Method for switching target implant based on real-time drilling position

Abstract

The invention relates to the technical field of dental treatment, in particular to a method for switching a target implant based on a real-time drilling position, which comprises the following steps: a region hash mapping pre-calculation step and a real-time positioning and automatic switching step. According to the method for switching the target implant based on the real-time drilling position, real-time query of complexity is realized through the pre-calculated global hash table, the operation time is greatly shortened, the operation efficiency is remarkably improved, and the operation efficiency is greatly improved based on voxelized spatial hash mapping in combination with an anti-shake delay mechanism. According to the method, the preset implant area to which the drill bit currently belongs can be accurately, stably and automatically judged, the operation safety is improved, the whole process of drill bit position detection, target implant recognition and navigation interface switching is automatic, seamless synchronization of operation and navigation is achieved, and the operation smoothness and controllability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dental treatment, in particular to a method for switching target implant based on real-time drilling position. BACKGROUND

[0002] Dynamic navigation system has been widely used in oral implant surgery. Through preoperative CT / CBCT three-dimensional reconstruction, real-time tracking and virtual-real superposition during operation, the drilling head is guided like GPS. The system is usually composed of imaging equipment, tracking camera or electromagnetic sensor, surgical reference frame and navigation software, which can display the drilling depth, angle and deviation in real time under three-dimensional image.

[0003] In the case of multiple implant planning, the traditional dynamic navigation needs to be manually clicked by the doctor between different implant positions to view the navigation interface and prompt of the corresponding implant. This process not only interrupts the view, but also may cause potential deviation due to operation delay, affecting the continuity and safety of the operation, consuming several seconds to several tens of seconds, increasing the operation time and cognitive load; under the condition of multiple holes, misselecting the implant or switching delay may cause the drill to deviate from the predetermined trajectory, which has the risk of displacement; frequent interface operation and separation of surgical action reduce the overall usability of the system.

[0004] In order to solve the above problems, we have made improvements and put forward a method for switching target implant based on real-time drilling position. SUMMARY

[0005] In order to solve the above technical problems, the present application provides the following technical scheme:

[0006] The present application provides a method for switching target implant based on real-time drilling position, comprising the following steps:

[0007] S1. Regional hash mapping pre-computation step:

[0008] (a) Parameter acquisition: for each planned implant, the center axis origin P0, terminal point P1, diameter D (radius R = D / 2) and length L = |P1-P0| are acquired in the preoperative planning stage;

[0009] (b) Local coordinate transformation: a local coordinate system with P0 as the origin and the axis direction as the z-axis is established, and the space points in the world coordinate system are mapped to the local coordinate system to simplify the cylindrical sampling;

[0010] (c) Voxel bounding box calculation: in the local coordinate system, the axis-aligned bounding box of the implant cylindrical region is calculated:

[0011] x, y ∈ [-R, R], z ∈ [0, L]

[0012] where the bounding box size is rounded outwards to the nearest preset voxel resolution to fully cover the cylinder;

[0013] (d) Construct a voxel index hash table: iterate through each voxel center (x, y, z) within the bounding box, test if it satisfies:

[0014] x 2 +y 2 ≤R 2 , 0 ≤ z ≤ L

[0015] Record the index of the voxel that passed the test in the set S of implants for this implant i , and inverse transform the index to the world coordinate system, write to the global 3D mapping table V[x][y][z] = i, where i is the implant index number;

[0016] S2. Real-time positioning and automatic switching steps:

[0017] (e) Drill bit coordinate acquisition: Real-time acquisition of the coordinates (X, Y, Z) of the drill bit tip in the world coordinate system;

[0018] (f) Voxel index conversion: Quantize (X, Y, Z) to the nearest voxel center according to the voxel resolution, get the integer index (i, j, k);

[0019] (g) Hash lookup table: directly read implant_id = V[i][j][k]:

[0020] If implant_id = n > 0, it is determined that the drill bit is located in the cylindrical region of implant n;

[0021] If implant_id = 0, it is determined that the drill bit is not in any implant region;

[0022] The query time is constant O(1);

[0023] (h) Anti-shake delay processing: introduce a short residence counter: maintain the current candidate candidate_id and continuous hit count count:

[0024] If implant_id = candidate_id in each frame, then count++; otherwise, reset candidate_id = implant_id, count = 1;

[0025] When candidate_id > 0 and count ≥ N, it is confirmed that it is stable to enter, trigger target switching; when candidate_id == 0 and count ≥ M, trigger the implant region exit event.

[0026] As a preferred technical solution of the present application, V is a three-dimensional region hash, and the lookup of any voxel index is O(1), avoiding the overhead of multi-limb traversal and real-time distance calculation.

[0027] As a preferred technical solution of the present application, in the voxel bounding box calculation, the value range of x and y is [-R, R], and the value range of z is [0, L].

[0028] As a preferred technical solution of the present application, in the anti-shake delay processing, N and M are preset thresholds, corresponding to 100ms and 500ms respectively.

[0029] As a preferred technical solution of the present application, the voxel index conversion uses the rounding method to discretize the continuous coordinates (X, Y, Z) into integer voxel indexes (i, j, k).

[0030] The method for switching target implant based on real-time drilling position has the advantages that: through the pre-computed global hash table, the real-time query complexity is realized, the operation time is greatly shortened, the operation efficiency is significantly improved, based on the voxelized spatial hash mapping, combined with the anti-shake delay mechanism, the current preset implant region to which the drill bit belongs can be accurately and stably automatically determined, the operation safety is improved, the drill bit position detection, target implant identification and navigation interface switching full-process automation are realized, the seamless synchronization of operation and navigation is realized, and the operation fluency and controllability are improved. BRIEF DESCRIPTION OF DRAWINGS

[0031] The accompanying drawings are used to provide a further understanding of the present application, and constitute a part of the specification, together with the embodiments of the present application, for explaining the present application, and do not constitute a limitation on the present application. In the drawings:

[0032] Fig. 1 is a regional hash mapping pre-computation flowchart of the method for switching target implant based on real-time drilling position of the present application;

[0033] Fig. 2 is a real-time positioning and automatic switching flowchart of the method for switching target implant based on real-time drilling position of the present application; DETAILED DESCRIPTION

[0034] The preferred embodiments of the present application are described below in combination with the drawings, and it should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application, and do not limit the present application.

[0035] Embodiment: As shown in the figure, the method for switching target implant based on real-time drilling position comprises the following steps: Figs. 1-2

[0036] S1. Regional hash mapping pre-computation step: ​

[0037] (a) Parameter acquisition: For each planned implant, the center axis origin P0, the end point P1, the diameter D (radius R = D / 2), and the length L = |P1-P0| are acquired in the preoperative planning stage;

[0038] (b) Local coordinate transformation: A local coordinate system is established with P0 as the origin and the axis direction as the z-axis, and the space points in the world coordinate system are mapped to the local coordinate system to simplify the cylinder sampling;

[0039] (c) Voxel bounding box calculation: In the local coordinate system, the axis-aligned bounding box of the implant cylindrical region is calculated:

[0040] x, y ∈ [-R, R], z ∈ [0, L]

[0041] Where the bounding box size is rounded outwards according to the preset voxel resolution to completely cover the cylinder;

[0042] (d) Constructing voxel index hash table: Traverse each voxel center (x, y, z) in the bounding box, test whether it satisfies:

[0043] x 2 +y 2 ≤R 2 , 0 ≤ z ≤ L

[0044] Record the index of the voxel that passes the test in the set S i of the implant, and convert the index to the world coordinate system and write it into the global three-dimensional mapping table V[x][y][z] = i, where i is the implant index number;

[0045] S2. Real-time positioning and automatic switching step:

[0046] (e) Drill bit coordinate acquisition: Real-time acquisition of the coordinates (X, Y, Z) of the drill bit tip in the world coordinate system;

[0047] (f) Voxel index conversion: Quantize (X, Y, Z) to the nearest voxel center according to the voxel resolution, and get the integer index (i, j, k);

[0048] (g) Hash lookup table: Directly read implant_id = V[i][j][k]:

[0049] If implant_id = n > 0, it is determined that the drill bit is located in the cylindrical region of implant n;

[0050] If implant_id = 0, it is determined that the drill bit is not in any implant region;

[0051] The query time is constant O(1);

[0052] (h) Anti-shake delay processing: introduce a short residence counter: maintain the current candidate_id and continuous hit count count:

[0053] If implant_id == candidate_id, then count ++; otherwise reset candidate_id = implant_id, count = 1;

[0054] When candidate_id > 0 and count >= N, it is confirmed that it is stable to enter, and the target switching is triggered; when candidate_id == 0 and count >= M, the implant region event is triggered.

[0055] V is a three-dimensional region hash, and the lookup of any voxel index is O(1), avoiding the overhead of multi-limb traversal and real-time distance calculation.

[0056] In the voxel bounding box calculation, the value range of x and y is [-R, R], and the value range of z is [0, L].

[0057] In the anti-shake delay processing, N and M are preset thresholds, corresponding to 100ms and 500ms respectively.

[0058] The voxel index conversion uses the rounding method to discretize the continuous coordinates (X, Y, Z) into integer voxel indexes (i, j, k).

[0059] Finally, it should be noted that: the above only describes the preferred embodiments of the present application and is not used to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, for those skilled in the art, the technical solutions recorded in the foregoing embodiments can still be modified, or some technical features can be replaced. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for switching target implants based on real-time downhole position, characterized by, The method comprises the following steps: S1. A region hash mapping pre-computation step: (a) Parameter acquisition: for each planned implant, the starting point P0, the ending point P1, the diameter D (radius R = D / 2), and the length L = |P1-P0| of the central axis are acquired in the preoperative planning stage; (b) Local coordinate transformation: a local coordinate system is established with P0 as the origin and the axis direction as the z-axis, and the spatial points in the world coordinate system are mapped to the local coordinate system to simplify the cylinder sampling; (c) Voxel bounding box calculation: in the local coordinate system, the axis-aligned bounding box of the implant cylindrical region is calculated: x, y ∈ [-R, R], z ∈ [0, L] where the bounding box size is rounded outwards according to the preset voxel resolution to completely cover the cylinder; (d) Constructing a voxel index hash table: traverse each voxel center (x, y, z) in the bounding box, and test whether it satisfies: x 2 +y 2 ≤R 2 , 0≤z≤L The indices of the voxels that pass the test are recorded in the set S of implants i and the indices are inverse-transformed to the world coordinate system and written to the global three-dimensional map table V[x][y][z] = i, where i is the implant index number; S2. Real-time positioning and automatic switching step: (e) Drill bit coordinate acquisition: the coordinates (X, Y, Z) of the drill bit tip in the world coordinate system are acquired in real time; (f) Voxel index conversion: quantize (X, Y, Z) to the nearest voxel center according to the voxel resolution, and get the integer index (i, j, k); (g) Hash lookup table: directly read implant_id = V[i][j][k]: If implant_id = n > 0, it is determined that the drill bit is located in the cylindrical region of implant n; If implant_id = 0, it is determined that the drill bit is not in any implant region; The query time is constant 0(1); (h) Anti-shake delay processing: introduce a short residence counter: maintain the current candidate candidate_id and continuous hit count count: If implant_id = candidate_id each frame, then count++, otherwise reset candidate_id = implant_id, count = 1; When candidate_id > 0 and count >= N, it is confirmed that it is stable to enter, and the target switching is triggered; When candidate_id == 0 and count >= M, the implant region event is triggered.

2. The method of claim 1, wherein, V is a three-dimensional region hash, and the lookup of any voxel index is 0(1), avoiding the overhead of multi-limb traversal and real-time distance calculation.

3. The method of claim 1, wherein, In the voxel bounding box calculation, the value range of x and y is [-R, R], and the value range of z is [0, L].

4. The method of claim 1, wherein the target implant is switched based on the real-time downhole position. In the anti-shake delay processing, N and M are preset thresholds, corresponding to 100ms and 500ms respectively.

5. The method of claim 1, wherein, The voxel index conversion uses the rounding method to discretize the continuous coordinates (X, Y, Z) into integer voxel indexes (i, j, k).

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