Auxiliary Scanning Head, Method for Obtaining Three-Dimensional Data within Oral Cavity, and Intraoral Scanner

Abstract

The present application discloses an auxiliary scanning head and a method for acquiring three-dimensional data within the oral cavity, and an intraoral scanner. The auxiliary scanning head is an intraoral scanner used to scan the interior of the oral cavity to obtain three-dimensional data, and can acquire framework data within a large size range of both end surfaces of the entire dental arch at a single time; the scanning head includes: a shell, a first reflector and a second reflector; the first reflector and the second reflector are arranged inside the shell, and the reflective surface of the first reflector and the reflective surface of the second reflector are arranged back to back, and there is a preset angle between them; a first window and a second window corresponding to the first reflector and the second reflector are provided on the surface of the shell, and the first window and the second window are used to emit the reflected light of the first reflector and the second reflector. The present application solves the technical problem that the acquisition of high-precision full dentition data requires the participation of auxiliary high-precision equipment or auxiliary standard parts, which makes the data acquisition process cumbersome.

Description

Technical Field

[0001] The present application relates to the field of three-dimensional scanning, and more specifically, to an auxiliary scanning head, a method for acquiring three-dimensional data within the oral cavity, and an intraoral scanner. Background Art

[0002] An intraoral 3D scanner uses an in-oral optical scanner to directly scan the patient's oral cavity, acquiring 3D topography and color texture information of the surfaces of soft and hard tissues, including teeth, gums, and mucosa. One method of this device utilizes the principle of active structured light triangulation imaging. A digital projection system projects an active light pattern, which is then captured by a camera acquisition system and processed through algorithms for 3D reconstruction and stitching. Due to the confined environment of the oral cavity, the size of the in-oral optical scanner is necessarily limited. This limits the size of the in-oral scanner to less than 30mm, meaning it can only capture images of approximately two teeth at a time. However, the dental industry often requires full-oral data of teeth and gums during design and fabrication. Therefore, it is necessary to stitch these individually captured tooth images together to create a complete 3D spatial data set consistent with the oral interior. Improving scanning and stitching efficiency requires two key approaches: improving the efficiency of individual scans, specifically the time and integrity of each scan. Furthermore, improving the smoothness of the stitching, specifically the success rate and time required.

[0003] The commonly used solution at present is to use auxiliary equipment to perform framework scanning. After obtaining the accuracy of the framework of the entire dental arch, oral scanning is then used for refined supplementary scanning, which not only ensures the accuracy of the entire dental arch but also pursues the details of the data. For example, marker points are attached to the mouth, a scanning rod with marker points is implanted, or a scanning rod with identifiable features is implanted. Auxiliary equipment with a large field of view is used to obtain the positions of each marker point or feature with high precision as framework data. The teeth, gums, and various marker points and features are then directly obtained using an intraoral scanner, because the framework data serves as a reference guide and can ensure the accuracy of the entire dental arch of the intraoral scanning data. However, such auxiliary equipment is often more expensive than an intraoral scanner. Although it meets the accuracy requirements of the entire dental arch for implantation, it is difficult to popularize it in mass clinics and cannot benefit ordinary patients.

[0004] To address the above-mentioned problems, no effective solutions have been proposed so far. Summary of the Invention

[0005] The embodiments of the present application provide an auxiliary scanning head and a method for acquiring three-dimensional data in the oral cavity, and an intraoral scanner, so as to at least solve the technical problem that obtaining high-precision full dentition data requires the participation of auxiliary high-precision equipment or auxiliary standard parts, which makes the data acquisition process cumbersome.

[0006] According to one aspect of an embodiment of the present application, there is provided an auxiliary scanning head, which is an intraoral scanner used for scanning the inside of an oral cavity to obtain three-dimensional data, including: an intraoral scanner used for scanning the inside of an oral cavity to obtain three-dimensional data; wherein the scanning head includes: a shell, a first reflector and a second reflector; the first reflector and the second reflector are arranged inside the shell, and the reflective surface of the first reflector and the reflective surface of the second reflector are arranged back to back, and a preset angle is formed between them; a first window and a second window corresponding to the first reflector and the second reflector are provided on the surface of the shell, and the first window and the second window are used to emit reflected light from the first reflector and the second reflector.

[0007] Optionally, the preset angle is not less than 60 degrees and not greater than 120 degrees, and an edge of one end of the first reflector contacts an edge of one end of the second reflector. Optionally, the contacting end of the first reflector and the second reflector faces a preset direction, the preset directions including: toward the front end of the housing, toward the upper top surface of the housing, toward the lower bottom surface of the housing, and toward the rear end of the housing.

[0008] Optionally, the top plane in the shell is perpendicular to the side surface of the shell.

[0009] Optionally, the shapes of the first reflector and the second reflector include one of the following: a square, a rectangle, a parallelogram, a triangle, and a pentagon.

[0010] Optionally, it further includes: a rotating device, which is arranged inside the shell, and the first reflector and the second reflector are arranged on the rotating device, and as the rotating device rotates, the first reflector or the second reflector is driven to rotate to adjust the preset angle.

[0011] Optionally, it further includes: an angle sensor for detecting the angle between the respective reflection surfaces of the first reflector and the second reflector after rotation.

[0012] According to another aspect of an embodiment of the present application, an intraoral scanner is also provided, comprising the above-mentioned auxiliary scanning head, main scanning head and body, wherein the auxiliary scanning head and the main scanning head can be detachably connected to the body, and an image acquisition device and a light source are provided in the body, wherein the image acquisition device is used to acquire internal images of the oral cavity; and the light source is used to illuminate the interior of the oral cavity.

[0013] According to another aspect of an embodiment of the present application, a method for acquiring three-dimensional data within the oral cavity is also provided, including: acquiring three-dimensional data of a target local area within the oral cavity collected by a three-dimensional scanning device through an auxiliary scanning head and initial three-dimensional data within the oral cavity collected by a main scanning head; using the three-dimensional data of the target local area as standard framework data, adjusting the initial three-dimensional data, and obtaining target three-dimensional data.

[0014] Optionally, the three-dimensional data of the target local area is used as standard framework data, and the initial three-dimensional data is adjusted to obtain target three-dimensional data, including: randomly selecting two point clouds from the three-dimensional data of the target local area and the initial three-dimensional data for the kth sampling splicing, obtaining the relative motion value of the kth sampling splicing and the average distance between the registration point pairs in the point cloud corresponding to the kth sampling splicing, where k is a natural number; the difference between the relative motion value of the kth sampling splicing and the relative motion value obtained by the k-1th sampling splicing plus the average distance between the registration point pairs in the point cloud corresponding to the kth sampling splicing is determined as the objective function; when the objective function meets the preset iteration condition and the relative motion value obtained by the kth sampling splicing meets the preset constraint condition, the relative motion value obtained by the kth sampling splicing is determined as the target relative motion value; and according to the target relative motion value, multiple point clouds in the initial three-dimensional data are spliced to obtain the target three-dimensional data.

[0015] In this embodiment, an auxiliary scanning head and a main scanning head are used in alternating scanning to acquire 3D data of a localized target area within the oral cavity and initial 3D data within the oral cavity. The localized 3D data is then used as standard data to adjust the initial 3D data, yielding high-precision 3D data of the target within the oral cavity. This eliminates the need for auxiliary components to assist in positioning within the oral cavity, thereby simplifying the 3D data acquisition process and resolving the cumbersome data acquisition process associated with the need to label auxiliary components for obtaining high-precision full dentition data. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The drawings that constitute part of this application are used to provide a further understanding of this application. The illustrative embodiments of this application and their descriptions are used to explain this application and do not constitute an improper limitation on this application. In the drawings:

[0017] Figure 1 A schematic cross-sectional view of an auxiliary scanning head structure in the implementation of the present application is shown;

[0018] Figure 2 A schematic structural diagram of an auxiliary scanning head in an embodiment of the present application is shown;

[0019] Figure 3 A schematic cross-sectional view of the structure of a conventional scanning head in the related art is shown;

[0020] Figure 4 A schematic structural diagram of a conventional scanning head in the related art is shown;

[0021] Figure 5 A cross-sectional schematic diagram of an intraoral scanner in an embodiment of the present application is shown;

[0022] Figure 6A schematic cross-sectional view of another auxiliary scanning head structure in the embodiment of the present application is shown;

[0023] Figure 7a A schematic structural diagram of an intraoral scanner equipped with an auxiliary scanning head in an embodiment of the present application is shown;

[0024] Figure 7b A schematic structural diagram of an intraoral scanner equipped with a main scanning head in an embodiment of the present application is shown;

[0025] Figure 8 A schematic diagram of a full dental arch structure in an embodiment of the present application is shown;

[0026] Figure 9 A flow chart of a method for acquiring three-dimensional intraoral data according to the present application is shown;

[0027] The above drawings include the following reference numerals:

[0028] 10. Shell; 11. First reflector; 12. First window; 13. Bracket; 14. Intraoral scanner; 15. Second reflector; 16. Rotating device; 17. Angle sensor; 18. Auxiliary scanning head; 19. Main scanning head; 20. Body. DETAILED DESCRIPTION

[0029] In order to enable those skilled in the art to better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of this application.

[0030] It should be noted that the terms "first", "second", etc. in the specification and claims 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 sequential order. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in a sequence other than those illustrated or described herein. 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 comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0031] In related technologies, an intraoral scanner equipped with a traditional scanning head can directly obtain three-dimensional morphological data of teeth or gums, which can be directly used for processing and restoring teeth to improve the efficiency of medical treatment and reduce the cumulative errors caused by data conversion during the traditional processing process. However, due to the complexity and diversity of the intraoral environment, especially in edentulous cases, it is difficult to obtain good splicing smoothness and high-precision three-dimensional data due to the interference of gingival soft tissue deformation. There are also relevant solutions to control the accuracy of the entire dental arch, such as: implant rods with landmarks, taking impressions as framework data, etc. However, similar solutions require higher-precision auxiliary equipment as a benchmark to improve the accuracy of the entire dental arch, which is more difficult to control costs and increases the difficulty of learning and using equipment.

[0032] The present application provides an auxiliary scanning head, which is used for an intraoral scanner to scan the inside of the oral cavity to obtain three-dimensional data, such as Figure 1 As shown, it includes: a shell 10, a first reflector 11 and a second reflector (not shown in the figure); the first reflector 11 and the second reflector are arranged inside the shell 10, and the reflective surface of the first reflector 11 and the reflective surface of the second reflector are arranged back to back and form a preset angle between them; a first window 12 and a second window (not shown in the figure) corresponding to the first reflector 11 and the second reflector are provided on the surface of the shell 10, and the first window 12 and the second window are used to emit the reflected light of the first reflector 11 and the second reflector. Figure 2 A schematic structural diagram of the auxiliary scanning head is shown.

[0033] It should be noted that the conventional scanning head in the related art only includes one reflector, such as Figure 3 As shown, a conventional scanning head includes: a housing 10, a reflector, the reflector being disposed inside the housing 10, a window corresponding to the reflector being disposed on the surface of the housing 10, and the window being disposed on the top plane of the housing 10. It is understood that a conventional scanning head can only acquire three-dimensional data through a single window. Figure 4 A schematic structural diagram of a conventional scanning head is shown.

[0034] Optionally, the housing 10 may be provided with one or more reflectors in addition to the first reflector 11 and the second reflector.

[0035] The auxiliary scanning head provided in this application can simultaneously obtain three-dimensional data of the ends of both sides of the dental arch in the oral cavity as standard framework data, and adjust the obtained initial three-dimensional data in the oral cavity to improve the accuracy of the three-dimensional data of the entire dentition.

[0036] A specific operation method is as follows: first use a conventional scanning head to obtain the initial three-dimensional data of the oral cavity, and then use the auxiliary scanning head to obtain the three-dimensional data of the target local area, for example: the area at both ends of the entire dental arch in the oral cavity. It is understandable that the auxiliary scanning head can obtain data within a large size range of both end surfaces of the entire dental arch in a single time as standard framework data, replacing the annotation role of auxiliary parts in obtaining three-dimensional data, thereby solving the technical problem that the acquisition of high-precision full dentition data requires auxiliary high-precision equipment, intraoral markers, implanted scanning rods with markers, implanted scanning rods with identifiable features or auxiliary standard parts to participate in the annotation, which makes the data acquisition process cumbersome. And because the auxiliary scanning head has two reflectors, it can obtain data at both ends of the entire dental arch at the same time, making it more referenceable as standard framework data. Another specific operation method is as follows: first use the auxiliary scanning head to obtain the three-dimensional data of the target local area, and then use the conventional scanning head to obtain the initial three-dimensional data of the oral cavity.

[0037] The structural features of the auxiliary scanning head are described in detail below.

[0038] like Figure 5 As shown, the reflective surface of the first reflector 11 and the reflective surface of the second reflector 15 are arranged back to back and form a preset angle between them. The preset angle is not less than 60 degrees and not more than 120 degrees, for example: 60 degrees, 70 degrees, 80 degrees, 90 degrees, 100 degrees, 110 degrees and 120 degrees, and the edge position of one end of the first reflector 11 contacts the edge position of one end of the second reflector 15.

[0039] In some optional embodiments, the edge position of one end and the edge position of one end of the second reflector 15 may not contact each other, but since the scanning head needs to be extended into the oral cavity to obtain three-dimensional data, considering the size of the space inside the oral cavity, the gap between the edge position of the first reflector 11 and the edge position of the second reflector 15 needs to be less than a preset distance. Figure 1 In the embodiment, the first reflector 11 and the second reflector 15 are fixed to the inside of the housing 10 via a bracket 13 fixed to the inside of the housing 10. In an optional manner, one end of the bracket 13 is fixed to the bottom inside the housing 10, and the other end is fixed to the top inside the housing 10. The first reflector 11 and the second reflector 15 are fixed to the top inside the housing 10 via the bracket 13.

[0040] Since the light reflected by the first reflector 11 and the second reflector 15 is emitted from the first window 12 and the second window respectively, it is understood that the direction of the contacting end of the first reflector 11 and the second reflector 15 is not fixed and can be oriented in a predetermined direction, including: toward the front end of the housing 10, toward the top surface of the housing 10, toward the bottom surface of the housing 10, and toward the rear end of the housing 10.

[0041] Among them, the open end connecting the shell 10 and the fuselage 20 is called the rear end, the end where the first reflector 11 and the second reflector 15 are located inside the auxiliary scanning head 18 is called the front end, the side of the shell 10 connected to the bracket 13 is called the lower bottom surface, the upper top surface is opposite to the lower bottom surface, and the remaining two side surfaces are the left and right side surfaces.

[0042] Figure 1 The inner plane of the front end of the shell 10 is at a preset angle to the inner side surface of the shell 10. In some optional embodiments, the top plane of the shell 10 is perpendicular to the side surface of the shell 10.

[0043] Light reflected by the first and second reflectors 11, 15 is emitted through the first and second windows 12 and 15. The shapes of the first and second reflectors 11, 15 can be set to any desired shape, such as a square, rectangle, parallelogram, triangle, or pentagon. Setting the reflector shapes to rectangles, squares, or pentagons increases the reflective area of the lens, thereby improving the efficiency of acquiring three-dimensional data.

[0044] The first reflector 11 and the second reflector 15 may have the same or different sizes. The first reflector 11 and the second reflector 15 may have the same or different shapes.

[0045] Figure 6 Another auxiliary scanning head is shown, in which a rotating device 16 is fixed on the top bracket 13 inside the shell 10, and the first reflector 11 and the second reflector 15 are set on the rotating device 16. As the rotating device 16 rotates, the first reflector 11 or the second reflector 15 is driven to rotate to adjust the preset angle.

[0046] An angle sensor 17 is also fixed inside the housing 10 for detecting the angle between the respective reflection surfaces of the first reflector 11 and the second reflector 15 after they are rotated.

[0047] The present application also proposes an intraoral scanner, such as Figure 7a 、 7b As shown, it includes the above-mentioned auxiliary scanning head 18, main scanning head 19 and body 20. The auxiliary scanning head 18 and the main scanning head 19 can be detachably arranged on the body 20. An image acquisition device and a light source are arranged in the body 20. The image acquisition device is used to acquire internal images of the oral cavity; the light source is used to illuminate the inside of the oral cavity.

[0048] It should be noted that the main scanning head 19 can be Figure 3 and Figure 4 The conventional scanning head shown may also be other scanning heads that can acquire data of each tooth in the mouth.

[0049] There may be only one set of image acquisition device and light source in the fuselage 20 , and the auxiliary scanning head 18 and the main scanning head 19 may share the set of image acquisition device and light source in the fuselage 20 .

[0050] In addition, the body 20 can be provided with two sets of image acquisition devices and light sources, and the auxiliary scanning head 18 and the main scanning head 19 can correspond to the two sets of image acquisition devices and light sources in the body 20 respectively. When replacing the auxiliary scanning head 18 and the main scanning head 19, they can be switched using a switch on the body 20.

[0051] Figure 8 A schematic diagram of the entire dental arch is shown. Figure 8 As shown, the solid line part (the inner surface and part of the upper surface of the two teeth at the end of both sides of the entire dental arch) is the part scanned by the auxiliary scanning head 18, and the dotted line part (the part other than the part scanned by the auxiliary scanning head 18) is the part scanned by the main scanning head 19. In actual application scenarios, the auxiliary scanning head 18 can be used to scan the upper dental arch and the lower dental arch to directly obtain the three-dimensional data of the inner surface and part of the upper surface of the two teeth at the end of the upper dental arch and the lower dental arch, and then the main scanning head 19 is used to obtain the three-dimensional data of the rest of the upper dental arch and the lower dental arch.

[0052] The image acquisition device may include a color separation prism and two cameras. The color separation prism splits the structured light pattern, collects one of the split light rays through one of the cameras, and collects one of the split light rays through another camera, and uses the two collected light rays as two-dimensional scanning data of the dental arch. Therefore, in the embodiment of the present disclosure, when the oral cavity is scanned using the above-mentioned intraoral scanner, the preset light rays are uniformly processed by the collimated light device, so that the preset light rays can be uniformed at the energy level to obtain a higher light energy utilization rate and uniform illumination of a larger area, which is conducive to projecting uniform preset light rays, avoiding the occurrence of diffraction spots, and improving light utilization. In addition, by collecting the multiple structured light patterns after splitting through different cameras, the structured light patterns after splitting can be distinguished, mutual interference between different structured light patterns can be avoided, and the accuracy of the scanning data can be improved.

[0053] The present application also proposes a method for obtaining three-dimensional data in the oral cavity, such as Figure 9 As shown, the method includes:

[0054] Step S802, acquiring three-dimensional data of a target local area in the oral cavity collected by a three-dimensional scanning device through an auxiliary scanning head and initial three-dimensional data of the oral cavity collected by a main scanning head;

[0055] Step S804 : Using the three-dimensional data of the target local area as standard framework data, adjusting the initial three-dimensional data to obtain target three-dimensional data.

[0056] It should be noted that the steps shown in the flowcharts of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and that, although a logical order is shown in the flowcharts, in some cases, the steps shown or described can be executed in an order different from that shown here.

[0057] The above method adopts the method of alternating scanning of the auxiliary scanning head and the main scanning head to respectively obtain the three-dimensional data of the local target area in the oral cavity and the initial three-dimensional data in the oral cavity. Since the three-dimensional data of the ends of the full dental arch in a large range can be equivalent to the accuracy of the single-frame three-dimensional data, and the auxiliary scanning head can obtain the framework data within a large size range of the two end surfaces of the full dental arch at a single time, the local three-dimensional data of the target can be used as the standard framework data to adjust the initial three-dimensional data to obtain high-precision three-dimensional data of the target in the oral cavity. The purpose of eliminating the auxiliary positioning of the auxiliary components in the oral cavity is achieved, thereby achieving the technical effect of simplifying the three-dimensional data acquisition process, and further solving the technical problem that the acquisition of high-precision full dentition data requires the participation of auxiliary high-precision equipment or auxiliary standard parts in the labeling, which makes the data acquisition process cumbersome. Taking the intraoral scanner 14 proposed in this application as an example, the auxiliary scanning head is first set on the intraoral scanner to obtain the three-dimensional data of the local target area in the oral cavity, for example: the areas at the ends of the full dental arch in the oral cavity, as standard framework data;

[0058] Then, a main scanning head is mounted on the intraoral scanner to obtain initial three-dimensional data of the oral cavity, which includes multiple frames of local three-dimensional data.

[0059] Two point clouds are randomly selected from the three-dimensional data of the target local area and the initial three-dimensional data for the k-th sampling splicing, and the relative motion value of the k-th sampling splicing and the average distance between the registration point pairs in the point cloud corresponding to the k-th sampling splicing are obtained, where k is a natural number; the difference between the relative motion value of the k-th sampling splicing and the relative motion value obtained by the k-1-th sampling splicing plus the average distance between the registration point pairs in the point cloud corresponding to the k-th sampling splicing is determined as the objective function; when the objective function meets the preset iteration condition and the relative motion value obtained by the k-th sampling splicing meets the preset constraint condition, the relative motion value obtained by the k-th sampling splicing is determined as the target relative motion value; according to the target relative motion value, multiple point clouds in the initial three-dimensional data are spliced to obtain the target three-dimensional data.

[0060] Specifically, taking k as 2 as an example, the initial three-dimensional data is sampled and spliced for the second time to obtain the first relative motion value, and the initial three-dimensional data and the standard three-dimensional data of the target local area are sampled and spliced to obtain the second relative motion value. The first relative motion value and the second relative motion value constitute the relative motion value of the second sampling splicing; the first distance value between the registration point pairs in the multi-frame local three-dimensional data of the sampled splicing is calculated, and the difference between the relative motion value of the second sampling splicing and the relative motion value obtained by the first sampling splicing is added to the average distance between the registration point pairs in the point cloud corresponding to the second sampling splicing to determine the objective function.

[0061] In some optional embodiments, the rotation and translation matrix of the sampled local three-dimensional data can be calculated based on the spatial relationship of the sampled and spliced initial three-dimensional data, and then the first relative motion value can be determined; the second relative motion value can be determined based on the rotation and translation matrix of the sampled and spliced initial three-dimensional data and the sampled target local standard three-dimensional data, and the relative motion value is composed of the first relative motion value and the second relative motion value.

[0062] In the embodiment of the present disclosure, in the process of sampling and splicing the initial three-dimensional data and sampling and splicing the initial three-dimensional data and the standard three-dimensional data obtained by the auxiliary scanning head, the visual constraint expression equation can be generated based on the rotation angle and rotation axis of the initial three-dimensional data and the standard three-dimensional data obtained by the auxiliary scanning head from the previous perspective to the current perspective, and a weight matrix can be constructed based on the low-rank sparse matrix constructed based on the initial value of the relative motion of the registration point pair at any two perspectives and the translation vector and Cauchy weight function in the rotation and translation matrix based on the registration point pair at any two perspectives. According to the visual constraint expression equation, the low-rank sparse matrix and the weight matrix, a mathematical model of the global motion optimization problem is constructed. Further, the mathematical model of the global motion optimization problem is processed to obtain an optimization problem expression, and the optimization problem expression is solved to obtain the relative motion value of the current sampling splicing. Optionally, the mathematical model of the global motion optimization problem can be convexly relaxed to obtain the optimization problem expression, and the optimization problem expression can be solved using the Lagrange multiplier method to obtain the relative motion value of the current sampling splicing.

[0063] The objective function is determined by adding the difference between the relative motion value of the k-th sampling splicing and the relative motion value obtained by the k-1-th sampling splicing and the average distance between the registration point pairs in the point cloud corresponding to the k-th sampling splicing.

[0064] It should be noted that in the embodiment of the present disclosure, the initial value of the relative motion can be the initial relative posture between the registration point pairs composed of local three-dimensional data, and the initial relative posture between the registration point pairs composed of local three-dimensional data and standard three-dimensional data of auxiliary parts.

[0065] Based on the above description, the expression of the global optimization energy function is:

[0066] E=▽E(i,j)+∑D(u,v)

[0067] Where E refers to the global optimization energy function, ▽E(i,j) refers to the difference between the relative motion value of the registration point pair obtained in the current splicing and the relative motion value obtained in the previous splicing, i and j are two perspectives, ∑D(u,v) refers to the average distance obtained in the current splicing, and u and v are the serial position expressions of all the registration point pairs in the dental arch.

[0068] The Euclidean distance between the registration point pairs in the initial three-dimensional data of the sampled splicing is used as the first distance, and the Euclidean distance between the registration point pairs in the initial three-dimensional data of the sampled splicing and the target local three-dimensional data is calculated, and the Euclidean distance is used as the second distance. The average distance value is formed by the average sum of the first distance value and the second distance value.

[0069] After constructing the objective function, it can be determined whether the objective function meets the iteration stop condition and whether the relative motion value obtained by the current splicing meets the perspective constraint condition. If the objective function meets the iteration stop condition and the relative motion value obtained by the current splicing meets the perspective constraint condition, the relative motion value obtained by the current splicing is used as the relative motion target value.

[0070] It should be further explained that the iteration stop condition includes a preset threshold value, and the viewing angle constraint condition includes a preset relative motion value;

[0071] In some embodiments of the present application, when the value of the target quantity function is less than or equal to a preset threshold and the relative motion value satisfies a preset relative motion relationship, it is determined that the target function satisfies the iteration stop condition and the relative motion value currently obtained by splicing satisfies the perspective constraint condition.

[0072] The preset threshold may be a preset value used to determine whether the global optimization energy function satisfies the iteration stop condition, for example, 0.01 or 0.03.

[0073] The preset relative motion relationship can be used to determine whether the relative motion value obtained by the current splicing is stable. Specifically, the preset relative motion relationship can indicate that the rotation and translation matrices between the local 3D data of adjacent frames are less than or equal to a preset value, and that the rotation and translation matrices between the currently spliced multiple frames of local 3D data and the standard 3D data of the auxiliary component are less than or equal to a preset value. Optionally, the preset relative motion relationship can be determined based on the rotation angle and rotation axis of the transformation from the perspective of the previous splicing to the perspective of the current splicing.

[0074] After obtaining the relative motion target value, the global motion target value of each perspective point cloud can be determined based on the relative motion target value, and all multi-frame local three-dimensional data can be spliced together according to the global motion target value to obtain the overall three-dimensional data of the oral cavity, that is, the target oral cavity data.

[0075] In the above embodiments of the present application, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, please refer to the relevant description of other embodiments.

[0076] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. Among them, the device embodiments described above are only exemplary. For example, the division of units can be a logical function division. In actual implementation, there may be other division methods, such as multiple units 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 through some interfaces, indirect coupling or communication connection of units or modules, which can be electrical or other forms.

[0077] Units described as separate components may or may not be physically separate, and components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple units. Some or all of the units may be selected to achieve the purpose of the present embodiment according to actual needs.

[0078] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0079] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application is essentially or the part that contributes to the prior art or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for enabling a computer device (which can be a personal computer, server or network device, etc.) to execute all or part of the steps of the various embodiments of the present application. The aforementioned storage medium includes: U disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), mobile hard disk, magnetic disk or optical disk and other media that can store program code.

[0080] The above is only a preferred embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present application. These improvements and modifications should also be regarded as the scope of protection of the present application.

Claims

1. An auxiliary scanning head, characterized in that: An intraoral scanner for scanning the interior of an oral cavity to obtain three-dimensional data; wherein the scanning head comprises: a housing, a first reflector and a second reflector; The first reflector and the second reflector are arranged inside the housing, and the reflective surface of the first reflector and the reflective surface of the second reflector are arranged back to back and form a preset angle between them; A first window and a second window corresponding to the first reflector and the second reflector are provided on the surface of the shell, and the first window and the second window are used to emit the reflected light of the first reflector and the second reflector.

2. The scanning head according to claim 1, wherein: The preset angle is not less than 60 degrees and not greater than 120 degrees, and an edge position of one end of the first reflector contacts an edge position of one end of the second reflector.

3. The scanning head according to claim 1, wherein: One end of the first reflector and the second reflector that contacts each other faces a preset direction, and the preset direction includes: toward the front end of the shell, toward the upper top surface of the shell, toward the lower bottom surface of the shell, and toward the rear end of the shell.

4. The scanning head according to claim 1, wherein: The top and bottom end planes of the shell are perpendicular to the side surfaces of the shell.

5. The scanning head according to claim 1, wherein: The shapes of the first reflector and the second reflector include one of the following: a square, a rectangle, a parallelogram, a triangle, and a pentagon.

6. The scanning head according to claim 3, wherein: Also includes: The rotating device is arranged inside the shell, and the first reflector and the second reflector are arranged on the rotating device. As the rotating device rotates, the first reflector or the second reflector is driven to rotate to adjust the preset angle.

7. The scanning head according to claim 6, wherein: Also includes: The angle sensor is used to detect the angle between the respective reflection surfaces of the first reflector and the second reflector after rotation.

8. An intraoral scanner, characterized in that: The invention comprises the auxiliary scanning head, the main scanning head and the main body according to any one of claims 1 to 7, wherein the auxiliary scanning head and the main scanning head are detachably connected to the main body, and an image acquisition device and a light source are provided in the main body, wherein the image acquisition device is used to acquire an internal image of the oral cavity; and the light source is used to illuminate the interior of the oral cavity.

9. A method for acquiring three-dimensional data in an oral cavity, characterized in that: The method includes: Acquire three-dimensional data of a target local area in the oral cavity collected by a three-dimensional scanning device through an auxiliary scanning head and initial three-dimensional data of the oral cavity collected by a main scanning head; Using the three-dimensional data of the target local area as standard framework data, adjusting the initial three-dimensional data to obtain target three-dimensional data; The three-dimensional data of the target local area is used as the standard framework data, and the initial three-dimensional data is adjusted to obtain the target three-dimensional data, including: Randomly select two point clouds from the three-dimensional data of the target local area and the initial three-dimensional data for k-th sampling and splicing, and obtain the relative motion value of the k-th sampling and splicing and the average distance between the registration point pairs in the point cloud corresponding to the k-th sampling and splicing, where k is a natural number; The objective function is determined by adding the difference between the relative motion value of the k-th sampling splicing and the relative motion value obtained by the k-1-th sampling splicing and the average distance between the registration point pairs in the point cloud corresponding to the k-th sampling splicing; When the objective function satisfies a preset iteration condition and the relative motion value obtained by the k-th sampling splicing satisfies a preset constraint condition, determining the relative motion value obtained by the k-th sampling splicing as a target relative motion value; The target three-dimensional data is obtained by splicing multiple point clouds in the initial three-dimensional data according to the target relative motion value.

Images