A laser navigation calibration method

Abstract

The embodiment of the application provides a kind of laser navigation calibration method, comprising: the calibration board is fixed in parallel with the first position of the first distance spaced from detector;Control laser module is tilted to project laser to calibration board, and the first depth image of calibration board is photographed by depth camera, and the first detection image of calibration board is obtained by detector;The calibration board is fixed in parallel with the second position of the second distance spaced from the detector, and the second depth image of calibration board is photographed by depth camera, and the second detection image of calibration board is obtained by detector;According to first depth image, second depth image, first detection image and second detection image, the incidence angle of laser module and the position mapping relationship of laser module and detector are calculated.The embodiment of the application realizes the calibration of laser module.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of laser navigation, in particular to a laser navigation calibration method. BACKGROUND

[0002] With the development of science and technology, more and more new technologies are applied to medical operations. Minimally invasive surgery performed by a mechanical arm is becoming more and more popular due to its small surgical incision and fast postoperative recovery. Especially in orthopedic surgery, due to the small size of the lesion point and the complex and sensitive environment of the lesion point, traditional orthopedic surgery requires high surgical experience and medical technology, especially for spinal surgery.

[0003] Since the lesion point of common orthopedic surgery is small and inconvenient to observe, traditional orthopedic surgery generally requires a large incision, which causes great trauma to the patient, a long postoperative recovery period, and high intraoperative risk. However, through the cooperation of a high-precision mechanical arm and a navigation system, surgery can be completed with a small incision. In related technologies, a navigation system performs surgical navigation by cooperating with a C-arm machine. Such equipment is complex to operate, has high equipment costs, and high surgical costs, resulting in a low popularization rate. SUMMARY

[0004] To solve the problem of orthopedic surgery navigation, the present application provides a laser navigation calibration method for a fluoroscopy device, which includes a probe and a laser module. The laser module is installed on the probe, and a depth camera is also installed on the probe. The method comprises:

[0005] A calibration board is fixed in parallel at a first position at a first distance from the probe. The calibration board is provided with marks that can be detected by the probe.

[0006] The laser module is controlled to project laser light obliquely to the calibration board, and a first depth image of the calibration board is captured by the depth camera. A first detection image of the calibration board is obtained by the probe.

[0007] The calibration board is fixed in parallel at a second position at a second distance from the probe. The second distance is different from the first distance. A second depth image of the calibration board is captured by the depth camera, and a second detection image of the calibration board is obtained by the probe.

[0008] According to the first positional relationship between the center point of the mark and the laser projection point in the first depth image, the first depth information of the calibration board, the second positional relationship between the center point of the mark and the laser projection point in the second depth image, and the second depth information of the calibration board, an incident angle of the laser module is calculated to obtain an angle calibration relationship between the laser module and the detector, wherein the center point of the mark is obtained according to the first detection image or the second detection image.

[0009] According to the second positional relationship, the second depth information, and the incident angle, a position mapping relationship between the laser module and the detector is obtained.

[0010] In some embodiments, the mark is arranged at a top corner of the calibration board.

[0011] In some embodiments, four crosshairs that are centrally symmetric around a center point of the calibration board are arranged on the calibration board, and the crosshairs are the marks.

[0012] In some embodiments, according to the first positional relationship between the center point of the mark and the laser projection point in the first depth image, the first depth information of the calibration board, the second positional relationship between the center point of the mark and the laser projection point in the second depth image, and the second depth information of the calibration board, the incident angle of the laser module is calculated, including:

[0013] The first depth image and the first detection image are fused to obtain a first fused image;

[0014] The second depth image and the second detection image are fused to obtain a second fused image;

[0015] A coordinate system is established in the first fused image and the second fused image, respectively, wherein a coordinate origin of the coordinate system is arranged as a center point of the first fused image or the second fused image, and the center points of the first fused image and the second fused image are projections of a center point of the detector;

[0016] Based on the coordinate system, the first depth information and the second depth information of the calibration board, the first positional relationship between the center point of the mark and the laser projection point in the first depth image, and the second positional relationship between the center point of the mark and the laser projection point in the second depth image, the incident angle of the laser module is calculated by a trigonometric function.

[0017] In some embodiments, the mark is a crosshair, an x-axis of the coordinate system is parallel to one side of the crosshair, and a y-axis of the coordinate system is parallel to another side of the crosshair.

[0018] In some embodiments, the position mapping relationship between the laser module and the detector is obtained according to the second position relationship, the second depth information, and the incident angle, including:

[0019] The position mapping relationship between the laser module and the detector is determined by calculating the distance between the position of the laser module on the detector and the center point of the detector based on the second position relationship, the second depth information, and the incident angle through a trigonometric function relationship.

[0020] In some embodiments, the depth camera and the detector are flush with the plane of the detection plate.

[0021] In some embodiments, the perspective imaging device includes a display electrically connected to the detector, for displaying the first detection image and the second detection image obtained by the detector.

[0022] In some embodiments, the laser module includes a first laser source and a second laser source, and the first laser source and the second laser source are distributed on two adjacent and perpendicular sides of the detector.

[0023] In some embodiments, the depth camera and the detector are flush with the plane of the detection plate. In some embodiments, the depth camera and the detector are flush with the plane of the detection plate.

[0024] The laser navigation calibration method and the offset angle measurement method provided by the present application have the following beneficial effects:

[0025] The laser navigation calibration method provided by the present application can complete the position and angle calibration of the laser module through the calibration plate and the depth camera, and requires fewer tools and has lower calibration cost. The calibration plate used in the embodiments of the present application is provided with marks that can be detected by the detector. Based on the correspondence between the depth image captured by the depth camera and the detection image of the detector, the preoperative rapid calibration of the laser module is realized, which is conducive to the popularization of laser navigation in orthopedic surgery. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions of the present application, the drawings needed in the embodiments will be briefly introduced below. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings.

[0027] Figure 1 Fig. 1 exemplarily shows a structural schematic diagram of an X-ray machine;

[0028] Figure 2 Fig. 2 exemplarily shows a bottom view of a detector;

[0029] Figure 3 A side view of a detector is exemplarily shown in FIG. 1;

[0030] Figure 4 A schematic diagram of a detection scenario of X-ray is exemplarily shown in FIG. 2;

[0031] Figure 5 A flowchart of a laser navigation calibration method is exemplarily shown in FIG. 3;

[0032] Figure 6 A schematic diagram of a calibration board is exemplarily shown in FIG. 4;

[0033] Figure 7 A schematic diagram of a calibration board in a first position is exemplarily shown in FIG. 5;

[0034] Figure 8 A schematic diagram of a calibration board in a second position is exemplarily shown in FIG. 6;

[0035] Figure 9 A schematic diagram of a first depth image is exemplarily shown in FIG. 7;

[0036] Figure 10 A schematic diagram of a first detection image is exemplarily shown in FIG. 8;

[0037] Figure 11 A schematic diagram of a first fusion image is exemplarily shown in FIG. 9. DETAILED DESCRIPTION

[0038] For the purpose of making the objects and implementation manners of the present application more clear, the present application will be described clearly and completely below in conjunction with the drawings in the exemplary embodiments of the present application. Obviously, the described exemplary embodiments are only some of the embodiments of the present application, but not all of the embodiments of the present application.

[0039] It should be noted that the brief description of the terms in the present application is only for the convenience of understanding the following described embodiments, and is not intended to limit the embodiments of the present application. Unless otherwise specified, these terms should be understood according to their ordinary and general meanings.

[0040] The terms "first", "second", "third", and the like in the specification and claims of the present application and the above drawings are used to distinguish similar or similar objects or entities, and do not necessarily mean to limit the specific order or sequence, unless otherwise specified. It should be understood that the terms used in this way can be interchanged under appropriate circumstances.

[0041] The terms "comprises", "comprising", "includes", "including", "has", "having" and their conjugates mean, when used in this document, that the mentioned features are included, but not to the exclusion of other features. In other words, the terms "comprises", "comprising", "includes", "including", "has", "having" and their conjugates mean that the mentioned features are included, but that other features are not excluded.

[0042] The presently disclosed embodiments will now be described in detail with reference to the drawings, in which like reference numerals indicate identical or corresponding elements throughout the several views.

[0043] The embodiments of the present application provide a laser navigation calibration method for a perspective imaging device, the mechanism of the perspective imaging device can be an X-ray machine, referring to Figure 1 , a structural schematic diagram of an X-ray machine is provided for the embodiments of the present application, as shown in Figure 1 , the X-ray machine comprises a head assembly 1, a detector shell 2, a laser module 3 and a detector 4, wherein the laser module 3 is installed on the detector shell 2 of the detector 4, and the center of the head assembly 1 and the center of the detector 4 are on the same axis.

[0044] Referring to Figure 2 , a bottom view schematic diagram of the detector is provided, as shown in Figure 2 , the laser module 3 can comprise a first laser source 31 and a second laser source 32. Wherein the first laser source 31 and the second laser source 32 are arranged on the adjacent two sides of the detector 4, so as to project a cross laser line below the detector 4, and the first laser source 31 and the second laser source 32 can reciprocate along the direction shown in the figure to adjust the position of the cross laser line.

[0045] Referring to Figure 3 , a side view schematic diagram of the detector is provided, as shown in Figure 3 , taking the first laser source 31 as an example, the laser projection point of the first laser source 31 on the obstacle between the detector 4 and the head assembly 1 is a laser point 11, and the first laser source 31 can rotate around a first rotation fulcrum 12 perpendicular to the plane of the detector 4 to change the incidence angle θ1 of the first laser source 31, and similarly, the second laser source 32 can rotate around a second rotation fulcrum 13 perpendicular to the plane of the detector 4 to change the incidence angle θ2 of the second laser source 32.

[0046] Based on Figures 1-3 , an X-ray detection scene can be referred to Figure 4 , as shown in Figure 4As shown, the X-ray machine also includes a display 5 electrically connected to the detector. The object under test 6 is fixed between the head assembly 1 and the detector 4. The laser module 3 projects a cross laser line onto the object under test 6. An X-ray image of the object under test can be obtained through the detector 4. The cross laser line on the object under test 6 cannot be detected by the detector 4, therefore, the cross laser line is not displayed on the X-ray image.

[0047] During the operation on the subject, the position of the laser point 11 of the cross laser line on the X-ray image is the target execution position of the surgical instrument. In order to facilitate the operator's observation on the X-ray image, the cross laser line corresponding to the laser module 3 can be virtually drawn on the X-ray image. In order to draw the virtual cross laser line, the relative position of the laser module 3 and the detector 4 needs to be calibrated.

[0048] See Figure 5 This application provides a laser navigation calibration method, such as... Figure 5 As shown, the method may include the following steps:

[0049] Step S101: Fix the calibration plate parallel to the detector at a first position at a first distance from the detector, wherein the calibration plate is provided with a mark that can be detected by the detector.

[0050] In some embodiments, see Figure 6 This is a schematic diagram of a calibration board used in an embodiment of this application, as shown below. Figure 6 As shown, the calibration plate 13 can be a rectangular plate, and it can be provided with marks that can be detected by the detector 4, such as crosshairs. Four crosshairs 131, arranged symmetrically around the center point of the calibration plate 13, can be provided on the calibration plate 13, and the physical length of each crosshair 131 is a. These crosshairs 131 can be detected by the detector 4 and imaged on an X-ray image.

[0051] Before performing the surgery, to calibrate the angles and relative positions of laser module 3 and detector 4, the following steps can be taken: Figure 6 The calibration plate 13 shown is fixed in the first position between the detector 4 and the head assembly 1, replacing the object under test 6, so that the crosshair 131 faces the detector 4.

[0052] Step S102: Control the laser module to tilt and project the laser onto the calibration plate, and capture the first depth image of the calibration plate through the depth camera, and obtain the first detection image of the calibration plate through the detector.

[0053] In some embodiments, after the calibration plate 13 is fixed in the first position, see Figure 7The first laser source 31 in the laser module 3 can be controlled to tilt and project a laser onto the calibration plate 13, and the first laser source 32 in the laser module 3 can be controlled to tilt and project a laser onto the calibration plate 13. At this time, the incident angle of the first laser source 31 is θ1, the incident angle of the second laser source 32 is θ2, the magnitudes of θ1 and θ2 are unknown, and the center point of the crosshair 131 on the calibration plate 13 is p1.

[0054] In some embodiments, the X-ray machine may also be equipped with a depth camera 15, such as Figure 7 As shown, the depth camera 15 can be mounted on the detector 4, facing the calibration plate 13. The depth camera 15 can capture a depth image of the calibration plate 13, which is recorded as the first depth image. The first depth image contains the depth information of the calibration plate 13, which is recorded as the first depth information. If the depth camera 15 is mounted below the detector 4, the distance H1 between the calibration plate 13 and the detector 4 at the first position can be obtained from the sum of the first depth information and the height of the depth camera 15 itself. If the depth camera 15 is mounted at a height parallel to the detector 4, the first depth information is the distance H1 between the calibration plate 13 and the detector 4 at the first position. The height difference between the rotation fulcrum 12 of the first laser source 31 and the bottom of the detector 4 is recorded as h.

[0055] In some embodiments, a detection image of the calibration plate 13 is also acquired by the detector 4, and this detection image is denoted as the first detection image.

[0056] Step S103: Fix the calibration plate parallel to the detector at a second position at a second distance, which is different from the first distance. Take a second depth image of the calibration plate with the depth camera and obtain a second detection image of the calibration plate with the detector.

[0057] In some embodiments, after capturing the first depth image, see Figure 8 Without changing the projection angle of the laser module 3, the first calibration plate 13 is moved parallel to and fixed to a second position between the detector 4 and the head assembly 1. The depth image of the calibration plate 13 is then captured again by the depth camera 15. At this time, the incident angle of the first laser source 31 is still θ1, and the center point of the crosshair 131 on the calibration plate 13 is p2. This depth image is recorded as the second depth image, which contains the depth information of the calibration plate 13. This depth information is recorded as the second depth information. The distance H2 between the calibration plate 13 and the detector 4 can be obtained based on the second depth information.

[0058] In some embodiments, a detection image of the calibration plate 13 is also acquired by the detector 4, and this detection image is denoted as the second detection image.

[0059] Step S104: according to the first positional relationship between the center point of the mark and the laser projection point in the first depth image, the first depth information of the calibration board, the second positional relationship between the center point of the mark and the laser projection point in the second depth image, and the second depth information of the calibration board, the incidence angle of the laser module is calculated to obtain the angle calibration relationship between the laser module and the detector, wherein the center point of the mark is obtained according to the first detection image or the second detection image.

[0060] In some embodiments, the angle calibration relationship between the laser module and the detector includes the incidence angle θ1 of the first laser source 31 and the incidence angle θ2 of the second laser source 32.

[0061] In some embodiments, the first positional relationship between the center point of the cross lead mark 131 and the laser projection point p1 can be obtained according to the first depth image, and the second positional relationship between the center point of the cross lead mark 131 and the laser projection point p2 can be obtained according to the second depth image.

[0062] Referring to Figure 9 , a schematic diagram of a first depth image obtained by a depth camera when the calibration board 13 is located at a first position, Figure 9 , the center point of the cross laser line 7 projected by the laser module 3 on the calibration board 13 is p1. One of the cross lead marks 131, such as the cross lead mark at the upper left corner, is set as a reference mark, the first directional distance between the center point of the reference mark and p1 is recorded as L1, and the second directional distance between the center point of the reference lead mark and p1 is recorded as V1, wherein the first direction is the reciprocating motion direction of the first laser source 31, and the second direction is the reciprocating motion direction of the second laser source 32, and the first positional relationship includes the first directional distance and the second directional distance between the center point of the reference mark and p1.

[0063] Referring to Figure 10 , a schematic diagram of a first detection image obtained by the detector 4 when the calibration board 13 is located at a first position, Figure 10 , a coordinate system is established with the center of the first detection image as the origin O, the first direction as the x-axis direction, and the second direction as the y-axis direction, and the distance between the center point of the reference mark and the origin O in the x-axis direction is T1, and the distance between the center point of the reference mark and the origin O in the y-axis direction is S1.

[0064] In some embodiments, the first depth image and the first detection image can be image fused according to the position of the reference mark 131 to obtain a first fused image as shown in Figure 11 , referring to Figure 11Based on the first fused image, the distance x1 between the laser projection point P1 and the origin O in the x-axis direction can be obtained as: x1 = T1 - L1, and the distance y1 between the center point P1 of the laser projection point and the origin O in the y-axis direction can be obtained as: y1 = V1 - S1.

[0065] Similarly, in the second depth image, the distance in the first direction between the center point of the reference marker and the laser projection point p2 is L2, and the distance in the second direction between the center point of the reference marker and p2 is V2. The second positional relationship includes the distance in the first direction and the distance in the second direction between the center point of the reference marker and p2. In the second detection image, the distance between the center point of the reference marker and the origin O in the x-axis direction is T2, and the distance between the center point of the reference marker and the origin O in the y-axis direction is S2. After fusing the second depth image and the second detection image, a second fused image can be obtained. Based on this second fused image, the distance x2 between the laser projection point P2 and the origin O in the x-axis is x2 = T2 - L2, and the distance y2 between the laser projection point P2 and the origin O in the y-axis is y2 = V2 - S2.

[0066] In some embodiments, after obtaining x1 and x2, the incident angle θ1 of the first laser source 31 can be obtained based on trigonometric relationships. For example... Figure 8 As shown, the rotation fulcrum of the first laser source 31 is denoted as e, the projection point of the laser projection point P2 on the detector 4 is denoted as d, and the intersection point of the line connecting p2 and d with the calibration plate 13 at the first position on the laser projection plane is c. Therefore, we can obtain: side length p1c = (T1-L1)-(T2-L2); side length p2c = H2-H1. According to trigonometric functions, we can obtain:

[0067]

[0068] Similarly, after obtaining y1 and y2, the incident angle θ2 of the second laser source 32 can be obtained based on the trigonometric function relationship.

[0069] Step S105: Based on the second positional relationship, the second depth information, and the incident angle, obtain the positional mapping relationship between the laser module and the detector.

[0070] In some embodiments, after obtaining the incident angle θ1 of the first laser source 31, the position mapping relationship between the laser module and the detector can be calculated through trigonometric functions.

[0071] In some embodiments, the positional mapping relationship between the first laser source 31 and the detector can be represented by the positional mapping relationship between the rotation pivot 12 and the center point q of the detector 4, or it can be represented by the positional mapping relationship between the rotation pivot 12 and other positions on the detector 4, such as one of the vertex corners of the detector. For example, the positional mapping relationship between the first laser source 31 and the detector can be represented by the positional mapping relationship between the rotation pivot 12 and the center point q of the detector 4. Figure 8 As shown, the projection point of the center point q of detector 4 on the calibration plate 13 at the first position is O1, and the projection point on the calibration plate 13 at the second position is O2. Figures 10-11 In the right triangle p2de, O1 coincides with the origin O. Therefore, in p2de, p2d = H2 + h, and de = (H2 + h)tanθ1. Since p2O2 = T2 - L2, the positional mapping relationship M1 between the rotation fulcrum 12 and the center point q of detector 4 is:

[0072] M1 = de + (T2 - L2)

[0073] based on Figure 5 After obtaining the calibration of the incident angle θ1 of the first laser source 31 and completing the calibration of the position mapping relationship M1 between the first laser source 31 and the detector 4 by the method shown, the calibration of the incident angle θ2 of the second laser source 32 and completing the calibration of the position mapping relationship M2 between the second laser source 32 and the detector 4 can be obtained by referring to the same method, thereby completing the calibration of the laser navigation of the X-ray machine.

[0074] As can be seen from the above embodiments, the laser navigation calibration method proposed in this application can complete the position and angle calibration of the laser module using a calibration plate and a depth camera, requiring fewer tools and having lower calibration costs. The calibration plate used in this application is equipped with marks that can be detected by the detector. Based on the trigonometric function relationship between the depth image captured by the depth camera and the detection image of the detector, rapid preoperative calibration of the laser module is achieved, which is conducive to the popularization of laser navigation in orthopedic surgery.

[0075] Since the above embodiments are all described in conjunction with other methods, and different embodiments have the same parts, the same or similar parts between the various embodiments in this specification can be referred to mutually. They will not be described in detail here.

[0076] The above embodiments of this application do not constitute a limitation on the scope of protection of this application.

Claims

1. A laser navigation calibration method, characterized by, The method is used for perspective imaging equipment, the perspective imaging equipment comprises a detector and a laser module, wherein the laser module is installed on the detector, and a depth camera is also installed on the detector, and the method comprises the following steps: a calibration board is fixed in parallel at a first position at a first distance from the detector, wherein the calibration board is provided with a mark capable of being detected by the detector; the laser module is controlled to project laser light obliquely to the calibration board, and a first depth image of the calibration board is captured by the depth camera, and a first detection image of the calibration board is obtained by the detector; the calibration board is fixed in parallel at a second position at a second distance from the detector, the second distance being different from the first distance, and a second depth image of the calibration board is captured by the depth camera, and a second detection image of the calibration board is obtained by the detector; an incident angle of the laser module is calculated according to a first positional relationship between a center point of the mark and a laser projection point in the first depth image, first depth information of the calibration board, a second positional relationship between the center point of the mark and the laser projection point in the second depth image, and second depth information of the calibration board, so as to obtain an angle calibration relationship between the laser module and the detector, wherein the center point of the mark is obtained according to the first detection image or the second detection image; a position mapping relationship between the laser module and the detector is obtained according to the second positional relationship, the second depth information and the incident angle.

2. The laser navigation calibration method of claim 1, wherein, The mark is arranged at a top corner of the calibration board.

3. The laser navigation calibration method of claim 1, wherein, Four cross-shaped lead marks that are centrally symmetric around a center point of the calibration board are arranged on the calibration board, and the cross-shaped lead marks are the marks.

4. The laser navigation calibration method of claim 1, wherein, The method for calculating the incident angle of the laser module according to the first positional relationship between the center point of the mark and the laser projection point in the first depth image, the first depth information of the calibration board, the second positional relationship between the center point of the mark and the laser projection point in the second depth image, and the second depth information of the calibration board comprises the following steps: the first depth image and the first detection image are fused to obtain a first fused image; the second depth image and the second detection image are fused to obtain a second fused image; coordinate systems are respectively established in the first fused image and the second fused image, wherein a coordinate origin of the coordinate system is arranged as a center point of the first fused image or the second fused image, and the center points of the first fused image and the second fused image are projections of a center point of the detector; the incident angle of the laser module is calculated by a trigonometric function based on the coordinate system, the first depth information and the second depth information of the calibration board, the first positional relationship between the center point of the mark and the laser projection point in the first depth image, and the second positional relationship between the center point of the mark and the laser projection point in the second depth image.

5. The laser navigation calibration method of claim 4, wherein, The mark is a cross-shaped lead mark, an x-axis of the coordinate system is parallel to one side of the cross-shaped lead mark, and a y-axis of the coordinate system is parallel to the other side of the cross-shaped lead mark.

6. The laser navigation calibration method of claim 4, wherein, According to the second position relationship, the second depth information and the incident angle, a position mapping relationship between the laser module and the detector is obtained, including: Based on the second position relationship, the second depth information and the incident angle, a distance between the position of the laser module on the detector and the center point of the detector is calculated through a trigonometric function relationship, and the distance and the incident angle are determined as the position mapping relationship between the laser module and the detector.

7. The laser navigation calibration method of claim 1, wherein, The depth camera and the detector are flush with the plane of the calibration board.

8. The laser navigation calibration method of claim 1, wherein, The perspective imaging device comprises a display electrically connected with the detector, for displaying the first detection image and the second detection image obtained by the detector.

9. The laser navigation calibration method of claim 1, wherein, The laser module comprises a first laser source and a second laser source, and the first laser source and the second laser source are distributed on two adjacent and perpendicular sides of the detector.

10. The laser navigation calibration method of claim 1, wherein, The depth camera is installed below the detector.

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