Device and method for registering a camera with a CT coordinate system in oral implant surgery

Abstract

The application provides a device and method for camera and CT coordinate system registration in oral implant surgery, the device comprising: a tooth socket, a probe, a U-shaped groove with a scribe groove, an infrared binocular camera, the method comprising: obtaining an oral CBCT image; preparing the device and system; calibrating the probe tip position; obtaining a scribe groove point cloud and registering with the U-shaped groove; and performing registration of the infrared binocular camera coordinate system and the CT coordinate system. The application replaces the original registration point by planning multiple curves on the U-shaped groove, omits the process of lifting the hand and moving to the next registration point after selecting a registration point, simplifies the point collection process, optimizes the user interaction mode, and reduces the operation difficulty. In addition, compared with collecting multiple points, the method provided by the application has fewer operation times but more overall collected points, which makes the registration accuracy better and has higher practicability in clinical application.

Description

Technical Field

[0001] This invention relates to the field of dental implant surgery, and more specifically to a device and method for calibrating a camera with a CT coordinate system during dental implant surgery. Background Technology

[0002] With the rapid development of industrial robot technology, surgical robots have become an important research direction in the field of medical surgery. Surgical robots not only make surgical outcomes more precise but also reduce the learning costs for doctors, standardizing and simplifying the surgical process. Meanwhile, dental implant technology has also developed rapidly in recent years, and dental implant surgery has become the mainstream treatment for tooth loss and restoration. Research on surgical robots for dental implants has also become a hot research trend.

[0003] In existing technologies, the registration method between the CT coordinate system and the camera coordinate system in dental implant surgery involves wearing a U-shaped slot in the patient's mouth to select some registration points, taking CT images, and then using a probe during the operation to click on these registration points to obtain the coordinates of these points under the camera. Point cloud registration is then performed by comparing the coordinates of these points in the CT coordinate system with the coordinates of these points in the camera coordinate system acquired during the operation, thus obtaining their transformation matrix and determining the positional relationship between the two coordinate systems. However, this registration method requires ensuring that the angle between the probe and the camera is within a reasonable range when clicking on each registration point, and that the registration points are accurately aligned. Furthermore, there are many registration points, making the operation cumbersome. Summary of the Invention

[0004] To address the problems of cumbersome steps and inconvenient operation in existing methods for calibrating the CT coordinate system and camera coordinate system in dental implant surgery, as described in the background section, this invention provides a device and method for calibrating the camera and CT coordinate system in dental implant surgery. This method simplifies the acquisition process, optimizes user interaction, reduces operational difficulty, and achieves higher calibration accuracy.

[0005] This invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a device for aligning a camera with a CT coordinate system during dental implant surgery. The device includes: an alveolar fossa, a probe, a U-shaped groove with a scribing groove, and an infrared binocular camera.

[0007] The probe head is equipped with a reflective ball as a first visual marker, which can be used by the infrared binocular camera to identify its three-dimensional position. The probe tip is cone-shaped.

[0008] The surface of the U-shaped groove with scribing grooves is provided with multiple scribing grooves for scribing interaction with the probe;

[0009] The infrared binocular camera includes two lenses, left and right, serving as a visual navigator. It also has a rapid point-collecting and recording function, capable of continuously recording the coordinate set of visual markers over a period of time in extremely short time intervals.

[0010] Secondly, the present invention also provides a method for registering a camera with a CT coordinate system during dental implant surgery, comprising the following steps:

[0011] Acquire oral CBCT images;

[0012] Equipment and system preparation;

[0013] The position of the probe tip is calibrated;

[0014] Obtain the point cloud of the scribing groove and register it with the U-shaped groove;

[0015] Perform registration between the infrared binocular camera coordinate system and the CT coordinate system.

[0016] Furthermore, acquiring oral CBCT images includes: taking CBCT images after the patient wears the U-shaped brace;

[0017] Perform 3D modeling to obtain the relative positional relationship between the U-shaped groove and the oral CT model, denoted as . .

[0018] Furthermore, the preparation of the device and system includes: activating the infrared binocular camera, moving the probe around the patient's oral cavity and the U-shaped groove, and ensuring that the infrared binocular camera can stably identify the first visual marker on the probe.

[0019] Further, calibrating the position of the probe tip includes:

[0020] Establish an infrared binocular camera coordinate system: The infrared binocular camera coordinate system XYZ is centered on the left eye of the camera, with the horizontal axis parallel to the camera surface as the X-axis and the axis perpendicular to the camera surface and outward as the Z-axis.

[0021] The probe tip is brought into contact with a point with defined coordinates within the calibration space of the infrared binocular camera. The coordinates of this point are the coordinates of the probe tip in the coordinate system of the infrared binocular camera at the current position. ;

[0022] The current coordinates of the three reflective spheres in the infrared binocular camera coordinate system are as follows: , and ;

[0023] Establish probe coordinate system In the probe coordinate system, the relative positional relationship between the first visual marker and the probe tip can be determined. And satisfy:

[0024]

[0025] As the probe moves, the positions of the first visual marker and the probe tip change, but their relative positions remain the same. It remains unchanged.

[0026] Further, the step of acquiring the point cloud of the scribing groove and registering it with the U-shaped groove includes:

[0027] Place the probe tip at one end of any groove on the U-shaped groove to begin drawing a line, and start the sampling and recording function of the infrared binocular camera.

[0028] After tracing the entire groove line with the probe, stop the point recording to obtain a set of reflective spheres in the infrared camera coordinate system. , and The set of point locations;

[0029] According to the transformation relationship The coordinate system of the infrared binocular camera was calculated to obtain a set of underlined grooves. A set of points;

[0030] Establish a U-shaped groove coordinate system to obtain the set P of point clouds within the scribed groove of the U-shaped groove in the U-shaped groove coordinate system;

[0031] Compare set P with the point cloud set in the infrared camera coordinate system. Correspondingly, calculate the transformation matrix between the infrared binocular camera coordinate system and the U-shaped groove coordinate system. ,satisfy:

[0032]

[0033] Furthermore, the registration of the infrared binocular camera coordinate system with the CT coordinate system includes:

[0034] Based on the transformation relationship between the U-shaped groove coordinate system and the CT coordinate system The transformation relationship between the infrared camera coordinate system and the U-shaped groove coordinate system The registration transformation relationship T between the infrared camera coordinate system and the CT coordinate system is obtained, satisfying:

[0035]

[0036] Determine if the registration accuracy meets the standard. If it does not, re-mark the U-groove and re-register; if it meets the standard, the registration is complete.

[0037] Current coordinate system registration in dental implant surgery involves acquiring registration points on the U-shaped groove. However, because these registration points are scattered and difficult to select, this method is inefficient. This invention replaces the traditional registration points by planning multiple curves on the U-shaped groove, eliminating the need to move to the next point after selection. This simplifies the point acquisition process, optimizes user interaction, and reduces operational difficulty. Furthermore, compared to acquiring multiple points, the method provided by this invention requires fewer operations but acquires a greater number of points, resulting in better registration accuracy and greater clinical applicability. Attached Figure Description

[0038] The features, advantages and technical effects of exemplary embodiments of the present invention will now be described with reference to the accompanying drawings.

[0039] Figure 1 This is a schematic diagram of the U-groove registration operation provided in an embodiment of the present invention;

[0040] Figure 2 This is a schematic diagram of a U-shaped groove structure with scribed grooves provided in an embodiment of the present invention;

[0041] Figure 3 This is a schematic diagram of an infrared binocular camera provided in an embodiment of the present invention;

[0042] Figure 4 This is a schematic diagram of the registration method between the infrared binocular camera coordinate system and the CT coordinate system in dental implant surgery provided in this embodiment of the invention.

[0043] Explanation of reference numerals in the attached diagram: 1. Alveolar groove; 2. Probe; 3. U-shaped groove with scribe lines; 4. Infrared binocular camera; 201. Reflector ball; 202. Probe tip. Detailed Implementation

[0044] The features and exemplary embodiments of various aspects of this disclosure will now be described in detail. To make the objectives, technical solutions, and advantages of this disclosure clearer, the disclosure will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are intended to explain this disclosure only and not to limit it. For those skilled in the art, this disclosure can be implemented without some of these specific details. The following description of the embodiments is merely to provide a better understanding of this disclosure by illustrating examples.

[0045] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0046] To better understand the present invention, the apparatus and method of the present invention will be described in detail below with reference to the accompanying drawings.

[0047] like Figure 1 , Figure 2 , Figure 3 As shown, the present invention provides a device for aligning a camera with a CT coordinate system during dental implant surgery. The device includes: an alveolar 1, a probe 2, a U-shaped groove with a scribing groove 3, and an infrared binocular camera 4.

[0048] The probe 2 has a reflective ball 201 at its head, which serves as a first visual marker and can be used by the infrared binocular camera 4 to identify its three-dimensional position. The probe end 202 is cone-shaped.

[0049] As an alternative implementation, the head of the probe 2 may also use a reflector as a first visual marker, and the end of the probe 2 may also adopt other shapes to achieve the same technical effect.

[0050] like Figure 2 As shown, the surface of the U-shaped groove 3 with scribing grooves is provided with 5 scribing grooves for scribing interaction with the probe 2;

[0051] like Figure 3 As shown, the infrared binocular camera 4 includes two lenses, left and right, serving as a visual navigator. The infrared binocular camera 4 also has a rapid point recording function, which can continuously record the coordinate set of visual markers over a period of time in a very short time interval.

[0052] Secondly, the present invention also provides a method for registering a camera with a CT coordinate system during dental implant surgery, comprising the following steps:

[0053] S101, acquire oral CBCT images;

[0054] S102, Equipment and System Preparation;

[0055] S103, calibrate the position of the probe tip 202;

[0056] S104, Obtain the point cloud of the scribing groove and register it with the U-shaped groove 3;

[0057] S105 performs registration between the infrared binocular camera coordinate system and the CT coordinate system.

[0058] Furthermore, the acquisition of oral CBCT images described in S101 includes: taking CBCT images after the patient wears the U-shaped groove 3;

[0059] Three-dimensional modeling was performed to obtain the relative positional relationship between the U-shaped groove 3 and the oral CT model, denoted as... .

[0060] Furthermore, the device and system preparation in S102 includes: activating the infrared binocular camera 4, moving the probe 2 around the patient's oral cavity and the U-shaped groove 3, and ensuring that the infrared binocular camera 4 can stably identify the first visual marker on the probe 2.

[0061] Further, the calibration of the probe tip position in S103 includes:

[0062] Establish an infrared binocular camera coordinate system: The infrared binocular camera coordinate system XYZ is centered on the left eye of the camera, with the horizontal axis parallel to the camera surface as the X-axis and the axis perpendicular to the camera surface and outward as the Z-axis.

[0063] The probe tip 202 is brought into contact with a point with defined coordinates within the calibration space of the infrared binocular camera 1. The coordinates of this point are the coordinates of the probe tip 202 in the coordinate system of the infrared binocular camera at the current position. ;

[0064] The current coordinates of the three reflective spheres 201 in the infrared binocular camera coordinate system are as follows: , and ;

[0065] Establish probe coordinate system In the probe coordinate system, the relative positional relationship between the first visual marker and the probe tip 202 can be determined. And satisfy:

[0066]

[0067] When the probe 2 moves, the positions of the first visual marker and the probe tip 202 change, but their relative positional relationship remains the same. It remains unchanged.

[0068] Further, the step S104 of obtaining the point cloud of the scribing groove and registering it with the U-shaped groove includes:

[0069] Place the probe tip at one end of any groove on the U-shaped groove to begin drawing a line, and start the sampling and recording function of the infrared binocular camera.

[0070] After using the probe 2 to scribble a line across the entire groove, stop the point recording and obtain a set of reflective spheres in the infrared camera coordinate system. , and The set of point locations;

[0071] According to the transformation relationship The coordinate system of the infrared binocular camera was calculated to obtain a set of underlined grooves. A set of points;

[0072] Establish a U-shaped groove coordinate system to obtain the set P of point clouds within the scribed groove of the U-shaped groove in the U-shaped groove coordinate system;

[0073] Compare set P with the point cloud set in the infrared camera coordinate system. Correspondingly, calculate the transformation matrix between the infrared binocular camera coordinate system and the U-shaped groove coordinate system. ,satisfy:

[0074]

[0075] Furthermore, the registration of the infrared binocular camera coordinate system and the CT coordinate system described in S105 includes:

[0076] Based on the transformation relationship between the U-shaped groove coordinate system and the CT coordinate system The transformation relationship between the infrared camera coordinate system and the U-shaped groove coordinate system The registration transformation relationship T between the infrared camera coordinate system and the CT coordinate system is obtained, satisfying:

[0077]

[0078] Determine if the registration accuracy meets the standard. If it does not, re-mark the U-groove and re-register; if it meets the standard, the registration is complete.

[0079] Current coordinate system registration in dental implant surgery involves acquiring registration points on the U-shaped groove. However, because these registration points are scattered and difficult to select, this method is inefficient. This invention replaces the traditional registration points by planning multiple curves on the U-shaped groove, eliminating the need to move to the next point after selection. This simplifies the point acquisition process, optimizes user interaction, and reduces operational difficulty. Furthermore, compared to acquiring multiple points, the method provided by this invention requires fewer operations but acquires a greater number of points, resulting in better registration accuracy and greater clinical applicability.

[0080] The aspects of this disclosure have been described above with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this disclosure. It should be understood that each block in the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing apparatus to produce a machine such that these instructions, executable via the processor of the computer or other programmable data processing apparatus, enable the implementation of the functions / actions specified in one or more blocks of the flowchart illustrations and / or block diagrams. Such a processor can be, but is not limited to, a general-purpose processor, a special-purpose processor, a special application processor, or a field-programmable logic circuit. It is also understood that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can also be implemented by special-purpose hardware performing the specified functions or actions, or can be implemented by a combination of special-purpose hardware and computer instructions.

[0081] The above description is merely a specific embodiment of this disclosure. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of this disclosure is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in this disclosure, and these modifications or substitutions should all be covered within the protection scope of this disclosure.

Claims

1. A device for camera-CT coordinate system registration in oral implant surgery, characterized in that, It comprises: alveolar, probe, U-shaped groove with scribe groove, infrared binocular camera; wherein the head of the probe is equipped with a reflective ball as a first visual marker, which is recognized by the infrared binocular camera to identify the three-dimensional position, and the tip of the probe is conical; the surface of the U-shaped groove with scribe groove is provided with a plurality of scribe grooves for scribing interaction with the probe; the U-shaped groove with scribe groove is used to be worn on the alveolar by the patient; the infrared binocular camera includes left and right two lenses as a visual navigator, and the infrared binocular camera has a fast point recording function, which can continuously record the coordinate set of the visual marker within a period of time with extremely short time interval.

2. A registration method of a device for registering a camera with a CT coordinate system in dental implant surgery according to claim 1, characterized in that, It comprises the following steps: S101, obtaining oral CBCT image; including: taking CBCT image after the patient wears the U-shaped groove; A three-dimensional model is established to obtain the relative position relationship between the U-shaped groove and the oral CT model, denoted as ; S102, device and system preparation; S103, calibrating the position of the probe tip; S104, obtaining scribe groove point cloud and registering with the U-shaped groove; S105, registering the coordinate system of the infrared binocular camera with the CT coordinate system.

3. The registration method of claim 2, wherein, The device and system preparation in S102 comprises: starting the infrared binocular camera, moving the probe around the patient's mouth and the U-shaped groove to ensure that the infrared binocular camera can stably recognize the first visual marker on the probe.

4. The registration method of claim 2, wherein, The calibration of the position of the probe tip in S103 comprises: establishing the infrared binocular camera coordinate system: the infrared binocular camera coordinate system XYZ takes the left eye of the camera as the coordinate center, the horizontal axis parallel to the camera plane as the X axis, and the outward vertical axis to the camera plane as the Z axis; The probe end touches a coordinate-determined point in the infrared binocular camera calibration space, and the coordinates of the point are the coordinates of the probe end in the infrared binocular camera coordinate system under the current position ; The current coordinates of the three reflective balls in the infrared binocular camera coordinate system are respectively , and ; establishing a probe coordinate system under the probe coordinate system, a relative positional relationship between the first visual marker and the probe tip can be determined , and satisfy: ； As the probe moves, the position of the first visual marker and the position of the probe tip change, but the relative position relationship between the two remains unchanged. remains unchanged.

5. The method of registration of claim 4, wherein, The acquisition of scribe groove point cloud and registration with the U-shaped groove in S104 comprises: placing the tip of the probe at one end of any scribe groove on the U-shaped groove to start scribing, and starting the point recording function of the infrared binocular camera; After the probe is drawn across the entire length of the scribe groove, the point recording is stopped to obtain a set of positions of the retro-reflective spheres in the infrared binocular camera coordinate system 、 and ​ According to the relative position relationship , a set of the infrared binocular camera coordinate system underlined groove point set is calculated; establishing the U-shaped groove coordinate system to obtain the set P of point cloud in the scribe groove of the U-shaped groove in the U-shaped groove coordinate system; corresponding to the point cloud set P in the infrared binocular camera coordinate system corresponding to the point cloud set P in the infrared binocular camera coordinate system , satisfying: 。 6. The method of registration of claim 5, wherein, The registration of the infrared binocular camera coordinate system with the CT coordinate system in S105 comprises: According to the relative position relationship and the conversion matrix of the infrared binocular camera coordinate system and the U-shaped groove coordinate system , obtain the registration conversion relationship T of the infrared binocular camera coordinate system and the CT coordinate system, which satisfies: ； judging whether the registration accuracy meets the standard, if not, re-scribing the U-shaped groove and registering again; if it meets the standard, the registration is ended.

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