[0033] For use cases or application situations that may arise during the method and which are not explicitly described here, it may be provided that, in accordance with the method, an error message and / or a request to enter user feedback is issued and / or a default setting and / or a predetermined initial state is set.

[0034] The advantages and further developments presented above in connection with the X-ray detector device according to the first aspect of the invention also apply mutatis mutandis to the method according to the invention. Accordingly, the features presented for the X-ray detector device are to be regarded as method features of the method.

[0035] The computing device can, in particular, contain one or more computers, one or more microcontrollers, and / or one or more integrated circuits, for example, one or more application-specific integrated circuits (ASICs), one or more field-programmable gate arrays (FPGAs), and / or one or more single-chip systems (SoCs). The computing unit can also contain one or more processors, for example, one or more microprocessors, one or more central processing units (CPUs), one or more graphics processing units (GPUs), and / or one or more signal processors, in particular one or more digital signal processors (DSPs). The computing unit can also include a physical or virtual network of computers or other of the aforementioned units. In various embodiments, the computing unit includes one or more hardware and / or software interfaces and / or one or more memory units.

[0036] A memory unit can be a volatile data memory, for example a dynamic random access memory (DRAM) or a static random access memory (SRAM), or a non-volatile data memory, for example a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), a flash memory or flash EEPROM, a ferroelectric random access memory (FRAM), a magnetoresistive random access memory,MRAM (magnetoresistive random access memory) or phase-change random access memory (PCRAM).

[0037] Regardless of the grammatical gender of a particular term, persons with male, female or other gender identities are included.

[0038] Further features of the invention emerge from the claims, the figures and the description of the figures. The features and combinations of features mentioned above in the description as well as the features and combinations of features mentioned below in the description of the figures and / or shown in the figures can be encompassed by the invention not only in the respectively specified combination, but also in other combinations. In particular, the invention can also encompass embodiments and combinations of features that do not have all the features of an originally formulated claim. Furthermore, the invention can encompass embodiments and combinations of features that go beyond the combinations of features set out in the backreferences to the claims or deviate from them.

[0039] The invention is explained in more detail below using specific embodiments and associated schematic drawings. In the figures, identical or functionally equivalent elements may be provided with the same reference numerals. The description of identical or functionally equivalent elements may not necessarily be repeated for different figures.

[0040] The figures show: Fig. 1 is a schematic representation of an X-ray detector device according to the prior art; Fig. 2 is a schematic representation of an X-ray detector device; and Fig. 3 a schematic representation of a sequence of a method for operating an X-ray detector device.

[0041] Fig. 1 shows a schematic representation of an X-ray detector device according to the prior art.

[0042] The prior art X-ray detector device 1 shown can have a multi-layer surface detector 2, which can be configured as a two-layer surface detector. The multi-layer surface detector 2 can have two X-ray detector layers 3. The two-layer surface detector is shown in perspective to illustrate both X-ray detector layers 3. The X-ray detector layers 3 can be arranged stacked one behind the other along a beam path direction 4. The respective X-ray detector layers 3 can have sensor surfaces 5, which can be divided into pixel grids 7 by pixel surfaces 6. The pixel grids 7 can have an identical pixel pitch 8. Consecutive pixel surfaces 6 of different X-ray detector layers 3 can be congruent.A computing device 9 can be configured to receive pixel values ​​10 of the pixel areas 6 and to generate a two-dimensional X-ray image 11 from the pixel values ​​10 according to the pixel grid 7 of the sensor areas 5.

[0043] Fig. Figure 2 shows a schematic representation of an X-ray detector device.

[0044] The X-ray detector device 1 can have a multi-layer surface detector 2 and a computing device 9. The multi-layer surface detector 2 can also be designed as a two-layer surface detector. The multi-layer surface detector 2 can have two X-ray detector layers 3, which can be arranged one behind the other along the beam path direction 4. In each of the X-ray detector layers 3, a sensor surface 5 can be arranged, which can be divided into pixel grids 7 by pixel areas 6. The pixel pitches 8 of the pixel grids 7 of the two X-ray detector layers 3 can be identical or differ slightly between the two X-ray detector layers 3, preferably by up to a maximum of 5%. The pixel grids 7 of the two X-ray detector layers 3 can be offset from one another according to a pixel offset arrangement. The two pixel grids 7 can be offset from one another by a subpixel pitch 12.The pixel offset arrangement can specify that the pixel grid 7 of a rear one of the X-ray detector layers 3 is shifted relative to the pixel grid 7 of a front one of the X-ray detector layers 3 by half the pixel pitch 8 in a row direction of the pixel grid 7 and by half the pixel pitch 8 in a column direction of the pixel grid 7. This allows the pixel areas 6 of the two X-ray detector layers 3 to partially overlap. For example, a respective one of the pixel areas 6 of the front X-ray detector layer 3 can overlap with four of the pixel areas 6 of the rear X-ray detector layer 3. The overlap can form partial areas 13. In order for each of the pixel areas 6 of the front X-ray detector layer 3 to overlap with four pixel areas 6 of the rear X-ray detector layer 3, an extension of the pixel grid 7 of the rear X-ray detector layer 3 by one additional row and one additional column can be provided. By superimposing the two offset pixel grids 7, a subpixel grid 14 can be formed, which can be a regular arrangement of subpixel areas 15, which can be formed by the overlapping partial areas 13. The computing device 9 can be configured to receive the pixel values ​​10 of the pixel areas 6 and combine them into a combined X-ray image 16, which can have the subpixel grid 14. The pixel values ​​10 can be calculated into subpixel values ​​17. This makes it possible to provide the combined X-ray image 16, which has the subpixel grid 14, which has a higher resolution than the pixel grid 7 of the individual X-ray detector layer 3.

[0045] The calculation of the pixel values ​​10 to subpixel values ​​17 can be carried out by the computing device 9 according to different methods.

[0046] The basic idea is to shift the pixel grid 7 of the rear X-ray detector layer 3 by the subpixel pitch 12 relative to the pixel grid 7 of the front X-ray detector layer 3, which is half the pixel pitch 8 in the row and column directions. The pixel grid 7 of the rear X-ray detector layer 3 is also supplemented by an additional row and an additional column. As a result, each of the pixel areas 6 of the front X-ray detector layer 3 overlaps with four pixel areas of the rear X-ray detector layer 3. Thus, four subpixel areas 15 per pixel area 6 can be determined using digital signal processing methods, quadrupling the native image resolution.

[0047] Qualified approaches for performing super-resolution can be AI-based. CNN-based methods, when combined with denoising, have been shown to yield robust super-resolution images from multiple images. Filter-based methods, such as fast guided filters—trainable guided filters—have been shown to yield super-resolution images from multi-model images and can also be used for multi-energy images. The approach can include deconvolution-based methods and / or pixel covariance-based methods.

[0048] An artificial neural network may be trained to enable combined super-resolution, noise reduction, and material decomposition for real-time imaging in a single pass

[0049] Overall, the X-ray detector device 1 makes it possible to increase the resolution compared to X-ray detector devices 1 according to the prior art and / or to provide the same resolution as in X-ray detector devices 1 according to the prior art in a more favorable manner.

[0050] The X-ray detector device 1 has a higher readout speed / frame rate compared to conventional two-layer detectors by binning individual layers while maintaining spatial resolution. The X-ray detector device 1 enables a reduction in manufacturing costs because the same resolution can be achieved with two lower-resolution detectors.

[0051] Fig. 3 shows a schematic representation of a sequence of a method for operating an X-ray detector device.

[0052] The method can be operated by an X-ray detector device 1, which in Fig.2 is shown.

[0053] The method can be performed to acquire a resulting X-ray image 16 of an object. For this purpose, the object arranged between an X-ray source and the X-ray detector device 1 can be irradiated with X-ray radiation along a beam path direction 4.

[0054] In a step S1 of the method, the X-ray radiation can be detected by the pixel areas 6 of the X-ray detector layers 3. The pixel areas 6 can provide respective pixel values ​​10, which can describe radiation intensities detected by the respective pixel areas 6.

[0055] In a step S2 of the method, the computing device 9 can receive the pixel values ​​10 of the pixel areas 6. From the pixel values ​​10 of the pixel areas 6 of the X-ray detector layers 3, the respective two-dimensional X-ray images 11 can be generated according to the pixel grid 7 of the respective X-ray detector layer 3 using an image processing method. The two-dimensional X-ray images 11 can have the pixel grid 7.

[0056] In a step S3 of the method, the computing device 9 can determine the regular subpixel grid 14 depending on the pixel grids 7 of the respective X-ray detector layers 3 and the pixel offset arrangement. The subpixel grid 14 can subdivide the resulting X-ray image 16 into several subpixel areas 15.

[0057] In a step S4 of the method, the computing device 9 can determine respective subpixel values ​​17 for the respective subpixel areas 15 from the pixel values ​​10 in a subpixel determination method.

[0058] In a step S5 of the method, the two-dimensional resulting X-ray image 16 can be generated from the subpixel values ​​17 according to the subpixel grid 14 by the computing device 9 using an image processing method.

[0059] In a step S6 of the method, the computing device 9 can output output data 18, which can include the two-dimensional resulting X-ray image 16. QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited non-patent literature

[0000] Liu, Jiayin, and Jae Ho Kim. “A Novel Sub-Pixel-Shift-Based High-Resolution X-ray Flat Panel Detector.” Coatings 12.7 (2022): 921

[0007] Bhat, Goutam, et al. “Deep reparametrization of multi-frame super-resolution and denoising.” Proceedings of the IEEE / CVF International Conference on Computer Vision. 2021

[0020] Stimpel, Bernhard, et al. "Multi-modal super-resolution with deep guided filtering." Image Processing for Medicine 2019: Algorithms-Systems-Applications. Proceedings of the workshop from March 17 to 19, 2019, in Lübeck. Springer Fachmedien Wiesbaden, 2019

[0021] Van Ouwerkerk, JD „Image super-resolution survey.“ Image and vision Computing 24.10 (2006): 1039-1052 [0022, 0023]

Claims

[1] X-ray detector device (1) comprising a multi-layer surface detector (2) and a computing device (9), wherein - the multi-layer surface detector (2) has a plurality of X-ray detector layers (3) stacked along a beam path direction (4), wherein each of the X-ray detector layers (3) is configured to detect X-ray radiation incident on a sensor surface (5) of the respective X-ray detector layer (3), wherein the sensor surface (5) is divided into a plurality of pixel surfaces (6) arranged in a regular pixel grid (7), wherein the pixel grids (7) of the respective X-ray detector layers (3) have an identical pixel pitch (8); wherein the pixel grids (7) of different X-ray detector layers (3) have an identical pixel pitch (8) or a pixel pitch (8) that varies slightly, preferably by up to 5%, between the different X-ray detector layers (3), - the pixel areas (6) are configured to output a respective pixel value corresponding to the X-ray radiation incident on the respective pixel area (6); - the computing device (9) is configured to receive the pixel values ​​(10) of the pixel areas (6) of the respective X-ray detector layer (3) and, according to an image processing method, to generate a two-dimensional X-ray image (11) from the pixel values ​​(10) in accordance with the pixel grid (7) of the respective X-ray detector layer (3); characterized by , that - the pixel grids (7) of the respective X-ray detector layers (3) are offset from one another by subpixel spacings (12) parallel to the sensor surfaces (5) according to a pixel offset arrangement, - the computing device (9) is designed to determine a regular subpixel grid (14) depending on the pixel grids (7) of the respective X-ray detector layers (3) and the pixel offset arrangement, which subdivides a resulting X-ray image (16) into a plurality of subpixel areas (15), - the computing device (9) is designed to determine respective subpixel values ​​(17) for the respective subpixel areas (15) from the pixel values ​​(10) in a subpixel determination method, - the computing device (9) is configured to generate the two-dimensional resulting X-ray image (16) from the subpixel values ​​(17) according to the subpixel grid (14) using an image processing method. [2] X-ray detector device (1) according to claim 1, characterized bythat the computing device (9) is designed to combine the two-dimensional X-ray images (11) by means of a neural network to form the resulting X-ray image (16). [3] X-ray detector device (1) according to claim 1 or 2, characterized by that the computing device (9) is designed to combine the two-dimensional X-ray images (11) by means of a filtering process to form the resulting X-ray image (16). [4] X-ray detector device (1) according to one of the preceding claims, characterized by that the computing device (9) is designed to combine the two-dimensional X-ray images (11) into the resulting X-ray image (16) by means of a deconvolution process. [5] X-ray detector device (1) according to one of the preceding claims, characterized bythat the computing device (9) is configured to combine the two-dimensional X-ray images (11) into the resulting X-ray image (16) by means of a pixel covariance-based method. [6] Multilayer surface detector (2), where - the multi-layer surface detector (2) has a plurality of X-ray detector layers (3) stacked along a beam path direction (4), wherein each of the X-ray detector layers (3) is configured to detect X-ray radiation incident on a sensor surface (5) of the respective X-ray detector layer (3), wherein the sensor surface (5) is divided into a plurality of pixel surfaces (6) arranged in a regular pixel grid (7), wherein the pixel grids (7) of the respective X-ray detector layers (3) have an identical pixel pitch (8), wherein the pixel grids (7) of different X-ray detector layers (3) have an identical pixel pitch (8) or a pixel pitch (8) that varies slightly, preferably by up to 5%, between the different X-ray detector layers (3); and - the pixel areas (6) are configured to output a respective pixel value corresponding to the X-ray radiation incident on the respective pixel area (6); characterized by , that - the pixel grids (7) of the respective X-ray detector layers (3) are offset from one another by subpixel distances (12) parallel to the sensor surfaces (5) according to a pixel offset arrangement. [7] A method for operating an X-ray detector device (1) comprising a multi-layer surface detector (2) and a computing device (9), wherein the multi-layer surface detector (2) has a plurality of X-ray detector layers (3) stacked along a beam path direction (4), wherein each of the X-ray detector layers (3) is configured to detect X-ray radiation incident on a sensor surface (5) of the respective X-ray detector layer (3), wherein the sensor surface (5) is divided into a plurality of pixel surfaces (6) arranged in a regular pixel grid (7), wherein the pixel grids (7) of the respective X-ray detector layers (3) have an identical pixel pitch (8), wherein the pixel grids (7) of different X-ray detector layers (3) have an identical pixel pitch (8) or a pixel pitch (8) that varies slightly, preferably by up to 5%, between the different X-ray detector layers (3),wherein the pixel grids (7) of the respective X-ray detector layers (3) are offset from one another parallel to the sensor surfaces (5) by subpixel distances (12) according to a pixel offset arrangement, wherein, - through the pixel areas (6) respective pixel values ​​(10) corresponding to the X-ray radiation incident on the respective pixel area (6) are output; - the computing device (9) receives the pixel values ​​(10) of the pixel areas (6) of the respective X-ray detector position (3) and, according to an image processing method, generates a two-dimensional X-ray image (11) from the pixel values ​​(10) in accordance with the pixel grid (7) of the respective X-ray detector position (3); - a regular subpixel grid (14) is determined by the computing device (9) as a function of the pixel grids (7) of the respective X-ray detector layers (3) and the pixel offset arrangement, which subdivides a resulting X-ray image (16) into a plurality of subpixel areas (15), - the computing device (9) determines the respective subpixel values ​​(17) for the respective subpixel areas (15) from the pixel values ​​(10) in a subpixel determination process, - the two-dimensional resulting X-ray image (16) is generated from the subpixel values ​​(17) according to the subpixel grid (14) by the computing device (9) according to an image processing method.

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