Positioning the object relative to the X-ray detector

Abstract

X-ray imaging system 100 includes an X-ray source 110, an X-ray detector 120, a depth camera 130, and a processor 140. Processor 140 receives depth camera image data from the depth camera, projects the depth camera image data from the perspective of X-ray source 110 onto a radiation receiving surface of X-ray detector 120, and generates an image representation 170 of the depth camera image data projected onto the radiation receiving surface of X-ray detector 120 from the perspective of depth camera 130.

Description

[Technical field]

[0001] The present disclosure relates to positioning an object relative to an X-ray detector. An X-ray imaging system, a computer implemented method, and a computer program product are also disclosed. [Background technology]

[0002] An X-ray imaging system includes an X-ray source and an X-ray detector. The X-ray source and the X-ray detector are separated by an examination region. An object is placed in the examination region in order to perform an X-ray imaging operation on the object. It is important that the object to be imaged is correctly positioned relative to the X-ray detector to avoid the need for repeated X-ray images and the associated X-ray dose increase.

[0003] More specifically, x-ray detectors contain radiation sensitive areas that are used to generate x-ray image data, and it is important that the object is correctly positioned relative to these radiation sensitive areas in order to generate an x-ray image of the object.

[0004] Some x-ray detectors further include dosimetry areas that are used to generate dose data during x-ray image data generation. The dose data may also be used to automatically control the duration of the emission of x-ray radiation, thereby resulting in a desired signal-to-noise ratio in the resulting x-ray image. This operation is sometimes referred to as automatic exposure control "AEC". Correct positioning of the patient relative to these dosimetry areas is also important, especially when performing x-ray imaging procedures on objects that contain density variations.

[0005] As an example, when performing an external chest imaging operation, it is important to first position the patient's chest cavity so that it overlaps the radiation sensitive area of ​​the X-ray detector, and then position the radiation dosimetry area of ​​the X-ray detector behind the spine with little or no overlap with the spine. If the spine obscures the radiation dosimetry area, the X-ray attenuation by the dense spine will suppress the measured dose data. If the dose data is used to automatically control the duration of the emission of X-ray radiation by an automatic exposure control, the resulting extension of this duration may deteriorate the contrast of the X-ray image, making it inaccurate for diagnostic purposes.

[0006] Positioning of an object relative to an X-ray detector is traditionally performed by eye or via a monitor that displays a visible or red-green-blue (RGB) camera image of the object. A depth image generated by a depth camera is likewise displayed on a monitor and is likewise used to position the object relative to the X-ray detector. The radiation sensitive area of ​​the X-ray detector and the extent of its dosimetry area are typically marked on the radiation receiving surface of the detector. In use, an operator uses the markings on the surface of the detector to position the object relative to the detector by eye or via the monitor. Summary of the Invention [Problem to be solved by the invention]

[0007] However, conventional approaches for positioning an object relative to an X-ray detector have drawbacks. To avoid obscuring the path between the X-ray source and the X-ray detector, the camera, and also the human eye, typically views the inspection area between the X-ray source and the X-ray detector from a position that is offset relative to the X-ray source. With a depth camera at such an offset position, it is difficult for an operator to ascertain whether the X-ray radiation emitted by the X-ray source creates the desired projection image of the object on the X-ray detector, especially when the offset is large. Moreover, the object may obscure markings on the radiation receiving surface of the detector. Such problems may result in the object being suboptimally positioned relative to the detector, creating the need to retake the X-ray image. This disrupts the workflow and increases the radiation dose to the object.

[0008] Therefore, there is a need to improve the way an object is positioned relative to an X-ray detector. [Means for solving the problem]

[0009] According to one aspect of the present disclosure, an X-ray imaging system is provided. The X-ray imaging system includes an X-ray source, an X-ray detector, a depth camera, and a processor. The X-ray source and the X-ray detector are separated by an inspection area for performing an X-ray imaging operation on an object when the object is received within the inspection area. The depth camera is configured to view the inspection area to generate depth camera image data representative of the object when the object is received within the inspection area. The processor is configured to: Receiving depth camera image data; projecting the depth camera image data onto a radiation receiving surface of an x-ray detector from a perspective of the x-ray source; generating an image representation of the depth camera image data projected onto a radiation receiving surface of the X-ray detector from a viewpoint of the depth camera; The present invention is configured to perform the following steps.

[0010] Further aspects, features, and advantages of the present disclosure will become apparent from the following description of examples which proceeds with reference to the accompanying drawings. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic diagram illustrating a first view of an example X-ray imaging system 100 including an X-ray source and an X-ray detector 120, in accordance with some embodiments of the present disclosure. [Diagram 2] 1 is a schematic diagram illustrating a second view of an example X-ray imaging system 100 including an X-ray source and an X-ray detector 120, in accordance with some embodiments of the present disclosure. [Diagram 3] 1 is a schematic diagram illustrating a comparative example of an arrangement including an X-ray source, an X-ray detector 120, and a depth camera 130. [Figure 4] 1 is a schematic diagram illustrating an example arrangement including an X-ray source, an X-ray detector 120, a depth camera 130, and a processor 140, according to some embodiments of the present disclosure. [Diagram 5] A schematic diagram illustrating a first example of an image representation 170 of depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130, in accordance with some embodiments of the present disclosure. [Figure 6] A schematic diagram illustrating a second example of an image representation 170 of depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130, in accordance with some embodiments of the present disclosure. [Figure 7] A schematic diagram illustrating a third example of an image representation 170 of depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130, in accordance with some aspects of the present disclosure. [Figure 8] A schematic diagram illustrating a fourth example of an image representation 170 of depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130, in accordance with some embodiments of the present disclosure. [Figure 9] A schematic diagram illustrating a fifth example of an image representation 170 of depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130, in accordance with some embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Examples of the present disclosure are provided with reference to the following description and figures. In this description, for purposes of explanation, numerous specific details of a particular example are described. Reference herein to an "example," "implementation," or similar words means that a feature, structure, or characteristic described with an example is included in at least that one example. It should also be recognized that features described in connection with one example may also be used in other examples, and that for brevity, not all features are necessarily repeated in each example. For example, features described in connection with an X-ray imaging system may be implemented in a corresponding manner in a computer-implemented method and in a computer program product.

[0013] In the following description, reference is made to an X-ray imaging system, such as a DigitalDiagnost C90 commercially available from Philips Healthcare of Best, The Netherlands, or another type of X-ray imaging system. In some example arrangements, the X-ray source of the X-ray imaging system is mounted to the ceiling via a gantry, and the corresponding X-ray detector is mounted to a stand and held in a vertical position. However, it should be recognized that examples of the present disclosure are not limited to this particular arrangement, and the X-ray source and X-ray detector may alternatively be mounted in a different manner and held in a different position.

[0014] In the following description, reference is made to various methods implemented by a processor, i.e., a computer. It is noted that the computer-implemented methods disclosed herein are provided as a non-transitory computer-readable storage medium including stored computer-readable instructions that, when executed by at least one processor, cause the at least one processor to implement the method. In other words, the computer-implemented methods are implemented in a computer program product. The computer program product can be provided by dedicated hardware or by hardware capable of executing software together with appropriate software. When provided by a processor, the functionality of the features of the method can be provided by a single dedicated processor, or by a single shared processor, or by multiple individual processors, some of which may be shared. The explicit use of the terms "processor" or "controller" should not be construed as an exclusive reference to hardware capable of executing software, but can implicitly include, but is not limited to, digital signal processor "DSP" hardware, read-only memory "ROM" for storing software, random access memory "RAM", non-volatile storage devices, and the like. Additionally, examples of the disclosure may be in the form of a computer usable storage medium or computer program product accessible from a computer readable storage medium, the computer program product providing program code for use by or in connection with a computer or any instruction execution system. For purposes of this description, a computer usable storage medium or computer readable storage medium may be any apparatus capable of containing, storing, communicating, propagating, or transporting a program for use by or in connection with an instruction execution system, apparatus, or device. The medium may be an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system or device or propagation medium.Examples of computer-readable media include semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory "RAM", a read-only memory "ROM", a rigid magnetic disk, and an optical disk. Current examples of optical disks include Compact Disk-Read Only Memory "CD-ROM", Compact Disk-Read / Write "CD-R / W", Blu-Ray™, and DVD.

[0015] As mentioned above, it is important that the object to be imaged is correctly positioned relative to the x-ray detector to avoid the need for repeated x-ray images and the associated increased x-ray dose.

[0016] FIG. 1 is a schematic diagram illustrating a first perspective of an example X-ray imaging system 100 including an X-ray source and an X-ray detector 120, according to some embodiments of the present disclosure. The X-ray imaging system 100 further includes a depth camera 130 and a processor 140. The X-ray source 110 and the X-ray detector 120 are separated by an inspection region 150 for performing an X-ray imaging operation on an object 160 when the object is received within the inspection region. The X-ray source and the X-ray detector are typically maintained in a stationary position during the imaging operation. The object is, for example, a part of a human body, or in fact any object. In the illustrated example, the X-ray source is mounted to the ceiling via a gantry, and the X-ray detector is mounted to a stand and held in a vertical position. Alternative arrangements, mounting arrangements, and positions of the X-ray source 110 and the X-ray detector 120 may also be used.

[0017] FIG. 2 is a schematic diagram illustrating a second perspective of an example X-ray imaging system 100 including an X-ray source and an X-ray detector 120 according to some aspects of the present disclosure. Compared to FIG. 1, the perspective of FIG. 2 more clearly illustrates the position of the X-ray source 110 and the depth camera 130. Also in FIG. 2, an example object 160 in the form of a patient is received in an examination area 150 to perform an X-ray imaging operation on the patient, which in the illustrated case is a chest X-ray imaging operation. The solid line extending between the X-ray source 110 and the X-ray detector 120 in FIG. 1 and FIG. 2 indicates the volumetric range of overlap between the X-ray beam emitted by the X-ray source 110 and the X-ray radiation sensitive area of ​​the X-ray detector 120, within which the X-ray image data is generated. This volumetric range of overlap defines the examination area 150. The perimeter of the X-ray radiation sensitive area 180 of the X-ray detector is marked on the radiation receiving surface of the X-ray detector, as illustrated by a rectangular outline on the X-ray detector in Figure 1. In some examples, the X-ray detector 120 further includes one or more radiation dosimetry areas 190 for generating X-ray dosimetry data. These are sometimes referred to as automatic exposure control "AEC" chambers. In the illustrated example of Figure 1, there are five circular radiation dosimetry areas, but in other examples these may have different shapes and there may be a different number of radiation dosimetry areas, or in some cases there may be none at all.

[0018] During use, in order to obtain a reliable X-ray image of the object 160, it is desirable for the object 160 to be correctly positioned relative to the X-ray detector 120, or more specifically, relative to the X-ray radiation sensitive area 180 and / or one or more radiation dosimetry areas 190.

[0019] The depth camera 130 illustrated in Figures 1 and 2 is configured to view the inspection area 150 to generate depth camera image data that represents the object 160 when the object is received within the inspection area 150. In other words, the depth camera 130 has a field of view that overlaps with a portion of the inspection area 150. In general, the depth camera image data generated by the depth camera represents the distance between the depth camera and a point on the surface of the object within the field of view of the depth camera. With reference to Figures 1 and 2, the depth camera image data therefore represents the three-dimensional shape of the surface of the object 160. In the example arrangement illustrated in Figures 1 and 2, the minimum range of the field of view of the depth camera is indicated by a dashed line extending between the depth camera 130 and the X-ray detector 120.

[0020] The depth camera 130 in the example arrangements illustrated in Figures 1 and 2 is mechanically coupled to the X-ray source 110. However, the depth camera 130 may alternatively be positioned elsewhere to view the inspection area 150. The depth camera may, for example, be mechanically coupled to a wall or to the ceiling of the room in which the X-ray imaging system 100 is located, or to a stand that is placed on the floor of the room. The depth camera may alternatively be mobile. In some examples, the depth camera may thus be capable of being moved around the room in which the X-ray imaging system 100 is located. In each of these alternative arrangements, the depth camera may be able to view the inspection area 150.

[0021] Various types of depth cameras are envisaged for use as the depth camera 130. The camera employs, for example, time-of-flight, or LIDAR principles, or structured light principles, or binocular stereoscopic principles. In the time-of-flight, or LIDAR principles, the time it takes for an emitted light pulse to travel from the camera's position to an object in the scene and back again is used to generate depth camera image data representing the distance to the object. The Azure Kinect DK depth camera and the Intel RealSense™ LiDAR camera L515 are examples of depth cameras employing this principle. In the structured light principle, an optical pattern is projected onto the surface of an object in the scene, and the difference between the original projected pattern and the pattern distorted by the object's surface is imaged by one or more cameras. In the binocular stereoscopic principle, different views of the scene are used to compute a depth map of the scene.

[0022] In some examples, the depth camera 130 also generates optical image data representative of the object 160 when the object is received within the inspection region 150. This optical image data may be provided by the aforementioned cameras in addition to the depth camera image data provided by the aforementioned cameras. Such cameras are referred to as RGB-D cameras. The optical image data represents the visible or infrared portions of the light spectrum.

[0023] The processor 140 illustrated in FIG. 1 is configured to receive depth camera image data. The processor receives the depth camera image data via any form of digital communication. The processor 140 receives the depth camera image data from the depth camera 130. The communication path may be direct or indirect. The processor 140 and the depth camera 130 include a direct wired or wireless communication path, such as an electrical cable or Ethernet, or a wireless infrared or RF communication path, such as Bluetooth, as illustrated by the arrows connecting these items in FIG. 1 and FIG. 2. Alternatively, the communication path may be indirect, and the processor 140 and the depth camera 130 may be in communication with each other via the Internet, the cloud, or a computer-readable storage memory.

[0024] Additionally, the processor 140 projecting the depth camera image data onto a radiation receiving surface of an x-ray detector 120 from a perspective of an x-ray source 110; generating an image representation 170 of the depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130; The present invention is configured to perform the following steps.

[0025] In doing so, an image representation 170 is provided that obviates one or more of the challenges associated with positioning an object relative to an x-ray source, which will be described with reference to Figures 3 and 4.

[0026] 3 is a schematic diagram illustrating a comparative example of an arrangement including an X-ray source, an X-ray detector 120, and a depth camera 130. In FIG. 3, the X-ray source and the X-ray detector are separated by an inspection region 150. The X-ray source and the X-ray detector are used to perform an X-ray imaging operation on an object 160 placed in the inspection region 150. The X-ray source 110 is focused into a solid angle Ω x 3 generates X-ray radiation in a volumetric beam defined by x-ray source 110 and the center of the X-ray detector, which is detected by the X-ray detector 120 to generate X-ray image data. At an offset position with respect to axis 200 passing through the X-ray source 110 and the center of the X-ray detector is a depth camera 130, or alternatively an optical camera. The depth camera 130 is positioned to view the inspection area 150 and also the object 160. The depth camera image, or indeed the optical camera image, generated from this offset position somewhat assists the operator to position the object 160 relative to the detector 120 to generate an X-ray image of the object 160. However, with the depth camera at this offset position, it is difficult for the operator to be sure whether the X-ray radiation emitted by the X-ray source creates the desired projection image of the object 160 on the X-ray detector 120, especially when the offset is large. The arrangement of FIG. 3 thus results in the object 160 being mispositioned relative to the X-ray detector, necessitating retaking the X-ray image with the object 160 in a better position.

[0027] To address this issue, one prior art approach has proposed to distort the depth camera image data and view it from the perspective of the X-ray source. However, this approach produces an intuitive view of the object 160. Moreover, this approach suffers from the drawback that the depth camera image data is lost in occluded regions of the detector surface. With reference to the arrangement illustrated in FIG. 3, the solid angle Ω c , and the dashed lines extending from the depth camera 130 define the extent of the boundary of the object 160 on the surface of the X-ray detector as seen from the perspective of the depth camera. The solid lines extending from the X-ray source indicate the extent of the boundary of the object 160 on the surface of the detector 120 as viewed from the perspective of the X-ray source 110. When viewed from this perspective, the depth camera image data is absent from the shaded occlusion regions in FIG. 3. To compensate for the absence of depth camera image data in the occlusion regions, the occlusion regions are repaired with data acquired in the absence of the object 160. This adds further complexity to the approach relative to viewing the depth camera image data from the perspective of the X-ray source.

[0028] FIG. 4 is a schematic diagram illustrating an example arrangement including an X-ray source, an X-ray detector 120, a depth camera 130, and a processor 140 according to some aspects of the present disclosure. As in the comparative example of FIG. 3, in FIG. 4 the depth camera 130 is positioned to view an inspection area 150. In contrast to the comparative example described with reference to FIG. 3, in the approach of the present disclosure, the depth camera image data is projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the X-ray source 110. An image representation 170 of the depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130 is then generated. The projection is performed mathematically based on the relative positions of the X-ray source 110, the X-ray detector 120, and the depth camera 130. With reference to FIG. 4, this is illustrated as a portion of the surface 210 of the object 160, which is seen by the depth camera 130 and projected onto the radiation receiving surface of the X-ray detector 120 to provide projected image data 220. An image representation of this projected image data 220 is then generated from the perspective of the depth camera 130. This image representation is more intuitive than a view of the depth camera image data from the perspective of the x-ray source. Thus, the use of this image representation reduces the chance that the object 160 is mispositioned relative to the x-ray detector 120, reducing the need to retake x-ray images. Moreover, because the image representation is provided from the perspective of the depth camera, it does not need to be restored by having the same perspective from which the depth camera image data was acquired.

[0029] The projection of the depth camera image data onto the radiation receiving surface of the X-ray detector 120, and the generation of the image representation 170 of the projected depth camera image data, is typically performed based on a predetermined spatial relationship between the X-ray source 110, the X-ray detector 120, and the depth camera 130. The predetermined spatial relationship is used to calculate a spatial transformation that is applied to the relevant data to perform the projection.

[0030] The predetermined spatial relationship between the X-ray source 110, the X-ray detector 120, and the depth camera 130 may be determined in different manners.

[0031] In some examples, the positions of one or more of the X-ray source 110, the X-ray detector 120, and the depth camera 130 are fixed positions, and the predetermined spatial relationship is determined using calibration data that represents the fixed positions. In some examples, the positions of all three of the X-ray source 110, the X-ray detector 120, and the depth camera 130 are fixed. In these examples, the predetermined spatial relationship between the X-ray source 110, the X-ray detector 120, and the depth camera 130 is determined based on calibration data that represents the relative positions of the X-ray source 110, the X-ray detector 120, and the depth camera 130.

[0032] The positions of the X-ray source 110, the X-ray detector 120, and the depth camera 130 are fixed, for example by mechanically mounting the relevant items to a reference position such as a wall, ceiling, floor, etc. In some examples, it is envisioned that one or more of these items can be positioned in one of a number of selectable fixed positions and provide calibration data representative of each of the fixed positions. For example, the X-ray source 110 and / or the X-ray detector 120 are moved to one of a number of selectable fixed positions. The calibration data representative of the positions or relative positions are stored in a database, for example as a look-up table, and accessed by a processor to calculate the aforementioned spatial transformation.

[0033] In some examples, the position of one or more of the X-ray source 110, the X-ray detector 120, and the depth camera 130 can be moved to any position, and a predetermined spatial relationship between the X-ray source 110, the X-ray detector 120, and the depth camera 130 is determined using a position sensor. In this regard, various types of position sensors are contemplated, including position sensors employing optical radio frequency "RF" or ultrasonic tracking techniques. Examples of suitable position sensors include laser-based optical range finders, RF and ultrasonic ranging transponders, and optical cameras configured to track the position of fiducial markers disposed on one or more of the X-ray source 110, the X-ray detector 120, and the depth camera 130. In one example, an additional depth camera is used to track the position of one or more of the X-ray source 110, the X-ray detector 120, and the depth camera 130.

[0034] In one example, the spatial relationship between the depth camera 130 and the X-ray detector 120 is determined from depth camera image data generated by the depth camera 130. In this example, the depth camera 130 is further configured to view at least a portion of the radiation receiving surface of the X-ray detector 120, and the depth camera 130 is further configured to generate depth camera image data representative of at least a portion of the radiation receiving surface of the X-ray detector 120. The processor 140 is further configured to determine the spatial relationship between the depth camera 130 and the X-ray detector 120 from the generated depth camera image data representative of at least a portion of the radiation receiving surface of the X-ray detector 120, and to determine the spatial relationship between the X-ray source 110, the X-ray detector 120, and the depth camera 130 using the determined spatial relationship between the depth camera 130 and the X-ray detector 120.

[0035] In this example, the depth camera 130 views a portion of the surface of the X-ray detector 120 while the object 160 is received in the inspection area 150 or in the absence of the object 160. In the latter case, the spatial relationship between the depth camera 130 and the X-ray detector 120 is determined before the object 150 is received in the inspection area. For example, the spatial relationship is determined immediately before the object is received in the inspection area 150, or once an hour, once a day, or at a different time interval. As in the above example, calibration data representing the determined spatial relationship is stored in a database, for example as a look-up table, and accessed by the processor 140 to calculate the spatial transformation described above.

[0036] Continuing with this example, the spatial relationships between the X-ray source 110, the X-ray detector 120, and the depth camera 130 are determined using the spatial relationship between the depth camera 130 and the X-ray detector 120 determined from the generated depth camera image data, and further based on calibration data representative of the relative positions of the X-ray source 110 and the depth camera 130 and / or the relative positions of the X-ray source 110 and the X-ray detector 120. By using this calibration data in combination with the spatial relationship between the depth camera 130 and the X-ray detector 120 determined from the generated depth camera image data, the relative positions of all three of the X-ray source 110, the X-ray detector 120, and the depth camera 130 are determined. The calibration data is stored in a database and accessed by the processor 140 to determine the spatial transformations described above.

[0037] Continuing with this example, in FIG. 4, the depth camera 130 is mechanically coupled to the X-ray source 110, and the calibration data represents the relative position of the X-ray source 110 and the depth camera 130. The depth camera 130 may alternatively be mechanically coupled to the X-ray source 110 and movable to one of a number of selectable fixed positions. In this example, the calibration data represents a number of relative positions. The calibration data representing the fixed relative positions of the X-ray source 110 and the X-ray detector 120 is stored and used in a similar manner in combination with the spatial relationship between the depth camera 130 and the X-ray detector 120 determined from the generated depth camera image data to determine the relative positions of all three of the X-ray source 110, the X-ray detector 120, and the depth camera 130.

[0038] 5 to 9 illustrate various example image representations according to the present disclosure. It is noted that in general, the image representations are provided as two-dimensional images or three-dimensional images.

[0039] 5 is a schematic diagram illustrating a first example of an image representation 170 of depth camera image data projected onto a radiation receiving surface of an X-ray detector 120 from the perspective of a depth camera 130, according to some aspects of the present disclosure. In FIG. 5, the image representation 170 includes projected depth camera image data corresponding to a surface of a patient and a portion of the radiation receiving surface of the X-ray detector 120. The image representation in FIG. 5 allows an operator to position the patient relative to the perimeter of the X-ray detector.

[0040] In some examples, the X-ray detector 120 includes one or more radiation sensitive regions 180 for generating X-ray image data and / or one or more radiation dosimetry regions 190 for generating X-ray dosimetry data. In one example, the processor 140 is configured to generate an overlay image representation including the one or more X-ray radiation sensitive regions 180 and / or a representation of the one or more X-ray radiation dosimetry regions 190, as well as an image representation 170 of the projected depth camera image data. This is illustrated in FIG. 6, which is a schematic diagram illustrating a second example of an image representation 170 of the depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130, according to some aspects of the present disclosure.

[0041] In comparison to Fig. 5, in Fig. 6 the projected depth camera image data is overlaid on top of the example five x-ray dosimetry regions 190 and radiation sensitive regions 180. In Fig. 6 the patient is displayed semi-transparently. The x-ray detector 120 is seen in the background and the projected object 160, i.e. the patient, is provided as a semi-transparent overlay on top of the background. Alternatively, the projected object 160, i.e. the patient, is seen in the background and the x-ray radiation sensitive regions 180 and / or x-ray dosimetry regions 190 are overlaid on top of the patient. The image representation of Fig. 6 allows the operator to position the patient relative to the x-ray radiation sensitive regions 180 and relative to the example five x-ray dosimetry regions 190.

[0042] 6, the overlay of the X-ray radiation sensitive regions 180 and / or X-ray radiation dosimetry regions 190 and the projected depth camera image data is performed by i) detecting the radiation receiving surface of the X-ray detector in the projected depth camera image data, and ii) mapping the location of the X-ray radiation sensitive regions 180 and / or X-ray radiation dosimetry regions 190 to the detected radiation receiving surface of the X-ray detector based on knowledge of its location relative to the radiation receiving surface of the X-ray detector 120. The location of the X-ray radiation sensitive regions 180 and / or X-ray radiation dosimetry regions 190 relative to the radiation receiving surface of the X-ray detector 120 is determined by generating a reference depth camera image including the radiation receiving surface of the X-ray detector 120 without the object 160, i.e., an exemplary patient, and determining the location of the X-ray radiation sensitive regions 180 and X-ray radiation dosimetry regions 190 relative to the reference depth camera image from the corresponding RGB image. Alternatively, the locations of the X-ray radiation sensitive areas 180 and the X-ray dosimetry areas 190 relative to the radiation receiving surface of the X-ray detector 120 are known from calibration data that represents a geometric model of their locations.

[0043] 7 is a schematic diagram illustrating a third example of an image representation 170 of depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130, according to some aspects of the present disclosure. In comparison to FIG. 6, in the image representation 170 of FIG. 7, the surface of the patient is replaced by the surface of the X-ray detector 120 in its silhouette.

[0044] 8 is a schematic diagram illustrating a fourth example of an image representation 170 of depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130, according to some aspects of the present disclosure. In comparison to FIG. 6, in the image representation 170 of FIG. 8, the patient's surface is replaced by its contour overlapping the X-ray detector surface.

[0045] 9 is a schematic diagram illustrating a fifth example of an image representation 170 of depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130, according to some aspects of the present disclosure. In comparison to FIG. 8, in FIG. 9, the image representation 170 provides a schematic visualization of the position of the object 160 relative to the X-ray radiation sensitive area 180 and the X-ray radiation dosimetry area 190. In the schematic visualization, the object is identified in the depth camera image data and substituted with a schematic diagram of the object.

[0046] In one example, one or more corrective actions are further generated to obtain a more optimal position of the patient relative to the X-ray detector 120. In this example, the processor 140 is further configured to calculate a displacement between a position of the one or more features in the image representation 170 of the projected depth camera image data and an expected position of the one or more features relative to i) the representation of the one or more X-ray radiation sensitive regions 180 and / or ii) the representation of the one or more X-ray radiation dosimetry regions 190. The processor 140 is further configured to generate an output representative of one or more corrective actions to reduce the displacement based on the calculated displacement.

[0047] In this example, image processing techniques are used to identify features such as the patient's silhouette on the surface of the X-ray detector, or the position of the limbs, or the head, from the depth camera image data. The expected location of the feature is determined based on user input of the type of imaging operation to be performed, based on automatic detection of the current location of the patient's anatomical landmarks or regions, based on a classification of the patient's view, or based on a combination of these factors. For example, if a chest imaging operation is to be performed, the silhouette of the patient's torso on the surface of the detector is identified and the corrective action includes "move the torso 5 centimeters to the right" to align the patient's torso with the X-ray radiation sensitive region 180. The corrective action is output in the form of an audio instruction or displayed on the monitor. For example, a directional arrow with the distance the object should be moved is superimposed on the relevant portion of the image representation 170.

[0048] In one example, the depth camera 130 further generates optical image data. In this example, the processor 140 generates an image representation 170 of the projected depth camera image data such that the image representation includes the optical image data. For example, an RGB-D camera is used to provide optical image data in addition to the depth camera image data. The optical image data is in the visible or infrared portion of the electromagnetic spectrum. The optical image data is included in the image representation 170 by generating an overlay of the optical image data and a representation of the projected depth camera image data. The overlay further assists the user in positioning the patient relative to the x-ray detector 120.

[0049] Returning to FIG. 4, in most circumstances, the portion of the surface 210 of the object 160 that is "visible" from the viewpoint of the X-ray source 110 and projected onto the surface of the X-ray detector 120 can be determined to a very good approximation from the depth camera image data, regardless of its offset position. However, when the offset is large, the projection plane of the object is incomplete on the opposite side of the X-ray source relative to the offset, i.e., the portion below the projected image data 220 in FIG. 4. In such circumstances, a more complete projection of the depth camera image data from the viewpoint of the X-ray source 110 onto the radiation receiving surface of the X-ray detector 120 can be obtained by combining projection data obtained from different rotational positions of the depth camera relative to the X-ray source 110. Thus, in one example, the depth camera 130 is mechanically coupled to the X-ray source 110 and the depth camera 130 is radially offset with respect to an axis 200 passing through the centers of the X-ray source 110 and the X-ray detector 120, or the depth camera 130 is radially offset with respect to an axis passing through the center of the radiation beam emitted by the X-ray source 110. The depth camera 130 is rotatable about said axis 200 to generate depth camera image data from different rotational positions with respect to the axis.

[0050] In this example, both the depth camera 130 and the X-ray source can rotate together around an axis, i.e., there is no relative motion between the X-ray source and the X-ray detector during rotation, or the depth camera 130 can rotate independently with respect to the X-ray source, in which case the X-ray detector remains stationary but the depth camera rotates. In this example, the depth camera is freely rotated to any angular position, or in fact the depth camera is rotated to one of a number of selectable fixed rotation positions. The rotation positions are distinguished, for example, every 90 degrees, or every 180 degrees, or every other angle. In doing so, a more accurate positioning of the object 160 relative to the X-ray detector 110 is achieved.

[0051] In one example, a further image representation of the projected depth camera image data is further provided. In this example, the processor 140 generates an image representation 170 of the projected depth camera image data from the perspective of the X-ray source 110. This projection is determined based on the aforementioned predetermined spatial relationship between the X-ray source 110, the X-ray detector 120, and the depth camera 130. This further image representation is further used to assist the operator in positioning the object relative to the X-ray detector.

[0052] In one example, an X-ray image is further generated, in which the X-ray detector 120 is configured to generate X-ray image data representative of the attenuation of X-ray radiation emitted by the X-ray source 110 within the examination region 150, and the processor 140 is further configured to generate an X-ray image representation of the X-ray image data.

[0053] In another example, a computer-implemented method is provided for use with X-ray imaging system 100. The computer-implemented method of generating an image representation 170 using an X-ray imaging system comprising an X-ray source 110, an X-ray detector 120, and a depth camera 130, the X-ray source 110 and the X-ray detector 120 separated by an inspection area 150 for performing an X-ray imaging operation on an object when the object is received within the inspection area, and the depth camera 130 configured to view the inspection area 150 for generating depth camera image data representative of the object when the object is received within the inspection area, the method comprising: Receiving depth camera image data; projecting the depth camera image data onto a radiation receiving surface of an x-ray detector 120 from a perspective of an x-ray source 110; generating an image representation 170 of the depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130; has.

[0054] In another example, a computer program product is provided for use with X-ray imaging system 100. The computer program product comprises instructions that, when executed by one or more processors 140, cause the one or more processors 140 to perform a method of generating an image representation 170 using an X-ray imaging system comprising an X-ray source 110, an X-ray detector 120, and a depth camera 130, the X-ray source 110 and the X-ray detector 120 being differentiated into inspection areas 150 for performing X-ray imaging operations on an object when received within the inspection area, and the depth camera 130 being configured to view the inspection areas 150 for generating depth camera image data representative of the object when received within the inspection area. The method comprises: receiving depth camera image data; projecting the depth camera image data onto a radiation receiving surface of an x-ray detector 120 from the perspective of an x-ray source 110; generating an image representation 170 of the depth camera image data projected onto the radiation receiving surface of the X-ray detector 120 from the perspective of the depth camera 130; has.

[0055] The above examples are to be understood as illustrative and non-limiting of the present disclosure. Further examples are further envisaged. For example, the examples described with respect to an X-ray imaging system are further provided in a corresponding manner by a computer-implemented method, or by a computer program product, or by a computer-readable storage medium. It is to be understood that features described with respect to any one example may be used alone or in combination with other described features, in combination with one or more other features of the example, or in combination with other examples. Moreover, equivalents and modifications not described above may further be employed without departing from the scope of the invention as defined in the appended claims. In the claims, the word "comprising" does not exclude other elements or operations, and singular elements do not exclude a plurality. The mere fact that certain features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be advantageously used. Any reference signs in the claims should not be taken as limiting the scope thereof.

Claims

1. an X-ray source; an x-ray detector separated from the x-ray source by the inspection region for performing x-ray imaging operations on an object when the object is received within the inspection region; a depth camera viewing the inspection area to generate depth camera image data representative of the object when received within the inspection area; receiving the depth camera image data; projecting the depth camera image data onto a radiation receiving surface of the X-ray detector from a perspective of the X-ray source; generating an image representation of the depth camera image data projected onto the radiation receiving surface of the X-ray detector from a viewpoint of the depth camera; A processor that performs An X-ray imaging system comprising:

2. 2. The X-ray imaging system of claim 1, wherein the processor projects the depth camera image data from the viewpoint of the X-ray source onto the radiation receiving surface of the X-ray detector and / or generates the image representation of the depth camera image data projected from the viewpoint of the depth camera onto the radiation receiving surface of the X-ray detector based on a predetermined spatial relationship between the X-ray source, the X-ray detector, and the depth camera.

3. the depth camera views at least a portion of the radiation receiving surface of the X-ray detector; the depth camera generating depth camera image data representative of the at least a portion of the radiation receiving surface of the X-ray detector; the processor: determining a spatial relationship between the depth camera and the X-ray detector from the generated depth camera image data representative of the at least a portion of the radiation receiving surface of the X-ray detector; determining the spatial relationship between the X-ray source, the X-ray detector, and the depth camera using the determined spatial relationship between the depth camera and the X-ray detector; 3. The X-ray imaging system of claim 2, wherein the X-ray imaging system performs the following steps.

4. 4. The X-ray imaging system of claim 3, wherein the processor determines the spatial relationship between the X-ray source, the X-ray detector, and the depth camera further based on calibration data representing a relative position between the X-ray source and the depth camera and / or a relative position between the X-ray source and the X-ray detector.

5. 3. The X-ray imaging system of claim 2, wherein the predetermined spatial relationship between the X-ray source, the X-ray detector, and the depth camera is determined based on calibration data representing relative positions of the X-ray source, the X-ray detector, and the depth camera.

6. the X-ray detector comprises one or more radiation sensitive areas for generating X-ray image data and / or one or more radiation dosimetry areas for generating X-ray dosimetry data; 2. The X-ray imaging system of claim 1, wherein the processor generates an overlay representation including the one or more X-ray radiation sensitive regions and / or a representation of the one or more X-ray radiation dosimetry regions and the image representation of the projected depth camera image data.

7. 7. The X-ray imaging system of claim 6, wherein the processor calculates a displacement between a position of one or more features in the image representation of the projected depth camera image data and an expected position of the one or more features relative to i) the representation of the one or more X-ray radiation sensitive regions and / or ii) the representation of the one or more X-ray radiation dosimetry regions, and wherein the processor generates an output representing one or more corrective actions to reduce the displacement based on the calculated displacement.

8. the depth camera generates optical image data; The x-ray imaging system of claim 1 , wherein the processor generates the image representation of the projected depth camera image data such that the image representation includes the optical image data.

9. the depth camera is mechanically coupled to the x-ray source; the depth camera is radially offset with respect to an axis passing through the center of the X-ray source and the X-ray detector, or the depth camera is radially offset with respect to an axis passing through the center of a radiation beam emitted by the X-ray source; The x-ray imaging system of claim 1 , wherein the depth camera is rotatable about the axis to generate the depth camera image data from different rotational positions relative to the axis.

10. The x-ray imaging system of claim 1 , wherein the processor generates an image representation of the projected depth camera image data from a perspective of the x-ray source.

11. the x-ray detector generates x-ray image data representative of the attenuation of x-ray radiation emitted by the x-ray source within the examination region; The x-ray imaging system of claim 1 , wherein the processor generates an x-ray image representation of the x-ray image data.

12. The X-ray imaging system of claim 1 , wherein the depth camera image data represents a shape of a surface of the object.

13. 2. The X-ray imaging system of claim 1, wherein the image representation of the projected depth camera image data comprises an overlay of a portion of the object's surface, a portion of the object's silhouette, or a portion of the object's contour on the radiation receiving surface of the X-ray detector.

14. A computer-implemented method for generating an image representation using an X-ray imaging system, comprising: providing an X-ray source, an X-ray detector, and a depth camera, the X-ray source and the X-ray detector separated by an inspection area for performing X-ray imaging operations on an object when the object is received within the inspection area, and the depth camera viewing the inspection area to generate depth camera image data representative of the object when the object is received within the inspection area; receiving the depth camera image data; projecting the depth camera image data onto a radiation receiving surface of the X-ray detector from a perspective of the X-ray source; generating an image representation of the depth camera image data projected onto the radiation receiving surface of the X-ray detector from a viewpoint of the depth camera; 10. A computer-implemented method comprising:

15. A non-transitory computer-readable medium for storing executable instructions, the executable instructions causing a method to be performed for generating an image representation using an X-ray imaging system, the method comprising: providing an X-ray source, an X-ray detector, and a depth camera, the X-ray source and the X-ray detector separated by an inspection area for performing X-ray imaging operations on an object when the object is received within the inspection area, and the depth camera viewing the inspection area to generate depth camera image data representative of the object when the object is received within the inspection area; receiving the depth camera image data; projecting the depth camera image data onto a radiation receiving surface of the X-ray detector from a perspective of the X-ray source; generating an image representation of the depth camera image data projected onto the radiation receiving surface of the X-ray detector from a viewpoint of the depth camera; 1. A non-transitory computer-readable medium having:

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