X-ray imaging system and oral panoramic image reconstruction method thereof

Abstract

The present application discloses an X-ray imaging system and a method for reconstructing a panoramic oral image thereof, and relates to the field of radiological diagnosis technology. The method comprises: obtaining a dental arch curve of a user; obtaining a plurality of sampling points based on the dental arch curve; controlling the rotation of the horizontal boom, the position of the X-ray source and the X-ray sensor based on the plurality of sampling points, and obtaining a perspective view corresponding to each sampling point one by one; and obtaining a panoramic oral image based on the plurality of perspective views. The exposure assembly in the present application only needs to perform simple rotational motion or linear motion, and does not need to perform complex curvilinear motion. Compared with complex curvilinear motion, rotational motion and linear motion are easy to control precisely. That is, the present application can obtain a perspective view with higher precision, and thus obtain a panoramic oral image with higher precision.

Description

Technical Field

[0001] The present application relates to the technical field of radiological diagnosis, and in particular to an X-ray imaging system and an oral panoramic image reconstruction method thereof. Background Art

[0002] In order to obtain a panoramic view of the user's oral cavity, the prior art generally uses an X-ray imaging system to obtain perspective views of each point on the user's dental arch curve, and then superimposes the perspective views to obtain a panoramic view of the oral cavity. It should be clear that the existing X-ray imaging system includes an X-ray source and an X-ray sensor, and the distance between the X-ray source and the X-ray sensor is constant (that is, it cannot be adjusted). When in use, the X-ray imaging system not only needs to control the rotation of the X-ray source and the X-ray sensor through the rotating axis, but also needs to control the rotating axis to perform complex curved motion (see the specific implementation method for specific reasons). For example, the patent document with application number CN202010686999.5 and name of a multi-mode oral CBCT device discloses a similar X-ray imaging system.

[0003] It should be clear that if the motion trajectory of the rotating shaft, the X-ray source and the X-ray sensor (hereinafter referred to as the exposure assembly) is a curve, it is difficult to accurately control the motion trajectory of the exposure assembly. If it is difficult to accurately control the motion trajectory of the exposure assembly, it is difficult to obtain a high-precision perspective view, that is, it is difficult to obtain a high-precision oral panoramic view. Summary of the invention

[0004] The purpose of the present application is to provide an X-ray imaging system and an oral panoramic image reconstruction method thereof, so as to solve the technical problem that it is difficult to accurately control the motion trajectory of the exposure component.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] In a first aspect, the present application proposes a technical solution for a method for reconstructing an oral panoramic image, which is applied to an X-ray imaging system, wherein the X-ray imaging system comprises a horizontal suspension arm, an X-ray source disposed at a first end of the horizontal suspension arm, and an X-ray sensor disposed at a second end of the horizontal suspension arm; both the X-ray source and the X-ray sensor are capable of moving along the length direction of the horizontal suspension arm; the horizontal suspension arm is capable of central rotation around a first axis, and the first axis is parallel to the vertical direction; the method for reconstructing an oral panoramic image comprises:

[0007] Get the user's dental arch curve;

[0008] Based on the dental arch curve, obtaining multiple sampling points;

[0009] Based on the multiple sampling points, control the rotation of the horizontal boom, the positions of the X-ray source and the X-ray sensor, and obtain perspective views corresponding to each sampling point one by one;

[0010] Get a panoramic view of the oral cavity based on multiple perspective views.

[0011] As a specific solution in the technical solution of the present application, the acquisition of multiple sampling points based on the dental arch curve includes:

[0012] Acquiring a scanning step angle; wherein the scanning step angle is preset;

[0013] Based on the dental arch curve and the target point, a total scanning angle is acquired; the target point is an intersection point formed by the first axis and the plane where the dental arch curve is located;

[0014] A plurality of sampling points are acquired based on the scanning step angle and the total scanning angle.

[0015] As a specific solution in the technical solution of the present application, the controlling the rotation of the horizontal boom, the positions of the X-ray source and the X-ray sensor based on the multiple sampling points includes:

[0016] Based on the multiple sampling points, a current sampling point and a historical sampling point are acquired; the current sampling point and the historical sampling point are adjacent sampling points;

[0017] Based on the current sampling point and the target point, acquiring a first distance;

[0018] Based on the historical sampling points and the target point, acquiring a second distance;

[0019] Based on the first distance and the second distance, acquiring an adjusted distance;

[0020] During a time period when the horizontal boom rotates from the historical sampling point to the current sampling point, the positions of the X-ray source and the X-ray sensor are adjusted based on the adjustment distance.

[0021] As a specific solution in the technical solution of the present application, after obtaining the dental arch curve of the user, the method further includes:

[0022] Based on the dental arch curve, a target point is obtained; the target point includes a point in the plane where the dental arch curve is located, which has the smallest distance change from each point on the dental arch curve;

[0023] The position of the first axis is adjusted so that the first axis passes through the target point.

[0024] As a specific solution in the technical solution of the present application, the step of obtaining the target point based on the dental arch curve includes:

[0025] Based on the dental arch curve, a plurality of curve points are obtained; the curve points are any points in the dental arch curve;

[0026] Based on the dental arch curve, a plurality of prediction points are obtained; the prediction points are any points in the plane where the dental arch curve is located;

[0027] Obtaining the third distance between each predicted point and the plurality of curve points;

[0028] Based on the plurality of third distances, obtaining a variance corresponding to each prediction point one by one;

[0029] Based on the variance, the target point is obtained from the multiple predicted points.

[0030] As a specific solution in the technical solution of the present application, the step of obtaining the target point from the multiple predicted points based on the variance includes:

[0031] Based on the multiple prediction points, a first prediction point, a second prediction point, and a third prediction point that are not collinear are obtained; the first prediction point, the second prediction point, and the third prediction point are three prediction points with the smallest variance among the multiple prediction points; and the first variance, the second variance, and the third variance corresponding to the first prediction point, the second prediction point, and the third prediction point are increased in size;

[0032] Acquire a center point based on the first prediction point, the second prediction point, and the third prediction point;

[0033] Based on the center point and the third predicted point, a reference point is obtained; the reference point is any point away from the center point along a first direction; the first direction is from the third predicted point to the center point;

[0034] Based on the reference point, obtaining a fourth variance;

[0035] If the fourth variance satisfies the first preset condition, the target point is acquired based on the first variance and the fourth variance; otherwise, the third prediction point is updated.

[0036] As a specific solution in the technical solution of the present application, the updating of the third prediction point includes:

[0037] If the fourth variance is smaller than the first variance, the third prediction point is updated to an arbitrary point away from the center point along the first direction;

[0038] If the fourth variance is greater than the first variance and less than the third variance, the third prediction point is updated as the reference point;

[0039] If the fourth variance is greater than the third variance, the third prediction point is updated to be any point on the line between the center point and the third prediction point.

[0040] As a specific scheme in the technical scheme of the present application, the first preset condition includes: the number of updates of the third prediction point is greater than the first preset value; or the absolute value of the difference between the fourth variance and the target variance is less than the second preset value; the target variance includes the first variance or the average value of the first variance, the second variance and the third variance.

[0041] As a specific solution in the technical solution of the present application, the obtaining of multiple curve points based on the dental arch curve includes:

[0042] Obtaining the number of selected curve points; the number of selected points is preset;

[0043] Based on the dental arch curve, randomly obtaining a plurality of curve points of the same number as the selected number;

[0044] Alternatively, the multiple curve points include two end points of the dental arch curve; and the acquiring multiple curve points based on the dental arch curve includes:

[0045] Obtaining the number of selected curve points; the number of selected points is preset;

[0046] Based on the dental arch curve and the selected number, a plurality of curve points are obtained; and the intervals between adjacent curve points are equal.

[0047] In a second aspect, the present application proposes a technical solution of an X-ray imaging system, the X-ray imaging system comprising:

[0048] A horizontal boom, the horizontal boom being capable of central rotation about a first axis, the first axis being parallel to a vertical direction;

[0049] An X-ray source and an X-ray sensor; the X-ray source is disposed at a first end of the horizontal suspension arm, and the X-ray sensor is disposed at a second end of the horizontal suspension arm; both the X-ray source and the X-ray sensor are movable along the length direction of the horizontal suspension arm;

[0050] A reader for obtaining a user's dental arch curve;

[0051] A processor, configured to obtain a plurality of sampling points based on the dental arch curve;

[0052] A controller, configured to control the rotation of the horizontal boom, the positions of the X-ray source and the X-ray sensor based on the plurality of sampling points, and to obtain a perspective view corresponding to each sampling point one by one;

[0053] The processor is also used to obtain a panoramic image of the oral cavity based on multiple perspective images.

[0054] As a specific solution in the technical solution of the present application, the reader is also used to obtain a scanning step angle; the scanning step angle is preset;

[0055] The processor is further configured to obtain a total scanning angle based on the dental arch curve and a target point; the target point is an intersection point formed by the first axis and a plane where the dental arch curve is located;

[0056] And, based on the scanning step angle and the total scanning angle, a plurality of sampling points are acquired.

[0057] As a specific solution in the technical solution of the present application, the reader is also used to obtain a current sampling point and a historical sampling point based on the multiple sampling points; the current sampling point and the historical sampling point are adjacent sampling points;

[0058] The processor is further configured to obtain a first distance based on the current sampling point and the target point;

[0059] and, based on the historical sampling point and the target point, acquiring a second distance;

[0060] and, based on the first distance and the second distance, obtaining an adjusted distance;

[0061] The controller is further configured to adjust the positions of the X-ray source and the X-ray sensor based on the adjustment distance within a time period when the horizontal boom rotates from the historical sampling point to the current sampling point.

[0062] As a specific solution in the technical solution of the present application, the processor is further used to obtain a target point based on the dental arch curve; the target point includes a point in the plane where the dental arch curve is located with the smallest distance change from each point on the dental arch curve;

[0063] The controller is further configured to adjust a position of the first axis so that the first axis passes through the target point.

[0064] As a specific solution in the technical solution of the present application, the processor is further used to obtain a plurality of curve points based on the dental arch curve; the curve point is any point in the dental arch curve;

[0065] And, based on the dental arch curve, a plurality of prediction points are obtained; the prediction points are any points in the plane where the dental arch curve is located;

[0066] and, obtaining a third distance between each predicted point and the plurality of curve points;

[0067] And, based on the plurality of third distances, obtaining a variance corresponding to each prediction point one by one;

[0068] And, based on the variance, the target point is obtained from the multiple prediction points.

[0069] As a specific solution in the technical solution of the present application, the processor is further used to obtain, based on the multiple prediction points, a first prediction point, a second prediction point, and a third prediction point that are not collinear; the first prediction point, the second prediction point, and the third prediction point are three prediction points with the smallest variance among the multiple prediction points; and the first variance, the second variance, and the third variance corresponding to the first prediction point, the second prediction point, and the third prediction point are increased in size;

[0070] And, based on the first prediction point, the second prediction point and the third prediction point, obtaining a center point;

[0071] And, based on the center point and the third predicted point, a reference point is obtained; the reference point is any point away from the center point along a first direction; the first direction is from the third predicted point to the center point;

[0072] and, based on the reference point, obtaining a fourth variance;

[0073] And, if the fourth variance satisfies a first preset condition, the target point is obtained based on the first variance and the fourth variance; otherwise, the third prediction point is updated.

[0074] As a specific solution in the technical solution of the present application, the processor is further configured to, if the fourth variance is smaller than the first variance, update the third prediction point to any point away from the center point along the first direction;

[0075] And, if the fourth variance is greater than the first variance and less than the third variance, the third prediction point is updated as the reference point;

[0076] And, if the fourth variance is greater than the third variance, the third prediction point is updated to be any point on the line between the center point and the third prediction point.

[0077] As a specific scheme in the technical scheme of the present application, the first preset condition includes: the number of updates of the third prediction point is greater than the first preset value; or the absolute value of the difference between the fourth variance and the target variance is less than the second preset value; the target variance includes the first variance or the average value of the first variance, the second variance and the third variance.

[0078] As a specific solution in the technical solution of the present application, the reader is further used to obtain the selected number of the curve points; the selected number is preset;

[0079] The processor is further configured to randomly obtain a plurality of curve points having the same number as the selected number based on the dental arch curve;

[0080] Alternatively, the plurality of curve points include two end points of the dental arch curve; the reader is further used to obtain a selected number of the curve points; the selected number is preset;

[0081] The processor is also used to obtain a plurality of curve points based on the dental arch curve and the selected number; the spacing between adjacent curve points is equal.

[0082] Compared with the prior art, the beneficial effects of this application are:

[0083] The exposure assembly in the embodiment of the present application only needs to perform simple rotational motion or linear motion, and does not need to perform complex curvilinear motion. Compared with complex curvilinear motion, rotational motion and linear motion are easy to control accurately. That is, the present application can obtain a high-precision perspective view, and then obtain a high-precision oral panoramic view. BRIEF DESCRIPTION OF THE DRAWINGS

[0084] Figure 1 A schematic diagram of the structure of an X-ray imaging system proposed in an embodiment of the present application;

[0085] Figure 2 It is a schematic diagram of the movement of the exposure component in the prior art;

[0086] Figure 3 A schematic diagram of a flow chart of a method for reconstructing an oral panoramic image proposed in an embodiment of the present application;

[0087] Figure 4 A schematic diagram of the movement of an X-ray source and an X-ray sensor proposed in an embodiment of the present application;

[0088] Figure 5 A schematic diagram of the total scanning angle proposed in the embodiment of the present application;

[0089] Figure 6 A schematic diagram of obtaining various sampling points proposed in an embodiment of the present application;

[0090] Figure 7 A schematic diagram of another X-ray source and X-ray sensor motion proposed in an embodiment of the present application;

[0091] Figure 8 A schematic diagram of manually acquiring a target point according to an embodiment of the present application;

[0092] Fig. 9 A schematic diagram of the prediction points and curve points proposed in the embodiment of the present application;

[0093] Fig.10 A schematic diagram of acquiring a target point based on a dot matrix proposed in an embodiment of the present application;

[0094] Fig.11 A schematic diagram of another method of acquiring a target point based on a dot matrix proposed in an embodiment of the present application;

[0095] Fig.12 A schematic diagram of obtaining a center and a reference point based on a first prediction point, a second prediction point and a third prediction point proposed in an embodiment of the present application;

[0096] Fig.13 A schematic diagram of a moving path of an X-ray source proposed in an embodiment of the present application.

[0097] In the figure: 1. horizontal boom; 2. X-ray source; 3. X-ray sensor; 4. reader; 5. processor; 6. controller; 7. user; 8. dental arch curve; 9. movement trajectory; 10. central area. DETAILED DESCRIPTION

[0098] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0099] The technical solutions in the embodiments of the present application will be described clearly and completely below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0100] The terms "first", "second", etc. in the specification and claims of the embodiments of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence, such as the first prediction point and the second prediction point proposed below, which belong to different points. It should be understood that the points used in this way can be interchanged where appropriate, so that the embodiments described here can be implemented in an order other than the content illustrated or described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or modules is not necessarily limited to those steps or modules clearly listed, but may include other steps or modules that are not clearly listed or inherent to these processes, methods, products or devices. The division of modules that appear in the embodiments of the present application is only a logical division. There may be other division methods when implemented in actual applications, such as multiple modules can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the coupling or direct coupling or communication connection between each other shown or discussed can be through some interfaces, and the indirect coupling or communication connection between modules can be electrical or other similar forms, which are not limited in the embodiments of the present application. Furthermore, the modules or sub-modules described as separate components may or may not be physically separated, may or may not be physical modules, or may be distributed in multiple circuit modules, and some or all of the modules may be selected according to actual needs to achieve the purpose of the embodiment of the present application.

[0101] Before understanding the embodiments of the present application, it should be understood that the prior art uses an X-ray imaging system to obtain perspective images of various points on a dental arch curve based on a dental arch curve. Figure 2 As shown in Figure 2. The motion trajectory of the rotating axis is shown in Figure 2. Figure 2 As shown in the moving track 9 in FIG. 1 , the dental arch curve of user 7 is as follows: Figure 2 As shown in the dental arch curve 8 in the figure, the moving trajectory 9 is similar to the dental arch curve 8. Assume that points D2 and D4 on the dental arch curve 8 are two adjacent exposure points (in the actual process, there are many exposure points between points D2 and D4. For the convenience of observation and understanding, they are shown in the figure below). Figure 2 In other words, if the perspective view of point D2 on the dental arch curve 8 after exposure is obtained, the next step is to obtain the perspective view of point D4 on the dental arch curve 8. Figure 2As shown, in order to obtain a clear exposure image each time, during each exposure, not only the distance S between the X-ray source 2 and the X-ray sensor 3 needs to be constant, but also the distance between the X-ray source 2 and the exposure point on the dental arch curve 8 needs to be equal at each exposure position (it cannot be completely equal, but can only be approximately equal). In other words, Figure 2 As shown, the distance L1 and the distance L2 need to be as equal as possible. In other words, after obtaining the perspective view of the point D2 on the dental arch curve 8 in the prior art, if it is necessary to obtain the perspective view of the point D4 on the dental arch curve 8, it is necessary to move the rotation axis from the point D1 on the moving trajectory 9 to the point D3 along the moving trajectory 9 so that the distance L1 and the distance L2 are equal. During this period, the X-ray source 2 and the X-ray sensor 3 need to be rotated so that the line between the X-ray source 2 and the X-ray sensor 3 passes through the point D4 (i.e., the exposure point).

[0102] In summary, the prior art not only needs to control the rotation axis, X-ray source 2 and X-ray sensor 3 (i.e., exposure assembly) in the X-ray imaging system to perform complex curved motion, but also needs to control the X-ray source 2 and X-ray sensor 3 to perform rotational motion based on the rotation axis. It is easy to understand that the precise control of the exposure assembly to perform curved motion requires high technical requirements and is difficult to achieve.

[0103] In order to solve the above technical problems and improve the control accuracy of the motion trajectory of the exposure component, the present application proposes an embodiment of a method for reconstructing an oral panoramic image. Specifically, the oral panoramic image reconstruction method is applied to an X-ray imaging system. Figure 1 As shown, the X-ray imaging system includes a horizontal arm 1, an X-ray source 2 disposed at a first end of the horizontal arm 1, and an X-ray sensor 3 disposed at a second end of the horizontal arm. The X-ray source 2 and the X-ray sensor 3 can both be arranged along the length direction of the horizontal arm 1 (i.e. Figure 1 The horizontal boom 1 can rotate around a first axis, which is parallel to the vertical direction.

[0104] It should be clear that controlling the horizontal boom 1 to rotate is a mature technology and will not be described in detail here. A linear motion structure (for example, a linear guide or a lead screw transmission structure, etc.) can be set between the X-ray source 2 and the horizontal boom 1 to enable the X-ray source 2 to move along the length direction of the horizontal boom 1. Of course, a linear motion structure can also be set between the X-ray sensor 3 and the horizontal boom 1, which will not be described in detail here. Since the linear motion structure that can make two parts (that is, the horizontal boom 1 and the X-ray source 2, or the horizontal boom 1 and the X-ray sensor 3) produce linear relative motion is also a mature technology, it will not be described in detail here.

[0105] Specifically, Figure 3As shown, the oral panoramic image reconstruction method proposed in the embodiment of the present application includes steps S100 to S400.

[0106] Step S100: Obtain the dental arch curve of the user.

[0107] In an embodiment of the present application, the dental arch curve of the user can be obtained in any manner. For example, the dental arch curve of the user can be obtained based on the CBCT image, such as the method proposed in the patent document with patent authorization number CN112102495B, entitled A method for generating dental arch surfaces based on CBCT images. Alternatively, the dental arch curve of the user can be obtained based on binocular vision, such as the method proposed in the patent application document with patent application number 202010655271.6, entitled A method for obtaining human dental arch curves based on binocular vision. That is to say, in an embodiment of the present application, the dental arch curve of the user can be obtained based on any method. Since there are many methods for obtaining the dental arch curve of the user in the prior art, they are not listed one by one here to avoid redundancy.

[0108] Step S200: Acquire multiple sampling points based on the dental arch curve.

[0109] It should be clear that in the embodiments of the present application, multiple sampling points can be obtained in any manner based on the dental arch curve. For example, in the embodiments of the present application, multiple sampling points can be obtained randomly on the dental arch curve, or multiple sampling points can be obtained on the dental arch curve, and the spacing between adjacent sampling points is equal.

[0110] It should be clear that Figure 4 This is a schematic diagram (top view) of the movement of an X-ray source 2 and an X-ray sensor 3 (i.e., an exposure assembly) proposed in an embodiment of the present application. The intersection of the first axis and the plane where the dental arch curve 8 is located is defined as the target point (i.e. Figure 4 D5 in the figure), such as Figure 4 As shown, the first axis is perpendicular to the paper surface. Assume that point D2 and point D4 on the dental arch curve 8 are two adjacent exposure points (i.e., the same Figure 2 In other words, if the perspective image of point D2 on the dental arch curve 8 is obtained after exposure, the next step is to obtain the perspective image of point D4 on the dental arch curve 8. As can be seen from the above, in the process of obtaining each perspective image, the distance S between the X-ray source 2 and the X-ray sensor 3 needs to be constant. In order to obtain a clear exposure image every time, it is necessary to ensure that at each exposure position, the distance between the X-ray source 2 and the exposure point on the dental arch curve 8 (that is, the sampling point below) should be as equal as possible. In other words, if Figure 4As shown, when exposing point D2, the distance L1 between the X-ray source 2 and point D2 and the distance L2 between the X-ray source 2 and point D4 should be as equal as possible when exposing point D4.

[0111] In the embodiment of the present application, after obtaining the perspective view of point D2, it is only necessary to rotate around the first axis (that is, the target point D5) (the rotation direction is as follows: Figure 4 The horizontal boom 1 is moved in the direction C) shown in the figure so that the line between the X-ray source 2 and the X-ray sensor 3 passes through the point D4. During this period, the X-ray source 2 and the X-ray sensor 3 need to be moved along the first direction (i.e., the length direction of the horizontal boom 1) so that the distance L1 and the distance L2 are equal.

[0112] It should be clear that if Figure 2 and Figure 4 As shown, compared with the prior art, the various components (e.g., horizontal boom, X-ray source, and X-ray sensor) in the embodiment of the present application only need to perform simple rotational motion or linear motion, and do not need to perform complex curvilinear motion. Compared with controlling the exposure assembly to perform precise curvilinear motion, it is relatively simple to control the exposure assembly to perform precise linear motion. In addition, in the embodiment of the present application, components such as the horizontal boom and the rotating shaft do not need to perform linear motion. Compared with the prior art in which the rotating shaft needs to perform linear motion together with the X-ray source and the X-ray sensor, the motion inertia of the embodiment of the present application when used is also relatively low.

[0113] It should be clear that in order to accurately obtain the perspective image after exposure at each sampling point, it is necessary to pass the line between the X-ray source 2 and the X-ray sensor 3 through the sampling point (for example, Figure 4 At the same time as D2 and D4 in the figure, the X-ray source 2 and the X-ray sensor 3 are adjusted to the preset position (that is, the distance between the X-ray source 2 and the X-ray sensor 3 needs to be kept at Figure 4 S in the figure, the distance between the X-ray source 2 and the sampling point is L1, Figure 4 In the example, L1=L2), and X-ray source 2 need to be exposed at the same time. That is, at each sampling point, the above three actions need to be performed synchronously.

[0114] If the sampling points are obtained in a random manner, it is difficult to achieve complete synchronization of the above three actions in the subsequent control process. In order to facilitate the subsequent control of the above three actions to be synchronized, in one embodiment of the present application, step S200, based on the dental arch curve, obtains multiple sampling points, including steps S210 to S230.

[0115] Step S210: Obtain the scanning step angle.

[0116] It should be clear that, in order to facilitate subsequent control, in the embodiment of the present application, the horizontal arm 1 can be controlled to rotate at a constant speed, and the above three actions can be controlled to achieve synchronization at the scanning step angle (that is, the rotation angle of the horizontal arm 1). In this embodiment, the scanning step angle can be preset according to demand, for example, the scanning step angle can be 0.10°, 0.15° or 0.20°, etc.

[0117] Step S220: Based on the dental arch curve and the target point, the total scanning angle is acquired.

[0118] Specifically, the target point is the intersection of the first axis and the plane where the dental arch curve 8 is located. In this embodiment, the total scanning angle is Figure 5 As shown in the angle B in FIG. 8 , the line between the target point and the first end point of the dental arch curve 8 is defined as the first line segment; the line between the target point and the second end point of the dental arch curve 8 is defined as the second line segment. Angle B is the angle formed by the first line segment and the second line segment and directed toward the dental arch curve 8.

[0119] Step S230: Acquire multiple sampling points based on the scanning step angle and the total scanning angle.

[0120] In a specific embodiment of the present application, if the angle B is 270° and the scanning step angle is 0.15°, the number of sampling points obtained is 1800. Specifically, the sampling points obtained are as follows: Figure 6 As shown, point D5 is the target point, and each hollow circle on the dental arch curve 8 represents each sampling point.

[0121] Step S300: Based on the multiple sampling points, the rotation of the horizontal boom 1, the positions of the X-ray source 2 and the X-ray sensor 3 are controlled to obtain perspective views corresponding to each sampling point.

[0122] It should be clear that in the embodiments of the present application, the rotation of the horizontal boom, the positions of the X-ray source and the X-ray sensor can be controlled in any manner based on the multiple sampling points, so as to obtain a perspective view corresponding to each sampling point one by one.

[0123] In a specific embodiment of the present application, step S300, based on the multiple sampling points, controls the rotation of the horizontal boom 1, the positions of the X-ray source 2 and the X-ray sensor 3, and obtains a perspective view corresponding to each sampling point one by one, including steps S310 to S350.

[0124] Step S310: Based on the multiple sampling points, obtain the current sampling point and the historical sampling points.

[0125] In an embodiment of the present application, the current sampling point and the historical sampling point are adjacent sampling points. Figure 4 As shown, assuming that point D2 and point D4 are adjacent sampling points, if the current sampling point is D4, point D2 is a historical sampling point.

[0126] Step S320: Acquire a first distance based on the current sampling point and the target point.

[0127] It should be clear that the first distance is the distance between the current sampling point and the target point. Obtaining the distance between two points is a mature technology and will not be described in detail here.

[0128] Step S330: Acquire a second distance based on the historical sampling points and the target point.

[0129] It should be clear that the second distance is the distance between the historical sampling point and the target point. Obtaining the distance between two points is a mature technology and will not be described in detail here.

[0130] Step S340: acquiring an adjusted distance based on the first distance and the second distance.

[0131] It should be noted that the adjustment distance is the difference between the first distance and the second distance. Figure 4 As shown, assuming that the distance between the target point D5 and the historical sampling point D2 is S1, and the distance between the target point D5 and the current sampling point is S2, the adjusted distance is S2-S1.

[0132] Step S350: During the time period when the horizontal boom 1 rotates from the historical sampling point to the current sampling point, the positions of the X-ray source and the X-ray sensor are adjusted based on the adjustment distance.

[0133] As can be seen from the foregoing, in this embodiment, the time for the horizontal boom 1 to rotate to each sampling point is the same. That is, in this embodiment, Figure 4 As shown, before the horizontal boom 1 rotates from point D2 to point S4, the X-ray source and the X-ray sensor can be adjusted to corresponding positions based on the adjustment distance.

[0134] It is easy to understand that if the adjustment distance is positive, it means that the position of the X-ray source and the X-ray sensor needs to be adjusted along the first direction (that is, the length direction of the horizontal boom 1) away from the target point D5; if the adjustment distance is negative, it means that the position of the X-ray source and the X-ray sensor needs to be adjusted in the opposite direction of the above direction.

[0135] Step S400: Acquire a panoramic image of the oral cavity based on multiple perspective images.

[0136] It should be clear that obtaining a panoramic view of the oral cavity based on multiple perspective views is a mature technology and will not be elaborated here.

[0137] The various components (e.g., horizontal boom, X-ray source, and X-ray sensor) in the embodiments of the present application only need to perform simple rotational motion or linear motion, and do not need to perform complex curvilinear motion. Compared with complex curvilinear motion, rotational motion and linear motion are easy to control accurately, and the motion inertia generated by linear motion is small.

[0138] It should be clear that the combination of the rotating shaft, X-ray source and X-ray sensor in the prior art is relatively heavy. Its acceleration and deceleration during the curved motion will generate a large motion inertia, causing the X-ray imaging system to vibrate. In the process of acquiring each perspective view, if the X-ray imaging system vibrates, at the very least, the acquired oral panoramic view will have a large error, and at the worst, the X-ray imaging system will be deformed and its service life will be reduced. In the embodiment of the present application, components such as the horizontal boom and the rotating shaft do not need to perform linear motion. Compared with the prior art in which the rotating shaft needs to perform linear motion together with the X-ray source and the X-ray sensor, the motion inertia of the embodiment of the present application is further reduced when used.

[0139] As can be seen from the foregoing, before the horizontal arm 1 rotates from point D2 to point S4, the X-ray source and the X-ray sensor need to move a distance of S2-S1 on the horizontal arm 1. It is easy to understand that if the value of S2-S1 is larger, the motion inertia formed during the movement of the X-ray source and the X-ray sensor will be larger; if the value of S2-S1 is smaller, the motion inertia formed during the movement of the X-ray source and the X-ray sensor will be smaller.

[0140] In order to further reduce the motion inertia generated during the movement of the X-ray source and the X-ray sensor, in one embodiment of the present application, after step S100, after acquiring the dental arch curve of the user, the method further includes steps S500 and S600.

[0141] It should be clear that, in the embodiment of the present application, step S100 to step S600 do not represent the order in which the steps are executed, but are only used to distinguish different steps.

[0142] Step S500: Acquire a target point based on the dental arch curve.

[0143] It should be clear that the target point can be the point in the plane where the dental arch curve is located with the smallest distance change from each point on the dental arch curve (hereinafter referred to as the optimal point). It is easy to understand that if the target point is the point in the plane where the dental arch curve is located with the smallest distance change from each point on the dental arch curve, then in the subsequent control process, the moving distance of the X-ray source and the X-ray sensor is also the smallest, that is, the motion inertia formed during the movement of the X-ray source and the X-ray sensor can be minimized.

[0144] Specifically, Figure 7 This is another motion diagram of an X-ray source 2 and an X-ray sensor 3 (i.e., an exposure assembly) proposed in an embodiment of the present application (top view), wherein point D5 is the optimal point. Figure 4 and Figure 7 It can be seen from the embodiment that from point D2 to point D4, Figure 4 The moving distance of the X-ray source 2 and the X-ray sensor 3 in the embodiment is obviously greater than Figure 7 The moving distance of the X-ray source 2 and the X-ray sensor 3 in the embodiment. That is, Figure 7 In the embodiment, the motion inertia formed by the X-ray source 2 and the X-ray sensor 3 must be smaller than Figure 4 The motion inertia formed by the X-ray source 2 and the X-ray sensor 3 in the embodiment.

[0145] It should be clear that in actual operation, it is difficult to obtain the optimal point on the plane where the dental arch curve is located. Therefore, in this embodiment, the target point can be any point close to the optimal point. That is to say, in this embodiment, the target point can be obtained in any way based on the dental arch curve. For example, the target point can be manually determined based on the naked eye. Figure 8 As shown, the distances from point D5 to various points on the dental arch curve 8 observed by naked eyes are basically the same, so point D5 can be directly used as the target point.

[0146] In order to improve the accuracy of the acquired target point, that is, to make the target point closer to the optimal point, in one embodiment of the present application, step S500, based on the dental arch curve, acquires the target point, including steps S510 to S550.

[0147] Step S510: Based on the dental arch curve, a plurality of curve points are obtained.

[0148] It should be clear that the curve point is any point in the dental arch curve. In this embodiment, multiple curve points can be obtained based on the dental arch curve using any method. For example, in one embodiment of the present application, step S510, based on the dental arch curve, obtains multiple curve points, including step S511 and step S512.

[0149] Step S511: Obtain the selected number of the curve points.

[0150] In the embodiment of the present application, the selected number is preset. That is, in the present embodiment, there is no restriction on the number of curve points, for example, the number of curve points can be 20, 100, 200, etc.

[0151] Step S512: Based on the dental arch curve, a plurality of curve points having the same number as the selected number are randomly obtained.

[0152] It should be clear that the random acquisition method can effectively avoid the acquired curve points being too concentrated, thereby affecting the accuracy of the target points acquired subsequently.

[0153] In another embodiment of the present application, the multiple curve points include two endpoints of the dental arch curve, and step S510, based on the dental arch curve, obtains multiple curve points, including step S513 and step S514.

[0154] Step S513: Obtain the selected number of the curve points.

[0155] In the embodiment of the present application, the selected number is preset. That is, in the present embodiment, there is no restriction on the number of curve points, for example, the number of curve points can be 10, 80, 1000, etc.

[0156] Step S514: Based on the dental arch curve and the selected number, a plurality of curve points are obtained, and the intervals between adjacent curve points are equal.

[0157] That is to say, in this embodiment, if the length of the dental arch curve is T and the number of selected curve points is Z, then on the dental arch curve, from any end point of the dental arch curve, a point is selected as a curve point every T / (Z-1). This method can select curve points in each part of the dental arch curve, and thus more accurate target points can be obtained in subsequent steps.

[0158] Step S520: Based on the dental arch curve, a plurality of prediction points are obtained.

[0159] It should be clear that in the embodiments of the present application, the predicted point refers to a point that may be a target point. In other words, the predicted point is any point in the plane where the dental arch curve is located. In other words, any point in the plane where the dental arch curve is located may be a target point.

[0160] Step S530: Obtain the third distance between each prediction point and the multiple curve points.

[0161] In the embodiment of the present application, if there are n curve points and m prediction points, the calculation formula for the third distance between the kth prediction point and the ith curve point is as follows:

[0162]

[0163] Among them, d ik is the third distance between the kth prediction point and the ith curve point; (x k ,y k ) is the coordinate of the kth prediction point; (x i ,y i ) are the coordinates of the i-th curve point.

[0164] It is easy to understand that, since there are n curve points, each prediction point can form n third distances with n curve points. Fig. 9 As shown, in a specific embodiment of the present application, if the prediction point has two (that is, Fig. 9 ), 5 curve points are selected on the dental arch curve, then the D6 point can form 5 third distances with the 5 curve points, and the D7 point can also form 5 third distances with the 5 curve points.

[0165] Step S540: Based on the plurality of third distances, obtain a variance corresponding to each prediction point.

[0166] It should be clear that the variance is a measurement parameter of the degree of discreteness between a set of data, that is, the variance is used to measure the degree of deviation between each data. That is to say, in this embodiment, the variance between the multiple third distances corresponding to each prediction point can be used to determine whether the distance change of the prediction point from each point on the dental arch curve is the smallest. Of course, in other embodiments of the present application, indicators such as standard deviation, range or coefficient of variation can also be used to determine whether the distance change of the prediction point from each point on the dental arch curve is the smallest.

[0167] In an embodiment of the present application, based on the plurality of third distances, a calculation formula for obtaining a variance corresponding to each prediction point is as follows:

[0168]

[0169] Among them, V k is the variance of each third distance corresponding to the kth prediction point; n is the number of third distances; d i is the i-th third distance corresponding to the k-th prediction point; is the average value of the third distances corresponding to the k-th prediction point.

[0170] Step S550: Based on the variance, the target point is obtained from the multiple predicted points.

[0171] It should be noted that in the embodiments of the present application, it is difficult to accurately find the point (i.e., the optimal point) with the smallest distance change from each point on the dental arch curve on the plane where the dental arch curve is located. In most cases, only a point close to the optimal point can be found as the target point.

[0172] In the embodiment of the present application, the target point can be obtained from multiple prediction points in any manner based on the variance of each prediction point. For example, the target point can be obtained by at least several methods described below.

[0173] In one embodiment of the present application, Fig. 9 As shown in FIG. 1 , we connect the two end points of the dental arch curve 8, and the area enclosed by the connecting line and the dental arch curve 8 is the central area 10, and the target point must be located in the central area 10. Therefore, it can be Fig.10 As shown, a dot matrix covering the central area 10 is set, and the variance of each point in the dot matrix is ​​calculated, and the point with the smallest variance is taken as the target point.

[0174] It is easy to understand that in the embodiment of the present application, the denser the points in the dot matrix, the closer the target point is to the optimal point. The denser the points in the dot matrix, the greater the amount of calculation. As can be seen from the foregoing, the target point must be located in the central area 10. In order to reduce the amount of calculation in this embodiment, it can be as follows Fig.11 As shown, only the variance of the points located in the central area 10 of the dot matrix is ​​calculated.

[0175] It should be clear that in order to ensure that the accuracy of the target point obtained is high enough (that is, close to or equal to the optimal point), the number of points in the dot matrix needs to be set to be large enough (for example, 1000 or 10000), that is, a large amount of calculation is required to obtain the target point by means of the dot matrix. In order to reduce the amount of calculation to obtain the target point, that is, to increase the speed of finding the target point, in one embodiment of the present application, step S550, based on the variance, obtains the target point from the multiple predicted points, including steps S551 to S555.

[0176] Step S551: based on the plurality of prediction points, obtaining a first prediction point, a second prediction point and a third prediction point that are not collinear.

[0177] In an embodiment of the present application, the first prediction point, the second prediction point and the third prediction point may be any three non-collinear points in the plane where the dental arch curve 8 is located. For example, the first prediction point, the second prediction point and the third prediction point may be three prediction points with the smallest variance among multiple prediction points in the dot matrix of the previous embodiment (the number of points in the dot matrix may be small, a few, a dozen or dozens). Alternatively, the first prediction point, the second prediction point and the third prediction point may be the two endpoints and the midpoint of the dental arch curve 8. In this embodiment, the first variance, the second variance and the third variance corresponding to the first prediction point, the second prediction point and the third prediction point in sequence increase in size. That is, among the first prediction point, the second prediction point and the third prediction point, the third prediction point is the point farthest from the optimal point, and the first prediction point is the point closest to the optimal point.

[0178] Step S552: acquiring a center point based on the first prediction point, the second prediction point and the third prediction point.

[0179] In an embodiment of the present application, the center point may be any point in the area enclosed by the lines connecting the first prediction point, the second prediction point, and the third prediction point. For example, in an embodiment of the present application, if the coordinates of the first prediction point are (x1, y1), the coordinates of the second prediction point are (x2, y2), and the coordinates of the third prediction point are (x3, y3), then the coordinates of the center point may be ((x1+x2+x3) / 3, (y1+y2+y3) / 3).

[0180] Step S553: ​​Acquire a reference point based on the center point and the third prediction point.

[0181] It should be clear that, among the first prediction point, the second prediction point and the third prediction point, the third prediction point is the point farthest from the optimal point. That is to say, the first prediction point and the second prediction point are closer to the optimal point than the third prediction point. In other words, the optimal point should be sought in the direction in which the third prediction point approaches the first prediction point and the second prediction point. Therefore, in an embodiment of the present application, the reference point may be any point away from the center point along the first direction. In this embodiment, the first direction may be a specific direction in the direction in which the third prediction point approaches the first prediction point and the second prediction point. For example, the first direction may be a direction from the third prediction point to the center point, or the first direction may be a direction from the third prediction point to the midpoint of the line connecting the first prediction point and the second prediction point.

[0182] In this embodiment, the purpose of obtaining the reference point is to find the optimal point. As can be seen from the foregoing, the reference point can be any point away from the center point along the first direction. Fig.12As shown, it is assumed that the first predicted point is point D8, the second predicted point is point D9, the third predicted point is point D10, the center point is point D11, and the reference point is point D12 (that is, any point away from the center point along the first direction).

[0183] In this embodiment, the reference point can be obtained by calculating using the following calculation formula. The formula is as follows:

[0184] D12=D11+α(D11-D10)

[0185] Among them, D12 is the coordinate of the reference point; D11 is the coordinate of the center point; D10 is the coordinate of the third prediction point; α is the first correction coefficient, which can be a fixed value (for example, 1 or 2) or a dynamically changing value (for example, 2 / the number of updates of the third prediction point, the number of updates of the third prediction point is shown below).

[0186] Step S554: Based on the reference point, obtain a fourth variance.

[0187] As can be seen from the previous text, based on the reference point and in combination with each curve point, the variance corresponding to the reference point (that is, the fourth variance) can also be obtained, which will not be elaborated here.

[0188] Step S555: if the fourth variance satisfies the first preset condition, acquiring the target point based on the first variance and the fourth variance; otherwise, updating the third prediction point.

[0189] It should be clear that after multiple iterations of step S552 and step S555, a target point close to the optimal point can be finally obtained. This embodiment obtains the target point by calculation, which has higher accuracy than the target point obtained by visual observation. In addition, the method for obtaining the target point proposed in this embodiment only needs to be iterated a dozen or dozens of times (that is, only the variance needs to be calculated a dozen or dozens of times). Compared with obtaining the target point by lattice calculation, the method of this embodiment can greatly reduce the amount of calculation when finding the target point, that is, improve the speed of finding the target point.

[0190] In an embodiment of the present application, the first preset condition may be any condition for stopping the iterative update. For example, the first preset condition may include that the number of updates for the third prediction point is greater than a first preset value, and the first preset value may be any positive integer greater than 1. Alternatively, the absolute value of the difference between the fourth variance and the target variance is less than a second preset value. In this embodiment, the target variance may be the first variance, or the target variance may be the average value of the first variance, the second variance, and the third variance. In this embodiment, the second preset value may be an empirical value obtained from multiple experiments.

[0191] In one embodiment of the present application, step S555, updating the third prediction point, includes steps S556 to S558.

[0192] Step S556: If the fourth variance is smaller than the first variance, the third prediction point is updated to an arbitrary point away from the center point along the first direction.

[0193] It should be clear that if the fourth variance is less than the first variance, it means that among the first prediction point, the second prediction point, the third prediction point and the reference point, the reference point is closest to the optimal point. In this embodiment, the reference point can be updated to the first prediction point of the next iteration, the first prediction point of the current iteration can be updated to the second prediction point of the next iteration, and the second prediction point of the current iteration can be updated to the third prediction point of the next iteration.

[0194] It should be clear that among the first prediction point, the second prediction point, the third prediction point and the reference point, the reference point is closest to the optimal point. That is, the distance between each point and the optimal point along the line between the center point and the reference point in the first direction decreases. That is to say, we name the point with the next unit length (which can be any length) along the first direction with the reference point as the center as the first point. Relative to the reference point, the first point is likely to be closer to the optimal point. In order to increase the speed of approaching the optimal point, in one embodiment of the present application, the first prediction point, the second prediction point and the third prediction point of the next round of iteration can be updated to the first prediction point, the second prediction point and the replacement point of this round. The coordinates of the replacement point can be D12+β (D12-D11), where D12 is the coordinate of the reference point; D11 is the coordinate of the center point; β is the second correction coefficient, which is similar to the first correction coefficient. It can be a fixed value (for example, 1 or 2) or a dynamically changing value, which will not be repeated here.

[0195] It should be clear that if the second correction coefficient is 2, the replacement point can be located outside the range formed by the first prediction point, the second prediction point and the third prediction point, that is, the target point obtained subsequently can be prevented from falling into the local optimum.

[0196] Step S557: If the fourth variance is greater than the first variance and less than the third variance, the third prediction point is updated as the reference point.

[0197] It should be clear that if the fourth variance is greater than the first variance but less than the third variance, it means that the optimal point is likely to be near the area formed by the first prediction point, the second prediction point and the reference point. That is, the third prediction point of the next iteration can be updated as the reference point.

[0198] Step S558: If the fourth variance is greater than the third variance, the third prediction point is updated to any point on the line between the midline point and the third prediction point.

[0199] It should be clear that if the fourth variance is greater than the third variance, it means that the third prediction point is closer to the optimal point relative to the reference point. In other words, the optimal point is likely to be near the line connecting the third prediction point and the center point. In this embodiment, the third prediction point can be replaced by the center point for the next round of iterative update. Alternatively, in another embodiment of the present application, the third prediction point can be updated to D11+θ(D10-D11), where D11 is the coordinate of the center point; D10 is the coordinate of the third prediction point; θ is the third correction coefficient, which is similar to the first correction coefficient and the second correction coefficient. It can be a fixed value (for example, 0.5) or a dynamically changing value, which will not be elaborated here.

[0200] Step S600: adjusting the position of the first axis so that the first axis passes through the target point.

[0201] It should be clear that adjusting the position of the first axis (ie adjusting the rotation center position of the horizontal boom 1) is a mature technology and will not be described in detail here.

[0202] In a specific embodiment of the present application, during the entire scanning exposure process, the curve of the X-ray source moving along the first direction on the horizontal boom 1 is as follows: Fig.12 As shown, the ordinate is the relative position of the X-ray source along the first direction and the horizontal boom 1, and the abscissa is time.

[0203] This embodiment can minimize the movement amplitude during the subsequent movement of the X-ray source and the X-ray sensor by finding a target point close to the optimal point, that is, it can minimize the movement inertia generated by the movement of the X-ray source and the X-ray sensor.

[0204] After introducing the embodiment of the oral panoramic image reconstruction method proposed in the present application, the following introduces an embodiment of an X-ray imaging system proposed in the present application. Figure 1 As shown, the X-ray imaging system comprises:

[0205] A horizontal boom 1, wherein the horizontal boom 1 is capable of central rotation around a first axis, wherein the first axis is parallel to the vertical direction;

[0206] An X-ray source 2 and an X-ray sensor 3; the X-ray source 2 is disposed at a first end of the horizontal boom 1, and the X-ray sensor 3 is disposed at a second end of the horizontal boom 1; both the X-ray source and the X-ray sensor are movable along the length direction of the horizontal boom;

[0207] Reader 4, used to obtain the dental arch curve of the user;

[0208] A processor 5, configured to obtain a plurality of sampling points based on the dental arch curve;

[0209] A controller 6, configured to control the rotation of the horizontal boom, the positions of the X-ray source and the X-ray sensor based on the plurality of sampling points, and to obtain a perspective view corresponding to each sampling point one by one;

[0210] The processor 5 is further configured to obtain a panoramic view of the oral cavity based on multiple perspective views.

[0211] As a specific embodiment of the present application, the reader 4 is further used to obtain a scanning step angle; the scanning step angle is preset;

[0212] The processor 5 is further configured to obtain a total scanning angle based on the dental arch curve and a target point; the target point is an intersection point formed by the first axis and the plane where the dental arch curve is located;

[0213] And, based on the scanning step angle and the total scanning angle, a plurality of sampling points are acquired.

[0214] As a specific embodiment of the present application, the reader 4 is further used to obtain a current sampling point and a historical sampling point based on the multiple sampling points; the current sampling point and the historical sampling point are adjacent sampling points;

[0215] The processor 5 is further configured to obtain a first distance based on the current sampling point and the target point;

[0216] and, based on the historical sampling point and the target point, acquiring a second distance;

[0217] and, based on the first distance and the second distance, obtaining an adjusted distance;

[0218] The controller 6 is further configured to adjust the positions of the X-ray source and the X-ray sensor based on the adjustment distance within a time period when the horizontal boom 1 rotates from the historical sampling point to the current sampling point.

[0219] As a specific embodiment of the present application, the processor 5 is further used to obtain a target point based on the dental arch curve; the target point includes a point in the plane where the dental arch curve is located with the smallest distance change from each point on the dental arch curve;

[0220] The controller 6 is further configured to adjust the position of the first axis so that the first axis passes through the target point.

[0221] As a specific embodiment of the present application, the processor 5 is further used to obtain a plurality of curve points based on the dental arch curve; the curve point is any point in the dental arch curve;

[0222] And, based on the dental arch curve, a plurality of prediction points are obtained; the prediction points are any points in the plane where the dental arch curve is located;

[0223] and, obtaining a third distance between each predicted point and the plurality of curve points;

[0224] And, based on the plurality of third distances, obtaining a variance corresponding to each prediction point one by one;

[0225] And, based on the variance, the target point is obtained from the multiple prediction points.

[0226] As a specific embodiment of the present application, the processor 5 is further used to obtain, based on the multiple prediction points, a first prediction point, a second prediction point, and a third prediction point that are not collinear; the first prediction point, the second prediction point, and the third prediction point are three prediction points with the smallest variance among the multiple prediction points; and the first variance, the second variance, and the third variance corresponding to the first prediction point, the second prediction point, and the third prediction point are increased in size;

[0227] And, based on the first prediction point, the second prediction point and the third prediction point, obtaining a center point;

[0228] And, based on the center point and the third predicted point, a reference point is obtained; the reference point is any point away from the center point along a first direction; the first direction is from the third predicted point to the center point;

[0229] and, based on the reference point, obtaining a fourth variance;

[0230] And, if the fourth variance satisfies a first preset condition, the target point is obtained based on the first variance and the fourth variance; otherwise, the third prediction point is updated.

[0231] As a specific embodiment of the present application, the processor 5 is further configured to, if the fourth variance is smaller than the first variance, update the third prediction point to any point away from the center point along the first direction;

[0232] And, if the fourth variance is greater than the first variance and less than the third variance, the third prediction point is updated as the reference point;

[0233] And, if the fourth variance is greater than the third variance, the third prediction point is updated to be any point on the line between the center point and the third prediction point.

[0234] As a specific embodiment of the present application, the first preset condition includes: the number of updates of the third prediction point is greater than the first preset value; or the absolute value of the difference between the fourth variance and the target variance is less than the second preset value; the target variance includes the first variance or the average value of the first variance, the second variance and the third variance.

[0235] As a specific embodiment of the present application, the reader 4 is further used to obtain the selected number of the curve points; the selected number is preset;

[0236] The processor 5 is further configured to randomly obtain a plurality of curve points having the same number as the selected number based on the dental arch curve;

[0237] Alternatively, the plurality of curve points include two end points of the dental arch curve; the reader 4 is further used to obtain the selected number of the curve points; the selected number is preset;

[0238] The processor 5 is further configured to obtain a plurality of curve points based on the dental arch curve and the selected number; and the spacing between adjacent curve points is equal.

[0239] The various components (e.g., horizontal boom, X-ray source, and X-ray sensor) in the embodiments of the present application only need to perform simple rotational motion or linear motion, and do not need to perform complex curvilinear motion. Compared with complex curvilinear motion, rotational motion and linear motion are easy to control accurately, and the motion inertia generated by linear motion is small.

[0240] It should be clear that the computer-readable storage media in this application include permanent and non-permanent, removable and non-removable media that can be used to store information by any method or technology. Information can be computer-readable instructions, data structures, modules of programs or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, read-only compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape magnetic disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0241] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0242] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the methods, devices and equipment described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0243] In the several embodiments provided in the embodiments of the present application, it should be understood that the disclosed devices, apparatuses and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the modules is only a logical function division. There may be other division methods in actual implementation, such as multiple modules or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or modules, which can be electrical, mechanical or other forms.

[0244] The modules described as separate components may or may not be physically separated, and the components shown as modules may or may not be physical modules, that is, they may be located in one place or distributed on multiple network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0245] In addition, each functional module in each embodiment of the present application can be integrated into a processing module, or each module can exist physically separately, or two or more modules can be integrated into one module. The above-mentioned integrated module can be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it can be stored in a computer-readable storage medium.

[0246] In the above embodiments, all or part of the embodiments may be implemented by software, hardware, firmware or any combination thereof. When implemented by software, all or part of the embodiments may be implemented in the form of a computer program product.

[0247] The computer program product includes one or more computer instructions. When the computer program is loaded and executed on a computer, the process or function described in the embodiment of the present application is generated in whole or in part. The computer may be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions may be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions may be transmitted from a website site, a computer, a server, or a data center to another website site, a computer, a server, or a data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium may be any available medium that a computer can store or a data storage device such as a server or a data center that includes one or more available media integrated. The available medium may be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk Solid State Disk (SSD)), etc.

[0248] Although the embodiments of the present application have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present application, and that the scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for reconstructing an oral panoramic image, applied to an X-ray imaging system, characterized in that: The X-ray imaging system comprises a horizontal suspension arm (1), an X-ray source (2) arranged at a first end of the horizontal suspension arm (1), and an X-ray sensor (3) arranged at a second end of the horizontal suspension arm; the X-ray source (2) and the X-ray sensor (3) are both capable of moving along the length direction of the horizontal suspension arm (1); the horizontal suspension arm (1) is capable of central rotation around a first axis, the first axis being parallel to the vertical direction; The oral panoramic image reconstruction method comprises: Get the user's dental arch curve; Based on the dental arch curve, obtaining multiple sampling points; Based on the multiple sampling points, the rotation of the horizontal boom (1), the positions of the X-ray source (2) and the X-ray sensor (3) are controlled to obtain perspective views corresponding to each sampling point; Obtain a panoramic view of the oral cavity based on multiple perspective views; After obtaining the dental arch curve of the user, the method further includes: Based on the dental arch curve, a target point is obtained; the target point is a point in the plane where the dental arch curve is located, and the distance change from each point on the dental arch curve is the smallest; adjusting the position of the first axis so that the first axis passes through the target point; After obtaining the perspective view of the historical sampling point, it is only necessary to rotate the horizontal boom (1) around the first axis so that the line between the X-ray source (2) and the X-ray sensor (3) passes through the current sampling point. During this period, it is also necessary to move the X-ray source (2) and the X-ray sensor (3) along the first direction so that the distance between the X-ray source (2) and the X-ray sensor (3) is constant and the distance from the X-ray source (2) to the historical sampling point is equal to the distance from the X-ray source (2) to the current sampling point.

2. The oral panoramic image reconstruction method according to claim 1, characterized in that: The acquiring of a plurality of sampling points based on the dental arch curve comprises: Acquiring a scanning step angle; wherein the scanning step angle is preset; Based on the dental arch curve and the target point, a total scanning angle is acquired; the target point is an intersection point formed by the first axis and the plane where the dental arch curve is located; A plurality of sampling points are acquired based on the scanning step angle and the total scanning angle.

3. The oral panoramic image reconstruction method according to claim 2, characterized in that: The method of controlling the rotation of the horizontal boom (1), the positions of the X-ray source (2) and the X-ray sensor (3) based on the multiple sampling points comprises: Based on the multiple sampling points, a current sampling point and a historical sampling point are acquired; the current sampling point and the historical sampling point are adjacent sampling points; Based on the current sampling point and the target point, acquiring a first distance; Based on the historical sampling points and the target point, acquiring a second distance; Based on the first distance and the second distance, acquiring an adjusted distance; During the time period when the horizontal boom (1) rotates from the historical sampling point to the current sampling point, the positions of the X-ray source and the X-ray sensor are adjusted based on the adjustment distance.

4. The oral panoramic image reconstruction method according to claim 1, characterized in that: The acquiring of the target point based on the dental arch curve comprises: Based on the dental arch curve, a plurality of curve points are obtained; the curve points are any points in the dental arch curve; Based on the dental arch curve, a plurality of prediction points are obtained; the prediction points are any points in the plane where the dental arch curve is located; Obtaining the third distance between each predicted point and the plurality of curve points; Based on the plurality of third distances, obtaining a variance corresponding to each prediction point one by one; Based on the variance, the target point is obtained from the multiple predicted points.

5. The oral panoramic image reconstruction method according to claim 4, characterized in that: The step of acquiring the target point from the plurality of predicted points based on the variance includes: Based on the multiple prediction points, a first prediction point, a second prediction point, and a third prediction point that are not collinear are obtained; the first prediction point, the second prediction point, and the third prediction point are three prediction points with the smallest variance among the multiple prediction points; and the first variance, the second variance, and the third variance corresponding to the first prediction point, the second prediction point, and the third prediction point are increased in size; Acquire a center point based on the first prediction point, the second prediction point, and the third prediction point; Based on the center point and the third predicted point, a reference point is obtained; the reference point is any point away from the center point along a first direction; the first direction is from the third predicted point to the center point; Based on the reference point, obtaining a fourth variance; If the fourth variance satisfies the first preset condition, the target point is acquired based on the first variance and the fourth variance; otherwise, the third prediction point is updated.

6. The oral panoramic image reconstruction method according to claim 5, characterized in that: The updating of the third prediction point comprises: If the fourth variance is smaller than the first variance, the third prediction point is updated to an arbitrary point away from the center point along the first direction; If the fourth variance is greater than the first variance and less than the third variance, the third prediction point is updated as the reference point; If the fourth variance is greater than the third variance, the third prediction point is updated to be any point on the line between the center point and the third prediction point.

7. The oral panoramic image reconstruction method according to claim 5, characterized in that: The first preset condition includes: the update number of the third prediction point is greater than the first preset value; or the absolute value of the difference between the fourth variance and the target variance is less than the second preset value; the target variance includes the first variance or the average value of the first variance, the second variance and the third variance.

8. The oral panoramic image reconstruction method according to claim 4, characterized in that: The acquiring of a plurality of curve points based on the dental arch curve comprises: Obtaining the number of selected curve points; the number of selected points is preset; Based on the dental arch curve, randomly obtaining a plurality of curve points of the same number as the selected number; Alternatively, the multiple curve points include two end points of the dental arch curve; and the acquiring multiple curve points based on the dental arch curve includes: Obtaining the number of selected curve points; the number of selected points is preset; Based on the dental arch curve and the selected number, a plurality of curve points are obtained; and the intervals between adjacent curve points are equal.

9. An X-ray imaging system, characterized in that: include: A horizontal boom (1), wherein the horizontal boom (1) is capable of central rotation around a first axis, wherein the first axis is parallel to a vertical direction; An X-ray source (2) and an X-ray sensor (3); the X-ray source (2) is arranged at a first end of the horizontal suspension arm (1), and the X-ray sensor (3) is arranged at a second end of the horizontal suspension arm (1); the X-ray source and the X-ray sensor are both movable along the length direction of the horizontal suspension arm; A reader (4) for obtaining a dental arch curve of a user; A processor (5) is used to obtain a plurality of sampling points based on the dental arch curve; A controller (6) is used to control the rotation of the horizontal boom, the positions of the X-ray source and the X-ray sensor based on the multiple sampling points, and obtain a perspective view corresponding to each sampling point; The processor (5) is further used to obtain a panoramic image of the oral cavity based on multiple perspective images; The processor (5) is further used to obtain a target point based on the dental arch curve; the target point is a point in the plane where the dental arch curve is located, with the smallest distance change from each point on the dental arch curve; The controller (6) is further used to adjust the position of the first axis so that the first axis passes through the target point; The controller (6) is further configured to, after acquiring the perspective view of the historical sampling point, rotate the horizontal boom (1) around the first axis so that the line between the X-ray source (2) and the X-ray sensor (3) passes through the current sampling point, and during this period, move the X-ray source (2) and the X-ray sensor (3) along the first direction so that the distance between the X-ray source (2) and the X-ray sensor (3) is constant, and the distance from the X-ray source (2) to the historical sampling point is equal to the distance from the X-ray source (2) to the current sampling point.

10. The X-ray imaging system according to claim 9, characterized in that: The reader (4) is also used to obtain a scanning step angle; the scanning step angle is preset; The processor (5) is further used to obtain a total scanning angle based on the dental arch curve and a target point; the target point is an intersection point formed by the first axis and the plane where the dental arch curve is located; And, based on the scanning step angle and the total scanning angle, a plurality of sampling points are acquired.

11. The X-ray imaging system according to claim 10, characterized in that: The reader (4) is further used to obtain a current sampling point and a historical sampling point based on the multiple sampling points; the current sampling point and the historical sampling point are adjacent sampling points; The processor (5) is further configured to obtain a first distance based on the current sampling point and the target point; and, based on the historical sampling point and the target point, acquiring a second distance; and, based on the first distance and the second distance, obtaining an adjusted distance; The controller (6) is also used to adjust the positions of the X-ray source and the X-ray sensor based on the adjustment distance within a time period when the horizontal boom (1) rotates from the historical sampling point to the current sampling point.

12. The X-ray imaging system according to claim 9, characterized in that: The processor (5) is further used to obtain a plurality of curve points based on the dental arch curve; the curve points are any points in the dental arch curve; And, based on the dental arch curve, a plurality of prediction points are obtained; the prediction points are any points in the plane where the dental arch curve is located; and, obtaining a third distance between each predicted point and the plurality of curve points; And, based on the plurality of third distances, obtaining a variance corresponding to each prediction point one by one; And, based on the variance, the target point is obtained from the multiple prediction points.

13. The X-ray imaging system according to claim 12, characterized in that: The processor (5) is further configured to obtain, based on the multiple prediction points, a first prediction point, a second prediction point, and a third prediction point that are not collinear; the first prediction point, the second prediction point, and the third prediction point are three prediction points with the smallest variance among the multiple prediction points; and the first variance, the second variance, and the third variance corresponding to the first prediction point, the second prediction point, and the third prediction point are in increasing order; And, based on the first prediction point, the second prediction point and the third prediction point, obtaining a center point; And, based on the center point and the third predicted point, a reference point is obtained; the reference point is any point away from the center point along a first direction; the first direction is from the third predicted point to the center point; and, based on the reference point, obtaining a fourth variance; And, if the fourth variance satisfies a first preset condition, the target point is obtained based on the first variance and the fourth variance; otherwise, the third prediction point is updated.

14. The X-ray imaging system according to claim 13, characterized in that: The processor (5) is further configured to, if the fourth variance is smaller than the first variance, update the third predicted point to an arbitrary point away from the center point along the first direction; And, if the fourth variance is greater than the first variance and less than the third variance, the third prediction point is updated as the reference point; And, if the fourth variance is greater than the third variance, the third prediction point is updated to be any point on the line between the center point and the third prediction point.

15. The X-ray imaging system according to claim 13, characterized in that: The first preset condition includes: the update number of the third prediction point is greater than the first preset value; or the absolute value of the difference between the fourth variance and the target variance is less than the second preset value; the target variance includes the first variance or the average value of the first variance, the second variance and the third variance.

16. The X-ray imaging system according to claim 12, characterized in that: The reader (4) is also used to obtain the selected number of the curve points; the selected number is preset; The processor (5) is further used to randomly acquire a plurality of curve points having the same number as the selected number based on the dental arch curve; Alternatively, the plurality of curve points include two end points of the dental arch curve; the reader (4) is further used to obtain a selected number of the curve points; the selected number is preset; The processor (5) is further used to obtain a plurality of curve points based on the dental arch curve and the selected number; the spacing between adjacent curve points is equal.

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