Dental X-ray imaging system and method for dental X-ray imaging of a patient

Abstract

The present invention relates to a dental X-ray imaging system (100) for performing dental X-ray imaging of a patient (600). The system (100) includes a dental X-ray imaging unit (102) and a control system (106). The dental X-ray imaging unit (102) includes an X-ray source section (114), an X-ray imaging detector section (116), and a gantry section (112) including the source section (114) and the imaging detector section (116). The control system (106) is configured to acquire at least one optical image (105) of the patient (600), receive a scan request including region of interest (ROI) data, and define an ROI location based on the ROI data, the at least one optical image (105), dental atlas data (1116), and at least one image analysis model (1118) formed based on previously acquired reference image data. The present invention also relates to a method, a computer program, and a tangible, non-volatile computer readable medium for performing dental x-ray imaging of a patient (600).

Description

[Technical Field]

[0001] The present invention relates generally to the field of dental x-ray imaging. [Background technology]

[0002] Generally, correct patient positioning is one of the most time-consuming tasks performed by a user of a dental x-ray imaging device, e.g., an operator, during the dental x-ray imaging process, but it is also one of the most important tasks. Conventionally, the patient may be positioned in the dental x-ray imaging device using various support techniques to keep the patient's head as still as possible.

[0003] Traditional support means are chin rests, static bite sticks, and head supports that support the forehead, temples, and / or the back of the skull. Additionally, different types of straps may be used to position the patient as rigidly as possible. Furthermore, some dental x-ray imaging devices have a bite stick that is attached to the dental x-ray imaging device such that the attachment means allows the bite stick to move in several directions.

[0004] A traditional method is to use scout imaging, which is a small set of panoramic images or two projected images taken at a 90-degree angle that can be used as a three-dimensional (3D) aiming aid.

[0005] In this type of approach, precise setup is crucial. Once patient positioning (targeting) is complete, the patient must remain stable throughout the entire imaging process. If the patient or the X-ray imaging unit moves between positioning and X-ray imaging, i.e., if the patient's position relative to the X-ray imaging unit changes, the resulting X-ray images will be diagnostically useless. The movement of the patient and / or the X-ray imaging unit during the scanning phase can cause significant artifacts in the resulting X-ray images. These motion-induced artifacts must be corrected, if possible, when reconstructing the image data acquired during the scanning phase into dental X-ray images, or can be reduced by software-based correction. Artifacts caused by movement can significantly affect the quality of dental X-ray images, resulting in, for example, blurred or distorted images.

[0006] Furthermore, in panoramic imaging, the patient's anatomical shape is typically unknown before the panoramic image is taken. The quality of the panoramic image is heavily influenced by how well the predefined imaging layers correspond to the patient's actual anatomical shape, e.g., the dental arch. Typically, an average shape is used for all patients, which may result in suboptimal image quality. Furthermore, correct patient positioning is important, especially in panoramic imaging. If the patient is not positioned correctly, additional X-rays of the patient may be required.

[0007] Typically, the imaging workflow is manually controlled by an operator, and therefore the quality of the dental x-ray images obtained and the duration of imaging may depend on actions by the operator. Summary of the Invention

[0008] The following is a simplified summary in order to provide a basic understanding of some aspects of various invention embodiments. This summary is not an extensive overview of the invention, and is not intended to identify key or critical elements of the invention or to delineate the scope of the invention. The following summary merely introduces some concepts of the invention in a simplified form as a prelude to describing example embodiments of the invention in more detail.

[0009] It is an object of the present invention to provide a dental x-ray imaging system, method, computer program, and computer readable medium for dental x-ray imaging of a patient, and a method, computer program, and computer readable medium for determining aligned dental atlas data for a patient. Another object of the present invention is to provide a dental x-ray imaging system, method, computer program, and computer readable medium for dental x-ray imaging of a patient, and a method, computer program, and computer readable medium for determining aligned dental atlas data for a patient, which improve the quality of dental x-ray images.

[0010] The object of the invention is achieved by a dental X-ray imaging system, a method, a computer program and a computer readable medium as defined by the respective independent claims.

[0011] According to a first aspect, there is provided a dental X-ray imaging system for performing dental X-ray imaging of a patient, the system comprising: a dental X-ray imaging unit including an X-ray source section for emitting X-rays, an X-ray imaging detector section for incident X-rays from the X-ray source section, and a gantry section including the X-ray source section and the imaging detector section; and a control system configured to acquire at least one optical image of the patient (600), receive a scan request including region of interest (ROI) data, and define an ROI position based on the ROI data, the at least one optical image, dental atlas data, and at least one image analysis model formed based on previously collected reference image data.

[0012] The at least one optical image of the patient may include at least one optical image in which the patient's dentition is at least partially visible, and the control system may be configured to determine a plurality of head landmarks for the patient based on the at least one optical image of the patient and the at least one image analysis model, select a plurality of atlas landmarks corresponding to the plurality of head landmarks for the patient based on the dental atlas data, and register the plurality of atlas landmarks and the plurality of head landmarks for the patient to determine aligned dental atlas data for the patient.

[0013] The control system may be configured to define the ROI location based on the ROI data and the patient's determined, registered dental atlas data.

[0014] Alternatively or additionally, the control system may be further configured to determine exposure parameters for scanning the patient based on imaging mode data further included in the scan request, at least one optical image of the patient, and at least one image analysis model.

[0015] The control system may be configured to determine a plurality of head landmarks of the patient based on at least one optical image of the patient and at least one image analysis model, determine head size data of the patient based on the plurality of head landmarks of the patient, and use the head size data in determining the exposure parameters.

[0016] The control system may further be configured to determine classification data for the patient based on at least one optical image of the patient and the at least one image analysis model, and to use the classification data in determining the exposure parameters.

[0017] Alternatively or additionally, the control system may be further configured to determine at least one head landmark of the patient based on at least one optical image of the patient and at least one image analysis model, determine height data of the patient based on the at least one head landmark of the patient, and adjust the height of components of the dental X-ray imaging unit using the determined height data.

[0018] Alternatively or additionally, the control system may be further configured to determine a plurality of body landmarks of the patient based on at least one optical image of the patient and at least one image analysis model, determine width data of the patient based on the plurality of body landmarks of the patient, and use the determined width data to reduce a risk of collision between the patient and a gantry portion of the dental X-ray imaging apparatus.

[0019] The dental x-ray imaging device may include at least one optical imaging device configured to capture at least one optical image of the patient (600).

[0020] The ROI data may include a representation of at least one of a single tooth, a range of teeth, one dental arch, both dental arches, a temporomandibular joint (TMJ), the entire dentition, and a TMJ.

[0021] Alternatively or additionally, the control system may be further configured to generate patient position correction data for positioning the patient based on at least one optical image of the patient and the at least one image analysis model.

[0022] According to a second aspect, there is provided a dental imaging method performed by the X-ray dental imaging system described above, the method comprising: acquiring at least one optical image of a patient; receiving a scan request including region of interest (ROI) data; and defining the ROI location based on the ROI data, the at least one optical image, dental atlas data, and at least one image analysis model formed based on previously collected reference image data.

[0023] According to a third aspect, there is provided a computer program comprising instructions which, when the program is run by a computer, cause the computer to carry out the method set out above.

[0024] According to a fourth aspect, there is provided a tangible, non-volatile computer readable medium containing instructions that, when executed by a computer, cause the computer to perform the method set forth above.

[0025] According to a fifth aspect, there is provided a method for determining aligned dental atlas data of a patient, the method comprising: acquiring at least one optical image of the patient, in which the patient's dentition is at least partially visible; determining a plurality of head landmarks of the patient based on the at least one optical image of the patient and at least one image analysis model formed based on previously collected reference image data; selecting a plurality of atlas landmarks corresponding to the plurality of head landmarks of the patient based on the dental atlas data; and registering the plurality of atlas landmarks with the plurality of head landmarks of the patient to determine the aligned dental atlas data of the patient.

[0026] According to a fifth aspect, there is provided a computer program comprising instructions which, when the program is run by a computer, cause the computer to carry out the method set out above.

[0027] According to a sixth aspect, there is provided a tangible, non-volatile computer readable medium containing instructions that, when executed by a computer, cause the computer to perform the method set forth above.

[0028] Various exemplary and non-limiting embodiments of the present invention, both as to structure and method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific exemplary and non-limiting embodiments when read in connection with the accompanying drawings.

[0029] In this specification, the verbs "comprise" and "include" are used as open limitations that neither exclude nor require the presence of unrecited features. Features recited in dependent claims are mutually freely combinable unless expressly stated otherwise. Furthermore, as used throughout this specification, the use of "a" or "an", i.e., the singular, does not exclude the plural.

[0030] Embodiments of the present invention are illustrated by way of example, and not by way of limitation, in the figures of the accompanying drawings. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a diagram illustrating an example of a dental x-ray imaging system. [Figure 2] 1 is a diagram illustrating an example of a method for dental imaging of a patient; [Figure 3] FIG. 2 is a diagram illustrating an example of a reference imaging position for providing at least a portion of the reference image data. [Figure 4] FIG. 1 illustrates a schematic diagram of an example of a method for determining registered dental atlas data for a patient. [Figure 5] 1A to 1B are diagrams schematically illustrating examples of a plurality of head landmarks of a patient. [Figure 6A] FIG. 10 is a diagram illustrating an example of a method for defining coordinate transformation data. [Figure 6B] FIG. 10 is a diagram illustrating an example of extracting device orientation data. [Figure 6C] FIG. 10 is a diagram illustrating another example of extraction of device orientation data. [Figure 7]10A to 10D are diagrams showing an example of movement of the gantry part to the start position of the scan trajectory. [Figure 8A] FIG. 1 illustrates a schematic diagram of an example of a method for determining exposure parameters for scanning a patient. [Figure 8B] FIG. 10 is a diagram schematically illustrating yet another example of multiple head landmarks for a patient. [Figure 9A] 10A and 10B are diagrams illustrating an example of a method for adjusting the height of components of a dental X-ray imaging unit. [Figure 9B] FIG. 10 is a diagram illustrating an example of a height offset value. [Figure 10A] 1 is a diagram illustrating an example of a method for reducing the risk of collision between a patient and a gantry part of a dental X-ray imaging unit. [Figure 10B] FIG. 1 is a diagram illustrating an example of a number of body landmarks of a patient. [Figure 11] FIG. 1 is a diagram illustrating an example of a control system for a dental X-ray imaging system. [Figure 12] FIG. 10 is a diagram illustrating an example of a method for detecting patient readiness. [Figure 13] FIG. 10 is a diagram illustrating an example of a method for detecting the readiness of a device. DETAILED DESCRIPTION OF THE INVENTION

[0032] The following vocabulary is used herein for the various stages of the dental x-ray imaging process: The term radiating refers simply to the stage consisting of irradiation, i.e., the stage in which an x-ray source directs an x-ray beam through an object to an x-ray imaging detector. During irradiation, the object is expected to remain as still, i.e., immobile, as possible. During irradiation, one or more components of the dental x-ray imaging device may move. The term scanning refers to the stage consisting of radiation irradiation and movement of one or more components of the dental x-ray imaging unit. Scanning does not include positioning one or more components of the x-ray imaging unit in the correct location to provide an x-ray image. The term imaging refers to the entire process consisting of irradiation, scanning, and positioning.

[0033] FIG. 1 illustrates an example of a dental X-ray imaging system 100 for performing dental X-ray imaging of a patient 600 (for clarity, the patient 600 is not shown in FIG. 1 ). The imaging system 100 includes a dental X-ray imaging unit 102 that acquires X-ray image data from an object, such as a patient or a calibration object, during dental X-ray imaging, e.g., extraoral dental X-ray imaging. The acquired X-ray image data is used to form a two-dimensional (2D) X-ray image or to reconstruct a three-dimensional (3D) X-ray volume from at least a portion of the imaged object. The dental X-ray imaging system 100 further includes a control system 106. The control system 106 may be electrically and / or cooperatively coupled to the dental X-ray imaging unit 102. The control system 106 may be implemented as a standalone unit or as a distributed control environment among multiple standalone units providing distributed control resources. Preferably, the computing unit 106 may be an embedded computer. The control system 106 may include, for example, a control unit of the dental X-ray imaging unit 102. The control system 106 may further include a computing unit of at least one imaging device 104a, 104b of the dental X-ray imaging system 100 and / or a computing unit external to the dental X-ray imaging unit 102. The control unit of the dental X-ray imaging unit 102 is configured to at least partially control the operation of the dental X-ray imaging unit 102. The control unit of the dental X-ray imaging unit 102 may be located proximate to the dental X-ray imaging unit 102, or the control unit of the dental X-ray imaging unit 102 may be integrated into the dental X-ray imaging unit 102.

[0034] The dental X-ray imaging unit 102 may be configured to perform different types of imaging procedures (i.e., imaging modes), including, but not limited to, computed tomography (CT) imaging and / or panoramic imaging. CT imaging may be cone-beam CT (CBCT) imaging, in which the beam is a cone-shaped beam, or other types of CT imaging, in which, for example, the beam is a pyramidal beam, a half-moon-shaped cone beam, or any other shaped beam. CT imaging provides (i.e., generates) X-ray image data for reconstructing a 3D volume from at least a portion of the imaged object. Panoramic imaging may be, for example, standard panoramic imaging, pediatric panoramic imaging, orthozonal panoramic imaging, wide-arch panoramic imaging, orthogonal panoramic imaging, etc. Panoramic imaging provides X-ray image data for forming a panoramic 2D image. Additionally, if the dental X-ray imaging unit 102 includes the components necessary for cephalometric imaging, the dental X-ray imaging unit 102 may be configured to perform cephalometric imaging. Cephalometric imaging may be, for example, pediatric lateral projection, lateral cephalometric projection, posterior anterior cephalometric projection, and / or the like. Cephalometric imaging provides x-ray image data for forming a two-dimensional cephalometric image. Figure 1 shows only one example of a dental x-ray imaging unit 102 for use with the concepts of the present disclosure.

[0035] The dental X-ray imaging unit 102 includes a carriage portion 101 that can be movably supported on a support column 103. The carriage portion 101 can be moved up and down in a height direction (Z), i.e., vertical direction, by a guide motor (not shown in FIG. 1 ) configured to move the carriage 101 up and down in the height direction along the support column 103. The upper shelf 110 is configured to support a gantry portion, i.e., a rotating portion 112, that can rotate in a horizontal plane relative to the upper shelf 110. The upper shelf 110 and / or the gantry portion 112 may include a rotation motor (not shown in FIG. 1 ) configured to rotate the gantry portion 112. Alternatively or additionally, the upper shelf 110 may include a pivot motor (not shown in FIG. 1 ) configured to pivot the upper shelf 110 about the support column 103. Alternatively or additionally, the dental X-ray imaging unit 102 can be mounted to a support structure (not shown in FIG. 1 ), such as a wall, so as to be supported by the support column 103.

[0036] The dental X-ray imaging unit 102 further includes an X-ray source section 114 and an X-ray imaging detector section 116 used to acquire X-ray image data. The gantry section 112 embodies and supports the source section 114 and the imaging detector section 116. The gantry section 112 may have substantially the shape of the letter C, as shown in FIG. 1, in which case the X-ray source section 114 may be mounted at one end of the gantry section 112 and the X-ray imaging detector section 116 may be mounted at the other end of the gantry section 112 such that the source section 114 and the X-ray imaging detector section 116 face each other. The X-ray source section 114 includes an X-ray source that emits X-rays (i.e., generates an X-ray beam) and emits X-rays through an object being imaged, for example, the head of a patient 600, to the X-ray imaging detector section 116, which includes at least one X-ray detector on which the X-rays emitted from the source section 114 are incident. The X-ray imaging detector unit 116 further generates X-ray image data from the object that has been irradiated with X-rays, ie, imaged.

[0037] The X-ray imaging unit also includes a collimator (not shown in FIG. 1 ) for the X-ray source unit 114 to limit and / or shape the beam of X-rays. The X-rays pass through a portion of the object, e.g., a patient's anatomical structure, such as the patient's head. The anatomical structure through which the X-rays pass may absorb varying amounts of X-ray energy. After passing through the object, the attenuated X-rays are incident on the X-ray imaging detector unit 116. The X-ray imaging detector unit 116 is configured to convert the magnitude of the incident X-ray energy and generate digitized output, i.e., X-ray image data, representative of the unabsorbed X-rays in at least one X-ray detector. A collection of digitized outputs from the X-ray imaging detector unit 116 corresponding to a single emission of the X-ray beam from the X-ray source unit 114 may be referred to as a projection image of the object being imaged, e.g., the head of the patient 600.

[0038] Additionally, the dental X-ray imaging unit 102 may include patient supports 124, 126 (shown in FIG. 1 , but not necessarily as shown) that can be used to support the patient 600 during CT or panoramic imaging. The patient supports 124, 126 may include a chin support 124 and / or a head support 126. The chin support 124 may support the tip of the patient's 600's chin, and the head support 126 may support the patient's 600's forehead or temples. The dental X-ray imaging unit 102 may include a lower shelf 122 extending from the carriage 101. The lower shelf 122 may include the chin support 124, similar to the exemplary dental X-ray imaging unit 102 of FIG. 1 . The head support 126 may extend from the upper shelf 110 through the rotating portion 112, similar to the exemplary dental X-ray imaging unit 102 of FIG. 1 . Alternatively, the lower shelf 122 may also include a head support 126. The patient support, i.e., the chin support 124 and / or the head support 126, may be optional, and the positioning of the patient 600 may be accomplished in other manners. The dental x-ray imaging unit 102 may further include a handle 128 for the patient 600 to grasp.

[0039] The gantry portion 112 may be rotated by, for example, a rotary motor. As the gantry portion 112 rotates, the X-ray source portion 114 and the X-ray imaging detector portion 116 rotate along a scan trajectory around the object being imaged, for example, around an axis of rotation. As the X-ray source portion 114 and the X-ray imaging detector portion 116 are rotated around the object, for example, the head of the patient 600, the X-ray imaging unit 102 operates to acquire multiple projection images of the object taken at incremental rotation angles. A dental X-ray image may be formed from the multiple projection images by reconstructing the X-ray image data into a dental X-ray image.

[0040] The dental x-ray imaging system 100 may further include at least one optical imaging device 104a, 104b. The at least one optical imaging device 104a, 104b may include at least one external imaging device 104a and / or at least one internal imaging device 104b. The at least one external imaging device 104a is located external to the dental x-ray imaging unit 102. In other words, the at least one external imaging device 104a may be a device that is not part of the dental x-ray imaging unit 102. Because at least some parts of the dental X-ray imaging unit 102 (e.g., the patient support units 124, 126, the X-ray source unit 114, and / or the X-ray imaging detector unit 116) may disturb the lighting environment for capturing optical images when using the at least one internal imaging device 104b, using the at least one external imaging device 104a may provide a better lighting environment for collecting optical image data compared to using the at least one internal imaging device 104b. Alternatively or additionally, capturing optical images using the at least one external imaging device 104a is simple and easy. The at least one internal imaging device 104b may be disposed in association with the dental X-ray imaging unit 102, for example, embedded within the dental X-ray imaging unit 102. For example, the at least one internal imaging device 104b may be attached (e.g., fixed) to the dental X-ray imaging unit 102. 1 shows only one non-limiting example of at least one internal imaging device 104b; any other number of internal imaging devices 104b may be used and positioned at any other location on the dental x-ray imaging unit 102. At least one imaging device 104a, 104b may be a 2D imaging device and / or a 3D imaging device. Preferably, at least one imaging device 104a, 104b is a 3D imaging device, i.e., a range imaging device. The 3D imaging device may be based on any 3D imaging technology, such as stereo triangulation, light sheet triangulation, structured light, time of day light, interferometry, coded aperture, and / or any other 3D imaging technology.The 3D imaging device may be a self-contained unit that includes all hardware and software related to 3D imaging, and possibly an internal computing unit, within the same module. Alternatively, the 3D imaging device may be a collection of separate components arranged in a 3D imaging configuration, such as two optical cameras (e.g., a camera pair) arranged in a stereoscopic configuration with 3D calculations performed in an external computing unit (e.g., a control unit). The 2D imaging device may be, for example, an optical camera and / or another 2D imaging device. By way of non-limiting example, the at least one external imaging device 104a may be, but is not limited to, an optical camera, a mobile device (e.g., a mobile phone, a tablet computer) including at least one optical camera, and / or a standalone 3D face scanner system. The at least one internal optical imaging device 104b may be a multi-function optical imaging device. In other words, the at least one internal optical imaging device 104b may also be used for one or more other operations or functions, such as, but not limited to, patient positioning, motion detection, and / or motion compensation.

[0041] At least some exemplary aspects of a method for dental imaging of a patient 600 will now be defined with reference to Figure 2, which illustrates the method as a flow chart, and which is performed by the dental x-ray system 100 described above.

[0042] As step 210, the control system 106 acquires at least one optical image 105 of the patient 600. The at least one optical image 105 of the patient 600 may be captured using at least one optical imaging device 104a, 104b of the dental x-ray system 102, e.g., at least one external imaging device 104a and / or at least one internal imaging device 104b. The control system 106 may acquire the at least one optical image 105 of the patient 600 from the at least one optical imaging device 104a, 104b, e.g., from the at least one external imaging device 104a and / or from the at least one internal imaging device 104b. Alternatively, the control system 106 may acquire the at least one optical image 105 of the patient 600 from a database in which at least one optical image 105 captured using the at least one optical imaging device 104a, 104b is stored. 1 illustrates a non-limiting example in which the acquired at least one optical image 105 is captured by at least one external optical imaging device 104a, although alternatively or additionally, the acquired at least one optical image 105 may be captured by at least one internal optical imaging device 104b. According to a non-limiting example, an optical image belonging to the at least one optical image 105 of the patient 600 may be captured when the patient 600 enters a room in which the dental X-ray imaging unit 102 is located. According to another non-limiting example, the at least one optical image 105 of the patient 600 may already be captured before the patient 600 enters a room in which the dental X-ray imaging unit 102 is located, as long as the at least one optical image of the patient 600 has been captured substantially recently. The at least one optical image 105 may be a still image and / or a moving image. The at least one optical image 105 of the patient 600 may include at least one face image of the patient 600, at least one upper torso image of the patient 600, and / or at least one full body image of the patient 600.

[0043] In step 220, the control system 106 receives a scan request. The scan request can be received locally or remotely via the user interface units 140a, 140b. The user interface units 140a, 140b may be located, for example, at the same location as the X-ray imaging unit 102, i.e., the scan request may be received locally. For example, the X-ray imaging unit 102 may include a user interface unit 140a, e.g., a touch screen, like the exemplary dental X-ray imaging unit 102 of FIG. 1. An operator of the X-ray imaging unit 102 can input the scan request via the user interface unit 140a. Alternatively or additionally, the user interface unit 140b may be located at a location separate from the location where the X-ray imaging unit 102 is located, i.e., the user interface unit 140b may be located remotely from the X-ray imaging unit 102 and communicatively coupled to the control system 106. In this case, the scan request may be received remotely. Note that the scan request includes region of interest (ROI) data. The scan request may further include imaging mode data. The imaging mode data may include an indication of the imaging mode (i.e., imaging modality) for the scan, such as CT imaging and possibly a type of CT imaging, panoramic imaging and possibly a type of panoramic imaging, or head imaging and possibly a type of head imaging. The ROI data may include an indication of one or more regions of the patient (e.g., one or more target anatomical structures) to be included in the scan, i.e., the ROI of interest. For example, the ROI data may include, but is not limited to, an indication of at least one of a single tooth, a range of teeth, a dental arch (either upper or lower), both dental arches (upper and lower), one temporomandibular joint (TMJ), both TMJs, the entire dentition, and the temporomandibular joint. The scan request may further include patient identification data (e.g., patient name, patient identification number, photograph, fingerprint, retinal scan, facial recognition, and / or other biometric data, etc.) and / or resolution data including an indication of the resolution to be used for the scan.Although step 210 is presented before step 220 in FIG. 2, step 220 may be performed before or simultaneously with step 210 .

[0044] In step 230, the control system 106 defines an ROI position on the patient 600 based on the ROI data, at least one optical image 105, dental atlas data 1116, and at least one image analysis model 1118. The defined ROI position on the patient 600 may depend on the imaging mode. For example, in CT imaging, the defined ROI position may be a field of view (FOV) position. For example, in panoramic imaging, the defined ROI position may be a position of an imaging layer.

[0045] The dental atlas data 1116 may consist of atlas anatomical data. The anatomical data of the dental atlas data 1116 may include, for example, atlas anatomical structure data. The atlas anatomical structure data may include, for example, one or more anatomical structures, such as teeth, dental arches (upper and / or lower jaw), TMJ(s), mandibular condyle(s), chin, mental notch, acanthion, tragus(s), ear canal(s), sinus(s), orbit(s) (e.g., the inferior orbit of the eye), and / or any other anatomically related structure. The atlas anatomical data may further include atlas landmark data. The atlas landmark data may include the locations of multiple atlas landmarks, for example, multiple mandibular atlas landmarks, multiple maxillary atlas landmarks, and / or one or more other landmarks. The plurality of atlas landmarks may include, for example, a predetermined number of maxillary anterior teeth (e.g., the three most central teeth on each side, i.e., the teeth from the canine to the right canine, including both canines), a predetermined number of mandibular anterior teeth (e.g., the three most central teeth on each side), mandibular condyle landmarks, chin landmarks, mandibular notch landmarks, acanthion, nasal cross landmarks, tragus landmark(s), ear canal landmark(s), paranasal sinus landmark(s), temporomandibular joint landmarks, orbital landmarks (e.g., infraorbital landmarks), and / or other anatomically related structure landmarks. The atlas landmark data may further include labels, e.g., identifiers (IDs), for the plurality of atlas landmarks. Atlas anatomical data may typically be extracted from CT images, e.g., CBCT images, medical CT images, or other radiological images. Typically, these CT images are 3D images, but the CT images may also be 2D or 4D images. The atlas anatomical data may be extracted from a single subject or from multiple subjects. Alternatively, the atlas anatomical data may be created without CT images. Thus, the atlas anatomical data may be synthetic or generic. In addition to the atlas anatomical data, the dental atlas data 1116 may further include atlas image data.The atlas image data may include, for example, atlas ROI data. The atlas ROI data may include the locations of one or more possible ROI locations. For example, in the case of CT imaging, the locations of the one or more possible ROI locations may include the locations of one or more single teeth, tooth ranges, dental arches (upper and / or lower), temporomandibular joints, the entire dentition and temporomandibular joint, and / or any other specific ROI locations. For example, in the case of panoramic imaging, the one or more possible ROI locations may include the locations of one or more imaging layers. Preferably, the atlas ROI data may include all possible ROI locations. Each possible ROI location may include, for example, a possible ROI center. The atlas ROI data may further include labels for one or more possible ROI locations. The atlas imaging data may further include atlas scan trajectory data and / or other shape-dependent imaging data. The atlas scan trajectory data may include, for example, rotation axis data, rotation angle data, exposure parameter data, sharp layer data (in the case of panoramic imaging), and / or timing diagram data. The rotation axis data may include the position of the mechanical (i.e., physical) rotation axis, i.e., the mechanical center of rotation, of the gantry unit 112 during scanning, e.g., the start position of the scan (i.e., the scan start control position), the intermediate control point of the scan, and / or the end position of the scan (i.e., the scan start control position). Alternatively or additionally, the rotation axis data may include, e.g., the position of the virtual rotation axis, i.e., the virtual center of rotation, of the gantry unit 112 during scanning, e.g., the start position of the scan, the intermediate control point of the scan, and / or the end position of the scan. The rotation angle data may include, e.g., the rotation angle of the gantry unit 112 during scanning, e.g., the start angle of the scan, the intermediate angle, and / or the end angle of the scan. The exposure parameter data may include, e.g., information regarding exposure parameters during the scan trajectory and / or at each ROI position. The sharp layer data may include, e.g., the size, shape, and position of the sharp layer. Portions of the patient's anatomy that fall under the sharp layer are sharp in dental x-ray imaging, while other portions of the patient's anatomy are blurred.The timing diagram data may include, for example, a timing diagram indicating when the X-ray beam is turned on and off for each specific ROI location. The dental atlas data 1116 may be generated from data retrieved from one or more dental atlas databases. The term "dental atlas" may also be referred to as a dental model, dental template, dental mold, dental sample, dental framework, dental artifact, dental prototype, and / or other similar terms. The dental atlas data 1116 may cover information not only about the dentition, but also about the mandible, maxilla, and / or skull, or portions thereof. Therefore, the "dental" prefix of the term "dental atlas data" may include synonyms such as at least jaw, dental arch, dental arch, mandible, maxilla, and / or maxillofacial region. The dental atlas data 1116 may be stored in the memory unit 1108 of the control system 106.

[0046] The at least one image analysis model 1118 may be formed based on previously collected reference image data. For example, the at least one image analysis model 1118 may be trained using previously collected reference image data. The at least one image analysis model 1118 may include at least one machine learning (ML)-based model and / or at least one artificial intelligence (AI)-based model. The at least one image analysis model 1118 may further include at least one conventional image analysis model, in some cases. The at least one ML-based model may be formed by applying one or more known ML techniques. According to non-limiting examples, the at least one ML-based model may be based on, for example, an ensemble of regression tree ML methods and / or a histogram of oriented gradients (HoG) ML method. The at least one AI-based model may be formed by applying one or more known AI techniques. According to non-limiting examples, the at least one AI-based model may be based on, for example, a deep neural network, a deep convolutional neural network, a conventional neural network, a region-based convolutional network, and / or a region-based fully convolutional network, etc. Previously collected reference image data for the at least one image analysis model may be collected, and the at least one image analysis model 1118 may be formed from the previously collected reference image data before the control system 106 implements the at least one image analysis model 1118 (e.g., in defining the ROI location). The at least one image analysis model 1118 may be stored in the memory portion 1108 of the control system 106.

[0047] The previously collected reference image data may include image data of a large number of people. By way of non-limiting example, the large number of people may include more than approximately 1,000 people. Preferably, the large number of people may include approximately 2,000 to 3,000 people or more. The reference image data may include at least one optical reference image of each person belonging to the plurality of large numbers of people. Preferably, the reference image data may be composed of multiple optical images of each person belonging to the plurality of large numbers of people. The multiple optical images of each person may include optical images from multiple different positions and / or angles of view of the person. For example, the multiple optical images of each person may include an optical image from the front of the person, optical images from each side of the person, an optical image from a head-down position, an optical image from a head-up position, and / or at least one optical image having a stern expression (i.e., an expression in which the person's dentition is at least partially, preferably fully, visible). The reference optical images of the reference image data may be still images and / or moving images. The reference image data may be captured using at least one reference imaging device 302. Preferably, the reference image data may be captured using multiple reference imaging devices 302. This allows multiple optical images to be captured substantially simultaneously from different angles of view. At least one reference imaging device 302 may be a 2D imaging device and / or a 3D imaging device. Preferably, at least one reference imaging device 302 is a 3D imaging device. The descriptions regarding the 3D imaging device and the 2D imaging device described above with reference to the at least one imaging device 104a, 104b also apply to the at least one reference imaging device 302.

[0048] According to a non-limiting example, the reference image data may be provided from one or more reference imaging locations, e.g., one or more photo booths 300. Each reference image location 300 may include multiple reference imaging devices 302 configured to provide at least a portion of the reference image data. FIG. 3 illustrates a non-limiting example of a reference imaging location, e.g., a photo booth 300, including multiple reference imaging devices 302 configured to provide at least a portion of the reference image data. In the example of FIG. 3, the multiple reference imaging devices 302 are arranged in a stereoscopic configuration. Accordingly, reference numeral 302 refers to a pair of reference imaging devices. In the example of FIG. 3, a person 304 is photographed within the photo booth 300, and the multiple reference imaging devices 302 are configured to capture reference optical images of the person 304, which may be included in the reference image data.

[0049] According to one embodiment, the at least one image analysis model 1118 may be further retrained at a later time, for example, using additional reference image data collected during use of the method by the dental x-ray imaging system 100. For example, optical images 105 of the patient 600 captured by the at least one optical imaging device 104a, 104b may be used as additional reference image data for further retraining the at least one image analysis mode. Alternatively or additionally, the additional reference image data may be collected using the at least one reference imaging device 302, for example, in one or more photo booths 300. The retrained at least one image analysis model 1118 may be stored in the memory 1108 of the control system 106, replacing the previously stored at least one image analysis model 1118.

[0050] As described above, in step 230, the control system 106 defines an ROI location based on the ROI data, at least one optical image 105, dental atlas data 1116, and at least one image analysis model 1118. To define the ROI location, the control system 106 may first determine aligned dental atlas data for the patient 600 based on the at least one optical image 105, dental atlas data 1116, and at least one image analysis model 1118 of the patient 600. The aligned dental atlas data can include the dental atlas data 1116 aligned with the patient 600, e.g., atlas anatomical data aligned with the patient 600, and optionally at least a portion of the atlas imaging data aligned with the patient 600. When the dental atlas data 1116 is aligned with the patient 600, the atlas anatomical data and optionally at least a portion of the atlas image data can be transferred to the correct location and anatomical structure of the patient 600. After determining the aligned dental atlas data for the patient 600, the control system 106 is configured to define an ROI position based on the ROI data and the determined aligned dental atlas data for the patient 600. FIG. 4 schematically illustrates an example of a method for determining aligned dental atlas data for the patient 600 based on at least one optical image 105 of the patient 600, dental atlas data 1116, and at least one image analysis model 1118. The determined aligned dental atlas data for the patient 600 may be used in defining the ROI position in step 230. Alternatively or additionally, the determined aligned dental atlas data for the patient 600 may be used for one or more other applications, such as defining exposure parameters for a scan as described later in this application. Determining the aligned dental atlas data for the patient 600 requires at least one optical image 105 of the patient 600 in which the patient's 600 dentition is at least partially visible.In other words, the at least one optical image 105 of the patient 600 used in determining the registered dental atlas data consists of at least one optical image in which the dentition of the patient 600 is at least partially visible. Preferably, at least two optical images 105 of the patient 600, in which the dentition of the patient 600 is at least partially visible, taken from different angles of view, may be used, thereby allowing for better coverage of the head of the patient 600 in the optical images 105.

[0051] In step 410, the control system 106 may determine (e.g., extract) multiple head landmarks 502, 504, 506, 508, 510, 512 of the patient 600 based on the at least one optical image 105 of the patient 600 and the at least one image analysis model 1118. For example, the at least one image analysis model 1118 (e.g., at least one ML-based model) may be used to detect the multiple head landmarks 502, 504, 506, 508, 510, 512 from the at least one optical image 105 of the patient 600. In other words, the at least one optical image 105 of the patient 600 may be used as input data for the at least one image analysis model 1118, and the multiple head landmarks 502, 504, 506, 508, 510, 512 of the patient 600 may be obtained as output data of the at least one image analysis model 1118. The determined plurality of head landmarks 502, 504, 506, 508, 510, 512 may be presented as 3D coordinates. The determined plurality of head landmarks 502, 504, 506, 508, 510, 512 may include, for example, but are not limited to, a predefined number of maxillary anterior teeth (e.g., the three most central teeth on each side, i.e., canine to canine) landmarks 502, a predefined number of mandibular anterior teeth (e.g., the three most central teeth on each side) landmarks 512, a mandibular condyle landmark 504, a chin landmark 506, a chin notch landmark 508, and / or an acanthion, i.e., a nasal crossing landmark 510. Other non-limiting examples of head landmarks may include, but are not limited to, tragus landmark(s), ear canal landmark(s), sinus landmark(s), TMJ landmark(s), orbital landmark(s) (e.g., infraorbital landmark(s)), and / or landmarks of any other anatomically relevant structure. A predetermined number of maxillary anterior landmarks 502 are placed directly on the maxilla. Similarly, a predetermined number of mandibular anterior landmarks 512 are placed directly on the mandible.Other landmarks of the patient 600 (e.g., the mandibular condyle landmark 504, the chin landmark 506, the chin notch landmark 508, and / or the acanthion landmark 510) may be detected on the skin surface, and these landmarks may be projected onto the bone by projecting through the average skin-facial thickness, i.e., by shifting inward by the average skin-facial thickness. Alternatively or additionally, it is not necessary to determine both the maxillary anterior landmark 502 and the mandibular anterior landmark 512. For example, if the maxillary anterior landmark 502 is determined, the mandibular anterior landmark 512 may be determined by projecting the maxillary anterior landmark 502 downward on the bone by the length of the known teeth.

[0052] 5A and 5B schematically illustrate a non-limiting example of a plurality of head landmarks 502, 504, 506, 508, 510, 512 of a patient 600 determined based on at least one optical image 105 of the patient 600 and at least one image analysis model 1118. In this example, the plurality of head landmarks 502, 504, 506, 508, 510, 512 of the patient 600 include three maxillary anterior landmarks 502 on each side, a mandibular condyle landmark 504, a chin landmark 506, a mandibular notch landmark 508, and an acanthion landmark 510. FIG. 5A illustrates a non-limiting example maxillary model 520 onto which the maxillary landmarks of the determined head landmarks 502, 504, 506, 508, 510, 512 of the patient 600 are projected. In this example, the maxillary landmarks include three maxillary anterior landmarks 502 on each side and an acanthion landmark 510. The projection of the acanthion landmark 510 on the bone is indicated by an arrow in FIG. 5A, and the acanthion landmark detected on the skin surface is indicated by reference numeral 510'. FIG. 5B shows a non-limiting example mandibular model 530 onto which the mandibular landmarks of the patient 600 are projected, the determined multiple head landmarks 504, 506, 508, 510, 512. In this example, the mandibular landmarks include three mandibular anterior landmarks 512 on each side, a condylar landmark 504, a chin landmark 506, and a mandibular notch landmark 508. The projections of the mandibular condyle landmark 504, the chin landmark 506, and the chin notch landmark 508 onto the bone are indicated by arrows in Figure 5B, and the mandibular condyle landmark, chin landmark, and chin notch landmark detected on the skin surface are indicated by reference numerals 504', 506', and 508', respectively. Also, the projection of the maxillary anterior landmark 502 onto the bone to determine the mandibular anterior landmark 512 is indicated by an arrow in Figure 5B.

[0053] According to one embodiment, the control system 106 may further estimate the reliability of the patient 600's landmarks extracted in step 410 and / or in other steps described later in this application. The reliability estimation of the patient 600's landmarks is illustrated in the example of FIG. 4 as optional step 412. The reliability estimation can be, for example, binarized and / or weighted. In binary reliability estimation, the landmarks are divided into two groups: 1) valid landmarks (used for registration in step 430) and 2) invalid landmarks (not used for registration in step 430). Registration in step 430 is described below. In weighted reliability estimation, each landmark receives a weight reflecting its estimated reliability. A higher reliability corresponds to a higher weight, and a lower reliability corresponds to a lower weight. Weighted reliability estimation may assume that the registration process in step 430 processes the weights. Alternatively, binary labeling and invalid landmark removal may be used. Typically, the at least one image analysis model 1118 can output all landmarks even when there is an occlusion (e.g., when the lips obstruct the visibility of a particular tooth (e.g., a canine)), when a target structure is missing (e.g., when the patient 600 does not have a particular tooth (e.g., a canine)), and / or when the landmark is misaligned (e.g., when a detected canine landmark corresponds to the location of a premolar). Such landmarks are invalid and should not be used in the registration process of step 430. Similarly, in the weighted confidence estimation, these invalid landmarks should be assigned a zero weight or at least a very small weight. The control system 106 may, for example, use spatial analysis for the confidence estimation. The relative distance between any two landmark points (taking into account scaling differences between different heads) is approximately known in advance. Similarly, the relative angle between two lines is also approximately known in advance. For example, the line connecting the landmarks associated with the tragus and the infraorbital region and the line connecting the landmarks associated with the tragus and the acanthion 510 are known to have a relative angle close to 10 degrees.A large deviation from the expected relative distance and / or relative angle indicates low confidence. Alternatively or additionally, the control system 106 may use, for example, region content analysis for confidence estimation. In region content analysis, the control system 106 analyzes the content of at least one optical image 105 near the detected landmark. The region content analysis may be, for example, texture region analysis, color texture region analysis, and / or other region analysis. The region analysis may also be based on an AI model trained to perform landmark confidence estimation. Alternatively or additionally, if the at least one imaging device 104a, 104b captures optical images at different times, the control system 106 may use temporal analysis for confidence estimation. When the patient 600 is supported by the patient supports 124, 126, it is assumed that the anatomical structures of interest have substantially stable spatial positions over a short time interval. If the positions of landmarks change significantly over a short time interval, it is assumed that the confidence is low. Similarly, if the landmarks remain stable, a high confidence can be assumed.

[0054] According to another embodiment, the control system 106 may alternatively or additionally combine landmarks of the patient 600 at the same anatomical location and / or combine spatial information, i.e., combine landmarks detected from optical images obtained from multiple imagers 104a, 104b. Combining landmarks of the patient 600 is illustrated as optional step 414 in the example of FIG. 4. According to one embodiment, when multiple imagers 104a, 104b are used, there may be multiple detected landmarks for the same anatomical location as seen by different imagers and / or multiple landmark detections taken at slightly different times (multiple temporal locations). As a result, there may be multiple landmarks at the same anatomical location. Any of a number of strategies may be used to combine multiple instances of the same landmark into a single landmark. For example, a weighted averaging scheme may be used. Some non-limiting exemplary averaging schemes include, for example, fixed weighting (e.g., arithmetic averaging), weighting according to time (e.g., giving more recent time points more weight than older samples, i.e., temporal averaging), and / or weighting according to confidence. This landmark combination is optional, and the necessity of combining may depend on the registration process in step 430. For example, if the registration process can handle unevenly spaced point sets (e.g., an iterative closest point (ICP) algorithm), more than one landmark may be maintained per anatomical location. According to another embodiment, when multiple imagers 104b are used, some landmarks may be visible and detected in optical images from one imager 104a, 104b, and other landmarks may be visible and detected in other optical images from the other imagers 104a, 104b. The detected landmarks may be represented in an imager internal coordinate system specific to each imager 104a, 104b. Combining spatial information refers to transforming the landmarks from different imager coordinate systems into one base coordinate system.One possibility is to assign one imaging device 104a, 104b as the master imaging device and transfer landmarks detected in the optical images of the other (i.e., slave) imaging device 104a, 104b. The transformation between the imaging devices 104a, 104b can be known from a joint calibration of the imaging devices 104a, 104b. Another option is to agree on another fixed coordinate system, for example, the coordinate system of the dental X-ray imaging unit 102, as the base coordinate system and transform the landmarks determined from the optical images of each imaging device 104a, 104b into the coordinate system of the dental X-ray imaging unit 102. The transformation from imaging device coordinates to the coordinates of the dental X-ray imaging unit 102 can be known based on calibration data formed by calibrating the imaging devices 104a, 104b to the dental X-ray imaging unit 102. The calibration can be performed, for example, during setup of the dental X-ray imaging unit 102. The calibration may also be repeated after any period of time, for example, during annual maintenance. The calibration may use a calibration target consisting of at least three calibration marks visible in optical and x-ray images.

[0055] According to one embodiment, if the control system 106 cannot determine one or more of the plurality of head landmarks 504, 506, 508, 510, 512 of the patient 600 based on the at least one optical image 105 of the patient 600 and the at least one image analysis model 1118, the control system 106 can generate instructions for an operator of the dental x-ray imaging unit 102 via one or more user interface devices, for example, user interface device 140a. In response to the generated instructions for the operator, the operator can manually input one or more missing head landmarks of the patient 600 (e.g., one or more of the plurality of head landmarks 502, 504, 506, 508, 510 of the patient 600 that the control system 106 cannot determine) via one or more user interface devices, for example, user interface device 140a. The minimum amount of landmarks of the patient 600 used for registration in step 430 may be, for example, three. Preferably, the patient's 600 landmarks used for registration in step 430 may be sampled from different parts of the patient 600 and not all identify locations within the same region. For example, three landmarks located on all of the patient's 600 anterior teeth may not be sufficient to provide accurate registration across the entire modeled region. For example, after estimating the reliability of the patient's 600 determined landmarks in optional step 412, if there are fewer than three reliable landmarks and / or if there are no reliable landmarks outside the central tooth region, the control system 106 may generate instructions to the operator of the dental x-ray imaging unit 102 to manually input one or more missing cranial landmarks for the patient 600 via one or more user interface devices.

[0056] In step 420, the control system 106 may select atlas landmarks included in the dental atlas data 1116. For example, the selected atlas landmarks may correspond to the head landmarks 502, 504, 506, 508, 510, and 512 of the patient 600 determined in step 410 described above. In other words, the number of head landmarks 502, 504, 506, 508, 510, and 512 of the patient 600 is the same as the number of atlas landmarks. This enables point-based pairwise registration in step 430. In the pairwise registration of each head landmark 502, 504, 506, 508, 510, and 512 of the patient 600, there is exactly one atlas landmark corresponding to the same anatomical location. As described above, at least some of the detected head landmarks 502, 504, 506, 508, 510, and 512 of the patient 600 may be labeled as invalid landmarks and removed. In this case, the control system 106 can select only corresponding landmarks from the valid landmarks in the dental atlas data 1116. Although step 410 is placed before step 420 in FIG. 4, step 420 may be performed before step 410 or simultaneously with step 410. That is, the control system 106 may first select multiple atlas landmarks included in the dental atlas data 1116. Next, the control system 106 may determine multiple head landmarks 502, 504, 506, 508, 510, 512 of the patient 600, which correspond to the selected multiple atlas landmarks.

[0057] In step 430, the control system 106 may register (i.e., align) the plurality of atlas landmarks with the plurality of head landmarks 502, 504, 506, 508, 510, 512 of the patient 600 to determine aligned dental atlas data for the patient 600, i.e., the atlas anatomical data of the dental atlas data 1116 is aligned with the patient 600. The control system 106 may, for example, perform a point-based pairwise registration transformation between the plurality of head landmarks 502, 504, 506, 508, 510, 512 of the patient 600 and the plurality of corresponding atlas landmarks. Alternatively, the point-based registration transformation may be performed without pairing. The aligned dental atlas data for the patient 600 may include, for example, a patient-specific anatomical model that restates an estimate of the patient 600's anatomy. As already described above, the aligned dental atlas data may include at least atlas anatomical data aligned with the patient 600. For example, the registered dental atlas data may include estimated locations of anatomical structures of the patient 600, such as one or more single teeth, tooth ranges, dental arches (upper and / or lower), TMJ(s), condyle(s), chin, maxillary notch, acanthion, tragus(s), ear canal(s), sinus(s), orbit(s), and / or any other anatomically relevant structures. The control system 106 may further register the atlas imaging data with the patient 600 in step 430. Thus, the registered dental atlas data of the patient 600 may further include atlas imaging data registered with the patient 600. For example, the control system 106 may further define one or more possible ROI locations in the anatomical model of the patient 600 based on the atlas ROI data included in the dental atlas data 116. Thus, the determined, registered dental atlas data may further include one or more possible ROI locations in the anatomical model of the patient 600.Alternatively or additionally, in the case of panoramic imaging, in step 430, the control system 106 may further define initial scan trajectory data based on the atlas scan trajectory data included in the dental atlas data 1116. Thus, the determined, registered dental atlas data for the patient 600 may further include the defined initial scan trajectory data.

[0058] The dental atlas data 1116 and the patient's 600 head landmarks 502, 504, 506, 508, 510, and 512 may be presented in different coordinate systems. For example, the atlas landmarks, atlas ROI data, and / or atlas scan trajectory data included in the dental atlas data 1116 may be presented in an atlas coordinate system. The patient's 600 head landmarks may be presented in an imaging device coordinate system, such as the imaging device coordinate system of a single imaging device, a base coordinate system (e.g., the master imaging device coordinate system or the coordinate system of the dental x-ray imaging unit 102 described above), or other known coordinate systems. The atlas coordinates and imaging device coordinates may be 2D, 3D, and / or 4D coordinates. Preferably, the atlas coordinates and imaging device coordinates are 3D coordinates. In other words, in step 430, the control system 106 can use a registration transformation to register the dental atlas data 1116 presented in the atlas coordinate system to the imaging device coordinate system. The registration transformation may be any type of transformation, such as, but not limited to, a rigid transformation, a rigid transformation with isotropic scaling, a rigid transformation with anisotropic scaling, an affine transformation, a perspective transformation, or any other linear transformation, or any nonlinear or deformable transformation. Furthermore, regularization terms may be used in some transformations, if necessary, to constrain the transformation to a physically more likely solution. Analytical solutions exist in certain special cases (e.g., paired point-based registration with a specific transformation). Otherwise, iterative minimization may be used. Any minimization algorithm may be used in iterative minimization. Registration may be defined as a minimization problem in which a cost function is minimized. For example, if the registration problem is formulated as maximizing similarity, the similarity value can be inverted (using a minus sign) to formulate the minimization problem. It is preferable to use a transformation that minimizes the residual registration error. After registration, the residual registration error (e.g., the final distance between registered points) may be known. The residual registration error indicates the accuracy of the registration. For accurate registration, a small residual error is desirable, but a large total residual error or a large individual error at one point usually indicates an inaccurate registration result.Thus, the accuracy of the registration can be evaluated based on the residual registration error. According to one embodiment, if the residual registration error exceeds a threshold, the registration may be deemed too inaccurate, and the control system 106 may generate a request for assistance from the operator of the dental X-ray imaging unit 102 via one or more user interface devices, e.g., user interface device 140a, to manually input one or more landmarks of the patient 600. For example, the control system 106 may use the registration transformation in step 430 to define one or more possible ROI locations within the anatomical model included in the registered dental atlas data. For example, the control system 106 may transform one or more possible ROI locations indicated in the atlas ROI data into imaging device coordinates to define one or more possible ROI locations within the anatomical model included in the registered dental atlas data. After transforming the atlas ROI data, i.e., the one or more possible ROI locations, into imaging device coordinates, the one or more possible ROI locations are known in imaging device coordinates. Thus, one or more possible ROI locations within the anatomical model included in the registered dental atlas data are also known. For example, in the case of CT imaging, the control system 106 may transform one or more possible FOV locations indicated in the atlas ROI data into imaging device coordinates to define one or more possible FOV locations within the anatomical model of the patient 600 included in the registered dental atlas data. Alternatively or additionally, in the case of panoramic imaging, the control system 106 may further define initial scan trajectory data based on the atlas scan trajectory data using the registration transformation in step 430, e.g., the control system 106 may transform at least one scan trajectory indicated in the atlas scan trajectory data included in the dental atlas data 1116 into imaging device coordinates to define the initial scan trajectory data included in the registered dental atlas data.

[0059] As described above, after determining the registered dental atlas data of the patient 600, the control system 106 may define an ROI position based on the ROI data and the determined, registered dental atlas data of the patient 600 in step 230. The ROI data included in the scan request may indicate a target ROI. The target ROI corresponds to one possible ROI position in the registered dental atlas data included in the registered dental atlas data. Thus, the control system 106 can define the ROI position as one possible ROI position corresponding to the target ROI. For example, if the target ROI is a single tooth, the control system 106 can define the ROI position as the position of the single tooth in the anatomical model included in the registered dental atlas data. Because the ROI position is defined in the dental arch model included in the registered dental atlas data, the ROI position is presented in imaging device coordinates. For example, in the case of CT imaging, the control system 106 may define the FOV position as an FOV position in the anatomical model included in the registered dental atlas data corresponding to the target FOV indicated in the ROI data. In the case of CT imaging, defining the ROI position may further include defining a center point of the undefined ROI position, i.e., an ROI center, e.g., an FOV center. According to a non-limiting example, if the target ROI consists of a single structure, e.g., a single tooth, the control system 106 may define the ROI center as the center of the single structure. According to another non-limiting example, if the target ROI consists of multiple structures, e.g., tooth regions, the control system 106 may define the ROI center as the center of the multiple structures. Alternatively or additionally, in the case of CT imaging, the control system 106 may be further configured to adjust the size of the FOV based on the detected registered dental atlas data of the patient 600. In CT imaging, the FOV may preferably be cylindrical. Thus, adjusting the size of the FOV based on the determined, registered dental atlas data of the patient 600 may include adjusting the height and / or radius of the cylindrical FOV.Because the determined, registered dental atlas data of the patient 600 allows reliable estimation of the patient's 600 anatomical structures and determination of the FOV position, the size of the FOV can be reduced so that the target FOV indicated in the ROI data is still located within the reduced FOV. Reducing the FOV can reduce the radiation dose to the patient 600, reduce the amount of acquired x-ray image data, and ultimately speed up processing of the acquired x-ray image data. For example, in the case of panoramic imaging, the control system 106 can define the position of the imaging layer to correspond to the patient's 600 anatomical structures based on the ROI data and the determined, registered dental atlas data of the patient 600.

[0060] The dental atlas data 1116, along with the at least one optical image 105 and the at least one image analysis model 1118, may be used to determine one or more dental structures of the patient 600 located within the head of the patient 600, such as the registered dental atlas data for the patient 600 described above. The at least one optical image 105 and the at least one image analysis model 1118 (without the dental atlas data 1116) may be used to determine visible patient-related data including one or more visible structures of the patient 600. For example, the control system 106 may further determine the visible patient-related data based on the at least one optical image 105 and the at least one image analysis model 1118 of the patient 600. The visible patient-related data may include, for example, head size data of the patient 600, classification data of the patient 600, height data of the patient 600, and / or width data of the patient 600. Examples of uses of the visible patient-related data are described later in this application.

[0061] After defining the ROI position in step 230 as described above, the control system 106 may further define a scan trajectory for each component of the dental X-ray imaging unit 102 in step 240 based on the defined ROI position, imaging mode data, and patient positioning data. According to one embodiment, the defined ROI position may include patient positioning data. Because the ROI position is defined in step 230 using the registered dental atlas, the defined ROI position can be substantially more accurate than, for example, an estimate of the ROI position typically used in defining the scan trajectory. Defining the scan trajectory may include defining a start position of the scan trajectory (i.e., a start position of a component of the X-ray imaging unit 102 for scanning) and / or a motion path of the scan trajectory. The patient positioning data may include a patient positioning position, e.g., a position where the patient 600 is supported. The patient positioning data may be defined based on, for example, the patient supports 124, 126 of the dental X-ray imaging unit 102. By way of non-limiting example, the patient positioning position may be determined based on, for example, a bite block, e.g., a bite bar, positioned on the chin support 124. Alternatively, the patient positioning data may be determined based on, for example, optical image data collected by at least one internal optical imaging device 104b of the dental x-ray imaging unit 102. The patient positioning data allows the control system 106 to know the position of the head of the patient 600, e.g., the position at which the patient 600 is supported.

[0062] The motion path of the scan trajectory may depend on the imaging mode indicated in the imaging mode data. In the case of CT imaging, the motion path of the scan trajectory may be, for example, a circular path or a non-circular path, such as an elliptical path, centered on a rotation axis. The circular or non-circular path may be a full or partial rotation around the rotation axis. The rotation axis may be the mechanical rotation axis of the gantry unit 112 or a virtual rotation axis. The mechanical rotation axis of the gantry unit 112 may be oriented, i.e., aligned, to a defined ROI position, as described below. The virtual rotation axis may be obtained, for example, by moving the mechanical rotation axis of the gantry unit 112 along a circular path, in which case the virtual rotation axis may be formed at the center of the circular path. A non-circular rotation path may be generated, for example, by moving the gantry unit 112 along a motion path that deviates from a circular path, such as an elliptical path. Other techniques or alignments for the rotation axis may also be used, as will be recognized by those skilled in the art. In the case of panoramic imaging, the scan trajectory may be, for example, a substantially arcuate trajectory.

[0063] When the position of the head of the patient 600 is known based on the patient position data, the start position of the scan trajectory may be defined based on the defined ROI position. For example, in the case of symmetric CT imaging in which the motion path of the scan trajectory is a circular path, the start position of the scan trajectory may be the center of the ROI defined in step 230. According to another embodiment, in the case of offset CT imaging in which the motion path of the scan trajectory is a circular path, the start position of the scan trajectory may be offset from the center of the ROI defined in step 230 by a known amount in a known direction, i.e., a known offset vector. As described above, in the case of panoramic imaging, the determined, registered dental atlas data of the patient 600 may include initial scan trajectory data. In the case of panoramic imaging, the scan trajectory may be defined based on the initial scan trajectory data. According to one embodiment, a patient-specific scan trajectory may be defined based on the initial scan trajectory data. The patient-specific scan trajectory may include a start position of the patient-specific scan trajectory and a motion path of the patient-specific scan trajectory. In some cases, because the registration transformation may not be rigid, the patient-specific scanning trajectory may violate some basic conditions, such as the magnification factor not being constant across the entire dental arch. Therefore, the defined patient-specific scanning trajectory can be adjusted (i.e., modified) so that the basic conditions are not violated. The patient-specific scanning trajectory allows substantially the entire dental arch of the patient 600 to be exposed to the sharp layer. According to one embodiment, a predefined scanning trajectory may be selected based on initial scanning trajectory data. The initial scanning trajectory data may include multiple predefined scanning trajectories, each of which may include a starting position and a motion path for the predefined scanning trajectory. The predefined scanning trajectory that best fits the anatomical structure of the patient 600 may be selected from the multiple predefined scanning trajectories included in the initial scanning trajectory data, for example, based on the smallest residual registration error in the registration transformation. The selected predefined scanning trajectory may not be a perfect fit, but it is a good approximation to the patient 600.Therefore, even if the starting position of a predefined scanning trajectory is known, this does not necessarily mean that it is the optimal starting position. If an optimal fit cannot be achieved over the entire scanning trajectory, it may be preferable to adjust the starting position of the predefined scanning trajectory so that the optimal fit can be achieved near the anterior tooth region, since the sharp layer is narrowest in that region. In other words, the starting position of the predefined scanning trajectory may preferably be adjusted so that at least the anterior tooth region hits the sharp layer. Using a selected predefined scanning trajectory may at least provide the advantage that the scanning trajectory, timing diagram, etc. are known in advance and there are no technical or mechanical limitations for applying them.

[0064] The ROI position may be expressed in coordinates different from device coordinates (i.e., coordinates of the dental x-ray imaging unit 102). Therefore, the control system 106 can define coordinate transformation data for determining the defined ROI position in device coordinates, and therefore the starting position of the scan trajectory, in device coordinates. The coordinate transformation data can represent a transformation between coordinates in which the ROI position is expressed in device coordinates. For example, as described above, the ROI position defined in step 230 may be expressed in imaging device coordinates. The control system 106 may define coordinate transformation data representing a transformation between imaging device coordinates and device coordinates. The coordinate transformation data may include, for example, device axis orientation data in imaging device coordinates. The device axis orientation data in imaging device coordinates may include, for example, the Z-axis (e.g., up-down (IS) axis) orientation, the Y-axis (e.g., anterior-posterior (PA) axis) orientation, and the X-axis (e.g., left-right (LR) axis) orientation of the dental x-ray imaging unit 102 in imaging device coordinates. The coordinate transformation data may be defined device orientation encoding and / or device position encoding.

[0065] FIG. 6A shows an example of a method for defining coordinate transformation data using device-orientation encoding. This method may be performed by the dental X-ray imaging system 100 described above. In step 610, the control system 106 may acquire at least one optical image of the dental X-ray imaging unit 102. The at least one optical image of the dental X-ray imaging unit 102 may be acquired, for example, by at least one internal imaging device 104b of the dental X-ray imaging unit 102. For example, device-orientation encoding may be used when the at least one internal imaging device 104b through which the at least one optical image of the dental X-ray imaging unit 102 is acquired is disposed in the gantry portion 112 of the dental X-ray imaging unit 102. Preferably, in step 610, the control system 106 may acquire at least two optical images of the dental X-ray imaging unit 102. The at least two optical images may be acquired by the at least two internal imaging devices 104b of the dental X-ray imaging unit 102. The control system 106 may, for example, obtain the at least one optical image of the dental X-ray imaging unit 102 from the at least one internal imager 104b of the dental X-ray imaging unit 102. Alternatively, the control system 106 may obtain the at least one optical image of the dental X-ray imaging unit 102 from a database in which the at least one optical image of the dental X-ray imaging unit 102 captured using the at least one internal optical imager 104b is stored.

[0066] In step 620, the control system 106 can determine (i.e., extract) device orientation data from at least one optical image of the dental x-ray imaging unit 102 by detecting at least one device-coding mark disposed on the dental x-ray imaging unit 102. The device orientation data may be encoded in the at least one device-coding mark. The control system 106 may extract the device orientation data encoded in the detected at least one coding mark. The device orientation data may be encoded in the at least one device-coding mark by any geometric primitive, object, or pattern, for example, but not limited to, formed by a circle, a point, a cross, a line, a rectangle, and / or a triangle. The at least one device-coding mark may be dual-purpose or concealed. For example, a checkerboard pattern, a QR code, a company name and / or logo, a brand name and / or logo, or a device name and / or logo may also be used as a device-coding mark. The at least one device-coding mark may be a 2D coding mark located on a 2D plane or surface. A single 2D coding mark can explicitly encode two of the three axes of the dental X-ray imaging unit 102, while the encoding of the third axis is implicit, e.g., defined as the cross product of the two explicitly encoded axes. For explicit 2D encoding, at least two 2D coding marks that are not located in the same plane are required. Alternatively, at least one device coding mark can be a 3D coding mark. This single 3D coding mark can explicitly encode all three axes of the dental X-ray imaging unit 102. If only one optical image of the dental X-ray imaging unit 102 is available, the device coding mark must be a 3D device coding mark. This allows the orientation of all three axes of the dental X-ray imaging unit 102 to be defined using only one optical image of the dental X-ray imaging unit 102. Alternatively, the device orientation data can be determined from two differently oriented 2D device coding marks.This also allows the orientation of all three axes of the dental X-ray imaging unit 102 to be defined using only one optical image of the dental X-ray imaging unit 102 .

[0067] In step 630, the control system 106 may determine coordinate transformation data, i.e., X-axis orientation, Y-axis orientation, and Z-axis orientation, of the dental X-ray imaging unit 102 based on the device orientation data determined in step 620. According to one embodiment, the Z-axis orientation may be explicitly coded in at least one device-coded mark. According to another embodiment, at least one internal imaging device 104b from which at least one optical image data of the dental X-ray imaging unit is obtained may be fixed to the dental X-ray imaging unit 102 such that one side of the imaging sensor of the internal imaging device 104b is fully vertical, thus defining the Z-axis orientation of the dental X-ray imaging unit 102 in imaging device coordinates. According to yet another embodiment, the X-axis orientation and the Y-axis orientation are explicitly coded in at least one device-coded mark, and the Z-axis orientation may then be implicitly determined as the product of the X-axis orientation and the Y-axis orientation. Alternatively, the Z-axis and X-axis orientations may be explicitly encoded in at least one device-coded mark, and the Y-axis orientation may be implicitly determined as the product of the Z-axis and X-axis orientations. Alternatively, the Z-axis and Y-axis orientations may be explicitly encoded in at least one device-coded mark, and the X-axis orientation may be implicitly determined as the product of the Z-axis and Y-axis orientations.

[0068] 6B schematically illustrates a non-limiting example of one optical image 601 of the dental X-ray imaging unit 102 for extracting device orientation data and using the device orientation coding to determine coordinate transformation data for the dental X-ray imaging unit 102. In the example of FIG. 6B, the internal imaging device 104b from which the optical image 601 of the dental X-ray imaging unit 102 is obtained is located in the dental X-ray imaging unit 102 on the right side of the patient 600. Alternatively, the internal imaging device 104b from which the optical image 601 of the dental X-ray imaging unit 102 is obtained may also be located in the dental X-ray imaging unit 102 on the left side of the patient 600. In the example of FIG. 6B, one device-coding mark is located on the same side of the dental X-ray imaging unit 102 as the internal imaging device 104b from which the optical image 601 of the dental X-ray imaging unit 102 is obtained. The device-coding mark includes three dots 602, 603, and 604 located on the chin support 126 of the lower shelf 122 of the dental X-ray imaging unit 102. In the example of FIG. 6B, the X-axis and the Y-axis are explicitly coded in the device-coding mark. However, this is merely one non-limiting example for locating a device-coding mark on the dental X-ray imaging unit 102, and at least one device-coding mark can also be located on another portion of the dental X-ray imaging unit 102 that is rigidly attached to the upper shelf 110 of the dental X-ray imaging unit 102. The upper shelf 110 determines the device axis orientation. For example, if the upper shelf 110 does not rotate, at least one device-coding mark can be located relative to the lower shelf 112 of the dental X-ray imaging unit 102 (e.g., the chin support 126 as shown in the example of FIG. 6B), relative to the support post 103, or relative to the upper shelf 110. Alternatively, if the upper shelf 110 rotates, at least one device coding mark must be placed on the upper shelf 110 or any structure attached to the upper shelf 110. The coding marks, including these dots, can be detected from the optical image 601. A first unit vector 605 connecting the coding mark dots 602 and 603 can define the Y-axis orientation of the dental X-ray imaging unit 102 in imager coordinates. A second unit vector 606 connecting the coding mark dots 603 and 604 can define the Z-axis orientation of the dental X-ray imaging unit 102 in imager coordinates.The X-axis orientation can be determined, for example, as the product of the Z-axis and the Y-axis.

[0069] 6C is a schematic diagram illustrating a non-limiting example of two optical images 601a, 601b of the dental X-ray imaging unit 102 for extracting device orientation data and determining coordinate transformation data for the dental X-ray imaging unit 102 using the device orientation coding. In the example of FIG. 6C, the first internal imaging device 104b that obtains the optical image 106a is located in the dental X-ray imaging unit 102 on the right side of the patient 600, and the second internal imaging device 104b that obtains the optical image 601b is located in the dental X-ray imaging unit 102 on the left side of the patient 600. In the example of FIG. 6C, two device-coding marks are located in the dental X-ray imaging unit 102, so one device-coding mark is located on each side of the dental X-ray imaging unit 102. The device-coding mark on the right side includes three dots 602R, 603R, and 604R that are located on the chin support 126 of the lower shelf 122 of the dental X-ray imaging unit 102. Additionally, the left-side device coding mark includes three dots 602L, 603L, and 604L arranged on the chin support portion 126 of the lower shelf 122 of the dental X-ray imaging unit 102. The coding mark including these dots can be detected from the two optical images 601a and 601b. A first right-hand unit vector 605R connecting the dots 602R and 603R of the right-hand coding mark can define the Y-axis orientation of the dental X-ray imaging unit 102 in the imaging device coordinate system. A second right-hand unit vector 606R connecting the dots 603R and 604R of the right-hand coding mark can define the Z-axis orientation of the dental X-ray imaging unit 102 in the imaging device coordinate system. A first left-hand unit vector 605L connecting the dots 602L and 603L of the left-hand coding mark can define the Y-axis orientation of the dental X-ray imaging unit 102 in the imaging device coordinate system. A second left unit vector 606L connecting the dots 603L and 604L of the left coding mark can define the Z-axis orientation of the dental x-ray imaging unit 102 in imaging device coordinates. The X-axis orientation can be determined by combining information from both coding marks, for example, by connecting the same dots on the left and right to form a line parallel to the X-axis. In this way, using two optical images to extract device orientation data allows for the extraction of the maximum amount of data.Furthermore, by extracting device orientation data using two optical images, the orientation of all three axes (X-axis, Y-axis, and Z-axis) can be explicitly defined.

[0070] In device position coding, the control system 106 can acquire at least one optical image of the dental X-ray imaging unit 102. The at least one optical image of the dental X-ray imaging unit 102 may be captured, for example, by at least one internal imaging device 104b of the dental X-ray imaging unit 102. Device position coding is used, for example, when the at least one internal imaging device 104b from which the at least one optical image of the dental X-ray imaging unit 102 is obtained is located in any portion of the dental X-ray imaging unit 102 that is rigidly attached to the top shelf 110 of the dental X-ray imaging unit 102. In device position coding, at least one device position and orientation coding mark may be located on the gantry portion 112 of the dental X-ray imaging unit 102. The at least one device position coding mark may encode at least one gantry point (defined herein as the gantry origin) and at least a horizontal gantry axis (e.g., the X-axis of the gantry portion 112 or the Y-axis of the gantry portion 112). The above description of the at least one device orientation coding mark also applies to the at least one device position coding mark. A vertical gantry axis (e.g., the Z axis of the gantry portion 112) may be defined from the orientation of the imaging device or may be coded in the device position coding mark. After defining the vertical and horizontal axes, another horizontal axis may be defined as the product of the defined vertical axis and the defined horizontal axis. The defined axes of the gantry portion 112 may define a gantry-specific coordinate system. The position of the center of rotation of the gantry portion 112 in the gantry coordinate system may be defined by calibration. Any movement of the dental x-ray imaging unit 102 does not change the position of the center of rotation of the gantry portion 112 relative to the gantry coordinate system. If at least one internal imaging device 104b from which at least one optical image of the dental X-ray imaging unit 102 is obtained is located in a part of the dental X-ray imaging unit 102 other than the gantry portion 112 and the part rigidly attached to the upper shelf 110 of the dental X-ray imaging unit 102 (e.g., within the support 103), a combination of device orientation encoding and device position encoding may be used to define the coordinate transformation data.Alternatively or additionally, if at least one optical image of the dental X-ray imaging unit 102 is obtained from at least one external imaging device 104a, a combination of device orientation encoding and device position encoding may be used to define the coordinate transformation data.

[0071] After defining the scan trajectory in step 240 as described above, the control system 106 may further control each component of the dental X-ray imaging unit 102 in step 250 to scan the patient 600 according to the defined scan trajectory to acquire dental X-ray image data of the patient 600. The control system 106 may define a current position of the rotation axis of the gantry portion 112 based on calibration data of the at least one imaging device 104 a, 104 b for the dental X-ray imaging unit 102. The control system 106 may define machine transformation data to control the gantry portion 112 of the dental X-ray imaging unit 102 to move from the current position of the rotation axis of the gantry portion 112 to a start position of the scan trajectory. The machine transformation data may indicate a transformation of machine coordinates required to move the rotation axis of the gantry portion 112 from the current position to the start position. The control system 106 may be configured to control components of the dental X-ray imaging unit 102 to move to a start position of the scan trajectory (i.e., a specified ROI position) based on the unspecified device transformation data. The movement of each part of the dental X-ray imaging unit 102, for example, the gantry part 112, may be linear and / or rotational. As a result, the rotation axis of the gantry part 112 is moved to the specified start position of the scan trajectory. The control system 106 may then control the gantry part 112 to rotate according to the specified motion path of the scan trajectory around the rotation axis of the gantry part 112.

[0072] 7A and 7B show non-limiting examples of movement of the gantry unit 112 from the current position of the rotation axis of the gantry unit 112 to the start position of the scan trajectory based on the device transformation data in the case of CT imaging. FIG. 7A shows a situation in which the rotation axis of the gantry unit 112 is at the current position (i.e., before control of the movement of the gantry unit 112). The current position of the rotation axis of the gantry unit 112 is illustrated by reference numeral 702, and the start position of the scan trajectory is illustrated by reference numeral 704. In this example, the device transformation data consists of an X-direction translation illustrated by vector 706 and a Y-direction translation illustrated by vector 708. FIG. 7B shows a situation after control of the movement of the gantry unit 112 from the current position 702 of the rotation axis of the gantry unit 112 to the start position 704 of the scan trajectory. In other words, in the situation of FIG. 7B, the rotation axis of the gantry unit 112 is positioned at the start position of the scan trajectory 704. For example, in CT imaging where the motion path is a cylindrical path, the rotation axis of the gantry unit 112 is positioned at the defined FOV, i.e., the rotation axis of the gantry unit 112 is parallel to the center of the defined FOV. According to another embodiment, in CT imaging with offset scanning, the rotation axis of the gantry unit 112 is slightly offset from the center of the defined FOV, and the gantry unit 112 may move across the FOV during the scan. Thus, in offset scanning, the starting position of the scan trajectory 704 is offset from the center of the defined FOV.

[0073] 7C and 7D show non-limiting examples of movement of the gantry unit 112 from the current position of the rotation axis of the gantry unit 112 to the start position of the scan trajectory based on the device transformation data in the case of panoramic imaging. FIG. 7C shows a situation in which the rotation axis of the gantry unit 112 is at the current position (i.e., before control of the movement of the gantry unit 112). The current position of the rotation axis of the gantry unit 112 is indicated by reference numeral 710, and the start position of the scan trajectory is indicated by reference numeral 712. In this example, the device transformation data consists of an X-direction translation illustrated by vector 714 and a Y-direction translation illustrated by vector 716. FIG. 7D shows a situation after control of the movement of the gantry unit 112 from the current position 710 of the rotation axis of the gantry unit 112 to the start position 712 of the scan trajectory. In other words, in the situation of FIG. 7D, the rotation axis of the gantry unit 112 is positioned at the start position of the scan trajectory 712. In the embodiment of FIG. 7D , an example of the motion path of the scanning trajectory relative to the mechanical rotation axis, i.e., the mechanical center of rotation, of the gantry section 112 in panoramic imaging is further indicated by reference numeral 718. The scanning trajectory motion path 718 begins at a scanning trajectory start position 712. The middle of the scanning trajectory motion path 718 is indicated by point 720, the end of the scanning trajectory motion path 718 is indicated by point 720, and the end of the scanning trajectory motion path 718 is indicated by point 722. Furthermore, since the gantry section 112 rotates according to the scanning trajectory's prescribed motion path 718 around the mechanical rotation axis of the gantry section 112, a virtual rotation axis of the gantry section 112 is also formed. In the embodiment of FIG. 7D , the motion path of the virtual rotation axis of the gantry section 112 is further indicated by reference numeral 724. The start position of the motion path 724 of the virtual rotation axis of the gantry section 112 is indicated by point 726. The middle of the motion path 724 of the imaginary axis of rotation of the gantry section 112 is indicated by point 728 and the end of the motion path 724 of the imaginary axis of rotation of the gantry section 112 is indicated by point 730 .

[0074] According to one embodiment, the control system 106 can alternatively or additionally determine exposure (i.e., radiation) parameters for a scan of the patient 600 based on the imaging mode data, at least one optical image 105 of the patient, and at least one image analysis model 1118. The exposure parameters may include, but are not limited to, radiation output, radiation dose, and / or radiation time, etc. To determine the exposure parameters, the control system 106 may first determine head size data of the patient 600 based on the at least one optical image 105 of the patient 600 and the at least one image analysis model 1118. The control system 106 may then use the determined head size data and imaging mode data of the patient 600 in determining the exposure parameters. FIG. 8A schematically illustrates one embodiment of a method for determining exposure parameters for a scan of the patient 600.

[0075] In step 810, the control system 106 may determine a plurality of head landmarks of the patient 600 based on at least one optical image of the patient 600 and at least one image analysis model. The plurality of head landmarks of the patient 600 may, for example, correspond at least in part to the head landmarks 502, 504, 506, 508, and 510 of the patient 600 defined with reference to step 410 described above. Alternatively or additionally, the plurality of head landmarks of the patient 600 may include any other head landmarks 802 of the patient 600. FIG. 8B schematically illustrates an example of a plurality of head landmarks 802 of the patient 600 that may be determined to define head size data of the patient 600. Although FIG. 8B illustrates only one side of the patient's 600's head and therefore also illustrates a plurality of head landmarks 802 of the patient 600 on one side of the patient's 600's head, corresponding head landmarks 802 of the patient 600 may also be determined on the other side of the patient's 600's head. For example, at least one image analysis model 1118 (e.g., at least one ML-based model) may be used to detect multiple head landmarks 802 of the patient 600 from at least one optical image 105 of the patient 600. In other words, the at least one optical image 105 of the patient 600 may be used as input data for the at least one image analysis model 1118, and the multiple head landmarks 802 of the patient 600 may be obtained as output data of the at least one image analysis model 1118.

[0076] In step 820, the control system 106 may determine head size data for the patient 600 based on the plurality of head landmarks 802 for the patient 600 determined in step 810. The head size data may include, for example, an estimate of the head size of the patient 600. Determining the head size data for the patient 600 may further include the use of anthropometric scales. The anthropometric measurements may reveal population statistics. For example, the head size may be larger than 90% of individuals in the population (e.g., adult males). The plurality of head landmarks 802 for the patient 600 may also include points used in anthropometry (e.g., nostrils, corners of the eyes, tragus, chin, and / or any points that can be used in anthropometric measurements). The size of the head determines the amount of tissue. The more tissue there is, the higher the exposure required.

[0077] In step 830, the control system 106 may use the head size data of the patient 600 determined in step 820 in determining the exposure parameters. For example, the head size data of the patient 600 can be used to select values ​​for the exposure parameters. In addition to head size, the values ​​for the exposure parameters may depend on the imaging mode. As described above, the imaging mode is indicated in the imaging mode data. The exposure parameters may be based, for example, on tabulated values. These tabulated values ​​may include tabled parameters based on the imaging mode and / or head size. There may be only one population (i.e., only head size is important). Additionally, there may be different tables for different populations by age and / or gender. In that case, classification data may be used to select the correct population table. Determining the classification data for the patient 600 is described later in this application. In addition to tabulated values, the exposure parameters may be determined by equations based on the head size data and, optionally, the classification data. Also, different equations may exist for different populations, and the correct equation may be selected based on the patient's classification data. After determining the exposure parameters, control system 106 may provide the determined exposure parameters via one or more user interface devices, such as user interface device 140a, for operator review and approval.

[0078] According to one embodiment, the control system 106 further determines classification data for the patient 600 and may also use the classification data in determining the exposure parameters in step 830. The control system 106 may determine the classification data for the patient 600 based on at least one optical image 105 of the patient 600 and at least one image analysis model 118. The classification data may include, for example, an estimate of the age of the patient 600 and / or an estimate of the gender of the patient 600. In other words, the control system 106 may estimate the age of the patient 600 and / or the gender of the patient 600 from the at least one optical image 105 of the patient 600 using at least one image analysis model 118, e.g., at least one AI-based model. The age estimate of the patient 600 may be an estimate of an age category, such as child, teenager, adult, elderly, etc. This optional step of determining classification data for the patient 600 is illustrated in the example of FIG. 8A as optional step 840. Although step 820 is shown before step 840 in FIG. 8A, optional step 840 may be performed before or simultaneously with step 820.

[0079] According to another embodiment, the control system 106 may alternatively or additionally use aligned dental atlas data for the patient 600 in determining the exposure parameters. The aligned dental atlas data for the patient 600 may be defined, for example, as described above with reference to method steps 410-430 of FIG. 4. This optional step of determining aligned dental atlas data for the patient 600 is illustrated as optional step 850 in the example of FIG. 8A. Although steps 820 and 830 are illustrated before step 850 in FIG. 8A, each of steps 820, 830, and 840 may also be performed in any other order or simultaneously.

[0080] According to yet another embodiment, the control system 106 may alternatively or additionally adjust the height of components of the dental X-ray imaging unit 102 based on at least one optical image 105 of the patient 600 and at least one image analysis model 1118. The height of the components of the dental X-ray imaging unit 102 may be adjusted by moving the carriage 101 up and down in the height direction Z along the support column 103 using a guide motor. To adjust the height of the components of the dental X-ray imaging unit 102, the control system 106 may first determine height data of the patient 600 based on the at least one optical image 105 of the patient 600 and the at least one image analysis model 1118. The control system 106 may then adjust the height of the components of the dental X-ray imaging unit 102 using the determined height data of the patient 600. FIG. 9A schematically illustrates one embodiment of a method for adjusting the height of components of the dental X-ray imaging unit 102.

[0081] In step 910, the control system 106 may determine at least one head landmark of the patient 600 based on at least one optical image of the patient 600 and at least one image analysis model. At least one of the head landmarks of the patient 600 may be one of the head landmarks 502, 504, 506, 508, 510, 512, 802 of the patient 600 defined with reference to step 410 and / or step 810 described above. Alternatively or additionally, at least one of the head landmarks of the patient 600 may be at least one other head landmark of the patient 600. For example, the at least one head landmark of the patient 600 may be the chin 506 of the patient 600. For example, at least one image analysis model 1118 (e.g., at least one ML-based model) may be used to detect at least one head landmark of the patient 600 from the at least one optical image 105 of the patient 600. In other words, at least one optical image 105 of the patient 600 may be used as input data for at least one image analysis model 1118, and at least one head landmark of the patient 600, for example, the chin 506 of the patient 600, may be obtained as output data for the at least one image analysis model 1118.

[0082] In step 920, the control system 106 may determine height data of the patient 600 based on the at least one head landmark of the patient 600 determined in step 910. The height data may be, for example, a height offset value (h) between the at least one head landmark of the patient 600 and at least one reference height point in the dental X-ray imaging unit 102. off), and / or the absolute distance between at least one head landmark of the patient 600 and the floor. The at least one reference height point in the dental X-ray imaging unit 102 may include, for example, the top surface of the chin support 124. For example, to define a height offset value between at least one head landmark of the patient 600 and the at least one reference height point in the dental X-ray imaging unit 102, it may be necessary to know the position of the optical imaging device configured to capture the at least one optical image 105 used in this example relative to the at least one reference height point in the dental X-ray imaging unit 102. FIG. 9B illustrates a height offset value (h ) between at least one head landmark of the patient 600 (e.g., the chin 506 of the patient 600 in this example) and at least one reference height point in the dental X-ray imaging unit 102 (e.g., the top of the chin support 124 in this example). off 1 shows a schematic diagram of an embodiment of a

[0083] In step 930, the control system 106 may adjust the height of the components of the dental X-ray imaging unit 102 based on the height data of the patient 600 determined in step 920. The possible adjustment directions (up and down) of the height of the components of the dental X-ray imaging unit 102 are indicated by arrows 910 in the example of Figure 9B.

[0084] According to yet another embodiment, the control system 106 may alternatively or additionally reduce a collision risk between the patient 600 and the gantry portion 112 of the dental X-ray imaging unit 102 based on at least one optical image 105 of the patient 600 and at least one image analysis model 1118, such as at least one ML-based model. To reduce the collision risk, the control system 106 may first determine width data of the patient 600 based on the at least one optical image 105 of the patient 600 and the at least one image analysis model 1118. The control system 106 may then use the determined width data of the patient 600 when reducing the collision risk. FIG. 10A schematically illustrates one embodiment of a method for reducing a collision risk between the patient 600 and the gantry portion 112 of the dental X-ray imaging unit 102.

[0085] In step 1010, the control system 106 can determine multiple body landmarks 1002 of the patient 600 based on at least one optical image 105 of the patient 600 and at least one image analysis model 1118. The multiple body landmarks 1002 may include, for example, the shoulders of the patient 600. For example, the at least one image analysis model 1118 (e.g., at least one ML-based model) may be used to detect the shoulders of the patient 600 from the at least one optical image 105 of the patient 600. In other words, the at least one optical image 105 of the patient 600 may be used as input data for the at least one image analysis model 1118, and the multiple body landmarks 1002 of the patient 600, for example, the shoulders of the patient 600, may be obtained as output data of the at least one image analysis model. FIG. 10B schematically illustrates an example of multiple body landmarks 1002 of the patient 600 (e.g., the shoulders of the patient 600) that can be determined to define width data of the patient 600. Alternatively, in step 1010 , the control system 106 may determine extremum points on the body of the patient 600 , for example, on the shoulders of the patient 600 , from at least one optical image 105 of the patient 600 .

[0086] In step 1020, the control system 106 may determine width data for the patient 600 based on the patient's 600 body landmarks 1002 or the extreme points of the patient's 600 body determined in step 1010. The width data may include, for example, the width of the patient 600, e.g., the distance between the patient's 600 body landmarks 1002, e.g., the distance between the patient's 600 shoulders. In the example of FIG. 10B, the distance (w) between the patient's 600 shoulders 1002 is illustrated.

[0087] In step 1030, the control system 106 uses the patient width data determined in step 1020 to reduce the risk of collision between the patient 600 and the gantry portion 112 of the dental X-ray imaging unit 102. For example, the control system 106 may use the determined width data of the patient 600 in guiding the patient 600 and / or the operator of the dental X-ray imaging unit 102 during the patient's 600 entry into the dental X-ray imaging unit 102 via one or more user interface devices, e.g., a display device and / or a speaker device. The one or more user interface devices may include the user interface device 140a and / or one or more other user interface devices. For example, the guidance may include guidance on a suitable grip the patient 600 should take on the handle portion 128 of the dental X-ray imaging unit 102. The determined width data may be used to select an appropriate grip to reduce the risk of collision between the patient 600 and the gantry portion 112 of the dental X-ray imaging unit 102.

[0088] According to yet another embodiment, the control system 106 can alternatively or additionally generate patient position correction data for patient positioning. The patient position correction data may be generated based on at least one optical image 105 of the patient 600 and at least one image analysis model 1118. In this embodiment, the at least one optical image 105 of the patient 600 may be captured by at least one internal imaging device 104b, for example, during patient positioning. For example, the patient 600 may first be positioned by at least one of the patient supports 124, 126, for example, and then at least one optical image 105 of the patient 600 may be captured to generate the patient position correction data. Next, the control system 106 may define the patient position correction data based on the at least one optical image 105 of the patient 600 and the at least one image analysis model 1118. For example, the control system 106 may determine multiple head landmarks of the patient 600 based on the at least one optical image 105 of the patient 600 and the at least one image analysis model 1118. For example, at least one image analysis model 1118 (e.g., at least one ML-based model) may be used to detect multiple head landmarks from at least one optical image 105 of the patient 600. In other words, the at least one optical image 105 of the patient 600 may be used as input data for the at least one image analysis model 1118, and multiple head landmarks of the patient 600 may be obtained as output data of the at least one image analysis model 1118. The determined multiple head landmarks of the patient 600 may include, for example, one or more of the head landmarks 502, 504, 506, 508, 510, 512, 802 described above with reference to step 410 of FIG. 4 and / or with reference to step 810 of FIG. 8A. Alternatively or additionally, the determined multiple head landmarks may include, for example, one or more of the other head landmarks of the patient 600. The control system 106 may determine patient position correction data based on the determined multiple head landmarks of the patient 600.The patient position correction data may include an indication of one or more positional errors in the patient position and / or respective corrections for correcting the one or more positional errors in the patient position. The one or more positional errors in the patient position may include, but are not limited to, head wobble, head twist, and / or head rotation, as described later in this application. According to one embodiment, the control system 106, under the guidance of the patient 600 and / or an operator of the dental X-ray imaging unit 102, can use the determined patient position correction data to correct one or more positional errors in the patient position via one or more user interface devices, such as a display device and / or a loudspeaker device. The one or more user interface devices may include the user interface device 140a and / or one or more other user interface devices. Alternatively or additionally, the control system 106 can use the patient position correction data to control components of the dental X-ray imaging unit 102 to move in accordance with the patient position correction data to correct one or more positional errors in the patient position. Alternatively, at least one internal imaging device 104b may be used, for example, for motion correction.

[0089] Correction of head twist and / or head sway can be considered as correction of out-of-plane position error. Next, an example of generating patient position correction data for correcting (i.e., correcting) head twist will be described. Assuming that the Y-axis comes from the back of the patient's 600 nose, rotation around this Y-axis represents head twist. Head twist can be detected, for example, based on two head landmarks located at the same height on both sides of the patient's 600 face. For example, the corners of the eyes may be used as the two head landmarks to determine head twist. Alternatively, two other head landmarks, such as earlobes, may be used to determine the direction of twist. A line may be formed between the two head landmarks, and the angle between the formed line and a reference horizontal line indicates the amount and direction of head twist. The generated patient position correction data may include the formed line between the two head landmarks and the formed angle between the formed line and the reference horizontal line. Head twist can be corrected, for example, by using the generated patient position correction data under the guidance of the patient 600 and / or the operator of the dental X-ray imaging unit 102, as described above. The guidance may be, for example, but is not limited to, visual guidance. Head twist may be corrected, for example, after acquiring at least one optical image in step 210 described above and before using dental atlas data in step 230 described above. Next, an example of generating patient position correction data to correct head wobble will be described. Assuming that the X-axis passes through both ears of the patient 600, rotation around this X-axis represents head wobble. Head wobble can be detected, for example, based on two head landmarks of the patient 600, which may depend on the imaging mode. In CT imaging, the two head landmarks are, for example, the alar and the tragus. In panoramic imaging, the two head landmarks are, for example, the earlobe and the orbit (e.g., the infraorbital region). A line is formed between two head landmarks, and the angle between the line and a reference horizontal line indicates the amount and direction of head wobble. In CT imaging, the line is sometimes called Camper's line, for example.In panoramic imaging, the formed line may be referred to, for example, as the Frankfurt Horizon (FH-line). The generated patient position correction data may include a line formed between two head landmarks and the angle formed between the formed line and a reference horizontal line. Head wobble may be corrected, for example, by using the generated patient position correction data in guidance by the patient 600 and / or the operator of the dental X-ray imaging unit 102, as described above. The guidance may be, for example, but is not limited to, visual guidance. Alternatively or additionally, head wobble may be corrected by utilizing the generated patient position correction data to control the patient support 124, 126 to move upward (in the case of a downward wobble) or downward (in the case of an upward wobble) until the formed line between the two head landmarks is completely horizontal, i.e., parallel to the reference horizontal line. Head wobble may be corrected, for example, after acquiring at least one optical image in step 210 described above and after receiving a scan request in step 220 described above, but before using the dental atlas data in step 230 described above. The out-of-plane position error correction may be used when the dental atlas data 1116 determines one or more dental structures of the patient 600 located within the head of the patient 600, for example, the aligned dental atlas data of the patient 600 described above.

[0090] Correction for head rotation can be considered as correction for plane rotation. Next, an example of generating patient position correction data for correcting head rotation will be described. Correction for head rotation can be performed after defining the ROI position in step 230 described above. After defining the ROI position, the imaging plane is linear. However, the imaging plane may rotate relative to the dental X-ray imaging unit 102. It may be assumed that the anterior-posterior axis (PA axis) of the patient 600 should be aligned with the anterior-posterior axis (PA axis) of the dental X-ray imaging unit 102, which is the main axis of the upper shelf 110 of the gantry section 112. Misalignment between the PA axis of the patient 600 and the PA axis of the dental X-ray imaging unit 102 may occur when the patient 600 rotates their head horizontally to the left or right. Assuming there is a Z axis from the patient's 600's feet through the center of the patient's 600's head, rotation around this Z axis causes head rotation. Head rotation can be detected, for example, based on two head landmarks located at the same height on either side of the patient's 600's face. For example, head rotation can be determined using the tragus as the two head landmarks. A line can be formed between the two head landmarks to determine the patient's 600's LR axis (from the left tragus to the right tragus). After correcting for planar motion, the IS axis of the dental X-ray imaging unit 102 can be a good estimate of the patient's IS axis. The IS and PA axes of the dental X-ray imaging unit 102 may be known or predefined. Because the PA axis is orthogonal to the LR and IS axes, the PA axis of the patient 600 can be defined as the cross product of the LR and IS axes. The angle between the PA axis of the patient 600 and the PA axis of the dental X-ray imaging unit 102 indicates the amount and direction of head rotation. The generated patient position correction data includes the angle formed between the PA axis of the patient 600 and the PA axis of the dental X-ray imaging unit 102. For example, in the case of CT images, since the scan trajectory does not move along the PA axis but rather rotates around the ROI, head rotation can be corrected by controlling the starting rotation angle of the gantry section 112 to rotate an amount equal to the opposite direction of the angle formed between the PA axis of the patient 600 and the PA axis of the dental X-ray imaging unit 102 contained in the generated patient position correction data.In the case of panoramic imaging, head rotation can be corrected, for example, as described above, using the generated patient position correction data for guidance of the patient 600 and / or the operator of the dental X-ray imaging unit 102. Guidance can be, for example, but not limited to, visual guidance. Alternatively or additionally, in the case of panoramic imaging, head rotation can be corrected by controlling the rotation of the PA axis of the dental X-ray imaging unit 102 to align with the PA axis of the patient 600, e.g., by pivoting the upper shelf 110 according to the formed angle between the PA axis of the patient 600 and the PA axis of the dental X-ray imaging unit 102 included in the generated patient position correction data. If the pivot point of the upper shelf 110 is different from the center of rotation of the head, the pivoting can cause unwanted movements in the X-axis and / or Y-axis orientation relative to the head of the patient 600. These unwanted movements in the X-axis and Y-axis orientation can be corrected, for example, with movements in opposite directions that are equal in size to the X-axis and Y-axis orientations. Alternatively or additionally, for panoramic imaging, head rotation can be corrected by defining a patient-specific scan trajectory as described above, because the patient-specific scan trajectory inherently takes into account whether the patient's head is rotated. Alternatively or additionally, for panoramic imaging, head rotation can be corrected by minimizing rotational errors in the region of the defined ROI location. For example, the correction can be performed by manipulating (i.e., optimizing) the starting position of the scan trajectory and / or the starting rotation angle of the gantry section 112.

[0091] FIG. 11 schematically illustrates an example of the control system 106 of the dental x-ray imaging system 100. The control system 106 may include a processor unit 1102, a data transfer unit 1104, a user interface unit 1106, and a memory unit 1108. The processor unit 1102 is configured to execute instructions and process data initiated by a user and / or a computer program (software). The processor unit 1102 may include at least one processor. The memory unit 1108 is configured to store and maintain data. The data may be instructions, computer programs, and any data files. The memory unit 1108 may include at least one memory. The memory unit 1108 may further include at least a data transfer application 1110 that controls the data transfer unit 1104, a user interface application 1112 that controls the UI unit 1106, and a computer program (code) 1114 that controls the operation of the control system 106. The memory unit 1108 and computer programs 1114, together with the processor unit 1102, can cause the control system 106 to perform at least one or more of the method steps and / or operations of the control system 106, as described above.

[0092] The data transfer unit 1104 may be configured to send control commands to other units, such as the dental X-ray imaging unit 1102. Additionally, the data transfer unit 1104 may receive data from other units, such as the dental X-ray imaging unit 102, the at least one optical imaging device 104a, 104b, the user interface unit 140b, a database, and / or other external units.

[0093] The user interface (UI) unit 1106 may be configured to input control commands, receive information and / or instructions, and display information. The UI unit 1106 may include at least a display, a screen, a touchscreen, at least one function key, a keyboard, a wired or wireless remote control, or other user input and / or output device.

[0094] The computer program 1114 may be a computer program product contained on a tangible, non-volatile (non-transitory) computer readable medium having computer program code 1114 embodied therein for use by a computer, i.e., the control system 106 .

[0095] FIG. 12 schematically illustrates an example of a method for detecting patient readiness. This method can be performed by the dental X-ray system 100 described above. Foreign objects in the head and neck region of the patient 600 can cause artifacts in the X-ray image. Typically, the foreign object is the patient's 600's accessories, such as eyeglasses, earrings, nose piercings, hair accessories, necklaces, and / or similar items. Alternatively or additionally, the foreign object may be improper protective equipment worn by the operator of the dental X-ray imaging unit 102. For example, a thyroid collar can corrupt a panoramic X-ray image. In step 1210, the control system 106 can acquire at least one optical image 105 of the patient 600. The at least one optical image 105 of the patient 600 can be acquired, for example, using at least one optical imaging device 104a, 104b of the dental X-ray system 102, such as at least one external imaging device 104a and / or at least one internal imaging device 104b, similar to step 210 described above. In step 1220, the control system 106 may detect one or more foreign objects based on the acquired at least one optical image 105 of the patient 600 and the at least one image analysis model 1118. In other words, the control system 106 may detect one or more foreign objects from the at least one optical image 105 of the patient 600 using the at least one image analysis model 1118, e.g., at least one AI-based model. The detected one or more foreign objects may be further classified using the at least one image analysis model 1118. In step 1230, in response to the detection of the one or more foreign objects in step 1220, the control system 106 may provide guidance to the patient 600 and / or an operator of the dental X-ray imaging unit 102 via one or more user interface devices, e.g., a display device and / or a public address system, to instruct them to remove the detected one or more foreign objects. The one or more user interface devices may include the user interface device 140a and / or one or more other user interface devices.

[0096] FIG. 13 schematically illustrates one embodiment of a method for detecting device readiness. This method can be performed by the dental X-ray system 100 described above. Different device accessories can be used in dental X-ray imaging by the dental X-ray imaging unit 102. The required device accessories may vary depending on the imaging mode. In step 1310, the control system 106 may acquire at least one optical image of the dental X-ray imaging unit 102. The at least one optical image of the dental X-ray imaging unit 102 may be captured, for example, by at least one internal imager 104b of the dental X-ray imaging unit 102, similar to step 610 described above. In step 1320, the control system 106 may receive a scan request similar to that described with reference to step 220 above, except that the scan request may further include device accessory data indicating required device accessories. In step 1330, the control system 106 can detect one or more device accessories based on the acquired at least one optical image 105 of the patient 600 and the at least one image analysis model 118. In other words, the control system 106 may use at least one image analysis model 1118, e.g., at least one AI-based model, to detect one or more device accessories from the at least one optical image 105 of the patient 600. The detected one or more device accessories may be further classified using the at least one image analysis model 1118 to identify the detected one or more device accessories, i.e., whether the detected one or more device accessories belong to required device accessories indicated in the scan request, or whether the detected one or more device accessories belong to incorrect device accessories that are not indicated as required device accessories in the scan request. In step 1230, in response to identifying one or more improper device accessories, the control system 106 may instruct the operator of the dental x-ray imaging unit 102 via one or more user interface devices, e.g., a display device and / or a speaker device, to remove or replace the one or more improper device accessories.The one or more user interface devices may include user interface device 140a and / or one or more other user interface devices.

[0097] At least some of the aspects of the present invention described above may reduce imaging times, at least partially eliminate the need for scout images in CT imaging, reduce patient radiation exposure, improve patient positioning, and / or minimize the need for additional imaging.

[0098] The specific examples provided in the above description should not be construed as limiting the applicability and / or interpretation of the appended claims. The list or collection of examples provided in the above description is not exhaustive unless expressly stated otherwise.

Claims

1. A dental x-ray imaging system (100) for taking dental x-ray images of a patient (600), comprising: a dental x-ray imaging unit (102); an X-ray source unit (114) that emits X-rays; an X-ray imaging detector unit (116) that receives the X-rays from the radiation source unit (114); a gantry section (112) including the radiation source section (114) and the imaging detector section (116); a dental x-ray imaging unit (102) comprising: a control system (106); acquiring at least one optical image (105) of the patient (600); receiving a scan request including region of interest (ROI) data; defining an ROI location based on the ROI data, the at least one optical image (105), dental atlas data (1116), and at least one image analysis model (1118) formed based on previously collected reference image data; a control system (106) configured to: A dental x-ray imaging system (100) comprising:

2. the at least one optical image (105) of the patient (600) includes at least one optical image in which the dentition of the patient (600) is at least partially visible; The control system (106) determining a plurality of head landmarks (502, 504, 506, 508, 510, 512) of the patient (600) based on the at least one optical image (105) of the patient (600) and the at least one image analysis model (1118); selecting, based on the dental atlas data (1116), a plurality of atlas landmarks corresponding to the plurality of cranial landmarks (502, 504, 506, 508, 510, 512) of the patient (600); Registering the plurality of atlas landmarks and the plurality of head landmarks (502, 504, 506, 508, 510, 512) of the patient (600) to determine aligned dental atlas data for the patient (600).

2. The dental x-ray imaging system (100) of claim 1, configured to:

3. 3. The dental X-ray imaging system of claim 2, wherein the control system is configured to define the ROI position based on the ROI data and the determined, registered dental atlas data of the patient.

4. The dental X-ray imaging system (100) of any one of claims 1 to 3, characterized in that the control system (106) is further configured to determine exposure parameters for scanning the patient (600) based on imaging mode data further included in the scan request, the at least one optical image (105) of the patient (600), and the at least one image analysis model (1118).

5. The control system (106) determining a plurality of head landmarks (502, 504, 506, 508, 510, 512, 802) of the patient (600) based on the at least one optical image (105) of the patient (600) and the at least one image analysis model (1118); determining head size data of the patient (600) based on the plurality of head landmarks (502, 504, 506, 508, 510, 512, 802) of the patient (600); The head size data is used to determine the exposure parameters.

5. The dental X-ray imaging system according to claim 4, wherein the dental X-ray imaging system is configured as follows:

6. The control system (106) further comprises: determining classification data for the patient (600) based on the at least one optical image (105) of the patient (600) and the at least one image analysis model (1118); Using the classification data to determine the exposure parameters 6. The dental X-ray imaging system according to claim 5, wherein the dental X-ray imaging system is configured as follows:

7. The control system (106) further comprises: determining at least one head landmark (502, 504, 506, 508, 510, 512, 802) of the patient (600) based on the at least one optical image (105) of the patient (600) and the at least one image analysis model (1118); determining height data of the patient (600) based on the at least one cranial landmark (502, 504, 506, 508, 510, 512, 802) of the patient (600); Using the determined height data, adjust the height of components of the dental x-ray imaging unit (102).

7. A dental X-ray imaging system (100) according to claim 1, characterized in that it is configured as follows:

8. The control system (106) further comprises: determining a plurality of body landmarks (1002) of the patient (600) based on the at least one optical image (105) of the patient (600) and the at least one image analysis model (1118); determining width data for the patient based on the plurality of body landmarks of the patient; Using the determined width data to mitigate the risk of collision between the patient and the gantry portion of the dental x-ray imaging unit.

8. A dental X-ray imaging system (100) according to any one of claims 1 to 7, characterized in that it is configured as follows:

9. 9. The dental X-ray imaging system (100) according to any one of claims 1 to 8, characterized in that it comprises at least one optical imaging device (104a, 104b) configured to capture the at least one optical image (105) of the patient (600).

10. 10. The dental x-ray imaging system (100) of claim 1, wherein the ROI data includes a representation of at least one of a single tooth, a range of teeth, a dental arch, both dental arches, a temporomandibular joint (TMJ), an entire dentition, and the TMJ.

11. The dental X-ray imaging system (100) of any one of claims 1 to 10, characterized in that the control system (100) is further configured to generate patient position correction data for positioning the patient based on the at least one optical image (105) of the patient (600) and the at least one image analysis model (1118).

12. A dental imaging method performed by an X-ray dental imaging system (100) according to any one of claims 1 to 11, comprising: acquiring (210) at least one optical image (105) of the patient (600); Receiving a scan request including region of interest (ROI) data (220); defining (230) an ROI location based on the ROI data, the at least one optical image (105), dental atlas data (1116), and at least one image analysis model (1118) formed based on previously collected reference image data; A method comprising:

13. A computer program (1114) comprising instructions that, when executed by a computer, cause the computer to carry out the method of claim 12.

14. 13. A tangible, non-volatile computer readable medium containing instructions that, when executed by a computer, cause the computer to perform the method of claim 12.

15. 1. A method for determining registered dental atlas data for a patient (600), comprising: acquiring (210) at least one optical image (105) of the patient (600), in which the dentition of the patient (600) is at least partially visible; determining (410) a plurality of head landmarks (502, 504, 506, 508, 510, 512) of the patient (600) based on the at least one optical image (105) of the patient (600) and at least one image analysis model (1118) formed based on previously collected reference image data; selecting (420) a plurality of atlas landmarks corresponding to the plurality of cranial landmarks (502, 504, 506, 508, 510, 512) of the patient (600) based on dental atlas data (1116); registering (430) the plurality of atlas landmarks and the plurality of head landmarks (502, 504, 506, 508, 510, 512) of the patient (600) to determine the aligned dental atlas data of the patient (600); A method comprising:

16. A computer program (1114) comprising instructions that, when executed by a computer, cause the computer to carry out the method of claim 15.

17. 16. A tangible, non-volatile computer readable medium containing instructions that, when executed by a computer, cause the computer to perform the method of claim 15.

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