Control method for an intraoral scanner, intraoral scanner and storage medium

Abstract

The application relates to the technical field of oral cavity medical instruments, in particular to a control method of an oral cavity scanner, the oral cavity scanner and a storage medium, which can be applied to the examination of oral cavity diseases and oral cavity treatment. The oral cavity scanner comprises a holding part for an operator to hold, an extension part detachably installed on the holding part and used for entering the oral cavity of a subject, the extension part comprises a mirror, the holding part comprises a light projector used for projecting light to the side of the mirror and a camera used for acquiring an image of the side of the mirror, and the control method comprises the following steps: the light projector is caused to project structured light with a first projection area, and the first image is acquired by using the camera, wherein the mirror is entirely within the first projection area; based on the first image, the position and size information of the mirror are determined; based on the position and size information, the light projector is caused to project planar light with a second projection area, and the second image is acquired by using the camera, wherein the second projection area is entirely within the mirror.

Description

Technical Field

[0001] This application relates to the field of oral scanner technology, and in particular to a control method for an oral scanner, an oral scanner and a storage medium, which can be used for the examination of oral diseases. Background Technology

[0002] An oral scanner is a medical device used to digitize the structure of the oral cavity. It is inserted into the patient's mouth and uses optical technology to acquire three-dimensional data of the oral tissues (such as the upper jaw, lower jaw, tongue, gums, etc.). It can be widely used in the examination of oral diseases (e.g., oral malformations) and oral treatment.

[0003] An oral scanner typically includes an opening for light to enter and exit, a mirror positioned at the opening, a light projector that projects light onto the mirror side, and a camera for acquiring an image of the mirror side. During operation, the opening and mirror of the oral scanner are placed inside the patient's mouth. The light projector projects light onto the mirror side, which is reflected by the mirror and then shines through the opening of the extension towards the inner wall of the oral cavity. The light is then reflected by the inner wall of the oral cavity and returns to the mirror through the opening. After being reflected again by the mirror, at least a portion of the light enters the camera, allowing the camera to acquire an image representing the shape of the oral cavity.

[0004] The larger the radial dimension of the reflector, the wider the range of a single image frame that the camera can obtain, which helps the dental scanner obtain high-quality oral images. Therefore, a suitable and as large a reflector as possible can be configured according to the differences in the patient's oral cavity size to balance the patient's experience and high image quality.

[0005] Based on this, a related technology proposes an oral scanner comprising a gripper for the operator to hold and an extension detachably mounted on the gripper for entering the patient's oral cavity. A light projector and a camera are disposed within the gripper, and a reflector is disposed within the extension. Furthermore, the extension is available in various sizes, with different sizes of reflectors, allowing for the use of a larger gripper for patients with large mouths and a smaller gripper for patients with small mouths. Since the reflectors of different sizes in the extensions 2 are different, if the light projector in the gripping part projects light onto the reflectors of different sizes in different extensions with the same projection area, the following problems will occur: If the projection area is relatively small, the area illuminated by the light projector will be the same for different sizes of reflectors. Therefore, even if the extension is replaced with a larger size extension, the image quality will not improve, thus defeating the purpose of configuring extensions of multiple sizes. If the projection area is relatively large, some light will illuminate the outer area of ​​the reflector in the extension, that is, some light will illuminate the inner wall of the extension housing, and some of the light that illuminates the inner wall will be reflected into the camera. This light that illuminates the inner wall of the extension housing and is reflected into the camera will affect the imaging quality of the mouth by the camera, because this kind of light does not act on the inner wall of the mouth as the target of scanning, and interferes with the image clarity of the target of scanning. Therefore, it needs to be removed. Summary of the Invention

[0006] In view of this, this application provides a control method for an oral scanner, an oral scanner, and a storage medium.

[0007] In a first aspect, a control method for an oral scanner is proposed. The oral scanner includes a gripping part for an operator to hold, an extension part detachably mounted on the gripping part and for entering the oral cavity of a subject, the extension part including a reflector, and the gripping part including a light projector for projecting light onto the reflector side and a camera for acquiring an image of the reflector side. The method includes:

[0008] The light projector projects structured light with a first projection area, and the camera acquires a first image, wherein the entire reflector falls within the first projection area;

[0009] Based on the first image, the position and size information of the reflector are determined;

[0010] Based on the position and size information, the light projector projects planar light with a second projection area, and the camera acquires a second image, wherein the entire second projection area falls within the reflector.

[0011] In some possible implementations, the structured light includes:

[0012] A plurality of first stripes of light, when viewed along the optical axis of the light projector, are arranged at equal intervals in a first direction and extend in a second direction, wherein the first direction is perpendicular to the second direction;

[0013] When viewed along the optical axis of the light projector, the plurality of second optical rays are arranged at equal intervals in the second direction and extend in the first direction, with each second optical ray intersecting the plurality of first optical rays.

[0014] In some possible implementations, the structured light comprises a plurality of point lights that are arranged in a two-dimensional matrix and spaced apart from each other when viewed along the optical axis of the light projector.

[0015] In some possible implementations, determining the position and size information of the reflector based on the first image includes:

[0016] From the first image, non-mirror areas corresponding to the shape of the structured light and mirror areas not corresponding to the shape of the structured light are identified, wherein the non-mirror areas surround the mirror areas on the entire circumference.

[0017] The position and size information of the reflector are determined based on the number and position of the structured light units corresponding to the non-mirror area.

[0018] In some possible implementations, the method includes determining the second projection area to be smaller than the determined size information of the reflector before the light projector projects planar light with the second projection area.

[0019] In some possible implementations, determining the position and size information of the reflector based on the number and position of the structural units corresponding to the non-mirror area includes:

[0020] The position of the reflector is determined based on the position of the structural unit corresponding to the non-mirror area;

[0021] The difference between the total number of structured light units in the structured light and the number of structured units corresponding to the non-mirror area is determined as the number of structured light units occupied by the mirror area.

[0022] The projected area of ​​the reflector along the optical axis of the light projector is determined based on the number of structured light units occupied by the mirror area.

[0023] Determining the second projection area as an area smaller than the determined size information of the reflector includes: determining the second projection area as an area smaller than the projected area and entirely falling within the projected area.

[0024] In some possible implementations, the method includes, before causing the light projector to project planar light with a second projection area:

[0025] The second projection area is determined based on the closed outer boundary defined by multiple target structured light units, wherein the boundary of the second projection area coincides with the closed outer boundary, and the multiple target structured light units are the structured light units remaining after removing the structured light units on the periphery from the structured light units occupied by the determined mirror area.

[0026] In some possible implementations, the reflector has a black body disposed around its entire periphery, and the method further includes:

[0027] The light projector projects a second planar light with a third projection area, and the camera acquires a third image, wherein the reflector is entirely within the third projection area;

[0028] Based on the closed black ring pattern in the third image, the second position and size information of the reflector are determined, wherein the black ring pattern corresponds to the black body and does not limit the boundary of the third image;

[0029] Based on the second position and size information, the light projector projects a third planar light with a fourth projection area, and the camera acquires a fourth image, wherein all of the third planar light falls within the reflector.

[0030] Secondly, an oral scanner is proposed, comprising:

[0031] An extension for entering the patient's oral cavity, including a reflector;

[0032] The gripping part, which is gripped by the operator and detachably mounted to the extension, includes a light projector for projecting light onto the side of the reflector and a camera for acquiring an image of the side of the reflector.

[0033] A control device, electrically connected to the light projector and the camera, is configured to perform the method as described in the first aspect.

[0034] Thirdly, a computer storage medium is proposed, characterized in that it comprises:

[0035] memory,

[0036] The processor connected to the memory, and

[0037] Program instructions stored in memory and executable by the processor;

[0038] The processor executes the program instructions to implement the method as described in the first aspect.

[0039] According to the control method for an oral scanner provided in this application, the method can automatically adjust the projection area size of the light projector according to the size of the reflector currently installed in the oral scanner in order to obtain high-quality oral images. Attached Figure Description

[0040] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings of the embodiments will be briefly described below. Obviously, the drawings described below only relate to some embodiments of this application, and are not intended to limit this application.

[0041] Figure 1 This is a schematic diagram of the structure of the oral scanner provided in this application embodiment when it is equipped with a medium-sized extension.

[0042] Figure 2 This is a schematic diagram illustrating the working principle of the oral scanner provided in the embodiments of this application.

[0043] Figure 3 This is a schematic diagram of the structure of the oral scanner provided in this application embodiment when it is equipped with a small extension.

[0044] Figure 4 This is a schematic diagram of the structure of the oral scanner provided in this application embodiment when it is equipped with a large extension.

[0045] Figure 5 This is a flowchart of the control method for an oral scanner provided in an embodiment of this application.

[0046] Figure 6 This is a schematic diagram of structured light provided in an embodiment of this application.

[0047] Figure 7 The embodiments provided in this application are based on Figure 7 A schematic diagram of the first image of the structured light shown.

[0048] Figure 8 This is a schematic diagram of the principle for determining the second projection area provided in the embodiments of this application.

[0049] Figure 9 This is a schematic diagram of structured light provided in an embodiment of this application.

[0050] Figure 10 The embodiments provided in this application are based on Figure 9A schematic diagram of the first image of the structured light shown.

[0051] Figure 11 This is a flowchart of the control method for an oral scanner provided in an embodiment of this application.

[0052] Figure 12 This is a schematic diagram of the third image provided in the embodiments of this application.

[0053] Explanation of reference numerals in the attached figures:

[0054] 100-Oral Scanner;

[0055] 200, 300 - Control methods for dental scanners;

[0056] DR1 - First direction, DR2 - Second direction, DR3 - Optical axis direction of the light projector;

[0057] 1-Gripper, 11-Light projector, 12-Camera;

[0058] 2, 2S, 2M, 2B - extensions, 21 - mirrors, 22 - openings;

[0059] 3-Structured light, 31-Point light, 32-First strip light, 33-Second strip light, 3a-Structured light unit, 3a1-Target structured light unit, 3a2-Structured light unit on the periphery of the structured light unit occupied by the mirror area;

[0060] 4-First image, 41-Non-mirror area, 42-Mirror area, 43-First part of the pattern, 44-Second part of the pattern, 4a-Dot pattern, Cb-Closed outer boundary;

[0061] S1 - First projection area;

[0062] S2 - Second projection area;

[0063] S3 - Third projection area;

[0064] S4 - Third projection area;

[0065] Sp - Projected area;

[0066] 5-Third image, 51-Black ring pattern, 52-First non-black pattern, 53-Second non-black pattern, 51a-Inner periphery of the black ring pattern, 51b-Outer periphery of the black ring pattern;

[0067] 6. Tongue. Detailed Implementation

[0068] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. Based on the described embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. It is understood that, without conflict, some technical means of the various embodiments described herein can be substituted for or combined with each other.

[0069] In the description of this application and the claims, the terms "first," "second," etc., are used only to distinguish the described objects and have no sequential or technical meaning. Therefore, objects specified with "first," "second," etc., may explicitly or implicitly include one or more of those objects. Furthermore, the words "one" or "a" do not indicate a quantity limitation, but rather indicate the presence of at least one, while "multiple" indicates not less than two.

[0070] Figure 1 An oral scanner 100 according to an embodiment of this application is shown, and Figure 2 The working principle of the oral scanner 100 is illustrated. The oral scanner 100 can be used to scan the oral cavity (e.g., the tongue and / or the inner walls of the cheeks) of a subject, such as a patient with oral diseases, to obtain images of the oral cavity (e.g., three-dimensional model images), thereby facilitating the diagnosis of oral diseases by medical personnel. In some embodiments, the oral scanner 100 can further obtain a model of the oral cavity based on the images.

[0071] The oral scanner 100 includes a gripper 1 and an extension 2 detachably mounted on the gripper 1.

[0072] The gripping part 1 includes a gripping part housing (not marked) and a light projector 11 and a camera 12 mounted within the gripping part housing. The gripping part housing defines the shape of the gripping part 1 and is formed into a straight handle shape for easy gripping by the operator. When viewed along the extending direction of the straight handle-shaped gripping part housing, the positions of the camera 12 and the light projector 11 are at least partially offset, such that the camera 12 does not obstruct the optical axis of the light projector 11, and the light projector 11 does not obstruct the optical axis of the camera 12. Therefore, the gripping part 1 is formed relatively thick so that the gripping part housing has a sufficiently large radial space to accommodate the camera 12 and the light projector 11.

[0073] In some embodiments, multiple cameras 12 are configured to easily generate three-dimensional model images of the oral cavity (e.g., the upper or lower jaw). In this case, not only is it required that each camera 12 not obstruct the optical axis of the light projector 11, but these cameras 12 also do not block each other; therefore, the gripper 1 may have a larger radial dimension.

[0074] The extension 2 is detachably mounted to the front end of the gripping part 1 via a locking assembly (not marked), and is formed as a column extending in the same direction as the gripping part 1, gradually tapering away from the gripping part 1. Specifically, the extension 2 includes an extension housing (not marked) and a reflector 21 mounted within the extension housing, wherein the extension housing defines the shape of the extension 2, the reflector 21 is specifically disposed at the front end of the extension housing, and the extension housing has an opening 22 for light to enter and exit at the reflector 21. The mirror surface of the reflector 21 is inclined relative to the optical axis of the light projector 11. In implementation, the light projector 11 in the gripping part 1 projects light toward the reflector 21, while the camera 12 in the gripping part 1 acquires an image from the reflector 21.

[0075] In this embodiment, by forming the extension 2 to gradually taper in the direction away from the gripping part 1, a light transmission space that gradually narrows in the direction away from the gripping part 1 can be obtained inside the extension housing (see [reference]). Figure 2 (Understanding) Because this light transmission space is precisely adapted to the optical axis extension direction of the light projector 11 and the camera 12, it does not obstruct the light projection of the light projector 11 onto the reflector 21, nor does it obstruct the camera 12 from receiving the light from the reflector 21. Advantageously, this design can reduce the radial dimension of the extension 2 so that the extension 2 can smoothly enter the patient's oral cavity wall and be adjusted in position within the oral cavity during use.

[0076] Please see also Figure 1 and Figure 2 During operation, the operator can hold the gripper 1 of the oral scanner 100 and insert the extension including the reflector 21 into the patient's, i.e., the subject's, oral cavity. The light projector 11 projects light towards the reflector 21, and the light, after being reflected by the reflector 21, is directed from the opening 22 of the extension towards the inner wall of the oral cavity. Figure 2 In the image, the inner wall is schematically represented as the tongue surface of the tongue 6. Then, light is reflected (diffuse reflection) from the inner wall of the oral cavity and returns to the reflector 21 through the opening 22. After being reflected by the reflector 21, at least part of the light enters the camera 12, thereby obtaining an image representing the shape of the oral cavity by the camera 12.

[0077] Understandably, the larger the radial dimension of the extension 2, the larger the size of the reflector 21 that can be configured, and the more it helps the camera 12 obtain high-quality oral images. However, a large extension 2 is not suitable for patients with small mouths, such as children or women. Therefore, please refer to... Figure 1 Multiple extensions 2S, 2M, and 2B of different sizes and models can be configured to allow for the selection of the most suitable and largest possible extension 2S, 2M, or 2B for different patients, thus balancing ease of operation, patient experience, and imaging quality. For example, for an adult woman, such as... Figure 1 A medium-sized extension 2M equipped with a medium-sized reflector 21 can be fitted to the gripping part 1; for a child, a small extension 2S equipped with a small-sized reflector 21 can be fitted to the gripping part 1, such as... Figure 3 For an adult male, a large extension 2B equipped with a large reflector 21 can be fitted onto the gripping part 1, such as... Figure 4 Understandably, although the various extensions 2S, 2M, and 2B have different dimensions, their tail ends are equipped with the same locking structure, thus enabling them to be interchangeably engaged with the same handpiece.

[0078] In the description of this application, when it is not necessary to distinguish the size of the extension 2, it is given reference numeral 2; however, when it is intentional to distinguish the size of the extension 2, it is given reference numerals 2S, 2M or 2B accordingly.

[0079] Since the reflectors 21 of the extensions 2S, 2M, and 2B of different sizes are different, if the light projector 11 in the gripping part 1 projects light onto the different-sized reflectors 21 in the extensions 2S, 2M, and 2B with the same projection area, the following problem will occur: if the projection area is relatively small, the area of ​​the reflectors 21 of different sizes illuminated by the light projector 11 will be the same. Therefore, even if the extension 2B is replaced with a larger-sized extension, it will not result in an improvement in image quality, thus losing the advantage of configuring extensions 2S, 2M, and 2B of different sizes. The significance of M and 2B: If the irradiation area is relatively large, some light will illuminate the outer area of ​​the reflector 21 within the extension, that is, some light will illuminate the inner wall of the extension housing, and some of the light illuminating the inner wall will be reflected into the camera 12. This light that illuminates the inner wall of the extension housing and is reflected into the camera 12 will affect the imaging quality of the oral cavity by the camera 12, because this type of light does not act on the inner wall of the oral cavity, which is the target of scanning, and interferes with the imaging clarity of the target of scanning. Therefore, it needs to be removed.

[0080] Based on this, please see Figure 5 and combined Figures 6 to 9This application provides a control method 200 for the aforementioned oral scanner 100. This method 200 automatically adjusts the projection area size of the light projector 11 according to the size of the reflector 21 currently mounted in the oral scanner 100, in order to obtain high-quality oral images. This method 200 includes the following steps S501 to S503:

[0081] S501, the light projector 11 projects structured light 3 with the first projection area S1, and the camera 12 acquires the first image 4, wherein the reflector 21 falls entirely within the first projection area S1.

[0082] In implementation, the projection area of ​​the structured light 3 projected by the light projector 11 can be a relatively large value defaulted to by the system. This default projection area is set as follows: when Figure 1 Each of the three sizes of extensions 2S, 2M, and 2B is installed in the oral scanner 100. The projection area (corresponding to the circumferential boundary of the structured light 3) can completely surround the reflector 21, so that a portion of the structured light 3 is irradiated onto the inner wall of the extensions 2S, 2M, and 2B located on the outer periphery of the reflector 21.

[0083] It should be understood that the structured light 3 projected by the light projector 11, as well as the planar light described later, is typically divergent (e.g., pyramidal), and therefore the projected area is not uniform everywhere. Thus, it is understood that when comparing the projected areas of different projected lights below, it is based on comparisons at the same optical path location (e.g., at the same distance from the light emitter).

[0084] When viewed along the optical axis DR3 of the light projector 11, the individual structured light units 3a in the structured light 3 are arranged in a two-dimensional matrix, and the row spacing and column spacing of the two-dimensional matrix are equal. This design facilitates the easy determination of the position and size of relevant objects (e.g., deformities or tooth defects located on the inner wall of the oral cavity) based on the structured light 3.

[0085] exist Figure 6 In the illustrated embodiment, the structured light 3 projected by the light projector 11 includes a plurality of point lights 31. When viewed along the optical axis DR3 of the light projector 11, the plurality of point lights 31 are arranged in a two-dimensional matrix, spaced apart from each other in a first direction DR1 and a second direction DR2 perpendicular to the optical axis DR3, and the row spacing and column spacing of the two-dimensional matrix are equal. Figure 6 In this context, each point light 31 can be regarded as a structured light unit 3a.

[0086] exist Figure 8In the illustrated embodiment, the structured light 3 projected by the light projector 11 includes a plurality of first stripe lights 32 and a plurality of second stripe lights 33. When viewed along the optical axis DR3 of the light projector 11, the plurality of first stripe lights 32 are arranged at equal intervals in the first direction DR1 and extend in the second direction DR2 perpendicular to the first direction DR1. The plurality of second stripe lights are arranged at equal intervals in the second direction DR2 and extend in the first direction DR1. Each second stripe light 33 intersects with a plurality of first stripe lights 32. Furthermore, the spacing between adjacent first stripe lights 32 and the spacing between adjacent second stripe lights 33 can be the same. Figure 8 In this context, the intersection of any two strip lights can be considered as a structured light unit 3a.

[0087] S502, based on the first image 4, determine the position and size information of the reflector 21.

[0088] Understandably, the portion of structured light 3 projected onto the outside of mirror 21 and in contact with the inner wall of extension 2 will undergo diffuse reflection, thus at least partially reflecting back to camera 12, and generating a first partial pattern 43 in the first image 4 that closely corresponds to the shape of that portion of structured light 3. In contrast, the other portion of structured light 3 projected onto mirror 21 will undergo specular reflection and be emitted from opening 22 to the outside (e.g., the inner wall of the oral cavity). Although a portion of this emitted light (and ambient light) may be reflected back from opening 22 to mirror 21 and thus reflected back to camera 12, the shape of the corresponding second partial pattern 44 in the first image 4 will have a poorer correspondence to the shape of the original structured light 3. Therefore, by analyzing the shape differences between the relevant patterns in the first image 4 and the structured light 3, the position and size information of mirror 21 can be determined.

[0089] Based on this, please review Figure 5 Step S502 may specifically include S502a to S502b:

[0090] S502a, from the first image 4, a non-mirror region 41 corresponding to the shape of the structured light 3 and a mirror region 42 not corresponding to the shape of the structured light 3 are determined, wherein the non-mirror region 41 surrounds the mirror region 42 on the entire circumference.

[0091] S502b determines the position and size information of the reflector 21 based on the number and position of the structural units corresponding to the non-mirror area 41.

[0092] Specifically, S502b may include:

[0093] Based on the position of the structural unit corresponding to the non-mirror area 41, the position (position information) of the reflector 21 is determined;

[0094] The difference between the total number of structure light units 3a in the structure light 3 and the number of structure units corresponding to the non-mirror region 41 is determined as the number of structure light units 3a occupied by the mirror region 42.

[0095] Based on the number of structured light units 3a occupied by the mirror area 42, the projected area Sp (size information) of the reflector 21 along the optical axis direction DR3 of the light projector 11 is determined. Thus, the position and size information of the reflector 21 are obtained.

[0096] For example, in Figure 6 and Figure 7 In the corresponding implementation, the light projector 11 projects a structured light 3 comprising 18*18 matrix point lights 31. In the first image 4, the 6*18 on the upper side, the 4*18 on the lower side, the 8*4 on the left side of the middle, and the 8*3 on the right side of the middle correspond to the shape of the structured light 3 and are non-mirror areas 41. Therefore, the area corresponding to the middle 8*11 point lights 31 or structured light units 3a in the structured light 3 can be determined as the projection area Sp of the mirror area 42 along the optical axis DR3 of the light projector 11, and the position of the reflector 21 can be determined as the position corresponding to these 8*11 point lights 31. It should be understood that since the size and position of the structured light 3 provided by the light projector 11 are known, the aforementioned projection area Sp and position of the reflector 21 can be relative to the relative area of ​​the structured light 3 (e.g., the ratio to the projection area) and the relative position to the circumferential boundary of the structured light 3, respectively, and do not have to be absolute natural values.

[0097] S503, based on position and size information, the light projector 11 projects planar light with a second projection area S2, and the camera 12 acquires a second image, wherein the entire second projection area S2 falls within the reflector 21. Therefore, the entire second projection area S2 also falls within the aforementioned first projection area S1.

[0098] After determining the size and position of the reflector 21 relative to the projected structured light 3, the light projector 11 can project a planar light of the corresponding position and size based on this information, so as to use the planar light to scan the oral cavity.

[0099] If, in step S503, the second projection area S2 of the planar light projected by the light projector 11 is set to be exactly equal to the aforementioned projection area Sp of the reflector 21 along the optical axis direction DR3 of the light projector 11, then the following drawback may exist: See Figures 6 to 8Because there are gaps between the structured light units 3a in the structured light 3, and because there are processing errors, the projected area Sp determined based on the number of structured light units 3a corresponding to the non-mirror area 41 in the first image 4 may be slightly larger than the actual projected area of ​​the reflector 21. This will cause a portion of the planar light to illuminate the outside of the reflector 21, resulting in (but a small amount) diffuse reflection interference from the inner wall of the extension 2. Therefore, before the light projector 11 projects the planar light with the second projection area S2, the second projection area S2 can be determined first, and the area that is smaller than the determined projected area Sp and falls entirely within the projected area Sp can be determined. More specifically, as shown in the figure... Figure 8 As shown, the method for determining the second projection area S2 can be as follows: The second projection area S2 is determined based on the closed outer boundary Cb defined by multiple target structured light units 3a1. The boundary of the second projection area S2 coincides with the aforementioned closed outer boundary Cb. The multiple target structured light units 3a1 are the remaining structured light units 3a after removing the peripheral structured light units 3a from the structured light units 3a occupied by the determined mirror area 42. In this way, it is possible to ensure that all the planar light provided by the light projector 11 falls within the reflector 21, and also to maximize the second projection area S2 of the planar light, thus helping to improve the imaging quality of the oral cavity.

[0100] Next, please see Figure 11 and Figure 12 This application embodiment also provides another control method 300 for the aforementioned oral scanner 100. This method 300 can also automatically adjust the projection area size of the light projector 11 according to the size of the reflector 21 currently mounted in the oral scanner 100, in order to obtain high-quality oral images. In this method 300, for Figure 1 The three sizes of extensions 2S, 2M, and 2B that can be assembled onto the same gripping part 1 all have reflectors 21 designed such that each reflector 21 has a black body disposed around its entire periphery. For example, the black body may be a resin material covering the periphery of the reflector 21. The method 300 includes the following steps S1101 to S1103:

[0101] S1101, the light projector 11 projects the second planar light with the third projection area S3, and the camera 12 acquires the third image 5, wherein the reflector 21 falls entirely within the third projection area S3.

[0102] In implementation, the third projection area S3 of the second planar light initially projected by the light projector 11 can be a relatively large value by system default. This default third projection area S3 is set as follows: when Figure 1Each of the three sizes of extensions 2S, 2M, and 2B is installed in the oral scanner 100. The second projection area S2 (corresponding to the circumferential boundary of the second planar light) can completely surround the reflector 21, so that a portion of the second planar light irradiates the inner wall of the extensions 2S, 2M, and 2B located on the outer periphery of the reflector 21.

[0103] S1102, based on the closed black ring pattern 51 in the third image 5, determine the second position and size information of the reflector 21, wherein the black ring pattern 51 corresponds to a black body and does not define the boundary of the third image 5.

[0104] Understandably, the portion of the second planar light projected onto the outside of the reflector 21 and contacting the inner wall of the extension 2 will undergo diffuse reflection, thus at least partially reflecting back to the camera 12, and generating a first non-black pattern 52 corresponding to this portion of diffusely reflected light in the third image 5; moreover, the other portion of the second planar light projected into the area of ​​the mirror region 42 within the reflector 21 will undergo specular reflection and be emitted from the opening 22 to the outside (e.g., the inner wall of the oral cavity), and a portion of this emitted light (and any ambient light present) will return from the opening 22 based on reflection from the inner wall of the oral cavity. The reflector 21 reflects light back to the camera 12 based on its mirror reflection, thereby generating a second non-black pattern 53 in the third image 5 corresponding to this portion of the mirror-reflected light. In contrast, another portion of the second planar light projected onto the black body around the periphery of the reflector 21 is absorbed by the black body and is not reflected back to the camera 12, generating a black ring pattern 51 in the third image 5 corresponding to the black body. Moreover, this black ring pattern 51 is exactly between the aforementioned first non-black pattern 52 and second non-black pattern 53, that is, the black ring pattern 51 does not define the boundary of the third image 5. Therefore, based on the aforementioned characteristics in the third image 5, the black ring pattern 51 in the third image 5 can be quickly determined using image analysis technology based on computer software, and the position and size information of the reflector 21, i.e., the second position and size information, can be determined based on the position and size of the black ring pattern 51.

[0105] S1103, based on the second position and size information, the light projector 11 projects the third planar light with the fourth projection area, and the camera 12 acquires the fourth image, wherein all the third planar light falls within the reflector 21. Therefore, all the third planar light also falls within the aforementioned third planar light.

[0106] After determining the second position and size information of the reflector 21, the light projector 11 can project a fourth planar light with the corresponding position and size based on this information, so as to use the fourth planar light to scan the oral cavity.

[0107] If, in step S1103, the fourth projection area of ​​the third planar light projected by the light projector 11 is set to correspond to the outer periphery 51b of the black ring pattern in the third image 5, then there may be the following defect: since there is a certain error in the third image 5 itself and in determining the specific position of the black ring pattern 51 from the third image 5 using the software program, the outer periphery 51b of the determined black ring pattern may deviate from the actual outer periphery of the black body. As a result, a portion of the third planar light will illuminate the outer side of the reflector 21 and the black body, resulting in a smaller amount of diffuse reflection interference from the inner wall of the extension 2.

[0108] In view of this, in step S1103 of some embodiments, the boundary of the third planar light can be set to correspond to the inner periphery 51a of the black annular pattern in the third image 5. In this way, it can be better ensured that all the third planar light provided by the light projector 11 falls within the outer periphery of the black body (which is also the outer periphery of the reflector 21), and the boundary size (projection area) of the third planar light can be maximized. Although a small part of the third planar light will be projected onto the black body that is not a mirror structure, since the black body will not produce diffuse reflection light reflected to the camera 12, it will not interfere with the imaging quality of the oral cavity.

[0109] In the aforementioned methods 200 and 300, when the camera 12 acquires an image from the side of the reflector 21, the optical axis direction (corresponding to the shooting direction) and the focal length (corresponding to the shooting range) of the camera 12 can remain fixed.

[0110] Furthermore, methods 200 and 300 are not mutually exclusive. In some embodiments, the control method 300 for the same oral scanner may include either method 200 or method 300. For example, based on the control of the operation keys provided on the gripper 1 of the oral scanner 100, it can be selectively operated in a first control mode and a second control mode, in which the oral scanner 100 is controlled by method 200 in the first control mode and by method 300 in the second control mode.

[0111] According to the above description, this application provides an oral scanner 100, which includes: an extension 2 for entering the oral cavity of a subject and including a reflector 21; a gripping part 1 for being gripped by an operator and detachably installed with the extension 2, and including a light projector 11 for projecting light onto the side of the reflector 21 and a camera 12 for acquiring an image on the side of the reflector 21; and a control device electrically connected to the light projector 11 and the camera 12, configured to perform the above-described method 200 and / or method 300.

[0112] This application also provides a computer storage medium, including: a memory, a processor connected to the memory, and program instructions stored in the memory and executable by the processor. The processor executes the program instructions to implement the methods 200 and / or 300 described above.

Claims

1. A control method for an oral scanner, the oral scanner comprising a gripping part for an operator to hold, an extension part detachably mounted on the gripping part and for entering the oral cavity of a subject, the extension part including a reflector, the gripping part including a light projector for projecting light toward the reflector side, and a camera for acquiring an image of the reflector side, characterized in that, The method includes: The light projector projects structured light with a first projection area, and the camera acquires a first image, wherein the entire reflector falls within the first projection area; Based on the first image, the position and size information of the reflector are determined; Based on the position and size information, the light projector projects planar light with a second projection area, and the camera acquires a second image, wherein the entire second projection area falls within the reflector. The step of determining the position and size information of the reflector based on the first image includes: From the first image, non-mirror areas corresponding to the shape of the structured light and mirror areas not corresponding to the shape of the structured light are identified, wherein the non-mirror areas surround the mirror areas on the entire circumference. The position and size information of the reflector are determined based on the number and position of the structured light units corresponding to the non-mirror area. The step of determining the position and size information of the reflector based on the number and position of the structured light units corresponding to the non-mirror area includes: The position of the reflector is determined based on the position of the structured light unit corresponding to the non-mirror area; The difference between the total number of structured light units in the structured light and the number of structured light units corresponding to the non-mirror area is determined as the number of structured light units occupied by the mirror area. The projected area of ​​the reflector along the optical axis of the light projector is determined based on the number of structured light units occupied by the mirror area.

2. The method according to claim 1, characterized in that, The structured light includes: A plurality of first stripes of light, when viewed along the optical axis of the light projector, are arranged at equal intervals in a first direction and extend in a second direction, wherein the first direction is perpendicular to the second direction; When viewed along the optical axis of the light projector, the plurality of second light rays are arranged at equal intervals in the second direction and extend in the first direction, with each second light ray intersecting the plurality of first light rays.

3. The method according to claim 1, characterized in that, The structured light comprises multiple point lights, which are arranged in a two-dimensional matrix and spaced apart from each other when viewed along the optical axis of the light projector.

4. The method according to claim 1, characterized in that, Before projecting planar light with the light projector at the second projection area, the method includes: determining the second projection area as an area smaller than the projected area and entirely falling within the projected area.

5. The method according to claim 4, characterized in that, Before projecting planar light with the second projection area using the light projector, the method includes: The second projection area is determined based on the closed outer boundary defined by multiple target structured light units, wherein the boundary of the second projection area coincides with the closed outer boundary, and the multiple target structured light units are the structured light units remaining after removing the structured light units on the periphery from the structured light units occupied by the determined mirror area.

6. The method according to claim 1, characterized in that, The reflector has a black body disposed around its entire periphery, and the method further includes: The light projector projects a second planar light with a third projection area, and the camera acquires a third image, wherein the reflector is entirely within the third projection area; Based on the closed black ring pattern in the third image, the second position and size information of the reflector are determined, wherein the black ring pattern corresponds to the black body and does not limit the boundary of the third image; Based on the second position and size information, the light projector projects a third planar light with a fourth projection area, and the camera acquires a fourth image, wherein all of the third planar light falls within the reflector.

7. An oral scanner, characterized in that, include: An extension for entering the patient's oral cavity, including a reflector; The gripping part, which is gripped by the operator and detachably mounted to the extension, includes a light projector for projecting light onto the side of the reflector and a camera for acquiring an image of the side of the reflector. A control device, electrically connected to the light projector and the camera, is configured to perform the method as described in any one of claims 1 to 6.

Images